Real-time positioning in logging: Effects of forest stand characteristics, topography, and line-of-sight obstructions on GNSS-RF transponder accuracy and radio signal propagation

PubMed Central

2018-01-01

Real-time positioning on mobile devices using global navigation satellite system (GNSS) technology paired with radio frequency (RF) transmission (GNSS-RF) may help to improve safety on logging operations by increasing situational awareness. However, GNSS positional accuracy for ground workers in motion may be reduced by multipath error, satellite signal obstruction, or other factors. Radio propagation of GNSS locations may also be impacted due to line-of-sight (LOS) obstruction in remote, forested areas. The objective of this study was to characterize the effects of forest stand characteristics, topography, and other LOS obstructions on the GNSS accuracy and radio signal propagation quality of multiple Raveon Atlas PT GNSS-RF transponders functioning as a network in a range of forest conditions. Because most previous research with GNSS in forestry has focused on stationary units, we chose to analyze units in motion by evaluating the time-to-signal accuracy of geofence crossings in 21 randomly-selected stands on the University of Idaho Experimental Forest. Specifically, we studied the effects of forest stand characteristics, topography, and LOS obstructions on (1) the odds of missed GNSS-RF signals, (2) the root mean squared error (RMSE) of Atlas PTs, and (3) the time-to-signal accuracy of safety geofence crossings in forested environments. Mixed-effects models used to analyze the data showed that stand characteristics, topography, and obstructions in the LOS affected the odds of missed radio signals while stand variables alone affected RMSE. Both stand characteristics and topography affected the accuracy of geofence alerts. PMID:29324794

Studies of RF sheaths and diagnostics on IShTAR

NASA Astrophysics Data System (ADS)

Crombé, K.; Devaux, S.; D'Inca, R.; Faudot, E.; Faugel, H.; Fünfgelder, H.; Heuraux, S.; Jacquot, J.; Louche, F.; Moritz, J.; Ochoukov, R.; Tripsky, M.; Van Eester, D.; Wauters, T.; Noterdaeme, J.-M.

2015-12-01

IShTAR (Ion cyclotron Sheath Test ARrangement) is a linear magnetised plasma test facility for RF sheaths studies at the Max-Planck-Institut für Plasmaphysik in Garching. In contrast to a tokamak, a test stand provides more liberty to impose the parameters and gives better access for the instrumentation and antennas. The project will support the development of diagnostic methods for characterising RF sheaths and validate and improve theoretical predictions. The cylindrical vacuum vessel has a diameter of 1 m and is 1.1 m long. The plasma is created by an external cylindrical plasma source equipped with a helical antenna that has been designed to excite the m=1 helicon mode. In inductive mode, plasma densities and electron temperatures have been characterised with a planar Langmuir probe as a function of gas pressure and input RF power. A 2D array of RF compensated Langmuir probes and a spectrometer are planned. A single strap RF antenna has been designed; the plasma-facing surface is aligned to the cylindrical plasma to ease the modelling. The probes will allow direct measurements of plasma density profiles in front of the RF antenna, and thus a detailed study of the density modifications induced by RF sheaths, which influences the coupling. The RF antenna frequency has been chosen to study different plasma wave interactions: the accessible plasma density range includes an evanescent and propagative behaviour of slow or fast waves, and allows the study of the effect of the lower hybrid resonance layer.

RF low-level control for the Linac4 H{sup −} source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Butterworth, A., E-mail: andrew.butterworth@cern.ch; Grudiev, A.; Lettry, J.

2015-04-08

The H{sup −} source for the Linac4 accelerator at CERN uses an RF driven plasma for the production of H{sup −}. The RF is supplied by a 2 MHz RF tube amplifier with a maximum power output of 100 kW and a pulse duration of up to 2 ms. The low-level RF signal generation and measurement system has been developed using standard CERN controls electronics in the VME form factor. The RF frequency and amplitude reference signals are generated using separate arbitrary waveform generator channels. The frequency and amplitude are both freely programmable over the duration of the RF pulse, which allowsmore » fine-tuning of the excitation. Measurements of the forward and reverse RF power signals are performed via directional couplers using high-speed digitizers, and permit the estimation of the plasma impedance and deposited power via an equivalent circuit model. The low-level RF hardware and software implementations are described, and experimental results obtained with the Linac4 ion sources in the test stand are presented.« less

Saddle antenna radio frequency ion sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dudnikov, V., E-mail: vadim@muonsinc.com; Johnson, R.; Murray, S.

Existing RF ion sources for accelerators have specific efficiencies for H{sup +} and H{sup −} ion generation ∼3–5 mA/cm{sup 2} kW, where about 50 kW of RF power is typically needed for 50 mA beam current production. The Saddle Antenna (SA) surface plasma source (SPS) described here was developed to improve H{sup −} ion production efficiency, reliability, and availability. In SA RF ion source, the efficiency of positive ion generation in the plasma has been improved to 200 mA/cm{sup 2} kW. After cesiation, the current of negative ions to the collector was increased from 1 mA to 10 mA withmore » RF power ∼1.5 kW in the plasma (6 mm diameter emission aperture) and up to 30 mA with ∼4 kW RF. Continuous wave (CW) operation of the SA SPS has been tested on the test stand. The general design of the CW SA SPS is based on the pulsed version. Some modifications were made to improve the cooling and cesiation stability. CW operation with negative ion extraction was tested with RF power up to ∼1.2 kW in the plasma with production up to Ic = 7 mA. A stable long time generation of H{sup −} beam without degradation was demonstrated in RF discharge with AlN discharge chamber.« less

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gupta, Prabhat Kumar; Rabehl, Roger

2014-07-01

Fermilab Vertical Test Stand-1 (VTS-1) is in operation since 2007 for testing the superconducting RF cavities at 2 K. This test stand has single layer coiled finned tubes heat exchanger before J-T valve. A finite difference based thermal model has been developed in Engineering Equation Solver (EES) to study its thermal performance during filling and refilling to maintain the constant liquid level of test stand. The model is also useful to predict its performance under other various operating conditions and will be useful to design the similar kind of heat exchanger for future needs. Present paper discusses the different operationalmore » modes of this heat exchanger and its thermal characteristics under these operational modes. Results of this model have also been compared with the experimental data gathered from the VTS-1 heat exchanger and they are in good agreement with the present model.« less

Studies of RF sheaths and diagnostics on IShTAR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crombé, K., E-mail: Kristel.Crombe@UGent.be; LPP-ERM/KMS, Royal Military Academy, Brussels; Devaux, S.

2015-12-10

IShTAR (Ion cyclotron Sheath Test ARrangement) is a linear magnetised plasma test facility for RF sheaths studies at the Max-Planck-Institut für Plasmaphysik in Garching. In contrast to a tokamak, a test stand provides more liberty to impose the parameters and gives better access for the instrumentation and antennas. The project will support the development of diagnostic methods for characterising RF sheaths and validate and improve theoretical predictions. The cylindrical vacuum vessel has a diameter of 1 m and is 1.1 m long. The plasma is created by an external cylindrical plasma source equipped with a helical antenna that has been designed tomore » excite the m=1 helicon mode. In inductive mode, plasma densities and electron temperatures have been characterised with a planar Langmuir probe as a function of gas pressure and input RF power. A 2D array of RF compensated Langmuir probes and a spectrometer are planned. A single strap RF antenna has been designed; the plasma-facing surface is aligned to the cylindrical plasma to ease the modelling. The probes will allow direct measurements of plasma density profiles in front of the RF antenna, and thus a detailed study of the density modifications induced by RF sheaths, which influences the coupling. The RF antenna frequency has been chosen to study different plasma wave interactions: the accessible plasma density range includes an evanescent and propagative behaviour of slow or fast waves, and allows the study of the effect of the lower hybrid resonance layer.« less

Experimental observation of standing wave effect in low-pressure very-high-frequency capacitive discharges

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Yong-Xin; Gao, Fei; Liu, Jia

2014-07-28

Radial uniformity measurements of plasma density were carried out by using a floating double probe in a cylindrical (21 cm in electrode diameter) capacitive discharge reactor driven over a wide range of frequencies (27–220 MHz). At low rf power, a multiple-node structure of standing wave effect was observed at 130 MHz. The secondary density peak caused by the standing wave effect became pronounced and shifts toward the axis as the driving frequency further to increase, indicative of a much more shortened standing-wave wavelength. With increasing rf power, the secondary density peak shift toward the radial edge, namely, the standing-wave wavelength was increased,more » in good qualitative agreement with the previous theory and simulation results. At higher pressures and high frequencies, the rf power was primarily deposited at the periphery of the electrode, due to the fact that the waves were strongly damped as they propagated from the discharge edge into the center.« less

Coaxial cable stripping device facilitates RF cabling fabrication

NASA Technical Reports Server (NTRS)

Hughes, R. S.; Tobias, R. A.

1967-01-01

Coaxial cable stripping device assures clean, right angled shoulder for RF cable connector fabrication. This method requires minimal skill and creates a low voltage standing wave ratio and mechanical stability in the interconnecting RF Cables.

Design and experiments of RF transverse focusing in S-Band, 1 MeV standing wave linac

NASA Astrophysics Data System (ADS)

Mondal, J.; Chandan, Shiv; Parashar, S.; Bhattacharjee, D.; Tillu, A. R.; Tiwari, R.; Jayapraksh, D.; Yadav, V.; Banerjee, S.; Choudhury, N.; Ghodke, S. R.; Dixit, K. P.; Nimje, V. T.

2015-09-01

S-Band standing wave (SW) linacs in the range of 1-10 MeV have many potential industrial applications world wide. In order to mitigate the industrial requirement it is required to reduce the overall size and weight of the system. On this context a 2856 M Hz, 1 Me V, bi-periodic on axis coupled self transverse focused SW linac has been designed and tested. The RF phase focusing is achieved by introducing an asymmetric field distribution in the first cell of the 1 MeV linac. The pulsed electron beam of 40 keV, 650 mA and 5 μs duration is injected from a LaB6 thermionic gun. This paper presents the structure design, beam dynamics simulation, fabrication and experimental results of the 1 MeV auto-focusing SW linac.

Characterizing the Performance of the Princeton Advanced Test Stand Ion Source

NASA Astrophysics Data System (ADS)

Stepanov, A.; Gilson, E. P.; Grisham, L.; Kaganovich, I.; Davidson, R. C.

2012-10-01

The Princeton Advanced Test Stand (PATS) is a compact experimental facility for studying the physics of intense beam-plasma interactions relevant to the Neutralized Drift Compression Experiment - II (NDCX-II). The PATS facility consists of a multicusp RF ion source mounted on a 2 m-long vacuum chamber with numerous ports for diagnostic access. Ar+ beams are extracted from the source plasma with three-electrode (accel-decel) extraction optics. The RF power and extraction voltage (30 - 100 kV) are pulsed to produce 100 μsec duration beams at 0.5 Hz with excellent shot-to-shot repeatability. Diagnostics include Faraday cups, a double-slit emittance scanner, and scintillator imaging. This work reports measurements of beam parameters for a range of beam energies (30 - 50 keV) and currents to characterize the behavior of the ion source and extraction optics. Emittance scanner data is used to calculate the beam trace-space distribution and corresponding transverse emittance. If the plasma density is changing during a beam pulse, time-resolved emittance scanner data has been taken to study the corresponding evolution of the beam trace-space distribution.

Development of new S-band RF window for stable high-power operation in linear accelerator RF system

NASA Astrophysics Data System (ADS)

Joo, Youngdo; Lee, Byung-Joon; Kim, Seung-Hwan; Kong, Hyung-Sup; Hwang, Woonha; Roh, Sungjoo; Ryu, Jiwan

2017-09-01

For stable high-power operation, a new RF window is developed in the S-band linear accelerator (Linac) RF systems of the Pohang Light Source-II (PLS-II) and the Pohang Accelerator Laboratory X-ray Free-Electron Laser (PAL-XFEL). The new RF window is designed to mitigate the strength of the electric field at the ceramic disk and also at the waveguide-cavity coupling structure of the conventional RF window. By replacing the pill-box type cavity in the conventional RF window with an overmoded cavity, the electric field component perpendicular to the ceramic disk that caused most of the multipacting breakdowns in the ceramic disk was reduced by an order of magnitude. The reduced electric field at the ceramic disk eliminated the Ti-N coating process on the ceramic surface in the fabrication procedure of the new RF window, preventing the incomplete coating from spoiling the RF transmission and lowering the fabrication cost. The overmoded cavity was coupled with input and output waveguides through dual side-wall coupling irises to reduce the electric field strength at the waveguide-cavity coupling structure and the possibility of mode competitions in the overmoded cavity. A prototype of the new RF window was fabricated and fully tested with the Klystron peak input power, pulse duration and pulse repetition rate of 75 MW, 4.5 μs and 10 Hz, respectively, at the high-power test stand. The first mass-produced new RF window installed in the PLS-II Linac is running in normal operation mode. No fault is reported to date. Plans are being made to install the new RF window to all S-band accelerator RF modules of the PLS-II and PAL-XFEL Linacs. This new RF window may be applied to the output windows of S-band power sources like Klystron as wells as the waveguide windows of accelerator facilities which operate in S-band.

Micromachined sensor for stress measurement and micromechanical study of free-standing thin films for MEMS applications

NASA Astrophysics Data System (ADS)

Zhang, Ping

Microelectromechanical systems (MEMS) have a wide range of applications. In the field of wireless and microwave technology, considerable attention has been given to the development and integration of MEMS-based RF (radio frequency) components. An RF MEMS switch requires low insertion loss, high isolation, and low actuation voltage - electrical aspects that have been extensively studied. The mechanical requirements of the switch, such as low sensitivity to built-in stress and high reliability, greatly depend on the micromechanical properties of the switch materials, and have not been thoroughly explored. RF MEMS switches are typically in the form of a free-standing thin film structure. Large stress gradients and across-wafer stress variations developed during fabrication severely degrade their electrical performance. A micromachined stress measurement sensor has been developed that can potentially be employed for in-situ monitoring of stress evolution and stress variation. The sensors were micromachined using five masks on two wafer levels, each measuring 5x3x1 mm. They function by means of an electron tunneling mechanism, where a 2x2 mm silicon nitride membrane elastically deflects under an applied deflection voltage via an external feedback circuitry. For the current design, the sensors are capable of measuring tensile stresses up to the GPa range under deflection voltages of 50--100 V. Sensor functionality was studied by finite element modeling and a theoretical analysis of square membrane deflection. While the mechanical properties of thin films on substrates have been extensively studied, studies of free-standing thin films have been limited due to the practical difficulties in sample handling and testing. Free-standing Al and Al-Ti thin films specimens have been successfully fabricated and microtensile and stress relaxation tests have been performed using a custom-designed micromechanical testing apparatus. A dedicated TEM (transmission electron microscopy) sample preparation technique allows the investigation of the microstructures of these thin films both before and after mechanical testing to correlate the microstructural findings with the mechanical behavior. Major studies include grain boundary strengthening in pure Al, plastic deformation in pure Al by inhomogeneous deformation and localized grain thinning, solid solution and precipitate strengthening in Al-Ti alloys, and stress relaxation of Al and Al-Ti.

Commercialization of an S-band standing-wave electron accelerator for industrial applications

NASA Astrophysics Data System (ADS)

Moon, Jin-Hyeok; Kwak, Gyeong-Il; Han, Jae-Ik; Lee, Gyu-Baek; Jeon, Seong-Hwan; Kim, Jae-Young; Hwang, Cheol-Bin; Lee, Gi-Yong; Kim, Young-Man; Park, Sung-Ju

2016-09-01

An electron accelerator system has been developed for use in industrial, as well as possible medical, applications. Based on our experiences achieved during prototype system development and various electron beam acceleration tests, we have built a stable and compact system for sales purposes. We have integrated a self-developed accelerating cavity, an E-gun pulse driver, a radio-frequency (RF) power system, a vacuum system, a cooling system, etc. into a frame with a size of 1800 × 1000 × 1500 mm3. The accelerating structure is a side-coupled standing-wave type operating in the π/2 mode (tuned to~3 GHz). The RF power is provided by using a magnetron driven by a solid-state modulator. The electron gun is a triode type with a dispenser cathode (diameter of 11 mm). The system is capable of delivering a maximum 900-W average electron beam power with tight focusing at the target. Until now, we have performed various electron beam tests and X-ray beam tests after having built the system, have completed the beam assessment for commercializations, and have been preparing full-fledged sales activity. This article reports on our system development processes and on some of our early test results for commercializations.

Standing Helicon Wave Induced by a Rapidly Bent Magnetic Field in Plasmas.

PubMed

Takahashi, Kazunori; Takayama, Sho; Komuro, Atsushi; Ando, Akira

2016-04-01

An electron energy probability function and a rf magnetic field are measured in a rf hydrogen helicon source, where axial and transverse static magnetic fields are applied to the source by solenoids and to the diffusion chamber by filter magnets, respectively. It is demonstrated that the helicon wave is reflected by the rapidly bent magnetic field and the resultant standing wave heats the electrons between the source and the magnetic filter, while the electron cooling effect by the magnetic filter is maintained. It is interpreted that the standing wave is generated by the presence of a spatially localized change of a refractive index.

Standing Helicon Wave Induced by a Rapidly Bent Magnetic Field in Plasmas

NASA Astrophysics Data System (ADS)

Takahashi, Kazunori; Takayama, Sho; Komuro, Atsushi; Ando, Akira

2016-04-01

An electron energy probability function and a rf magnetic field are measured in a rf hydrogen helicon source, where axial and transverse static magnetic fields are applied to the source by solenoids and to the diffusion chamber by filter magnets, respectively. It is demonstrated that the helicon wave is reflected by the rapidly bent magnetic field and the resultant standing wave heats the electrons between the source and the magnetic filter, while the electron cooling effect by the magnetic filter is maintained. It is interpreted that the standing wave is generated by the presence of a spatially localized change of a refractive index.

Development of the PEFP's beam line BPM

NASA Astrophysics Data System (ADS)

Ryu, Jin-Yeong; Kwon, Hyeok-Jung; Jang, Ji-Ho; Kim, Han-Sung; Seol, Kyung-Tae; Cho, Yong-Sub

2013-01-01

The Proton Engineering Frontier Project (PEFP) has 20-MeV and 100-MeV beam lines to supply proton beams to users. A stripline-type Beam Position Monitor (BPM) was designed and fabricated in order to measure the beam's position in the beam line. The RF properties of the BPM were measured and compared with the simulation. After the sensitivity of the BPM at a test stand had been obtained, we performed a beam test in a test beam line of the PEFP 20-MeV proton linac.

Ion extraction from a saddle antenna RF surface plasma source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dudnikov, V., E-mail: vadim@muonsinc.com; Johnson, R. P.; Han, B.

Existing RF Surface Plasma Sources (SPS) for accelerators have specific efficiencies for H{sup +} and H{sup −} ion generation around 3 to 5 mA/cm{sup 2} per kW, where about 50 kW of RF power is typically needed for 50 mA beam current production. The Saddle Antenna (SA) SPS described here was developed to improve H{sup −} ion production efficiency and SPS reliability and availability. At low RF power, the efficiency of positive ion generation in the plasma has been improved to 200 mA/cm{sup 2} per kW of RF power at 13.56 MHz. Initial cesiation of the SPS was performed bymore » heating cesium chromate cartridges by discharge as was done in the very first versions of the SPS. A small oven to decompose cesium compounds and alloys was developed and tested. After cesiation, the current of negative ions to the collector was increased from 1 mA to 10 mA with RF power ∼1.5 kW in the plasma (6 mm diameter emission aperture) and up to 30 mA with ∼4 kW RF power in the plasma and 250 Gauss longitudinal magnetic field. The ratio of electron current to negative ion current was improved from 30 to 2. Stable generation of H{sup −} beam without intensity degradation was demonstrated in the AlN discharge chamber for a long time at high discharge power in an RF SPS with an external antenna. Continuous wave (CW) operation of the SA SPS has been tested on the small test stand. The general design of the CW SA SPS is based on the pulsed version. Some modifications were made to improve the cooling and cesiation stability. The extracted collector current can be increased significantly by optimizing the longitudinal magnetic field in the discharge chamber. CW operation with negative ion extraction was tested with RF power up to 1.8 kW from the generator (∼1.2 kW in the plasma) with production up to Ic=7 mA. Long term operation was tested with 1.2 kW from the RF generator (∼0.8 kW in the plasma) with production of Ic=5 mA, Iex ∼15 mA (Uex=8 kV, Uc=14 kV)« less

Ion extraction from a saddle antenna RF surface plasma source

NASA Astrophysics Data System (ADS)

Dudnikov, V.; Johnson, R. P.; Han, B.; Murray, S.; Pennisi, T.; Piller, C.; Santana, M.; Stockli, M.; Welton, R.; Breitschopf, J.; Dudnikova, G.

2015-04-01

Existing RF Surface Plasma Sources (SPS) for accelerators have specific efficiencies for H+ and H- ion generation around 3 to 5 mA/cm2 per kW, where about 50 kW of RF power is typically needed for 50 mA beam current production. The Saddle Antenna (SA) SPS described here was developed to improve H- ion production efficiency and SPS reliability and availability. At low RF power, the efficiency of positive ion generation in the plasma has been improved to 200 mA/cm2 per kW of RF power at 13.56 MHz. Initial cesiation of the SPS was performed by heating cesium chromate cartridges by discharge as was done in the very first versions of the SPS. A small oven to decompose cesium compounds and alloys was developed and tested. After cesiation, the current of negative ions to the collector was increased from 1 mA to 10 mA with RF power ˜1.5 kW in the plasma (6 mm diameter emission aperture) and up to 30 mA with ˜4 kW RF power in the plasma and 250 Gauss longitudinal magnetic field. The ratio of electron current to negative ion current was improved from 30 to 2. Stable generation of H- beam without intensity degradation was demonstrated in the AlN discharge chamber for a long time at high discharge power in an RF SPS with an external antenna. Continuous wave (CW) operation of the SA SPS has been tested on the small test stand. The general design of the CW SA SPS is based on the pulsed version. Some modifications were made to improve the cooling and cesiation stability. The extracted collector current can be increased significantly by optimizing the longitudinal magnetic field in the discharge chamber. CW operation with negative ion extraction was tested with RF power up to 1.8 kW from the generator (˜1.2 kW in the plasma) with production up to Ic=7 mA. Long term operation was tested with 1.2 kW from the RF generator (˜0.8 kW in the plasma) with production of Ic=5 mA, Iex ˜15 mA (Uex=8 kV, Uc=14 kV).

Impact of one's own mobile phone in stand-by mode on personal radiofrequency electromagnetic field exposure.

PubMed

Urbinello, Damiano; Röösli, Martin

2013-01-01

When moving around, mobile phones in stand-by mode periodically send data about their positions. The aim of this paper is to evaluate how personal radiofrequency electromagnetic field (RF-EMF) measurements are affected by such location updates. Exposure from a mobile phone handset (uplink) was measured during commuting by using a randomized cross-over study with three different scenarios: disabled mobile phone (reference), an activated dual-band phone and a quad-band phone. In the reference scenario, uplink exposure was highest during train rides (1.19 mW/m(2)) and lowest during car rides in rural areas (0.001 mW/m(2)). In public transports, the impact of one's own mobile phone on personal RF-EMF measurements was not observable because of high background uplink radiation from other people's mobile phone. In a car, uplink exposure with an activated phone was orders of magnitude higher compared with the reference scenario. This study demonstrates that personal RF-EMF exposure is affected by one's own mobile phone in stand-by mode because of its regular location update. Further dosimetric studies should quantify the contribution of location updates to the total RF-EMF exposure in order to clarify whether the duration of mobile phone use, the most common exposure surrogate in the epidemiological RF-EMF research, is actually an adequate exposure proxy.

Effect of fatigue on force production and force application technique during repeated sprints.

PubMed

Morin, Jean-Benoit; Samozino, Pierre; Edouard, Pascal; Tomazin, Katja

2011-10-13

We investigated the changes in the technical ability of force application/orientation against the ground vs. the physical capability of total force production after a multiple-set repeated sprints series. Twelve male physical education students familiar with sprint running performed four sets of five 6-s sprints (24s of passive rest between sprints, 3min between sets). Sprints were performed from a standing start on an instrumented treadmill, allowing the computation of vertical (F(V)), net horizontal (F(H)) and total (F(Tot)) ground reaction forces for each step. Furthermore, the ratio of forces was calculated as RF=F(H)F(Tot)(-1), and the index of force application technique (D(RF)) representing the decrement in RF with increase in speed was computed as the slope of the linear RF-speed relationship. Changes between pre- (first two sprints) and post-fatigue (last two sprints) were tested using paired t-tests. Performance decreased significantly (e.g. top speed decreased by 15.7±5.4%; P<0.001), and all the mechanical variables tested significantly changed. F(H) showed the largest decrease, compared to F(V) and F(Tot). D(RF) significantly decreased (P<0.001, effect size=1.20), and the individual magnitudes of change of D(RF) were significantly more important than those of F(Tot) (19.2±20.9 vs. 5.81±5.76%, respectively; P<0.01). During a multiple-set repeated sprint series, both the total force production capability and the technical ability to apply force effectively against the ground are altered, the latter to a larger extent than the former. Copyright © 2011 Elsevier Ltd. All rights reserved.

Center conductor diagnostic for multipactor detection in inaccessible geometries.

PubMed

Chaplin, Vernon H; Hubble, Aimee A; Clements, Kathryn A; Graves, Timothy P

2017-01-01

Electron collecting current probes are the most reliable diagnostic of multipactor and radiofrequency (RF) ionization breakdown; however, stand-alone probes can only be used in test setups where the breakdown region is physically accessible. This paper describes techniques for measuring multipactor current directly on the center conductor of a coaxial RF device (or more generally, on the signal line in any two-conductor RF system) enabling global multipactor detection with improved sensitivity compared to other common diagnostics such as phase null, third harmonic, and reflected power. The center conductor diagnostic may be AC coupled for use in systems with a low DC impedance between the center conductor and ground. The effect of DC bias on the breakdown threshold was studied: in coaxial geometry, the change in threshold was <1 dB for positive biases satisfying V DC /V RF0 <0.8, where V RF0 is the RF voltage amplitude at the unperturbed breakdown threshold. In parallel plate geometry, setting V DC /V RF0 <0.2 was necessary to avoid altering the threshold by more than 1 dB. In most cases, the center conductor diagnostic functions effectively with no bias at all-this is the preferred implementation, but biases in the range V DC =0-10V may be applied if necessary. The polarity of the detected current signal may be positive or negative depending on whether there is net electron collection or emission globally.

High Peak Power Test and Evaluation of S-band Waveguide Switches

NASA Astrophysics Data System (ADS)

Nassiri, A.; Grelick, A.; Kustom, R. L.; White, M.

1997-05-01

The injector and source of particles for the Advanced Photon Source is a 2856-MHz S-band electron-positron linear accelerator (linac) which produces electrons with energies up to 650 MeV or positrons with energies up to 450 MeV. To improve the linac rf system availability, an additional modulator-klystron subsystem is being constructed to provide a switchable hot spare unit for each of the five exsisting S-band transmitters. The switching of the transmitters will require the use of SF6-pressurized S-band waveguide switches at a peak operating power of 35 MW. Such rf switches have been successfully operated at other accelerator facilities but at lower peak powers. A test stand has been set up at the Stanford Linear Accelerator Center (SLAC) Klystron Factory to conduct tests comparing the power handling characteristics of two WR-284 and one WR-340 switches. Test results are presented and their implications for the design of the switching system are discussed.

Muscular Activity and Fatigue in Lower-Limb and Trunk Muscles during Different Sit-To-Stand Tests.

PubMed

Roldán-Jiménez, Cristina; Bennett, Paul; Cuesta-Vargas, Antonio I

2015-01-01

Sit-to-stand (STS) tests measure the ability to get up from a chair, reproducing an important component of daily living activity. As this functional task is essential for human independence, STS performance has been studied in the past decades using several methods, including electromyography. The aim of this study was to measure muscular activity and fatigue during different repetitions and speeds of STS tasks using surface electromyography in lower-limb and trunk muscles. This cross-sectional study recruited 30 healthy young adults. Average muscle activation, percentage of maximum voluntary contraction, muscle involvement in motion and fatigue were measured using surface electrodes placed on the medial gastrocnemius (MG), biceps femoris (BF), vastus medialis of the quadriceps (QM), the abdominal rectus (AR), erector spinae (ES), rectus femoris (RF), soleus (SO) and the tibialis anterior (TA). Five-repetition STS, 10-repetition STS and 30-second STS variants were performed. MG, BF, QM, ES and RF muscles showed differences in muscle activation, while QM, AR and ES muscles showed significant differences in MVC percentage. Also, significant differences in fatigue were found in QM muscle between different STS tests. There was no statistically significant fatigue in the BF, MG and SO muscles of the leg although there appeared to be a trend of increasing fatigue. These results could be useful in describing the functional movements of the STS test used in rehabilitation programs, notwithstanding that they were measured in healthy young subjects.

Planned Experiments on the Princeton Advanced Test Stand

NASA Astrophysics Data System (ADS)

Stepanov, A.; Gilson, E. P.; Grisham, L.; Kaganovich, I.; Davidson, R. C.

2010-11-01

The Princeton Advanced Test Stand (PATS) device is an experimental facility based on the STS-100 high voltage test stand transferred from LBNL. It consists of a multicusp RF ion source, a pulsed extraction system capable of forming high-perveance 100keV ion beams, and a large six-foot-long vacuum with convenient access for beam diagnostics. This results in a flexible system for studying high perveance ion beams relevant to NDCX-I/II, including experiments on beam neutralization by ferroelectric plasma sources (FEPS) being developed at PPPL. Research on PATS will concern the basic physics of beam-plasma interactions, such as the effects of volume neutralization on beam emittance, as well as optimizing technology of the FEPS. PATS combines the advantage of an ion beam source and a large-volume plasma source in a chamber with ample access for diagnostics, resulting in a robust setup for investigating and improving relevant aspects of neutralized drift. There are also plans for running the ion source with strongly electro-negative gases such as chlorine, making it possible to extract positive or negative ion beams.

Status and operation of the Linac4 ion source prototypes

NASA Astrophysics Data System (ADS)

Lettry, J.; Aguglia, D.; Andersson, P.; Bertolo, S.; Butterworth, A.; Coutron, Y.; Dallocchio, A.; Chaudet, E.; Gil-Flores, J.; Guida, R.; Hansen, J.; Hatayama, A.; Koszar, I.; Mahner, E.; Mastrostefano, C.; Mathot, S.; Mattei, S.; Midttun, Ø.; Moyret, P.; Nisbet, D.; Nishida, K.; O'Neil, M.; Ohta, M.; Paoluzzi, M.; Pasquino, C.; Pereira, H.; Rochez, J.; Sanchez Alvarez, J.; Sanchez Arias, J.; Scrivens, R.; Shibata, T.; Steyaert, D.; Thaus, N.; Yamamoto, T.

2014-02-01

CERN's Linac4 45 kV H- ion sources prototypes are installed at a dedicated ion source test stand and in the Linac4 tunnel. The operation of the pulsed hydrogen injection, RF sustained plasma, and pulsed high voltages are described. The first experimental results of two prototypes relying on 2 MHz RF-plasma heating are presented. The plasma is ignited via capacitive coupling, and sustained by inductive coupling. The light emitted from the plasma is collected by viewports pointing to the plasma chamber wall in the middle of the RF solenoid and to the plasma chamber axis. Preliminary measurements of optical emission spectroscopy and photometry of the plasma have been performed. The design of a cesiated ion source is presented. The volume source has produced a 45 keV H- beam of 16-22 mA which has successfully been used for the commissioning of the Low Energy Beam Transport (LEBT), Radio Frequency Quadrupole (RFQ) accelerator, and chopper of Linac4.

Adjustment and Validation of the Mathematical Prediction Model for Sweat Rate, Heart Rate and Body Temperature under Outdoor Conditions

DTIC Science & Technology

1986-11-01

Predicting rectal temperature response to work environment and clothing. J. Pppl . PhysioL. 32: 812-822, 1972. 3. Givoni B., Goldman RF: Predicting...heart rote response to work, environment and clothing. J. PppL . PhysioL. 34: 201-204, 1973. 4. Givoni B., Goldman RF: Predicting effects of heat...expenditure with loads while standing or walking very slowly. J. Pppl . Physlol. 43: 477-581, 1877. G. Shapiro Y., Pandolf KB., Breckenridge JR., Goldman RF

Development Status of Ion Source at J-PARC Linac Test Stand

NASA Astrophysics Data System (ADS)

Yamazaki, S.; Takagi, A.; Ikegami, K.; Ohkoshi, K.; Ueno, A.; Koizumi, I.; Oguri, H.

The Japan Proton Accelerator Research Complex (J-PARC) linac power upgrade program is now in progress in parallel with user operation. To realize a nominal performance of 1 MW at 3 GeV Rapid Cycling Synchrotron and 0.75 MW at the Main Ring synchrotron, we need to upgrade the peak beam current (50 mA) of the linac. For the upgrade program, we are testing a new front-end system, which comprises a cesiated RF-driven H- ion source and a new radio -frequency quadrupole linac (RFQ). The H- ion source was developed to satisfy the J-PARC upgrade requirements of an H- ion-beam current of 60 mA and a lifetime of more than 50 days. On February 6, 2014, the first 50 mA H- beams were accelerated by the RFQ during a beam test. To demonstrate the performance of the ion source before its installation in the summer of 2014, we tested the long-term stability through continuous beam operation, which included estimating the lifetime of the RF antenna and evaluating the cesium consumption.

Cleaning techniques for intense ion beam sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Menge, P.R.; Cuneo, M.E.; Bailey, J.E.

Generation of high power lithium ion beams on the SABRE (1TW) and PBFA-X (20 TW) accelerators have been limited by the parallel acceleration of contaminant ions. during the beam pulse lithium is replaced by protons and carbon ions. This replacement is accompanied by rapid impedance decay of the diode. The contaminant hydrogen and carbon is believed to originate from impurity molecules on the surface and in the bulk of the lithium ion source and its substrate material. Cleaning techniques designed to remove hydrocarbons from the ion source have been employed with some success in test stand experiments and on SABRE.more » The test stand experiments have shown that a lithium fluoride (LiF) ion source film can accrue dozens of hydrocarbon monolayers on its surface while sitting in vacuum. Application of 13.5 MHz RF discharge cleaning with 90% Ar/10% O{sub 2} can significantly reduce the surface hydrocarbon layers on the LiF film. On SABRE, combinations of RF discharge cleaning, anode heating, layering gold between the source film (LiF) and its substrate, and cryogenic cathode cooling produced an increase by a factor of 1.5--2 in the quantity of high energy lithium in the ion beam. A corresponding decrease in protons and carbon ions was also observed. Cleaning experiments on PBFA-X are underway. New designs of contamination resistant films and Li ion sources are currently being investigated.« less

Maintenance and operation procedure, and feedback controls of the J-PARC RF-driven H{sup −} ion source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ueno, A., E-mail: akira.ueno@j-parc.jp; Ohkoshi, K.; Ikegami, K.

2015-04-08

In order to satisfy the Japan Proton Accelerator Research Complex (J-PARC) second stage requirements of an H{sup −} ion beam of 60mA within normalized emittances of 1.5πmm•mrad both horizontally and vertically, a flat top beam duty factor of 1.25% (500μs×25Hz) and a life-time of longer than 1month, the J-PARC cesiated RF-driven H{sup −} ion source was developed by using an internal-antenna developed at the Spallation Neutron Source (SNS). The maintenance and operation procedure to minimize the plasma chamber (PCH) replacement time on the beam line, which is very important to maximize the J-PARC beam time especially for an antenna failure,more » is presented in this paper. The PCH preserved by filling argon (Ar) gas inside after pre-conditioning including pre-cesiation to produce the required beam at a test-stand successfully produced the required beam on the beam line with slight addition of cesium (Cs). The methods of the feedback controls of a 2MHz-RF-matching, an H{sup −} ion beam intensity and the addition of Cs are also presented. The RF-matching feedback by using two vacuum variable capacitors (VVCs) and RF-frequency shift produced the almost perfect matching with negligibly small reflected RF-power. The H{sup −} ion beam intensity was controlled within errors of ±0.1mA by the RF-power feedback. The amount of Cs was also controlled by remotely opening a Cs-valve to keep the RF-power lower than a settled value.« less

Test results for the 201.25 MHZ tetrode power amplifier at LANSCE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lyles, J. T.; Archuletta, S.; Davis, J. L.

2004-01-01

A new RF amplifier has been constructed for use as the intermediate power amplifier stage for the 201.25 MHz Alvarez DTL at the Los Alamos Neutron Science Center (LANSCE). It is part of a larger upgrade to replace the entire RF plant with a new generation of components. The new RF power system under development will enable increased peak power with higher duty factor. The first tank requires over 400 kW of RF power. This can be satisfied using the TH781 tetrode in a THALES cavity amplifier. The same stage will be also used to drive a TH628 Diacrode(reg. sign)more » final power amplifier for each of the three remaining DTL tanks. In this application, it will only be required to deliver approximately 150 kW of peak power. Details of the system design, layout for DTL 1, and test results will be presented. The Thales cavity amplifier and TH78I tetrode have been tested for two upcoming requirements at LANSCE. As an IPA to drive a future TH628 Diacrode(reg. sign) FPA with 120-150 kW, the amplifier provided over 16 dB power gain with 50% efficiency or better. As a stand-alone FPA to drive a 5 MeV Alvarez DTI, tank, the amplifier provided 13.5 dB power gain with 50% efficiency or better. It can also be used to drive a 200 MHz RFQ in the future. Power supplies, driver amplifier and coaxial circulators are being specified for the complete installation.« less

Quasi-free-standing bilayer epitaxial graphene field-effect transistors on 4H-SiC (0001) substrates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, C.; Li, J.; Song, X. B.

2016-01-04

Quasi-free-standing epitaxial graphene grown on wide band gap semiconductor SiC demonstrates high carrier mobility and good material uniformity, which make it promising for graphene-based electronic devices. In this work, quasi-free-standing bilayer epitaxial graphene is prepared and its transistors with gate lengths of 100 nm and 200 nm are fabricated and characterized. The 100 nm gate length graphene transistor shows improved DC and RF performances including a maximum current density I{sub ds} of 4.2 A/mm, and a peak transconductance g{sub m} of 2880 mS/mm. Intrinsic current-gain cutoff frequency f{sub T} of 407 GHz is obtained. The exciting DC and RF performances obtained in the quasi-free-standingmore » bilayer epitaxial graphene transistor show the great application potential of this material system.« less

Standing helicon induced by a rapidly bent magnetic field in plasmas

NASA Astrophysics Data System (ADS)

Takahashi, Kazunori; Takayama, Sho; Komuro, Atsushi; Ando, Akira; Plasma physics Team

2016-09-01

An electron energy probability function and an rf magnetic field are measured in an rf hydrogen helicon source, where axial and transverse static magnetic fields are applied to the source by solenoids and to the diffusion chamber by filter magnets, respectively. It is demonstrated that the helicon wave is reflected by the rapidly bent magnetic field and the resultant standing wave heats the electrons between the source and the magnetic filter, while the electron cooling effect by the magnetic filter is maintained. It is interpreted that the standing wave is generated by the presence of spatially localized change of a refractive index. The application to the hydrogen negative ion source used for the neutral beam injection system for fusion plasma heating is discussed. This work is partially supported by grant-in-aid for scientific research (16H04084 and 26247096) from the Japan Society for the Promotion of Science.

Integrated Advanced Microwave Sounding Unit-A (AMSU-A). Performance Verification Report: EOS AMSU-A1 and AMSU-A2 Receiver Assemblies

NASA Technical Reports Server (NTRS)

Ma, Y.

1995-01-01

The AMSU-A receiver subsystem comprises two separated receiver assemblies; AMSU-A1 and AMSU-A2 (P/N 1356441-1). The AMSU-A1 receiver contains 13 channels and the AMSU-A2 receiver 2 channels. The AMSU-A1 receiver assembly is further divided into two parts; AMSU-A1-1 (P/N 1356429-1) and AMSU-A1-2 (P/N 1356409-1), which contain 9 and 4 channels, respectively. The receiver assemblies are highlighted and illustrate the functional block diagrams of the AMSU-A1 and AMSU-A2 systems. The AMSU-A receiver subsystem stands in between the antenna and signal processing subsystems of the AMSU-A instrument and comprises the RF and IF components from isolators to attenuators. It receives the RF signals from the antenna subsystem, down-converts the RF signals to IF signals, amplifies and defines the IF signals to proper power level and frequency bandwidth as specified for each channel, and inputs the IF signals to the signal processing subsystem. This test report presents the test data of the EOS AMSU-A Flight Model No. 1 (FM-1) receiver subsystem. The tests are performed per the Acceptance Test Procedure for the AMSU-A Receiver Subsystem, AE-26002/6A. The functional performance tests are conducted either at the component or subsystem level. While the component-level tests are performed over the entire operating temperature range predicted by thermal analysis, the subsystem-level tests are conducted at ambient temperature only.

RF-MEMS for future mobile applications: experimental verification of a reconfigurable 8-bit power attenuator up to 110 GHz

NASA Astrophysics Data System (ADS)

Iannacci, J.; Tschoban, C.

2017-04-01

RF-MEMS technology is proposed as a key enabling solution for realising the high-performance and highly reconfigurable passive components that future communication standards will demand. In this work, we present, test and discuss a novel design concept for an 8-bit reconfigurable power attenuator, manufactured using the RF-MEMS technology available at the CMM-FBK, in Italy. The device features electrostatically controlled MEMS ohmic switches in order to select/deselect the resistive loads (both in series and shunt configuration) that attenuate the RF signal, and comprises eight cascaded stages (i.e. 8-bit), thus implementing 256 different network configurations. The fabricated samples are measured (S-parameters) from 10 MHz to 110 GHz in a wide range of different configurations, and modelled/simulated with Ansys HFSS. The device exhibits attenuation levels (S21) in the range from  -10 dB to  -60 dB, up to 110 GHz. In particular, S21 shows flatness from 15 dB down to 3-5 dB and from 10 MHz to 50 GHz, as well as fewer linear traces up to 110 GHz. A comprehensive discussion is developed regarding the voltage standing wave ratio, which is employed as a quality indicator for the attenuation levels. The margins of improvement at design level which are needed to overcome the limitations of the presented RF-MEMS device are also discussed.

Combined effect of pulse density and grid cell size on predicting and mapping aboveground carbon in fast-growing Eucalyptus forest plantation using airborne LiDAR data.

PubMed

Silva, Carlos Alberto; Hudak, Andrew Thomas; Klauberg, Carine; Vierling, Lee Alexandre; Gonzalez-Benecke, Carlos; de Padua Chaves Carvalho, Samuel; Rodriguez, Luiz Carlos Estraviz; Cardil, Adrián

2017-12-01

LiDAR remote sensing is a rapidly evolving technology for quantifying a variety of forest attributes, including aboveground carbon (AGC). Pulse density influences the acquisition cost of LiDAR, and grid cell size influences AGC prediction using plot-based methods; however, little work has evaluated the effects of LiDAR pulse density and cell size for predicting and mapping AGC in fast-growing Eucalyptus forest plantations. The aim of this study was to evaluate the effect of LiDAR pulse density and grid cell size on AGC prediction accuracy at plot and stand-levels using airborne LiDAR and field data. We used the Random Forest (RF) machine learning algorithm to model AGC using LiDAR-derived metrics from LiDAR collections of 5 and 10 pulses m -2 (RF5 and RF10) and grid cell sizes of 5, 10, 15 and 20 m. The results show that LiDAR pulse density of 5 pulses m -2 provides metrics with similar prediction accuracy for AGC as when using a dataset with 10 pulses m -2 in these fast-growing plantations. Relative root mean square errors (RMSEs) for the RF5 and RF10 were 6.14 and 6.01%, respectively. Equivalence tests showed that the predicted AGC from the training and validation models were equivalent to the observed AGC measurements. The grid cell sizes for mapping ranging from 5 to 20 also did not significantly affect the prediction accuracy of AGC at stand level in this system. LiDAR measurements can be used to predict and map AGC across variable-age Eucalyptus plantations with adequate levels of precision and accuracy using 5 pulses m -2 and a grid cell size of 5 m. The promising results for AGC modeling in this study will allow for greater confidence in comparing AGC estimates with varying LiDAR sampling densities for Eucalyptus plantations and assist in decision making towards more cost effective and efficient forest inventory.

The RF Probe: providing space situational awareness through broad-spectrum detection and characterization

NASA Astrophysics Data System (ADS)

Zenick, Raymond; Kohlhepp, Kimberly; Partch, Russell

2004-09-01

AeroAstro's patented RF Probe is a system designed to address the needs of spacecraft developers and operators interested in measuring and analyzing near-field RF emissions emanating from a nearby spacecraft of interest. The RF Probe consists of an intelligent spectrum analyzer with digital signal processing capabilities combined with a calibrated, wide-bandwidth antenna and RF front end that covers the 50 kHz to 18 GHz spectrum. It is capable of acquiring signal level and signal vector information, classifying signals, assessing the quality of a satellite"s transponders, and characterizing near-field electromagnetic emissions. The RF Probe is intended for either incorporation as part of a suite of spacecraft sensors, or as a stand-alone sensor on spacecraft or other platforms such as Unmanned Aerial Vehicles (UAVs). The RF Probe was initially conceived as a tool to detect and aid in diagnosis of malfunctions in a spacecraft of interest. However, the utility of the RF Probe goes far beyond this initial concept, spanning a wide range of military applications. Most importantly, the RF Probe can provide space situational awareness for critical on-orbit assets by detecting externally induced RF fields, aiding in protection against potentially devastating attacks.

Ultra-High Accelerating Gradients in Radio-Frequency Cryogenic Copper Structures

NASA Astrophysics Data System (ADS)

Cahill, Alexander David

Normal conducting radio-frequency (rf) particle accelerators have many applications, including colliders for high energy physics, high-intensity synchrotron light sources, non-destructive testing for security, and medical radiation therapy. In these applications, the accelerating gradient is an important parameter. Specifically for high energy physics, increasing the accelerating gradient extends the potential energy reach and is viewed as a way to mitigate their considerable cost. Furthermore, a gradient increase will enable for more compact and thus accessible free electron lasers (FELs). The major factor limiting larger accelerating gradients is vacuum rf breakdown. Basic physics of this phenomenon has been extensively studied over the last few decades. During which, the occurrence of rf breakdowns was shown to be probabilistic, and can be characterized by a breakdown rate. The current consensus is that vacuum rf breakdowns are caused by movements of crystal defects induced by periodic mechanical stress. The stress may be caused by pulsed surface heating and large electric fields. A compelling piece of evidence that supports this hypothesis is that accelerating structures constructed from harder materials exhibit larger accelerating gradients for similar breakdown rates. One possible method to increase sustained electric fields in copper cavities is to cool them to temperatures below 77 K, where the rf surface resistance and coefficient of thermal expansion decrease, while the yield strength (which correlates with hardness) and thermal conductivity increase. These changes in material properties at low temperature increases metal hardness and decreases the mechanical stress from exposure to rf electromagnetic fields. To test the validity of the improvement in breakdown rate, experiments were conducted with cryogenic accelerating cavities in the Accelerator Structure Test Area (ASTA) at SLAC National Accelerator Laboratory. A short 11.4 GHz standing wave accelerating structure was conditioned to an accelerating gradient of 250 MV/m at 45 K with 108 rf pulses. At gradients greater than 150 MV/m I observed a degradation in the intrinsic quality factor of the cavity, Q0. I developed a model for the change in Q0 using measured field emission currents and rf signals. I found that the Q 0 degradation is consistent with the rf power being absorbed by strong field emission currents accelerated inside the cavity. I measured rf breakdown rates for 45 K and found 2*10-4/pulse/meter when accounting for any change in Q0. These are the largest accelerating gradients for a structure with similar breakdown rates. The final chapter presents the design of an rf photoinjector electron source that uses the cryogenic normal conducting accelerator technology: the TOPGUN. With this cryogenic rf photoinjector, the beam brightness will increase by over an order of a magnitude when compared to the current photoinjector for the Linac Coherent Light Source (LCLS). When using the TOPGUN as the source for an X-ray Free Electron Laser, the higher brightness would allow for a decrease in the required length of the LCLS undulator by more than a factor of two.

Advances in high gradient normal conducting accelerator structures

DOE PAGES

Simakov, Evgenya Ivanovna; Dolgashev, Valery A.; Tantawi, Sami G.

2018-03-09

Here, this paper reviews the current state-of-the-art in understanding the phenomena of ultra-high vacuum radio-frequency (rf) breakdown in accelerating structures and the efforts to improve stable operation of the structures at accelerating gradients above 100 MV/m. Numerous studies have been conducted recently with the goal of understanding the dependence of the achievable accelerating gradients and breakdown rates on the frequency of operations, the geometry of the structure, material and method of fabrication, and operational temperature. Tests have been conducted with single standing wave accelerator cells as well as with the multi-cell traveling wave structures. Notable theoretical effort was directed atmore » understanding the physical mechanisms of the rf breakdown and its statistical behavior. Finally, the achievements presented in this paper are the result of the large continuous self-sustaining collaboration of multiple research institutions in the United States and worldwide.« less

Advances in high gradient normal conducting accelerator structures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simakov, Evgenya Ivanovna; Dolgashev, Valery A.; Tantawi, Sami G.

Here, this paper reviews the current state-of-the-art in understanding the phenomena of ultra-high vacuum radio-frequency (rf) breakdown in accelerating structures and the efforts to improve stable operation of the structures at accelerating gradients above 100 MV/m. Numerous studies have been conducted recently with the goal of understanding the dependence of the achievable accelerating gradients and breakdown rates on the frequency of operations, the geometry of the structure, material and method of fabrication, and operational temperature. Tests have been conducted with single standing wave accelerator cells as well as with the multi-cell traveling wave structures. Notable theoretical effort was directed atmore » understanding the physical mechanisms of the rf breakdown and its statistical behavior. Finally, the achievements presented in this paper are the result of the large continuous self-sustaining collaboration of multiple research institutions in the United States and worldwide.« less

Progress Toward a Gigawatt-Class Annular Beam Klystron with a Thermionic Electron Gun

NASA Astrophysics Data System (ADS)

Fazio, M.; Carlsten, B.; Farnham, J.; Habiger, K.; Haynes, W.; Myers, J.; Nelson, E.; Smith, J.; Arfin, B.; Haase, A.

2002-08-01

In an effort to reach the gigawatt power level in the microsecond pulse length regime Los Alamos, in collaboration with SLAC, is developing an annular beam klystron (ABK) with a thermionic electron gun. We hope to address the causes of pulse shortening in very high peak power tubes by building a "hard-vacuum" tube in the 10-10 Torr range with a thermionic electron gun producing a constant impedance electron-beam. The ABK has been designed to operate at 5 Hz pulse repetition frequency to allow for RF conditioning. The electron gun has a magnetron injection gun configuration and uses a dispenser cathode running at 1100 degC to produce a 4 kA electron beam at 800 kV. The cathode is designed to run in the temperature-limited mode to help maintain beam stability in the gun. The beam-stick consisting of the electron gun, an input cavity, an idler cavity, and drift tube, and the collector has been designed collaboratively, fabricated at SLAC, then shipped to Los Alamos for testing. On the test stand at Los Alamos a low voltage emission test was performed, but unfortunately as we prepared for high voltage testing a problem with the cathode heater was encountered that prevented the cathode from reaching a high enough temperature for electron emission. A post-mortem examination will be done shortly to determine the exact cause of the heater failure. The RF design has been proceeding and is almost complete. The output cavity presents a challenging design problem in trying to efficiently extract energy from the low impedance beam while maintaining a gap voltage low enough to avoid breakdown and a Q high enough to maintain mode purity. In the next iteration, the ABK will have a new cathode assembly installed along with the remainder of the RF circuit. This paper will discuss the electron gun and the design of the RF circuit along with a report on the status of the work.

Error analysis for intrinsic quality factor measurement in superconducting radio frequency resonators

DOE PAGES

Melnychuk, O.; Grassellino, A.; Romanenko, A.

2014-12-19

In this paper, we discuss error analysis for intrinsic quality factor (Q₀) and accelerating gradient (E acc ) measurements in superconducting radio frequency (SRF) resonators. The analysis is applicable for cavity performance tests that are routinely performed at SRF facilities worldwide. We review the sources of uncertainties along with the assumptions on their correlations and present uncertainty calculations with a more complete procedure for treatment of correlations than in previous publications [T. Powers, in Proceedings of the 12th Workshop on RF Superconductivity, SuP02 (Elsevier, 2005), pp. 24–27]. Applying this approach to cavity data collected at Vertical Test Stand facility atmore » Fermilab, we estimated total uncertainty for both Q₀ and E acc to be at the level of approximately 4% for input coupler coupling parameter β₁ in the [0.5, 2.5] range. Above 2.5 (below 0.5) Q₀ uncertainty increases (decreases) with β₁ whereas E acc uncertainty, in contrast with results in Powers [in Proceedings of the 12th Workshop on RF Superconductivity, SuP02 (Elsevier, 2005), pp. 24–27], is independent of β₁. Overall, our estimated Q₀ uncertainty is approximately half as large as that in Powers [in Proceedings of the 12th Workshop on RF Superconductivity, SuP02 (Elsevier, 2005), pp. 24–27].« less

Center conductor diagnostic for multipactor detection in inaccessible geometries

NASA Astrophysics Data System (ADS)

Chaplin, Vernon H.; Hubble, Aimee A.; Clements, Kathryn A.; Graves, Timothy P.

2017-01-01

Electron collecting current probes are the most reliable diagnostic of multipactor and radiofrequency (RF) ionization breakdown; however, stand-alone probes can only be used in test setups where the breakdown region is physically accessible. This paper describes techniques for measuring multipactor current directly on the center conductor of a coaxial RF device (or more generally, on the signal line in any two-conductor RF system) enabling global multipactor detection with improved sensitivity compared to other common diagnostics such as phase null, third harmonic, and reflected power. The center conductor diagnostic may be AC coupled for use in systems with a low DC impedance between the center conductor and ground. The effect of DC bias on the breakdown threshold was studied: in coaxial geometry, the change in threshold was <1 dB for positive biases satisfying VD C/VR F 0 <0.8 , where VRF0 is the RF voltage amplitude at the unperturbed breakdown threshold. In parallel plate geometry, setting VD C/VR F 0 <0.2 was necessary to avoid altering the threshold by more than 1 dB. In most cases, the center conductor diagnostic functions effectively with no bias at all—this is the preferred implementation, but biases in the range VD C=0 -10 V may be applied if necessary. The polarity of the detected current signal may be positive or negative depending on whether there is net electron collection or emission globally.

Random-Forest Classification of High-Resolution Remote Sensing Images and Ndsm Over Urban Areas

NASA Astrophysics Data System (ADS)

Sun, X. F.; Lin, X. G.

2017-09-01

As an intermediate step between raw remote sensing data and digital urban maps, remote sensing data classification has been a challenging and long-standing research problem in the community of remote sensing. In this work, an effective classification method is proposed for classifying high-resolution remote sensing data over urban areas. Starting from high resolution multi-spectral images and 3D geometry data, our method proceeds in three main stages: feature extraction, classification, and classified result refinement. First, we extract color, vegetation index and texture features from the multi-spectral image and compute the height, elevation texture and differential morphological profile (DMP) features from the 3D geometry data. Then in the classification stage, multiple random forest (RF) classifiers are trained separately, then combined to form a RF ensemble to estimate each sample's category probabilities. Finally the probabilities along with the feature importance indicator outputted by RF ensemble are used to construct a fully connected conditional random field (FCCRF) graph model, by which the classification results are refined through mean-field based statistical inference. Experiments on the ISPRS Semantic Labeling Contest dataset show that our proposed 3-stage method achieves 86.9% overall accuracy on the test data.

RF study and 3-D simulations of a side-coupling thermionic RF-gun

NASA Astrophysics Data System (ADS)

Rimjaem, S.; Kusoljariyakul, K.; Thongbai, C.

2014-02-01

A thermionic RF-gun for generating ultra-short electron bunches was optimized, developed and used as a source at a linac-based THz radiation research laboratory of the Plasma and Beam Physics Research Facility, Chiang Mai University, Thailand. The RF-gun is a π/2-mode standing wave structure, which consists of two S-band accelerating cells and a side-coupling cavity. The 2856 MHz RF wave is supplied from an S-band klystron to the gun through the waveguide input-port at the cylindrical wall of the second cell. A fraction of the RF power is coupled from the second cell to the first one via a side-coupling cavity. Both the waveguide input-port and the side-coupling cavity lead to an asymmetric geometry of the gun. RF properties and electromagnetic field distributions inside the RF-gun were studied and numerically simulated by using computer codes SUPERFISH 7.19 and CST Microwave Studio 2012©. RF characterizations and tunings of the RF-gun were performed to ensure the reliability of the gun operation. The results from 3D simulations and measurements are compared and discussed in this paper. The influence of asymmetric field distributions inside the RF-gun on the electron beam properties was investigated via 3D beam dynamics simulations. A change in the coupling-plane of the side-coupling cavity is suggested to improve the gun performance.

Directed Energy: Medical Effects of Radio Frequency Exposure (Microwave & Millimeter Wave) - A Literature Review

DTIC Science & Technology

2013-01-01

Conwy G. Infection prevention and treatment in patients with major burn injuries . Nurs Stand 2010; 25(7):51-2, 54, 56-8. 39. Butler KL, Goverman J...14. ABSTRACT This literature review provides a relatively compact summary of research efforts on diagnosing, managing, and treating injuries caused...difference between RF- induced injuries and ordinary burns is the location of the damage. A unique characteristic of RF energy is its ability to penetrate

An algorithm for the design and tuning of RF accelerating structures with variable cell lengths

NASA Astrophysics Data System (ADS)

Lal, Shankar; Pant, K. K.

2018-05-01

An algorithm is proposed for the design of a π mode standing wave buncher structure with variable cell lengths. It employs a two-parameter, multi-step approach for the design of the structure with desired resonant frequency and field flatness. The algorithm, along with analytical scaling laws for the design of the RF power coupling slot, makes it possible to accurately design the structure employing a freely available electromagnetic code like SUPERFISH. To compensate for machining errors, a tuning method has been devised to achieve desired RF parameters for the structure, which has been qualified by the successful tuning of a 7-cell buncher to π mode frequency of 2856 MHz with field flatness <3% and RF coupling coefficient close to unity. The proposed design algorithm and tuning method have demonstrated the feasibility of developing an S-band accelerating structure for desired RF parameters with a relatively relaxed machining tolerance of ∼ 25 μm. This paper discusses the algorithm for the design and tuning of an RF accelerating structure with variable cell lengths.

Design of a New Water Load for S-band 750 kW Continuous Wave High Power Klystron Used in EAST Tokamak

NASA Astrophysics Data System (ADS)

Liu, Liang; Liu, Fukun; Shan, Jiafang; Kuang, Guangli

2007-04-01

In order to test the klystrons operated at a frequency of 3.7 GHz in a continuous wave (CW) mode, a type of water load to absorb its power up to 750 kW is presented. The distilled water sealed with an RF ceramic window is used as the absorbent. At a frequency range of 70 MHz, the VSWR (Voltage Standing Wave Ratio) is below 1.2, and the rise in temperature of water is about 30 oC at the highest power level.

Toroids as NMR detectors in metal pressure probes and in flow systems

DOEpatents

Rathke, Jerome W.

1991-01-01

A nuclear magnetic resonance probe to measure the properties of a sample under high pressure conditions. The apparatus employs a free standing, elongated toroidal coil as the RF transmitter and receiver.

Design study of an S-band RF cavity of a dual-energy electron LINAC for the CIS

NASA Astrophysics Data System (ADS)

Lee, Byeong-No; Park, Hyungdal; Song, Ki-baek; Li, Yonggui; Lee, Byung Cheol; Cha, Sung-su; Lee, Jong-Chul; Shin, Seung-Wook; Chai, Jong-seo

2014-01-01

The design of a resonance frequency (RF) cavity for the dual-energy S-band electron linear accelerator (LINAC) has been carried out for the cargo inspection system (CIS). This Standing-wave-type RF cavity is operated at a frequency under the 2856-MHz resonance frequency and generates electron beams of 9 MeV (high mode) and 6 MeV (low mode). The electrons are accelerated from the initial energy of the electron gun to the target energy (9 or 6 MeV) inside the RF cavity by using the RF power transmitted from a 5.5-MW-class klystron. Then, electron beams with a 1-kW average power (both high mode and low mode) bombard an X-ray target a 2-mm spot size. The proposed accelerating gradient was 13 MV/m, and the designed Q value was about 7100. On going research on 15-MeV non-destructive inspections for military or other applications is presented.

Modeling the effects of biological tissue on RF propagation from a wrist-worn device.

PubMed

Wilson, Jared D; Blanco, Justin A; Mazar, Scott; Bly, Mark

2014-01-01

Many wireless devices in common use today are worn either on or in close proximity to the body. Among them are a growing number of wrist-mounted devices designed for applications such as activity or vital-signs monitoring, typically using Bluetooth technology to communicate with external devices. Here, we use a tissue-mimicking phantom material in conjunction with anechoic chamber and network analyzer testing to investigate how antenna propagation patterns in one such device are influenced by the electrical properties of the human wrist. A microstrip antenna module is mounted onto phantom material of various geometries, and the resulting voltage standing wave ratio (VSWR), input impedance, and azimuth radiation pattern are recorded in both free space and real-world environments. The results of this study demonstrate how the high permittivity values of human tissue (ε(r) ≈ 16) affect the design parameters of microstrip antennas. A simulation environment using Sonnet EM software was used to further analyze the high dielectric effects of biological tissue on RF propagation.

Outcome of stand-alone thoracoscopic epicardial left atrial posterior box isolation with bipolar radiofrequency energy for longstanding persistent atrial fibrillation.

PubMed

Compier, M G; Braun, J; Tjon, A; Zeppenfeld, K; Klautz, R J M; Schalij, M J; Trines, S A

2016-02-01

Catheter ablation of longstanding (> 1 year) persistent atrial fibrillation (AF) is associated with poor outcome. This might be due to remodelling and fibrosis formation, mainly located in the posterior left atrial (LA) wall. Therefore, we adopted a thoracoscopic epicardial box isolation of the posterior left atrium using bipolar RF energy with intraoperative testing of conduction block. Bilateral thoracoscopic box isolation was performed with a bipolar RF clamp. Entrance block was defined as absence of a conducted electrogram within the box, while exit block was confirmed by pacing at 10.0 V/2 ms. Ablation outcome was evaluated after 3, 6, 12 and 24 months with 12-lead ECGs and 24-hour Holter recordings. Twenty-five consecutive patients were included (58 ± 7 years, persistent AF duration 1.8 ± 0.9 years). Entrance block was achieved in all patients and exit block confirmed if sinus rhythm was achieved. After 17 ± 7 months, 76 % of the patients (n = 19) were free of AF recurrence. One patient died within 1 month and was considered an ablation failure. Four patients with AF recurrences regained sinus rhythm with additional catheter ablation or antiarrhythmic drugs. Treatment of longstanding persistent AF with thoracoscopic epicardial LA posterior box isolation using bipolar RF energy with intraoperative testing of conduction block is feasible and highly effective.

High Power RF Testing of A 3-Cell Superconducting Traveling Wave Accelerating Structure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kanareykin, Alex; Kostin, Romna; Avrakhov, Pavel

Euclid Techlabs has completed the Phase II SBIR project, entitled “High Power RF Testing of a 3-Cell Superconducting Traveling Wave Accelerating Structure” under Grant #DE-SC0006300. In this final technical report, we summarize the major achievements of Phase I of the project and review the details of Phase II of the project. The accelerating gradient in a superconducting structure is limited mainly by quenching, i.e., by the maximum surface RF magnetic field. Various techniques have been developed to increase the gradient. A traveling wave accelerating SC structure with a feedback waveguide was suggested to allow an increased transit time factor andmore » ultimately, a maximum gradient that is 22%-24% higher than in the best of the time standing wave SRF cavity solution. The proposed structure has an additional benefit in that it can be fabricated much longer than the standing wave ones that are limited by the field flatness factor. Taken together, all of these factors will result in a significant overall length and, correspondingly cost reduction of the SRF based linear collider ILC or SRF technology based FELs. In Phase I of this project, a 3-cell L-band SC traveling wave cavity was designed. Cavity shape, surface field ratios, inter-cell coupling coefficients, accelerating field flatness have been reviewed with the analysis of tuning issues. Moreover, the technological aspects of SC traveling wave accelerating structure fabrication have been studied. As the next step in the project, the Phase II experimental program included engineering design, manufacturing, surface processing and high gradient testing. Euclid Techlabs, LLC contracted AES, Inc. to manufacture two niobium cavities. Euclid Techlabs cold tested traveling wave regime in the cavity, and the results showed very good agreement with mathematical model specially developed for superconducting traveling wave cavity performance analysis. Traveling wave regime was adjusted by amplitude and phase variation of input signals due to application of developed power feeding scheme. Traveling wave excitation, adjustment and detection were successfully tested. Auxiliary equipment required for high power test such as the tuner, power and measure couplers, holding plates for VTS at Fermilab were developed and successfully tested. Both TW SRF cavities were fabricated by AES, Inc. without stiffening ribs before this company closed their production facility. Currently Roark EB welding company is finishing now welding process of the cavity for the high power testing at Fermilab VTS. Successful demonstration of high gradients in the 3-cell cavity along with studies of traveling wave excitation and tuning issues is leading to successful development of superconducting traveling wave technology for ILC applications and other future high energy SC accelerators.« less

Imaging performance of a dedicated radiation transparent RF coil on a 1.0 Tesla inline MRI-linac.

PubMed

Liney, Gary P; Dong, Bin; Weber, Ewald; Rai, Robba; Destruel, Aurelien; Garcia-Alvarez, Roberto; Manton, David; Jelen, Urszula; Zhang, Kevin; Barton, Michael; Keall, Paul J; Crozier, Stuart

2018-05-25

This work describes the first imaging studies on a 1.0 Tesla inline MRI-Linac using a dedicated transmit/receive RF body coil that has been designed to be completely radio transparent and provide optimum imaging performance over a large patient opening. Methods: A series of experiments was performed on the MRI-Linac to investigate the performance and imaging characteristics of a new dedicated volumetric RF coil: (1) numerical electromagnetic simulations were used to measure transmit efficiency in two patient positions; (2) image quality metrics of signal-to-noise ratio (SNR), ghosting and uniformity were assessed in a large diameter phantom with no radiation beam; (3) radiation induced effects were investigated in both the raw data (k-space) and image sequences acquired with simultaneous irradiation; (4) radiation dose was measured with and without image acquisition; (5) RF heating was studied using an MR-compatible fluoroptic thermometer and; (6) the in vivo image quality and versatility of the coil was demonstrated in normal healthy subjects for both supine and standing positions. Results: Daily phantom measurements demonstrated excellent imaging performance with stable SNR over a period of 3 months (42.6 ± 0.9). Simultaneous irradiation produced no statistical change in image quality (p>0.74) and no interference in raw data for a 20  20 cm radiation field. The coil was found to be efficient over large volumes and negligible RF heating was observed. Volunteer scans acquired in both supine and standing positions provided artefact free images with good anatomical visualisation. Conclusions: The first completely radio transparent RF coil for use on a 1.0 Tesla MRI-Linac has been described. There is no impact on either the imaging or dosimetry performance with a simultaneous radiation beam. The open design enables imaging and radiotherapy guidance in a variety of positons. . © 2018 Institute of Physics and Engineering in Medicine.

X-Band RF Gun Development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vlieks, Arnold; Dolgashev, Valery; Tantawi, Sami

In support of the MEGa-ray program at LLNL and the High Gradient research program at SLAC, a new X-band multi-cell RF gun is being developed. This gun, similar to earlier guns developed at SLAC for Compton X-ray source program, will be a standing wave structure made of 5.5 cells operating in the pi mode with copper cathode. This gun was designed following criteria used to build SLAC X-band high gradient accelerating structures. It is anticipated that this gun will operate with surface electric fields on the cathode of 200 MeV/m with low breakdown rate. RF will be coupled into themore » structure through a final cell with symmetric duel feeds and with a shape optimized to minimize quadrupole field components. In addition, geometry changes to the original gun, operated with Compton X-ray source, will include a wider RF mode separation, reduced surface electric and magnetic fields.« less

Design of 6 MeV X-band electron linac for dual-head gantry radiotherapy system

NASA Astrophysics Data System (ADS)

Shin, Seung-wook; Lee, Seung-Hyun; Lee, Jong-Chul; Kim, Huisu; Ha, Donghyup; Ghergherehchi, Mitra; Chai, Jongseo; Lee, Byung-no; Chae, Moonsik

2017-12-01

A compact 6 MeV electron linac is being developed at Sungkyunkwan University, in collaboration with the Korea atomic energy research institute (KAERI). The linac will be used as an X-ray source for a dual-head gantry radiotherapy system. X-band technology has been employed to satisfy the size requirement of the dual-head gantry radiotherapy machine. Among the several options available, we selected a pi/2-mode, standing-wave, side-coupled cavity. This choice of radiofrequency (RF) cavity design is intended to enhance the shunt impedance of each cavity in the linac. An optimum structure of the RF cavity with a high-performance design was determined by applying a genetic algorithm during the optimization procedure. This paper describes the detailed design process for a single normal RF cavity and the entire structure, including the RF power coupler and coupling cavity, as well as the beam dynamics results.

Carbon Cryogel and Carbon Paper-Based Silicon Composite Anode Materials for Lithium-Ion Batteries

NASA Technical Reports Server (NTRS)

Woodworth, James; Baldwin, Richard; Bennett, William

2010-01-01

A variety of materials are under investigation for use as anode materials in lithium-ion batteries, of which, the most promising are those containing silicon. 6 One such material is a composite formed via the dispersion of silicon in a resorcinol-formaldehyde (RF) gel followed by pyrolysis. Two silicon-carbon composite materials, carbon microspheres and nanofoams produced from nano-phase silicon impregnated RF gel precursors have been synthesized and investigated. Carbon microspheres are produced by forming the silicon-containing RF gel into microspheres whereas carbon nano-foams are produced by impregnating carbon fiber paper with the silicon containing RF gel to create a free standing electrode. 1-5 Both materials have demonstrated their ability to function as anodes and utilize the silicon present in the material. Stable reversible capacities above 400 mAh/g for the bulk material and above 1000 mAh/g of Si have been observed.

Silicon Composite Anode Materials for Lithium Ion Batteries Based on Carbon Cryogels and Carbon Paper

NASA Technical Reports Server (NTRS)

Woodworth, James; Baldwin, Richard; Bennett, William

2010-01-01

A variety of materials are under investigation for use as anode materials in lithium-ion batteries, of which, the most promising are those containing silicon. One such material is a composite formed via the dispersion of silicon in a resorcinol-formaldehyde (RF) gel followed by pyrolysis. Two silicon-carbon composite materials, carbon microspheres and nanofoams produced from nano-phase silicon impregnated RF gel precursors have been synthesized and investigated. Carbon microspheres are produced by forming the silicon-containing RF gel into microspheres whereas carbon nanofoams are produced by impregnating carbon fiber paper with the silicon containing RF gel to create a free standing electrode. Both materials have demonstrated their ability to function as anodes and utilize the silicon present in the material. Stable reversible capacities above 400 mAh/g for the bulk material and above 1000 mAh/g of Si have been observed.

Carbon Cryogel Silicon Composite Anode Materials for Lithium Ion Batteries

NASA Technical Reports Server (NTRS)

Woodworth James; Baldwin, Richard; Bennett, William

2010-01-01

A variety of materials are under investigation for use as anode materials in lithium-ion batteries, of which, the most promising are those containing silicon. 10 One such material is a composite formed via the dispersion of silicon in a resorcinol-formaldehyde (RF) gel followed by pyrolysis. Two silicon-carbon composite materials, carbon microspheres and nanofoams produced from nano-phase silicon impregnated RF gel precursors have been synthesized and investigated. Carbon microspheres are produced by forming the silicon-containing RF gel into microspheres whereas carbon nano-foams are produced by impregnating carbon fiber paper with the silicon containing RF gel to create a free standing electrode. 1-4,9 Both materials have demonstrated their ability to function as anodes and utilize the silicon present in the material. Stable reversible capacities above 400 mAh/g for the bulk material and above 1000 mAh/g of Si have been observed.

A Compact High-Brightness Heavy-Ion Injector

DOE Office of Scientific and Technical Information (OSTI.GOV)

Westenskow, G A; Grote, D P; Halaxa, E

2005-05-11

To provide a compact high-brightness heavy-ion beam source for Heavy Ion Fusion (HIF) accelerators, we have been experimenting with merging multi-beamlets in an injector which uses an RF plasma source. In an 80-kV 20-microsecond experiment, the RF plasma source has produced up to 5 mA of Ar{sup +} in a single beamlet. An extraction current density of 100 mA/cm{sup 2} was achieved, and the thermal temperature of the ions was below 1 eV. We have tested at full voltage gradient the first 4 gaps of an injector design. Einzel lens were used to focus the beamlets while reducing the beamletmore » to beamlet space charge interaction. We were able to reach greater than 100 kV/cm in the first four gaps. We also performed experiments on a converging 119 multi-beamlet source. Although the source has the same optics as a full 1.6 MV injector system, these test were carried out at 400 kV due to the test stand HV limit. We have measured the beam's emittance after the beamlets are merged and passed through an electrostatic quadrupole (ESQ). Our goal is to confirm the emittance growth and to demonstrate the technical feasibility of building a driver-scale HIF injector.« less

Electrochemical properties of free-standing Sn/SnO2/multi-walled carbon nano tube anode papers for Li-ion batteries

NASA Astrophysics Data System (ADS)

Alaf, M.; Gultekin, D.; Akbulut, H.

2013-06-01

Free-standing multiwalled carbon nano tube papers (buckypapers) were prepared by vacuum filtration from functionalized multi walled carbon nano tubes (MWCNTs) with controlling porosity. Double phase matrix Sn/SnO2/MWCNT nanocomposites were obtained in two steps, including thermal evaporation of metallic tin (Sn) on the MWCNT papers and RF plasma oxidation. The ratio between metallic tin (Sn) and tin oxide (SnO2) was controlled with plasma oxidation time. It was determined that the evaporated pure tin nano crystals were mechanically penetrated into pores of buckypapers to form functionally gradient nanocomposites. Sn/SnO2 coated on MWCNT buckypapers were used as working electrodes in assembled as coin-type (CR2016) test cells. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to determine the structure and morphology of the obtained nanocomposites. In addition, the discharge/charge test, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were carried out to characterize the electrochemical properties of these composites as anode materials for Li-ion batteries.

[Effects of land use changes on soil water conservation in Hainan Island, China].

PubMed

Wen, Zhi; Zhao, He; Liu, Lei; OuYang, Zhi Yun; Zheng, Hua; Mi, Hong Xu; Li, Yan Min

2017-12-01

In tropical areas, a large number of natural forests have been transformed into other plantations, which affected the water conservation function of terrestrial ecosystems. In order to clari-fy the effects of land use changes on soil water conservation function, we selected four typical land use types in the central mountainous region of Hainan Island, i.e., natural forests with stand age greater than 100 years (VF), secondary forests with stand age of 10 years (SF), areca plantations with stand age of 12 years (AF) and rubber plantations with stand age of 35 years (RF). The effects of land use change on soil water holding capacity and water conservation (presented by soil water index, SWI) were assessed. The results showed that, compared with VF, the soil water holding capacity index of other land types decreased in the top soil layer (0-10 cm). AF had the lowest soil water holding capacity in all soil layers. Soil water content and maximum water holding capacity were significantly related to canopy density, soil organic matter and soil bulk density, which indicated that canopy density, soil organic matter and compactness were important factors influencing soil water holding capacity. Compared to VF, soil water conservation of SF, AF and RF were reduced by 27.7%, 54.3% and 11.5%, respectively. The change of soil water conservation was inconsistent in different soil layers. Vegetation canopy density, soil organic matter and soil bulk density explained 83.3% of the variance of soil water conservation. It was suggested that land use conversion had significantly altered soil water holding capacity and water conservation function. RF could keep the soil water better than AF in the research area. Increasing soil organic matter and reducing soil compaction would be helpful to improve soil water holding capacity and water conservation function in land management.

Design and Vertical Tests of SPS-series Double-Quarter Wave (DQW) Cavity Prototypes for the HL-LHC Crab Cavity System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Verdú-Andrés, S.; et al.

Crab crossing is essential for high-luminosity colliders. The High Luminosity Large Hadron Collider (HL-LHC) will equip one of its Interaction Points (IP1) with Double-Quarter Wave (DQW) crab cavities. A DQW cavity is a new generation of deflecting RF cavities that stands out for its compactness and broad frequency separation between fundamental and first high-order modes. The deflecting kick is provided by its fundamental mode. Each HL-LHC DQW cavity shall provide a nominal deflecting voltage of 3.4 MV, although up to 5.0 MV may be required. A Proof-of-Principle (PoP) DQW cavity was limited by quench at 4.6 MV. This paper describesmore » a new, highly optimized cavity, designated DQW SPS-series, which satisfies dimensional, cryogenic, manufacturing and impedance requirements for beam tests at SPS and operation in LHC. Two prototypes of this DQW SPS-series were fabricated by US industry and cold tested after following conventional SRF surface treatment. Both units outperformed the PoP cavity, reaching a deflecting voltage of 5.3-5.9 MV. This voltage - the highest reached by a DQW cavity - is well beyond the nominal voltage of 3.4 MV and may even operate at the ultimate voltage of 5.0MVwith sufficient margin. This paper covers fabrication, surface preparation and cryogenic RF test results and implications.« less

An in vitro investigation into retention strength and fatigue resistance of various designs of tooth/implant supported overdentures.

PubMed

Fatalla, Abdalbseet A; Song, Ke; Du, Tianfeng; Cao, Yingguang

2012-02-01

Previously, the choice of prosthetic implant-retained overdentures has depended on data from previous studies about the retention-fatigue strength of the attachment system selected. Little or no data have been available on the correlation between the attachment system selected and the overdenture support configuration. The purpose of the present study was to evaluate the retention force and fatigue resistance of three attachment systems and four support designs of overdenture prosthesis. Four lower edentulous acrylic models were prepared and eight combinations of attachments groups were investigated in the study. These included: O-Rings with mini-dental implants (MDIs), Dalbo elliptic with Dalbo Rotex and fabricated flexible acrylic attachments with both MDI and Dalbo Rotex. The study was divided into four test groups: groups A and B, controls, and groups C and D, experimental groups. Control group A contained three overdenture supports: two free standing MDIs in the canine region and at the midline, and one simulated tooth root with Dalbo Rotex screwed in. Control group B contained four overdenture support foundations: two free standing MDIs in the right canine region and the first premolar region, and two simulated tooth roots with Dalbo Rotex screwed in at the same MDI position, but on the left side of the model. Experimental group C contained three overdenture support foundations: two free standing MDIs in the canine region and at the midline, and one simulated tooth root with MDI screwed in. Experimental group D contained four overdenture support foundations: two free standing MDIs in the right canine region and the first premolar region, and two simulated tooth roots with MDIs screwed in at the same MDI position, but on the left side of the model. Each group was further divided into two subgroups according to attachment type used. Five samples were prepared for each group. Retention force (N) values were recorded initially (0 cycles) and after 360, 720, 1440 and 2880 insertion and removal cycles. During the tensile test a cross-head speed of 10 mm/min was applied. Values of absolute force (AF) and relative force (RF) were statistically analyzed by two-way ANOVA and multiple comparison Tukey's tests between groups and cycles periods. The results of fatigue tests showed a 50% reduction in retention force in the subgroups with flexible attachments. A triangular design of overdenture support foundations with O-Ring attachments revealed the lowest value of AF and a relatively high reduction in RF. The four overdenture support designs with flexible acrylic attachments improved the retention force and reduced the fatigue retention. Furthermore, the results of the investigation demonstrate that flexible acrylic attachments for both teeth and implant-supported overdentures offer a wide range of retention forces.

Beam Dynamics Simulation of Photocathode RF Electron Gun at the PBP-CMU Linac Laboratory

NASA Astrophysics Data System (ADS)

Buakor, K.; Rimjaem, S.

2017-09-01

Photocathode radio-frequency (RF) electron guns are widely used at many particle accelerator laboratories due to high quality of produced electron beams. By using a short-pulse laser to induce the photoemission process, the electrons are emitted with low energy spread. Moreover, the photocathode RF guns are not suffered from the electron back bombardment effect, which can cause the limited electron current and accelerated energy. In this research, we aim to develop the photocathode RF gun for the linac-based THz radiation source. Its design is based on the existing gun at the PBP-CMU Linac Laboratory. The gun consists of a one and a half cell S-band standing-wave RF cavities with a maximum electric field of about 60 MV/m at the centre of the full cell. We study the beam dynamics of electrons traveling through the electromagnetic field inside the RF gun by using the particle tracking program ASTRA. The laser properties i.e. transverse size and injecting phase are optimized to obtain low transverse emittance. In addition, the solenoid magnet is applied for beam focusing and emittance compensation. The proper solenoid magnetic field is then investigated to find the optimum value for proper emittance conservation condition.

Muscle quality characteristics of muscles in the thigh, upper arm and lower back in elderly men and women.

PubMed

Yoshiko, Akito; Kaji, Takashi; Sugiyama, Hiroki; Koike, Teruhiko; Oshida, Yoshiharu; Akima, Hiroshi

2018-04-23

The ratio of fat within skeletal muscle is an important parameter that is indicative of muscle quality, and can be assessed using ultrasonography to measure echo intensity (EI). Muscle EI indicates muscle strength and risk of physical dysfunction; however, this observation was determined following examinations of only selected muscle. The purpose of this study was to investigate the EI characteristics of muscles in several regions in elderly men and women, using physical function tests and serum cholesterol levels. Twenty-two men and women (age 78 ± 8 years) participated in this study. The EIs were calculated from rectus femoris (RF), biceps femoris (BF) triceps brachii (TB) and multifidus (MF) using B-mode transverse ultrasound images. Seven functional tests (isometric knee-extension peak torque, functional reach, sit-to-stand, 5-m normal/maximal speed walking, handgrip strength and timed up-and-go) and blood lipid components including adipocytokines were measured in all participants. A statistically significant correlation between EI of the RF, TB and BF was observed (r = 0.46-0.50, P < 0.05), but not between EI of the MF and that of other muscles. EI of muscles of the limbs, which was averaged EI for RF, TB and BF, was negatively correlated with leptin levels (adjusted R 2  = 0.27, P < 0.01), and EI of the MF was correlated with muscle mass and performance in the timed up-and-go test (adjusted R 2  = 0.61, P < 0.01). These results suggest that EI might be influenced by specific parameters depending on the location of the muscle.

Spontaneous Magnetic Alignment by Yearling Snapping Turtles: Rapid Association of Radio Frequency Dependent Pattern of Magnetic Input with Novel Surroundings

PubMed Central

Landler, Lukas; Painter, Michael S.; Youmans, Paul W.; Hopkins, William A.; Phillips, John B.

2015-01-01

We investigated spontaneous magnetic alignment (SMA) by juvenile snapping turtles using exposure to low-level radio frequency (RF) fields at the Larmor frequency to help characterize the underlying sensory mechanism. Turtles, first introduced to the testing environment without the presence of RF aligned consistently towards magnetic north when subsequent magnetic testing conditions were also free of RF (‘RF off → RF off’), but were disoriented when subsequently exposed to RF (‘RF off → RF on’). In contrast, animals initially introduced to the testing environment with RF present were disoriented when tested without RF (‘RF on → RF off’), but aligned towards magnetic south when tested with RF (‘RF on → RF on’). Sensitivity of the SMA response of yearling turtles to RF is consistent with the involvement of a radical pair mechanism. Furthermore, the effect of RF appears to result from a change in the pattern of magnetic input, rather than elimination of magnetic input altogether, as proposed to explain similar effects in other systems/organisms. The findings show that turtles first exposed to a novel environment form a lasting association between the pattern of magnetic input and their surroundings. However, under natural conditions turtles would never experience a change in the pattern of magnetic input. Therefore, if turtles form a similar association of magnetic cues with the surroundings each time they encounter unfamiliar habitat, as seems likely, the same pattern of magnetic input would be associated with multiple sites/localities. This would be expected from a sensory input that functions as a global reference frame, helping to place multiple locales (i.e., multiple local landmark arrays) into register to form a global map of familiar space. PMID:25978736

Spontaneous magnetic alignment by yearling snapping turtles: rapid association of radio frequency dependent pattern of magnetic input with novel surroundings.

PubMed

Landler, Lukas; Painter, Michael S; Youmans, Paul W; Hopkins, William A; Phillips, John B

2015-01-01

We investigated spontaneous magnetic alignment (SMA) by juvenile snapping turtles using exposure to low-level radio frequency (RF) fields at the Larmor frequency to help characterize the underlying sensory mechanism. Turtles, first introduced to the testing environment without the presence of RF aligned consistently towards magnetic north when subsequent magnetic testing conditions were also free of RF ('RF off → RF off'), but were disoriented when subsequently exposed to RF ('RF off → RF on'). In contrast, animals initially introduced to the testing environment with RF present were disoriented when tested without RF ('RF on → RF off'), but aligned towards magnetic south when tested with RF ('RF on → RF on'). Sensitivity of the SMA response of yearling turtles to RF is consistent with the involvement of a radical pair mechanism. Furthermore, the effect of RF appears to result from a change in the pattern of magnetic input, rather than elimination of magnetic input altogether, as proposed to explain similar effects in other systems/organisms. The findings show that turtles first exposed to a novel environment form a lasting association between the pattern of magnetic input and their surroundings. However, under natural conditions turtles would never experience a change in the pattern of magnetic input. Therefore, if turtles form a similar association of magnetic cues with the surroundings each time they encounter unfamiliar habitat, as seems likely, the same pattern of magnetic input would be associated with multiple sites/localities. This would be expected from a sensory input that functions as a global reference frame, helping to place multiple locales (i.e., multiple local landmark arrays) into register to form a global map of familiar space.

Integrated Advanced Microwave Sounding Unit-A (AMSU-A). Performance Verification Report, METSAT (S/N:107) AMSU-A1 Receiver Assemblies: P/N 1356429-1, S/N:F04, P/N 1356409-1,S/N F04

NASA Technical Reports Server (NTRS)

Pines, D.

1999-01-01

This is the Performance Verification Report, METSAT (S/N: 107) AMSU-A1 Receiver Assemblies, P/N 1356429-1, SIN: F04, P/N 1356409- 1, S/N: F04, for the Integrated Advanced Microwave Sounding Unit-A (AMSU-A). The AMSU-A receiver subsystem comprises two separated receiver assemblies; AMSU-A1 and AMSU-A2 (P/N 1356441-1). The AMSU-A1 receiver contains 13 channels and the AMSU-A2 receiver 2 channels. The AMSU-A receiver assembly is further divided into two parts; AMSU-A I - I (P/N 13 5 6429- 1) and AMSU-A 1 -2 (P/N 1356409-1), which contain 9 and 4 channels, respectively. The AMSU-A receiver subsystem is located in between the antenna and signal processing subsystems of the AMSU-A instrument and comprises the RF and IF components from isolators to attenuators. It receives the RF signals from the antenna subsystem, down-converts the RF signals to IF signals, amplifies and defines the IF signals to proper power level and frequency bandwidth as specified for each channel, and inputs the IF signals to the signal processing subsystem. The test reports for the METSAT AMSU-A receiver subsystem are prepared separately for Al and A2 receivers so that each receiver stands alone during integration of instruments into the spacecraft. This test report presents the test data of the N4ETSAT AMSU-A1 Flight Model No. 4 (FM-4) receiver subsystem. The tests are performed per the Acceptance Test Procedure (ATP) for the AMSU-A Receiver Subsystem, AE-26002/6A. The functional performance tests are conducted either at the component or subsystem level. While the component-level tests are performed over the entire operating temperature range predicted by thermal analysis, most subsystem-level tests are conducted at ambient temperature only. Key performances (bandpass characteristics and noise figure) of the receiver subsystem are verified over the operating temperature.

Commissioning of two RF operation modes for RF negative ion source experimental setup at HUST

NASA Astrophysics Data System (ADS)

Li, D.; Chen, D.; Liu, K.; Zhao, P.; Zuo, C.; Wang, X.; Wang, H.; Zhang, L.

2017-08-01

An RF-driven negative ion source experimental setup, without a cesium oven and an extraction system, has been built at Huazhong University of Science and Technology (HUST). The working gas is hydrogen, and the typical operational gas pressure is 0.3 Pa. The RF generator is capable of delivering up to 20 kW at 0.9 - 1.1 MHz, and has two operation modes, the fixed-frequency mode and auto-tuning mode. In the fixed-frequency mode, it outputs a steady RF forward power (Pf) at a fixed frequency. In the auto-tuning mode, it adjusts the operating frequency to seek and track the minimum standing wave ratio (SWR) during plasma discharge. To achieve fast frequency tuning, the RF signal source adopts a direct digital synthesizer (DDS). To withstand high SWR during the discharge, a tetrode amplifier is chosen as the final stage amplifier. The trend of maximum power reflection coefficient |ρ|2 at plasma ignition is presented at the fixed frequency of 1.02 MHz with the Pf increasing from 5 kW to 20 kW, which shows the maximum |ρ|2 tends to be "steady" under high RF power. The experiments in auto-tuning mode fail due to over-current protection of screen grid. The possible reason is the relatively large equivalent anode impedance caused by the frequency tuning. The corresponding analysis and possible solution are presented.

The 140 GHZ, 1 MW Gyrotron - Status and Recent Results

NASA Astrophysics Data System (ADS)

Gantenbein, G.; Dammertz, G.; Illy, S.; Kern, S.; Leonhardt, W.; Piosczyk, B.; Schmid, M.; Thumm, M.; Braune, H.; Erckmann, V.; Laqua, H. P.; Michel, G.; Kasparek, W.; Lechte, C.; Legrand, F.; Lievin, C.; Prinz, O.

2009-04-01

A 10 MW ECRH system is currently under construction for the stellarator W7-X which will be built up and operated by IPP in Greifswald, Germany. The present status of the complete system is reported in [1]. The RF power will be provided by 10 gyrotrons. A European collaboration has been established to develop and build the 10 gyrotrons each with an output power of 1 MW for continuous wave (CW) operation [2]. Nine gyrotrons are being manufactured by Thales Electron Devices (TED), Vélizy, France, one gyrotron was produced by CPI, Palo Alto, CA and passed the acceptance tests at IPP. The acceptance tests of the TED gyrotrons are performed at the test stand at FZK and on site at IPP. The first series tube yielded a total output power of 0.98 MW, with an efficiency of 31 % (without a single stage depressed collector) in short pulse operation and of 0.92 MW in pulses of 1800 s (efficiency of almost 45 % at a depression voltage of 29 kV) [3], The Gaussian mode output power was 0.91 MW. The RF power, measured in a calorimetric load at the end of a 25 m long quasi-optical transmission line with seven mirrors, was 0.87 MW. In this contribution typical results of the next series gyrotrons will be reported.

Developing field emission electron sources based on ultrananocrystalline diamond for accelerators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baryshev, Sergey V.; Jing, Chunguang; Qiu, Jiaqi

Radiofrequency (RF) electron guns work by establishing an RF electromagnetic field inside a cavity having conducting walls. Electrons from a cathode are generated in the injector and immediately become accelerated by the RF electric field, and exit the gun as a series of electron bunches. Finding simple solutions for electron injection is a long standing problem. While energies of 30-50 MeV are achievable in linear accelerators (linacs), finding an electron source able to survive under MW electric loads and provide an average current of 1-10 mA is important. Meeting these requirements would open various linac applications for industry. The naturalmore » way to simplify and integrate RF injector architectures with the electron source would be to place the source directly into the RF cavity with no need for additional heaters/lasers. Euclid TechLabs in collaboration with Argonne National Lab are prototyping a family of highly effective field emission electron sources based on a nitrogen-incorporated ultrananocrystalline diamond ((N)UNCD) platform. Determined metrics suggest that our emitters are emissive enough to meet requirements for magnetized cooling at electron-ion colliders, linac-based radioisotope production and X-ray sterilization, and others.« less

Evaluation of the MMPI-2-RF for Detecting Over-reported Symptoms in a Civil Forensic and Disability Setting.

PubMed

Nguyen, Constance T; Green, Debbie; Barr, William B

2015-01-01

This study investigated the classification accuracy of the Minnesota Multiphasic Personality Inventory-2-Restructured Form validity scales in a sample of disability claimants and civil forensic litigants. A criterion-groups design was used, classifying examinees as "Failed Slick Criteria" through low performance on at least two performance validity indices (stand-alone or embedded) and "Passed Slick Criteria." The stand-alone measures included the Test of Memory Malingering and the Dot Counting Test. The embedded indices were extracted from the Wechsler Adult Intelligence Scales Digit Span and Vocabulary subtests, the California Verbal Learning Test-II, and the Wisconsin Card Sorting Test. Among groups classified by primary complaints at the time of evaluation, those alleging neurological conditions were more frequently classified as Failed Slick Criteria than those alleging psychiatric or medical conditions. Among those with neurological or psychiatric complaints, the F-r, FBS-r, and RBS scales differentiated between those who Passed Slick Criteria from those who Failed Slick Criteria. The Fs scale was also significantly higher in the Failed Slick Criteria compared to Passed Slick Criteria examinees within the psychiatric complaints group. Results indicated that interpretation of scale scores should take into account the examinees' presenting illness. While this study has limitations, it highlights the possibility of different cutoffs depending on the presenting complaints and the need for further studies to cross-validate the results.

Contralateral regional recurrence after elective unilateral neck irradiation in oropharyngeal carcinoma: A literature-based critical review.

PubMed

Al-Mamgani, Abrahim; van Werkhoven, Erik; Navran, Arash; Karakullukcu, Baris; Hamming-Vrieze, Olga; Machiels, Melanie; van der Velden, Lilly-Ann; Vogel, Wouter V; Klop, W Martin

2017-09-01

The head and neck region has rich regional lymphatic network, with a theoretical risk on contralateral metastasis from oropharyngeal cancer (OPC). There is a long-standing convention to irradiate the great majority of these tumors electively to both sides of the neck to reduce the risk of contralateral regional failure (cRF), but this can induce significant toxicity. We aimed to identify patient groups where elective contralateral irradiation may safely be omitted. PubMed and EMBASE were searched for original full-text articles in English with a combination of search terms related to the end points: cRF in OPC primarily treated by radiotherapy only to the ipsilateral neck and identifying predictive factors for increased incidence of cRF. The data from the identified studies were pooled, the incidence of cRF was calculated and the correlation with different predictive factors was investigated. Eleven full-text articles met the inclusion criteria. In these studies, 1116 patients were treated to the ipsilateral neck alone. The mean incidence of cRF was 2.42% (range 0-5.9%, 95% CI 1.6-3.5%). The incidence of cRF correlated only with T-stage (p=0.008), and involvement of midline (p=0.001). However, the significant correlation with T-stage can be explained by the very low incidence of cRF among T1 (0.77%), and disappeared when the incidence of cRF was compared between T2, T3,and T4 (p=0.344). The incidence of cRF in patients with OPC is very low, with involvement of midline providing the most significant prognosticator. These results call for trials on unilateral elective irradiation in selected groups. Copyright © 2017 Elsevier Ltd. All rights reserved.

High-power microstrip RF switch

NASA Technical Reports Server (NTRS)

Choi, S. D.

1971-01-01

A microstrip-type single-pole double-throw (SPDT) switch whose RF and bias portions contain only a metallized alumina substrate and two PIN diodes has been developed. A technique developed to eliminate the dc blocking capacitors needed for biasing the diodes is described. These capacitors are extra components and could lower the reliability significantly. An SPDT switch fabricated on a 5.08 x 5.08 x 0.127-cm (2 x 2 x 0.050-in.) substrate has demonstrated an RF power-handling capability greater than 50 W at S-band. The insertion loss is less than 0.25 db and the input-to-off port isolation is greater than 36 db over a bandwidth larger than 30 MHz. The input voltage standing-wave ratio is lower than 1.07 over the same bandwidth. Theoretical development of the switch characteristics and experimental results, which are in good agreement with theory, are presented.

rf traveling-wave electron gun for photoinjectors

NASA Astrophysics Data System (ADS)

Schaer, Mattia; Citterio, Alessandro; Craievich, Paolo; Reiche, Sven; Stingelin, Lukas; Zennaro, Riccardo

2016-07-01

The design of a photoinjector, in particular that of the electron source, is of central importance for free electron laser (FEL) machines where a high beam brightness is required. In comparison to standard designs, an rf traveling-wave photocathode gun can provide a more rigid beam with a higher brightness and a shorter pulse. This is illustrated by applying a specific optimization procedure to the SwissFEL photoinjector, for which a brightness improvement up to a factor 3 could be achieved together with a double gun output energy compared to the reference setup foreseeing a state-of-the-art S-band rf standing-wave gun. The higher brightness is mainly given by a (at least) double peak current at the exit of the gun which brings benefits for both the beam dynamics in the linac and the efficiency of the FEL process. The gun design foresees an innovative coaxial rf coupling at both ends of the structure which allows a solenoid with integrated bucking coil to be placed around the cathode in order to provide the necessary focusing right after emission.

Development and performance test of a new high power RF window in S-band PLS-II LINAC

NASA Astrophysics Data System (ADS)

Hwang, Woon-Ha; Joo, Young-Do; Kim, Seung-Hwan; Choi, Jae-Young; Noh, Sung-Ju; Ryu, Ji-Wan; Cho, Young-Ki

2017-12-01

A prototype of RF window was developed in collaboration with the Pohang Accelerator Laboratory (PAL) and domestic companies. High power performance tests of the single RF window were conducted at PAL to verify the operational characteristics for its application in the Pohang Light Source-II (PLS-II) linear accelerator (Linac). The tests were performed in the in-situ facility consisting of a modulator, klystron, waveguide network, vacuum system, cooling system, and RF analyzing equipment. The test results with Stanford linear accelerator energy doubler (SLED) have shown no breakdown up to 75 MW peak power with 4.5 μs RF pulse width at a repetition rate of 10 Hz. The test results with the current operation level of PLS-II Linac confirm that the RF window well satisfies the criteria for PLS-II Linac operation.

Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF) scores generated from the MMPI-2 and MMPI-2-RF test booklets: internal structure comparability in a sample of criminal defendants.

PubMed

Tarescavage, Anthony M; Alosco, Michael L; Ben-Porath, Yossef S; Wood, Arcangela; Luna-Jones, Lynn

2015-04-01

We investigated the internal structure comparability of Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF) scores derived from the MMPI-2 and MMPI-2-RF booklets in a sample of 320 criminal defendants (229 males and 54 females). After exclusion of invalid protocols, the final sample consisted of 96 defendants who were administered the MMPI-2-RF booklet and 83 who completed the MMPI-2. No statistically significant differences in MMPI-2-RF invalidity rates were observed between the two forms. Individuals in the final sample who completed the MMPI-2-RF did not statistically differ on demographics or referral question from those who were administered the MMPI-2 booklet. Independent t tests showed no statistically significant differences between MMPI-2-RF scores generated with the MMPI-2 and MMPI-2-RF booklets on the test's substantive scales. Statistically significant small differences were observed on the revised Variable Response Inconsistency (VRIN-r) and True Response Inconsistency (TRIN-r) scales. Cronbach's alpha and standard errors of measurement were approximately equal between the booklets for all MMPI-2-RF scales. Finally, MMPI-2-RF intercorrelations produced from the two forms yielded mostly small and a few medium differences, indicating that discriminant validity and test structure are maintained. Overall, our findings reflect the internal structure comparability of MMPI-2-RF scale scores generated from MMPI-2 and MMPI-2-RF booklets. Implications of these results and limitations of these findings are discussed. © The Author(s) 2014.

Alternating phase focused linacs

DOEpatents

Swenson, Donald A.

1980-01-01

A heavy particle linear accelerator employing rf fields for transverse and ongitudinal focusing as well as acceleration. Drift tube length and gap positions in a standing wave drift tube loaded structure are arranged so that particles are subject to acceleration and succession of focusing and defocusing forces which contain the beam without additional magnetic or electric focusing fields.

Operation and development status of the J-PARC ion source

NASA Astrophysics Data System (ADS)

Yamazaki, S.; Ikegami, K.; Ohkoshi, K.; Ueno, A.; Koizumi, I.; Takagi, A.; Oguri, H.

2014-02-01

A cesium-free H- ion source driven with a LaB6 filament is being operated at the Japan Proton Accelerator Research Complex (J-PARC) without any serious trouble since the restoration from the March 2011 earthquake. The H- ion current from the ion source is routinely restricted approximately 19 mA for the lifetime of the filament. In order to increase the beam power at the linac beam operation (January to February 2013), the beam current from the ion source was increased to 22 mA. At this operation, the lifetime of the filament was estimated by the reduction in the filament current. According to the steep reduction in the filament current, the break of the filament was predicted. Although the filament has broken after approximately 10 h from the steep current reduction, the beam operation was restarted approximately 8 h later by the preparation for the exchange of new filament. At the study time for the 3 GeV rapid cycling synchrotron (April 2013), the ion source was operated at approximately 30 mA for 8 days. As a part of the beam current upgrade plan for the J-PARC, the front end test stand consisting of the ion source and the radio frequency quadrupole is under preparation. The RF-driven H- ion source developed for the J-PARC 2nd stage requirements will be tested at this test stand.

Generation of multiple analog pulses with different duty cycles within VME control system for ICRH Aditya system

NASA Astrophysics Data System (ADS)

Joshi, Ramesh; Singh, Manoj; Jadav, H. M.; Misra, Kishor; Kulkarni, S. V.; ICRH-RF Group

2010-02-01

Ion Cyclotron Resonance Heating (ICRH) is a promising heating method for a fusion device due to its localized power deposition profile, a direct ion heating at high density, and established technology for high RF power generation and transmission at low cost. Multiple analog pulse with different duty cycle in master of digital pulse for Data acquisition and Control system for steady state RF ICRH System(RF ICRH DAC) to be used for operating of RF Generator in Aditya to produce pre ionization and second analog pulse will produce heating. The control system software is based upon single digital pulse operation for RF source. It is planned to integrate multiple analog pulses with different duty cycle in master of digital pulse for Data acquisition and Control system for RF ICRH System(RF ICRH DAC) to be used for operating of RF Generator in Aditya tokamak. The task of RF ICRH DAC is to control and acquisition of all ICRH system operation with all control loop and acquisition for post analysis of data with java based tool. For pre ionization startup as well as heating experiments using multiple RF Power of different powers and duration. The experiment based upon the idea of using single RF generator to energize antenna inside the tokamak to radiate power twise, out of which first analog pulse will produce pre ionization and second analog pulse will produce heating. The whole system is based on standard client server technology using tcp/ip protocol. DAC Software is based on linux operating system for highly reliable, secure and stable system operation in failsafe manner. Client system is based on tcl/tk like toolkit for user interface with c/c++ like environment which is reliable programming languages widely used on stand alone system operation with server as vxWorks real time operating system like environment. The paper is focused on the Data acquisition and monitoring system software on Aditya RF ICRH System with analog pulses in slave mode with digital pulse in master mode for control acquisition and monitoring and interlocking.

Instrumentation and test methods of an automated radiated susceptibility system

NASA Astrophysics Data System (ADS)

Howard, M. W.; Deere, J.

1983-09-01

The instrumentation and test methods of an automated electromagnetic compatibility (EMC) system for performing radiated susceptibility tests from 14 kHz to 1000 MHz is described. Particular emphasis is given to the effectiveness of the system in the evaluation of electronic circuits for susceptibility to RF radiation. The system consists of a centralized data acquisition/control unit which interfaces with the equipment under test (EUT), the RF isolated field probes, and RF amplifier ALC output; four broadband linear RF amplifiers; and a frequency synthesizer with drive level increments in steps of 0.1 dB. Centralized control of the susceptibility test system is provided by a desktop computer. It is found that the system can reduce the execution time of RF susceptibility tests by as much as 70 percent. A block diagram of the system is provided.

Properties of radio-frequency heated argon confined uranium plasmas

NASA Technical Reports Server (NTRS)

1976-01-01

Pure uranium hexafluoride (UF6) was injected into an argon confined, steady state, rf-heated plasma within a fused silica peripheral wall test chamber. Exploratory tests conducted using an 80 kW rf facility and different test chamber flow configurations permitted selection of the configuration demonstrating the best confinement characteristics and minimum uranium compound wall coating. The overall test results demonstrated applicable flow schemes and associated diagnostic techniques were developed for the fluid mechanical confinement and characterization of uranium within an rf plasma discharge when pure UF6 is injected for long test times into an argon-confined, high-temperature, high-pressure, rf-heated plasma.

Estimating the diagnostic accuracy of rheumatoid factor in UK primary care: a study using the Clinical Practice Research Datalink.

PubMed

Miller, Anne; Nightingale, Alison L; Sammon, Cormac J; Mahtani, Kamal R; Holt, Tim A; McHugh, Neil J; Luqmani, Raashid A

2015-10-01

To investigate the diagnostic accuracy of RF as a test for RA in primary care and its impact on referral times using the Clinical Practice Research Datalink. We identified all patients with a first RF test recorded in the Clinical Practice Research Datalink between 1 January 2000 and 31 December 2008 and those diagnosed with RA within 2 years of testing. We calculated likelihood ratios (LRs), sensitivity, specificity and predictive values of RF for a diagnosis of RA. We compared time to hospital referral in those testing positive and negative using Kaplan-Meier failure curves and log-rank tests. Of 62 436 first RF tests, 4679 (7.5%) were positive. There were 1753 incident cases of RA, of which 57.8% were seropositive. The positive LR for RF was 9.5 (95% CI 9.0, 10.0) and the negative LR was 0.5 (95% CI 0.4, 0.5). Sensitivity and specificity were 57.8% (95% CI 55.4%, 60.1%) and 93.9% (95% CI 93.7%, 94.1%) and the positive predictive value and negative predictive value were 21.4% (95% CI 20.3%, 22.6%) and 98.7% (95% CI 98.6%, 98.8%), respectively. Median time to first hospital contact after the first RF test in those with seropositive vs seronegative results was 54 days (95% CI 49, 58) vs 150 (95% CI 147, 152). Only 2.8% of patients undergoing RF testing were diagnosed with RA, suggesting that RF is used to screen patients with musculoskeletal symptoms rather than those with more specific features of RA. A positive RF test may be helpful in diagnosing RA in primary care but performs badly in excluding RA and may delay referral. © The Author 2015. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

JET (3He)-D scenarios relying on RF heating: survey of selected recent experiments

NASA Astrophysics Data System (ADS)

Van Eester, D.; Lerche, E.; Andrew, Y.; Biewer, T. M.; Casati, A.; Crombé, K.; de la Luna, E.; Ericsson, G.; Felton, R.; Giacomelli, L.; Giroud, C.; Hawkes, N.; Hellesen, C.; Hjalmarsson, A.; Joffrin, E.; Källne, J.; Kiptily, V.; Lomas, P.; Mantica, P.; Marinoni, A.; Mayoral, M.-L.; Ongena, J.; Puiatti, M.-E.; Santala, M.; Sharapov, S.; Valisa, M.; JET EFDA contributors

2009-04-01

Recent JET experiments have been devoted to the study of (3He)-D plasmas involving radio frequency (RF) heating. This paper starts by discussing the RF heating efficiency theoretically expected in such plasmas, covering both relevant aspects of wave and of particle dynamics. Then it gives a concise summary of the main conclusions drawn from recent experiments that were either focusing on studying RF heating physics aspects or that were adopting RF heating as a tool to study plasma behavior. Depending on the minority concentration chosen, different physical phenomena are observed. At very low concentration (X[3He] < 1%), energetic tails are formed which trigger MHD activity and result in loss of fast particles. Alfvén cascades were observed and gamma ray tomography indirectly shows the impact of sawtooth crashes on the fast particle orbits. Low concentration (X[3He] < 10%) favors minority heating while for X[3He] Gt 10% electron mode conversion damping becomes dominant. Evidence for the Fuchs et al standing wave effect (Fuchs et al 1995 Phys. Plasmas 2 1637-47) on the absorption is presented. RF induced deuterium tails were observed in mode conversion experiments with large X[3He] (≈18%). As tentative modeling shows, the formation of these tails can be explained as a consequence of wave power absorption by neutral beam particles that efficiently interact with the waves well away from the cold D cyclotron resonance position as a result of their substantial Doppler shift. As both ion and electron RF power deposition profiles in (3He)-D plasmas are fairly narrow—giving rise to localized heat sources—the RF heating method is an ideal tool for performing transport studies. Various of the experiments discussed here were done in plasmas with internal transport barriers (ITBs). ITBs are identified as regions with locally reduced diffusivity, where poloidal spinning up of the plasma is observed. The present know-how on the role of RF heating for impurity transport is also briefly summarized.

Characterization of an Outdoor Ambient Radio Frequency Environment

DTIC Science & Technology

2016-02-16

radio frequency noise ”) prior to testing of a specific system under test (SUT). With this characterization, locations can be selected to avoid RF...spectrum analyzer, ambient RF noise floor, RF interference 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT SAR 18...environment (sometimes referred to as “radio frequency noise ”) prior to testing of a specific system under test (SUT). With this characterization

Test Result of 650 MHz, Beta 0.61 Single Cell Niobium Cavity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seth, Sudeshna; Bhattacharyya, Pranab; Dutta Gupta, Anjan

VECC has been involved in the design, analysis and development of 650 MHz, beta 0.61 (LB650), elliptical Superconducting RF linac cavity, as part of research and development activities on SRF cavities and associated technologies under Indian Institutions Fermilab Collaboration (IIFC). A single-cell niobium cavity has been indigenously designed and developed at VECC, with the help of Electron Beam Welding (EBW) facility at IUAC, New Delhi. Various measurements, processing and testing at 2K in Vertical Test Stand (VTS) of the single-cell cavity was carried out at ANL and Fermilab, USA, with active participation of VECC engineers. It achieved a maximum acceleratingmore » gradient(Eacc) of 34.5 MV/m with Quality Factor of 2·10⁹ and 30 MV/m with Quality Factor of 1.5·10¹⁰. This is probably the highest accelerating gradient achieved so far in the world for LB650 cavities. This paper describes the design, fabrication and measurement of the single cell niobium cavity. Cavity processing and test results of Vertical Test of the single-cell niobium cavity are also presented.« less

Plasma core reactor simulations using RF uranium seeded argon discharges

NASA Technical Reports Server (NTRS)

Roman, W. C.

1975-01-01

An experimental investigation was conducted using the United Technologies Research Center (UTRC) 80 kW and 1.2 MW RF induction heater systems to aid in developing the technology necessary for designing a self-critical fissioning uranium plasma core reactor (PCR). A nonfissioning, steady-state RF-heated argon plasma seeded with pure uranium hexafluoride (UF6) was used. An overall objective was to achieve maximum confinement of uranium vapor within the plasma while simultaneously minimizing the uranium compound wall deposition. Exploratory tests were conducted using the 80 kW RF induction heater with the test chamber at approximately atmospheric pressure and discharge power levels on the order of 10 kW. Four different test chamber flow configurations were tested to permit selection of the configuration offering the best confinement characteristics for subsequent tests at higher pressure and power in the 1.2 MW RF induction heater facility.

Fast shut-down protection system for radio frequency breakdown and multipactor testing.

PubMed

Graves, T P; Hanson, P; Michaelson, J M; Farkas, A D; Hubble, A A

2014-02-01

Radio frequency (RF) breakdown such as multipactor or ionization breakdown is a device-limiting phenomenon for on-orbit spacecraft used for communication, navigation, or other RF payloads. Ground testing is therefore part of the qualification process for all high power components used in these space systems. This paper illustrates a shut-down protection system to be incorporated into multipactor/ionization breakdown ground testing for susceptible RF devices. This 8 channel system allows simultaneous use of different diagnostic classes and different noise floors. With initiation of a breakdown event, diagnostic signals increase above a user-specified level, which then opens an RF switch to eliminate RF power from the high power amplifier. Examples of this system in use are shown for a typical setup, illustrating the reproducibility of breakdown threshold voltages and the lack of multipactor conditioning. This system can also be utilized to prevent excessive damage to RF components in tests with sensitive or flight hardware.

SITE project. Phase 1: Continuous data bit-error-rate testing

NASA Technical Reports Server (NTRS)

Fujikawa, Gene; Kerczewski, Robert J.

1992-01-01

The Systems Integration, Test, and Evaluation (SITE) Project at NASA LeRC encompasses a number of research and technology areas of satellite communications systems. Phase 1 of this project established a complete satellite link simulator system. The evaluation of proof-of-concept microwave devices, radiofrequency (RF) and bit-error-rate (BER) testing of hardware, testing of remote airlinks, and other tests were performed as part of this first testing phase. This final report covers the test results produced in phase 1 of the SITE Project. The data presented include 20-GHz high-power-amplifier testing, 30-GHz low-noise-receiver testing, amplitude equalization, transponder baseline testing, switch matrix tests, and continuous-wave and modulated interference tests. The report also presents the methods used to measure the RF and BER performance of the complete system. Correlations of the RF and BER data are summarized to note the effects of the RF responses on the BER.

Measured performance of the GTA rf systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Denney, P.M.; Jachim, S.P.

1993-06-01

This paper describes the performance of the RF systems on the Ground Test Accelerator (GTA). The RF system architecture is briefly described. Among the RF performance results presented are RF field flatness and stability, amplitude and phase control resolution, and control system bandwidth and stability. The rejection by the RF systems of beam-induced disturbances, such as transients and noise, are analyzed. The observed responses are also compared to computer-based simulations of the RF systems for validation.

Measured performance of the GTA rf systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Denney, P.M.; Jachim, S.P.

1993-01-01

This paper describes the performance of the RF systems on the Ground Test Accelerator (GTA). The RF system architecture is briefly described. Among the RF performance results presented are RF field flatness and stability, amplitude and phase control resolution, and control system bandwidth and stability. The rejection by the RF systems of beam-induced disturbances, such as transients and noise, are analyzed. The observed responses are also compared to computer-based simulations of the RF systems for validation.

An electromyographic analysis of selected asana in experienced yogic practitioners.

PubMed

Kelley, Kathleen; Slattery, Katherine; Apollo, Kaitlyn

2018-01-01

The purpose of this study was to assess electromyographic (EMG) output of the anterior tibialis (TA), medial head of the gastrocnemius (GA), rectus femoris (RF), bicep femoris (BF), and gluteus medius (GM) in experienced yogic practitioners during selected yoga asana. A secondary purpose was to examine the differences in EMG output in unilateral V. bilateral standing yoga asana. The study was a single occasion descriptive design. Thirteen healthy yoga practitioners (1 male, 12 females, average age of 37.5) with more than five years of experience were recruited. EMG activity was recorded during maximum voluntary isometric contractions (MVIC) of the TA, GA, RF, and BF using the Biodex Multijoint System ® , and GM using manual muscle testing position. Subjects then performed the following yoga asana while EMG activity was recorded: downward facing dog, half-moon, tree, chair, and warrior three pose. Each asana was held for fifteen seconds and performed three times. EMG data were band pass filtered and the root mean square was obtained. Asana data were then amplitude normalized with the subjects' MVIC data. Integrated EMG was calculated for TA, GA, RF, BF and GM, in each asana. A multilevel regression analysis was performed, and peak EMG data was compared. Analysis between muscles showed that during CH and DD EMG activity was greatest in the TA muscle compared to the other muscles, while during HM and WR the GA muscle showed the greatest activity. Analysis within muscles showed low GA, BF, and GM activity during chair pose and downward facing dog compared to half moon, tree, and warrior three, and high RF activity during chair compared to the other poses. In conclusion, there were differences in frontal and sagittal plane muscle activation between single limb and double limb poses in experienced yogic practitioners. Copyright © 2017. Published by Elsevier Ltd.

Associations between MMPI-2-RF validity scale scores and extra-test measures of personality and psychopathology.

PubMed

Forbey, Johnathan D; Lee, Tayla T C; Ben-Porath, Yossef S; Arbisi, Paul A; Gartland, Diane

2013-08-01

The current study explored associations between two potentially invalidating self-report styles detected by the Validity scales of the Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF), over-reporting and under-reporting, and scores on the MMPI-2-RF substantive, as well as eight collateral self-report measures administered either at the same time or within 1 to 10 days of MMPI-2-RF administration. Analyses were conducted with data provided by college students, male prisoners, and male psychiatric outpatients from a Veterans Administration facility. Results indicated that if either an over- or under-reporting response style was suggested by the MMPI-2-RF Validity scales, scores on the majority of the MMPI-2-RF substantive scales, as well as a number of collateral measures, were significantly affected in all three groups in the expected directions. Test takers who were identified as potentially engaging in an over- or under-reporting response style by the MMPI-2-RF Validity scales appeared to approach extra-test measures similarly regardless of when these measures were administered in relation to the MMPI-2-RF. Limitations and suggestions for future study are discussed.

Fabrication and radio frequency test of large-area MgB 2 films on niobium substrates

DOE PAGES

Ni, Zhimao; Guo, Xin; Welander, Paul B.; ...

2017-01-19

Magnesium diboride (MgB 2) is a promising candidate material for superconducting radio frequency (RF) cavities because of its higher transition temperature and critical field compared with niobium. To meet the demand of RF test devices, the fabrication of large-area MgB 2 films on metal substrates is needed. Here, in this work, high quality MgB 2 films with 50 mm diameter were fabricated on niobium by using an improved HPCVD system at Peking University, and RF tests were carried out at SLAC National Accelerator Laboratory. The transition temperature is approximately 39.6 K and the RF surface resistance is about 120 μΩmore » at 4 K and 11.4 GHz. Finally, the fabrication processes, surface morphology, DC superconducting properties and RF tests of these large-area MgB 2 films are presented.« less

Fabrication and radio frequency test of large-area MgB 2 films on niobium substrates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ni, Zhimao; Guo, Xin; Welander, Paul B.

Magnesium diboride (MgB 2) is a promising candidate material for superconducting radio frequency (RF) cavities because of its higher transition temperature and critical field compared with niobium. To meet the demand of RF test devices, the fabrication of large-area MgB 2 films on metal substrates is needed. Here, in this work, high quality MgB 2 films with 50 mm diameter were fabricated on niobium by using an improved HPCVD system at Peking University, and RF tests were carried out at SLAC National Accelerator Laboratory. The transition temperature is approximately 39.6 K and the RF surface resistance is about 120 μΩmore » at 4 K and 11.4 GHz. Finally, the fabrication processes, surface morphology, DC superconducting properties and RF tests of these large-area MgB 2 films are presented.« less

Assessing the use of Quantitative Light-induced Fluorescence-Digital as a clinical plaque assessment.

PubMed

Han, Sun-Young; Kim, Bo-Ra; Ko, Hae-Youn; Kwon, Ho-Keun; Kim, Baek-Il

2016-03-01

The aims of this study were to compare the relationship between red fluorescent plaque (RF plaque) area by Quantitative Light-induced Fluorescence-Digital (QLF-D) and disclosed plaque area by two-tone disclosure, and to assess the bacterial composition of the RF plaque by real time-PCR. Fifty healthy subjects were included and 600 facial surfaces of their anterior teeth were examined. QLF-D was taken on two separate occasions (before and after disclosing), and the RF plaque area was calculated based on Plaque Percent Index (PPI). After disclosing, the stained plaque area was analyzed to investigate the relationship with the RF plaque area. The relationship was evaluated using Pearson correlation and paired t-test. Then, the RF and non-red fluorescent (non-RF) plaque samples were obtained from the same subject for real-time PCR test. Total 10 plaque samples were compared the ratio of the 6 of bacteria using Wilcoxon signed rank test. Regarding the paired t-test, the blue-staining plaque area (9.3±9.2) showed significantly similarity with the RF plaque area (9.1±14.9, p=0.80) at ΔR20, however, the red-staining plaque area (31.6±20.9) presented difference from the RF plaque area (p<0.0001). In addition, bacterial composition of Prevotella intermedia and Streptococcus anginosus was associated with substantially more the RF plaque than the non-RF plaque (p<0.05). The plaque assessment method using QLF-D has potential to detect mature plaque, and the plaque area was associated with the blue-staining area using two-tone disclosure. Copyright © 2015 Elsevier B.V. All rights reserved.

Low-cost TDRSS communications for NASA's long duration balloon project

NASA Technical Reports Server (NTRS)

Israel, David J.

1993-01-01

A new transponder and RF ground support equipment for the NASA Tracking and Data Relay Satellite System (TDRSS) intended to support long duration scientific balloon flights in Antarctica are described. The new balloon class transponder features a highly integrated spread spectrum receiver design based on programmable charge coupled device (CCD) correlators and digital signal processing chips. The correlator chip is a Lincoln Labs 4ABC with four CCD channels. The balloon transponder is capable of reporting an estimate of its input bit error rate using digital signal processing. The TDRSS user RF test set is based on a set of RF ground support equipment capable of providing both the RF communications and direct control and monitoring necessary for transponder testing and a two-way RF link for preflight testing.

Plasma core reactor simulations using RF uranium seeded argon discharges

NASA Technical Reports Server (NTRS)

Roman, W. C.

1976-01-01

Experimental results are described in which pure uranium hexafluoride was injected into an argon-confined, steady-state, RF-heated plasma to investigate characteristics of plasma core nuclear reactors. The 80 kW (13.56 MHz) and 1.2 MW (5.51 MHz) rf induction heater facilities were used to determine a test chamber flow scheme which offered best uranium confinement with minimum wall coating. The cylindrical fused-silica test chamber walls were 5.7-cm-ID by 10-cm-long. Test conditions included RF powers of 2-85 kW, chamber pressures of 1-12 atm, and uranium hexafluoride mass-flow rates of 0.005-0.13 g/s. Successful techniques were developed for fluid-mechanical confinement of RF-heated plasmas with pure uranium hexafluoride injection.

Rheumatoid factor testing in Spanish primary care: A population-based cohort study including 4.8 million subjects and almost half a million measurements.

PubMed

Morsley, Klara; Miller, Anne; Luqmani, Raashid; Fina-Aviles, Francesc; Javaid, Muhammad Kassim; Edwards, Christopher J; Pinedo-Villanueva, Rafael; Medina, Manuel; Calero, Sebastian; Cooper, Cyrus; Arden, Nigel; Prieto-Alhambra, Daniel

2018-02-26

Rheumatoid factor (RF) testing is used in primary care in the diagnosis of rheumatoid arthritis (RA); however a positive RF may occur without RA. Incorrect use of RF testing may lead to increased costs and delayed diagnoses. The aim was to assess the performance of RF as a test for RA and to estimate the costs associated with its use in a primary care setting. A retrospective cohort study using the Information System for the Development of Research in Primary Care database (contains primary care records and laboratory results of >80% of the Catalonian population, Spain). Participants were patients ≥18 years with ≥1 RF test performed between 01/01/2006 and 31/12/2011, without a pre-existing diagnosis of RA. Outcome measures were an incident diagnosis of RA within 1 year of testing, and the cost of testing per case of RA. 495,434/4,796,498 (10.3%) patients were tested at least once. 107,362 (21.7%) of those tested were sero-positive of which 2768 (2.6%) were diagnosed with RA within 1 year as were 1141/388,072 (0.3%) sero-negative participants. The sensitivity of RF was 70.8% (95% CI 69.4-72.2), specificity 78.7% (78.6-78.8), and positive and negative predictive values 2.6% (2.5-2.7) and 99.7% (99.6-99.7) respectively. Approximately €3,963,472 was spent, with a cost of €1432 per true positive case. Although 10% of patients were tested for RF, most did not have RA. Limiting testing to patients with a higher pre-test probability would significantly reduce the cost of testing. Copyright © 2017 Elsevier España, S.L.U. and Sociedad Española de Reumatología y Colegio Mexicano de Reumatología. All rights reserved.

RF Performance of Membrane Aperture Shells

NASA Technical Reports Server (NTRS)

Flint, Eirc M.; Lindler, Jason E.; Thomas, David L.; Romanofsky, Robert

2007-01-01

This paper provides an overview of recent results establishing the suitability of Membrane Aperture Shell Technology (MAST) for Radio Frequency (RF) applications. These single surface shells are capable of maintaining their figure with no preload or pressurization and minimal boundary support, yet can be compactly roll stowed and passively self deploy. As such, they are a promising technology for enabling a future generation of RF apertures. In this paper, we review recent experimental and numerical results quantifying suitable RF performance. It is shown that candidate materials possess metallic coatings with sufficiently low surface roughness and that these materials can be efficiently fabricated into RF relevant doubly curved shapes. A numerical justification for using a reflectivity metric, as opposed to the more standard RF designer metric of skin depth, is presented and the resulting ability to use relatively thin coating thickness is experimentally validated with material sample tests. The validity of these independent film sample measurements are then confirmed through experimental results measuring RF performance for reasonable sized doubly curved apertures. Currently available best results are 22 dBi gain at 3 GHz (S-Band) for a 0.5m aperture tested in prime focus mode, 28dBi gain for the same antenna in the C-Band (4 to 6 GHz), and 36.8dBi for a smaller 0.25m antenna tested at 32 GHz in the Ka-Band. RF range test results for a segmented aperture (one possible scaling approach) are shown as well. Measured antenna system actual efficiencies (relative to the unachievable) ideal for these on axis tests are generally quite good, typically ranging from 50 to 90%.

Analysis of the bending stiffness and adhesion effect in RF-MEMS structures

NASA Astrophysics Data System (ADS)

Birleanu, C.; Pustan, M.; Dudescu, C.; Merie, V.; Pintea, I.

2017-02-01

Microelectromechanical system (MEMS) is a special branch with a wide range of applications in sensing, switching and actuating devices. Designing the reliable MEMS for thin free-standing structures like as bridges and cantilevers requires understanding of the tribomechanical properties of the materials and structures. The effect of geometrical dimensions (cross-section dimensions and length) on mechanical and tribological behavior of free-standing MEMS structures made of electroplated gold was analyzed in this paper. Special attention was given to the dependences between stiffness and cantilever length and the dependences between bending stress and variable travel range of actuated load. The force position was moved from the beams free-end toward to the anchor. The tests were performed at room temperature (22°C) and relative humidity RH of 40% with a noise- and vibration-isolated and environment-controlled XE-70 AFM from Park Systems using the contact mode. Each measurement was repeated many times in order to improve the accuracy of the experimental results. The stiffness of a microcantilever varies if the position of the acting force is changed. The experimental results obtained were in good correlation with those obtained analytically.

A comparison of selected parametric and imputation methods for estimating snag density and snag quality attributes

USGS Publications Warehouse

Eskelson, Bianca N.I.; Hagar, Joan; Temesgen, Hailemariam

2012-01-01

Snags (standing dead trees) are an essential structural component of forests. Because wildlife use of snags depends on size and decay stage, snag density estimation without any information about snag quality attributes is of little value for wildlife management decision makers. Little work has been done to develop models that allow multivariate estimation of snag density by snag quality class. Using climate, topography, Landsat TM data, stand age and forest type collected for 2356 forested Forest Inventory and Analysis plots in western Washington and western Oregon, we evaluated two multivariate techniques for their abilities to estimate density of snags by three decay classes. The density of live trees and snags in three decay classes (D1: recently dead, little decay; D2: decay, without top, some branches and bark missing; D3: extensive decay, missing bark and most branches) with diameter at breast height (DBH) ≥ 12.7 cm was estimated using a nonparametric random forest nearest neighbor imputation technique (RF) and a parametric two-stage model (QPORD), for which the number of trees per hectare was estimated with a Quasipoisson model in the first stage and the probability of belonging to a tree status class (live, D1, D2, D3) was estimated with an ordinal regression model in the second stage. The presence of large snags with DBH ≥ 50 cm was predicted using a logistic regression and RF imputation. Because of the more homogenous conditions on private forest lands, snag density by decay class was predicted with higher accuracies on private forest lands than on public lands, while presence of large snags was more accurately predicted on public lands, owing to the higher prevalence of large snags on public lands. RF outperformed the QPORD model in terms of percent accurate predictions, while QPORD provided smaller root mean square errors in predicting snag density by decay class. The logistic regression model achieved more accurate presence/absence classification of large snags than the RF imputation approach. Adjusting the decision threshold to account for unequal size for presence and absence classes is more straightforward for the logistic regression than for the RF imputation approach. Overall, model accuracies were poor in this study, which can be attributed to the poor predictive quality of the explanatory variables and the large range of forest types and geographic conditions observed in the data.

Predicting live and dead tree basal area of bark beetle affected forests from discrete-return lidar

Treesearch

Benjamin C. Bright; Andrew T. Hudak; Robert McGaughey; Hans-Erik Andersen; Jose Negron

2013-01-01

Bark beetle outbreaks have killed large numbers of trees across North America in recent years. Lidar remote sensing can be used to effectively estimate forest biomass, but prediction of both live and dead standing biomass in beetle-affected forests using lidar alone has not been demonstrated. We developed Random Forest (RF) models predicting total, live, dead, and...

Evaluation of a role functioning computer adaptive test (RF-CAT).

PubMed

Anatchkova, M; Rose, M; Ware, J; Bjorner, J B

2013-06-01

To evaluate the validity and participants' acceptance of an online assessment of role function using computer adaptive test (RF-CAT). The RF-CAT and a set of established quality of life instruments were administered in a cross-sectional study in a panel sample (n = 444) recruited from the general population with over-selection of participants with selected self-report chronic conditions (n = 225). The efficiency, score accuracy, validity, and acceptability of the RF-CAT were evaluated and compared to existing measures. The RF-CAT with a stopping rule of six items with content balancing used 25 of the available bank items and was completed on average in 66 s. RF-CAT and the legacy tools scores were highly correlated (.64-.84) and successfully discriminated across known groups. The RF-CAT produced a more precise assessment over a wider range than the SF-36 Role Physical scale. Patients' evaluations of the RF-CAT system were positive overall, with no differences in ratings observed between the CAT and static assessments. The RF-CAT was feasible, more precise than the static SF-36 RP and equally acceptable to participants as legacy measures. In empirical tests of validity, the better performance of the CAT was not uniformly statistically significant. Further research exploring the relationship between gained precision and discriminant power of the CAT assessment is needed.

Machining and brazing of accelerating RF cavity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ghodke, S.R.; Barnwal, Rajesh; Mondal, Jayant, E-mail: ghodke_barc@yahoo.co.in

2014-07-01

BARC has developed 2856 MHz accelerating cavities for 6 MeV, 9 MeV and 10 MeV RF Linac. New vendors are developed for mass production of accelerating cavity for future projects. New vendors are developing for diamond turning machining, cleaning and brazing processes. Fabrication involved material testing, CNC diamond turning of cavity, cavity cleaning and brazing. Before and after brazing resonance frequency (RF) of cavity was checked with vector network analyser (VNA). A power feed test setup is also fabricated to test power feed cavity before brazing. This test setup will be used to find out assembly performance of power feedmore » cavity and its coupler. This paper discusses about nano machining, cleaning and brazing processes of RF cavities. (author)« less

An RF phased array applicator designed for hyperthermia breast cancer treatments

PubMed Central

Wu, Liyong; McGough, Robert J; Arabe, Omar Ali; Samulski, Thaddeus V

2007-01-01

An RF phased array applicator has been constructed for hyperthermia treatments in the intact breast. This RF phased array consists of four antennas mounted on a Lexan water tank, and geometric focusing is employed so that each antenna points in the direction of the intended target. The operating frequency for this phased array is 140 MHz. The RF array has been characterized both by electric field measurements in a water tank and by electric field simulations using the finite-element method. The finite-element simulations are performed with HFSS software, where the mesh defined for finite-element calculations includes the geometry of the tank enclosure and four end-loaded dipole antennas. The material properties of the water tank enclosure and the antennas are also included in each simulation. The results of the finite-element simulations are compared to the measured values for this configuration, and the results, which include the effects of amplitude shading and phase shifting, show that the electric field predicted by finite-element simulations is similar to the measured field. Simulations also show that the contributions from standing waves are significant, which is consistent with measurement results. Simulated electric field and bio-heat transfer results are also computed within a simple 3D breast model. Temperature simulations show that, although peak temperatures are generated outside the simulated tumour target, this RF phased array applicator is an effective device for regional hyperthermia in the intact breast. PMID:16357427

Extending fullwave core ICRF simulation to SOL and antenna regions using FEM solver

NASA Astrophysics Data System (ADS)

Shiraiwa, S.; Wright, J. C.

2016-10-01

A full wave simulation approach to solve a driven RF waves problem including hot core, SOL plasmas and possibly antenna is presented. This approach allows for exploiting advantages of two different way of representing wave field, namely treating spatially dispersive hot conductivity in a spectral solver and handling complicated geometry in SOL/antenna region using an unstructured mesh. Here, we compute a mode set in each region with the RF electric field excitation on the connecting boundary between core and edge regions. A mode corresponding to antenna excitation is also computed. By requiring the continuity of tangential RF electric and magnetic fields, the solution is obtained as unique superposition of these modes. In this work, TORIC core spectral solver is modified to allow for mode excitation, and the edge region of diverted Alcator C-Mod plasma is modeled using COMSOL FEM package. The reconstructed RF field is similar in the core region to TORIC stand-alone simulation. However, it contains higher poloidal modes near the edge and captures a wave bounced and propagating in the poloidal direction near the vacuum-plasma boundary. These features could play an important role when the single power pass absorption is modest. This new capability will enable antenna coupling calculations with a realistic load plasma, including collisional damping in realistic SOL plasma and other loss mechanisms such as RF sheath rectification. USDoE Awards DE-FC02-99ER54512, DE-FC02-01ER54648.

The Hyper-X Antenna Radiation Pattern Tests and Radio Frequency System Redesign

NASA Technical Reports Server (NTRS)

Hodge, Mark W.; Kelley, John W.

2006-01-01

Testing was performed to determine the antenna radiation pattern measurements of the Hyper-X, X-43 ship 2 aircraft. One test was conducted at the Air Force Flight Test Center (AFFTC) Benefield Anechoic Facility (BAF) on January 24-January 27, 2000. A second test was done at MicroCraft in Tullahoma Tennessee by the Naval Air Weapons Center (NAWC) China Lake, California on September 8, 2001. The overall test objective was to gather qualitative antenna radiation pattern data from installed antennas on the HXRV. This objective was accomplished by collecting antenna radiation patterns at selected elevations of the HXRV. The test data was used to identify areas of RF coverage and assist in positioning the P-3 aircraft for best RF reception. The antenna pattern data presented nulls and possible low RF reception areas around the aircraft. This led to a redesign of the RF system. The redesigned system provided redundancy in case a telemetry transmitter should fail. The redesign provided more complete RF coverage within the antenna's capabilities. A second look at the flight path and necessary data collection led to a change in the beacon transponder system.

Addressing challenges to MMPI-2-RF-based testimony: questions and answers.

PubMed

Ben-Porath, Yossef S

2012-11-01

Introduction of a new version of a psychological test brings with it challenges that can be accentuated by the adversarial nature of the legal process. In the case of the Minnesota Multiphasic Personality Inventory-2 Restructured Form (MMPI-2-RF), these challenges can be addressed by becoming familiar with the rationale for and the methods used in revising the inventory, the information contained in the test manuals, and the growing peer-reviewed literature on the test. Potential challenges to MMPI-2-RF-based testimony are identified in this article and discussed in question and answer format. The questions guiding this discussion are based on the Daubert factors, established in 1993 by the US Supreme Court as criteria for gauging the scientific validity of proffered expert testimony. The answers to these questions apply more broadly to testimony in depositions, pre-trial hearings, and at trial. Consideration of the MMPI-2-RF in light of the Daubert factors indicates that the instrument has been subjected to extensive empirical testing and that a substantial peer-reviewed literature is available to guide and support its use. Information about the known and potential rate of error associated with MMPI-2-RF scores is available, and standard procedures for administration, scoring, and interpretation of the inventory are detailed in the test administration manual. Indicators of MMPI-2-RF acceptance can be cited, and criticisms of the MMPI-2-RF can be addressed with information available in the test documents and an extensive, modern, and actively growing peer-reviewed literature.

Modeling biophysical properties of broad-leaved stands in the hyrcanian forests of Iran using fused airborne laser scanner data and ultraCam-D images

NASA Astrophysics Data System (ADS)

Mohammadi, Jahangir; Shataee, Shaban; Namiranian, Manochehr; Næsset, Erik

2017-09-01

Inventories of mixed broad-leaved forests of Iran mainly rely on terrestrial measurements. Due to rapid changes and disturbances and great complexity of the silvicultural systems of these multilayer forests, frequent repetition of conventional ground-based plot surveys is often cost prohibitive. Airborne laser scanning (ALS) and multispectral data offer an alternative or supplement to conventional inventories in the Hyrcanian forests of Iran. In this study, the capability of a combination of ALS and UltraCam-D data to model stand volume, tree density, and basal area using random forest (RF) algorithm was evaluated. Systematic sampling was applied to collect field plot data on a 150 m × 200 m sampling grid within a 1100 ha study area located at 36°38‧- 36°42‧N and 54°24‧-54°25‧E. A total of 308 circular plots (0.1 ha) were measured for calculation of stand volume, tree density, and basal area per hectare. For each plot, a set of variables was extracted from both ALS and multispectral data. The RF algorithm was used for modeling of the biophysical properties using ALS and UltraCam-D data separately and combined. The results showed that combining the ALS data and UltraCam-D images provided a slight increase in prediction accuracy compared to separate modeling. The RMSE as percentage of the mean, the mean difference between observed and predicted values, and standard deviation of the differences using a combination of ALS data and UltraCam-D images in an independent validation at 0.1-ha plot level were 31.7%, 1.1%, and 84 m3 ha-1 for stand volume; 27.2%, 0.86%, and 6.5 m2 ha-1 for basal area, and 35.8%, -4.6%, and 77.9 n ha-1 for tree density, respectively. Based on the results, we conclude that fusion of ALS and UltraCam-D data may be useful for modeling of stand volume, basal area, and tree density and thus gain insights into structural characteristics in the complex Hyrcanian forests.

Langmuir probes for SPIDER (source for the production of ions of deuterium extracted from radio frequency plasma) experiment: Tests in BATMAN (Bavarian test machine for negative ions)

NASA Astrophysics Data System (ADS)

Brombin, M.; Spolaore, M.; Serianni, G.; Pomaro, N.; Taliercio, C.; Palma, M. Dalla; Pasqualotto, R.; Schiesko, L.

2014-11-01

A prototype system of the Langmuir probes for SPIDER (Source for the production of Ions of Deuterium Extracted from RF plasma) was manufactured and experimentally qualified. The diagnostic was operated in RF (Radio Frequency) plasmas with cesium evaporation on the BATMAN (BAvarian Test MAchine for Negative ions) test facility, which can provide plasma conditions as expected in the SPIDER source. A RF passive compensation circuit was realised to operate the Langmuir probes in RF plasmas. The sensors' holder, designed to better simulate the bias plate conditions in SPIDER, was exposed to a severe experimental campaign in BATMAN with cesium evaporation. No detrimental effect on the diagnostic due to cesium evaporation was found during the exposure to the BATMAN plasma and in particular the insulation of the electrodes was preserved. The paper presents the system prototype, the RF compensation circuit, the acquisition system (as foreseen in SPIDER), and the results obtained during the experimental campaigns.

Langmuir probes for SPIDER (Source for the production of Ions of Deuterium Extracted from Radio Frequency plasma) experiment: tests in BATMAN (BAvarian Test Machine for Negative ions).

PubMed

Brombin, M; Spolaore, M; Serianni, G; Pomaro, N; Taliercio, C; Dalla Palma, M; Pasqualotto, R; Schiesko, L

2014-11-01

A prototype system of the Langmuir probes for SPIDER (Source for the production of Ions of Deuterium Extracted from RF plasma) was manufactured and experimentally qualified. The diagnostic was operated in RF (Radio Frequency) plasmas with cesium evaporation on the BATMAN (BAvarian Test MAchine for Negative ions) test facility, which can provide plasma conditions as expected in the SPIDER source. A RF passive compensation circuit was realised to operate the Langmuir probes in RF plasmas. The sensors' holder, designed to better simulate the bias plate conditions in SPIDER, was exposed to a severe experimental campaign in BATMAN with cesium evaporation. No detrimental effect on the diagnostic due to cesium evaporation was found during the exposure to the BATMAN plasma and in particular the insulation of the electrodes was preserved. The paper presents the system prototype, the RF compensation circuit, the acquisition system (as foreseen in SPIDER), and the results obtained during the experimental campaigns.

Design development and testing of high voltage power supply with crowbar protection for IOT based RF amplifier system in VECC

NASA Astrophysics Data System (ADS)

Thakur, S. K.; Kumar, Y.

2018-05-01

This paper described the detailed design, development and testing of high voltage power supply (‑30 kV, 3.2 A) and different power supplies for biasing electrodes of Inductive Output Tube (IOT) based high power Radio Frequency (RF) amplifier. This IOT based RF amplifier is further used for pursuing research and development activity in superconducting RF cavity project at Variable Energy Cyclotron Centre (VECC) Kolkata. The state-of-the-art technology of IOT-based high power RF amplifier is designed, developed, and tested at VECC which is the first of its kind in India. A high voltage power supply rated at negative polarity of 30 kV dc/3.2 A is required for biasing cathode of IOT with crowbar protection circuit. This power supply along with crowbar protection system is designed, developed and tested at VECC for testing the complete setup. The technical difficulties and challenges occured during the design of cathode power supply, its crowbar protection techniques along with other supported power supplies i.e. grid and ion pump power supplies are discussed in this paper.

H- radio frequency source development at the Spallation Neutron Source.

PubMed

Welton, R F; Dudnikov, V G; Gawne, K R; Han, B X; Murray, S N; Pennisi, T R; Roseberry, R T; Santana, M; Stockli, M P; Turvey, M W

2012-02-01

The Spallation Neutron Source (SNS) now routinely operates nearly 1 MW of beam power on target with a highly persistent ∼38 mA peak current in the linac and an availability of ∼90%. H(-) beam pulses (∼1 ms, 60 Hz) are produced by a Cs-enhanced, multicusp ion source closely coupled with an electrostatic low energy beam transport (LEBT), which focuses the 65 kV beam into a radio frequency quadrupole accelerator. The source plasma is generated by RF excitation (2 MHz, ∼60 kW) of a copper antenna that has been encased with a thickness of ∼0.7 mm of porcelain enamel and immersed into the plasma chamber. The ion source and LEBT normally have a combined availability of ∼99%. Recent increases in duty-factor and RF power have made antenna failures a leading cause of downtime. This report first identifies the physical mechanism of antenna failure from a statistical inspection of ∼75 antennas which ran at the SNS, scanning electron microscopy studies of antenna surface, and cross sectional cuts and analysis of calorimetric heating measurements. Failure mitigation efforts are then described which include modifying the antenna geometry and our acceptance∕installation criteria. Progress and status of the development of the SNS external antenna source, a long-term solution to the internal antenna problem, are then discussed. Currently, this source is capable of delivering comparable beam currents to the baseline source to the SNS and, an earlier version, has briefly demonstrated unanalyzed currents up to ∼100 mA (1 ms, 60 Hz) on the test stand. In particular, this paper discusses plasma ignition (dc and RF plasma guns), antenna reliability, magnet overheating, and insufficient beam persistence.

Implementing New Methods of Laser Marking of Items in the Nuclear Material Control and Accountability System at SSC RF-IPPE: An Automated Laser Marking System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Regoushevsky, V I; Tambovtsev, S D; Dvukhsherstnov, V G

2009-05-18

For over ten years SSC RF-IPPE, together with the US DOE National Laboratories, has been working on implementing automated control and accountability methods for nuclear materials and other items. Initial efforts to use adhesive bar codes or ones printed (painted) onto metal revealed that these methods were inconvenient and lacked durability under operational conditions. For NM disk applications in critical stands, there is the additional requirement that labels not affect the neutron characteristics of the critical assembly. This is particularly true for the many stainless-steel clad disks containing highly enriched uranium (HEU) and plutonium that are used at SSC RF-IPPEmore » for modeling nuclear power reactors. In search of an alternate method for labeling these disks, we tested several technological options, including laser marking and two-dimensional codes. As a result, the method of laser coloring was chosen in combination with Data Matrix ECC200 symbology. To implement laser marking procedures for the HEU disks and meet all the nuclear material (NM) handling standards and rules, IPPE staff, with U.S. technical and financial support, implemented an automated laser marking system; there are also specially developed procedures for NM movements during laser marking. For the laser marking station, a Zenith 10F system by Telesis Technologies (10 watt Ytterbium Fiber Laser and Merlin software) is used. The presentation includes a flowchart for the automated system and a list of specially developed procedures with comments. Among other things, approaches are discussed for human-factor considerations. To date, markings have been applied to numerous steel-clad HEU disks, and the work continues. In the future this method is expected to be applied to other MC&A items.« less

ProGeRF: Proteome and Genome Repeat Finder Utilizing a Fast Parallel Hash Function

PubMed Central

Moraes, Walas Jhony Lopes; Rodrigues, Thiago de Souza; Bartholomeu, Daniella Castanheira

2015-01-01

Repetitive element sequences are adjacent, repeating patterns, also called motifs, and can be of different lengths; repetitions can involve their exact or approximate copies. They have been widely used as molecular markers in population biology. Given the sizes of sequenced genomes, various bioinformatics tools have been developed for the extraction of repetitive elements from DNA sequences. However, currently available tools do not provide options for identifying repetitive elements in the genome or proteome, displaying a user-friendly web interface, and performing-exhaustive searches. ProGeRF is a web site for extracting repetitive regions from genome and proteome sequences. It was designed to be efficient, fast, and accurate and primarily user-friendly web tool allowing many ways to view and analyse the results. ProGeRF (Proteome and Genome Repeat Finder) is freely available as a stand-alone program, from which the users can download the source code, and as a web tool. It was developed using the hash table approach to extract perfect and imperfect repetitive regions in a (multi)FASTA file, while allowing a linear time complexity. PMID:25811026

Ion velocities in the presheath of electronegative, radio-frequency plasmas measured by low-energy cutoff

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sobolewski, Mark A.; Wang, Yicheng; Goyette, Amanda

2016-07-11

Simple kinematic considerations indicate that, under certain conditions in radio-frequency (rf) plasmas, the amplitude of the low-energy peak in ion energy distributions (IEDs) measured at an electrode depends sensitively on ion velocities upstream, at the presheath/sheath boundary. By measuring this amplitude, the velocities at which ions exit the presheath can be determined and long-standing controversies regarding presheath transport can be resolved. Here, IEDs measured in rf-biased, inductively coupled plasmas in CF{sub 4} gas determined the presheath exit velocities of all significant positive ions: CF{sub 3}{sup +}, CF{sub 2}{sup +}, CF{sup +}, and F{sup +}. At higher bias voltages, we detectedmore » essentially the same velocity for all four ions. For all ions, measured velocities were significantly lower than the Bohm velocity and the electropositive ion sound speed. Neither is an accurate boundary condition for rf sheaths in electronegative gases: under certain low-frequency, high-voltage criteria defined here, either yields large errors in predicted IEDs. These results indicate that many widely used sheath models will need to be revised.« less

Electrostatic sensors for SPIDER experiment: Design, manufacture of prototypes, and first tests

NASA Astrophysics Data System (ADS)

Brombin, M.; Spolaore, M.; Serianni, G.; Barzon, A.; Franchin, L.; Pasqualotto, R.; Pomaro, N.; Schiesko, L.; Taliercio, C.; Trevisan, L.

2014-02-01

A system of electrostatic sensors has been designed for the SPIDER (Source for the production of Ions of Deuterium Extracted from RF plasma) experiment, prototype RF source of the ITER NBI (neutral beam injection). A prototype of the sensor system was manufactured and tested at the BATMAN (BAvarian Test MAchine for Negative ions) facility, where the plasma environment is similar to that of SPIDER. Different aspects concerning the mechanical manufacturing and the signal conditioning are presented, among them the RF compensation adopted to reduce the RF effects which could lead to overestimated values of the electron temperature. The first commissioning tests provided ion saturation current values in the range assumed for the design, so the deduced plasma density estimate is consistent with the expected values.

Electrostatic sensors for SPIDER experiment: design, manufacture of prototypes, and first tests.

PubMed

Brombin, M; Spolaore, M; Serianni, G; Barzon, A; Franchin, L; Pasqualotto, R; Pomaro, N; Schiesko, L; Taliercio, C; Trevisan, L

2014-02-01

A system of electrostatic sensors has been designed for the SPIDER (Source for the production of Ions of Deuterium Extracted from RF plasma) experiment, prototype RF source of the ITER NBI (neutral beam injection). A prototype of the sensor system was manufactured and tested at the BATMAN (BAvarian Test MAchine for Negative ions) facility, where the plasma environment is similar to that of SPIDER. Different aspects concerning the mechanical manufacturing and the signal conditioning are presented, among them the RF compensation adopted to reduce the RF effects which could lead to overestimated values of the electron temperature. The first commissioning tests provided ion saturation current values in the range assumed for the design, so the deduced plasma density estimate is consistent with the expected values.

Electrostatic sensors for SPIDER experiment: Design, manufacture of prototypes, and first tests

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brombin, M., E-mail: matteo.brombin@igi.cnr.it; Spolaore, M.; Serianni, G.

2014-02-15

A system of electrostatic sensors has been designed for the SPIDER (Source for the production of Ions of Deuterium Extracted from RF plasma) experiment, prototype RF source of the ITER NBI (neutral beam injection). A prototype of the sensor system was manufactured and tested at the BATMAN (BAvarian Test MAchine for Negative ions) facility, where the plasma environment is similar to that of SPIDER. Different aspects concerning the mechanical manufacturing and the signal conditioning are presented, among them the RF compensation adopted to reduce the RF effects which could lead to overestimated values of the electron temperature. The first commissioningmore » tests provided ion saturation current values in the range assumed for the design, so the deduced plasma density estimate is consistent with the expected values.« less

Improvements in Technique of NMR Imaging and NMR Diffusion Measurements in the Presence of Background Gradients.

NASA Astrophysics Data System (ADS)

Lian, Jianyu

In this work, modification of the cosine current distribution rf coil, PCOS, has been introduced and tested. The coil produces a very homogeneous rf magnetic field, and it is inexpensive to build and easy to tune for multiple resonance frequency. The geometrical parameters of the coil are optimized to produce the most homogeneous rf field over a large volume. To avoid rf field distortion when the coil length is comparable to a quarter wavelength, a parallel PCOS coil is proposed and discussed. For testing rf coils and correcting B _1 in NMR experiments, a simple, rugged and accurate NMR rf field mapping technique has been developed. The method has been tested and used in 1D, 2D, 3D and in vivo rf mapping experiments. The method has been proven to be very useful in the design of rf coils. To preserve the linear relation between rf output applied on an rf coil and modulating input for an rf modulating -amplifying system of NMR imaging spectrometer, a quadrature feedback loop is employed in an rf modulator with two orthogonal rf channels to correct the amplitude and phase non-linearities caused by the rf components in the rf system. The modulator is very linear over a large range and it can generate an arbitrary rf shape. A diffusion imaging sequence has been developed for measuring and imaging diffusion in the presence of background gradients. Cross terms between the diffusion sensitizing gradients and background gradients or imaging gradients can complicate diffusion measurement and make the interpretation of NMR diffusion data ambiguous, but these have been eliminated in this method. Further, the background gradients has been measured and imaged. A dipole random distribution model has been established to study background magnetic fields Delta B and background magnetic gradients G_0 produced by small particles in a sample when it is in a B_0 field. From this model, the minimum distance that a spin can approach a particle can be determined by measuring and <{bf G}_sp{0 }{2}>. From this model, the particle concentration in a sample can be determined by measuring the lineshape of a free induction decay (fid).

Association of anti-cyclic citrullinated peptide antibodies, anti-citrullin antibodies, and IgM and IgA rheumatoid factors with serological parameters of disease activity in rheumatoid arthritis.

PubMed

Greiner, Alexander; Plischke, Herbert; Kellner, Herbert; Gruber, Rudolf

2005-06-01

We evaluated the association of anti-cyclic citrullinated peptide (CCP) antibody titers with serological markers of disease activity. We also compared three different anti-CCP antibody ELISAs with an anti-citrullin ELISA and the IgM and the IgA rheumatoid factor (RF) in their performance of discriminating between rheumatoid arthritis (RA) and other rheumatic diseases. Sera from 333 consecutive patients of the Rheumaeinheit der Medizinischen Poliklinik Munchen, an outpatient clinic for rheumatic diseases, were collected and tested. Anti-CCP antibodies were assayed with three different commercially available ELISAs. Antifilaggrin antibodies were tested with a commercially available ELISA using in vitro deiminated recombinant rat filaggrin. IgA-RF was analyzed with an ELISA, whereas IgM-RF was measured by latex-enhanced turbidimetry. Rheumatoid arthritis (RA) was diagnosed in 87 patients according to the revised classification criteria of the American College of Rheumatology (ACR), probable RA was diagnosed in 23 patients in an early phase not (yet) fulfilling the ACR criteria, and 223 patients had other rheumatic diseases. Differences in sensitivity and specificity were calculated using McNemar's test. A measure of agreement (kappa statistic) was used to examine whether the tests tended to identify the same patients as positive or negative. Correlations between CCP titers and other tests were analyzed by Spearman nonparametric rank correlation. No significant differences in sensitivity and specificity were found between the tested CCP assays (80.0-80.9% and 97.3-98.1%, respectively). All three CCP tests were slightly but not significantly more sensitive and specific than the anti-citrullin assay (77% and 92%, respectively), comparably sensitive but significantly more specific compared with the IgM-RF (86% and 82%, respectively), and significantly more sensitive but comparably specific compared with the IgA-RF (63% and 94.4%, respectively) in detecting the patients with RA. There was no significant correlation between anti-CCP, anti-citrullin, or IgM-RF or IgA-RF antibody titers and C-reactive protein, erythrocyte sedimentation rate, or white blood cell count. A weak but significant linear correlation was found between anti-CCP titers and IgM-RF titers (r = 0.2, P = 0.03). We could not find a significant difference between the three tested anti-CCP assays and the anti-citrullin test in terms of sensitivity and specificity. Compared with the IgM-RF, all the anti-CCP assays were superior in specificity and comparable in sensitivity. Compared with the IgA-RF, they were more sensitive and comparably specific in the discrimination of patients with RA from other rheumatic diseases. No correlation of any tested autoantibody titer with serological parameters of inflammation was found.

Use of a radio frequency shield during 1.5 and 3.0 Tesla magnetic resonance imaging: experimental evaluation.

PubMed

Favazza, Christopher P; King, Deirdre M; Edmonson, Heidi A; Felmlee, Joel P; Rossman, Phillip J; Hangiandreou, Nicholas J; Watson, Robert E; Gorny, Krzysztof R

2014-01-01

Radiofrequency (RF) shields have been recently developed for the purpose of shielding portions of the patient's body during magnetic resonance imaging (MRI) examinations. We present an experimental evaluation of a commercially available RF shield in the MRI environment. All tests were performed on 1.5 T and 3.0 T clinical MRI scanners. The tests were repeated with and without the RF shield present in the bore, for comparison. Effects of the shield, placed within the scanner bore, on the RF fields generated by the scanner were measured directly using tuned pick-up coils. Attenuation, by as much as 35 dB, of RF field power was found inside the RF shield. These results were supported by temperature measurements of metallic leads placed inside the shield, in which no measurable RF heating was found. In addition, there was a small, simultaneous detectable increase (∼1 dB) of RF power just outside the edges of the shield. For these particular scanners, the autocalibrated RF power levels were reduced for scan locations prescribed just outside the edges of the shield, which corresponded with estimations based on the pick-up coil measurements. Additionally, no significant heating during MRI scanning was observed on the shield surface. The impact of the RF shield on the RF fields inside the magnet bore is likely to be dependent on the particular model of the RF shield or the MRI scanner. These results suggest that the RF shield could be a valuable tool for clinical MRI practices.

Use of a radio frequency shield during 1.5 and 3.0 Tesla magnetic resonance imaging: experimental evaluation

PubMed Central

Favazza, Christopher P; King, Deirdre M; Edmonson, Heidi A; Felmlee, Joel P; Rossman, Phillip J; Hangiandreou, Nicholas J; Watson, Robert E; Gorny, Krzysztof R

2014-01-01

Radiofrequency (RF) shields have been recently developed for the purpose of shielding portions of the patient’s body during magnetic resonance imaging (MRI) examinations. We present an experimental evaluation of a commercially available RF shield in the MRI environment. All tests were performed on 1.5 T and 3.0 T clinical MRI scanners. The tests were repeated with and without the RF shield present in the bore, for comparison. Effects of the shield, placed within the scanner bore, on the RF fields generated by the scanner were measured directly using tuned pick-up coils. Attenuation, by as much as 35 dB, of RF field power was found inside the RF shield. These results were supported by temperature measurements of metallic leads placed inside the shield, in which no measurable RF heating was found. In addition, there was a small, simultaneous detectable increase (∼1 dB) of RF power just outside the edges of the shield. For these particular scanners, the autocalibrated RF power levels were reduced for scan locations prescribed just outside the edges of the shield, which corresponded with estimations based on the pick-up coil measurements. Additionally, no significant heating during MRI scanning was observed on the shield surface. The impact of the RF shield on the RF fields inside the magnet bore is likely to be dependent on the particular model of the RF shield or the MRI scanner. These results suggest that the RF shield could be a valuable tool for clinical MRI practices. PMID:25378957

Beam-Switch Transient Effects in the RF Path of the ICAPA Receive Phased Array Antenna

NASA Technical Reports Server (NTRS)

Sands, O. Scott

2003-01-01

When the beam of a Phased Array Antenna (PAA) is switched from one pointing direction to another, transient effects in the RF path of the antenna are observed. Testing described in the report has revealed implementation-specific transient effects in the RF channel that are associated with digital clocking pulses that occur with transfer of data from the Beam Steering Controller (BSC) to the digital electronics of the PAA under test. The testing described here provides an initial assessment of the beam-switch phenomena by digitally acquiring time series of the RF communications channel, under CW excitation, during the period of time that the beam switch transient occurs. Effects are analyzed using time-frequency distributions and instantaneous frequency estimation techniques. The results of tests conducted with CW excitation supports further Bit-Error-Rate (BER) testing of the PAA communication channel.

Anomalous Thrust Production from an RF Test Device Measured on a Low-Thrust Torsion Pendulum

NASA Technical Reports Server (NTRS)

Brady, David A.; White, Harold G.; March, Paul; Lawrence, James T.; Davies, Frank J.

2014-01-01

This paper describes the test campaigns designed to investigate and demonstrate viability of using classical magnetoplasmadynamics to obtain a propulsive momentum transfer via the quantum vacuum virtual plasma. This paper will not address the physics of the quantum vacuum plasma thruster (QVPT), but instead will describe the recent test campaign. In addition, it contains a brief description of the supporting radio frequency (RF) field analysis, lessons learned, and potential applications of the technology to space exploration missions. During the first (Cannae) portion of the campaign, approximately 40 micronewtons of thrust were observed in an RF resonant cavity test article excited at approximately 935 megahertz and 28 watts. During the subsequent (tapered cavity) portion of the campaign, approximately 91 micronewtons of thrust were observed in an RF resonant cavity test article excited at approximately 1933 megahertz and 17 watts. Testing was performed on a low-thrust torsion pendulum that is capable of detecting force at a single-digit micronewton level. Test campaign results indicate that the RF resonant cavity thruster design, which is unique as an electric propulsion device, is producing a force that is not attributable to any classical electromagnetic phenomenon and therefore is potentially demonstrating an interaction with the quantum vacuum virtual plasma.

Liquid Methane Conditioning Capabilities Developed at the NASA Glenn Research Center's Small Multi- Purpose Research Facility (SMiRF) for Accelerated Lunar Surface Storage Thermal Testing

NASA Technical Reports Server (NTRS)

Bamberger, Helmut H.; Robinson, R. Craig; Jurns, John M.; Grasl, Steven J.

2011-01-01

Glenn Research Center s Creek Road Cryogenic Complex, Small Multi-Purpose Research Facility (SMiRF) recently completed validation / checkout testing of a new liquid methane delivery system and liquid methane (LCH4) conditioning system. Facility checkout validation was conducted in preparation for a series of passive thermal control technology tests planned at SMiRF in FY10 using a flight-like propellant tank at simulated thermal environments from 140 to 350K. These tests will validate models and provide high quality data to support consideration of LCH4/LO2 propellant combination option for a lunar or planetary ascent stage.An infrastructure has been put in place which will support testing of large amounts of liquid methane at SMiRF. Extensive modifications were made to the test facility s existing liquid hydrogen system for compatibility with liquid methane. Also, a new liquid methane fluid conditioning system will enable liquid methane to be quickly densified (sub-cooled below normal boiling point) and to be quickly reheated to saturation conditions between 92 and 140 K. Fluid temperatures can be quickly adjusted to compress the overall test duration. A detailed trade study was conducted to determine an appropriate technique to liquid conditioning with regard to the SMiRF facility s existing infrastructure. In addition, a completely new roadable dewar has been procured for transportation and temporary storage of liquid methane. A new spherical, flight-representative tank has also been fabricated for integration into the vacuum chamber at SMiRF. The addition of this system to SMiRF marks the first time a large-scale liquid methane propellant test capability has been realized at Glenn.This work supports the Cryogenic Fluid Management Project being conducted under the auspices of the Exploration Technology Development Program, providing focused cryogenic fluid management technology efforts to support NASA s future robotic or human exploration missions.

Frontal sled tests comparing rear and forward facing child restraints with 1-3 year old dummies.

PubMed

Sherwood, C P; Crandall, J R

2007-01-01

Although most countries recommend transitioning children from rear facing (RF) to forward facing (FF) child restraints at one year of age, Swedish data suggests that RF restraints are more effective. The objective of this study was to compare RF and FF orientations in frontal sled tests. Four dummies (CRABI 12 mo, Q1.5, Hybrid III 3 yr, and Q3) were used to represent children from 1 to 3 years of age. Restraint systems tested included both 1) LATCH and 2) rigid ISOFIX with support leg designs. Rear facing restraints with support legs provided the best results for all injury measures, while RF restraints in general provided the lowest chest displacements and neck loads.

Factors Associated with HIV Testing Among Participants from Substance Use Disorder Treatment Programs in the US: A Machine Learning Approach.

PubMed

Pan, Yue; Liu, Hongmei; Metsch, Lisa R; Feaster, Daniel J

2017-02-01

HIV testing is the foundation for consolidated HIV treatment and prevention. In this study, we aim to discover the most relevant variables for predicting HIV testing uptake among substance users in substance use disorder treatment programs by applying random forest (RF), a robust multivariate statistical learning method. We also provide a descriptive introduction to this method for those who are unfamiliar with it. We used data from the National Institute on Drug Abuse Clinical Trials Network HIV testing and counseling study (CTN-0032). A total of 1281 HIV-negative or status unknown participants from 12 US community-based substance use disorder treatment programs were included and were randomized into three HIV testing and counseling treatment groups. The a priori primary outcome was self-reported receipt of HIV test results. Classification accuracy of RF was compared to logistic regression, a standard statistical approach for binary outcomes. Variable importance measures for the RF model were used to select the most relevant variables. RF based models produced much higher classification accuracy than those based on logistic regression. Treatment group is the most important predictor among all covariates, with a variable importance index of 12.9%. RF variable importance revealed that several types of condomless sex behaviors, condom use self-efficacy and attitudes towards condom use, and level of depression are the most important predictors of receipt of HIV testing results. There is a non-linear negative relationship between count of condomless sex acts and the receipt of HIV testing. In conclusion, RF seems promising in discovering important factors related to HIV testing uptake among large numbers of predictors and should be encouraged in future HIV prevention and treatment research and intervention program evaluations.

rf breakdown tests of mm-wave metallic accelerating structures

DOE PAGES

Dal Forno, Massimo; Dolgashev, Valery; Bowden, Gordon; ...

2016-01-06

In this study, we explore the physics and frequency-scaling of vacuum rf breakdowns at sub-THz frequencies. We present the experimental results of rf tests performed in metallic mm-wave accelerating structures. These experiments were carried out at the facility for advanced accelerator experimental tests (FACET) at the SLAC National Accelerator Laboratory. The rf fields were excited by the FACET ultrarelativistic electron beam. We compared the performances of metal structures made with copper and stainless steel. The rf frequency of the fundamental accelerating mode, propagating in the structures at the speed of light, varies from 115 to 140 GHz. The traveling wavemore » structures are 0.1 m long and composed of 125 coupled cavities each. We determined the peak electric field and pulse length where the structures were not damaged by rf breakdowns. We calculated the electric and magnetic field correlated with the rf breakdowns using the FACET bunch parameters. The wakefields were calculated by a frequency domain method using periodic eigensolutions. Such a method takes into account wall losses and is applicable to a large variety of geometries. The maximum achieved accelerating gradient is 0.3 GV/m with a peak surface electric field of 1.5 GV/m and a pulse length of about 2.4 ns.« less

Independent validation of the MMPI-2-RF Somatic/Cognitive and Validity scales in TBI Litigants tested for effort.

PubMed

Youngjohn, James R; Wershba, Rebecca; Stevenson, Matthew; Sturgeon, John; Thomas, Michael L

2011-04-01

The MMPI-2 Restructured Form (MMPI-2-RF; Ben-Porath & Tellegen, 2008) is replacing the MMPI-2 as the most widely used personality test in neuropsychological assessment, but additional validation studies are needed. Our study examines MMPI-2-RF Validity scales and the newly created Somatic/Cognitive scales in a recently reported sample of 82 traumatic brain injury (TBI) litigants who either passed or failed effort tests (Thomas & Youngjohn, 2009). The restructured Validity scales FBS-r (restructured symptom validity), F-r (restructured infrequent responses), and the newly created Fs (infrequent somatic responses) were not significant predictors of TBI severity. FBS-r was significantly related to passing or failing effort tests, and Fs and F-r showed non-significant trends in the same direction. Elevations on the Somatic/Cognitive scales profile (MLS-malaise, GIC-gastrointestinal complaints, HPC-head pain complaints, NUC-neurological complaints, and COG-cognitive complaints) were significant predictors of effort test failure. Additionally, HPC had the anticipated paradoxical inverse relationship with head injury severity. The Somatic/Cognitive scales as a group were better predictors of effort test failure than the RF Validity scales, which was an unexpected finding. MLS arose as the single best predictor of effort test failure of all RF Validity and Somatic/Cognitive scales. Item overlap analysis revealed that all MLS items are included in the original MMPI-2 Hy scale, making MLS essentially a subscale of Hy. This study validates the MMPI-2-RF as an effective tool for use in neuropsychological assessment of TBI litigants.

Fibrinogen, Riboflavin, and UVA to Immobilize a Corneal Flap – Molecular Mechanisms

PubMed Central

Littlechild, Stacy L.; Zhang, Yuntao; Tomich, John M.; Conrad, Gary W.

2012-01-01

Purpose. Tissue glue containing fibrinogen (FIB) and riboflavin (RF), upon exposure to long wavelength ultraviolet light (UVA, 365 nM) has been proposed potentially to solve long-standing problems presented by corneal wound and epithelial ingrowth side-effects from laser-assisted in situ keratomileuis (LASIK). Data presented in a previous study demonstrated an ability of FIB + RF + UVA to adhere two stromal surfaces; however, to our knowledge no molecular mechanisms have been proposed to account for interactions occurring between corneal extracellular matrix (ECM) and tissue glue molecules. Here, we document several covalent and noncovalent interactions between these classes of macromolecules. Methods. SDS-PAGE and Western blot techniques were used to identify covalent interactions between tissue glue molecules and corneal ECM molecules in either the presence or absence of RF and UVA, in vitro and ex vivo. Surface plasmon resonance (SPR) was used to characterize noncovalent interactions, and obtain ka, kd, and KD binding affinity values. Results. SDS-PAGE and Western blot analyses indicated that covalent interactions occurred between neighboring FIB molecules, as well as between FIB and collagen type I (Coll-I) proteins (in vitro and ex vivo). These interactions occurred only in the presence of RF and UVA. SPR data demonstrated the ability of FIB to bind noncovalently to corneal stroma molecules, Coll-I, decorin, dermatan sulfate, and corneal basement membrane molecules, laminin and heparan sulfate – only in the presence of Zn2+. Conclusions. Covalent and (zinc-mediated) noncovalent mechanisms involving FIB and stromal ECM molecules contribute to the adhesion created by FIB + RF + UVA. PMID:22879413

Langmuir probes for SPIDER (source for the production of ions of deuterium extracted from radio frequency plasma) experiment: Tests in BATMAN (Bavarian test machine for negative ions)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brombin, M., E-mail: matteo.brombin@igi.cnr.it; Spolaore, M.; Serianni, G.

2014-11-15

A prototype system of the Langmuir probes for SPIDER (Source for the production of Ions of Deuterium Extracted from RF plasma) was manufactured and experimentally qualified. The diagnostic was operated in RF (Radio Frequency) plasmas with cesium evaporation on the BATMAN (BAvarian Test MAchine for Negative ions) test facility, which can provide plasma conditions as expected in the SPIDER source. A RF passive compensation circuit was realised to operate the Langmuir probes in RF plasmas. The sensors’ holder, designed to better simulate the bias plate conditions in SPIDER, was exposed to a severe experimental campaign in BATMAN with cesium evaporation.more » No detrimental effect on the diagnostic due to cesium evaporation was found during the exposure to the BATMAN plasma and in particular the insulation of the electrodes was preserved. The paper presents the system prototype, the RF compensation circuit, the acquisition system (as foreseen in SPIDER), and the results obtained during the experimental campaigns.« less

Development of a dual-pulse RF driver for an S-band (= 2856 MHz) RF electron linear accelerator

NASA Astrophysics Data System (ADS)

Cha, Sungsu; Kim, Yujong; Lee, Byeong-No; Lee, Byung Cheol; Cha, Hyungki; Ha, Jang Ho; Park, Hyung Dal; Lee, Seung Hyun; Kim, Hui Su; Buaphad, Pikad

2016-04-01

The radiation equipment research division of Korea Atomic Energy Research Institute has developed a Container Inspection System (CIS) using a Radio Frequency (RF) electron linear accelerator for port security. The primary purpose of the CIS is to detect nuclear materials and explosives, as well country-specific prohibited substances, e.g., smuggled. The CIS consists of a 9/6 MeV dualenergy electron linear accelerator for distinguishing between organic and inorganic materials. The accelerator consists of an electron gun, an RF accelerating structure, an RF driver, a modulator, electromagnets, a cooling system, a X-ray generating target, X-ray collimator, a detector, and a container moving system. The RF driver is an important part of the configuration because it is the RF power source: it supplies the RF power to the accelerating structure. A unique aspect of the RF driver is that it generates dual RF power to generate dual energy (9/6 MeV). The advantage of this RF driver is that it can allow the pulse width to vary and can be used to obtain a wide range of energy output, and pulse repetition rates up to 300 Hz. For this reason, 140 W (5 MW - 9 MeV) and 37 W (3.4 MW - 6 MeV) power outputs are available independently. A high power test for 20 minutes demonstrate that stable dual output powers can be generated. Moreover, the dual power can be applied to the accelerator which has stable accelerator operation. In this paper, the design, fabrication and high power test of the RF driver for the RF electron linear accelerator (linac) are presented.

Identification of IRX1 as a Risk Locus for Rheumatoid Factor Positivity in Rheumatoid Arthritis in a Genome-Wide Association Study.

PubMed

Julià, Antonio; Blanco, Francisco; Fernández-Gutierrez, Benjamín; González, Antonio; Cañete, Juan D; Maymó, Joan; Alperi-López, Mercedes; Olivè, Alex; Corominas, Héctor; Martínez-Taboada, Víctor; González-Álvaro, Isidoro; Fernandez-Nebro, Antonio; Erra, Alba; Sánchez-Fernández, Simón; Alonso, Arnald; López-Lasanta, María; Tortosa, Raül; Codó, Laia; Lluis Gelpi, Josep; García-Montero, Andrés C; Bertranpetit, Jaume; Absher, Devin; Myers, Richard M; Tornero, Jesús; Marsal, Sara

2016-06-01

Rheumatoid factor (RF) is a well-established diagnostic and prognostic biomarker in rheumatoid arthritis (RA). However, ∼20% of RA patients are negative for this anti-IgG antibody. To date, only variation at the HLA-DRB1 gene has been associated with the presence of RF. This study was undertaken to identify additional genetic variants associated with RF positivity. A genome-wide association study (GWAS) for RF positivity was performed using an Illumina Quad610 genotyping platform. A total of 937 RF-positive and 323 RF-negative RA patients were genotyped for >550,000 single-nucleotide polymorphisms (SNPs). Association testing was performed using an allelic chi-square test implemented in Plink software. An independent cohort of 472 RF-positive and 190 RF-negative RA patients was used to validate the most significant findings. In the discovery stage, a SNP in the IRX1 locus on chromosome 5p15.3 (SNP rs1502644) showed a genome-wide significant association with RF positivity (P = 4.13 × 10(-8) , odds ratio [OR] 0.37 [95% confidence interval (95% CI) 0.26-0.53]). In the validation stage, the association of IRX1 with RF was replicated in an independent group of RA patients (P = 0.034, OR 0.58 [95% CI 0.35-0.97] and combined P = 1.14 × 10(-8) , OR 0.43 [95% CI 0.32-0.58]). To our knowledge, this is the first GWAS of RF positivity in RA. Variation at the IRX1 locus on chromosome 5p15.3 is associated with the presence of RF. Our findings indicate that IRX1 and HLA-DRB1 are the strongest genetic factors for RF production in RA. © 2016, American College of Rheumatology.

Reproduction of Meloidogyne chitwoodi on Popcorn Cultivars

PubMed Central

Cardwell, D. M.; Ingham, R. E.

1997-01-01

Popcorn cultivars were evaluated in field and greenhouse tests for resistance to the Columbia root-knot nematode, Meloidogyne chitwoodi, as potential resistant crops in potato rotations. A nematode reproductive factor (Rf) was calculated for each cultivar. Reproductive factor values also were compared on a relative basis as percentages of the Rf on a susceptible field corn standard, Pioneer 3578. Popcorn cultivars W206 and Robust 33-77 consistently supported low population densities of M. chitwoodi in repeated tests. However, WOC 9508 had the greatest resistance in any of the field tests, with an Rf value of 0.04. Cultivars with a mean field and greenhouse Rf value less than 50% of the value for Pioneer 3578 were WOC 9508 (8%), WOC 9554 (13%), W206 (15%), WOX 9512 (23%), Robust 33-77 (30%), Robust 20-70 (38%), WOC 9510 (41%), and WOC 9504 (42%). If these cultivars were used in rotation, M. chitwoodi population densities at the end of the popcorn season would be between 58% and 92% less than if Pioneer 3578 were grown. In greenhouse tests, WOX 9511, WOX 9528, WOC 9556, and WOX 9531 also had low Rf values (7-46% that of Pioneer 3578), but field testing of these cultivars is needed. PMID:19274265

New Combinational Method for Noninvasive Treatments of Superficial Tissues for Body Aesthetics Applications

NASA Astrophysics Data System (ADS)

Rybyanets, A. N.; Naumenko, A. A.

The paper introduces an innovative combinational treatment method based on ultrasonic standing waves (USW) technology for noninvasive surgical, therapeutic, lypolitic or cosmetic treatment of tissues including subcutaneous adipose tissue, cellulite or skin on arbitrary body part of patient. The method is based on simultaneous or successive applying of constructively interfering physically and biologically sensed influences: USW, ultrasonic shear waves, radio-frequency (RF) heating, and vacuum massage. The paper provides basic physical principles of USW as well as critical comparison of USW and HIFU methods. The results of finite-elements and finite- difference modeling of USW transducer design and nodal pattern structure in tissue are presented. Biological effects of USW-tissue interaction and synergetic aspects of USW and RF combination are explored. Combinational treatment transducer designs and original in-vitro experiments on tissues are described.

Development of a model and test equipment for cold flow tests at 500 atm of small nuclear light bulb configurations

NASA Technical Reports Server (NTRS)

Jaminet, J. F.

1972-01-01

A model and test equipment were developed and cold-flow-tested at greater than 500 atm in preparation for future high-pressure rf plasma experiments and in-reactor tests with small nuclear light bulb configurations. With minor exceptions, the model chamber is similar in design and dimensions to a proposed in-reactor geometry for tests with fissioning uranium plasmas in the nuclear furnace. The model and the equipment were designed for use with the UARL 1.2-MW rf induction heater in tests with rf plasmas at pressures up to 500 atm. A series of cold-flow tests of the model was then conducted at pressures up to about 510 atm. At 504 atm, the flow rates of argon and cooling water were 3.35 liter/sec (STP) and 26 gal/min, respectively. It was demonstrated that the model is capable of being operated for extended periods at the 500-atm pressure level and is, therefore, ready for use in initial high-pressure rf plasma experiments.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, Rolland

Many present and future particle accelerators are limited by the maximum electric gradient and peak surface fields that can be realized in RF cavities. Despite considerable effort, a comprehensive theory of RF breakdown has not been achieved and mitigation techniques to improve practical maximum accelerating gradients have had only limited success. Part of the problem is that RF breakdown in an evacuated cavity involves a complex mixture of effects, which include the geometry, metallurgy, and surface preparation of the accelerating structures and the make-up and pressure of the residual gas in which plasmas form. Studies showed that high gradients canmore » be achieved quickly in 805 MHz RF cavities pressurized with dense hydrogen gas, as needed for muon cooling channels, without the need for long conditioning times, even in the presence of strong external magnetic fields. This positive result was expected because the dense gas can practically eliminate dark currents and multipacting. In this project we used this high pressure technique to suppress effects of residual vacuum and geometry that are found in evacuated cavities in order to isolate and study the role of the metallic surfaces in RF cavity breakdown as a function of magnetic field, frequency, and surface preparation. One of the interesting and useful outcomes of this project was the unanticipated collaborations with LANL and Fermilab that led to new insights as to the operation of evacuated normal-conducting RF cavities in high external magnetic fields. Other accomplishments included: (1) RF breakdown experiments to test the effects of SF6 dopant in H2 and He gases with Sn, Al, and Cu electrodes were carried out in an 805 MHz cavity and compared to calculations and computer simulations. The heavy corrosion caused by the SF6 components led to the suggestion that a small admixture of oxygen, instead of SF6, to the hydrogen would allow the same advantages without the corrosion in a practical muon beam line. (2) A 1.3 GHz RF test cell capable of operating both at high pressure and in vacuum with replaceable electrodes was designed, built, and power tested in preparation for testing the frequency and geometry effects of RF breakdown at Argonne National Lab. At the time of this report this cavity is still waiting for the 1.3 GHz klystron to be available at the Wakefield Test Facility. (3) Under a contract with Los Alamos National Lab, an 805 MHz RF test cavity, known as the All-Seasons Cavity (ASC), was designed and built by Muons, Inc. to operate either at high pressure or under vacuum. The LANL project to use the (ASC) was cancelled and the testing of the cavity has been continued under the grant reported on here using the Fermilab Mucool Test Area (MTA). The ASC is a true pillbox cavity that has performed under vacuum in high external magnetic field better than any other and has demonstrated that the high required accelerating gradients for many muon cooling beam line designs are possible. (4) Under ongoing support from the Muon Acceleration Program, microscopic surface analysis and computer simulations have been used to develop models of RF breakdown that apply to both pressurized and vacuum cavities. The understanding of RF breakdown will lead to better designs of RF cavities for many applications. An increase in the operating accelerating gradient, improved reliability and shorter conditioning times can generate very significant cost savings in many accelerator projects.« less

Design and manufacture of the RF power supply and RF transmission line for SANAEM project Prometheus

NASA Astrophysics Data System (ADS)

Turemen, G.; Ogur, S.; Ahiska, F.; Yasatekin, B.; Cicek, E.; Ozbey, A.; Kilic, I.; Unel, G.; Alacakir, A.

2017-08-01

A 1-5 MeV proton beamline is being built by the Turkish Atomic Energy Authority in collaboration with a number of graduate students from different universities. The primary goal of the project, is to acquire the design ability and manufacturing capability of all the components locally. SPP will be an accelerator and beam diagnostics test facility and it will also serve the detector development community with its low beam current. This paper discusses the design and construction of the RF power supply and the RF transmission line components such as its waveguide converters and its circulator. Additionally low and high power RF test results are presented to compare the performances of the locally produced components to the commercially available ones.

Spacecraft-level verification of the Van Allen Probes' RF communication system

NASA Astrophysics Data System (ADS)

Crowne, M. J.; Srinivasan, D.; Royster, D.; Weaver, G.; Matlin, D.; Mosavi, N.

This paper presents the verification process, lessons learned, and selected test results of the radio frequency (RF) communication system of the Van Allen Probes, formerly known as the Radiation Belt Storm Probes (RBSP). The Van Allen Probes mission is investigating the doughnut-shaped regions of space known as the Van Allen radiation belts where the Sun interacts with charged particles trapped in Earth's magnetic field. Understanding this dynamic area that surrounds our planet is important to improving our ability to design spacecraft and missions for reliability and astronaut safety. The Van Allen Probes mission features two nearly identical spacecraft designed, built, and operated by the Johns Hopkins University Applied Physics Laboratory (JHU/APL) for the National Aeronautics and Space Administration (NASA). The RF communication system features the JHU/APL Frontier Radio. The Frontier Radio is a software-defined radio (SDR) designed for spaceborne communications, navigation, radio science, and sensor applications. This mission marks the first spaceflight usage of the Frontier Radio. RF ground support equipment (RF GSE) was developed using a ground station receiver similar to what will be used in flight and whose capabilities provided clarity into RF system performance that was previously not obtained until compatibility testing with the ground segments. The Van Allen Probes underwent EMC, acoustic, vibration, and thermal vacuum testing at the environmental test facilities at APL. During this time the RF communication system was rigorously tested to ensure optimal performance, including system-level testing down to threshold power levels. Compatibility tests were performed with the JHU/APL Satellite Communication Facility (SCF), the Universal Space Network (USN), and the Tracking and Data Relay Satellite System (TDRSS). Successful completion of this program as described in this paper validated the design of the system and demonstrated that it will be able to me- t all of the Van Allen Probes's communications requirements with its intended ground segments.

RF Conditioning and Testing of Fundamental Power Couplers for SNS Superconducting Cavity Production

DOE Office of Scientific and Technical Information (OSTI.GOV)

M. Stirbet; G.K. Davis; M. A. Drury

The Spallation Neutron Source (SNS) makes use of 33 medium beta (0.61) and 48 high beta (0.81) superconducting cavities. Each cavity is equipped with a fundamental power coupler, which should withstand the full klystron power of 550 kW in full reflection for the duration of an RF pulse of 1.3 msec at 60 Hz repetition rate. Before assembly to a superconducting cavity, the vacuum components of the coupler are submitted to acceptance procedures consisting of preliminary quality assessments, cleaning and clean room assembly, vacuum leak checks and baking under vacuum, followed by conditioning and RF high power testing. Similar acceptancemore » procedures (except clean room assembly and baking) were applied for the airside components of the coupler. All 81 fundamental power couplers for SNS superconducting cavity production have been RF power tested at JLAB Newport News and, beginning in April 2004 at SNS Oak Ridge. This paper gives details of coupler processing and RF high power-assessed performances.« less

High-powered microwave ablation with a small-gauge, gas-cooled antenna: initial ex vivo and in vivo results.

PubMed

Lubner, Meghan G; Hinshaw, J Louis; Andreano, Anita; Sampson, Lisa; Lee, Fred T; Brace, Christopher L

2012-03-01

To evaluate the performance of a gas-cooled, high-powered microwave system. Investigators performed 54 ablations in ex vivo bovine livers using three devices-a single 17-gauge cooled radiofrequency(RF) electrode; a cluster RF electrode; and a single 17-gauge, gas-cooled microwave (MW) antenna-at three time points (n = 6 at 4 minutes, 12 minutes, and 16 minutes). RF power was applied using impedance-based pulsing with maximum 200 W generator output. MW power of 135 W at 2.45 GHz was delivered continuously. An approved in vivo study was performed using 13 domestic pigs. Hepatic ablations were performed using single applicators and the above-mentioned MW and RF generator systems at treatment times of 2 minutes (n = 7 MW, n = 6 RF), 5 minutes (n = 23 MW, n = 8 RF), 7 minutes (n = 11 MW, n = 6 RF), and 10 minutes (n = 7 MW, n = 9 RF). Mean transverse diameter and length of the ablation zones were compared using analysis of variance (ANOVA) with post-hoc t tests and Wilcoxon rank-sum tests. Single ex vivo MW ablations were larger than single RF ablations at all time points (MW mean diameter range 3.5-4.8 cm 4-16 minutes; RF mean diameter range 2.6-3.1 cm 4-16 minutes) (P < .05). There was no difference in mean diameter between cluster RF and MW ablations (RF 3.3-4.4 cm 4-16 minutes; P = .4-.9). In vivo lesion diameters for MW (and RF) were as follows: 2.6 cm ± 0.72 (RF 1.5 cm ± 0.14), 3.6 cm ± 0.89 (RF 2.0 cm ± 0.4), 3.4 cm ± 0.87 (RF 1.8 cm ± 0.23), and 3.8 cm ± 0.74 (RF 2.1 cm ± 0.3) at 2 minutes, 5 minutes, 7 minutes, and 10 minutes (P < .05 all time points). Gas-cooled, high-powered MW ablation allows the generation of large ablation zones in short times. Copyright © 2012 SIR. Published by Elsevier Inc. All rights reserved.

Gas Generation Testing of Spherical Resorcinol-Formaldehyde (sRF) Resin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Colburn, Heather A.; Bryan, Samuel A.; Camaioni, Donald M.

This report describes gas generation testing of the spherical resorcinol-formaldehyde (sRF) resin that was conducted to support the technology maturation of the LAWPS facility. The current safety basis for the LAWPS facility is based primarily on two studies that had limited or inconclusive data sets. The two studies indicated a 40% increase in hydrogen generation rate of water (as predicted by the Hu model) with sRF resin over water alone. However, the previous studies did not test the range of conditions (process fluids and temperatures) that are expected in the LAWPS facility. Additionally, the previous studies did not obtain replicatemore » test results or comparable liquid-only control samples. All of the testing described in this report, conducted with water, 0.45M nitric acid, and waste simulants with and without sRF resin, returned hydrogen generation rates that are within the current safety basis for the facility of 1.4 times the Hu model output for water.« less

[Rheumatoid factor activity as a disturbing factor in the serological diagnosis of specific IgM antibodies].

PubMed

Lindenschmidt, E G

1984-04-01

Rheumatoid factors (RF) are autoantibodies mainly directed against autologous IgG. They belong at most to the IgM class antibodies. It is demonstrated at groups with unsolved hepatitis B, rubella, syphilis and toxoplasmose infection that RF do occur not rarely at these patients even without rheumatoid arthritis. This is probably due to stimulation by antigen-IgG-complexes. During serologic detection of specific IgM antibodies they present an antigen independent mu-specificity. So the test for specific IgM might even loose its diagnostic and possibly therapy indicating value. It is shown how the disturbance by RF can be calculated after adsorption with aggregated IgG. Also RF can be titrated by an enzyme immunoassay (ELISA). With IgG coated latex particles RF can be eliminated prior to the IgM-test. Solid phase techniques which are applied with enzyme-coupled antigen instead of marked anti-IgM cannot be disturbed by RF significantly.

Small Multi-Purpose Research Facility (SMiRF)

NASA Image and Video Library

2015-10-15

NASA Glenn engineer Monica Guzik in the Small Multi-Purpose Research Facility (SMiRF). The facility provides the ability to simulate the environmental conditions encountered in space for a variety of cryogenic applications such as thermal protection systems, fluid transfer operations and propellant level gauging. SMiRF is a low-cost, small-scale screening facility for concept and component testing of a wide variety of hardware and is capable of testing cryogenic hydrogen, oxygen, methane and nitrogen.

Electromagnetic radiation and behavioural response of ticks: an experimental test.

PubMed

Vargová, Blažena; Majláth, Igor; Kurimský, Juraj; Cimbala, Roman; Kosterec, Michal; Tryjanowski, Piotr; Jankowiak, Łukasz; Raši, Tomáš; Majláthová, Viktória

2018-05-01

Factors associated with the increased usage of electronic devices, wireless technologies and mobile phones nowadays are present in increasing amounts in our environment. All living organisms are constantly affected by electromagnetic radiation which causes serious environmental pollution. The distribution and density of ticks in natural habitats is influenced by a complex of abiotic and biotic factors. Exposure to radio-frequency electromagnetic field (RF-EMF) constitutes a potential cause altering the presence and distribution of ticks in the environment. Our main objective was to determine the affinity of Dermacentor reticulatus ticks towards RF-EMF exposure. Originally designed and constructed radiation-shielded tube (RST) test was used to test the affinity of ticks under controlled laboratory conditions. All test were performed in an electromagnetic compatibility laboratory in an anechoic chamber. Ticks were irradiated using a Double-Ridged Waveguide Horn Antenna to RF-EMF at 900 and 5000 MHz, 0 MHz was used as control. The RF-EMF exposure to 900 MHz induced a higher concentration of ticks on irradiated arm of RST as opposed to the RF-EMF at 5000 MHz, which caused an escape of ticks to the shielded arm. This study represents the first experimental evidence of RF-EMF preference in D. reticulatus. The projection of obtained results to the natural environment could help assess the risk of tick borne diseases and could be a tool of preventive medicine.

An RF-induced voltage sensor for investigating pacemaker safety in MRI.

PubMed

Barbier, Thérèse; Piumatti, Roberto; Hecker, Bertrand; Odille, Freddy; Felblinger, Jacques; Pasquier, Cédric

2014-12-01

Magnetic resonance imaging (MRI) is inadvisable for patients with pacemakers, as radiofrequency (RF) voltages induced in the pacemaker leads may cause the device to malfunction. Our goal is to develop a sensor to measure such RF-induced voltages during MRI safety tests. A sensor was designed (16.6 cm(2)) for measuring voltages at the connection between the pacemaker lead and its case. The induced voltage is demodulated, digitized, and transferred by optical fibres. The sensor was calibrated on the bench using RF pulses of known amplitude and duration. Then the sensor was tested during MRI scanning at 1.5 T in a saline gel filled phantom. Bench tests showed measurement errors below 5% with a (-40 V; +40 V) range, a precision of 0.06 V, and a temporal resolution of 24.2 μs. In MRI tests, variability in the measured voltages was below 3.7% for 996 measurements with different sensors and RF exposure. Coupling between the sensor and the MRI electromagnetic environment was estimated with a second sensor connected and was below 6.2%. For a typical clinical MRI sequence, voltages around ten Vp were detected. We have built an accurate and reproducible tool for measuring RF-induced voltages in pacemaker leads during MR safety investigations. The sensor might also be used with other conducting cables including those used for electrocardiography and neurostimulation.

Cable Modems' Transmitted RF: A Study of SNR, Error Rates, Transmit Levels, and Trouble Call Metrics

ERIC Educational Resources Information Center

Tebbetts, Jo A.

2013-01-01

Hypotheses were developed and tested to measure the cable modems operational metrics response to a reconfiguration of the cable modems' transmitted RF applied to the CMTS. The purpose of this experiment was to compare two groups on the use of non-federal RF spectrum to determine if configuring the cable modems' transmitted RF from 25.2…

Possible cause for altered spatial cognition of prepubescent rats exposed to chronic radiofrequency electromagnetic radiation.

PubMed

Narayanan, Sareesh Naduvil; Kumar, Raju Suresh; Karun, Kalesh M; Nayak, Satheesha B; Bhat, P Gopalakrishna

2015-10-01

The effects of chronic and repeated radiofrequency electromagnetic radiation (RFEMR) exposure on spatial cognition and hippocampal architecture were investigated in prepubescent rats. Four weeks old male Wistar rats were exposed to RF-EMR (900 MHz; SAR-1.15 W/kg with peak power density of 146.60 μW/cm(2)) for 1 h/day, for 28 days. Followed by this, spatial cognition was evaluated by Morris water maze test. To evaluate the hippocampal morphology; H&E staining, cresyl violet staining, and Golgi-Cox staining were performed on hippocampal sections. CA3 pyramidal neuron morphology and surviving neuron count (in CA3 region) were studied using H&E and cresyl violet stained sections. Dendritic arborization pattern of CA3 pyramidal neuron was investigated by concentric circle method. Progressive learning abilities were found to be decreased in RF-EMR exposed rats. Memory retention test performed 24 h after the last training revealed minor spatial memory deficit in RF-EMR exposed group. However, RF-EMR exposed rats exhibited poor spatial memory retention when tested 48 h after the final trial. Hirano bodies and Granulovacuolar bodies were absent in the CA3 pyramidal neurons of different groups studied. Nevertheless, RF-EMR exposure affected the viable cell count in dorsal hippocampal CA3 region. RF-EMR exposure influenced dendritic arborization pattern of both apical and basal dendritic trees in RF-EMR exposed rats. Structural changes found in the hippocampus of RF-EMR exposed rats could be one of the possible reasons for altered cognition.

Linear electromagnetic excitation of an asymmetric low pressure capacitive discharge with unequal sheath widths

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lieberman, M. A., E-mail: lieber@eecs.berkeley.edu; Lichtenberg, A. J.; Kawamura, E.

It is well-known that standing waves having radially center-high radio frequency (rf) voltage profiles exist in high frequency capacitive discharges. In this work, we determine the symmetric and antisymmetric radially propagating waves in a cylindrical capacitive discharge that is asymmetrically driven at the lower electrode by an rf voltage source. The discharge is modeled as a uniform bulk plasma which at lower frequencies has a thicker sheath at the smaller area powered electrode and a thinner sheath at the larger area grounded electrode. These are self-consistently determined at a specified density using the Child law to calculate sheath widths andmore » the electron power balance to calculate the rf voltage. The fields and the system resonant frequencies are determined. The center-to-edge voltage ratio on the powered electrode is calculated versus frequency, and central highs are found near the resonances. The results are compared with simulations in a similar geometry using a two-dimensional hybrid fluid-analytical code, giving mainly a reasonable agreement. The analytic model may be useful for finding good operating frequencies for a given discharge geometry and power.« less

Core Temperature and Surface Heat Flux During Exercise in Heat While Wearing Body Armor

DTIC Science & Technology

2015-10-26

Table 7, overall dry > humid, there were no significant differences for energy costs (M) between environments. When compared to the estimated M...KB, Givoni B, & Goldman RF. Predicting energy expenditure with loads while standing or walking very slowly. J Appl Physiol 43(4): 577-581, 1977...No. 0704-0188 The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for

R & D of a Gas-Filled RF Beam Profile Monitor for Intense Neutrino Beam Experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yonehara, K.; Backfish, M.; Moretti, A.

We report the R&D of a novel radiation-robust hadron beam profile monitor based on a gas-filled RF cavity for intense neutrino beam experiments. An equivalent RF circuit model was made and simulated to optimize the RF parameter in a wide beam intensity range. As a result, the maximum acceptable beam intensity in the monitor is significantly increased by using a low-quality factor RF cavity. The plan for the demonstration test is set up to prepare for future neutrino beam experiments.

Looking northeast from Test Stand 'A' superstructure towards Test Stand ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Looking northeast from Test Stand 'A' superstructure towards Test Stand 'D' tower (4223/E-24, left background), Test Stand 'C' tower (4217/E-18, center), and Test Stand 'B' (4215/E-16, right foreground). - Jet Propulsion Laboratory Edwards Facility, Edwards Air Force Base, Boron, Kern County, CA

Complete multipactor suppression in an X-band dielectric-loaded accelerating structure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jing, C.; Gold, S. H.; Fischer, Richard

2016-05-09

Multipactor is a major issue limiting the gradient of rf-driven Dielectric-Loaded Accelerating (DLA) structures. Theoretical models have predicted that an axial magnetic field applied to DLA structures may completely block the multipactor discharge. However, previous attempts to demonstrate this magnetic field effect in an X-band traveling-wave DLA structure were inconclusive, due to the axial variation of the applied magnetic field, and showed only partial suppression of the multipactor loading [Jing et al., Appl. Phys. Lett. 103, 213503 (2013)]. The present experiment has been performed under improved conditions with a uniform axial magnetic field extending along the length of an X-bandmore » standing-wave DLA structure. Multipactor loading began to be continuously reduced starting from 3.5 kG applied magnetic field and was completely suppressed at 8 kG. Dependence of multipactor suppression on the rf gradient inside the DLA structure was also measured.« less

Teaching parents about responsive feeding through a vicarious learning video: A pilot randomized controlled trial

USDA-ARS?s Scientific Manuscript database

The American Academy of Pediatrics and World Health Organization recommend responsive feeding (RF) to promote healthy eating behaviors in early childhood. This project developed and tested a vicarious learning video to teach parents RF practices. A RF vicarious learning video was developed using com...

The NASA B-757 HIRF Test Series: Flight Test Results

NASA Technical Reports Server (NTRS)

Moeller, Karl J.; Dudley, Kenneth L.

1997-01-01

In 1995, the NASA Langley Research Center conducted a series of aircraft tests aimed at characterizing the electromagnetic environment (EME) in and around a Boeing 757 airliner. Measurements were made of the electromagnetic energy coupled into the aircraft and the signals induced on select structures as the aircraft was flown past known RF transmitters. These measurements were conducted to provide data for the validation of computational techniques for the assessment of electromagnetic effects in commercial transport aircraft. This paper reports on the results of flight tests using RF radiators in the HF, VHF, and UHF ranges and on efforts to use computational and analytical techniques to predict RF field levels inside the airliner at these frequencies.

Status of RF beryllium characterization for ITER Fist Wall

NASA Astrophysics Data System (ADS)

Kupriyanov, I. B.; Nikolaev, G. N.; Roedig, M.; Gervash, A. А.; Linke, I. J.; Kurbatova, L. A.; Perevalov, S. I.; Giniyatulin, R. N.

2011-10-01

The status of RF R&D activities in production and characterization of TGP-56FW beryllium grade is presented. The results of metallographic studies of microstructure and cracks morphology are reported for full-scale Be tiles (56 × 56 × 10 mm) subjected to VDE simulation tests in TSEFEY-M testing facility (VDE-10 MJ/m 2 during 0.1 s, 1 shot ) and following low cycle thermal fatigue tests (500 thermal cycles at 1.5 MW/m 2). First results of plasma disruption tests ( E = 1.2-5 MJ/m 2, 5 ms), which were obtained during the realization of Thermal Shock/VDE Qualification program of RF beryllium in JUDITH-1 facility, are also discussed.

Analog Techniques in CEBAF's RF Control System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hovater, J.; Fugitt, Jock

1988-01-01

Recent developments in high-speed analog technology have progressed into the areas of traditional RF technology.Diode-related devices are being replaced by analog IC's in the CEBAF RF control system.Complex phase modulators and attenuators have been successfully tested at 70 MHz.They have three advantages over existing technology: lower cost, less temperature sensitivity, and more linearity.RF signal conditioning components and how to implement the new analog IC's will be covered in this paper.

Repetitively Pulsed High Power RF Solid-State System

NASA Astrophysics Data System (ADS)

Bowman, Chris; Ziemba, Timothy; Miller, Kenneth E.; Prager, James; Quinley, Morgan

2017-10-01

Eagle Harbor Technologies, Inc. (EHT) is developing a low-cost, fully solid-state architecture for the generation of the RF frequencies and power levels necessary for plasma heating and diagnostic systems at validation platform experiments within the fusion science community. In Year 1 of this program, EHT has developed a solid-state RF system that combines an inductive adder, nonlinear transmission line (NLTL), and antenna into a single system that can be deployed at fusion science experiments. EHT has designed and optimized a lumped-element NLTL that will be suitable RF generation near the lower-hybrid frequency at the High Beta Tokamak (HBT) located at Columbia University. In Year 2, EHT will test this system at the Helicity Injected Torus at the University of Washington and HBT at Columbia. EHT will present results from Year 1 testing and optimization of the NLTL-based RF system. With support of DOE SBIR.

The development of data acquisition and processing application system for RF ion source

NASA Astrophysics Data System (ADS)

Zhang, Xiaodan; Wang, Xiaoying; Hu, Chundong; Jiang, Caichao; Xie, Yahong; Zhao, Yuanzhe

2017-07-01

As the key ion source component of nuclear fusion auxiliary heating devices, the radio frequency (RF) ion source is developed and applied gradually to offer a source plasma with the advantages of ease of control and high reliability. In addition, it easily achieves long-pulse steady-state operation. During the process of the development and testing of the RF ion source, a lot of original experimental data will be generated. Therefore, it is necessary to develop a stable and reliable computer data acquisition and processing application system for realizing the functions of data acquisition, storage, access, and real-time monitoring. In this paper, the development of a data acquisition and processing application system for the RF ion source is presented. The hardware platform is based on the PXI system and the software is programmed on the LabVIEW development environment. The key technologies that are used for the implementation of this software programming mainly include the long-pulse data acquisition technology, multi-threading processing technology, transmission control communication protocol, and the Lempel-Ziv-Oberhumer data compression algorithm. Now, this design has been tested and applied on the RF ion source. The test results show that it can work reliably and steadily. With the help of this design, the stable plasma discharge data of the RF ion source are collected, stored, accessed, and monitored in real-time. It is shown that it has a very practical application significance for the RF experiments.

Analysis of emotionality and locomotion in radio-frequency electromagnetic radiation exposed rats.

PubMed

Narayanan, Sareesh Naduvil; Kumar, Raju Suresh; Paval, Jaijesh; Kedage, Vivekananda; Bhat, M Shankaranarayana; Nayak, Satheesha; Bhat, P Gopalakrishna

2013-07-01

In the current study the modulatory role of mobile phone radio-frequency electromagnetic radiation (RF-EMR) on emotionality and locomotion was evaluated in adolescent rats. Male albino Wistar rats (6-8 weeks old) were randomly assigned into the following groups having 12 animals in each group. Group I (Control): they remained in the home cage throughout the experimental period. Group II (Sham exposed): they were exposed to mobile phone in switch-off mode for 28 days, and Group III (RF-EMR exposed): they were exposed to RF-EMR (900 MHz) from an active GSM (Global system for mobile communications) mobile phone with a peak power density of 146.60 μW/cm(2) for 28 days. On 29th day, the animals were tested for emotionality and locomotion. Elevated plus maze (EPM) test revealed that, percentage of entries into the open arm, percentage of time spent on the open arm and distance travelled on the open arm were significantly reduced in the RF-EMR exposed rats. Rearing frequency and grooming frequency were also decreased in the RF-EMR exposed rats. Defecation boli count during the EPM test was more with the RF-EMR group. No statistically significant difference was found in total distance travelled, total arm entries, percentage of closed arm entries and parallelism index in the RF-EMR exposed rats compared to controls. Results indicate that mobile phone radiation could affect the emotionality of rats without affecting the general locomotion.

Visible spectra of (474640) 2004 VN112-2013 RF98 with OSIRIS at the 10.4 m GTC: evidence for binary dissociation near aphelion among the extreme trans-Neptunian objects

NASA Astrophysics Data System (ADS)

de León, J.; de la Fuente Marcos, C.; de la Fuente Marcos, R.

2017-05-01

The existence of significant anisotropies in the distributions of the directions of perihelia and orbital poles of the known extreme trans-Neptunian objects (ETNOs) has been used to claim that trans-Plutonian planets may exist. Among the known ETNOs, the pair (474640) 2004 VN112-2013 RF98 stands out. Their orbital poles and the directions of their perihelia and their velocities at perihelion/aphelion are separated by a few degrees, but orbital similarity does not necessarily imply common physical origin. In an attempt to unravel their physical nature, visible spectroscopy of both targets was obtained using the OSIRIS camera-spectrograph at the 10.4 m Gran Telescopio Canarias (GTC). From the spectral analysis, we find that 474640-2013 RF98 have similar spectral slopes (12 versus 15 per cent/0.1 μm), very different from Sedna's but compatible with those of (148209) 2000 CR105 and 2012 VP113. These five ETNOs belong to the group of seven linked to the Planet Nine hypothesis. A dynamical pathway consistent with these findings is dissociation of a binary asteroid during a close encounter with a planet and we confirm its plausibility using N-body simulations. We thus conclude that both the dynamical and spectroscopic properties of 474640-2013 RF98 favour a genetic link and their current orbits suggest that the pair was kicked by a perturber near aphelion.

Beam Test of a Dielectric Loaded High Pressure RF Cavity for Use in Muon Cooling Channels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Freemire, Ben; Bowring, Daniel; Kochemirovskiy, Alexey

2016-06-01

Bright muon sources require six dimensional cooling to achieve acceptable luminosities. Ionization cooling is the only known method able to do so within the muon lifetime. One proposed cooling channel, the Helical Cooling Channel, utilizes gas filled radio frequency cavities to both mitigate RF breakdown in the presence of strong, external magnetic fields, and provide the cooling medium. Engineering constraints on the diameter of the magnets within which these cavities operate dictate the radius of the cavities be decreased at their nominal operating frequency. To accomplish this, one may load the cavities with a larger dielectric material. A 99.5% aluminamore » ring was inserted in a high pressure RF test cell and subjected to an intense proton beam at the MuCool Test Area at Fermilab. The results of the performance of this dielectric loaded high pressure RF cavity will be presented.« less

Aerial shows Stennis test stands

NASA Image and Video Library

2004-04-16

An aerial photo shows the B-1/B-2 Test Stand (foreground), A-2 Test Stand (middle) and A-1 Test Stand (back). The historic stands have been used to test engines used on every manned Apollo and space shuttle mission.

9. WEST SIDE, TEST STAND AND SUPERSTRUCTURE. TEST STAND 1B ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

9. WEST SIDE, TEST STAND AND SUPERSTRUCTURE. TEST STAND 1-B IN DISTANCE. Looking east. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-A, Test Area 1-120, north end of Jupiter Boulevard, Boron, Kern County, CA

Tuner design and RF test of a four-rod RFQ

NASA Astrophysics Data System (ADS)

Zhou, QuanFeng; Zhu, Kun; Guo, ZhiYu; Kang, MingLei; Gao, ShuLi; Lu, YuanRong; Chen, JiaEr

2011-12-01

A mini-vane four-rod radio frequency quadruple (RFQ) accelerator has been built for neutron imaging. The RFQ will operate at 201.5 MHz, and its length is 2.7 m. The original electric field distribution along the electrodes is not flat. The resonant frequency needs to be tuned to the operating value. And the frequency needs to be compensated for temperature change during high power RF test and beam test. As tuning such a RFQ is difficult, plate tuners and stick tuners are designed. This paper will present the tuners design, the tuning procedure, and the RF properties of the RFQ.

Development of a 1-m plasma source for heavy ion beam charge neutralization

NASA Astrophysics Data System (ADS)

Efthimion, Philip C.; Gilson, Erik P.; Grisham, Larry; Davidson, Ronald C.; Yu, Simon; Waldron, William; Grant Logan, B.

2005-05-01

Highly ionized plasmas are being employed as a medium for charge neutralizing heavy ion beams in order to focus to a small spot size. Calculations suggest that plasma at a density of 1-100 times the ion beam density and at a length ˜0.1-1 m would be suitable for achieving a high level of charge neutralization. A radio frequency (RF) source was constructed at the Princeton Plasma Physics Laboratory (PPPL) in support of the joint Neutralized Transport Experiment (NTX) at the Lawrence Berkeley National Laboratory (LBNL) to study ion beam neutralization. Pulsing the source enabled operation at pressures ˜10 -6 Torr with plasma densities of 10 11 cm -3. Near 100% ionization was achieved. The plasma was 10 cm in length, but future experiments require a source 1 m long. The RF source does not easily scale to the length. Consequently, large-volume plasma sources based upon ferroelectric ceramics are being considered. These sources have the advantage of being able to increase the length of the plasma and operate at low neutral pressures. The source will utilize the ferroelectric ceramic BaTiO 3 to form metal plasma. A 1 m long section of the drift tube inner surface of NTX will be covered with ceramic. A high voltage (˜1-5 kV) is applied between the drift tube and the front surface of the ceramic by placing a wire grid on the front surface. Plasma densities of 10 12 cm -3 and neutral pressures ˜10 -6 Torr are expected. A test stand to produce 20 cm long plasma is being constructed and will be tested before a 1 m long source is developed.

Comparative Analysis of RF Emission Based Fingerprinting Techniques for ZigBee Device Classification

DTIC Science & Technology

quantify the differences invarious RF fingerprinting techniques via comparative analysis of MDA/ML classification results. The findings herein demonstrate...correct classification rates followed by COR-DNA and then RF-DNA in most test cases and especially in low Eb/N0 ranges, where ZigBee is designed to operate.

rf improvements for Spallation Neutron Source H- ion sourcea)

NASA Astrophysics Data System (ADS)

Kang, Y. W.; Fuja, R.; Goulding, R. H.; Hardek, T.; Lee, S.-W.; McCarthy, M. P.; Piller, M. C.; Shin, K.; Stockli, M. P.; Welton, R. F.

2010-02-01

The Spallation Neutron Source at Oak Ridge National Laboratory is ramping up the accelerated proton beam power to 1.4 MW and just reached 1 MW. The rf-driven multicusp ion source that originates from the Lawrence Berkeley National Laboratory has been delivering ˜38 mA H- beam in the linac at 60 Hz, 0.9 ms. To improve availability, a rf-driven external antenna multicusp ion source with a water-cooled ceramic aluminum nitride (AlN) plasma chamber is developed. Computer modeling and simulations have been made to analyze and optimize the rf performance of the new ion source. Operational statistics and test runs with up to 56 mA medium energy beam transport beam current identify the 2 MHz rf system as a limiting factor in the system availability and beam production. Plasma ignition system is under development by using a separate 13 MHz system. To improve the availability of the rf power system with easier maintenance, we tested a 70 kV isolation transformer for the 80 kW, 6% duty cycle 2 MHz amplifier to power the ion source from a grounded solid-state amplifier.

rf improvements for Spallation Neutron Source H- ion source.

PubMed

Kang, Y W; Fuja, R; Goulding, R H; Hardek, T; Lee, S-W; McCarthy, M P; Piller, M C; Shin, K; Stockli, M P; Welton, R F

2010-02-01

The Spallation Neutron Source at Oak Ridge National Laboratory is ramping up the accelerated proton beam power to 1.4 MW and just reached 1 MW. The rf-driven multicusp ion source that originates from the Lawrence Berkeley National Laboratory has been delivering approximately 38 mA H(-) beam in the linac at 60 Hz, 0.9 ms. To improve availability, a rf-driven external antenna multicusp ion source with a water-cooled ceramic aluminum nitride (AlN) plasma chamber is developed. Computer modeling and simulations have been made to analyze and optimize the rf performance of the new ion source. Operational statistics and test runs with up to 56 mA medium energy beam transport beam current identify the 2 MHz rf system as a limiting factor in the system availability and beam production. Plasma ignition system is under development by using a separate 13 MHz system. To improve the availability of the rf power system with easier maintenance, we tested a 70 kV isolation transformer for the 80 kW, 6% duty cycle 2 MHz amplifier to power the ion source from a grounded solid-state amplifier.

Demonstration of the High RF Power Production Feasibility in the CLIC Power Extraction and Transfer Structure (PETS)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cappelletti, A.; /CERN; Dolgashev, V.

A fundamental element of the CLIC concept is two-beam acceleration, where RF power is extracted from a high current, low energy drive beam in order to accelerate the low current main beam to high energy. The CLIC Power Extraction and Transfer Structure (PETS) is a passive microwave device in which bunches of the drive beam interact with the constant impedance of the periodically loaded waveguide and excite preferentially the synchronous mode. The RF power produced is collected downstream of the structure by means of the RF power extractor; it is delivered to the main linac using the waveguide network connectingmore » the PETS to the main CLIC accelerating structures. The PETS should produce 135 MW at 240 ns RF pulses at a very low breakdown rate: BDR < 10{sup -7}/pulse/m. Over 2010, a thorough high RF power testing program was conducted in order to investigate the ultimate performance and the limiting factors for the PETS operation. The testing program is described and the results are presented.« less

New method to monitor RF safety in MRI-guided interventions based on RF induced image artefacts.

PubMed

van den Bosch, Michiel R; Moerland, Marinus A; Lagendijk, Jan J W; Bartels, Lambertus W; van den Berg, Cornelis A T

2010-02-01

Serious tissue heating may occur at the tips of elongated metallic structures used in MRI-guided interventions, such as vascular guidewires, catheters, biopsy needles, and brachytherapy needles. This heating is due to resonating electromagnetic radiofrequency (RF) waves along the structure. Since it is hard to predict the exact length at which resonance occurs under in vivo conditions, there is a need for methods to monitor this resonance behavior. In this study, the authors propose a method based on the RF induced image artefacts and demonstrate its applicability in two phantom experiments. The authors developed an analytical model that describes the RF induced image artefacts as a function of the induced current in an elongated metallic structure placed parallel to the static magnetic field. It describes the total RF field as a sum of the RF fields produced by the transmit coil of the MR scanner and by the elongated metallic structure. Several spoiled gradient echo images with different nominal flip angle settings were acquired to map the B1+ field, which is a quantitative measure for the RF distortion around the structure. From this map, the current was extracted by fitting the analytical model. To investigate the sensitivity of our method we performed two phantom experiments with different setup parameters: One that mimics a brachytherapy needle insertion and one that resembles a guidewire intervention. In the first experiment, a short needle was placed centrally in the MR bore to ensure that the induced currents would be small. In the second experiment, a longer wire was placed in an off-center position to mimic a worst case scenario for the patient. In both experiments, a Luxtron (Santa Clara, CA) fiberoptic temperature sensor was positioned at the structure tip to record the temperature. In the first experiment, no significant temperature increases were measured, while the RF image artefacts and the induced currents in the needle increased with the applied insertion depth. The maximum induced current in the needle was 44 mA. Furthermore, a standing wave pattern became clearly visible for larger insertion depths. In the second experiment, significant temperature increases up to 2.4 degrees C in 1 min were recorded during the image acquisitions. The maximum current value was 1.4 A. In both experiments, a proper estimation of the current in the metallic structure could be made using our analytical model. The authors have developed a method to quantitatively determine the induced current in an elongated metallic structure from its RF distortion. This creates a powerful and sensitive method to investigate the resonant behavior of RF waves along elongated metallic structures used for MRI-guided interventions, for example, to monitor the RF safety or to inspect the influence of coating on the resonance length. Principally, it can be applied under in vivo conditions and for noncylindrical metallic structures such as hip implants by taking their geometry into account.

An assessment of false positive rates for malaria rapid diagnostic tests caused by non-Plasmodium infectious agents and immunological factors.

PubMed

Gatton, Michelle L; Ciketic, Sadmir; Barnwell, John W; Cheng, Qin; Chiodini, Peter L; Incardona, Sandra; Bell, David; Cunningham, Jane; González, Iveth J

2018-01-01

Malaria rapid diagnostic tests (RDTs) can produce false positive (FP) results in patients with human African trypanosomiasis and rheumatoid factor (RF), but specificity against other infectious agents and immunological factors is largely unknown. Low diagnostic specificity caused by cross-reactivity may lead to over-estimates of the number of malaria cases and over-use of antimalarial drugs, at the cost of not diagnosing and treating the true underlying condition. Data from the WHO Malaria RDT Product Testing Programme was analysed to assess FP rates of 221 RDTs against four infectious agents (Chagas, dengue, Leishmaniasis and Schistosomiasis) and four immunological factors (anti-nuclear antibody, human anti-mouse antibody (HAMA), RF and rapid plasma regain). Only RDTs with a FP rate against clean negative samples less than 10% were included. Paired t-tests were used to compare product-specific FP rates on clean negative samples and samples containing non-Plasmodium infectious agents and immunological factors. Forty (18%) RDTs showed no FP results against any tested infectious agent or immunological factor. In the remaining RDTs significant and clinically relevant increases in FP rates were observed for samples containing HAMA and RF (P<0.001). There were significant correlations between product-matched FP rates for RF and HAMA on all RDT test bands (P<0.001), and FP rates for each infectious agent and immunological factor were also correlated between test bands of combination RDTs (P≤0.002). False positive results against non-Plasmodium infectious agents and immunological factors does not appear to be a universal property of malaria RDTs. However, since many malaria RDTs have elevated FP rates against HAMA and RF positive samples practitioners may need to consider the possibility of false positive results for malaria in patients with conditions that stimulate HAMA or RF.

IgM rheumatoid factor removal and performance of the FTA-ABS (IgM) test in congenital syphilis.

PubMed

Meyer, M P; Roditi, D; Louw, S

1992-08-01

To determine the performance of the FTA-ABS (IgM) test in congenital syphilis after eliminating interference by IgM rheumatoid factor (RF) and preventing competitive inhibition by IgG. The FTA-ABS (IgM) test was carried out before and after RF removal (achieved by immunoprecipitation of the IgG) in infants with congenital syphilis and controls. Newborns delivered in the Peninsula Maternal and Neonatal Services in Cape Town and infants presenting at Red Cross War Memorial Children's Hospital. Infants with congenital syphilis aged 0-4 months were divided into those with clinical signs at presentation and those who were asymptomatic at delivery. In addition, patients without congenital syphilis but with similar clinical signs at presentation were investigated as were control infants. The diagnosis of congenital syphilis was based on the criteria suggested by Kaufman et al (1977). Amongst symptomatic infants with congenital syphilis the FTA-ABS (IgM) test was positive in 34 (92%) of 37 cases prior to abolishing the RF effect and in 29 (78.4%) of 37 cases afterwards (p = 0.19). In 12 cases of congenital syphilis who were asymptomatic at birth, 10 had positive FTA-ABS (IgM) tests before RF removal and only three had positive tests afterwards (p = 0.006). False positive tests were not found amongst 15 symptomatic infants whose clinical features mimicked those of the infants with congenital syphilis. Among 51 healthy infants the test had a false-positive rate of 2% in newborns and 13% in older infants. The false positive reactions were eradicated by IgG precipitation. Following IgG and RF removal there was an improvement in the specificity of the FTA-ABS (IgM) test but this was at the expense of a loss of sensitivity, particularly in asymptomatic newborns. For newborns, if the FTA-ABS (IgM) test was positive, the patient was likely to require treatment for congenital syphilis, regardless of whether the result was due to the presence of RF or specific IgM.

RF Energy Interaction With Electro-Optic Materials (Single Investigator Award Proposed to Address Research Topic Area 6.4. Electromagnetics and RF Circuit Integration)

DTIC Science & Technology

2015-12-27

demonstration vehicles. Test and measurement of fabricated structures will be conducted to experimentally quantify RF and optical performance. Measurement...the development of coupled RF and optical structures. Both the graduate student and the undergraduate student were trained in conducting precision...research conducted for this project. The journal paper citations are: 1. L. Chen, J. Nagy, and R. M. Reano, "Patterned ion-sliced lithium niobate for

Teaching Parents about Responsive Feeding through a Vicarious Learning Video: A Pilot Randomized Controlled Trial

ERIC Educational Resources Information Center

Ledoux, Tracey; Robinson, Jessica; Baranowski, Tom; O'Connor, Daniel P.

2018-01-01

The American Academy of Pediatrics and World Health Organization recommend responsive feeding (RF) to promote healthy eating behaviors in early childhood. This project developed and tested a vicarious learning video to teach parents RF practices. A RF vicarious learning video was developed using community-based participatory research methods.…

Design and Calibration of an RF Actuator for Low-Level RF Systems

NASA Astrophysics Data System (ADS)

Geng, Zheqiao; Hong, Bo

2016-02-01

X-ray free electron laser (FEL) machines like the Linac Coherent Light Source (LCLS) at SLAC require high-quality electron beams to generate X-ray lasers for various experiments. Digital low-level RF (LLRF) systems are widely used to control the high-power RF klystrons to provide a highly stable RF field in accelerator structures for beam acceleration. Feedback and feedforward controllers are implemented in LLRF systems to stabilize or adjust the phase and amplitude of the RF field. To achieve the RF stability and the accuracy of the phase and amplitude adjustment, low-noise and highly linear RF actuators are required. Aiming for the upgrade of the S-band Linac at SLAC, an RF actuator is designed with an I/Qmodulator driven by two digital-to-analog converters (DAC) for the digital LLRF systems. A direct upconversion scheme is selected for RF actuation, and an on-line calibration algorithm is developed to compensate the RF reference leakage and the imbalance errors in the I/Q modulator, which may cause significant phase and amplitude actuation errors. This paper presents the requirements on the RF actuator, the design of the hardware, the calibration algorithm, and the implementation in firmware and software and the test results at LCLS.

Compact rf polarizer and its application to pulse compression systems

DOE PAGES

Franzi, Matthew; Wang, Juwen; Dolgashev, Valery; ...

2016-06-01

We present a novel method of reducing the footprint and increasing the efficiency of the modern multi-MW rf pulse compressor. This system utilizes a high power rf polarizer to couple two circular waveguide modes in quadrature to a single resonant cavity in order to replicate the response of a traditional two cavity configuration using a 4-port hybrid. The 11.424 GHz, high-Q, spherical cavity has a 5.875 cm radius and is fed by the circularly polarized signal to simultaneously excite the degenerate TE 114 modes. The overcoupled spherical cavity has a Q 0 of 9.4×10 4 and coupling factor (β) ofmore » 7.69 thus providing a loaded quality factor Q L of 1.06×10 4 with a fill time of 150 ns. Cold tests of the polarizer demonstrated good agreement with the numerical design, showing transmission of -0.05 dB and reflection back to the input rectangular WR 90 waveguide less than -40 dB over a 100 MHz bandwidth. This novel rf pulse compressor was tested at SLAC using XL-4 Klystron that provided rf power up to 32 MW and generated peak output power of 205 MW and an average of 135 MW over the discharged signal. A general network analysis of the polarizer is discussed as well as the design and high power test of the rf pulse compressor.« less

Conference report on the 3rd International Symposium on Lithium Application for Fusion Devices

DOE PAGES

Mazzitelli, Guiseppe; Hirooka, Y.; Hu, J. S.; ...

2015-01-14

The third International Symposium on Lithium Application for Fusion Device (ISLA-2013) was held on 9-11 October 2013 at ENEA Frascati Centre with growing participation and interest from the community working on more general aspect of liquid metal research for fusion energy development. ISLA-2013 has been confirmed to be the largest and the most important meeting dedicated to liquid metal application for the magnetic fusion research. Overall, 45 presentation plus 5 posters were given, representing 28 institutions from 11 countries. The latest experimental results from nine magnetic fusion devices were presented in 16 presentations from NSTX (PPPL, USA), FTU (ENEA, Italy),more » T-11M (Trinity, RF), T-10 (Kurchatov Institute, RF), TJ-II (CIEMAT, Spain), EAST(ASIPP, China), HT-7 (ASIPP, China), RFX (Padova, Italy), KTM (NNC RK, Kazakhstan). Sessions were devoted to the following: (I) lithium in magnetic confinement experiments (facility overviews), (II) lithium in magnetic confinement experiments (topical issues), (III) special session on liquid lithium technology, (IV) lithium laboratory test stands, (V) Lithium theory/modelling/comments, (VI) innovative lithium applications and (VII) special Session on lithium-safety and lithium handling. There was a wide participation from the fusion technology communities, including IFMIF and TBM communities providing productive exchange with the physics oriented magnetic confinement liquid metal research groups. Furthermore, this international workshop will continue on a biennial basis (alternating with the Plasma-Surface Interactions (PSI) Conference) and the next workshop will be held at CIEMAT, Madrid, Spain, in 2015.« less

Conference Report on the 3rd International Symposium on Lithium Application for Fusion Devices

NASA Astrophysics Data System (ADS)

Mazzitelli, G.; Hirooka, Y.; Hu, J. S.; Mirnov, S. V.; Nygren, R.; Shimada, M.; Ono, M.; Tabares, F. L.

2015-02-01

The third International Symposium on Lithium Application for Fusion Device (ISLA-2013) was held on 9-11 October 2013 at ENEA Frascati Centre with growing participation and interest from the community working on more general aspect of liquid metal research for fusion energy development. ISLA-2013 has been confirmed to be the largest and the most important meeting dedicated to liquid metal application for the magnetic fusion research. Overall, 45 presentation plus 5 posters were given, representing 28 institutions from 11 countries. The latest experimental results from nine magnetic fusion devices were presented in 16 presentations from NSTX (PPPL, USA), FTU (ENEA, Italy), T-11M (Trinity, RF), T-10 (Kurchatov Institute, RF), TJ-II (CIEMAT, Spain), EAST(ASIPP, China), HT-7 (ASIPP, China), RFX (Padova, Italy), KTM (NNC RK, Kazakhstan). Sessions were devoted to the following: (I) lithium in magnetic confinement experiments (facility overviews), (II) lithium in magnetic confinement experiments (topical issues), (III) special session on liquid lithium technology, (IV) lithium laboratory test stands, (V) Lithium theory/modelling/comments, (VI) innovative lithium applications and (VII) special Session on lithium-safety and lithium handling. There was a wide participation from the fusion technology communities, including IFMIF and TBM communities providing productive exchange with the physics oriented magnetic confinement liquid metal research groups. This international workshop will continue on a biennial basis (alternating with the Plasma-Surface Interactions (PSI) Conference) and the next workshop will be held at CIEMAT, Madrid, Spain, in 2015.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mazzitelli, Guiseppe; Hirooka, Y.; Hu, J. S.

The third International Symposium on Lithium Application for Fusion Device (ISLA-2013) was held on 9-11 October 2013 at ENEA Frascati Centre with growing participation and interest from the community working on more general aspect of liquid metal research for fusion energy development. ISLA-2013 has been confirmed to be the largest and the most important meeting dedicated to liquid metal application for the magnetic fusion research. Overall, 45 presentation plus 5 posters were given, representing 28 institutions from 11 countries. The latest experimental results from nine magnetic fusion devices were presented in 16 presentations from NSTX (PPPL, USA), FTU (ENEA, Italy),more » T-11M (Trinity, RF), T-10 (Kurchatov Institute, RF), TJ-II (CIEMAT, Spain), EAST(ASIPP, China), HT-7 (ASIPP, China), RFX (Padova, Italy), KTM (NNC RK, Kazakhstan). Sessions were devoted to the following: (I) lithium in magnetic confinement experiments (facility overviews), (II) lithium in magnetic confinement experiments (topical issues), (III) special session on liquid lithium technology, (IV) lithium laboratory test stands, (V) Lithium theory/modelling/comments, (VI) innovative lithium applications and (VII) special Session on lithium-safety and lithium handling. There was a wide participation from the fusion technology communities, including IFMIF and TBM communities providing productive exchange with the physics oriented magnetic confinement liquid metal research groups. Furthermore, this international workshop will continue on a biennial basis (alternating with the Plasma-Surface Interactions (PSI) Conference) and the next workshop will be held at CIEMAT, Madrid, Spain, in 2015.« less

An RF dosimeter for independent SAR measurement in MRI scanners

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qian, Di; Bottomley, Paul A.; El-Sharkawy, AbdEl-Monem M.

2013-12-15

Purpose: The monitoring and management of radio frequency (RF) exposure is critical for ensuring magnetic resonance imaging (MRI) safety. Commercial MRI scanners can overestimate specific absorption rates (SAR) and improperly restrict clinical MRI scans or the application of new MRI sequences, while underestimation of SAR can lead to tissue heating and thermal injury. Accurate scanner-independent RF dosimetry is essential for measuring actual exposure when SAR is critical for ensuring regulatory compliance and MRI safety, for establishing RF exposure while evaluating interventional leads and devices, and for routine MRI quality assessment by medical physicists. However, at present there are no scanner-independentmore » SAR dosimeters. Methods: An SAR dosimeter with an RF transducer comprises two orthogonal, rectangular copper loops and a spherical MRI phantom. The transducer is placed in the magnet bore and calibrated to approximate the resistive loading of the scanner's whole-body birdcage RF coil for human subjects in Philips, GE and Siemens 3 tesla (3T) MRI scanners. The transducer loop reactances are adjusted to minimize interference with the transmit RF field (B{sub 1}) at the MRI frequency. Power from the RF transducer is sampled with a high dynamic range power monitor and recorded on a computer. The deposited power is calibrated and tested on eight different MRI scanners. Whole-body absorbed power vs weight and body mass index (BMI) is measured directly on 26 subjects. Results: A single linear calibration curve sufficed for RF dosimetry at 127.8 MHz on three different Philips and three GE 3T MRI scanners. An RF dosimeter operating at 123.2 MHz on two Siemens 3T scanners required a separate transducer and a slightly different calibration curve. Measurement accuracy was ∼3%. With the torso landmarked at the xiphoid, human adult whole‑body absorbed power varied approximately linearly with patient weight and BMI. This indicates that whole-body torso SAR is on average independent of the imaging subject, albeit with fluctuations. Conclusions: Our 3T RF dosimeter and transducers accurately measure RF exposure in body-equivalent loads and provide scanner-independent assessments of whole-body RF power deposition for establishing safety compliance useful for MRI sequence and device testing.« less

2. EAST ELEVATION OF POWER PLANT TEST STAND (HORIZONTAL TEST ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. EAST ELEVATION OF POWER PLANT TEST STAND (HORIZONTAL TEST STAND REMNANTS OF BUILDING-BLANK WHITE WALL ONLY ORIGINAL REMAINS. - Marshall Space Flight Center, East Test Area, Power Plant Test Stand, Huntsville, Madison County, AL

Blocking effect of rheumatoid factor and cold agglutinins on complement fixation tests for histoplasmosis.

PubMed Central

Johnson, J E; Roberts, G D

1976-01-01

The blocking effect of rheumatoid factor (RF) and cold agglutinins (CA) on the detection of complement-fixing (CF) antibodies for Histoplasma capsulatum using a mycelial (histoplasmin) and a yeast antigen was studied. Sera from 213 patients serologically positive for histoplasmosis were screened for the presence of RF or CA. CF antibodies to H. capsulatum in sera containing RF or CA were studied before and after removal of these factors (RF and CA) by treatment with dithiothreitol. Results suggest that RF or CA may interfere with the CF reaction to the yeast antigen of H. capsulatum but not to the mycelial antigen (histoplasmin). PMID:1254713

Development of a Radio Frequency Space Environment Path Emulator for Evaluating Spacecraft Ranging Hardware

NASA Technical Reports Server (NTRS)

Mitchell, Jason W.; Baldwin, Philip J.; Kurichh, Rishi; Naasz, Bo J.; Luquette, Richard J.

2007-01-01

The Formation Flying Testbed (FFTB) at the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) provides a hardware-in-the-loop test environment for formation navigation and control. The facility is evolving as a modular, hybrid, dynamic simulation facility for end-to-end guidance, navigation and. control (GN&C) design and analysis of formation flying spacecraft. The core capabilities of the FFTB, as a platform for testing critical hardware and software algorithms in-the-loop, have expanded to include S-band Radio Frequency (RF) modems for inter-spacecraft communication and ranging. To enable realistic simulations that require RF ranging sensors for relative navigation, a mechanism is needed to buffer the RF signals exchanged between spacecraft that accurately emulates the dynamic environment through which the RF signals travel, including the effects of medium, moving platforms, and radiated power. The Path Emulator for RF Signals (PERFS), currently under development at NASA GSFC, provides this capability. The function and performance of a prototype device are presented.

Association between the MMPI-2 restructured form (MMPI-2-RF) and malingered neurocognitive dysfunction among non-head injury disability claimants.

PubMed

Tarescavage, Anthony M; Wygant, Dustin B; Gervais, Roger O; Ben-Porath, Yossef S

2013-01-01

The current study examined the over-reporting Validity Scales of the MMPI-2 Restructured Form (MMPI-2-RF; Ben-Porath & Tellegen, 2008/2011) in relation to the Slick, Sherman, and Iverson (1999) criteria for the diagnosis of Malingered Neurocognitive Dysfunction in a sample of 916 consecutive non-head injury disability claimants. The classification of Malingered Neurocognitive Dysfunction was based on scores from several cognitive symptom validity tests and response bias indicators built into traditional neuropsychological tests. Higher scores on MMPI-2-RF Validity Scales, particularly the Response Bias Scale (Gervais, Ben-Porath, Wygant, & Green, 2007), were associated with probable and definite Malingered Neurocognitive Dysfunction. The MMPI-2-RF's Validity Scales classification accuracy of Malingered Neurocognitive Dysfunction improved when multiple scales were interpreted. Additionally, higher scores on MMPI-2-RF substantive scales measuring distress, internalizing dysfunction, thought dysfunction, and social avoidance were associated with probable and definite Malingered Neurocognitive Dysfunction. Implications for clinical practice and future directions are noted.

Transport of ions using RF Carpets in Helium Gas

NASA Astrophysics Data System (ADS)

Lambert, Keenan; Kelly, James; Brodeur, Maxime

2017-09-01

Radio-Frequency (RF) carpet are critical components of large volume gas cells used to thermalize radioactive ion beams produced at in-flight facilities. RF carpets are formed by a series of co-centric conductive rings on which an alternating potential (in the radio-frequency range) is applied with opposite polarity on adjacent rings. This results in a strong repelling force that keep the ions a certain distance from the carpet. The transport of ions using RF carpet is accomplished using either a potential gradient applied on the individual all strips or traveling wave (using the so-called `ion surfing method'). A test setup has been constructed at the University of Notre Dame to perform studies on the repelling of ions using RF carpets. This test setup has recently been improved by the addiction of circuitry elements allowing the transport of ions using the ion surfing method. The developed circuitry, together with transport results for various ion beam currents, electric force applied on the ions, and traveling wave amplitude and speed will be presented

Analytical & Experimental Study of Radio Frequency Cavity Beam Profile Monitor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balcazar, Mario D.; Yonehara, Katsuya

The purpose of this analytical and experimental study is multifold: 1) To explore a new, radiation-robust, hadron beam profile monitor for intense neutrino beam applications; 2) To test, demonstrate, and develop a novel gas-filled Radio-Frequency (RF) cavity to use in this monitoring system. Within this context, the first section of the study analyzes the beam distribution across the hadron monitor as well as the ion-production rate inside the RF cavity. Furthermore a more effecient pixel configuration across the hadron monitor is proposed to provide higher sensitivity to changes in beam displacement. Finally, the results of a benchtop test of themore » tunable quality factor RF cavity will be presented. The proposed hadron monitor configuration consists of a circular array of RF cavities located at a radial distance of 7cm { corresponding to the standard deviation of the beam due to scatering { and a gas-filled RF cavity with a quality factor in the range 400 - 800.« less

Pulsed beam tests at the SANAEM RFQ beamline

NASA Astrophysics Data System (ADS)

Turemen, G.; Akgun, Y.; Alacakir, A.; Kilic, I.; Yasatekin, B.; Ergenlik, E.; Ogur, S.; Sunar, E.; Yildiz, V.; Ahiska, F.; Cicek, E.; Unel, G.

2017-07-01

A proton beamline consisting of an inductively coupled plasma (ICP) source, two solenoid magnets, two steerer magnets and a radio frequency quadrupole (RFQ) is developed at the Turkish Atomic Energy Authority’s (TAEA) Saraykoy Nuclear Research and Training Center (SNRTC-SANAEM) in Ankara. In Q4 of 2016, the RFQ was installed in the beamline. The high power tests of the RF power supply and the RF transmission line were done successfully. The high power RF conditioning of the RFQ was performed recently. The 13.56 MHz ICP source was tested in two different conditions, CW and pulsed. The characterization of the proton beam was done with ACCTs, Faraday cups and a pepper-pot emittance meter. Beam transverse emittance was measured in between the two solenoids of the LEBT. The measured beam is then reconstructed at the entrance of the RFQ by using computer simulations to determine the optimum solenoid currents for acceptance matching of the beam. This paper will introduce the pulsed beam test results at the SANAEM RFQ beamline. In addition, the high power RF conditioning of the RFQ will be discussed.

Qualification testing of solar photovoltaic powered refrigerator freezers for medical use in remote geographic locations

NASA Astrophysics Data System (ADS)

Kaszeta, W. J.

1982-12-01

One of the primary obstacles to the application of vaccination in developing countries is the lack of refrigerated storage. Vaccines exposed to elevated temperatures suffer a permanent loss of potency. Photovoltaic (PV) powered refrigerator/freezer (R/F) units could surmount the problem of refrigeration in remote areas where no reliable commercial power supply is available. The performance measurements of two different models of PV powered R/F units for medical use are presented. Qualification testing consisted of four major procedures: no-load pull down, ice making, steady-state (maintenance), and holdover. Both R/F units met the major World Health Organization (WHO) requirements. However, the testing performed does not provide complete characterization of the two units; such information could be derived only from further extensive test procedures.

Qualification testing of solar photovoltaic powered refrigerator freezers for medical use in remote geographic locations

NASA Technical Reports Server (NTRS)

Kaszeta, W. J.

1982-01-01

One of the primary obstacles to the application of vaccination in developing countries is the lack of refrigerated storage. Vaccines exposed to elevated temperatures suffer a permanent loss of potency. Photovoltaic (PV) powered refrigerator/freezer (R/F) units could surmount the problem of refrigeration in remote areas where no reliable commercial power supply is available. The performance measurements of two different models of PV powered R/F units for medical use are presented. Qualification testing consisted of four major procedures: no-load pull down, ice making, steady-state (maintenance), and holdover. Both R/F units met the major World Health Organization (WHO) requirements. However, the testing performed does not provide complete characterization of the two units; such information could be derived only from further extensive test procedures.

CAT/RF Simulation Lessons Learned

DTIC Science & Technology

2003-06-11

IVSS-2003-MAS-7 CAT /RF Simulation Lessons Learned Christopher Mocnik Vetronics Technology Area, RDECOM TARDEC Tim Lee DCS Corporation...developed a re- configurable Unmanned Ground Vehicle (UGV) simulation for the Crew integration and Automation Test bed ( CAT ) and Robotics Follower (RF...Advanced Technology Demonstration (ATD) experiments. This simulation was developed as a component of the Embedded Simulation System (ESS) of the CAT

Psychometric Properties of the MMPI-2-RF Somatic Complaints (RC1) Scale

ERIC Educational Resources Information Center

Thomas, Michael L.; Locke, Dona E. C.

2010-01-01

The MMPI-2 Restructured Form (MMPI-2-RF; Tellegen & Ben-Porath, 2008) was designed to be psychometrically superior to its MMPI-2 counterpart. However, the test has yet to be extensively evaluated in diverse clinical settings. The purpose of this study was to examine the psychometric properties of the MMPI-2-RF Somatic Complaints (RC1) scale in…

Real-time cavity simulator-based low-level radio-frequency test bench and applications for accelerators

NASA Astrophysics Data System (ADS)

Qiu, Feng; Michizono, Shinichiro; Miura, Takako; Matsumoto, Toshihiro; Liu, Na; Wibowo, Sigit Basuki

2018-03-01

A Low-level radio-frequency (LLRF) control systems is required to regulate the rf field in the rf cavity used for beam acceleration. As the LLRF system is usually complex, testing of the basic functions or control algorithms of this system in real time and in advance of beam commissioning is strongly recommended. However, the equipment necessary to test the LLRF system, such as superconducting cavities and high-power rf sources, is very expensive; therefore, we have developed a field-programmable gate array (FPGA)-based cavity simulator as a substitute for real rf cavities. Digital models of the cavity and other rf systems are implemented in the FPGA. The main components include cavity baseband models for the fundamental and parasitic modes, a mechanical model of the Lorentz force detuning, and a model of the beam current. Furthermore, in our simulator, the disturbance model used to simulate the power-supply ripples and microphonics is also carefully considered. Based on the presented cavity simulator, we have established an LLRF system test bench that can be applied to different cavity operational conditions. The simulator performance has been verified by comparison with real cavities in KEK accelerators. In this paper, the development and implementation of this cavity simulator is presented first, and the LLRF test bench based on the presented simulator is constructed. The results are then compared with those for KEK accelerators. Finally, several LLRF applications of the cavity simulator are illustrated.

28. HISTORIC VIEW OF A3 ROCKET IN TEST STAND NO. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

28. HISTORIC VIEW OF A-3 ROCKET IN TEST STAND NO. 3 AT KUMMERSDORF (THE LARGEST TEST STAND AT KUMMERSDORF). THE STAND WAS MOBILE, SINCE IT MOVED ALONG RAILS. - Marshall Space Flight Center, Redstone Rocket (Missile) Test Stand, Dodd Road, Huntsville, Madison County, AL

1. TEST STAND 1A ENVIRONS, SHOWING WEST SIDE OF TEST ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. TEST STAND 1-A ENVIRONS, SHOWING WEST SIDE OF TEST STAND 1-A, RP1 COMBINED FUEL STORAGE TANK FARM BELOW WATER TANKS ON HILLSIDE TO LEFT, AND TEST STAND 1-B IN DISTANCE AT RIGHT. Looking east. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-A, Test Area 1-120, north end of Jupiter Boulevard, Boron, Kern County, CA

High temperature UF6 RF plasma experiments applicable to uranium plasma core reactors

NASA Technical Reports Server (NTRS)

Roman, W. C.

1979-01-01

An investigation was conducted using a 1.2 MW RF induction heater facility to aid in developing the technology necessary for designing a self critical fissioning uranium plasma core reactor. Pure, high temperature uranium hexafluoride (UF6) was injected into an argon fluid mechanically confined, steady state, RF heated plasma while employing different exhaust systems and diagnostic techniques to simulate and investigate some potential characteristics of uranium plasma core nuclear reactors. The development of techniques and equipment for fluid mechanical confinement of RF heated uranium plasmas with a high density of uranium vapor within the plasma, while simultaneously minimizing deposition of uranium and uranium compounds on the test chamber peripheral wall, endwall surfaces, and primary exhaust ducts, is discussed. The material tests and handling techniques suitable for use with high temperature, high pressure, gaseous UF6 are described and the development of complementary diagnostic instrumentation and measurement techniques to characterize the uranium plasma, effluent exhaust gases, and residue deposited on the test chamber and exhaust system components is reported.

Studies and optimization of Pohang Light Source-II superconducting radio frequency system at stable top-up operation with beam current of 400 mA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Joo, Youngdo, E-mail: Ydjoo77@postech.ac.kr; Yu, Inha; Park, Insoo

After three years of upgrading work, the Pohang Light Source-II (PLS-II) is now successfully operating. The final quantitative goal of PLS-II is a top-up user-service operation with beam current of 400 mA to be completed by the end of 2014. During the beam store test up to 400 mA in the storage ring (SR), it was observed that the vacuum pressure around the radio frequency (RF) window of the superconducting cavity rapidly increases over the interlock level limiting the availability of the maximum beam current storing. Although available beam current is enhanced by setting a higher RF accelerating voltage, it is bettermore » to keep the RF accelerating voltage as low as possible in the long time top-up operation. We investigated the cause of the window vacuum pressure increment by studying the changes in the electric field distribution at the superconducting cavity and waveguide according to the beam current. In our simulation, an equivalent physical modeling was developed using a finite-difference time-domain code. The simulation revealed that the electric field amplitude at the RF window is exponentially increased as the beam current increases, thus this high electric field amplitude causes a RF breakdown at the RF window, which comes with the rapid increase of window vacuum pressure. The RF accelerating voltage of PLS-II RF system was set to 4.95 MV, which was estimated using the maximum available beam current that works as a function of RF voltage, and the top-up operation test with the beam current of 400 mA was successfully carried out.« less

HLA-DRB1 Analysis Identified a Genetically Unique Subset within Rheumatoid Arthritis and Distinct Genetic Background of Rheumatoid Factor Levels from Anticyclic Citrullinated Peptide Antibodies.

PubMed

Hiwa, Ryosuke; Ikari, Katsunori; Ohmura, Koichiro; Nakabo, Shuichiro; Matsuo, Keitaro; Saji, Hiroh; Yurugi, Kimiko; Miura, Yasuo; Maekawa, Taira; Taniguchi, Atsuo; Yamanaka, Hisashi; Matsuda, Fumihiko; Mimori, Tsuneyo; Terao, Chikashi

2018-04-01

HLA-DRB1 is the most important locus associated with rheumatoid arthritis (RA) and anticitrullinated protein antibodies (ACPA). However, fluctuations of rheumatoid factor (RF) over the disease course have made it difficult to define fine subgroups according to consistent RF positivity for the analyses of genetic background and the levels of RF. A total of 2873 patients with RA and 2008 healthy controls were recruited. We genotyped HLA-DRB1 alleles for the participants and collected consecutive data of RF in the case subjects. In addition to RF+ and RF- subsets, we classified the RF+ subjects into group 1 (constant RF+) and group 2 (seroconversion). We compared HLA-DRB1 alleles between the RA subsets and controls and performed linear regression analysis to identify HLA-DRB1 alleles associated with maximal RF levels. Omnibus tests were conducted to assess important amino acid positions. RF positivity was 88%, and 1372 and 970 RF+ subjects were classified into groups 1 and 2, respectively. RF+ and RF- showed similar genetic associations to ACPA+ and ACPA- RA, respectively. We found that shared epitope (SE) was more enriched in group 2 than 1, p = 2.0 × 10 -5 , and that amino acid position 11 showed a significant association between 1 and 2, p = 2.7 × 10 -5 . These associations were independent of ACPA positivity. SE showed a tendency to be negatively correlated with RF titer (p = 0.012). HLA-DRB1*09:01, which reduces ACPA titer, was not associated with RF levels (p = 0.70). The seroconversion group was shown to have distinct genetic characteristics. The genetic architecture of RF levels is different from that of ACPA.

Performance of machine-learning scoring functions in structure-based virtual screening.

PubMed

Wójcikowski, Maciej; Ballester, Pedro J; Siedlecki, Pawel

2017-04-25

Classical scoring functions have reached a plateau in their performance in virtual screening and binding affinity prediction. Recently, machine-learning scoring functions trained on protein-ligand complexes have shown great promise in small tailored studies. They have also raised controversy, specifically concerning model overfitting and applicability to novel targets. Here we provide a new ready-to-use scoring function (RF-Score-VS) trained on 15 426 active and 893 897 inactive molecules docked to a set of 102 targets. We use the full DUD-E data sets along with three docking tools, five classical and three machine-learning scoring functions for model building and performance assessment. Our results show RF-Score-VS can substantially improve virtual screening performance: RF-Score-VS top 1% provides 55.6% hit rate, whereas that of Vina only 16.2% (for smaller percent the difference is even more encouraging: RF-Score-VS top 0.1% achieves 88.6% hit rate for 27.5% using Vina). In addition, RF-Score-VS provides much better prediction of measured binding affinity than Vina (Pearson correlation of 0.56 and -0.18, respectively). Lastly, we test RF-Score-VS on an independent test set from the DEKOIS benchmark and observed comparable results. We provide full data sets to facilitate further research in this area (http://github.com/oddt/rfscorevs) as well as ready-to-use RF-Score-VS (http://github.com/oddt/rfscorevs_binary).

A preliminary identification of Rf*-A619, a novel restorer gene for CMS-C in maize (Zea mays L.).

PubMed

Yongming, Liu; Zhuofan, Zhao; Yanli, Lu; Chuan, Li; Jing, Wang; Boxiao, Dong; Bing, Liang; Tao, Qiu; Wenbing, Zeng; Moju, Cao

2016-01-01

C-type cytoplasmic male sterility (CMS-C) is widely utilized for hybrid maize seed production. However, genetic mechanisms underlying the fertility restoration are very complicated. At present, there is a divergence on the number of fertility restorer genes in maize inbred line A619 for CMS-C. To further elucidate the restoring mechanism of A619, we used genetic analysis and molecular markers to confirm the restorer genes of maize inbred line A619 for C-type male sterile line C48-2 in this study. Firstly, the fertility segregations of (C48-2 × A619)F 2 populations were investigated under three environments during 2013-2015. The segregation ratio of fertile and sterile plants in the F 2 population fit to 15:1 via chi-square test and this result suggested that there are two dominant restorer genes in A619 for CMS-C, i.e., Rf4 and a novel gene named Rf*-A619 . Next, based on the sequence differences between Rf4 and its recessive allelic rf4 , a novel dominant marker F2/R2 was developed and validated to genotyping Rf4 in the F 2 population. Through genotypic analysis, we found that there were a certain amount of fertile individuals without Rf4 which accounted for 3/16 in the F 2 population via chi-square test at the 0.05 level. These results provided another proof to sustain that the inbred line A619 contains one additional restorer gene for CMS-C fertility restoration except Rf4 . At last, we used one SSR marker which is tightly linked with the dominant restorer gene Rf5 to analyze those fertile plants without Rf4 in the F 2 population. The PCR amplification results showed that Rf*-A619 is not allelic to Rf5 but a novel restorer gene for CMS-C. These results not only provide a basis for the mapping and characterization of a novel restorer gene but also give a new insight into the mechanism of CMS-C fertility restoration.

Porcine MuRF2 and MuRF3: molecular cloning, expression and association analysis with muscle production traits.

PubMed

Shen, H; Zhao, S H; Cao, J H; Li, X Y; Fan, B

2011-11-01

Muscle specific RING finger protein2 (MuRF2) and Muscle specific RING finger protein3(MuRF3) are two important members of the muscle specific RING finger protein family, which are especially expressed in cardiac and skeletal muscle tissues and play critical roles during the myocyte differentiation, development and morphogenesis. In this study, the molecular characteristics of porcine MuRF2 and MuRF3 gene were reported, and furthermore two variants of MuRF2 were identified. The tissue distribution pattern analyses revealed that MuRF2-b and MuRF3 mRNA was exclusively expressed in striated muscle tissues while MuRF2-a had a low-level expression in liver tissue. Real-time quantitative reverse transcriptase-polymerase chain reaction (RT-qPCR) results displayed MuRF2 mRNA expression levels were significantly varied at three stages of fetal skeletal muscle in Landrace pigs, and the expression of MuRF2-a was lower than that of MuRF2-b in all stages. An essencial region of -396 to -22 for transcription was identified at the 5'UTR of porcine MuRF2 gene, while no active regulatory fragment found in the 5'UTR of mouse MuRF2. A single nucleotide polymorphism (SNP), c.915G > A was identified in MuRF2 exon 5. A HinfI PCR-RFLP was developed for SNP genotyping in two different pig populations. Association of the genotypes with growth and carcass traits showed that different genotypes of MuRF2 were significantly (P < 0.05) associated with average daily gain on test, carcass weight and carcass length. The study suggested that the porcine MuRF2 and MuRF3 genes are involved in the muscle growth and development, and can be considered as potential candidate genes affecting muscle production traits in the pig.

Radiofrequency heating of metallic dental devices during 3.0 T MRI

PubMed Central

Hasegawa, M; Miyata, K; Abe, Y; Ishigami, T

2013-01-01

Objectives: To estimate the risk of injury from radiofrequency (RF) heating of metallic dental devices in use during 3.0 T MRI. Methods: The whole-body specific absorption rate (WB-SAR) was calculated on the basis of saline temperature elevation under the maximum RF irradiation for 15 min to determine the operation parameters for the heating test. The temperature changes of three types of three-unit bridges, a full-arch fixed dental prosthesis and an orthodontic appliance in use during MRI with a 3.0 T MR system (Magnetom® Verio; Siemens AG, Erlangen, Germany) were then tested in accordance with the American Society for Testing and Materials F2182-09 standardized procedure under the maximum RF heating during 15 min RF irradiation. Results: The system console-predicted WB-SAR was approximately 1.4 W kg−1 and that measured with a saline phantom was 2.1 W kg−1. In the assessment of RF heating, the highest temperature increase was +1.80 °C in the bridges, +1.59 °C in the full-arch fixed dental prosthesis and +2.61 °C in the orthodontic appliance. Conclusions: The relatively minor RF heating of dental casting material-based prostheses in Magnetom Verio systems in the normal operating mode should not pose a risk to patients. However, orthodontic appliances may exhibit RF heating above the industrial standard (CENELEC standard prEN45502-2-3); therefore, the wire should be removed from the bracket or a spacer should be used between the appliance and the oral mucosa during MRI. PMID:23520391

A modified quadrupole mass spectrometer with custom RF link rods driver for remote operation

NASA Technical Reports Server (NTRS)

Tashbar, P. W.; Nisen, D. B.; Moore, W. W., Jr.

1973-01-01

A commercial quadrupole residual gas analyzer system has been upgraded for operation at extended cable lengths. Operation inside a vacuum chamber for the standard quadrupole nude head is limited to approximately 2 m from its externally located rf/dc generator because of the detuning of the rf oscillator circuits by the coaxial cable reactance. The advance of long distance remote operation inside a vacuum chamber for distances of 45 and 60 m was made possible without altering the quadrupole's rf/dc generator circuit by employing an rf link to drive the quadrupole rods. Applications of the system have been accomplished for in situ space simulation thermal/vacuum testing of sophisticated payloads.

20. Building 202, detail of stand A, rocket test stand ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

20. Building 202, detail of stand A, rocket test stand in test cell. View looking southeast. - Rocket Engine Testing Facility, GRC Building No. 202, NASA Glenn Research Center, Cleveland, Cuyahoga County, OH

31. HISTORIC VIEW OF TEST STAND NO. 1 AT PEENEMUENDE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

31. HISTORIC VIEW OF TEST STAND NO. 1 AT PEENEMUENDE A-4 ENGINE AND ROCKET PROPULSION TEST STAND. - Marshall Space Flight Center, Redstone Rocket (Missile) Test Stand, Dodd Road, Huntsville, Madison County, AL

Upgrade of the cryogenic infrastructure of SM18, CERN main test facility for superconducting magnets and RF cavities

NASA Astrophysics Data System (ADS)

Perin, A.; Dhalla, F.; Gayet, P.; Serio, L.

2017-12-01

SM18 is CERN main facility for testing superconducting accelerator magnets and superconducting RF cavities. Its cryogenic infrastructure will have to be significantly upgraded in the coming years, starting in 2019, to meet the testing requirements for the LHC High Luminosity project and for the R&D program for superconducting magnets and RF equipment until 2023 and beyond. This article presents the assessment of the cryogenic needs based on the foreseen test program and on past testing experience. The current configuration of the cryogenic infrastructure is presented and several possible upgrade scenarios are discussed. The chosen upgrade configuration is then described and the characteristics of the main newly required cryogenic equipment, in particular a new 35 g/s helium liquefier, are presented. The upgrade implementation strategy and plan to meet the required schedule are then described.

An Optical Receiver Post Processing System for the Integrated Radio and Optical Communications Software Defined Radio Test Bed

NASA Technical Reports Server (NTRS)

Nappier, Jennifer M.; Tokars, Roger P.; Wroblewski, Adam C.

2016-01-01

The Integrated Radio and Optical Communications (iROC) project at the National Aeronautics and Space Administrations (NASA) Glenn Research Center is investigating the feasibility of a hybrid radio frequency (RF) and optical communication system for future deep space missions. As a part of this investigation, a test bed for a radio frequency (RF) and optical software defined radio (SDR) has been built. Receivers and modems for the NASA deep space optical waveform are not commercially available so a custom ground optical receiver system has been built. This paper documents the ground optical receiver, which is used in order to test the RF and optical SDR in a free space optical communications link.

An Optical Receiver Post-Processing System for the Integrated Radio and Optical Communications Software Defined Radio Test Bed

NASA Technical Reports Server (NTRS)

Nappier, Jennifer M.; Tokars, Roger P.; Wroblewski, Adam C.

2016-01-01

The Integrated Radio and Optical Communications (iROC) project at the National Aeronautics and Space Administration's (NASA) Glenn Research Center is investigating the feasibility of a hybrid radio frequency (RF) and optical communication system for future deep space missions. As a part of this investigation, a test bed for a radio frequency (RF) and optical software defined radio (SDR) has been built. Receivers and modems for the NASA deep space optical waveform are not commercially available so a custom ground optical receiver system has been built. This paper documents the ground optical receiver, which is used in order to test the RF and optical SDR in a free space optical communications link.

GENERAL VIEW OF SITE LOOKING SOUTHWEST. JUPITER 'HOP' STAND, FOREGROUND ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

GENERAL VIEW OF SITE LOOKING SOUTHWEST. JUPITER 'HOP' STAND, FOREGROUND CENTER, REDSTONE TEST STAND FOREGROUND RIGHT, SATURN I C TEST STAND BACKGROUND LEFT. - Marshall Space Flight Center, Redstone Rocket (Missile) Test Stand, Dodd Road, Huntsville, Madison County, AL

Alternative refrigerants and refrigeration cycles for domestic refrigerators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sand, J.R.; Rice, C.L.; Vineyard, E.A.

1992-12-01

This project initially focused on using nonazeotropic refrigerant mixtures (NARMs) in a two-evaporator refrigerator-freezer design using two stages of liquid refrigerant subcooling. This concept was proposed and tested in 1975. The work suggested that the concept was 20% more efficient than the conventional one-evaporator refrigerator-freezer (RF) design. After considerable planning and system modeling based on using a NARM in a Lorenz-Meutzner (L-M) RF, the program scope was broadened to include investigation of a ``dual-loop`` concept where energy savings result from exploiting the less stringent operating conditions needed to satisfy cooling, of the fresh food section. A steady-state computer model (CYCLE-Z)more » capable of simulating conventional, dual loop, and L-M refrigeration cycles was developed. This model was used to rank the performance of 20 ozone-safe NARMs in the L-M refrigeration cycle while key system parameters were systematically varied. The results indicated that the steady-state efficiency of the L-M design was up to 25% greater than that of a conventional cycle. This model was also used to calculate the performance of other pure refrigerants relative to that of dichlorodifluoromethane, R-12, in conventional and dual-loop RF designs. Projected efficiency gains for these cycles were more modest, ranging from 0 to 10%. Individual compressor calorimeter tests of nine combinations of evaporator and condenser temperatures usually used to map RF compressor performance were carried out with R-12 and two candidate L-M NARMs in several compressors. Several models of a commercially produced two-evaporator RF were obtained as test units. Two dual-loop RF designs were built and tested as part of this project.« less

Accuracy of Voltage Signal Measurement During Radiofrequency Delivery Through the SMARTTOUCH Catheter.

PubMed

Safavi-Naeini, Payam; Zafar-Awan, Dreema; Zhu, Hongjian; Zablah, Gerardo; Ganapathy, Anand V; Rasekh, Abdi; Saeed, Mohammad; Razavi, Joanna Esther Molina; Razavi, Mehdi

2017-01-01

Current methods for measuring voltage during radiofrequency (RF) ablation (RFA) necessitate turning off the ablation catheter. If voltage could be accurately read without signal attenuation during RFA, turning off the catheter would be unnecessary, allowing continuous ablation. We evaluated the accuracy of the Thermocool SMARTTOUCH catheter for measuring voltage while RF traverses the catheter. We studied 26 patients undergoing RFA for arrhythmias. A 7.5F SMARTTOUCH catheter was used for sensing voltage and performing RFA. Data were collected from the Carto-3 3-dimensional mapping system. Voltages were measured during ablation (RF-ON) and immediately before or after ablation (RF-OFF). In evaluating the accuracy of RF-ON measurements, we utilized the RF-OFF measure as the gold standard. We measured 465 voltage signals. The median values were 0.2900 and 0.3100 for RF-ON and RF-OFF, respectively. Wilcoxon signed rank testing showed no significant difference in these values (P = 0.608). The intraclass correlation coefficient (ICC) was 0.96, indicating that voltage measurements were similarly accurate during RF-OFF versus RF-ON. Five patients had baseline atrial fibrillation (AF), for whom 82 ablation points were measured; 383 additional ablation points were measured for the remaining patients. The voltages measured during RF-ON versus RF-OFF were similar in the presence of AF (P = 0.800) versus non-AF rhythm (P = 0.456) (ICC, 0.96 for both). Voltage signal measurement was similarly accurate during RF-ON versus RF-OFF independent of baseline rhythm. Physicians should consider not turning off the SMARTTOUCH ablation catheter when measuring voltage during RFA. © 2016 Wiley Periodicals, Inc.

Refined beam measurements on the SNS H- injector

NASA Astrophysics Data System (ADS)

Han, B. X.; Welton, R. F.; Murray, S. N.; Pennisi, T. R.; Santana, M.; Stinson, C. M.; Stockli, M. P.

2017-08-01

The H- injector for the SNS RFQ accelerator consists of an RF-driven, Cs-enhanced H- ion source and a compact, two-lens electrostatic LEBT. The LEBT output and the RFQ input beam current are measured by deflecting the beam on to an annular plate at the RFQ entrance. Our method and procedure have recently been refined to improve the measurement reliability and accuracy. The new measurements suggest that earlier measurements tended to underestimate the currents by 0-2 mA, but essentially confirm H- beam currents of 50-60 mA being injected into the RFQ. Emittance measurements conducted on a test stand featuring essentially the same H- injector setup show that the normalized rms emittance with 0.5% threshold (99% inclusion of the total beam) is in a range of 0.25-0.4 mm.mrad for a 50-60 mA beam. The RFQ output current is monitored with a BCM toroid. Measurements as well as simulations with the PARMTEQ code indicate an underperforming transmission of the RFQ since around 2012.

Next Generation H- Ion Sources for the SNS

NASA Astrophysics Data System (ADS)

Welton, R. F.; Stockli, M. P.; Murray, S. N.; Crisp, D.; Carmichael, J.; Goulding, R. H.; Han, B.; Tarvainen, O.; Pennisi, T.; Santana, M.

2009-03-01

The U.S. Spallation Neutron Source (SNS) is the leading accelerator-based, pulsed neutron-scattering facility, currently in the process of ramping up neutron production. In order to insure meeting operational requirements as well as providing for future facility beam power upgrades, a multifaceted H- ion source development program is ongoing. This work discusses several aspects of this program, specifically the design and first beam measurements of an RF-driven, external antenna H- ion source based on an A1N ceramic plasma chamber, elemental and chromate Cs-systems, and plasma ignition gun. Unanalyzed beam currents of up to ˜100 mA (60 Hz, 1 ms) have been observed and sustained currents >60 mA (60 Hz, 1 ms) have been demonstrated on the test stand. Accelerated beam currents of ˜40 mA have also been demonstrated into the SNS front end. Data are also presented describing the first H- beam extraction experiments from a helicon plasma generator based on the Variable Specific Impulse Magnetoplasma Rocket (VASIMR) engine design.

A Response to Odland et al.'s Misleading, Alarmist Estimates of Risk for Overpathologizing when Interpreting the MMPI-2-RF.

PubMed

Tarescavage, Anthony M; Ben-Porath, Yossef S

2015-01-01

In a recently published article in this journal, Odland, Lammy, Perle, Martin, and Grote report Monte Carlo-simulated normative base rates of scale elevations on the Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF). Their primary conclusion--reflected in the title of their article--is that MMPI-2-RF interpretation is associated with "high risk of pathologizing healthy adults" when the 40 substantive scales of the test are simultaneously interpreted. In this paper, we describe how their conclusion follows from several faulty premises, three of which were already debunked in an earlier article and remain false despite counterarguments proposed by Odland and colleagues. We also address these authors' misinterpretation of their analyses and, furthermore, their premise that MMPI-2-RF interpretive guidelines are flawed because they "currently do not account for a basic statistical principle: Type I (or alpha) error inflation" (p. 1). This premise is irrelevant to psychological test interpretation and misaligned with neuropsychological testing literature cited in support of it. Consistent with suggestions by some of the authors they cite, we reiterate MMPI-2-RF interpretive guidelines designed to mitigate the impact of measurement error (not alpha error) by way of a scientific assessment approach that relies on integration of information derived from multiple sources.

A Systematic Review of Serum Biomarkers Anti-Cyclic Citrullinated Peptide and Rheumatoid Factor as Tests for Rheumatoid Arthritis

PubMed Central

Taylor, Peter; Gartemann, Juliane; Hsieh, Jeanie; Creeden, James

2011-01-01

This systematic review assesses the current status of anti-cyclic citrullinated peptide (anti-CCP) and rheumatoid factor (RF) tests in the diagnosis and prognosis of rheumatoid arthritis (RA). We reviewed publications on tests and biomarkers for early diagnosis of RA from English-language MEDLINE-indexed journals and non-MEDLINE-indexed sources. 85 publications were identified and reviewed, including 68 studies from MEDLINE and 17 non-MEDLINE sources. Anti-CCP2 assays provide improved sensitivity over anti-CCP assays and RF, but anti-CCP2 and RF assays in combination demonstrate a positive predictive value (PPV) nearing 100%, greater than the PPV of either of the tests alone. The combination also appears to be able to distinguish between patients whose disease course is expected to be more severe and both tests are incorporated in the 2010 ACR Rheumatoid Arthritis Classification Criteria. While the clinical value of anti-CCP tests has been established, differences in cut-off values, sensitivities and specificities exist between first-, second- and third-generation tests and harmonization efforts are under way. Anti-CCP and RF are clinically valuable biomarkers for the diagnosis and prognosis of RA patients. The combination of the two biomarkers in conjunction with other clinical measures is an important tool for the diagnosis and management of RA patients. PMID:21915375

Proximity Effects of Beryllium-Doped GaN Buffer Layers on the Electronic Properties of Epitaxial AlGaN/GaN Heterostructures

DTIC Science & Technology

2010-05-17

arranged by Prof. A. Zaslavsky Keywords: Gallium nitride High electron mobility transistor Molecular beam epitaxy Homoepitaxy Doping a b s t r a c t AlGaN...GaN/Be:GaN heterostructures have been grown by rf-plasma molecular beam epitaxy on free- standing semi-insulating GaN substrates, employing...hydride vapor phase epitaxy (HVPE) grown GaN sub- strates has enabled the growth by molecular beam epitaxy (MBE) of AlGaN/GaNHEMTswith significantly

Standing Vs Supine; Does it Matter in Cough Stress Testing?

PubMed

Patnam, Radhika; Edenfield, Autumn L; Swift, Steven E

The aim of this study was to compare the sensitivity of cough stress test in the standing versus supine position in the evaluation of incontinent females. We performed a prospective observational study of women with the chief complaint of urinary incontinence (UI) undergoing a provocative cough stress test (CST). Subjects underwent both a standing and a supine CST. Testing order was randomized via block randomization. Cough stress test was performed in a standard method via backfill of 200 mL or until the subject described strong urge. The subjects were asked to cough, and the physician documented urine leakage by direct observation. The gold standard for stress UI diagnosis was a positive CST in either position. Sixty subjects were enrolled, 38 (63%) tested positive on any CST, with 38 (63%) positive on standing compared with 29 (28%) positive on supine testing. Nine women (15%) had positive standing and negative supine testing. No subjects had negative standing with positive supine testing. There were no significant differences in positive tests between the 2 randomized groups (standing first and supine second vs. supine first and standing second). When compared with the gold standard of any positive provocative stress test, the supine CST has a sensitivity of 76%, whereas the standing CST has a sensitivity of 100%. The standing CST is more sensitive than the supine CST and should be performed in any patient with a complaint of UI and negative supine CST. The order of testing either supine or standing first does not affect the results.

Dual optimization method of radiofrequency and quasistatic field simulations for reduction of eddy currents generated on 7T radiofrequency coil shielding.

PubMed

Zhao, Yujuan; Zhao, Tiejun; Raval, Shailesh B; Krishnamurthy, Narayanan; Zheng, Hai; Harris, Chad T; Handler, William B; Chronik, Blaine A; Ibrahim, Tamer S

2015-11-01

To optimize the design of radiofrequency (RF) shielding of transmit coils at 7T and reduce eddy currents generated on the RF shielding when imaging with rapid gradient waveforms. One set of a four-element, 2 × 2 Tic-Tac-Toe head coil structure was selected and constructed to study eddy currents on the RF coil shielding. The generated eddy currents were quantitatively studied in the time and frequency domains. The RF characteristics were studied using the finite difference time domain method. Five different kinds of RF shielding were tested on a 7T MRI scanner with phantoms and in vivo human subjects. The eddy current simulation method was verified by the measurement results. Eddy currents induced by solid/intact and simple-structured slotted RF shielding significantly distorted the gradient fields. Echo-planar images, B1+ maps, and S matrix measurements verified that the proposed slot pattern suppressed the eddy currents while maintaining the RF characteristics of the transmit coil. The presented dual-optimization method could be used to design RF shielding and reduce the gradient field-induced eddy currents while maintaining the RF characteristics of the transmit coil. © 2014 Wiley Periodicals, Inc.

RF Testing Of Microwave Integrated Circuits

NASA Technical Reports Server (NTRS)

Romanofsky, R. R.; Ponchak, G. E.; Shalkhauser, K. A.; Bhasin, K. B.

1988-01-01

Fixtures and techniques are undergoing development. Four test fixtures and two advanced techniques developed in continuing efforts to improve RF characterization of MMIC's. Finline/waveguide test fixture developed to test submodules of 30-GHz monolithic receiver. Universal commercially-manufactured coaxial test fixture modified to enable characterization of various microwave solid-state devices in frequency range of 26.5 to 40 GHz. Probe/waveguide fixture is compact, simple, and designed for non destructive testing of large number of MMIC's. Nondestructive-testing fixture includes cosine-tapered ridge, to match impedance wavequide to microstrip. Advanced technique is microwave-wafer probing. Second advanced technique is electro-optical sampling.

A-3 Test Stand work

NASA Image and Video Library

2011-07-29

Work continues on the A-3 Test Stand at Stennis Space Center. The new stand will allow operators to test next-generation rocket engines at simulated altitudes up to 100,000 feet. The test stand is scheduled for completion and activation in 2013.

A-3 Test Stand construction

NASA Image and Video Library

2010-10-01

An 80,000-gallon liquid hydrogen tank is placed at the A-3 Test Stand construction site on Sept. 24, 2010. The tank will provide propellant for tests of next-generation rocket engines at the stand. It will be placed upright on top of the stand, helping to increase the overall height to 300 feet. Once completed, the A-3 Test Stand will enable operators to test rocket engines at simulated altitudes of up to 100,000 feet. The A-3 stand is the first large rocket engine test structure to be built at Stennis Space Center since the 1960s.

A-3 Test Stand construction

NASA Image and Video Library

2010-09-24

A 35,000-gallon liquid oxygen tank is placed at the A-3 Test Stand construction site on Sept. 24, 2010. The tank will provide propellant for tests of next-generation rocket engines at the stand. It will be placed upright on top of the stand, helping to increase the overall height to 300 feet. Once completed, the A-3 Test Stand will enable operators to test rocket engines at simulated altitudes of up to 100,000 feet. The A-3 stand is the first large rocket engine test structure to be built at Stennis Space Center since the 1960s.

Retrospective analysis of RF heating measurements of passive medical implants.

PubMed

Song, Ting; Xu, Zhiheng; Iacono, Maria Ida; Angelone, Leonardo M; Rajan, Sunder

2018-05-09

The test reports for the RF-induced heating of metallic devices of hundreds of medical implants have been provided to the U.S. Food and Drug Administration as a part of premarket submissions. The main purpose of this study is to perform a retrospective analysis of the RF-induced heating data provided in the reports to analyze the trends and correlate them with implant geometric characteristics. The ASTM-based RF heating test reports from 86 premarket U.S. Food and Drug Administration submissions were reviewed by three U.S. Food and Drug Administration reviewers. From each test report, the dimensions and RF-induced heating values for a given whole-body (WB) specific absorption rate (SAR) and local background (LB) SAR were extracted and analyzed. The data from 56 stents were analyzed as a subset to further understand heating trends and length dependence. For a given WB SAR, the LB/WB SAR ratio varied significantly across the test labs, from 2.3 to 11.3. There was an increasing trend on the temperature change per LB SAR with device length. The maximum heating for stents occurred at lengths of approximately 100 mm at 3 T, and beyond 150 mm at 1.5 T. Differences in the LB/WB SAR ratios across testing labs and various MRI scanners could lead to inconsistent WB SAR labeling. Magnetic resonance (MR) conditional labeling based on WB SAR should be derived from a conservative estimate of global LB/WB ratios. Published 2018. This article is a U.S. Government work and is in the public domain in the USA.

Photographic copy of site plan for proposed Test Stand "D" ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Photographic copy of site plan for proposed Test Stand "D" in 1958. The contemporary site plans of test stands "A," "B," and "C" are also visible, along with the interconnecting tunnel system. California Institute of Technology, Jet Propulsion Laboratory, Plant Engineering "Site Plan for Proposed Test Stand "D" - Edwards Test Station," drawing no. ESP/22-0, 14 November 1958 - Jet Propulsion Laboratory Edwards Facility, Test Stand D, Edwards Air Force Base, Boron, Kern County, CA

A-3 Test Stand continues with test cell installation

NASA Image and Video Library

2010-07-20

Employees at Stennis Space Center continue work on the A-3 Test Stand. As shown, a section of the test cell is lifted for installation on the stand's structural steel frame. Work on the A-3 Test Stand began in 2007. It is scheduled for activation in 2012.

RF conditioning and beam experiments on 400 keV RFQ accelerator at BARC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gupta, Shrikrishna; Rao, S.V.L.S.; Kumar, Rajesh, E-mail: sgupta@barc.gov.in

2014-07-01

A 400 keV Radio-frequency quadrupole accelerator (RFQ) has been designed, developed and tested at BARC. This will be used as a neutron generator (via D-T reaction). The RFQ operates at a resonant frequency of 350 MHz and needs an RF power of ∼ 60 kW to accelerate the deuteron beam to 400 keV within a length of 1.03 m. Though the RFQ is designed for deuteron beam, it was tested by accelerating both the proton and deuteron beams to their designed values of 200 and 400 keV respectively. The proton and deuteron beam experiments required peak RF power of approx.more » 15 kW and 60 kW respectively at 350 MHz. The RF power from the tetrode amplifier and coaxial transmission lines is coupled to the cavity by a coaxial loop coupler. As the coupler and cavity operated at vacuum of better than 2e-6 torr, extensive RF conditioning of the cavity and coupler was performed to reach at the desired power levels. (author)« less

High power tests of an electroforming cavity operating at 11.424 GHz

NASA Astrophysics Data System (ADS)

Dolgashev, V. A.; Gatti, G.; Higashi, Y.; Leonardi, O.; Lewandowski, J. R.; Marcelli, A.; Rosenzweig, J.; Spataro, B.; Tantawi, S. G.; Yeremian, D. A.

2016-03-01

The achievement of ultra high accelerating gradients is mandatory in order to fabricate compact accelerators at 11.424 GHz for scientific and industrial applications. An extensive experimental and theoretical program to determine a reliable ultra high gradient operation of the future linear accelerators is under way in many laboratories. In particular, systematic studies on the 11.424 GHz frequency accelerator structures, R&D on new materials and the associated microwave technology are in progress to achieve accelerating gradients well above 120 MeV/m. Among the many, the electroforming procedure is a promising approach to manufacture high performance RF devices in order to avoid the high temperature brazing and to produce precise RF structures. We report here the characterization of a hard high gradient RF accelerating structure at 11.424 GHz fabricated using the electroforming technique. Low-level RF measurements and high power RF tests carried out at the SLAC National Accelerator Laboratory on this prototype are presented and discussed. In addition, we present also a possible layout where the water-cooling of irises based on the electroforming process has been considered for the first time.

Operation of large RF sources for H-: Lessons learned at ELISE

NASA Astrophysics Data System (ADS)

Fantz, U.; Wünderlich, D.; Heinemann, B.; Kraus, W.; Riedl, R.

2017-08-01

The goal of the ELISE test facility is to demonstrate that large RF-driven negative ion sources (1 × 1 m2 source area with 360 kW installed RF power) can achieve the parameters required for the ITER beam sources in terms of current densities and beam homogeneity at a filling pressure of 0.3 Pa for pulse lengths of up to one hour. With the experience in operation of the test facility, the beam source inspection and maintenance as well as with the results of the achieved source performance so far, conclusions are drawn for commissioning and operation of the ITER beam sources. Addressed are critical technical RF issues, extrapolations to the required RF power, Cs consumption and Cs ovens, the need of adjusting the magnetic filter field strength as well as the temporal dynamic and spatial asymmetry of the co-extracted electron current. It is proposed to relax the low pressure limit to 0.4 Pa and to replace the fixed electron-to-ion ratio by a power density limit for the extraction grid. This would be highly beneficial for controlling the co-extracted electrons.

Computational Investigation of Helical Traveling Wave Tube Transverse RF Field Forces

NASA Technical Reports Server (NTRS)

Kory, Carol L.; Dayton, James A.

1998-01-01

In a previous study using a fully three-dimensional (3D) helical slow-wave circuit cold- test model it was found, contrary to classical helical circuit analyses, that transverse FF electric fields have significant amplitudes compared with the longitudinal component. The RF fields obtained using this helical cold-test model have been scaled to correspond to those of an actual TWT. At the output of the tube, RF field forces reach 61%, 26% and 132% for radial, azimuthal and longitudinal components, respectively, compared to radial space charge forces indicating the importance of considering them in the design of electron beam focusing.

Characterizing stand-level forest canopy cover and height using Landsat time series, samples of airborne LiDAR, and the Random Forest algorithm

NASA Astrophysics Data System (ADS)

Ahmed, Oumer S.; Franklin, Steven E.; Wulder, Michael A.; White, Joanne C.

2015-03-01

Many forest management activities, including the development of forest inventories, require spatially detailed forest canopy cover and height data. Among the various remote sensing technologies, LiDAR (Light Detection and Ranging) offers the most accurate and consistent means for obtaining reliable canopy structure measurements. A potential solution to reduce the cost of LiDAR data, is to integrate transects (samples) of LiDAR data with frequently acquired and spatially comprehensive optical remotely sensed data. Although multiple regression is commonly used for such modeling, often it does not fully capture the complex relationships between forest structure variables. This study investigates the potential of Random Forest (RF), a machine learning technique, to estimate LiDAR measured canopy structure using a time series of Landsat imagery. The study is implemented over a 2600 ha area of industrially managed coastal temperate forests on Vancouver Island, British Columbia, Canada. We implemented a trajectory-based approach to time series analysis that generates time since disturbance (TSD) and disturbance intensity information for each pixel and we used this information to stratify the forest land base into two strata: mature forests and young forests. Canopy cover and height for three forest classes (i.e. mature, young and mature and young (combined)) were modeled separately using multiple regression and Random Forest (RF) techniques. For all forest classes, the RF models provided improved estimates relative to the multiple regression models. The lowest validation error was obtained for the mature forest strata in a RF model (R2 = 0.88, RMSE = 2.39 m and bias = -0.16 for canopy height; R2 = 0.72, RMSE = 0.068% and bias = -0.0049 for canopy cover). This study demonstrates the value of using disturbance and successional history to inform estimates of canopy structure and obtain improved estimates of forest canopy cover and height using the RF algorithm.

Optically controlled switch-mode current-source amplifiers for on-coil implementation in high field parallel transmission

PubMed Central

Gudino, Natalia; Duan, Qi; de Zwart, Jacco A; Murphy-Boesch, Joe; Dodd, Stephen J; Merkle, Hellmut; van Gelderen, Peter; Duyn, Jeff H

2015-01-01

Purpose We tested the feasibility of implementing parallel transmission (pTX) for high field MRI using a radiofrequency (RF) amplifier design to be located on or in the immediate vicinity of a RF transmit coil. Method We designed a current-source switch-mode amplifier based on miniaturized, non-magnetic electronics. Optical RF carrier and envelope signals to control the amplifier were derived, through a custom-built interface, from the RF source accessible in the scanner control. Amplifier performance was tested by benchtop measurements as well as with imaging at 7 T (300 MHz) and 11.7 T (500 MHz). The ability to perform pTX was evaluated by measuring inter-channel coupling and phase adjustment in a 2-channel setup. Results The amplifier delivered in excess of 44 W RF power and caused minimal interference with MRI. The interface derived accurate optical control signals with carrier frequencies ranging from 64 to 750 MHz. Decoupling better than 14 dB was obtained between 2 coil loops separated by only 1 cm. Application to MRI was demonstrated by acquiring artifact-free images at 7 T and 11.7 T. Conclusion An optically controlled miniaturized RF amplifier for on-coil implementation at high field is demonstrated that should facilitate implementation of high-density pTX arrays. PMID:26256671

Monte-Carlo Orbit/Full Wave Simulation of Fast Alfvén Wave (FW) Damping on Resonant Ions in Tokamaks

NASA Astrophysics Data System (ADS)

Choi, M.; Chan, V. S.; Tang, V.; Bonoli, P.; Pinsker, R. I.; Wright, J.

2005-09-01

To simulate the resonant interaction of fast Alfvén wave (FW) heating and Coulomb collisions on energetic ions, including finite orbit effects, a Monte-Carlo code ORBIT-RF has been coupled with a 2D full wave code TORIC4. ORBIT-RF solves Hamiltonian guiding center drift equations to follow trajectories of test ions in 2D axisymmetric numerical magnetic equilibrium under Coulomb collisions and ion cyclotron radio frequency quasi-linear heating. Monte-Carlo operators for pitch-angle scattering and drag calculate the changes of test ions in velocity and pitch angle due to Coulomb collisions. A rf-induced random walk model describing fast ion stochastic interaction with FW reproduces quasi-linear diffusion in velocity space. FW fields and its wave numbers from TORIC are passed on to ORBIT-RF to calculate perpendicular rf kicks of resonant ions valid for arbitrary cyclotron harmonics. ORBIT-RF coupled with TORIC using a single dominant toroidal and poloidal wave number has demonstrated consistency of simulations with recent DIII-D FW experimental results for interaction between injected neutral-beam ions and FW, including measured neutron enhancement and enhanced high energy tail. Comparison with C-Mod fundamental heating discharges also yielded reasonable agreement.

Laboratory-scale uranium RF plasma confinement experiments

NASA Technical Reports Server (NTRS)

Roman, W. C.

1976-01-01

An experimental investigation was conducted using 80 kW and 1.2 MW RF induction heater facilities to aid in developing the technology necessary for designing a self-critical fissioning uranium plasma core reactor. Pure uranium hexafluoride (UF6) was injected into argon-confined, steady-state, RF-heated plasmas in different uranium plasma confinement tests to investigate the characteristics of plamas core nuclear reactors. The objectives were: (1) to confine as high a density of uranium vapor as possible within the plasma while simultaneously minimizing the uranium compound wall deposition; (2) to develop and test materials and handling techniques suitable for use with high-temperature, high-pressure gaseous UF6; and (3) to develop complementary diagnostic instrumentation and measurement techniques to characterize the uranium plasma and residue deposited on the test chamber components. In all tests, the plasma was a fluid-mechanically-confined vortex-type contained within a fused-silica cylindrical test chamber. The test chamber peripheral wall was 5.7 cm ID by 10 cm long.

A-3 Test Stand

NASA Image and Video Library

2012-06-08

A tethered Stennis Space Center employee climbs an A-3 Test Stand ladder June 8, 2012, against the backdrop of the A-2 and B-1/B-2 stands. The new A-3 Test Stand will enable simulated high-altitude testing of next-generation rocket engines.

A-3 Test Stand

NASA Image and Video Library

2012-06-08

A tethered Stennis Space Center employee climbs an A-3 Test Stand ladded June 8, 2012, against the backdrop of the A-2 and B-1/B-2 stands. The new A-3 Test Stand will enable simulated high-altitude testing of next-generation rocket engines.

Study of Electron Swarm in High Pressure Hydrogen Gas Filled RF Cavities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yonehara, K.; Chung, M.; Jansson, A.

2010-05-01

A high pressure hydrogen gas filled RF cavity has been proposed for use in the muon collection system for a muon collider. It allows for high electric field gradients in RF cavities located in strong magnetic fields, a condition frequently encountered in a muon cooling channel. In addition, an intense muon beam will generate an electron swarm via the ionization process in the cavity. A large amount of RF power will be consumed into the swarm. We show the results from our studies of the HV RF breakdown in a cavity without a beam and present some results on themore » resulting electron swarm dynamics. This is preliminary to actual beam tests which will take place late in 2010.« less

Initial Thrust Measurements of Marshall's Ion-ioN Thruster

NASA Technical Reports Server (NTRS)

Caruso, Natalie R. S.; Scogin, Tyler; Liu, Thomas M.; Walker, Mitchell L. R.; Polzin, Kurt A.; Dankanich, John W.

2015-01-01

Electronegative ion thrusters are a variation of traditional gridded ion thruster technology differentiated by the production and acceleration of both positive and negative ions. Benefits of electronegative ion thrusters include the elimination of lifetime-limiting cathodes from the thruster architecture and the ability to generate appreciable thrust from both charge species. While much progress has been made in the development of electronegative ion thruster technology, direct thrust measurements are required to unambiguously demonstrate the efficacy of the concept and support continued development. In the present work, direct thrust measurements of the thrust produced by the MINT (Marshall's Ion-ioN Thruster) are performed using an inverted-pendulum thrust stand in the High-Power Electric Propulsion Laboratory's Vacuum Test Facility-1 at the Georgia Institute of Technology with operating pressures ranging from 4.8 x 10(exp -5) and 5.7 x 10(exp -5) torr. Thrust is recorded while operating with a propellant volumetric mixture ratio of 5:1 argon to nitrogen with total volumetric flow rates of 6, 12, and 24 sccm (0.17, 0.34, and 0.68 mg/s). Plasma is generated using a helical antenna at 13.56 MHz and radio frequency (RF) power levels of 150 and 350 W. The acceleration grid assembly is operated using both sinusoidal and square waveform biases of +/-350 V at frequencies of 4, 10, 25, 125, and 225 kHz. Thrust is recorded for two separate thruster configurations: with and without the magnetic filter. No thrust is discernable during thruster operation without the magnetic filter for any volumetric flow rate, RF forward Power level, or acceleration grid biasing scheme. For the full thruster configuration, with the magnetic filter installed, a brief burst of thrust of approximately 3.75 mN +/- 3 mN of error is observed at the start of grid operation for a volumetric flow rate of 24 sccm at 350 W RF power using a sinusoidal waveform grid bias at 125 kHz and +/- 350 V. Similar bursts in thrust are observed using a square waveform grid bias at 10 kHz and +/- 350 V for volumetric flow rates of 6, 10, and 12 sccm at 150, 350, and 350 W respectively. The only operating condition that exhibits repeated thrust spikes throughout thruster operation is the 24 sccm condition with a 5:1 mixture ratio at 150 W RF power using the 10 kHz square waveform acceleration grid bias. Thrust spikes for this condition measure 3 mN with an error of +/- 2.5 mN. There are no operating conditions tested that show continuous thrust production.

Design and RF measurements of a 5 GHz 500 kW window for the ITER LHCD system

NASA Astrophysics Data System (ADS)

Hillairet, J.; Achard, J.; Bae, Y. S.; Bernard, J. M.; Dechambre, N.; Delpech, L.; Ekedahl, A.; Faure, N.; Goniche, M.; Kim, J.; Larroque, S.; Magne, R.; Marfisi, L.; Namkung, W.; Park, H.; Park, S.; Poli, S.; Vulliez, K.

2014-02-01

CEA/IRFM is conducting R&D efforts in order to validate the critical RF components of the 5 GHz ITER LHCD system, which is expected to transmit 20 MW of RF power to the plasma. Two 5 GHz 500 kW BeO pill-box type window prototypes have been manufactured in 2012 by the PMB Company, in close collaboration with CEA/IRFM. Both windows have been validated at low power, showing good agreement between measured and modeling, with a return loss better than 32 dB and an insertion loss below 0.05 dB. This paper reports on the window RF design and the low power measurements. The high power tests up to 500kW have been carried out in March 2013 in collaboration with NFRI. Results of these tests are also reported.

Uses and Misuses of Ted Kaczynski's MMPI.

PubMed

Ben-Porath, Yossef S

2018-05-22

Although case studies can be a helpful didactic aid when teaching personality assessment and illustrating use of a test, they can, of course, not be used as "evidence" that a test "works" or does not work. This article, however, reviews and discusses the far more problematic uses instantiated in a case study of Ted Kaczynski's Minnesota Multiphasic Personality Inventory (MMPI). A series of errors of omission and commission are identified in Butcher, Hass, Greene, and Nelson's ( 2015 ) effort to criticize the MMPI-2-RF. These include not disclosing that Butcher's interpretive Minnesota Report for Forensic Settings indicates that the protocol is invalid, not including most of the MMPI-2 and MMPI-2-RF scores that contradict the authors' assertions, and mischaracterizing the MMPI-2-RF findings. Proper use of a case study is then illustrated by a discussion of diagnostic considerations indicated by the MMPI-2-RF findings.

Integrating support vector machines and random forests to classify crops in time series of Worldview-2 images

NASA Astrophysics Data System (ADS)

Zafari, A.; Zurita-Milla, R.; Izquierdo-Verdiguier, E.

2017-10-01

Crop maps are essential inputs for the agricultural planning done at various governmental and agribusinesses agencies. Remote sensing offers timely and costs efficient technologies to identify and map crop types over large areas. Among the plethora of classification methods, Support Vector Machine (SVM) and Random Forest (RF) are widely used because of their proven performance. In this work, we study the synergic use of both methods by introducing a random forest kernel (RFK) in an SVM classifier. A time series of multispectral WorldView-2 images acquired over Mali (West Africa) in 2014 was used to develop our case study. Ground truth containing five common crop classes (cotton, maize, millet, peanut, and sorghum) were collected at 45 farms and used to train and test the classifiers. An SVM with the standard Radial Basis Function (RBF) kernel, a RF, and an SVM-RFK were trained and tested over 10 random training and test subsets generated from the ground data. Results show that the newly proposed SVM-RFK classifier can compete with both RF and SVM-RBF. The overall accuracies based on the spectral bands only are of 83, 82 and 83% respectively. Adding vegetation indices to the analysis result in the classification accuracy of 82, 81 and 84% for SVM-RFK, RF, and SVM-RBF respectively. Overall, it can be observed that the newly tested RFK can compete with SVM-RBF and RF classifiers in terms of classification accuracy.

13. Photographic copy of site plan displaying Test Stand 'C' ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

13. Photographic copy of site plan displaying Test Stand 'C' (4217/E-18), Test Stand 'D' (4223/E-24), and Control and Recording Center (4221/E-22) with ancillary structures, and connecting roads and services. California Institute of Technology, Jet Propulsion Laboratory, Facilities Engineering and Construction Office 'Repairs to Test Stand 'C,' Edwards Test Station, Legend & Site Plan M-1,' drawing no. ESP/115, August 14, 1987. - Jet Propulsion Laboratory Edwards Facility, Test Stand C, Edwards Air Force Base, Boron, Kern County, CA

Credit WCT. Photographic copy of photograph, view of Test Stand ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Credit WCT. Photographic copy of photograph, view of Test Stand "D" from Test Stand "A" while a rocket engine test is in progress. Cloud of steam is from partly from water created by propellant reaction and from water sprayed by flame bucket into engine exhaust for cooling purposes. A portion of Test Stand "C" is visible at the far right. (JPL negative no. 384-2082-B, 23 October 1959) - Jet Propulsion Laboratory Edwards Facility, Test Stand D, Edwards Air Force Base, Boron, Kern County, CA

Credit BG. View looking northeast at southwestern side of Test ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Credit BG. View looking northeast at southwestern side of Test Stand "D" complex. Test Stand "D" workshop (Building 4222/E-23) is at left; shed to its immediate right is an entrance to underground tunnel system which interconnects all test stands. To the right of Test Stand "D" tower are four Clayton water-tube flash boilers once used in the Steam Generator Plant 4280/E-81 to power the vacuum ejector system at "D" and "C" stands. A corner of 4280/E-81 appears behind the boilers. Boilers were removed as part of stand dismantling program. The Dv (vertical vacuum) Test Cell is located in the Test Stand "D" tower, behind the sunscreen on the west side. The top of the tower contains a hoist for lifting or lowering rocket engines into the Dv Cell. Other equipment mounted in the tower is part of the steam-driven vacuum ejector system - Jet Propulsion Laboratory Edwards Facility, Test Stand D, Edwards Air Force Base, Boron, Kern County, CA

Performance of machine-learning scoring functions in structure-based virtual screening

PubMed Central

Wójcikowski, Maciej; Ballester, Pedro J.; Siedlecki, Pawel

2017-01-01

Classical scoring functions have reached a plateau in their performance in virtual screening and binding affinity prediction. Recently, machine-learning scoring functions trained on protein-ligand complexes have shown great promise in small tailored studies. They have also raised controversy, specifically concerning model overfitting and applicability to novel targets. Here we provide a new ready-to-use scoring function (RF-Score-VS) trained on 15 426 active and 893 897 inactive molecules docked to a set of 102 targets. We use the full DUD-E data sets along with three docking tools, five classical and three machine-learning scoring functions for model building and performance assessment. Our results show RF-Score-VS can substantially improve virtual screening performance: RF-Score-VS top 1% provides 55.6% hit rate, whereas that of Vina only 16.2% (for smaller percent the difference is even more encouraging: RF-Score-VS top 0.1% achieves 88.6% hit rate for 27.5% using Vina). In addition, RF-Score-VS provides much better prediction of measured binding affinity than Vina (Pearson correlation of 0.56 and −0.18, respectively). Lastly, we test RF-Score-VS on an independent test set from the DEKOIS benchmark and observed comparable results. We provide full data sets to facilitate further research in this area (http://github.com/oddt/rfscorevs) as well as ready-to-use RF-Score-VS (http://github.com/oddt/rfscorevs_binary). PMID:28440302

1. Photographic copy of original engineering drawing for Test Stand ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. Photographic copy of original engineering drawing for Test Stand 'C.' California Institute of Technology, Jet Propulsion Laboratory, Plant Engineering 'New Test Stand Plan -- Edwards Test Station' drawing no. E18/2-3, 18 January 1957. - Jet Propulsion Laboratory Edwards Facility, Test Stand C, Edwards Air Force Base, Boron, Kern County, CA

Development of RF plasma simulations of in-reactor tests of small models of the nuclear light bulb fuel region

NASA Technical Reports Server (NTRS)

Roman, W. C.; Jaminet, J. F.

1972-01-01

Experiments were conducted to develop test configurations and technology necessary to simulate the thermal environment and fuel region expected to exist in in-reactor tests of small models of nuclear light bulb configurations. Particular emphasis was directed at rf plasma tests of approximately full-scale models of an in-reactor cell suitable for tests in Los Alamos Scientific Laboratory's Nuclear Furnace. The in-reactor tests will involve vortex-stabilized fissioning uranium plasmas of approximately 200-kW power, 500-atm pressure and equivalent black-body radiating temperatures between 3220 and 3510 K.

Dual-mode capability for hardware-in-the-loop

NASA Astrophysics Data System (ADS)

Vamivakas, A. N.; Jackson, Ron L.

2000-07-01

This paper details a Hardware-in-the-Loop Facility (HIL) developed for evaluation and verification of a missile system with dual mode capability. The missile has the capability of tracking and intercepting a target using either an RF antenna or an IR sensor. The testing of a dual mode system presents a significant challenge in the development of the HIL facility. An IR and RF target environment must be presented simultaneously to the missile under test. These targets, simulated by IR and RF sources, must be presented to the missile under test without interference from each other. The location of each source is critical in the development of the HIL facility. The requirements for building a HIL facility with dual mode capability and the methodology for testing the dual mode system are defined within this paper. Methods for the verification and validation of the facility are discussed.

View looking west at Test Stand 'A' complex in morning ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

View looking west at Test Stand 'A' complex in morning sun. View shows Monitor Building 4203/E-4 at left, barrier (Building 4216/E-17) to right of 4203/E-4, and Test Stand 'A' tower. Attached structure to lower left of tower is Test Stand 'A' machine room which contained refrigeration equipment. Building in right background with Test Stand 'A' tower shadow on it is Assembly Building 4288/E-89, built in 1984. Row of ground-mounted brackets in foreground was used to carry electrical cable and/or fuel lines. - Jet Propulsion Laboratory Edwards Facility, Test Stand A, Edwards Air Force Base, Boron, Kern County, CA

Whole body exposure to 2.4 GHz WIFI signals: effects on cognitive impairment in adult triple transgenic mouse models of Alzheimer's disease (3xTg-AD).

PubMed

Banaceur, Sana; Banasr, Sihem; Sakly, Mohsen; Abdelmelek, Hafedh

2013-03-01

The present investigation aimed at evaluating the effects of long-term exposure to WIFI type radiofrequency (RF) signals (2.40 GHz), two hours per day during one month at a Specific Absorption Rate (SAR) of 1.60 W/kg. The effects of RF exposure were studied on wildtype mice and triple transgenic mice (3xTg-AD) destined to develop Alzheimer's-like cognitive impairment. Mice were divided into four groups: two sham groups (WT, TG; n=7) and two exposed groups (WTS, TGS; n=7). The cognitive interference task used in this study was designed from an analogous human cognitive interference task including the Flex field activity system test, the two-compartment box test and the Barnes maze test. Our data demonstrate for the first time that RF improves cognitive behavior of 3xTg-AD mice. We conclude that RF exposure may represent an effective memory-enhancing approach in Alzheimer's disease. Copyright © 2012 Elsevier B.V. All rights reserved.

Expanding Hardware-in-the-Loop Formation Navigation and Control with Radio Frequency Crosslink Ranging

NASA Technical Reports Server (NTRS)

Mitchell, Jason W.; Barbee, Brent W.; Baldwin, Philip J.; Luquette, Richard J.

2007-01-01

The Formation Flying Testbed (FFTB) at the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) provides a hardware-in-the-loop test environment for formation navigation and control. The facility continues to evolve as a modular, hybrid, dynamic simulation facility for end-to-end guidance, navigation, and control (GN&C) design and analysis of formation flying spacecraft. The core capabilities of the FFTB, as a platform for testing critical hardware and software algorithms in-the-loop, are reviewed with a focus on recent improvements. With the most recent improvement, in support of Technology Readiness Level (TRL) 6 testing of the Inter-spacecraft Ranging and Alarm System (IRAS) for the Magnetospheric Multiscale (MMS) mission, the FFTB has significantly expanded its ability to perform realistic simulations that require Radio Frequency (RF) ranging sensors for relative navigation with the Path Emulator for RF Signals (PERFS). The PERFS, currently under development at NASA GSFC, modulates RF signals exchanged between spacecraft. The RF signals are modified to accurately reflect the dynamic environment through which they travel, including the effects of medium, moving platforms, and radiated power.

Dielectric Heaters for Testing Spacecraft Nuclear Reactors

NASA Technical Reports Server (NTRS)

Sims, William Herbert; Bitteker, Leo; Godfroy, Thomas

2006-01-01

A document proposes the development of radio-frequency-(RF)-driven dielectric heaters for non-nuclear thermal testing of the cores of nuclear-fission reactors for spacecraft. Like the electrical-resistance heaters used heretofore for such testing, the dielectric heaters would be inserted in the reactors in place of nuclear fuel rods. A typical heater according to the proposal would consist of a rod of lossy dielectric material sized and shaped like a fuel rod and containing an electrically conductive rod along its center line. Exploiting the dielectric loss mechanism that is usually considered a nuisance in other applications, an RF signal, typically at a frequency .50 MHz and an amplitude between 2 and 5 kV, would be applied to the central conductor to heat the dielectric material. The main advantage of the proposal is that the wiring needed for the RF dielectric heating would be simpler and easier to fabricate than is the wiring needed for resistance heating. In some applications, it might be possible to eliminate all heater wiring and, instead, beam the RF heating power into the dielectric rods from external antennas.

25. "TEST STAND 1A UTILIZED TO TEST THE ATLAS ICBM", ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

25. "TEST STAND 1-A UTILIZED TO TEST THE ATLAS ICBM", CROPPED OUT: "DIRECTORATE OF MISSILE CAPTIVE TEST, EDWARDS AFB." Photo no. 11,371 57; G-AFFTC 15 OCT 57. Looking southwest from below the stand. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-A, Test Area 1-120, north end of Jupiter Boulevard, Boron, Kern County, CA

n/a

NASA Image and Video Library

1963-01-15

At its founding, the Marshall Space Flight Center (MSFC) inherited the Army’s Jupiter and Redstone test stands, but much larger facilities were needed for the giant stages of the Saturn V. From 1960 to 1964, the existing stands were remodeled and a sizable new test area was developed. The new comprehensive test complex for propulsion and structural dynamics was unique within the nation and the free world, and they remain so today because they were constructed with foresight to meet the future as well as on going needs. Construction of the S-IC Static test stand complex began in 1961 in the west test area of MSFC, and was completed in 1964. The S-IC static test stand was designed to develop and test the 138-ft long and 33-ft diameter Saturn V S-IC first stage, or booster stage, weighing in at 280,000 pounds. Required to hold down the brute force of a 7,500,000-pound thrust produced by 5 F-1 engines, the S-IC static test stand was designed and constructed with the strength of hundreds of tons of steel and 12,000,000 pounds of cement, planted down to bedrock 40 feet below ground level. The foundation walls, constructed with concrete and steel, are 4 feet thick. The base structure consists of four towers with 40-foot-thick walls extending upward 144 feet above ground level. The structure was topped by a crane with a 135-foot boom. With the boom in the upright position, the stand was given an overall height of 405 feet, placing it among the highest structures in Alabama at the time. In addition to the stand itself, related facilities were constructed during this time. Built directly east of the test stand was the Block House, which served as the control center for the test stand. The two were connected by a narrow access tunnel which housed the cables for the controls. The F-1 Engine test stand was built north of the massive S-IC test stand. The F-1 test stand is a vertical engine firing test stand, 239 feet in elevation and 4,600 square feet in area at the base, and was designed to assist in the development of the F-1 Engine. Capability is provided for static firing of 1.5 million pounds of thrust using liquid oxygen and kerosene. Like the S-IC stand, the foundation of the F-1 stand is keyed into the bedrock approximately 40 feet below grade. This aerial photograph, taken January 15, 1963, gives a close overall view of the newly developed test complex. Depicted in the forefront center is the S-IC test stand with towers prominent, the Block House is seen in the center just above the S-IC test stand, and the large hole to the left, located midway between the two is the F-1 test stand site.

Concomitant Effects of Ramadan Fasting and Time-Of-Day on Apolipoprotein AI, B, Lp-a and Homocysteine Responses during Aerobic Exercise in Tunisian Soccer Players

PubMed Central

Hammouda, Omar; Chtourou, Hamdi; Aloui, Asma; Chahed, Henda; Kallel, Choumous; Miled, Abdelhedi; Chamari, Karim; Chaouachi, Anis; Souissi, Nizar

2013-01-01

Objective To examine the time-of-day and Ramadan fasting (RF) effects on serum apolipoprotein-AI (Apo-AI) and B (Apo-B), lipoprotein particles-a (Lp-a), high-sensitive C-reactive-protein (hs-CRP), and homocysteine (Hcy) during the Yo-Yo intermittent recovery test (YYIRT). Design Performance and biochemical measures were completed at two times-of-day (07:00 and 17:00 h), 1-week before RF (BR), the second week of RF (SWR), and the fourth week of RF (ER). Setting For each session, subjects performed the YYIRT, and blood samples were taken before and 3-min after the test for biochemical measures. Participants Fifteen soccer players. Main Outcome Measures Total distance during the YYIRT, core temperature, body composition, dietary intakes, lipid (HDL-C, LDL-C, Apo-AI, B and Lp-a) and inflammatory (hs-CRP and Hcy) profiles. Results Performances during the YYIRT were higher in the evening than the morning BR (P < 0.05), but this fluctuation was not observed during RF. Moreover, LDL-C, ApoB, and Lp-a were stable throughout the daytime BR. However, during RF, they decreased at 17:00 h (P < 0.05). Likewise, HDL-C and Apo-AI increased after the exercise and were higher at 17:00 h BR (P < 0.001). Moreover, these parameters increased during RF (P < 0.01). Furthermore, Hcy and hs-CRP increased during the exercise (P < 0.01) with higher evening levels BR. During ER, the diurnal pattern of Hcy was inversed (P < 0.001). Conclusions This study concluded that caloric restriction induced by RF seems to ameliorate lipid and inflammatory markers of cardiovascular health during intermittent exercise performed in the evening. PMID:24244572

Mobile phone base station radiation does not affect neoplastic transformation in BALB/3T3 cells.

PubMed

Hirose, H; Suhara, T; Kaji, N; Sakuma, N; Sekijima, M; Nojima, T; Miyakoshi, J

2008-01-01

A large-scale in vitro study focusing on low-level radiofrequency (RF) fields from mobile radio base stations employing the International Mobile Telecommunication 2000 (IMT-2000) cellular system was conducted to test the hypothesis that modulated RF fields affect malignant transformation or other cellular stress responses. Our group previously reported that DNA strand breaks were not induced in human cells exposed to 2.1425 GHz Wideband Code Division Multiple Access (W-CDMA) radiation up to 800 mW/kg from mobile radio base stations employing the IMT-2000 cellular system. In the current study, BALB/3T3 cells were continuously exposed to 2.1425 GHz W-CDMA RF fields at specific absorption rates (SARs) of 80 and 800 mW/kg for 6 weeks and malignant cell transformation was assessed. In addition, 3-methylcholanthrene (MCA)-treated cells were exposed to RF fields in a similar fashion, to assess for effects on tumor promotion. Finally, the effect of RF fields on tumor co-promotion was assessed in BALB/3T3 cells initiated with MCA and co-exposed to 12-O-tetradecanoylphorbol-13-acetate (TPA). At the end of the incubation period, transformation dishes were fixed, stained with Giemsa, and scored for morphologically transformed foci. No significant differences in transformation frequency were observed between the test groups exposed to RF signals and the sham-exposed negative controls in the non-, MCA-, or MCA plus TPA-treated cells. Our studies found no evidence to support the hypothesis that RF fields may affect malignant transformation. Our results suggest that exposure to low-level RF radiation of up to 800 mW/kg does not induce cell transformation, which causes tumor formation. (c) 2007 Wiley-Liss, Inc.

Application of an imputation method for geospatial inventory of forest structural attributes across multiple spatial scales in the Lake States, U.S.A

NASA Astrophysics Data System (ADS)

Deo, Ram K.

Credible spatial information characterizing the structure and site quality of forests is critical to sustainable forest management and planning, especially given the increasing demands and threats to forest products and services. Forest managers and planners are required to evaluate forest conditions over a broad range of scales, contingent on operational or reporting requirements. Traditionally, forest inventory estimates are generated via a design-based approach that involves generalizing sample plot measurements to characterize an unknown population across a larger area of interest. However, field plot measurements are costly and as a consequence spatial coverage is limited. Remote sensing technologies have shown remarkable success in augmenting limited sample plot data to generate stand- and landscape-level spatial predictions of forest inventory attributes. Further enhancement of forest inventory approaches that couple field measurements with cutting edge remotely sensed and geospatial datasets are essential to sustainable forest management. We evaluated a novel Random Forest based k Nearest Neighbors (RF-kNN) imputation approach to couple remote sensing and geospatial data with field inventory collected by different sampling methods to generate forest inventory information across large spatial extents. The forest inventory data collected by the FIA program of US Forest Service was integrated with optical remote sensing and other geospatial datasets to produce biomass distribution maps for a part of the Lake States and species-specific site index maps for the entire Lake State. Targeting small-area application of the state-of-art remote sensing, LiDAR (light detection and ranging) data was integrated with the field data collected by an inexpensive method, called variable plot sampling, in the Ford Forest of Michigan Tech to derive standing volume map in a cost-effective way. The outputs of the RF-kNN imputation were compared with independent validation datasets and extant map products based on different sampling and modeling strategies. The RF-kNN modeling approach was found to be very effective, especially for large-area estimation, and produced results statistically equivalent to the field observations or the estimates derived from secondary data sources. The models are useful to resource managers for operational and strategic purposes.

Application of Metamaterials to RF Energy Harvesting and Infrared Photodetection

NASA Astrophysics Data System (ADS)

Fowler, Clayton M.

Techniques for adapting metamaterials for the improvement of RF energy harvesting and infrared photodetection are demonstrated using experimental and computer simulation methods. Two methods for RF energy harvesting are experimentally demonstrated and supported by computer simulation. In the first method, a metamaterial perfect absorber (MPA) is made into a rectenna capable of harvesting RF energy and delivering power to a load by soldering Schottky diodes onto connected split ring resonator (SRR) structures composing the planar metasurface of the perfect absorber. The metamaterial rectenna is accompanied by a ground plane placed parallel to it, which forms a Fabry-Perot cavity between the metasurface and the ground plane. The Fabry-Perot cavity stores energy in the form of standing waves which is transferred to the SRR structures of the metasurface as AC currents that are rectified by the diodes to create DC power. This type of design enables highly efficient energy harvesting for low input power, creates a large antenna capture area, and uses elements with small electrical size, such that 100 uW of power (enough to operate simple devices) can be captured at ambient intensities 1 - 2 uW/cm2. Two designs using this method are presented, one that operates for linear polarizations at 0.9 GHz and a smaller polarization-independent design that operates around 1.5 GHz. In the second method, the energy stored in the standing waves of an MPA Fabry-Perot cavity is instead harvested by placing a separate energy harvesting antenna within the cavity. The cavity shapes and enhances the incident electric field, and then the separate energy harvesting antenna is designed to be inserted into the cavity so that its shape and/or radiation pattern matches the electric field lines within the cavity and maximally extracts the stored energy. This method allows for great customization of antenna design parameters, such as operating frequency, polarization dependence, and directionality, by swapping out different metasurface and antenna designs. Using this method, the amount of power harvested by a simple dipole rectenna placed within a cavity is improved by a factor of 18 as compared to what it would harvest by itself at an ambient intensity of 35 nW/cm2. Lastly, the addition of plasmonic structures to DWELL (quantum dot-in-a-well) infrared photodetectors is investigated by computer simulation. DWELL photodetectors have the potential to one day replace standard mercury cadmium telluride detectors by being cheaper alternatives with a higher operating temperature. The inclusion of gold plasmonic structure arrays into DWELL detectors enables excitation of surface plasmon polariton modes that increase the responsivity of the detector to incident infrared radiation. The peak responsivity of a DWELL detector is demonstrated to improve by a factor of 8 for a 1 mum thick layer of plasmonic structures and by a factor of 15 for a 2 mum thick layer. These works are steps forward in making RF energy harvesting practically useful and for improving infrared photodetector performance.

Around Marshall

NASA Image and Video Library

1963-01-15

At its founding, the Marshall Space Flight Center (MSFC) inherited the Army’s Jupiter and Redstone test stands, but much larger facilities were needed for the giant stages of the Saturn V. From 1960 to 1964, the existing stands were remodeled and a sizable new test area was developed. The new comprehensive test complex for propulsion and structural dynamics was unique within the nation and the free world, and they remain so today because they were constructed with foresight to meet the future as well as on going needs. Construction of the S-IC Static test stand complex began in 1961 in the west test area of MSFC, and was completed in 1964. The S-IC static test stand was designed to develop and test the 138-ft long and 33-ft diameter Saturn V S-IC first stage, or booster stage, weighing in at 280,000 pounds. Required to hold down the brute force of a 7,500,000-pound thrust produced by 5 F-1 engines, the S-IC static test stand was designed and constructed with the strength of hundreds of tons of steel and 12,000,000 pounds of cement, planted down to bedrock 40 feet below ground level. The foundation walls, constructed with concrete and steel, are 4 feet thick. The base structure consists of four towers with 40-foot-thick walls extending upward 144 feet above ground level. The structure was topped by a crane with a 135-foot boom. With the boom in the upright position, the stand was given an overall height of 405 feet, placing it among the highest structures in Alabama at the time. In addition to the stand itself, related facilities were constructed during this time. Built directly east of the test stand was the Block House, which served as the control center for the test stand. The two were connected by a narrow access tunnel which housed the cables for the controls. The F-1 Engine test stand was built north of the massive S-IC test stand. The F-1 test stand is a vertical engine firing test stand, 239 feet in elevation and 4,600 square feet in area at the base, and was designed to assist in the development of the F-1 Engine. Capability is provided for static firing of 1.5 million pounds of thrust using liquid oxygen and kerosene. Like the S-IC stand, the foundation of the F-1 stand is keyed into the bedrock approximately 40 feet below grade. Looking North, this aerial taken January 15, 1963, gives a closer view of the deep hole for the F-1 test stand site in the forefront. The S-IC test stand with towers prominent is to the right of center, and the Block House is seen left of center.

The interaction of the near-field plasma with antennas used in magnetic fusion research

NASA Astrophysics Data System (ADS)

Caughman, John

2015-09-01

Plasma heating and current drive using antennas in the Ion Cyclotron Range of Frequencies (ICRF) are important elements for the success of magnetic fusion. The antennas must operate in a harsh environment, where local plasma densities can be >1018/m3, magnetic fields can range from 0.2-5 Tesla, and antenna operating voltages can be >40 kV. This environment creates operational issues due to the interaction of the near-field of the antenna with the local plasma. In addition to parasitic losses in this plasma region, voltage and current distributions on the antenna structure lead to the formation of high electric fields and RF plasma sheaths, which can lead to enhanced particle and energy fluxes on the antenna and on surfaces intersected by magnetic field lines connected to or passing near the antenna. These issues are being studied using a simple electrode structure and a single-strap antenna on the Prototype Materials Plasma EXperiment (Proto-MPEX) at ORNL, which is a linear plasma device that uses an electron Bernstein wave heated helicon plasma source to create a high-density plasma suitable for use in a plasma-material interaction test stand. Several diagnostics are being used to characterize the near-field interactions, including double-Langmuir probes, a retarding field energy analyzer, and optical emission spectroscopy. The RF electric field is being studied utilizing Dynamic Stark Effect spectroscopy and Doppler-Free Saturation Spectroscopy. Recent experimental results and future plans will be presented. ORNL is managed by UT-Battelle, LLC, for the U.S. DOE under Contract DE-AC-05-00OR22725.

A-1 Test Stand modifications

NASA Image and Video Library

2011-09-14

Team members check the progress of a liquid nitrogen cold shock test on the A-1 Test Stand at Stennis Space Center on Sept. 15. The cold shock test is used to confirm the test stand's support system can withstand test conditions, when super-cold rocket engine propellant is piped. The A-1 Test Stand is preparing to conduct tests on the powerpack component of the J-2X rocket engine, beginning in early 2012.

1. TEST AREA 1115, SOUTH PART OF SUPPORT COMPLEX, LOOKING ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. TEST AREA 1-115, SOUTH PART OF SUPPORT COMPLEX, LOOKING TO EAST FROM ABOVE BUILDING 8655, THE FUEL STORAGE TANK FARM, IN FOREGROUND SHADOW. AT THE RIGHT IS BUILDING 8660, ELECTRICAL SUBSTATION; TO ITS LEFT IS BUILDING 8663, THE HELIUM COMPRESSION PLANT. THE LIGHT TONED STRUCTURE IN THE MIDDLE DISTANCE, CENTER, IS THE MACHINE SHOP FOR TEST STAND 1-3. IN THE FAR DISTANCE IS TEST STAND 1-A, WITH THE WHITE SPHERICAL TANKS, AND TEST STAND 2-A TO ITS RIGHT. ALONG THE HORIZON FROM FAR LEFT ARE TEST STAND 1-D, TEST STAND 1-C, WATER TANKS ABOVE TEST AREA 1-125, AND TEST STAND 1-B IN TEST AREA 1-120. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Leuhman Ridge near Highways 58 & 395, Boron, Kern County, CA

n/a

NASA Image and Video Library

1963-01-15

At its founding, the Marshall Space Flight Center (MSFC) inherited the Army’s Jupiter and Redstone test stands, but much larger facilities were needed for the giant stages of the Saturn V. From 1960 to 1964, the existing stands were remodeled and a sizable new test area was developed. The new comprehensive test complex for propulsion and structural dynamics was unique within the nation and the free world, and they remain so today because they were constructed with foresight to meet the future as well as on going needs. Construction of the S-IC Static test stand complex began in 1961 in the west test area of MSFC, and was completed in 1964. The S-IC static test stand was designed to develop and test the 138-ft long and 33-ft diameter Saturn V S-IC first stage, or booster stage, weighing in at 280,000 pounds. Required to hold down the brute force of a 7,500,000-pound thrust produced by 5 F-1 engines, the S-IC static test stand was designed and constructed with the strength of hundreds of tons of steel and 12,000,000 pounds of cement, planted down to bedrock 40 feet below ground level. The foundation walls, constructed with concrete and steel, are 4 feet thick. The base structure consists of four towers with 40-foot-thick walls extending upward 144 feet above ground level. The structure was topped by a crane with a 135-foot boom. With the boom in the upright position, the stand was given an overall height of 405 feet, placing it among the highest structures in Alabama at the time. In addition to the stand itself, related facilities were constructed during this time. Built directly east of the test stand was the Block House, which served as the control center for the test stand. The two were connected by a narrow access tunnel which housed the cables for the controls. The F-1 Engine test stand was built north of the massive S-IC test stand. The F-1 test stand is a vertical engine firing test stand, 239 feet in elevation and 4,600 square feet in area at the base, and was designed to assist in the development of the F-1 Engine. Capability is provided for static firing of 1.5 million pounds of thrust using liquid oxygen and kerosene. Like the S-IC stand, the foundation of the F-1 stand is keyed into the bedrock approximately 40 feet below grade. This aerial photograph, taken January 15, 1963 gives an overall view of the construction progress of the newly developed test complex. The large white building located in the center is the Block House. Just below and to the right of it is the S-IC test stand. The large hole to the left of the S-IC stand is the F-1 test stand site.

Busy test week

NASA Image and Video Library

2012-11-08

NASA recorded a historic week Nov. 5-9, conducting tests on all three stands in the E Test Complex at John C. Stennis Space Center. Inset images show the types of tests conducted on the E-1 Test Stand (right), the E-2 Test Stand (left) and the E-3 Test Stand (center). The E-1 photo is from an early October test and is provided courtesy of Blue Origin. Other photos are from tests conducted the week of Nov. 5.

Neurobiological effects of repeated radiofrequency exposures in male senescent rats.

PubMed

Bouji, Marc; Lecomte, Anthony; Gamez, Christelle; Blazy, Kelly; Villégier, Anne-Sophie

2016-11-01

The increasing use of mobile phones by aging people raises issues about the effects of radiofrequency electromagnetic fields (RF-EMF) on the aging central nervous system. Here, we tested if mobile phone RF-EMF exposures could exacerbate senescence-typical neurobiological deficits. Thus, aged (22-24 months) and young (4-6 months) adult male rats were subjected to head RF-EMF exposures (900 MHz, specific absorption rate (SAR) of 6 W/kg, 45 min/day for 1 month in restraint rockets). To assess senescence-typical neurobiological deficits, spatial memory, emotional memory, anxiety-related behavior, locomotor activity, interleukins (IL)-1β and 6, glial fibrillary acidic protein and corticosterone were measured. Aged rats presented deficits in spatial learning, exploration, anxiety-related behaviors, and increased hippocampal ILs and cortical IL-1β. Results showed that senescence-typical neurobiological deficits were not modified by RF-EMF exposures. RF-EMF-exposed rats (young and aged adults pooled) had decreased anxiety-related behaviors in the elevated plus maze. This study which is the first to assess RF-EMF exposures during late aging did not support the hypothesis of a specific cerebral vulnerability to RF-EMF during senescence. More investigations using longer RF-EMF exposures should be performed to conclude regarding the inoffensiveness of RF-EMF exposures.

A-2 Test Stand modification work

NASA Image and Video Library

2010-10-27

John C. Stennis Space Center employees install a new master interface tool on the A-2 Test Stand on Oct. 27, 2010. Until July 2009, the stand had been used for testing space shuttle main engines. With that test series complete, employees are preparing the stand for testing the next-generation J-2X rocket engine being developed. Testing of the new engine is scheduled to begin in 2011.

Design, fabrication, and high-gradient testing of an X -band, traveling-wave accelerating structure milled from copper halves

NASA Astrophysics Data System (ADS)

Argyropoulos, Theodoros; Catalan-Lasheras, Nuria; Grudiev, Alexej; Mcmonagle, Gerard; Rodriguez-Castro, Enrique; Syrachev, Igor; Wegner, Rolf; Woolley, Ben; Wuensch, Walter; Zha, Hao; Dolgashev, Valery; Bowden, Gorden; Haase, Andrew; Lucas, Thomas Geoffrey; Volpi, Matteo; Esperante-Pereira, Daniel; Rajamäki, Robin

2018-06-01

A prototype 11.994 GHz, traveling-wave accelerating structure for the Compact Linear Collider has been built, using the novel technique of assembling the structure from milled halves. The use of milled halves has many advantages when compared to a structure made from individual disks. These include the potential for a reduction in cost, because there are fewer parts, as well as a greater freedom in choice of joining technology because there are no rf currents across the halves' joint. Here we present the rf design and fabrication of the prototype structure, followed by the results of the high-power test and post-test surface analysis. During high-power testing the structure reached an unloaded gradient of 100 MV /m at a rf breakdown rate of less than 1.5 ×10-5 breakdowns /pulse /m with a 200 ns pulse. This structure has been designed for the CLIC testing program but construction from halves can be advantageous in a wide variety of applications.

An adjustable RF tuning element for microwave, millimeter wave, and submillimeter wave integrated circuits

NASA Technical Reports Server (NTRS)

Lubecke, Victor M.; Mcgrath, William R.; Rutledge, David B.

1991-01-01

Planar RF circuits are used in a wide range of applications from 1 GHz to 300 GHz, including radar, communications, commercial RF test instruments, and remote sensing radiometers. These circuits, however, provide only fixed tuning elements. This lack of adjustability puts severe demands on circuit design procedures and materials parameters. We have developed a novel tuning element which can be incorporated into the design of a planar circuit in order to allow active, post-fabrication tuning by varying the electrical length of a coplanar strip transmission line. It consists of a series of thin plates which can slide in unison along the transmission line, and the size and spacing of the plates are designed to provide a large reflection of RF power over a useful frequency bandwidth. Tests of this structure at 1 GHz to 3 Ghz showed that it produced a reflection coefficient greater than 0.90 over a 20 percent bandwidth. A 2 GHz circuit incorporating this tuning element was also tested to demonstrate practical tuning ranges. This structure can be fabricated for frequencies as high as 1000 GHz using existing micromachining techniques. Many commercial applications can benefit from this micromechanical RF tuning element, as it will aid in extending microwave integrated circuit technology into the high millimeter wave and submillimeter wave bands by easing constraints on circuit technology.

Electromagnetic fields produced by GSM cellular phones and heart rate variability.

PubMed

Parazzini, Marta; Ravazzani, Paolo; Tognola, Gabriella; Thuróczy, György; Molnar, Ferenc B; Sacchettini, Alessio; Ardesi, Gianluca; Mainardi, Luca Tommaso

2007-02-01

In this study, 26 healthy young volunteers were submitted to 900 MHz (2 W) GSM cellular phone exposure and to sham exposure in separate sessions. The study was designed to assess cardiac regulatory mechanism in different autonomic nervous system (ANS) states during exposure to low-intensity EMF. Rest-to-stand protocol was applied to evaluate ANS in quiet condition (rest, vagal prevalence) and after a sympathetic activation (stand). The procedure is conducted twice in a double-blind design: once with a genuine EMF exposure and once with a sham exposure (at least 24 h apart). During each session three-leads electrocardiograms were recorded and RR series extracted off-line. Time domain and frequency domain HRV parameters were calculated in every phase of the protocol and during different exposures. The analysis of the data show there was no statistically significant effect due to EMF exposure both on main (i.e., RR mean) and most of the other HRV parameters. A weak interaction between some HRV parameters (i.e., SDNN, TINN, and triangular index in time domain and LF power in frequency domain analysis) and RF exposure was observed and this effect seems to be gathered around the sympathetic response to stand.

Effects of improved fat meat products consumption on emergent cardiovascular disease markers of male volunteers at cardiovascular risk.

PubMed

Celada, Paloma; Sánchez-Muniz, Francisco J; Delgado-Pando, Gonzalo; Bastida, Sara; Rodilla, Manuel Espárrago; Jiménez-Colmenero, Francisco; Olmedilla-Alonso, Begoña

2016-12-01

High meat-product consumption has been related to cardiovascular disease (CVD). However, previous results suggest the benefits of consuming improved fat meat products on lipoprotein-cholesterol and anthropometric measurements. Present study aims to assess the effect of consuming different Pâté and Frankfurter formulations on emergent CVD biomarkers in male volunteers at increased CVD risk. Eighteen male volunteers with at least two CVD risk factors were enrolled in a sequentially controlled study where different pork-products were tested: reduced-fat (RF), omega-3-enriched-RF (n-3RF), and normal-fat (NF). Pork-products were consumed during 4-week periods separated by 4-week washout. The cardiometabolic index (CI), oxidized low density lipoproteins (oxLDL), apolipoproteins (Apo) A1 and B, homocysteine (tHcys), arylesterase (AE), C-reactive Protein (CRP), tumor necrotic factor-alpha (TNFα), and lipoprotein (a) (Lp(a)) were tested and some other related ratios calculated. AE, oxLDL and Lp(a), AE/HDLc, LDLc/Apo B, and AE/oxLDL rate of change were differently affected (P<0.01) by pork-products consumption. RF increased (P < 0.05) AE, AE/HDLc and AE/oxLDL ratios and decreased TNFα, tHcys; n-3RF increased (P < 0.001) AE, AE/HDLc and AE/oxLDL ratios and decreased (P < 0.05) Lp(a); while NF increased (P<0.05) oxLDL and Lp(a) levels. In conclusion, RF and n-3RF products affected positively the level of some emergent CVD markers. The high regular consumption of NF-products should be limited as significantly increased Lp(a) and oxLDL values. The high variability in response observed for some markers suggests the need to perform more studies to identify targets for RF- and n-3RF-products. Graphical Abstract Emergent CVD markers.

Evaluation of a microwave high-power reception-conversion array for wireless power transmission

NASA Technical Reports Server (NTRS)

Dickinson, R. M.

1975-01-01

Initial performance tests of a 24-sq m area array of rectenna elements are presented. The array is used as the receiving portion of a wireless microwave power transmission engineering verification test system. The transmitting antenna was located at a range of 1.54 km. Output dc voltage and power, input RF power, efficiency, and operating temperatures were obtained for a variety of dc load and RF incident power levels at 2388 MHz. Incident peak RF intensities of up to 170 mW/sq cm yielded up to 30.4 kW of dc output power. The highest derived collection-conversion efficiency of the array was greater than 80 percent.

Investigation and Prediction of RF Window Performance in APT Accelerators

DOE Office of Scientific and Technical Information (OSTI.GOV)

Humphries, S. Jr.

1997-05-01

The work described in this report was performed between November 1996 and May 1997 in support of the APT (Accelerator Production of Tritium) Program at Los Alamos National Laboratory. The goal was to write and to test computer programs for charged particle orbits in RF fields. The well-documented programs were written in portable form and compiled for standard personal computers for easy distribution to LANL researchers. They will be used in several APT applications including the following. Minimization of multipactor effects in the moderate {beta} superconducting linac cavities under design for the APT accelerator. Investigation of suppression techniques for electronmore » multipactoring in high-power RF feedthroughs. Modeling of the response of electron detectors for the protection of high power RF vacuum windows. In the contract period two new codes, Trak{_}RF and WaveSim, were completed and several critical benchmark etests were carried out. Trak{_}RF numerically tracks charged particle orbits in combined electrostatic, magnetostatic and electromagnetic fields. WaveSim determines frequency-domain RF field solutions and provides a key input to Trak{_}RF. The two-dimensional programs handle planar or cylindrical geometries. They have several unique characteristics.« less

38. HISTORIC CLOSER VIEW LOOKING WEST OF THE TEST STAND ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

38. HISTORIC CLOSER VIEW LOOKING WEST OF THE TEST STAND AND ROCKET DURING TEST FIRING NUMBER 10. NOTE THE NUMBER ALONG THE TOP RAIL OF THE STAND JUST TO THE RIGHT OF THE ROCKET, THIS NUMBER INDICATES WHAT NUMBER TEST IS BEING CONDUCTED. - Marshall Space Flight Center, Redstone Rocket (Missile) Test Stand, Dodd Road, Huntsville, Madison County, AL

49 CFR 210.33 - Operation standards (switcher locomotives, load cell test stands, car coupling operations, and...

Code of Federal Regulations, 2010 CFR

2010-10-01

... cell test stands, car coupling operations, and retarders). 210.33 Section 210.33 Transportation Other... (switcher locomotives, load cell test stands, car coupling operations, and retarders). (a) Measurement on receiving property of the noise emission levels from switcher locomotives, load cell test stands, car...

49 CFR 210.33 - Operation standards (switcher locomotives, load cell test stands, car coupling operations, and...

Code of Federal Regulations, 2013 CFR

2013-10-01

... cell test stands, car coupling operations, and retarders). 210.33 Section 210.33 Transportation Other... (switcher locomotives, load cell test stands, car coupling operations, and retarders). (a) Measurement on receiving property of the noise emission levels from switcher locomotives, load cell test stands, car...

49 CFR 210.33 - Operation standards (switcher locomotives, load cell test stands, car coupling operations, and...

Code of Federal Regulations, 2012 CFR

2012-10-01

... cell test stands, car coupling operations, and retarders). 210.33 Section 210.33 Transportation Other... (switcher locomotives, load cell test stands, car coupling operations, and retarders). (a) Measurement on receiving property of the noise emission levels from switcher locomotives, load cell test stands, car...

49 CFR 210.33 - Operation standards (switcher locomotives, load cell test stands, car coupling operations, and...

Code of Federal Regulations, 2014 CFR

2014-10-01

... cell test stands, car coupling operations, and retarders). 210.33 Section 210.33 Transportation Other... (switcher locomotives, load cell test stands, car coupling operations, and retarders). (a) Measurement on receiving property of the noise emission levels from switcher locomotives, load cell test stands, car...

49 CFR 210.33 - Operation standards (switcher locomotives, load cell test stands, car coupling operations, and...

Code of Federal Regulations, 2011 CFR

2011-10-01

... cell test stands, car coupling operations, and retarders). 210.33 Section 210.33 Transportation Other... (switcher locomotives, load cell test stands, car coupling operations, and retarders). (a) Measurement on receiving property of the noise emission levels from switcher locomotives, load cell test stands, car...

Novel radio-frequency gun structures for ultrafast relativistic electron diffraction.

PubMed

Musumeci, P; Faillace, L; Fukasawa, A; Moody, J T; O'Shea, B; Rosenzweig, J B; Scoby, C M

2009-08-01

Radio-frequency (RF) photoinjector-based relativistic ultrafast electron diffraction (UED) is a promising new technique that has the potential to probe structural changes at the atomic scale with sub-100 fs temporal resolution in a single shot. We analyze the limitations on the temporal and spatial resolution of this technique considering the operating parameters of a standard 1.6 cell RF gun (which is the RF photoinjector used for the first experimental tests of relativistic UED at Stanford Linear Accelerator Center; University of California, Los Angeles; Brookhaven National Laboratory), and study the possibility of employing novel RF structures to circumvent some of these limits.

1.5 MW RF Load for ITER

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ives, Robert Lawrence; Marsden, David; Collins, George

Calabazas Creek Research, Inc. developed a 1.5 MW RF load for the ITER fusion research facility currently under construction in France. This program leveraged technology developed in two previous SBIR programs that successfully developed high power RF loads for fusion research applications. This program specifically focused on modifications required by revised technical performance, materials, and assembly specification for ITER. This program implemented an innovative approach to actively distribute the RF power inside the load to avoid excessive heating or arcing associated with constructive interference. The new design implemented materials and assembly changes required to meet specifications. Critical components were builtmore » and successfully tested during the program.« less

A-1 Test Stand work

NASA Technical Reports Server (NTRS)

2010-01-01

Employees at NASA's John C. Stennis Space Center work to maneuver a structural steam beam into place on the A-1 Test Stand on Jan. 13. The beam was one of several needed to form the thrust takeout structure that will support a new thrust measurement system being installed on the stand for future rocket engine testing. Once lifted onto the stand, the beams had to be hoisted into place through the center of the test stand, with only two inches of clearance on each side. The new thrust measurement system represents a state-of-the-art upgrade from the equipment installed more than 40 years ago when the test stand was first constructed.

Serum levels of anti-CCP antibodies, anti-MCV antibodies and RF IgA in the follow-up of patients with rheumatoid arthritis treated with rituximab.

PubMed

Fabris, Martina; De Vita, Salvatore; Blasone, Nadia; Visentini, Daniela; Pezzarini, Elena; Pontarini, Elena; Fabro, Cinzia; Quartuccio, Luca; Mazzolini, Saulle; Curcio, Francesco; Tonutti, Elio

2010-11-01

Rheumatoid arthritis (RA) is characterized by the presence of circulating rheumatoid factor (RF) and anticitrullinated peptide antibodies (ACPA), which are positive in about 70-80% of patients. APCA have a higher specificity and therefore a higher diagnostic power than RF, but are less informative than RF in monitoring the course of the disease in patients under treatment. Recently, it has been reported that the anticitrullinated vimentin (a-MCV) antibody test can identify a particular subgroup of APCA that may be negative for anticyclic citrullinated peptide (a-CCP) antibodies. Concerning RF, the RF IgA isotype has been described as a more specific marker of erosive joint damage than total RF. The aim of our study was to monitor the levels of a-CCP, a-MCV, total RF and RF IgA in the follow-up of patients with RA treated with B-lymphocytedepletive rituximab (RTX), to detect any differences or peculiarities in patterns of these autoantibodies, especially in relation to their potential use as predictive markers of therapeutic response. We studied 30 patients with RA treated with RTX. All patients were previously unresponsive to at least 6 months of therapy with disease-modifying antirheumatic drugs (DMARDs; methotrexate, leflunomide, cyclosporine, chloroquine) and/or at least 6 months of therapy with anti-TNF biologics. The evaluation of response to RTX was made at month +6 using the EULAR criteria (DAS28). a-CCP, a-MCV, total RF and RF IgA were determined at baseline (before the first infusion of RTX) and after 1, 3 and 6 months. In serum samples obtained before treatment two cytokines essential for Blymphocyte proliferation, interleukin 6 (IL-6) and B-lymphocyte stimulator (BLyS) were also determined. In all patients a significant and consistent reduction in all the tested antibodies was found during follow-up, with no differences in respect of the degree of response to RTX. Of note, at baseline, generally a higher titre of all autoantibodies was seen in patients who then showed a better response to RTX. Finally, there were no differences in serum concentrations of IL-6 and BLyS in patients in relation to the presence or absence of the autoantibodies investigated, nor was there any significant correlation between the serum concentrations of the cytokines and the titres of the autoantibodies. Thus, neither a-MCV compared to a- CCP, nor RF IgA compared to routine total RF, provided any additional predictive information in the follow-up of patients with RA treated with RTX.

Historic tests

NASA Image and Video Library

2012-08-16

Two large-engine tests were conducted simultaneously for the first time at Stennis Space Center on Aug. 16. A plume on the left indicates a test on the facility's E-1 Test Stand. On the right, a finger of fire indicates a test under way on the A-1 Test Stand. In another first, both tests were conducted by female engineers. The image was taken from atop the facility's A-2 Test Stand, offering a panoramic view that includes the new A-3 Test Stand under construction to the left.

MR-compatibility assessment of MADPET4: a study of interferences between an SiPM-based PET insert and a 7 T MRI system.

PubMed

Omidvari, Negar; Topping, Geoffrey; Cabello, Jorge; Paul, Stephan; Schwaiger, Markus; Ziegler, Sibylle I

2018-05-01

Compromises in the design of a positron emission tomography (PET) insert for a magnetic resonance imaging (MRI) system should minimize the deterioration of image quality in both modalities, particularly when simultaneous demanding acquisitions are performed. In this work, the advantages of using individually read-out crystals with high-gain silicon photomultipliers (SiPMs) were studied with a small animal PET insert for a 7 T MRI system, in which the SiPM charge was transferred to outside the MRI scanner using coaxial cables. The interferences between the two systems were studied with three radio-frequency (RF) coil configurations. The effects of PET on the static magnetic field, flip angle distribution, RF noise, and image quality of various MRI sequences (gradient echo, spin echo, and echo planar imaging (EPI) at 1 H frequency, and chemical shift imaging at 13 C frequency) were investigated. The effects of fast-switching gradient fields and RF pulses on PET count rate were studied, while the PET insert and the readout electronics were not shielded. Operating the insert inside a 1 H volume coil, used for RF transmission and reception, limited the MRI to T1-weighted imaging, due to coil detuning and RF attenuation, and resulted in significant PET count loss. Using a surface receive coil allowed all tested MR sequences to be used with the insert, with 45-59% signal-to-noise ratio (SNR) degradation, compared to without PET. With a 1 H/ 13 C volume coil inside the insert and shielded by a copper tube, the SNR degradation was limited to 23-30% with all tested sequences. The insert did not introduce any discernible distortions into images of two tested EPI sequences. Use of truncated sinc shaped RF excitation pulses and gradient field switching had negligible effects on PET count rate. However, PET count rate was substantially affected by high-power RF block pulses and temperature variations due to high gradient duty cycles.

24. SATURN V Fl ENGINE TEST FIRING ON TEST STAND ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

24. SATURN V F-l ENGINE TEST FIRING ON TEST STAND 1A. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-A, Test Area 1-120, north end of Jupiter Boulevard, Boron, Kern County, CA

An MR/MRI compatible core holder with the RF probe immersed in the confining fluid.

PubMed

Shakerian, M; Balcom, B J

2018-01-01

An open frame RF probe for high pressure and high temperature MR/MRI measurements was designed, fabricated, and tested. The open frame RF probe was installed inside an MR/MRI compatible metallic core holder, withstanding a maximum pressure and temperature of 5000 psi and 80 °C. The open frame RF probe was tunable for both 1 H and 19 F resonance frequencies with a 0.2 T static magnetic field. The open frame structure was based on simple pillars of PEEK polymer upon which the RF probe was wound. The RF probe was immersed in the high pressure confining fluid during operation. The open frame structure simplified fabrication of the RF probe and significantly reduced the amount of polymeric materials in the core holder. This minimized the MR background signal detected. Phase encoding MRI methods were employed to map the spin density of a sulfur hexafluoride gas saturating a Berea core plug in the core holder. The SF 6 was imaged as a high pressure gas and as a supercritical fluid. Copyright © 2017 Elsevier Inc. All rights reserved.

An MR/MRI compatible core holder with the RF probe immersed in the confining fluid

NASA Astrophysics Data System (ADS)

Shakerian, M.; Balcom, B. J.

2018-01-01

An open frame RF probe for high pressure and high temperature MR/MRI measurements was designed, fabricated, and tested. The open frame RF probe was installed inside an MR/MRI compatible metallic core holder, withstanding a maximum pressure and temperature of 5000 psi and 80 °C. The open frame RF probe was tunable for both 1H and 19F resonance frequencies with a 0.2 T static magnetic field. The open frame structure was based on simple pillars of PEEK polymer upon which the RF probe was wound. The RF probe was immersed in the high pressure confining fluid during operation. The open frame structure simplified fabrication of the RF probe and significantly reduced the amount of polymeric materials in the core holder. This minimized the MR background signal detected. Phase encoding MRI methods were employed to map the spin density of a sulfur hexafluoride gas saturating a Berea core plug in the core holder. The SF6 was imaged as a high pressure gas and as a supercritical fluid.

Ginsenoside Rf, a component of ginseng, regulates lipoprotein metabolism through peroxisome proliferator-activated receptor {alpha}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Hyunghee; Gonzalez, Frank J.; Yoon, Michung

We investigated whether ginseng regulates lipoprotein metabolism by altering peroxisome proliferator-activated receptor {alpha} (PPAR{alpha})-mediated pathways, using a PPAR{alpha}-null mouse model. Administration of ginseng extract, ginsenosides, and ginsenoside Rf (Rf) to wild-type mice not only significantly increased basal levels of hepatic apolipoprotein (apo) A-I and C-III mRNA compared with wild-type controls, but also substantially reversed the reductions in mRNA levels of apo A-I and C-III expected following treatment with the potent PPAR{alpha} ligand Wy14,643. In contrast, no effect was detected in the PPAR{alpha}-null mice. Testing of eight main ginsenosides on PPAR{alpha} reporter gene expression indicated that Rf was responsible for themore » effects of ginseng on lipoprotein metabolism. Furthermore, the inhibition of PPAR{alpha}-dependent transactivation by Rf seems to occur at the level of DNA binding. These results demonstrate that ginseng component Rf regulates apo A-I and C-III mRNA and the actions of Rf on lipoprotein metabolism are mediated via interactions with PPAR{alpha}.« less

Detector power linearity requirements and verification techniques for TMI direct detection receivers

NASA Technical Reports Server (NTRS)

Reinhardt, Victor S. (Inventor); Shih, Yi-Chi (Inventor); Toth, Paul A. (Inventor); Reynolds, Samuel C. (Inventor)

1997-01-01

A system (36, 98) for determining the linearity of an RF detector (46, 106). A first technique involves combining two RF signals from two stable local oscillators (38, 40) to form a modulated RF signal having a beat frequency, and applying the modulated RF signal to a detector (46) being tested. The output of the detector (46) is applied to a low frequency spectrum analyzer (48) such that a relationship between the power levels of the first and second harmonics generated by the detector (46) of the beat frequency of the modulated RF signal are measured by the spectrum analyzer (48) to determine the linearity of the detector (46). In a second technique, an RF signal from a local oscillator (100) is applied to a detector (106) being tested through a first attenuator (102) and a second attenuator (104). The output voltage of the detector (106) is measured when the first attenuator (102) is set to a particular attenuation value and the second attenuator (104) is switched between first and second attenuation values. Further, the output voltage of the detector (106) is measured when the first attenuator (102) is set to another attenuation value, and the second attenuator (104) is again switched between the first and second attenuation values. A relationship between the voltage outputs determines the linearity of the detector (106).

Random Forest-Based Approach for Maximum Power Point Tracking of Photovoltaic Systems Operating under Actual Environmental Conditions.

PubMed

Shareef, Hussain; Mutlag, Ammar Hussein; Mohamed, Azah

2017-01-01

Many maximum power point tracking (MPPT) algorithms have been developed in recent years to maximize the produced PV energy. These algorithms are not sufficiently robust because of fast-changing environmental conditions, efficiency, accuracy at steady-state value, and dynamics of the tracking algorithm. Thus, this paper proposes a new random forest (RF) model to improve MPPT performance. The RF model has the ability to capture the nonlinear association of patterns between predictors, such as irradiance and temperature, to determine accurate maximum power point. A RF-based tracker is designed for 25 SolarTIFSTF-120P6 PV modules, with the capacity of 3 kW peak using two high-speed sensors. For this purpose, a complete PV system is modeled using 300,000 data samples and simulated using the MATLAB/SIMULINK package. The proposed RF-based MPPT is then tested under actual environmental conditions for 24 days to validate the accuracy and dynamic response. The response of the RF-based MPPT model is also compared with that of the artificial neural network and adaptive neurofuzzy inference system algorithms for further validation. The results show that the proposed MPPT technique gives significant improvement compared with that of other techniques. In addition, the RF model passes the Bland-Altman test, with more than 95 percent acceptability.

Random Forest-Based Approach for Maximum Power Point Tracking of Photovoltaic Systems Operating under Actual Environmental Conditions

PubMed Central

Shareef, Hussain; Mohamed, Azah

2017-01-01

Many maximum power point tracking (MPPT) algorithms have been developed in recent years to maximize the produced PV energy. These algorithms are not sufficiently robust because of fast-changing environmental conditions, efficiency, accuracy at steady-state value, and dynamics of the tracking algorithm. Thus, this paper proposes a new random forest (RF) model to improve MPPT performance. The RF model has the ability to capture the nonlinear association of patterns between predictors, such as irradiance and temperature, to determine accurate maximum power point. A RF-based tracker is designed for 25 SolarTIFSTF-120P6 PV modules, with the capacity of 3 kW peak using two high-speed sensors. For this purpose, a complete PV system is modeled using 300,000 data samples and simulated using the MATLAB/SIMULINK package. The proposed RF-based MPPT is then tested under actual environmental conditions for 24 days to validate the accuracy and dynamic response. The response of the RF-based MPPT model is also compared with that of the artificial neural network and adaptive neurofuzzy inference system algorithms for further validation. The results show that the proposed MPPT technique gives significant improvement compared with that of other techniques. In addition, the RF model passes the Bland–Altman test, with more than 95 percent acceptability. PMID:28702051

Stand for testing the electrical race car engine

NASA Astrophysics Data System (ADS)

Baier, M.; Franiasz, J.; Mierzwa, P.; Wylenzek, D.

2015-11-01

An engine test stand created especially for research of electrical race car is described in the paper. The car is an aim of Silesian Greenpower project whose participants build and test electrical vehicles to take part in international races in Great Britain. The engine test stand is used to test and measure the characteristics of vehicles and their engines. It has been designed particularly to test the electric cars engineered by students of Silesian Greenpower project. The article contains a description how the test stand works and shows its versatility in many areas. The paper presents both construction of the test stand, control system and sample results of conducted research. The engine test stand was designed and modified using PLM Siemens NX 8.5. The construction of the test stand is highly modular, which means it can be used both for testing the vehicle itself or for tests without the vehicle. The test stand has its own wheel, motor, powertrain and braking system with second engine. Such solution enables verifying various concepts without changing the construction of the vehicle. The control system and measurement system are realized by enabling National Instruments product myRIO (RIO - Reconfigurable Input/Output). This controller in combination with powerful LabVIEW environment performs as an advanced tool to control torque and speed simultaneously. It is crucial as far as the test stand is equipped in two motors - the one being tested and the braking one. The feedback loop is realized by an optical encoder cooperating with the rotor mounted on the wheel. The results of tests are shown live on the screen both as a chart and as single values. After performing several tests there is a report generated. The engine test stand is widely used during process of the Silesian Greenpower vehicle design. Its versatility enables powertrain testing, wheels and tires tests, thermal analysis and more.

Initial Simulations of RF Waves in Hot Plasmas Using the FullWave Code

NASA Astrophysics Data System (ADS)

Zhao, Liangji; Svidzinski, Vladimir; Spencer, Andrew; Kim, Jin-Soo

2017-10-01

FullWave is a simulation tool that models RF fields in hot inhomogeneous magnetized plasmas. The wave equations with linearized hot plasma dielectric response are solved in configuration space on adaptive cloud of computational points. The nonlocal hot plasma dielectric response is formulated by calculating the plasma conductivity kernel based on the solution of the linearized Vlasov equation in inhomogeneous magnetic field. In an rf field, the hot plasma dielectric response is limited to the distance of a few particles' Larmor radii, near the magnetic field line passing through the test point. The localization of the hot plasma dielectric response results in a sparse matrix of the problem thus significantly reduces the size of the problem and makes the simulations faster. We will present the initial results of modeling of rf waves using the Fullwave code, including calculation of nonlocal conductivity kernel in 2D Tokamak geometry; the interpolation of conductivity kernel from test points to adaptive cloud of computational points; and the results of self-consistent simulations of 2D rf fields using calculated hot plasma conductivity kernel in a tokamak plasma with reduced parameters. Work supported by the US DOE ``SBIR program.

A study on the antimicrobial efficacy of RF oxygen plasma and neem extract treated cotton fabrics

NASA Astrophysics Data System (ADS)

Vaideki, K.; Jayakumar, S.; Thilagavathi, G.; Rajendran, R.

2007-06-01

The paper deals with a thorough investigation on the antimicrobial activity of RF oxygen plasma and Azadirachtin (neem extract) treated cotton fabric. The hydrophilicity of cotton fabric was found to improve when treated with RF oxygen plasma. The process parameters such as electrode gap, time of exposure and oxygen pressure have been varied to study their effect on improving the hydrophilicity of the cotton fabric. The static immersion test has been carried out to assess the hydrophilicity of the oxygen plasma treated samples and the process parameters were optimized based on these test results. The formation of carbonyl group during surface modification in the plasma treated sample was analysed using FTIR studies. The surface morphology has been studied using SEM micrographs. The antimicrobial activity was imparted to the RF oxygen plasma treated samples using methanolic extract of neem leaves containing Azadirachtin. The antimicrobial activity of these samples has been analysed and compared with the activity of the cotton fabric treated with neem extract alone. The investigation reveals that the surface modification due to RF oxygen plasma was found to increase the hydrophilicity and hence the antimicrobial activity of the cotton fabric when treated with Azadirachtin.

Genotoxic effects of exposure to radiofrequency electromagnetic fields (RF-EMF) in HL-60 cells are not reproducible.

PubMed

Speit, Günter; Gminski, Richard; Tauber, Rudolf

2013-08-15

Conflicting results have been published regarding the induction of genotoxic effects by exposure to radiofrequency electromagnetic fields (RF-EMF). Various results indicating a genotoxic potential of RF-EMF were reported by the collaborative EU-funded REFLEX (Risk Evaluation of Potential Environmental Hazards From Low Energy Electromagnetic Field Exposure Using Sensitive in vitro Methods) project. There has been a long-lasting scientific debate about the reliability of the reported results and an attempt to reproduce parts of the results obtained with human fibroblasts failed. Another part of the REFLEX study was performed in Berlin with the human lymphoblastoid cell line HL-60; genotoxic effects of RF-EMF were measured by means of the comet assay and the micronucleus test. The plausibility and reliability of these results were also questioned. In order to contribute to a clarification of the biological significance of the reported findings, a repeat study was performed, involving scientists of the original study. Comet-assay experiments and micronucleus tests were performed under the same experimental conditions that had led to genotoxic effects in the REFLEX study. Here we report that the attempts to reproduce the induction of genotoxic effects by RF-EMF in HL-60 cells failed. No genotoxic effects of RF-EMF were measured in the repeat experiments. We could not find an explanation for the conflicting results. However, the negative repeat experiments suggest that the biological significance of genotoxic effects of RF-EMF reported by the REFLEX study should be re-assessed. Copyright © 2013 Elsevier B.V. All rights reserved.

View east northeast at Test Stand 'A' complex from road, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

View east northeast at Test Stand 'A' complex from road, showing Test Stand 'C' test tower in left background (Building 4217/E-18). Curved I-beam labeled '3-ton' is for small traveling hoist. Fuel tanks, propellant lines, and control panels have been removed from tower. - Jet Propulsion Laboratory Edwards Facility, Test Stand A, Edwards Air Force Base, Boron, Kern County, CA

1. VIEW NORTHEAST, LEFT TO RIGHT COLD CALIBRATION TEST STAND ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. VIEW NORTHEAST, LEFT TO RIGHT COLD CALIBRATION TEST STAND COLD CALIBRATION BLOCKHOUSE IN FOREGROUND. - Marshall Space Flight Center, East Test Area, Cold Calibration Test Stand, Huntsville, Madison County, AL

A-3 Test Stand work

NASA Image and Video Library

2011-07-29

Stennis Space Center employees have installed liquid oxygen and liquid hydrogen tanks atop the A-3 Test Stand, raising the structure to its full 300-foot height. The stand is being built to test next-generation rocket engines that could carry humans beyond low-Earth orbit into deep space. The A-3 Test Stand is scheduled for completion and activation in 2013.

40 CFR 201.27 - Procedures for: (1) Determining applicability of the locomotive load cell test stand standard and...

Code of Federal Regulations, 2010 CFR

2010-07-01

... applicability of the locomotive load cell test stand standard and switcher locomotive standard by noise measurement on a receiving property; (2) measurement of locomotive load cell test stands more than 120 meters... locomotive load cell test stand standard and switcher locomotive standard by noise measurement on a receiving...

40 CFR 201.27 - Procedures for: (1) Determining applicability of the locomotive load cell test stand standard and...

Code of Federal Regulations, 2014 CFR

2014-07-01

... applicability of the locomotive load cell test stand standard and switcher locomotive standard by noise measurement on a receiving property; (2) measurement of locomotive load cell test stands more than 120 meters... locomotive load cell test stand standard and switcher locomotive standard by noise measurement on a receiving...

40 CFR 201.27 - Procedures for: (1) Determining applicability of the locomotive load cell test stand standard and...

Code of Federal Regulations, 2012 CFR

2012-07-01

... applicability of the locomotive load cell test stand standard and switcher locomotive standard by noise measurement on a receiving property; (2) measurement of locomotive load cell test stands more than 120 meters... locomotive load cell test stand standard and switcher locomotive standard by noise measurement on a receiving...

40 CFR 201.27 - Procedures for: (1) Determining applicability of the locomotive load cell test stand standard and...

Code of Federal Regulations, 2011 CFR

2011-07-01

... applicability of the locomotive load cell test stand standard and switcher locomotive standard by noise measurement on a receiving property; (2) measurement of locomotive load cell test stands more than 120 meters... locomotive load cell test stand standard and switcher locomotive standard by noise measurement on a receiving...

40 CFR 201.27 - Procedures for: (1) Determining applicability of the locomotive load cell test stand standard and...

Code of Federal Regulations, 2013 CFR

2013-07-01

... applicability of the locomotive load cell test stand standard and switcher locomotive standard by noise measurement on a receiving property; (2) measurement of locomotive load cell test stands more than 120 meters... locomotive load cell test stand standard and switcher locomotive standard by noise measurement on a receiving...

Photographic copy of photograph, aerial view looking north and showing ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Photographic copy of photograph, aerial view looking north and showing Test Stand 'A' (at bottom), Test Stand 'B' (upper right), and a portion of Test Stand 'C' (top of view). Compare HAER CA-163-1 and 2 and note addition of liquid nitrogen storage tank (Building 4262/E-63) to west of Test Stand 'C' as well as various ancillary facilities located behind earth barriers near Test Stand 'C.' (JPL negative no. 384-3006-A, 12 December 1961) - Jet Propulsion Laboratory Edwards Facility, Edwards Air Force Base, Boron, Kern County, CA

RF HEATING OF MRI-ASSISTED CATHETER STEERING COILS FOR INTERVENTIONAL MRI

PubMed Central

Settecase, Fabio; Hetts, Steven W.; Martin, Alastair J.; Roberts, Timothy P. L.; Bernhardt, Anthony F.; Evans, Lee; Malba, Vincent; Saeed, Maythem; Arenson, Ronald L.; Kucharzyk, Walter; Wilson, Mark W.

2010-01-01

RATIONALE AND OBJECTIVES To assess magnetic resonance imaging (MRI) radiofrequency (RF) related heating of conductive wire coils used in magnetically steerable endovascular catheters. MATERIALS AND METHODS A 3-axis microcoil was fabricated onto a 1.8 Fr catheter tip. In vitro testing was performed in a 1.5 T MRI system using an agarose gel filled vessel phantom, a transmit/receive body RF coil and a steady state free precession (SSFP) pulse sequence, and a fluoroptic thermometry system. Temperature was measured without simulated blood flow at varying distances from magnet isocenter and varying flip angles. Additional experiments were performed with laser-lithographed single-axis microcoil-tipped microcatheters in air and in a saline bath with varied grounding of the microcoil wires. Preliminary in vivo evaluation of RF heating was performed in pigs at 1.5 T with coil-tipped catheters in various positions in the common carotid arteries with SSFP pulse sequence on and off, and under physiologic flow and zero flow conditions. RESULTS In tissue-mimicking agarose gel, RF heating resulted in a maximal temperature increase of 0.35°C after 15 minutes of imaging, 15 cm from magnet isocenter. For a single axis microcoil, maximal temperature increases were 0.73-1.91°C in air and 0.45-0.55°C in saline. In vivo, delayed contrast enhanced MRI revealed no evidence of vascular injury and histopathological sections from the common carotid arteries confirmed the lack of vascular damage. CONCLUSIONS Microcatheter tip microcoils for endovascular catheter steering in MRI experience minimal RF heating under the conditions tested. These data provide the basis for further in vivo testing of this promising technology for endovascular interventional MRI. PMID:21075019

Around Marshall

NASA Image and Video Library

1962-07-03

At its founding, the Marshall Space Flight Center (MSFC) inherited the Army’s Jupiter and Redstone test stands, but much larger facilities were needed for the giant stages of the Saturn V. From 1960 to 1964, the existing stands were remodeled and a sizable new test area was developed. The new comprehensive test complex for propulsion and structural dynamics was unique within the nation and the free world, and they remain so today because they were constructed with foresight to meet the future as well as on going needs. Construction of the S-IC Static test stand complex began in 1961 in the west test area of MSFC, and was completed in 1964. The S-IC static test stand was designed to develop and test the 138-ft long and 33-ft diameter Saturn V S-IC first stage, or booster stage, weighing in at 280,000 pounds. Required to hold down the brute force of a 7,500,000-pound thrust produced by 5 F-1 engines, the S-IC static test stand was designed and constructed with the strength of hundreds of tons of steel and 12,000,000 pounds of cement, planted down to bedrock 40 feet below ground level. The foundation walls, constructed with concrete and steel, are 4 feet thick. The base structure consists of four towers with 40-foot-thick walls extending upward 144 feet above ground level. The structure was topped by a crane with a 135-foot boom. With the boom in the upright position, the stand was given an overall height of 405 feet, placing it among the highest structures in Alabama at the time. In addition to the stand itself, related facilities were constructed during this time. North of the massive S-IC test stand, the F-1 Engine test stand was built. Designed to assist in the development of the F-1 Engine, the F-1 test stand is a vertical engine firing test stand, 239 feet in elevation and 4,600 square feet in area at the base. Capability was provided for static firing of 1.5 million pounds of thrust using liquid oxygen and kerosene. Like the S-IC stand, the foundation of the F-1 stand is keyed into the bedrock approximately 40 feet below grade. This photo depicts the construction of the F-1 test stand as of July 3, 1963. All four of its tower legs are well underway.

Around Marshall

NASA Image and Video Library

1963-09-05

At its founding, the Marshall Space Flight Center (MSFC) inherited the Army’s Jupiter and Redstone test stands, but much larger facilities were needed for the giant stages of the Saturn V. From 1960 to 1964, the existing stands were remodeled and a sizable new test area was developed. The new comprehensive test complex for propulsion and structural dynamics was unique within the nation and the free world, and they remain so today because they were constructed with foresight to meet the future as well as on going needs. Construction of the S-IC Static test stand complex began in 1961 in the west test area of MSFC, and was completed in 1964. The S-IC static test stand was designed to develop and test the 138-ft long and 33-ft diameter Saturn V S-IC first stage, or booster stage, weighing in at 280,000 pounds. Required to hold down the brute force of a 7,500,000-pound thrust produced by 5 F-1 engines, the S-IC static test stand was designed and constructed with the strength of hundreds of tons of steel and 12,000,000 pounds of cement, planted down to bedrock 40 feet below ground level. The foundation walls, constructed with concrete and steel, are 4 feet thick. The base structure consists of four towers with 40-foot-thick walls extending upward 144 feet above ground level. The structure was topped by a crane with a 135-foot boom. With the boom in the upright position, the stand was given an overall height of 405 feet, placing it among the highest structures in Alabama at the time. In addition to the stand itself, related facilities were constructed during this time. North of the massive S-IC test stand, the F-1 Engine test stand was built. Designed to assist in the development of the F-1 Engine, the F-1 test stand is a vertical engine firing test stand, 239 feet in elevation and 4,600 square feet in area at the base. Capability was provided for static firing of 1.5 million pounds of thrust using liquid oxygen and kerosene. Like the S-IC stand, the foundation of the F-1 stand is keyed into the bedrock approximately 40 feet below grade. This photo depicts the construction of the F-1 test stand as of September 5, 1963.

n/a

NASA Image and Video Library

1962-10-26

At its founding, the Marshall Space Flight Center (MSFC) inherited the Army’s Jupiter and Redstone test stands, but much larger facilities were needed for the giant stages of the Saturn V. From 1960 to 1964, the existing stands were remodeled and a sizable new test area was developed. The new comprehensive test complex for propulsion and structural dynamics was unique within the nation and the free world, and they remain so today because they were constructed with foresight to meet the future as well as on going needs. Construction of the S-IC Static test stand complex began in 1961 in the west test area of MSFC, and was completed in 1964. The S-IC static test stand was designed to develop and test the 138-ft long and 33-ft diameter Saturn V S-IC first stage, or booster stage, weighing in at 280,000 pounds. Required to hold down the brute force of a 7,500,000-pound thrust produced by 5 F-1 engines, the S-IC static test stand was designed and constructed with the strength of hundreds of tons of steel and 12,000,000 pounds of cement, planted down to bedrock 40 feet below ground level. The foundation walls, constructed with concrete and steel, are 4 feet thick. The base structure consists of four towers with 40-foot-thick walls extending upward 144 feet above ground level. The structure was topped by a crane with a 135-foot boom. With the boom in the upright position, the stand was given an overall height of 405 feet, placing it among the highest structures in Alabama at the time. In addition to the S-IC test stand, related facilities were built during this time. Built to the north of the massive S-IC test stand, was the F-1 Engine test stand. The F-1 test stand, a vertical engine firing test stand, 239 feet in elevation and 4,600 square feet in area at the base, was designed to assist in the development of the F-1 Engine. Capability was provided for static firing of 1.5 million pounds of thrust using liquid oxygen and kerosene. Like the S-IC stand, the foundation of the F-1 stand is keyed into the bedrock approximately 40 feet below grade. This photo, taken October 26, 1962, depicts the excavation process of the single engine F-1 stand.

Around Marshall

NASA Image and Video Library

1963-09-30

At its founding, the Marshall Space Flight Center (MSFC) inherited the Army’s Jupiter and Redstone test stands, but much larger facilities were needed for the giant stages of the Saturn V. From 1960 to 1964, the existing stands were remodeled and a sizable new test area was developed. The new comprehensive test complex for propulsion and structural dynamics was unique within the nation and the free world, and they remain so today because they were constructed with foresight to meet the future as well as on going needs. Construction of the S-IC Static test stand complex began in 1961 in the west test area of MSFC, and was completed in 1964. The S-IC static test stand was designed to develop and test the 138-ft long and 33-ft diameter Saturn V S-IC first stage, or booster stage, weighing in at 280,000 pounds. Required to hold down the brute force of a 7,500,000-pound thrust produced by 5 F-1 engines, the S-IC static test stand was designed and constructed with the strength of hundreds of tons of steel and 12,000,000 pounds of cement, planted down to bedrock 40 feet below ground level. The foundation walls, constructed with concrete and steel, are 4 feet thick. The base structure consists of four towers with 40-foot-thick walls extending upward 144 feet above ground level. The structure was topped by a crane with a 135-foot boom. With the boom in the upright position, the stand was given an overall height of 405 feet, placing it among the highest structures in Alabama at the time. In addition to the stand itself, related facilities were constructed during this time. North of the massive S-IC test stand, the F-1 Engine test stand was built. Designed to assist in the development of the F-1 Engine, the F-1 test stand is a vertical engine firing test stand, 239 feet in elevation and 4,600 square feet in area at the base. Capability was provided for static firing of 1.5 million pounds of thrust using liquid oxygen and kerosene. Like the S-IC stand, the foundation of the F-1 stand is keyed into the bedrock approximately 40 feet below grade. This photo depicts the construction of the F-1 test stand as of September 30, 1963.

Around Marshall

NASA Image and Video Library

1963-06-24

At its founding, the Marshall Space Flight Center (MSFC) inherited the Army’s Jupiter and Redstone test stands, but much larger facilities were needed for the giant stages of the Saturn V. From 1960 to 1964, the existing stands were remodeled and a sizable new test area was developed. The new comprehensive test complex for propulsion and structural dynamics was unique within the nation and the free world, and they remain so today because they were constructed with foresight to meet the future as well as on going needs. Construction of the S-IC Static test stand complex began in 1961 in the west test area of MSFC, and was completed in 1964. The S-IC static test stand was designed to develop and test the 138-ft long and 33-ft diameter Saturn V S-IC first stage, or booster stage, weighing in at 280,000 pounds. Required to hold down the brute force of a 7,500,000-pound thrust produced by 5 F-1 engines, the S-IC static test stand was designed and constructed with the strength of hundreds of tons of steel and 12,000,000 pounds of cement, planted down to bedrock 40 feet below ground level. The foundation walls, constructed with concrete and steel, are 4 feet thick. The base structure consists of four towers with 40-foot-thick walls extending upward 144 feet above ground level. The structure was topped by a crane with a 135-foot boom. With the boom in the upright position, the stand was given an overall height of 405 feet, placing it among the highest structures in Alabama at the time. In addition to the stand itself, related facilities were constructed during this time. North of the massive S-IC test stand, the F-1 Engine test stand was built. Designed to assist in the development of the F-1 Engine, the F-1 test stand is a vertical engine firing test stand, 239 feet in elevation and 4,600 square feet in area at the base. Capability was provided for static firing of 1.5 million pounds of thrust using liquid oxygen and kerosene. Like the S-IC stand, the foundation of the F-1 stand is keyed into the bedrock approximately 40 feet below grade. This photo depicts the construction of the F-1 test stand as of June 24, 1963. Two if its four tower legs are underway.

n/a

NASA Image and Video Library

1962-11-15

At its founding, the Marshall Space Flight Center (MSFC) inherited the Army’s Jupiter and Redstone test stands, but much larger facilities were needed for the giant stages of the Saturn V. From 1960 to 1964, the existing stands were remodeled and a sizable new test area was developed. The new comprehensive test complex for propulsion and structural dynamics was unique within the nation and the free world, and they remain so today because they were constructed with foresight to meet the future as well as on going needs. Construction of the S-IC Static test stand complex began in 1961 in the west test area of MSFC, and was completed in 1964. The S-IC static test stand was designed to develop and test the 138-ft long and 33-ft diameter Saturn V S-IC first stage, or booster stage, weighing in at 280,000 pounds. Required to hold down the brute force of a 7,500,000-pound thrust produced by 5 F-1 engines, the S-IC static test stand was designed and constructed with the strength of hundreds of tons of steel and 12,000,000 pounds of cement, planted down to bedrock 40 feet below ground level. The foundation walls, constructed with concrete and steel, are 4 feet thick. The base structure consists of four towers with 40-foot-thick walls extending upward 144 feet above ground level. The structure was topped by a crane with a 135-foot boom. With the boom in the upright position, the stand was given an overall height of 405 feet, placing it among the highest structures in Alabama at the time. In addition to the S-IC test stand, related facilities were built during this time. Built to the north of the massive S-IC test stand, was the F-1 Engine test stand. The F-1 test stand, a vertical engine firing test stand, 239 feet in elevation and 4,600 square feet in area at the base, was designed to assist in the development of the F-1 Engine. Capability was provided for static firing of 1.5 million pounds of thrust using liquid oxygen and kerosene. Like the S-IC stand, the foundation of the F-1 stand is keyed into the bedrock approximately 40 feet below grade. This photo, taken November 15, 1962, depicts the excavation process of the single engine F-1 stand site.

Around Marshall

NASA Image and Video Library

1963-10-22

At its founding, the Marshall Space Flight Center (MSFC) inherited the Army’s Jupiter and Redstone test stands, but much larger facilities were needed for the giant stages of the Saturn V. From 1960 to 1964, the existing stands were remodeled and a sizable new test area was developed. The new comprehensive test complex for propulsion and structural dynamics was unique within the nation and the free world, and they remain so today because they were constructed with foresight to meet the future as well as on going needs. Construction of the S-IC Static test stand complex began in 1961 in the west test area of MSFC, and was completed in 1964. The S-IC static test stand was designed to develop and test the 138-ft long and 33-ft diameter Saturn V S-IC first stage, or booster stage, weighing in at 280,000 pounds. Required to hold down the brute force of a 7,500,000-pound thrust produced by 5 F-1 engines, the S-IC static test stand was designed and constructed with the strength of hundreds of tons of steel and 12,000,000 pounds of cement, planted down to bedrock 40 feet below ground level. The foundation walls, constructed with concrete and steel, are 4 feet thick. The base structure consists of four towers with 40-foot-thick walls extending upward 144 feet above ground level. The structure was topped by a crane with a 135-foot boom. With the boom in the upright position, the stand was given an overall height of 405 feet, placing it among the highest structures in Alabama at the time. In addition to the stand itself, related facilities were constructed during this time. Northeast of the massive S-IC test stand, the F-1 Engine test stand was built. The F-1 test stand is a vertical engine firing test stand, 239 feet in elevation and 4,600 square feet in area at the base, and was designed to assist in the development of the F-1 Engine. Capability was provided for static firing of 1.5 million pounds of thrust using liquid oxygen and kerosene. Like the S-IC stand, the foundation of the F-1 stand is keyed into the bedrock approximately 40 feet below grade. This photo depicts the fuel tanks that housed kerosene and just beyond those is the F-1 test stand.

23. "A CAPTIVE ATLAS MISSILE EXPLODED DURING THE TEST ON ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

23. "A CAPTIVE ATLAS MISSILE EXPLODED DURING THE TEST ON TEST STAND 1-A, 27 MARCH 1959, PUTTING THAT TEST STAND OUT-OF-COMMISSION. STAND WAS NOT REPAIRED FOR THE ATLAS PROGRAM BUT TRANSFERRED TO ROCKETDYNE AND MODIFIED FOR THE F-l ENGINE PROGRAM." - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-A, Test Area 1-120, north end of Jupiter Boulevard, Boron, Kern County, CA

8. TEST STAND 15, INVERTED ENGINE FIRING TEST, CIRCA 1963. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

8. TEST STAND 1-5, INVERTED ENGINE FIRING TEST, CIRCA 1963. Original is a color print. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-5, Test Area 1-115, northwest end of Saturn Boulevard, Boron, Kern County, CA

A-3 Test Stand work continues

NASA Image and Video Library

2011-04-22

Stennis Space Center employees continue work on the A-3 Test Stand test cell. The stand is being built to test next-generation rocket engines that could carry humans beyond low-Earth orbit into deep space.

9. COLD CALIBRATION TEST STAND (H1) FROM LEFT TO RIGHT ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

9. COLD CALIBRATION TEST STAND (H-1) FROM LEFT TO RIGHT - WORK BENCH, CONTROL PANEL, CHEMICAL TANK. - Marshall Space Flight Center, East Test Area, Cold Calibration Test Stand, Huntsville, Madison County, AL

5. EAST SIDE, TEST STAND AND ITS SUPERSTRUCTURE. Edwards ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

5. EAST SIDE, TEST STAND AND ITS SUPERSTRUCTURE. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-A, Test Area 1-120, north end of Jupiter Boulevard, Boron, Kern County, CA

PERSPECTIVE VIEW LOOKING NORTHEAST AT THE TEST STAND, NOTE THE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

PERSPECTIVE VIEW LOOKING NORTHEAST AT THE TEST STAND, NOTE THE SERVICE AND SUPPORT BUILDINGS TO THE LEFT AND RIGHT OF THE TEST STAND. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

Influence of Ramadan Fasting on Anaerobic Performance and Recovery Following Short time High Intensity Exercise.

PubMed

Karli, Umid; Guvenc, Alpay; Aslan, Alper; Hazir, Tahir; Acikada, Caner

2007-01-01

The aim of this study was to investigate the effects of Ramadan fasting on anaerobic power and capacity and the removal rate of lactate after short time high intensity exercise in power athletes. Ten male elite power athletes (2 wrestlers, 7 sprinters and 1 thrower, aged 20-24 yr, mean age 22.30 ± 1.25 yr) participated in this study. The subjects were tested three times [3 days before the beginning of Ramadan (Pre-RF), the last 3 days of Ramadan (End-RF) and the last 3 days of the 4(th) week after the end of Ramadan (After-RF)]. Anaerobic power and capacity were measured by using the Wingate Anaerobic Test (WAnT) at Pre-RF, End-RF and After- RF. Capillary blood samples for lactate analyses and heart rate recordings were taken at rest, immediately after WAnT and throughout the recovery period. Repeated measures of ANOVA indicated that there were no significant changes in body weight, body mass index, fat free mass, percentage of body fat, daily sleeping time and daily caloric intake associated with Ramadan fasting. No significant changes were found in total body water either, but urinary density measured at End-RF was significantly higher than After-RF. Similarity among peak HR and peak LA values at Pre-RF, End- RF and After-RF demonstrated that cardiovascular and metabolic stress caused by WAnT was not affected by Ramadan fasting. In addition, no influence of Ramadan fasting on anaerobic power and capacity and removal rate of LA from blood following high intensity exercise was observed. The results of this study revealed that if strength-power training is performed regularly and daily food intake, body fluid balance and daily sleeping time are maintained as before Ramadan, Ramadan fasting will not have adverse effects on body composition, anaerobic power and capacity, and LA metabolism during and after high intensity exercise in power athletes. Key pointsNo significant changes were assessed on body composition, daily sleeping time and caloric intake, and body fluid balance in regularly trained power athletes during Ramadan fasting.Ramadan fasting has no adverse effect on power outputs of short time high intensity exercise.No influence of Ramadan fasting on LA metabolism during high intensity exercise and passive recovery in regularly trained power athletes.

Retrieving Coherent Receiver Function Images with Dense Arrays

NASA Astrophysics Data System (ADS)

Zhong, M.; Zhan, Z.

2016-12-01

Receiver functions highlight converted phases (e.g., Ps, PpPs, sP) and have been widely used to study seismic interfaces. With a dense array, receiver functions (RFs) at multiple stations form a RF image that can provide more robust/detailed constraints. However, due to noise in data, non-uniqueness of deconvolution, and local structures that cannot be detected across neighboring stations, traditional RF images are often noisy and hard to interpret. Previous attempts to enhance coherence by stacking RFs from multiple events or post-filtering the RF images have not produced satisfactory improvements. Here, we propose a new method to retrieve coherent RF images with dense arrays. We take advantage of the waveform coherency at neighboring stations and invert for a small number of coherent arrivals for their RFs. The new RF images contain only the coherent arrivals required to fit data well. Synthetic tests and preliminary applications on real data demonstrate that the new RF images are easier to interpret and improve our ability to infer Earth structures using receiver functions.

OPAL: prediction of MoRF regions in intrinsically disordered protein sequences.

PubMed

Sharma, Ronesh; Raicar, Gaurav; Tsunoda, Tatsuhiko; Patil, Ashwini; Sharma, Alok

2018-06-01

Intrinsically disordered proteins lack stable 3-dimensional structure and play a crucial role in performing various biological functions. Key to their biological function are the molecular recognition features (MoRFs) located within long disordered regions. Computationally identifying these MoRFs from disordered protein sequences is a challenging task. In this study, we present a new MoRF predictor, OPAL, to identify MoRFs in disordered protein sequences. OPAL utilizes two independent sources of information computed using different component predictors. The scores are processed and combined using common averaging method. The first score is computed using a component MoRF predictor which utilizes composition and sequence similarity of MoRF and non-MoRF regions to detect MoRFs. The second score is calculated using half-sphere exposure (HSE), solvent accessible surface area (ASA) and backbone angle information of the disordered protein sequence, using information from the amino acid properties of flanks surrounding the MoRFs to distinguish MoRF and non-MoRF residues. OPAL is evaluated using test sets that were previously used to evaluate MoRF predictors, MoRFpred, MoRFchibi and MoRFchibi-web. The results demonstrate that OPAL outperforms all the available MoRF predictors and is the most accurate predictor available for MoRF prediction. It is available at http://www.alok-ai-lab.com/tools/opal/. ashwini@hgc.jp or alok.sharma@griffith.edu.au. Supplementary data are available at Bioinformatics online.

Electron bunch energy and phase feed-forward stabilization system for the Mark V RF-linac free-electron laser

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hadmack, M. R.; Kowalczyk, J. M. D.; Lienert, B. R.

2013-06-15

An amplitude and phase compensation system has been developed and tested at the University of Hawai'i for the optimization of the RF drive system to the Mark V free-electron laser. Temporal uniformity of the RF drive is essential to the generation of an electron beam suitable for optimal free-electron laser performance and the operation of an inverse Compton scattering x-ray source. The design of the RF measurement and compensation system is described in detail and the results of RF phase compensation are presented. Performance of the free-electron laser was evaluated by comparing the measured effects of phase compensation with themore » results of a computer simulation. Finally, preliminary results are presented for the effects of amplitude compensation on the performance of the complete system.« less

Analysis and measurement of the transfer matrix of a 9-cell, 1.3-GHz superconducting cavity

DOE PAGES

Halavanau, A.; Eddy, N.; Edstrom, D.; ...

2017-04-13

Superconducting linacs are capable of producing intense, stable, high-quality electron beams that have found widespread applications in science and industry. Here, the 9-cell, 1.3-GHz superconducting standing-wave accelerating rf cavity originally developed for e +/e - linear-collider applications has been broadly employed in various superconducting-linac designs. In this paper we discuss the transfer matrix of such a cavity and present its measurement performed at the Fermilab Accelerator Science and Technology (FAST) facility. Finally, the experimental results are found to be in agreement with analytical calculations and numerical simulations.

KSC-2009-3753

NASA Image and Video Library

2009-06-18

CAPE CANAVERAL, Fla. – NASA's Lunar Reconnaissance Orbiter, or LRO, and NASA's Lunar Crater Observation and Sensing Satellite, known as LCROSS, stand ready for liftoff on an Atlas V/Centaur rocket from Launch Pad 41 at Cape Canaveral Air Force Station in Florida. LRO and LCROSS are the first missions in NASA's plan to return humans to the moon and begin establishing a lunar outpost by 2020. The LRO also includes seven instruments that will help NASA characterize the moon's surface: DIVINER, LAMP, LEND, LOLA , CRATER, Mini-RF and LROC. Launch is scheduled for 5:12 p.m. EDT June 18. Photo credit: NASA/Ken Thornsley

Characterization of a Prototype Radio Frequency Space Environment Path Emulator for Evaluating Spacecraft Ranging Hardware

NASA Technical Reports Server (NTRS)

Mitchell, Jason W.; Baldwin, Philip J.; Kurichh, Rishi; Naasz, Bo J.; Luquette, Richard J.

2007-01-01

The Formation Flying Testbed (FFTB) at the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) provides a hardware-in-the-loop test environment for formation navigation and control. The facility is evolving as a modular, hybrid, dynamic simulation facility for end-to-end guidance, navigation and control (GN&C) design and analysis of formation flying spacecraft. The core capabilities of the FFTB, as a platform for testing critical hardware and software algorithms in-the-loop, have expanded to include S-band Radio Frequency (RF) modems for interspacecraft communication and ranging. To enable realistic simulations that require RF ranging sensors for relative navigation, a mechanism is needed to buffer the RF signals exchanged between spacecraft that accurately emulates the dynamic environment through which the RF signals travel, including the effects of the medium, moving platforms, and radiated power. The Path Emulator for Radio Frequency Signals (PERFS), currently under development at NASA GSFC, provides this capability. The function and performance of a prototype device are presented.

Equivalence of Laptop and Tablet Administrations of the Minnesota Multiphasic Personality Inventory-2 Restructured Form.

PubMed

Menton, William H; Crighton, Adam H; Tarescavage, Anthony M; Marek, Ryan J; Hicks, Adam D; Ben-Porath, Yossef S

2017-06-01

The present study investigated the comparability of laptop computer- and tablet-based administration modes for the Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF). Employing a counterbalanced within-subjects design, the MMPI-2-RF was administered via both modes to a sample of college undergraduates ( N = 133). Administration modes were compared in terms of mean scale scores, internal consistency, test-retest consistency, external validity, and administration time. Mean scores were generally similar, and scores produced via both methods appeared approximately equal in terms of internal consistency and test-retest consistency. Scores from the two modalities also evidenced highly similar patterns of associations with external criteria. Notably, tablet administration of the MMPI-2-RF was substantially longer than laptop administration in the present study (mean difference 7.2 minutes, Cohen's d = .95). Overall, results suggest that varying administration mode between laptop and tablet has a negligible influence on MMPI-2-RF scores, providing evidence that these modes of administration can be considered psychometrically equivalent.

The history of bacteriologic concepts of rheumatic fever and rheumatoid arthritis.

PubMed

Benedek, Thomas G

2006-10-01

Review of the development of etiologic and pathogenetic concepts of rheumatic fever (RF) and rheumatoid arthritis (RA) from the beginning of clinical bacteriology to the discovery of antibiotics. Analysis of English and German language publications pertaining to bacteriology and "rheumatism" between the 1870s and 1940s. Early in the 20th century there was a widely held belief that a microbial cause would eventually be found for most diseases. This encouraged pursuit of the intermittent findings of positive blood and synovial fluid cultures in cases of RF and RA. Development of a streptococcal agglutination test supported the erroneous belief that RA is a streptococcal infection, while the simultaneous development of other immunologic tests for streptococci suggested that a hemolytic streptococcus was etiologic in RF. Table 1 provides a chronology of major events supporting and retarding resolutions. Much of the conflicting data and inferences regarding the etiology of RF and RA can be attributed to the absence or inadequacy of controls in observations of clinical cohorts and laboratory experiments.

Millimeter Wave Communications Program: Link Tests of High Speed Digital Radio Set AN/GRC-173 (XW-1)

DTIC Science & Technology

1975-01-01

Terrence Kelly, John Mutty, Edward Rich, James Roche, William J. Smxth, Carson Tsao, and David Trask. Hugh N. Siegel (DCCW) was the RADC...shelter, except for the parabolic dish and front-feed antenna system, which is mast-mounted adjacent to the shelter and connected to an rf input...Equipment: All rf and digital units 8. POWER SUPPLIES Quantity: 1 for rf , 1 for digital Primary Power: 120/240V +10% single phase, 47 - 420 Hz

A test-retest dataset for assessing long-term reliability of brain morphology and resting-state brain activity.

PubMed

Huang, Lijie; Huang, Taicheng; Zhen, Zonglei; Liu, Jia

2016-03-15

We present a test-retest dataset for evaluation of long-term reliability of measures from structural and resting-state functional magnetic resonance imaging (sMRI and rfMRI) scans. The repeated scan dataset was collected from 61 healthy adults in two sessions using highly similar imaging parameters at an interval of 103-189 days. However, as the imaging parameters were not completely identical, the reliability estimated from this dataset shall reflect the lower bounds of the true reliability of sMRI/rfMRI measures. Furthermore, in conjunction with other test-retest datasets, our dataset may help explore the impact of different imaging parameters on reliability of sMRI/rfMRI measures, which is especially critical for assessing datasets collected from multiple centers. In addition, intelligence quotient (IQ) was measured for each participant using Raven's Advanced Progressive Matrices. The data can thus be used for purposes other than assessing reliability of sMRI/rfMRI alone. For example, data from each single session could be used to associate structural and functional measures of the brain with the IQ metrics to explore brain-IQ association.

CLOSEUP VIEW LOOKING SOUTH AT THE SATURN I TEST STAND, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

CLOSE-UP VIEW LOOKING SOUTH AT THE SATURN I TEST STAND, NOTE THE INTERPRETIVE SIGN EXPLAINING THE HISTORIC NATURE OF THE SATURN I TEST STAND. - Marshall Space Flight Center, Saturn Propulsion & Structural Test Facility, East Test Area, Huntsville, Madison County, AL

43. HISTORIC VIEW LOOKING SOUTHWEST AT THE TEST STAND WITH ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

43. HISTORIC VIEW LOOKING SOUTHWEST AT THE TEST STAND WITH A REDSTONE ROCKET BEING FUELED AND PREPARED FOR TESTING. - Marshall Space Flight Center, Redstone Rocket (Missile) Test Stand, Dodd Road, Huntsville, Madison County, AL

3. "TEST STAND NO. 13, EXCAVATION PLAN & SECTIONS." Specifications ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

3. "TEST STAND NO. 1-3, EXCAVATION PLAN & SECTIONS." Specifications No. ENG 04-353-50-10; Drawing No. 60-0906; no sheet number within title block; D.O. SERIES 1109/10. Stamped: AS BUILT. No revisions or revision dates. Last work date on this drawing "Checked by EAG, 1/31/49." Though this drawing is specific to Test Stand 1-3, it also illustrates the general methods used for excavation design and retaining wall construction at Test Stand 1-5. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-3, Test Area 1-115, northwest end of Saturn Boulevard, Boron, Kern County, CA

1. Credit PSR. This view displays the north and west ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. Credit PSR. This view displays the north and west facades of Test Stand "G" (Vibration Facility) as seen when looking east southeast (110°). Test Stand "G" no longer houses the vibrator; it now houses an autoclave due to the changing nature of the testing work. The Vibration Facility was Test Stand "G"'s historic function. Test Stand "E" is at the far right. The Vibration Facility subjected motor and engine assemblies to various vibration patterns in order to simulate flight conditions and evaluate the durability of engine and motor designs. - Jet Propulsion Laboratory Edwards Facility, Test Stand G, Edwards Air Force Base, Boron, Kern County, CA

Test Methods for Telemetry Systems and Subsystems. Volume 2: Test Methods for Telemetry Radio Frequency (RF) Subsystems

DTIC Science & Technology

2012-09-01

downconverters; telemetry RF preamplifiers; telemetry multicouplers; telemetry receivers 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT Same as...Continuing Engineering Education Program, George Washington University , 1994. A-5 Figure A-2. Graphical representation of intercept point...NFdb) is expressed in decibels and noise factor (nf ) in decimal units. For example, a noise figure of 3 dB corresponds to a noise factor of 2

A COMPACTRIO-BASED BEAM LOSS MONITOR FOR THE SNS RF TEST CAVE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blokland, Willem; Armstrong, Gary A

2009-01-01

An RF Test Cave has been built at the Spallation Neutron Source (SNS) to be able to test RF cavities without interfering the SNS accelerator operations. In addition to using thick concrete wall to minimize radiation exposure, a Beam Loss Monitor (BLM) must abort the operation within 100 usec when the integrated radiation within the cave exceeds a threshold. We choose the CompactRIO platform to implement the BLM based on its performance, cost-effectiveness, and rapid development. Each in/output module is connected through an FPGA to provide point-by-point processing. Every 10 usec the data is acquired analyzed and compared to themore » threshold. Data from the FPGA is transferred using DMA to the real-time controller, which communicates to a gateway PC to talk to the SNS control system. The system includes diagnostics to test the hardware and integrates the losses in real-time. In this paper we describe our design, implementation, and results« less

Hepatic Radiofrequency Ablation–induced Stimulation of Distant Tumor Growth Is Suppressed by c-Met Inhibition

PubMed Central

Kumar, Gaurav; Moussa, Marwan; Wang, Yuanguo; Rozenblum, Nir; Galun, Eithan; Goldberg, S. Nahum

2016-01-01

Purpose To elucidate how hepatic radiofrequency (RF) ablation affects distant extrahepatic tumor growth by means of two key molecular pathways. Materials and Methods Rats were used in this institutional animal care and use committee–approved study. First, the effect of hepatic RF ablation on distant subcutaneous in situ R3230 and MATBIII breast tumors was evaluated. Animals were randomly assigned to standardized RF ablation, sham procedure, or no treatment. Tumor growth rate was measured for 3½ to 7 days. Then, tissue was harvested for Ki-67 proliferative indexes and CD34 microvascular density. Second, hepatic RF ablation was performed for hepatocyte growth factor (HGF), vascular endothelial growth factor (VEGF), and c-Met receptor expression measurement in periablational rim, serum, and distant tumor 24 hours to 7 days after ablation. Third, hepatic RF ablation was combined with either a c-Met inhibitor (PHA-665752) or VEGF receptor inhibitor (semaxanib) and compared with sham or drug alone arms to assess distant tumor growth and growth factor levels. Finally, hepatic RF ablation was performed in rats with c-Met–negative R3230 tumors for comparison with the native c-Met–positive line. Tumor size and immunohistochemical quantification at day 0 and at sacrifice were compared with analysis of variance and the two-tailed Student t test. Tumor growth curves before and after treatment were analyzed with linear regression analysis to determine mean slopes of pre- and posttreatment growth curves on a per-tumor basis and were compared with analysis of variance and paired two-tailed t tests. Results After RF ablation of normal liver, distant R3230 tumors were substantially larger at 7 days compared with tumors treated with the sham procedure and untreated tumors, with higher growth rates and tumor cell proliferation. Similar findings were observed in MATBIII tumors. Hepatic RF ablation predominantly increased periablational and serum HGF and downstream distant tumor VEGF levels. Compared with RF ablation alone, RF ablation combined with adjuvant PHA-665752 or semaxanib reduced distant tumor growth, proliferation, and microvascular density. For c-Met–negative tumors, hepatic RF ablation did not increase distant tumor growth, proliferation, or microvascular density compared with sham treatment. Conclusion RF ablation of normal liver can stimulate distant subcutaneous tumor growth mediated by HGF/c-Met pathway and VEGF activation. This effect was not observed in c-Met–negative tumors and can be blocked with adjuvant c-Met and VEGF inhibitors. © RSNA, 2015 PMID:26418615

Large-scale generic test stand for testing of multiple configurations of air filters utilizing a range of particle size distributions

NASA Astrophysics Data System (ADS)

Giffin, Paxton K.; Parsons, Michael S.; Unz, Ronald J.; Waggoner, Charles A.

2012-05-01

The Institute for Clean Energy Technology (ICET) at Mississippi State University has developed a test stand capable of lifecycle testing of high efficiency particulate air filters and other filters specified in American Society of Mechanical Engineers Code on Nuclear Air and Gas Treatment (AG-1) filters. The test stand is currently equipped to test AG-1 Section FK radial flow filters, and expansion is currently underway to increase testing capabilities for other types of AG-1 filters. The test stand is capable of producing differential pressures of 12.45 kPa (50 in. w.c.) at volumetric air flow rates up to 113.3 m3/min (4000 CFM). Testing is performed at elevated and ambient conditions for temperature and relative humidity. Current testing utilizes three challenge aerosols: carbon black, alumina, and Arizona road dust (A1-Ultrafine). Each aerosol has a different mass median diameter to test loading over a wide range of particles sizes. The test stand is designed to monitor and maintain relative humidity and temperature to required specifications. Instrumentation is implemented on the upstream and downstream sections of the test stand as well as on the filter housing itself. Representative data are presented herein illustrating the test stand's capabilities. Digital images of the filter pack collected during and after testing is displayed after the representative data are discussed. In conclusion, the ICET test stand with AG-1 filter testing capabilities has been developed and hurdles such as test parameter stability and design flexibility overcome.

Microfluidic stretchable RF electronics.

PubMed

Cheng, Shi; Wu, Zhigang

2010-12-07

Stretchable electronics is a revolutionary technology that will potentially create a world of radically different electronic devices and systems that open up an entirely new spectrum of possibilities. This article proposes a microfluidic based solution for stretchable radio frequency (RF) electronics, using hybrid integration of active circuits assembled on flex foils and liquid alloy passive structures embedded in elastic substrates, e.g. polydimethylsiloxane (PDMS). This concept was employed to implement a 900 MHz stretchable RF radiation sensor, consisting of a large area elastic antenna and a cluster of conventional rigid components for RF power detection. The integrated radiation sensor except the power supply was fully embedded in a thin elastomeric substrate. Good electrical performance of the standalone stretchable antenna as well as the RF power detection sub-module was verified by experiments. The sensor successfully detected the RF radiation over 5 m distance in the system demonstration. Experiments on two-dimensional (2D) stretching up to 15%, folding and twisting of the demonstrated sensor were also carried out. Despite the integrated device was severely deformed, no failure in RF radiation sensing was observed in the tests. This technique illuminates a promising route of realizing stretchable and foldable large area integrated RF electronics that are of great interest to a variety of applications like wearable computing, health monitoring, medical diagnostics, and curvilinear electronics.

Mutations in eukaryotic release factors 1 and 3 act as general nonsense suppressors in Drosophila.

PubMed Central

Chao, Anna T; Dierick, Herman A; Addy, Tracie M; Bejsovec, Amy

2003-01-01

In a screen for suppressors of the Drosophila wingless(PE4) nonsense allele, we isolated mutations in the two components that form eukaryotic release factor. eRF1 and eRF3 comprise the translation termination complex that recognizes stop codons and catalyzes the release of nascent polypeptide chains from ribosomes. Mutations disrupting the Drosophila eRF1 and eRF3 show a strong maternal-effect nonsense suppression due to readthrough of stop codons and are zygotically lethal during larval stages. We tested nonsense mutations in wg and in other embryonically acting genes and found that different stop codons can be suppressed but only a subset of nonsense alleles are subject to suppression. We suspect that the context of the stop codon is significant: nonsense alleles sensitive to suppression by eRF1 and eRF3 encode stop codons that are immediately followed by a cytidine. Such suppressible alleles appear to be intrinsically weak, with a low level of readthrough that is enhanced when translation termination is disrupted. Thus the eRF1 and eRF3 mutations provide a tool for identifying nonsense alleles that are leaky. Our findings have important implications for assigning null mutant phenotypes and for selecting appropriate alleles to use in suppressor screens. PMID:14573473

Around Marshall

NASA Image and Video Library

1963-01-14

At its founding, the Marshall Space Flight Center (MSFC) inherited the Army’s Jupiter and Redstone test stands, but much larger facilities were needed for the giant stages of the Saturn V. From 1960 to 1964, the existing stands were remodeled and a sizable new test area was developed. The new comprehensive test complex for propulsion and structural dynamics was unique within the nation and the free world, and they remain so today because they were constructed with foresight to meet the future as well as on going needs. Construction of the S-IC Static test stand complex began in 1961 in the west test area of MSFC, and was completed in 1964. The S-IC static test stand was designed to develop and test the 138-ft long and 33-ft diameter Saturn V S-IC first stage, or booster stage, weighing in at 280,000 pounds. Required to hold down the brute force of a 7,500,000-pound thrust produced by 5 F-1 engines, the S-IC static test stand was designed and constructed with the strength of hundreds of tons of steel and 12,000,000 pounds of cement, planted down to bedrock 40 feet below ground level. The foundation walls, constructed with concrete and steel, are 4 feet thick. The base structure consists of four towers with 40-foot-thick walls extending upward 144 feet above ground level. The structure was topped by a crane with a 135-foot boom. With the boom in the upright position, the stand was given an overall height of 405 feet, placing it among the highest structures in Alabama at the time. In addition to the S-IC test stand, related facilities were constructed during this time frame. Built just north of the massive S-IC test stand was the F-1 Engine test stand. The F-1 test stand is a vertical engine firing test stand, 239 feet in elevation and 4,600 square feet in area at the base, and was designed to assist in the development of the F-1 Engine. Capability was provided for static firing of 1.5 million pounds of thrust using liquid oxygen and kerosene. Like the S-IC stand, the foundation of the F-1 stand is keyed into the bedrock approximately 40 feet below grade. This photo, taken January 14, 1963 depicts the F-1 test stand site with hoses pumping excess water from the site.

1. CAPTIVE TEST STAND D1 FROM THE FERROCEMENT APRON, VIEW ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. CAPTIVE TEST STAND D-1 FROM THE FERROCEMENT APRON, VIEW TOWARDS SOUTHEAST. - Glenn L. Martin Company, Titan Missile Test Facilities, Captive Test Stand D-1, Waterton Canyon Road & Colorado Highway 121, Lakewood, Jefferson County, CO

2. CLOSE UP OF CAPTIVE TEST STAND D4, VIEW TOWARDS ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. CLOSE UP OF CAPTIVE TEST STAND D-4, VIEW TOWARDS NORTHEAST. - Glenn L. Martin Company, Titan Missile Test Facilities, Captive Test Stand D-4, Waterton Canyon Road & Colorado Highway 121, Lakewood, Jefferson County, CO

1. CAPTIVE TEST STAND D4, CONNECTING TUNNELS AT RIGHT, VIEW ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. CAPTIVE TEST STAND D-4, CONNECTING TUNNELS AT RIGHT, VIEW TOWARDS NORTHEAST. - Glenn L. Martin Company, Titan Missile Test Facilities, Captive Test Stand D-4, Waterton Canyon Road & Colorado Highway 121, Lakewood, Jefferson County, CO

51. HISTORIC GENERAL VIEW LOOKING WEST AT THE TEST STAND ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

51. HISTORIC GENERAL VIEW LOOKING WEST AT THE TEST STAND WITH THE MERCURY REDSTONE ROCKET FULLY ASSEMBLED AND BEING PREPARED FOR TESTING. - Marshall Space Flight Center, Redstone Rocket (Missile) Test Stand, Dodd Road, Huntsville, Madison County, AL

An introduction to testing techniques in the Intelsat TDMA/DSI system. II - Satellite system operations guide (SSOG) tests

NASA Astrophysics Data System (ADS)

Colby, R. J.; Parthasarathy, R.; Stimson, A. L.

1983-12-01

The test methods and procedures of the Intelsat TDMA/DSI SSOG are summarized. The overall structure of the SSOG is outlined, and the operational procedures to be followed for joining a new terminal to the system and for normal operations are reviewed, with an emphasis on the roles of the IOC and the TDMA reference and monitoring stations. The testing philosophy (based on minimal interruptions) and the star-test method are explained and illustrated with diagrams, and the test procedures are examined, including modem tests, electrical-path-length equalization, RF/IF downchain tests, protocol tests, nontransmitting protocol tests, IF/RF upchain tests, transmitting protocol tests, baseband tests, and orderwire lineups. The fundamental access discipline of the TDMA system is presented in an appendix.

Around Marshall

NASA Image and Video Library

1963-11-20

At its founding, the Marshall Space Flight Center (MSFC) inherited the Army’s Jupiter and Redstone test stands, but much larger facilities were needed for the giant stages of the Saturn V. From 1960 to 1964, the existing stands were remodeled and a sizable new test area was developed. The new comprehensive test complex for propulsion and structural dynamics was unique within the nation and the free world, and they remain so today because they were constructed with foresight to meet the future as well as on going needs. Construction of the S-IC Static test stand complex began in 1961 in the west test area of MSFC, and was completed in 1964. The S-IC static test stand was designed to develop and test the 138-ft long and 33-ft diameter Saturn V S-IC first stage, or booster stage, weighing in at 280,000 pounds. Required to hold down the brute force of a 7,500,000-pound thrust produced by 5 F-1 engines, the S-IC static test stand was designed and constructed with the strength of hundreds of tons of steel and 12,000,000 pounds of cement, planted down to bedrock 40 feet below ground level. The foundation walls, constructed with concrete and steel, are 4 feet thick. The base structure consists of four towers with 40-foot-thick walls extending upward 144 feet above ground level. The structure was topped by a crane with a 135-foot boom. With the boom in the upright position, the stand was given an overall height of 405 feet, placing it among the highest structures in Alabama at the time. North of the massive S-IC test stand, the F-1 Engine test stand was built. Designed to assist in the development of the F-1 Engine, the F-1 test stand is a vertical engine firing test stand, 239 feet in elevation and 4,600 square feet in area at the base. Capability was provided for static firing of 1.5 million pounds of thrust using liquid oxygen and kerosene. Like the S-IC stand, the foundation of the F-1 stand is keyed into the bedrock approximately 40 feet below grade. This photo shows the progress of the F-1 Test Stand as of November 20, 1963.

Around Marshall

NASA Image and Video Library

1963-04-04

At its founding, the Marshall Space Flight Center (MSFC) inherited the Army’s Jupiter and Redstone test stands, but much larger facilities were needed for the giant stages of the Saturn V. From 1960 to 1964, the existing stands were remodeled and a sizable new test area was developed. The new comprehensive test complex for propulsion and structural dynamics was unique within the nation and the free world, and they remain so today because they were constructed with foresight to meet the future as well as on going needs. Construction of the S-IC Static test stand complex began in 1961 in the west test area of MSFC, and was completed in 1964. The S-IC static test stand was designed to develop and test the 138-ft long and 33-ft diameter Saturn V S-IC first stage, or booster stage, weighing in at 280,000 pounds. Required to hold down the brute force of a 7,500,000-pound thrust produced by 5 F-1 engines, the S-IC static test stand was designed and constructed with the strength of hundreds of tons of steel and 12,000,000 pounds of cement, planted down to bedrock 40 feet below ground level. The foundation walls, constructed with concrete and steel, are 4 feet thick. The base structure consists of four towers with 40-foot-thick walls extending upward 144 feet above ground level. The structure was topped by a crane with a 135-foot boom. With the boom in the upright position, the stand was given an overall height of 405 feet, placing it among the highest structures in Alabama at the time. North of the massive S-IC test stand, the F-1 Engine test stand was built. Designed to assist in the development of the F-1 Engine, the F-1 test stand is a vertical engine firing test stand, 239 feet in elevation and 4,600 square feet in area at the base. Capability was provided for static firing of 1.5 million pounds of thrust using liquid oxygen and kerosene. Like the S-IC stand, the foundation of the F-1 stand is keyed into the bedrock approximately 40 feet below grade. This photo, taken April 4, 1963 depicts the construction of the F-1 test stand foundation walls.

Around Marshall

NASA Image and Video Library

1963-04-17

At its founding, the Marshall Space Flight Center (MSFC) inherited the Army’s Jupiter and Redstone test stands, but much larger facilities were needed for the giant stages of the Saturn V. From 1960 to 1964, the existing stands were remodeled and a sizable new test area was developed. The new comprehensive test complex for propulsion and structural dynamics was unique within the nation and the free world, and they remain so today because they were constructed with foresight to meet the future as well as on going needs. Construction of the S-IC Static test stand complex began in 1961 in the west test area of MSFC, and was completed in 1964. The S-IC static test stand was designed to develop and test the 138-ft long and 33-ft diameter Saturn V S-IC first stage, or booster stage, weighing in at 280,000 pounds. Required to hold down the brute force of a 7,500,000-pound thrust produced by 5 F-1 engines, the S-IC static test stand was designed and constructed with the strength of hundreds of tons of steel and 12,000,000 pounds of cement, planted down to bedrock 40 feet below ground level. The foundation walls, constructed with concrete and steel, are 4 feet thick. The base structure consists of four towers with 40-foot-thick walls extending upward 144 feet above ground level. The structure was topped by a crane with a 135-foot boom. With the boom in the upright position, the stand was given an overall height of 405 feet, placing it among the highest structures in Alabama at the time. North of the massive S-IC test stand, the F-1 Engine test stand was built. Designed to assist in the development of the F-1 Engine, the F-1 test stand is a vertical engine firing test stand, 239 feet in elevation and 4,600 square feet in area at the base. Capability was provided for static firing of 1.5 million pounds of thrust using liquid oxygen and kerosene. Like the S-IC stand, the foundation of the F-1 stand is keyed into the bedrock approximately 40 feet below grade. This photo, taken April 17, 1963 depicts the construction of the F-1 test stand foundation walls.

Credit BG. Test Stand "D" tower as seen looking northeast ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Credit BG. Test Stand "D" tower as seen looking northeast (See caption for CA-163-F-18). To the right of the view is the stainless steel dome top for Dv Cell (see CA-163-F-22 for view into cell), behind which rests a spherical accumulator--an electrically heated steam generator for powering the vacuum system at "C" and Test Stand "D." Part of the ejector system can be seen on the right corner of the tower, other connections include electrical ducts (thin, flat metal members) and fire protection systems. Note the stand in the foreground with lights used to indicate safety status of the stand during tests - Jet Propulsion Laboratory Edwards Facility, Test Stand D, Edwards Air Force Base, Boron, Kern County, CA

ROBERT BOBO AND MIKE NICHOLS AT TEST STAND 4693

NASA Image and Video Library

2016-12-14

ROBERT BOBO, LEFT, AND MIKE NICHOLS TALK BENEATH THE 221-FOOT-TALL TEST STAND 4693, THE LARGEST OF TWO NEW SPACE LAUNCH SYSTEM TEST STANDS AT MSFC. BOBO MANAGES SLS STRUCTURAL STRENGTH TESTING, AND NICHOLS IS LEAD TEST ENGINEER FOR THE SLS LIQUID HYDROGEN TANK.

22. DETAIL, TWO LIGHTING TYPES AT REAR OF TEST STAND ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

22. DETAIL, TWO LIGHTING TYPES AT REAR OF TEST STAND 1-A. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-A, Test Area 1-120, north end of Jupiter Boulevard, Boron, Kern County, CA

Around Marshall

NASA Image and Video Library

1963-08-13

At its founding, the Marshall Space Flight Center (MSFC) inherited the Army’s Jupiter and Redstone test stands, but much larger facilities were needed for the giant stages of the Saturn V. From 1960 to 1964, the existing stands were remodeled and a sizable new test area was developed. The new comprehensive test complex for propulsion and structural dynamics was unique within the nation and the free world, and they remain so today because they were constructed with foresight to meet the future as well as on going needs. Construction of the S-IC Static test stand complex began in 1961 in the west test area of MSFC, and was completed in 1964. The S-IC static test stand was designed to develop and test the 138-ft long and 33-ft diameter Saturn V S-IC first stage, or booster stage, weighing in at 280,000 pounds. Required to hold down the brute force of a 7,500,000-pound thrust produced by 5 F-1 engines, the S-IC static test stand was designed and constructed with the strength of hundreds of tons of steel and 12,000,000 pounds of cement, planted down to bedrock 40 feet below ground level. The foundation walls, constructed with concrete and steel, are 4 feet thick. The base structure consists of four towers with 40-foot-thick walls extending upward 144 feet above ground level. The structure was topped by a crane with a 135-foot boom. With the boom in the upright position, the stand was given an overall height of 405 feet, placing it among the highest structures in Alabama at the time. In addition to the stand itself, related facilities were constructed during this time. North of the massive S-IC test stand, the F-1 Engine test stand was built. Designed to assist in the development of the F-1 Engine, the F-1 test stand is a vertical engine firing test stand, 239 feet in elevation and 4,600 square feet in area at the base. Capability was provided for static firing of 1.5 million pounds of thrust using liquid oxygen and kerosene. Like the S-IC stand, the foundation of the F-1 stand is keyed into the bedrock approximately 40 feet below grade. This photo depicts the construction of the F-1 test stand as of August 13, 1963. All four of its tower legs are well underway into the skyline.

rf breakdown measurements in electron beam driven 200 GHz copper and copper-silver accelerating structures

DOE PAGES

Dal Forno, Massimo; Dolgashev, Valery; Bowden, Gordon; ...

2016-11-30

This study explores the physics of vacuum rf breakdowns in subterahertz high-gradient traveling-wave accelerating structures. We present the experimental results of rf tests of 200 GHz metallic accelerating structures, made of copper and copper-silver. These experiments were carried out at the Facility for Advanced Accelerator Experimental Tests (FACET) at the SLAC National Accelerator Laboratory. The rf fields were excited by the FACET ultrarelativistic electron beam. The traveling-wave structure is an open geometry, 10 cm long, composed of two halves separated by a gap. The rf frequency of the fundamental accelerating mode depends on the gap size and can be changedmore » from 160 to 235 GHz. When the beam travels off axis, a deflecting field is induced in addition to the longitudinal field. We measure the deflecting forces by observing the displacement of the electron bunch and use this measurement to verify the expected accelerating gradient. Furthermore, we present the first quantitative measurement of rf breakdown rates in 200 GHz metallic accelerating structures. The breakdown rate of the copper structure is 10 –2 per pulse, with a peak surface electric field of 500 MV/m and a rf pulse length of 0.3 ns, which at a relatively large gap of 1.5 mm, or one wavelength, corresponds to an accelerating gradient of 56 MV/m. For the same breakdown rate, the copper-silver structure has a peak electric field of 320 MV/m at a pulse length of 0.5 ns. For a gap of 1.1 mm, or 0.74 wavelengths, this corresponds to an accelerating gradient of 50 MV/m.« less

IgA rheumatoid factor as a serological predictor of poor response to tumour necrosis factor α inhibitors in rheumatoid arthritis.

PubMed

Sakthiswary, Rajalingham; Shaharir, Syahrul S; Mohd Said, Mohd S; Asrul, Abdul W; Shahril, Nor S

2014-11-01

The main objective of this study is to elucidate the role of immunoglobulin A (IgA) rheumatoid factor (RF) in predicting the clinical response to tumour necrosis factor α inhibitors (TNFi) among patients with rheumatoid arthritis (RA). We recruited all patients with RA who were ever on TNFi for a minimum duration of 3 months at our centre. Based on the European League Against Rheumatism response criteria, subjects were further divided into responders and non-responders. Age-matched RA patients who were on conventional disease-modifying anti-rheumatic drugs and in remission were enrolled as controls. Subjects were tested for quantitative values of IgA, IgM, IgG RF and anti-citrulinated cyclic peptides (CCP). Further, all subjects were assessed for the disease activity score that includes 28 joints (DAS28) and Stanford Health Assessment Questionnaire (HAQ) 8-item Disability Index (HAQ-DI). A total of 31 subjects with RA who had received TNFi and 15 controls were enrolled in this study. There was a trend for the non-responders (n = 10) to have higher levels of all isotypes of RF and anti-CCP. However, only the IgA RF and anti-CCP levels were significantly higher in the non-responder group compared to the responders and controls (P = 0.001, P = 0.034, respectively). On multivariate analysis, only the IgA RF remained significant (OR 0.989; 95% CI 0.980-0.999; P = 0.026). IgA RF is potentially a novel predictor of response to TNFi in RA patients. Testing for pretreatment IgA RF levels could be a reasonable consideration before commencement of TNFi. © 2014 Asia Pacific League of Associations for Rheumatology and Wiley Publishing Asia Pty Ltd.

Radiofrequency in female external genital cosmetics and sexual function: a randomized clinical trial.

PubMed

Lordêlo, Patrícia; Leal, Mariana Robatto Dantas; Brasil, Cristina Aires; Santos, Juliana Menezes; Lima, Maria Clara Neves Pavie Cardoso; Sartori, Marair Gracio Ferreira

2016-11-01

Female sexual behavior goes through cultural changes constantly, and recently, some women have shown the desire the ideal genitalia. In this study, we aimed to evaluate clinical responses to nonablative radiofrequency (RF) in terms of its cosmetic outcome in the female external genitalia and its effect on sexual function. A single-masking randomized controlled trial was conducted in 43 women (29 sexually active) who were unsatisfied with the appearance of their external genitalia. The women were divided into an RF group (n = 21, 14 sexually active) and a control group (n = 22, 15 sexually active). Eight sessions of RF were performed once a week. Photographs (taken before the first session and 8 days after the last session) were evaluated by the women and three blinded health professionals by using two 3-point Likert scales (unsatisfied, unchanged, and satisfied; and worst, unchanged, and improved). Sexual function was evaluated using the Female Sexual Function Index (FSFI) and analyzed using the Student t test. Women's satisfaction and health professional evaluation were analyzed using the chi-square test and inter- and intragroup binomial comparisons. Satisfaction response rates were 76 and 27 % for the RF and control groups, respectively (p = 0.001). All professionals found a clinical improvement association in the treated group with RF in comparison with the control group (p < 0.01). The overall FSFI sexual function score increased by 3.51 points in the RF group vs 0.1 points in the control group (p = 0.003). RF is an alternative for attaining a cosmetic outcome for the female external genitalia, with positives changes in patients' satisfaction and FSFI scores.

Antiviral screening of forty-two Egyptian medicinal plants.

PubMed

Soltan, Maha Mohamed; Zaki, Adel Kamal

2009-10-29

Egyptian medicinal plants are well known by their diverse uses in traditional folk medicine to cure various ailments including infectious diseases. Forty-two Egyptian medicinal plant species were selected from local market and were subjected to antiviral screening bioassay to investigate and to evaluate their biological activities. Hydro-alcoholic extracts of each species were separately prepared and tested against three viruses: herpes simplex-1 virus (HSV), poliomyelitis-1 virus (POLIO) and vesicular stomatitis virus (VSV). The antiviral activity were determined by means of the end point titration technique (EPTT) that depends on the ability of plant extract dilutions to inhibit the produced cytopathogenic effect (CPE) and expressed as reduction factor (Rf) of the viral titer. Achillea fragrantissima, Jasonia montana and Globularia arabica are found to have antiviral activity against POLIO in a concentration dependent manner at complete non-toxic concentration range 10-100 microg/ml (Rf 10(6)), 10-100 microg/ml (Rf 10(5)) and 50-100 microg/ml (Rf 10(4)), respectively while Tanacetum sinaicum are found to have moderate antiviral activity against POLIO at concentration of 50-100 microg/ml (Rf 10(2)). Ephedra alata and Moringa peregrina are found to have antiviral activity against HSV (Rf 10(4)). Also, the results revealed that Capparis sinaica, Tamarix nilotica and Cyperus rotundus are found to have virucidal effect against HSV. All the forty-two plant species are found to have no reliable antiviral activity against VSV. The specific indications claimed by the traditional healers are confirmed by antiviral test.

Credit BG. View looking southwest at Test Stand "D" complex. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Credit BG. View looking southwest at Test Stand "D" complex. In the background at left is the Steam Generator Plant 4280/E-81 built in 1972 to house four gas-fired Clayton flash boilers. The boilers were later supplemented by the electrically heated steam accumulator (sphere) to supply steam to the various ejectors at Test Stand "D" vacuum test cells - Jet Propulsion Laboratory Edwards Facility, Test Stand D, Edwards Air Force Base, Boron, Kern County, CA

1950 MHz radiofrequency electromagnetic fields do not aggravate memory deficits in 5xFAD mice.

PubMed

Son, Yeonghoon; Jeong, Ye Ji; Kwon, Jong Hwa; Choi, Hyung-Do; Pack, Jeong-Ki; Kim, Nam; Lee, Yun-Sil; Lee, Hae-June

2016-09-01

The increased use of mobile phones has generated public concern about the impact of radiofrequency electromagnetic fields (RF-EMF) on health. In the present study, we investigated whether RF-EMFs induce molecular changes in amyloid precursor protein (APP) processing and amyloid beta (Aβ)-related memory impairment in the 5xFAD mouse, which is a widely used amyloid animal model. The 5xFAD mice at the age of 1.5 months were assigned to two groups (RF-EMF- and sham-exposed groups, eight mice per group). The RF-EMF group was placed in a reverberation chamber and exposed to 1950 MHz electromagnetic fields for 3 months (SAR 5 W/kg, 2 h/day, 5 days/week). The Y-maze, Morris water maze, and novel object recognition memory test were used to evaluate spatial and non-spatial memory following 3-month RF-EMF exposure. Furthermore, Aβ deposition and APP and carboxyl-terminal fragment β (CTFβ) levels were evaluated in the hippocampus and cortex of 5xFAD mice, and plasma levels of Aβ peptides were also investigated. In behavioral tests, mice that were exposed to RF-EMF for 3 months did not exhibit differences in spatial and non-spatial memory compared to the sham-exposed group, and no apparent change was evident in locomotor activity. Consistent with behavioral data, RF-EMF did not alter APP and CTFβ levels or Aβ deposition in the brains of the 5xFAD mice. These findings indicate that 3-month RF-EMF exposure did not affect Aβ-related memory impairment or Aβ accumulation in the 5xFAD Alzheimer's disease model. Bioelectromagnetics. 37:391-399, 2016. © 2016 The Authors Bioelectromagnetics published by Wiley Periodicals, Inc. on behalf of Bioelectromagnetics Society. © 2016 The Authors Bioelectromagnetics published by Wiley Periodicals, Inc. on behalf of Bioelectromagnetics Society.

Improved RF Measurements of SRF Cavity Quality Factors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holzbauer, J. P.; Contreras, C.; Pischalnikov, Y.

SRF cavity quality factors can be accurately measured using RF-power based techniques only when the cavity is very close to critically coupled. This limitation is from systematic errors driven by non-ideal RF components. When the cavity is not close to critically coupled, these systematic effects limit the accuracy of the measurements. The combination of the complex base-band envelopes of the cavity RF signals in combination with a trombone in the circuit allow the relative calibration of the RF signals to be extracted from the data and systematic effects to be characterized and suppressed. The improved calibration allows accurate measurements tomore » be made over a much wider range of couplings. Demonstration of these techniques during testing of a single-spoke resonator with a coupling factor of near 7 will be presented, along with recommendations for application of these techniques.« less

Sedentary lifestyle in individuals with hypertension.

PubMed

Martins, Larissa Castelo Guedes; Lopes, Marcos Venícios de Oliveira; Guedes, Nirla Gomes; Nunes, Marília Mendes; Diniz, Camila Maciel; Carvalho, Priscilla Magalhães de Oliveira

2015-01-01

to identify the prevalence of nursing diagnosis Sedentary lifestyle (SL) and to analyze its association with clinical indicators (CI) and related factors (RF) in patients with hypertension. cross-sectional study with 285 patients with hypertension at a reference center for outpatient care in Northeastern Brazil. To collect data it was used an instrument based on operational defi nitions of the CI and RF previously validated. Four nurses rated SL as present or absent. To evaluate the association between CI and RF with the presence of SL it was applied the chi-square test. The prevalence ratio and confi dence interval was calculated to verify the magnitude of the effect between RF and SL. SL was identifi ed in 55.8% of the sample. Five IC and six RF showed a signifi cant association with SL. the study identifi es main indicators for inference of SL as well as their possible causal factors among people with hypertension.

Bioassay for assessing cell stress in the vicinity of radio-frequency irradiating antennas.

PubMed

Monselise, Edna Ben-Izhak; Levkovitz, Aliza; Gottlieb, Hugo E; Kost, Daniel

2011-07-01

The 24 h exposure of water plants (etiolated duckweed) to RF-EMF between 7.8 V m(-1) and 1.8 V m(-1), generated by AM 1.287 MHz transmitting antennas, resulted in alanine accumulation in the plant cells, a phenomenon we have previously shown to be a universal stress signal. The magnitude of the effect corresponds qualitatively to the level of RF-EMF exposure. In the presence of 10 mM vitamin C, alanine accumulation is completely suppressed, suggesting the involvement of free radicals in the process. A unique biological connection has thus been made between exposure to RF-EMF and cell stress, in the vicinity of RF transmitting antennas. This simple test, which lasts only 24 h, constitutes a useful bioassay for the quick detection of biological cell stress caused in the vicinity of RF irradiating antennas.

9. BUILDING 8769, EAST REAR AND NORTH SIDE, TEST STAND ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

9. BUILDING 8769, EAST REAR AND NORTH SIDE, TEST STAND AT RIGHT. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Observation Bunkers for Test Stand 1-A, Test Area 1-120, north end of Jupiter Boulevard, Boron, Kern County, CA

3. EAST SIDE, ALSO SHOWING COVERED TANKS AND TEST STAND ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

3. EAST SIDE, ALSO SHOWING COVERED TANKS AND TEST STAND 1-5 AT RIGHT. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-4, Test Area 1-115, northwest end of Saturn Boulevard, Boron, Kern County, CA

Association of unipedal standing time and bone mineral density in community-dwelling Japanese women.

PubMed

Sakai, A; Toba, N; Takeda, M; Suzuki, M; Abe, Y; Aoyagi, K; Nakamura, T

2009-05-01

Bone mineral density (BMD) and physical performance of the lower extremities decrease with age. In community-dwelling Japanese women, unipedal standing time, timed up and go test, and age are associated with BMD while in women aged 70 years and over, unipedal standing time is associated with BMD. The aim of this study was to clarify whether unipedal standing time is significantly associated with BMD in community-dwelling women. The subjects were 90 community-dwelling Japanese women aged 54.7 years. BMD of the second metacarpal bone was measured by computed X-ray densitometry. We measured unipedal standing time as well as timed up and go test to assess physical performance of the lower extremities. Unipedal standing time decreased with increased age. Timed up and go test significantly correlated with age. Low BMD was significantly associated with old age, short unipedal standing time, and long timed up and go test. Stepwise regression analysis revealed that age, unipedal standing time, and timed up and go test were significant factors associated with BMD. In 21 participants aged 70 years and over, body weight and unipedal standing time, but not age, were significantly associated with BMD. BMD and physical performance of the lower extremities decrease with older age. Unipedal standing time, timed up and go test, and age are associated with BMD in community-dwelling Japanese women. In women aged 70 years and over, unipedal standing time is significantly associated with BMD.

A noncontact RF-based respiratory sensor: results of a clinical trial.

PubMed

Madsen, Spence; Baczuk, Jordan; Thorup, Kurt; Barton, Richard; Patwari, Neal; Langell, John T

2016-06-01

Respiratory rate (RR) is a critical vital signs monitored in health care setting. Current monitors suffer from sensor-contact failure, inaccurate data, and limited patient mobility. There is a critical need for an accurate and reliable and noncontact system to monitor RR. We developed a contact-free radio frequency (RF)-based system that measures movement using WiFi signal diffraction, which is converted into interpretable data using a Fourier transform. Here, we investigate the system's ability to measure fine movements associated with human respiration. Testing was conducted on subjects using visual cue, fixed-tempo instruction to breath at standard RRs. Blinded instruction-based RRs were compared to RF-acquired data to determine measurement accuracy. The RF-based technology was studied on postoperative ventilator-dependent patients. Blinded ventilator capnographic RR data were collected for each patient and compared to RF-acquired data to determine measurement accuracy. Respiratory rate data collected from 10 subjects breathing at a fixed RR (14, 16, 18, or 20) demonstrated 95.5% measurement accuracy between the patient's actual rate and that measured by our RF technology. Ten patients were enrolled into the clinical trial. Blinded ventilator capnographic RR data were compared to RF-based acquired data. The RF-based data showed 88.8% measurement accuracy with ventilator capnography. Initial clinical pilot trials with our contact-free RF-based monitoring system demonstrate a high degree of RR measurement accuracy when compared to capnographic data. Based on these results, we believe RF-based systems present a promising noninvasive, inexpensive, and accurate tool for continuous RR monitoring. Copyright © 2016 Elsevier Inc. All rights reserved.

Knee implant imaging at 3 Tesla using high-bandwidth radiofrequency pulses.

PubMed

Bachschmidt, Theresa J; Sutter, Reto; Jakob, Peter M; Pfirrmann, Christian W A; Nittka, Mathias

2015-06-01

To investigate the impact of high-bandwidth radiofrequency (RF) pulses used in turbo spin echo (TSE) sequences or combined with slice encoding for metal artifact correction (SEMAC) on artifact reduction at 3 Tesla in the knee in the presence of metal. Local transmit/receive coils feature increased maximum B1 amplitude, reduced SAR exposition and thus enable the application of high-bandwidth RF pulses. Susceptibility-induced through-plane distortion scales inversely with the RF bandwidth and the view angle, hence blurring, increases for higher RF bandwidths, when SEMAC is used. These effects were assessed for a phantom containing a total knee arthroplasty. TSE and SEMAC sequences with conventional and high RF bandwidths and different contrasts were tested on eight patients with different types of implants. To realize scan times of 7 to 9 min, SEMAC was always applied with eight slice-encoding steps and distortion was rated by two radiologists. A local transmit/receive knee coil enables the use of an RF bandwidth of 4 kHz compared with 850 Hz in conventional sequences. Phantom scans confirm the relation of RF bandwidth and through-plane distortion, which can be reduced up to 79%, and demonstrate the increased blurring for high-bandwidth RF pulses. In average, artifacts in this RF mode are rated hardly visible for patients with joint arthroplasties, when eight SEMAC slice-encoding steps are applied, and for patients with titanium fixtures, when TSE is used. The application of high-bandwidth RF pulses by local transmit coils substantially reduces through-plane distortion artifacts at 3 Tesla. © 2014 Wiley Periodicals, Inc.

2. Credit JPL. Photographic copy of photograph, looking northeast at ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. Credit JPL. Photographic copy of photograph, looking northeast at unfinished original Test Stand 'C' construction. A portion of the corrugated steel tunnel tube connecting Test Stand 'C' to the first phase of JPL tunnel system construction is visible in the foreground. The steel frame used to support propellant tanks and engine equipment has been erected. The open trap door leads to a chamber inside the Test Stand 'C' base where gaseous nitrogen is distributed via manifolds to Test Stand 'C' control valves. (JPL negative no. 384-1568-A, 19 March 1957) - Jet Propulsion Laboratory Edwards Facility, Test Stand C, Edwards Air Force Base, Boron, Kern County, CA

Measurement properties and feasibility of clinical tests to assess sit-to-stand/stand-to-sit tasks in subjects with neurological disease: a systematic review

PubMed Central

Silva, Paula F. S.; Quintino, Ludmylla F.; Franco, Juliane; Faria, Christina D. C. M.

2014-01-01

Background Subjects with neurological disease (ND) usually show impaired performance during sit-to-stand and stand-to-sit tasks, with a consequent reduction in their mobility levels. Objective To determine the measurement properties and feasibility previously investigated for clinical tests that evaluate sit-to-stand and stand-to-sit in subjects with ND. Method A systematic literature review following the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) protocol was performed. Systematic literature searches of databases (MEDLINE/SCIELO/LILACS/PEDro) were performed to identify relevant studies. In all studies, the following inclusion criteria were assessed: investigation of any measurement property or the feasibility of clinical tests that evaluate sit-to-stand and stand-to-sit tasks in subjects with ND published in any language through December 2012. The COSMIN checklist was used to evaluate the methodological quality of the included studies. Results Eleven studies were included. The measurement properties/feasibility were most commonly investigated for the five-repetition sit-to-stand test, which showed good test-retest reliability (Intraclass Correlation Coefficient:ICC=0.94-0.99) for subjects with stroke, cerebral palsy and dementia. The ICC values were higher for this test than for the number of repetitions in the 30-s test. The five-repetition sit-to-stand test also showed good inter/intra-rater reliabilities (ICC=0.97-0.99) for stroke and inter-rater reliability (ICC=0.99) for subjects with Parkinson disease and incomplete spinal cord injury. For this test, the criterion-related validity for subjects with stroke, cerebral palsy and incomplete spinal cord injury was, in general, moderate (correlation=0.40-0.77), and the feasibility and safety were good for subjects with Alzheimer's disease. Conclusions The five-repetition sit-to-stand test was used more often in subjects with ND, and most of the measurement properties were investigated and showed adequate results. PMID:24839043

Random Forests for Global and Regional Crop Yield Predictions.

PubMed

Jeong, Jig Han; Resop, Jonathan P; Mueller, Nathaniel D; Fleisher, David H; Yun, Kyungdahm; Butler, Ethan E; Timlin, Dennis J; Shim, Kyo-Moon; Gerber, James S; Reddy, Vangimalla R; Kim, Soo-Hyung

2016-01-01

Accurate predictions of crop yield are critical for developing effective agricultural and food policies at the regional and global scales. We evaluated a machine-learning method, Random Forests (RF), for its ability to predict crop yield responses to climate and biophysical variables at global and regional scales in wheat, maize, and potato in comparison with multiple linear regressions (MLR) serving as a benchmark. We used crop yield data from various sources and regions for model training and testing: 1) gridded global wheat grain yield, 2) maize grain yield from US counties over thirty years, and 3) potato tuber and maize silage yield from the northeastern seaboard region. RF was found highly capable of predicting crop yields and outperformed MLR benchmarks in all performance statistics that were compared. For example, the root mean square errors (RMSE) ranged between 6 and 14% of the average observed yield with RF models in all test cases whereas these values ranged from 14% to 49% for MLR models. Our results show that RF is an effective and versatile machine-learning method for crop yield predictions at regional and global scales for its high accuracy and precision, ease of use, and utility in data analysis. RF may result in a loss of accuracy when predicting the extreme ends or responses beyond the boundaries of the training data.

Last SSME test on A-1

NASA Image and Video Library

2006-09-29

The Stennis Space Center conducted the final space shuttle main engine test on its A-1 Test Stand Friday. The A-1 Test Stand was the site of the first test on a shuttle main engine in 1975. Stennis will continue testing shuttle main engines on its A-2 Test Stand through the end of the Space Shuttle Program in 2010. The A-1 stand begins a new chapter in its operational history in October. It will be temporarily decommissioned to convert it for testing the J-2X engine, which will power the upper stage of NASA's new crew launch vehicle, the Ares I. Although this ends the stand's work on the Space Shuttle Program, it will soon be used for the rocket that will carry America's next generation human spacecraft, Orion.

45. HISTORIC AERIAL VIEW LOOKING SOUTHWEST AT THE TEST STAND ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

45. HISTORIC AERIAL VIEW LOOKING SOUTHWEST AT THE TEST STAND AND THE SURROUNDING ELECTRONICS AND EQUIPMENT TRAILERS. - Marshall Space Flight Center, Redstone Rocket (Missile) Test Stand, Dodd Road, Huntsville, Madison County, AL

Impact of catheter ablation with remote magnetic navigation on procedural outcomes in patients with persistent and long-standing persistent atrial fibrillation.

PubMed

Jin, Qi; Pehrson, Steen; Jacobsen, Peter Karl; Chen, Xu

2015-11-01

The objectives of this study were to assess the procedural outcomes of persistent and long-standing persistent atrial fibrillation (PsAF and L-PsAF) ablation guided by remote magnetic navigation (RMN), and to detect factors predicting acute restoration of sinus rhythm (SR) by ablation with RMN. A total of 313 patients (275 male, age 59 ± 9.5 years) with PsAF (187/313) or L-PsAF (126/313) undergoing ablation using RMN were included. Patients' disease history, pulmonary venous anatomy, left atrial (LA) volume, procedure time, mapping plus ablation time, radiofrequency (RF) ablation time, fluoroscopy time, radiation dose, and complications were assessed. Stepwise regression was used to predict which variable could best predict acute restoration from AF to SR by ablation. Compared to PsAF, procedure time and RF ablation time were significantly increased in patients with L-PsAF (P = 0.01 and P < 0.001, respectively). No major complications occurred during the procedures in either PsAF or L-PsAF patients. Fifty five of 313 patients converted directly to SR by ablation. Compared to L-PsAF, the rate of SR restoration was significantly higher in PsAF (21 vs 12%, P = 0.03). Stepwise regression analysis showed LA volume was the primary parameter affecting SR restoration (P = 0.01). The LA volume of patients without direct SR restoration by ablation was 24% greater than that of patients with SR restoration (P < 0.001). Catheter ablation using RMN is a safe and effective method for PsAF and L-PsAF. LA volume could be a predictor of direct restoration of SR from sustaining AF by ablation using RMN.

Observation of the standing wave effect in large-area, very-high-frequency capacitively coupled plasmas by using a fiber Bragg grating sensor

NASA Astrophysics Data System (ADS)

Han, Dao-Man; Liu, Yong-Xin; Gao, Fei; Wang, Xiang-Yu; Li, Ang; Xu, Jun; Jing, Zhen-Guo; Wang, You-Nian

2018-06-01

The large-area capacitive discharges driven at very high frequencies have been attracting much attention due to their wide applications in material etching and thin film deposition. However, in the regime, the standing wave effect (SWE) becomes a major limitation for plasma material processing uniformity. In this work, a fiber Bragg grating sensor was utilized for the observation of the SWE in a large-area capacitive discharge reactor by measuring the radial distribution of the neutral gas temperature T g. The influences of the RF power and the working pressure on the radial profiles of T g were studied. At a higher frequency (100 MHz) and a lower pressure (5 Pa), T g presents a center-peaked radial distribution, indicating a significant SWE. As the RF power increases, the central peak of T g becomes more evident due to the enhanced SWE. By contrast, at 100 MHz and a higher pressure (40 Pa), the radial distribution of T g shows an evident peak at the electrode edge and T g decays dramatically towards the discharge center because the electromagnetic waves are strongly damped as they are propagating from the edge to the center. At a lower frequency (27 MHz), only edge-high profiles of T g are observed for various pressures. For the sake of a comparison, a hairpin resonance probe was used to measure the radial distributions of the plasma density n p under the same condition. The radial profiles of T g are found to generally resemble those of n p under various conditions. Based on the experimental results, the neutral gas heating mechanism was analyzed.

Construction Progress of the S-IC Test Stand Complex Bunker House

NASA Technical Reports Server (NTRS)

1963-01-01

At its founding, the Marshall Space Flight Center (MSFC) inherited the Army's Jupiter and Redstone test stands, but much larger facilities were needed for the giant stages of the Saturn V. From 1960 to 1964, the existing stands were remodeled and a sizable new test area was developed. The new comprehensive test complex for propulsion and structural dynamics was unique within the nation and the free world, and they remain so today because they were constructed with foresight to meet the future as well as on going needs. Construction of the S-IC Static test stand complex began in 1961 in the west test area of MSFC, and was completed in 1964. The S-IC static test stand was designed to develop and test the 138-ft long and 33-ft diameter Saturn V S-IC first stage, or booster stage, weighing in at 280,000 pounds. Required to hold down the brute force of a 7,500,000-pound thrust produced by 5 F-1 engines, the S-IC static test stand was designed and constructed with the strength of hundreds of tons of steel and 12,000,000 pounds of cement, planted down to bedrock 40 feet below ground level. The foundation walls, constructed with concrete and steel, are 4 feet thick. The base structure consists of four towers with 40-foot-thick walls extending upward 144 feet above ground level. The structure was topped by a crane with a 135-foot boom. With the boom in the upright position, the stand was given an overall height of 405 feet, placing it among the highest structures in Alabama at the time. In addition to the S-IC stand, additional related facilities were built during this time frame. Built to the east of the S-IC stand, the block house served as the control room. To the south of the blockhouse was a newly constructed pump house used for delivering water to the S-IC stand during testing. North of the massive test stand, the F-1 Engine test stand was built for testing a single F-1 engine. Just southeast of the S-IC stand a concrete bunker house was constructed. The bunker housed an emergency crew clad in fire proof gear, who were close at hand should any emergencies arise during testing. This photo of the completed bunker house was taken on May 7, 1963.

A-3 Test Stand construction moves forward

NASA Image and Video Library

2010-07-13

Work on the A-3 Test Stand at Stennis Space Center took a step forward in July with delivery of the first-stage steam ejector July 13. Stennis employees are shown preparing the ejector to be lifted into place on the test stand. When activated in 2012, the A-3 Test Stand will allow operators to test rocket engines at simulated altitudes of 100,000 feet, a critical feature for next-generation engines that will take humans beyond low-Earth orbit once more.

5. BUILDING 8768, SOUTH SIDE AND EAST REAR. TEST STAND ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

5. BUILDING 8768, SOUTH SIDE AND EAST REAR. TEST STAND 1A AT LEFT. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Observation Bunkers for Test Stand 1-A, Test Area 1-120, north end of Jupiter Boulevard, Boron, Kern County, CA

21. Building 202, underside of test stand A, detail of ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

21. Building 202, underside of test stand A, detail of junction of scrubber structure and test stand with water pipes and valves visible. View looking southeast. - Rocket Engine Testing Facility, GRC Building No. 202, NASA Glenn Research Center, Cleveland, Cuyahoga County, OH

37. HISTORIC GENERAL VIEW LOOKING WEST OF TEST STAND AND ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

37. HISTORIC GENERAL VIEW LOOKING WEST OF TEST STAND AND ROCKET DURING TEST FIRING NUMBER 2. NOTE THE FLAME BEING EMITTED FROM THE BOTTOM OF THE ROCKET. - Marshall Space Flight Center, Redstone Rocket (Missile) Test Stand, Dodd Road, Huntsville, Madison County, AL

8. VIEW LOOKING WEST AT THE POWER PLANT TEST STAND ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

8. VIEW LOOKING WEST AT THE POWER PLANT TEST STAND DURING AN ENGINE FIRING. DATE UNKNOWN, FRED ORDWAY COLLECTION, U.S. SPACE AND ROCKET CENTER, HUNTSVILLE, AL. - Marshall Space Flight Center, East Test Area, Power Plant Test Stand, Huntsville, Madison County, AL

PAL-XFEL cavity beam position monitor pick-up design and beam test

NASA Astrophysics Data System (ADS)

Lee, Sojeong; Park, Young Jung; Kim, Changbum; Kim, Seung Hwan; Shin, Dong Cheol; Han, Jang-Hui; Ko, In Soo

2016-08-01

As an X-ray Free Electron Laser, PAL-XFEL is about to start beam commissioning. X-band cavity beam position monitor (BPM) is used in the PAL-XFEL undulator beam line. Prototypes of cavity BPM pick-up were designed and fabricated to test the RF characteristics. Also, the beam test of a cavity BPM pick-up was done in the Injector Test Facility (ITF). In the beam test, the raw signal properties of the cavity BPM pick-up were measured at a 200 pC bunch charge. According to the RF test and beam test results, the prototype cavity BPM pick-up design was confirmed to meet the requirements of the PAL-XFEL cavity BPM system.

The continued development of the Spallation Neutron Source external antenna H- ion sourcea)

NASA Astrophysics Data System (ADS)

Welton, R. F.; Carmichael, J.; Desai, N. J.; Fuga, R.; Goulding, R. H.; Han, B.; Kang, Y.; Lee, S. W.; Murray, S. N.; Pennisi, T.; Potter, K. G.; Santana, M.; Stockli, M. P.

2010-02-01

The U.S. Spallation Neutron Source (SNS) is an accelerator-based, pulsed neutron-scattering facility, currently in the process of ramping up neutron production. In order to ensure that the SNS will meet its operational commitments as well as provide for future facility upgrades with high reliability, we are developing a rf-driven, H- ion source based on a water-cooled, ceramic aluminum nitride (AlN) plasma chamber. To date, early versions of this source have delivered up to 42 mA to the SNS front end and unanalyzed beam currents up to ˜100 mA (60 Hz, 1 ms) to the ion source test stand. This source was operated on the SNS accelerator from February to April 2009 and produced ˜35 mA (beam current required by the ramp up plan) with availability of ˜97%. During this run several ion source failures identified reliability issues, which must be addressed before the source re-enters production: plasma ignition, antenna lifetime, magnet cooling, and cooling jacket integrity. This report discusses these issues, details proposed engineering solutions, and notes progress to date.

Upgrades to the NSTX HHFW antenna

NASA Astrophysics Data System (ADS)

Ellis, R.; Brunkhorst, C.; Hosea, J.

2014-02-01

The High Harmonic Fast Wave (HHFW) antenna for the National Spherical Torus Experiment (NSTX) at PPPL will be upgraded as part of the NSTX upgrade project. Higher magnetic fields and plasma current result in disruption forces on the current straps that can be up to four times the original design values. The current straps on the HHFW antenna are presently fed by coaxial feedthroughs with rigid center conductors. The additional forces on the current straps require a compliant section in the center conductor in order to minimize the forces on the feedthrough. The design of this compliant section has been an integrated effort involving electrostatic calculations in parallel with mechanical and thermal analyses, in order to arrive at a design that is optimized for mechanical, thermal and electrical considerations. The voltage standoff obtained from this design will be verified when a prototype antenna is evaluated on our RF test stand. This paper describes the design of the compliant section of the center conductor, mechanical, thermal and electrostatic calculations, and plans for full implementation of the upgrade on NSTX.

10. "TEST STAND 15, AIR FORCE FLIGHT TEST CENTER." ca. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

10. "TEST STAND 1-5, AIR FORCE FLIGHT TEST CENTER." ca. 1958. Test Area 1-115. Original is a color print, showing Test Stand 1-5 from below, also showing the superstructure of TS1-4 at left. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Leuhman Ridge near Highways 58 & 395, Boron, Kern County, CA

Stennis Space Center Conducts Water Flow Test On The B-2 Test Stand

NASA Image and Video Library

2018-05-04

Stennis Space Center completed a water flow test of the refurbished B-2 Test Stand on May 4, 2018. This included both the deflector and the aspirator, individually and together. This test stand is being prepared for the testing of the Space Launch System's booster core, which will utilize four RS-25 rocket engines.

SSC Test Operations Contract Overview

NASA Technical Reports Server (NTRS)

Kleim, Kerry D.

2010-01-01

This slide presentation reviews the Test Operations Contract at the Stennis Space Center (SSC). There are views of the test stands layouts, and closer views of the test stands. There are descriptions of the test stand capabilities, some of the other test complexes, the Cryogenic propellant storage facility, the High Pressure Industrial Water (HPIW) facility, and Fluid Component Processing Facility (FCPF).

A-3 Test Stand work

NASA Image and Video Library

2011-07-29

Rocket engine propellant tanks and cell dome top the A-3 Test Stand under construction at Stennis Space Center. The stand will test next-generation rocket engines that could carry humans beyond low-Earth orbit into deep space once more.

40 CFR 63.9285 - Am I subject to this subpart?

Code of Federal Regulations, 2010 CFR

2010-07-01

...) National Emission Standards for Hazardous Air Pollutants for Engine Test Cells/Stands What This Subpart... engine test cell/stand that is located at a major source of HAP emissions. (a) An engine test cell/stand...

40 CFR 63.9285 - Am I subject to this subpart?

Code of Federal Regulations, 2014 CFR

2014-07-01

...) National Emission Standards for Hazardous Air Pollutants for Engine Test Cells/Stands What This Subpart... engine test cell/stand that is located at a major source of HAP emissions. (a) An engine test cell/stand...

40 CFR 63.9285 - Am I subject to this subpart?

Code of Federal Regulations, 2013 CFR

2013-07-01

...) National Emission Standards for Hazardous Air Pollutants for Engine Test Cells/Stands What This Subpart... engine test cell/stand that is located at a major source of HAP emissions. (a) An engine test cell/stand...

40 CFR 63.9285 - Am I subject to this subpart?

Code of Federal Regulations, 2011 CFR

2011-07-01

...) National Emission Standards for Hazardous Air Pollutants for Engine Test Cells/Stands What This Subpart... engine test cell/stand that is located at a major source of HAP emissions. (a) An engine test cell/stand...

40 CFR 63.9285 - Am I subject to this subpart?

Code of Federal Regulations, 2012 CFR

2012-07-01

...) National Emission Standards for Hazardous Air Pollutants for Engine Test Cells/Stands What This Subpart... engine test cell/stand that is located at a major source of HAP emissions. (a) An engine test cell/stand...

Saturn Apollo Program

NASA Image and Video Library

1964-10-01

Test firing of the Saturn I S-I Stage (S-1-10) at the Marshall Space Flight Center. This test stand was originally constructed in 1951 and sometimes called the Redstone or T tower. In l961, the test stand was modified to permit static firing of the S-I/S-IB stages, which produced a total thrust of 1,600,000 pounds. The name of the stand was then changed to the S-IB Static Test Stand.

Use of a unipedal standing test to assess the ambulation reacquisition time during the early postoperative stage after hip fracture in elderly Japanese: prospective study.

PubMed

Murata, Koichi; Sugitani, Shigeki; Yoshioka, Hiroki; Noguchi, Takashi; Aoto, Toshiyuki; Nakamura, Takashi

2010-01-01

The aim of this study was to predict the ambulation reacquisition time after hip fracture in elderly people using the unipedal standing test during the early postoperative stage. Patients with an intertrochanteric fracture treated with internal fixation (n = 35) and patients with a femoral neck fracture treated with hemiarthroplasty (n = 22) were included. A unipedal standing test using the nonoperated leg was performed on days 3 and 7 after the operation. Among the patients with an intertrochanteric fracture, those with a positive result on the unipedal standing test on postoperative day (POD) 3 attained gait with parallel guide bars (BG) and walker-assisted gait (WG) significantly earlier than did patients with a negative result on the unipedal standing test. Patients with a positive result on the unipedal standing test on POD 7 attained BG, WG, and cane-assisted gait (CG) significantly earlier than did patients with a negative test. Among patients with a femoral neck fracture, those with a positive unipedal standing test result on POD 3 attained BG, WG, and CG significantly earlier than did patients with a negative test. Those with a positive test result on POD 7 attained BG, WG, and CG significantly earlier than did patients with a negative test. The unipedal standing test given during the early postoperative stage is a good test for predicting the ambulation reacquisition time. Moreover, it gives information that can help determine the need for subacute rehabilitation and about discharge planning and health service provision.

NASA Johnson Space Center: White Sands Test Facility

NASA Technical Reports Server (NTRS)

Aggarwal, Pravin; Kowalski, Robert R.

2011-01-01

This slide presentation reviews the testing facilities and laboratories available at the White Sands Test Facility (WSTF). The mission of WSTF is to provide the expertise and infrastructure to test and evaluate spacecraft materials, components and propulsion systems that enable the safe exploration and use of space. There are nine rocket test stands in two major test areas, six altitude test stands, three ambient test stands,

17. HISTORIC VIEW OF ROCKET & LAUNCH STAND DESIGNED BY ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

17. HISTORIC VIEW OF ROCKET & LAUNCH STAND DESIGNED BY HERMANN OBERTH AND RUDOLF NEBEL FOR THE MOVIE DIE FRAU IM MOND (THE WOMAN ON THE MOON). THE LAUNCH STAND WAS MODIFIED BY THE VFR FOR THE FIRST TEST STAND AT RAKETENFLUGPLATZ NEAR BERLIN. - Marshall Space Flight Center, Redstone Rocket (Missile) Test Stand, Dodd Road, Huntsville, Madison County, AL

1. ROCKET ENGINE TEST STAND, LOCATED IN THE NORTHEAST ¼ ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. ROCKET ENGINE TEST STAND, LOCATED IN THE NORTHEAST ¼ OF THE X-15 ENGINE TEST COMPLEX. Looking northeast. - Edwards Air Force Base, X-15 Engine Test Complex, Rocket Engine & Complete X-15 Vehicle Test Stands, Rogers Dry Lake, east of runway between North Base & South Base, Boron, Kern County, CA

3. COMPLETE X15 VEHICLE TEST STAND, LOCATED IN SOUTHEAST ¼ ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

3. COMPLETE X-15 VEHICLE TEST STAND, LOCATED IN SOUTHEAST ¼ OF X-15 ENGINE TEST COMPLEX. Looking northeast. - Edwards Air Force Base, X-15 Engine Test Complex, Rocket Engine & Complete X-15 Vehicle Test Stands, Rogers Dry Lake, east of runway between North Base & South Base, Boron, Kern County, CA

CSG delivery and installation

NASA Image and Video Library

2010-10-27

The first of nine chemical steam generator (CSG) units that will be used on the A-3 Test Stand is hoisted into place at the E-2 Test Stand at John C. Stennis Space Center on Oct. 24, 2010. The unit was installed at the E-2 stand for verification and validation testing before it is moved to the A-3 stand. Steam generated by the nine CSG units that will be installed on the A-3 stand will create a vacuum that allows Stennis operators to test next-generation rocket engines at simulated altitudes up to 100,000 feet.

3. BUILDING 8767, NORTH REAR AND WEST SIDE, TEST STAND ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

3. BUILDING 8767, NORTH REAR AND WEST SIDE, TEST STAND 1-A AT FAR RIGHT. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Observation Bunkers for Test Stand 1-A, Test Area 1-120, north end of Jupiter Boulevard, Boron, Kern County, CA

5. FLAME DEFLECTOR, COMPLETE X15 VEHICLE TEST STAND. Looking east. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

5. FLAME DEFLECTOR, COMPLETE X-15 VEHICLE TEST STAND. Looking east. - Edwards Air Force Base, X-15 Engine Test Complex, Rocket Engine & Complete X-15 Vehicle Test Stands, Rogers Dry Lake, east of runway between North Base & South Base, Boron, Kern County, CA

MR-compatibility assessment of MADPET4: a study of interferences between an SiPM-based PET insert and a 7 T MRI system

NASA Astrophysics Data System (ADS)

Omidvari, Negar; Topping, Geoffrey; Cabello, Jorge; Paul, Stephan; Schwaiger, Markus; Ziegler, Sibylle I.

2018-05-01

Compromises in the design of a positron emission tomography (PET) insert for a magnetic resonance imaging (MRI) system should minimize the deterioration of image quality in both modalities, particularly when simultaneous demanding acquisitions are performed. In this work, the advantages of using individually read-out crystals with high-gain silicon photomultipliers (SiPMs) were studied with a small animal PET insert for a 7 T MRI system, in which the SiPM charge was transferred to outside the MRI scanner using coaxial cables. The interferences between the two systems were studied with three radio-frequency (RF) coil configurations. The effects of PET on the static magnetic field, flip angle distribution, RF noise, and image quality of various MRI sequences (gradient echo, spin echo, and echo planar imaging (EPI) at 1H frequency, and chemical shift imaging at 13C frequency) were investigated. The effects of fast-switching gradient fields and RF pulses on PET count rate were studied, while the PET insert and the readout electronics were not shielded. Operating the insert inside a 1H volume coil, used for RF transmission and reception, limited the MRI to T1-weighted imaging, due to coil detuning and RF attenuation, and resulted in significant PET count loss. Using a surface receive coil allowed all tested MR sequences to be used with the insert, with 45–59% signal-to-noise ratio (SNR) degradation, compared to without PET. With a 1H/13C volume coil inside the insert and shielded by a copper tube, the SNR degradation was limited to 23–30% with all tested sequences. The insert did not introduce any discernible distortions into images of two tested EPI sequences. Use of truncated sinc shaped RF excitation pulses and gradient field switching had negligible effects on PET count rate. However, PET count rate was substantially affected by high-power RF block pulses and temperature variations due to high gradient duty cycles.

Multipole and field uniformity tailoring of a 750 MHz rf dipole

DOE Office of Scientific and Technical Information (OSTI.GOV)

Delayen, Jean R.; Castillo, Alejandro

2014-12-01

In recent years great interest has been shown in developing rf structures for beam separation, correction of geometrical degradation on luminosity, and diagnostic applications in both lepton and hadron machines. The rf dipole being a very promising one among all of them. The rf dipole has been tested and proven to have attractive properties that include high shunt impedance, low and balance surface fields, absence of lower order modes and far-spaced higher order modes that simplify their damping scheme. As well as to be a compact and versatile design in a considerable range of frequencies, its fairly simple geometry dependencymore » is suitable both for fabrication and surface treatment. The rf dipole geometry can also be optimized for lowering multipacting risk and multipole tailoring to meet machine specific field uniformity tolerances. In the present work a survey of field uniformities, and multipole contents for a set of 750 MHz rf dipole designs is presented as both a qualitative and quantitative analysis of the inherent flexibility of the structure and its limitations.« less

DC currents collected by a RF biased electrode quasi-parallel to the magnetic field

NASA Astrophysics Data System (ADS)

Faudot, E.; Devaux, S.; Moritz, J.; Bobkov, V.; Heuraux, S.

2017-10-01

Local plasma biasings due to RF sheaths close to ICRF antennas result mainly in a negative DC current collection on the antenna structure. In some specific cases, we may observe positive currents when the ion mobility (seen from the collecting surface) overcomes the electron one or/and when the collecting surface on the antenna side becomes larger than the other end of the flux tube connected to the wall. The typical configuration is when the antenna surface is almost parallel to the magnetic field lines and the other side perpendicular. To test the optimal case where the magnetic field is quasi-parallel to the electrode surface, one needs a linear magnetic configuration as our magnetized RF discharge experiment called Aline. The magnetic field angle is in our case lower than 1 relative to the RF biased surface. The DC current flowing through the discharge has been measured as a function of the magnetic field strength, neutral gas (He) pressure and RF power. The main result is the reversal of the DC current depending on the magnetic field, collision frequency and RF power level.

Optimization of a RF-generated CF4/O2 gas plasma sterilization process.

PubMed

Lassen, Klaus S; Nordby, Bolette; Grün, Reinar

2003-05-15

A sterilization process with the use of RF-generated (13.56 MHz) CF(4)/O(2) gas plasma was optimized in regards to power, flow rate, exposure time, and RF-system type. The dependency of the sporicidal effect on the spore inoculum positioning in the chamber of the RF systems was also investigated. Dried Bacillus stearothermophilus ATCC 7953 endospores were used as test organisms. The treatments were evaluated on the basis of survival curves and corresponding D values. The only parameter found to affect the sterilization process was the power of the RF system. Higher power resulted in higher kill. Finally, when the samples were placed more than 3-8 cm away from a centrally placed electrode in System 2, the sporicidal effect was reduced. The results are discussed and compared to results from the present literature. The RF excitation source is evaluated to be more appropriate for sterilization processes than the MW source. Copyright 2003 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 65B: 239-244, 2003

Low power radiofrequency electromagnetic radiation for the treatment of pain due to osteoarthritis of the knee.

PubMed

Alcidi, L; Beneforti, E; Maresca, M; Santosuosso, U; Zoppi, M

2007-01-01

To investigate the analgesic effect of low power radiofrequency electromagnetic radiation (RF) in osteoarthritis (OA) of the knee. In a randomized study on 40 patients the analgesic effect of RF was compared with the effect of transcutaneous electrical nerve stimulation (TENS). RF and TENS applications were repeated every day for a period of 5 days. The therapeutic effect was evaluated by a visual analogue scale (VAS) and by Lequesne's index: tests were performed before, immediately after and 30 days after therapy. RF therapy induced a statistically significant and long lasting decrease of VAS and of Lequesne's index; TENS induced a decrease of VAS and of Lequesne's index which was not statistically significant. A therapeutic effect of RF was therefore demonstrated on pain and disability due to knee OA. This effect was better than the effect of TENS, which is a largely used analgesic technique. Such a difference of the therapeutic effect may be due to the fact that TENS acts only on superficial tissues and nerve terminals, while RF acts increasing superficial and deep tissue temperature.

On-command drug release from nanochains inhibits growth of breast tumors

PubMed Central

Peiris, Pubudu M.; Tam, Morgan; Vicente, Peter; Abramowski, Aaron; Toy, Randall; Bauer, Lisa; Mayer, Aaron; Pansky, Jenna; Doolittle, Elizabeth; Tucci, Samantha; Schmidt, Erik; Shoup, Christopher; Rao, Swetha; Murray, Kaitlyn; Gopalakrishnan, Ramamurthy; Keri, Ruth A.; Basilion, James P.; Griswold, Mark A.; Karathanasis, Efstathios

2013-01-01

Purpose To evaluate the ability of radiofrequency (RF)-triggered drug release from a multicomponent chain-shaped nanoparticle to inhibit the growth of an aggressive breast tumor. Methods A two-step solid phase chemistry was employed to synthesize doxorubicin-loaded nanochains, which were composed of three iron oxide nanospheres and one doxorubicin-loaded liposome assembled in a 100-nm-long linear nanochain. The nanochains were tested in the Luc-GFP-4T1 orthotopic mouse model, which is a highly aggressive breast cancer model. The Luc-GFP-4T1 cell line stably expresses firefly luciferase, which allowed the non-invasive in vivo imaging of tumor response to the treatment using bioluminescence imaging (BLI). Results Longitudinal BLI imaging showed that a single nanochain treatment followed by application of RF resulted in an at least 100-fold lower BLI signal compared to the groups treated with nanochains (without RF) or free doxorubicin followed by RF. A statistically significant increase in survival time of the nanochain-treated animals followed by RF (64.3 days) was observed when compared to the nanochain-treated group without RF (35.7 days), free doxorubicin-treated group followed by RF (38.5 days), and the untreated group (30.5 days; n=5 animals per group). Conclusions These studies showed that the combination of RF and nanochains has the potential to effectively treat highly aggressive cancers and prolong survival. PMID:23934254

On-command drug release from nanochains inhibits growth of breast tumors.

PubMed

Peiris, Pubudu M; Tam, Morgan; Vicente, Peter; Abramowski, Aaron; Toy, Randall; Bauer, Lisa; Mayer, Aaron; Pansky, Jenna; Doolittle, Elizabeth; Tucci, Samantha; Schmidt, Erik; Shoup, Christopher; Rao, Swetha; Murray, Kaitlyn; Gopalakrishnan, Ramamurthy; Keri, Ruth A; Basilion, James P; Griswold, Mark A; Karathanasis, Efstathios

2014-06-01

To evaluate the ability of radiofrequency (RF)-triggered drug release from a multicomponent chain-shaped nanoparticle to inhibit the growth of an aggressive breast tumor. A two-step solid phase chemistry was employed to synthesize doxorubicin-loaded nanochains, which were composed of three iron oxide nanospheres and one doxorubicin-loaded liposome assembled in a 100-nm-long linear nanochain. The nanochains were tested in the 4T1-LUC-GFP orthotopic mouse model, which is a highly aggressive breast cancer model. The 4T1-LUC-GFP cell line stably expresses firefly luciferase, which allowed the non-invasive in vivo imaging of tumor response to the treatment using bioluminescence imaging (BLI). Longitudinal BLI imaging showed that a single nanochain treatment followed by application of RF resulted in an at least 100-fold lower BLI signal compared to the groups treated with nanochains (without RF) or free doxorubicin followed by RF. A statistically significant increase in survival time of the nanochain-treated animals followed by RF (64.3 days) was observed when compared to the nanochain-treated group without RF (35.7 days), free doxorubicin-treated group followed by RF (38.5 days), and the untreated group (30.5 days; n=5 animals per group). These studies showed that the combination of RF and nanochains has the potential to effectively treat highly aggressive cancers and prolong survival.

The association of immunoglobulin A, immunoglobulin G and anti-cyclic citrullinated peptide antibodies with disease activity in seronegative rheumatoid arthritis patients.

PubMed

Karimifar, Mansoor; Moussavi, Hamidreza; Babaei, Mehran; Akbari, Mojtaba

2014-09-01

Rheumatoid arthritis (RA) is a common autoimmune disease that is associated with progressive disability, systemic complications, and early death. The present study was aimed to investigate the level of immunoglobulin G (IgG) and IgA isotypes and anti-cyclic citrullinated peptide (CCP) antibody and to assess their association with disease severity based on disease activity score (DAS-28) in patients with IgM rheumatoid factor (IgM-RF) negative RA. In this cross-sectional study, 62 RA patients with IgM-RF negative were assessed. Radiographs were obtained for all RA patients. The RF (IgG, and IgA) and anti-CCP were measured by using the enzyme-linked immunosorbent assay. Values of cut-off points over 15 UI/mL for IgA IgA-RF, 20 UI/mL for IgG-RF and over 20 units for anti-CCP were considered positive. DAS-28 score was compared in regard to the IgA-RF and IgG-RF and anti-CCP positivity using Mann-Whitney test. DAS-28 score in IgA-RF positive was significantly higher than IgA-RF negative (mean score, 6.03 ± 0.33 vs. 5.44 ± 0.76 respectively, P = 0.035). In IgG-RF positive patients, DAS-28 score was similar to patients with IgG-RF negative (5.64 ± 0.59 vs. 5.46 ± 0.78 respectively, P = 0.396). Furthermore, in patients with anti-CCP positive DAS-28 score was significantly higher than patients with anti-CCP negative (5.72 ± 0.61 vs. 5.38 ± 0.79 respectively, P = 0.049). Findings indicated that there was a significant association between the amounts of IgA and anti-CCP with severity of disease in RF negative RA patients while there was no significant association between the amounts of IgG and severity of RA disease.

Credit WCT. Photographic copy of photograph, view looking south down ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Credit WCT. Photographic copy of photograph, view looking south down easternmost tunnel axis during second phase of JPL tunnel construction in 1959. Reinforced concrete formwork for Test Stand "D" foundation appears in left foreground. Formwork for Building 4222/E-23 (Test Stand "D" Workshop) is in place in right foreground with disturbed earth for western leg of tunnel system evident in background. Test Stand "C" is in center background, where first phase of tunnel construction ended. Test Stand "A" appears as tower in right background. (JPL negative no. 384-1838-C, 9 March 1959) - Jet Propulsion Laboratory Edwards Facility, Test Stand D, Edwards Air Force Base, Boron, Kern County, CA

High power millimeter wave experiment of ITER relevant electron cyclotron heating and current drive system.

PubMed

Takahashi, K; Kajiwara, K; Oda, Y; Kasugai, A; Kobayashi, N; Sakamoto, K; Doane, J; Olstad, R; Henderson, M

2011-06-01

High power, long pulse millimeter (mm) wave experiments of the RF test stand (RFTS) of Japan Atomic Energy Agency (JAEA) were performed. The system consists of a 1 MW/170 GHz gyrotron, a long and short distance transmission line (TL), and an equatorial launcher (EL) mock-up. The RFTS has an ITER-relevant configuration, i.e., consisted by a 1 MW-170 GHz gyrotron, a mm wave TL, and an EL mock-up. The TL is composed of a matching optics unit, evacuated circular corrugated waveguides, 6-miter bends, an in-line waveguide switch, and an isolation valve. The EL-mock-up is fabricated according to the current design of the ITER launcher. The Gaussian-like beam radiation with the steering capability of 20°-40° from the EL mock-up was also successfully proved. The high power, long pulse power transmission test was conducted with the metallic load replaced by the EL mock-up, and the transmission of 1 MW/800 s and 0.5 MW/1000 s was successfully demonstrated with no arcing and no damages. The transmission efficiency of the TL was 96%. The results prove the feasibility of the ITER electron cyclotron heating and current drive system. © 2011 American Institute of Physics

10. OBSERVATION POST NO. 3, WEST OF TEST STAND 1A. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

10. OBSERVATION POST NO. 3, WEST OF TEST STAND 1-A. SOUTH SIDE AND EAST FRONT. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Observation Bunkers for Test Stand 1-A, Test Area 1-120, north end of Jupiter Boulevard, Boron, Kern County, CA

Detail of north side of Test Stand 'A' base, showing ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Detail of north side of Test Stand 'A' base, showing tanks for distilled water (left), fuel (center), and gaseous nitrogen (right). Other tanks present for tests were removed before this image was taken. - Jet Propulsion Laboratory Edwards Facility, Test Stand A, Edwards Air Force Base, Boron, Kern County, CA

6. CABLE RACK, MEZZANINE LEVEL, INTERIOR OF TEST STAND 1A. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

6. CABLE RACK, MEZZANINE LEVEL, INTERIOR OF TEST STAND 1A. Looking south from north wall of terminal room. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-A Terminal Room, Test Area 1-120, north end of Jupiter Boulevard, Boron, Kern County, CA

7. ROCKET SLED ON DECK OF TEST STAND 15. Photo ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

7. ROCKET SLED ON DECK OF TEST STAND 1-5. Photo no. "6085, G-EAFB-16 SEP 52." Looking south to machine shop. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-5, Test Area 1-115, northwest end of Saturn Boulevard, Boron, Kern County, CA

KEITH HIGGINBOTHAM AT TEST STAND 4699

NASA Image and Video Library

2016-10-17

KEITH HIGGINBOTHAM, STRUCTURAL TEST LEAD FOR THE SLS SPACECRAFT PAYLOAD INTEGRATION AND EVOLUTION OFFICE, IS SHOWN BESIDE TEST STAND 4699 AT THE MARSHALL SPACE FLIGHT CENTER’S WEST TEST AREA. HIGGINBOTHAM WILL BE LEADING STRUCTURAL LOADS TESTING AT TEST STAND 4699 FOR THE CORE STAGE SIMULATER AND THE LAUNCH VEHICLE STAGE ADAPTER. THE TEST SERIES WILL ENSURE EACH STRUCTURE CAN WITHSTAND THE INCREDIBLE STRESSES OF LAUNCH.

High gradient tests of metallic mm-wave accelerating structures

DOE PAGES

Dal Forno, Massimo; Dolgashev, Valery; Bowden, Gordon; ...

2017-05-10

This study explores the physics of vacuum rf breakdowns in high gradient mm-wave accelerating structures. We performed a series of experiments with 100 GHz and 200 GHz metallic accelerating structures, at the Facility for Advanced Accelerator Experimental Tests (FACET) at the SLAC National Accelerator Laboratory. This paper presents the experimental results of rf tests of 100 GHz travelling-wave accelerating structures, made of hard copper-silver alloy. The results are compared with pure hard copper structures. The rf fields were excited by the FACET ultra-relativistic electron beam. The accelerating structures have open geometries, 10 cm long, composed of two halves separated bymore » a variable gap. The rf frequency of the fundamental accelerating mode depends on the gap size and can be changed from 90 GHz to 140 GHz. The measured frequency and pulse length are consistent with our simulations. When the beam travels off-axis, a deflecting field is induced in addition to the decelerating longitudinal field. We measured the deflecting forces by observing the displacement of the electron bunch and used this measurement to verify the expected accelerating gradient. We present the first quantitative measurement of rf breakdown rates in 100 GHz copper-silver accelerating structure, which was 10 –3 per pulse, with peak electric field of 0.42 GV/m, an accelerating gradient of 127 MV/m, at a pulse length of 2.3 ns. The goal of our studies is to understand the physics of gradient limitations in order to increase the energy reach of future accelerators.« less

High gradient tests of metallic mm-wave accelerating structures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dal Forno, Massimo; Dolgashev, Valery; Bowden, Gordon

This study explores the physics of vacuum rf breakdowns in high gradient mm-wave accelerating structures. We performed a series of experiments with 100 GHz and 200 GHz metallic accelerating structures, at the Facility for Advanced Accelerator Experimental Tests (FACET) at the SLAC National Accelerator Laboratory. This paper presents the experimental results of rf tests of 100 GHz travelling-wave accelerating structures, made of hard copper-silver alloy. The results are compared with pure hard copper structures. The rf fields were excited by the FACET ultra-relativistic electron beam. The accelerating structures have open geometries, 10 cm long, composed of two halves separated bymore » a variable gap. The rf frequency of the fundamental accelerating mode depends on the gap size and can be changed from 90 GHz to 140 GHz. The measured frequency and pulse length are consistent with our simulations. When the beam travels off-axis, a deflecting field is induced in addition to the decelerating longitudinal field. We measured the deflecting forces by observing the displacement of the electron bunch and used this measurement to verify the expected accelerating gradient. We present the first quantitative measurement of rf breakdown rates in 100 GHz copper-silver accelerating structure, which was 10 –3 per pulse, with peak electric field of 0.42 GV/m, an accelerating gradient of 127 MV/m, at a pulse length of 2.3 ns. The goal of our studies is to understand the physics of gradient limitations in order to increase the energy reach of future accelerators.« less

EVALUATION OF PERFORMANCE AND COMPOSITION SHIFT OF ZEOTROPIC MIXTURES IN A LORENZ-MEUTZNER REFRIGERATOR/FREEZER

EPA Science Inventory

Results from previous testing of this refrigerator/freezer (R/F) using a 750 Btu/hr compressor and several zeotrophic mixtures revealed a performance enhancement up to 16 percent above that of HFC-134a. In the study presented in this paper, the Lorenz-Meutzner (LM) R/F equipped ...

Suppression of multipacting in high power RF couplers operating with superconducting cavities

NASA Astrophysics Data System (ADS)

Ostroumov, P. N.; Kazakov, S.; Morris, D.; Larter, T.; Plastun, A. S.; Popielarski, J.; Wei, J.; Xu, T.

2017-06-01

Capacitive input couplers based on a 50 Ω coaxial transmission line are frequently used to transmit RF power to superconducting (SC) resonators operating in CW mode. It is well known that coaxial transmission lines are prone to multipacting phenomenon in a wide range of RF power level and operating frequency. The Facility for Rare Isotope Beams (FRIB) being constructed at Michigan State University includes two types of quarter wave SC resonators (QWR) operating at 80.5 MHz and two types of half wave SC resonators (HWR) operating at 322 MHz. As was reported in ref. [1] a capacitive input coupler used with HWRs was experiencing strong multipacting that resulted in a long conditioning time prior the cavity testing at design levels of accelerating fields. We have developed an insert into 50 Ω coaxial transmission line that provides opportunity to bias the RF coupler antenna and protect the amplifier from the bias potential in the case of breakdown in DC isolation. Two of such devices have been built and are currently used for the off-line testing of 8 HWRs installed in the cryomodule.

LOX tank installation

NASA Image and Video Library

2011-06-08

Construction of the A-3 Test Stand at Stennis Space Center continued June 8 with installation of a 35,000-gallon liquid oxygen tank atop the steel structure. The stand is being built to test next-generation rocket engines that will carry humans into deep space once more. The LOX tank and a liquid hydrogen tank to be installed atop the stand later will provide propellants for testing the engines. The A-3 Test Stand is scheduled for completion and activation in 2013.

RF Modal Quantity Gaging

NASA Technical Reports Server (NTRS)

Vanleuven, K.

1989-01-01

The primary objective is to provide a concept of a radio frequency (RF) modal resonance technique which is being investigated as a method for gaging the quantities of subcritical cryogenic propellants in metallic tanks. Of special interest are the potential applications of the technique to microgravity propellant gaging situations. The results of concept testing using cryogenic oxygen, hydrogen, and nitrogen, as well as paraffin simulations of microgravity fluid orientations, are reported. These test results were positive and showed that the gaging concept was viable.

Preparing to Test

NASA Image and Video Library

2015-03-26

Stennis Space Center employees install a 96-inch valve during a recent upgrade of the high-pressure industrial water system that serves the site’s large rocket engine test stands. The upgraded system has a capacity to flow 335,000 gallons of water a minute, which is a critical element for testing. At Stennis, engines are anchored in place on large test stands and fired just as they are during an actual space flight. The fire and exhaust from the test is redirected out of the stand by a large flame trench. A water deluge system directs thousands of gallons of water needed to cool the exhaust. Water also must be available for fire suppression in the event of a mishap. The new system supports RS-25 engine testing on the A-1 Test Stand, as well as testing of the core stage of NASA’s new Space Launch System on the B-2 Test Stand at Stennis.

[Research and workshop on alternative fuels for aviation. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1999-09-01

The Renewable Aviation Fuels Development Center (RAFDC) at Baylor University was granted U. S. Department of Energy (US DOE) and Federal Aviation Administration (FAA) funds for research and development to improve the efficiency in ethanol powered aircraft, measure performance and compare emissions of ethanol, Ethyl Tertiary Butyl Ether (ETBE) and 100 LL aviation gasoline. The premise of the initial proposal was to use a test stand owned by Engine Components Inc. (ECI) based in San Antonio, Texas. After the grant was awarded, ECI decided to close down its test stand facility. Since there were no other test stands available atmore » that time, RAFDC was forced to find additional support to build its own test stand. Baylor University provided initial funds for the test stand building. Other obstacles had to be overcome in order to initiate the program. The price of the emission testing equipment had increased substantially beyond the initial quote. Rosemount Analytical Inc. gave RAFDC an estimate of $120,000.00 for a basic emission testing package. RAFDC had to find additional funding to purchase this equipment. The electronic ignition unit also presented a series of time consuming problems. Since at that time there were no off-the-shelf units of this type available, one had to be specially ordered and developed. FAA funds were used to purchase a Super Flow dynamometer. Due to the many unforeseen obstacles, much more time and effort than originally anticipated had to be dedicated to the project, with much of the work done on a volunteer basis. Many people contributed their time to the program. One person, mainly responsible for the initial design of the test stand, was a retired engineer from Allison with extensive aircraft engine test stand experience. Also, many Baylor students volunteered to assemble the. test stand and continue to be involved in the current test program. Although the program presented many challenges, which resulted in delays, the RAFDC's test stand is an asset which provides an ongoing research capability dedicated to the testing of alternative fuels for aircraft engines. The test stand is now entirely functional with the exception of the electronic ignition unit which still needs adjustments.« less

Phosphorylation and gene expression of p53 are not affected in human cells exposed to 2.1425 GHz band CW or W-CDMA modulated radiation allocated to mobile radio base stations.

PubMed

Hirose, H; Sakuma, N; Kaji, N; Suhara, T; Sekijima, M; Nojima, T; Miyakoshi, J

2006-09-01

A large-scale in vitro study focusing on low-level radiofrequency (RF) fields from mobile radio base stations employing the International Mobile Telecommunication 2000 (IMT-2000) cellular system was conducted to test the hypothesis that modulated RF fields induce apoptosis or other cellular stress response that activate p53 or the p53-signaling pathway. First, we evaluated the response of human cells to microwave exposure at a specific absorption rate (SAR) of 80 mW/kg, which corresponds to the limit of the average whole-body SAR for general public exposure defined as a basic restriction by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines. Second, we investigated whether continuous wave (CW) and wideband code division multiple access (W-CDMA) modulated signal RF fields at 2.1425 GHz induced apoptosis or any signs of stress. Human glioblastoma A172 cells were exposed to W-CDMA radiation at SARs of 80, 250, and 800 mW/kg, and CW radiation at 80 mW/kg for 24 or 48 h. Human IMR-90 fibroblasts from fetal lungs were exposed to both W-CDMA and CW radiation at a SAR of 80 mW/kg for 28 h. Under the RF field exposure conditions described above, no significant differences in the percentage of apoptotic cells were observed between the test groups exposed to RF signals and the sham-exposed negative controls, as evaluated by the Annexin V affinity assay. No significant differences in expression levels of phosphorylated p53 at serine 15 or total p53 were observed between the test groups and the negative controls by the bead-based multiplex assay. Moreover, microarray hybridization and real-time RT-PCR analysis showed no noticeable differences in gene expression of the subsequent downstream targets of p53 signaling involved in apoptosis between the test groups and the negative controls. Our results confirm that exposure to low-level RF signals up to 800 mW/kg does not induce p53-dependent apoptosis, DNA damage, or other stress response in human cells.

B-1 and B-3 Test Stands at NASA’s Plum Brook Station

NASA Image and Video Library

1966-09-21

Operation of the High Energy Rocket Engine Research Facility (B-1), left, and Nuclear Rocket Dynamics and Control Facility (B-3) at the National Aeronautics and Space Administration’s (NASA) Plum Brook Station in Sandusky, Ohio. The test stands were constructed in the early 1960s to test full-scale liquid hydrogen fuel systems in simulated altitude conditions. Over the next decade each stand was used for two major series of liquid hydrogen rocket tests: the Nuclear Engine for Rocket Vehicle Application (NERVA) and the Centaur second-stage rocket program. The different components of these rocket engines could be studied under flight conditions and adjusted without having to fire the engine. Once the preliminary studies were complete, the entire engine could be fired in larger facilities. The test stands were vertical towers with cryogenic fuel and steam ejector systems. B-1 was 135 feet tall, and B-3 was 210 feet tall. Each test stand had several levels, a test section, and ground floor shop areas. The test stands relied on an array of support buildings to conduct their tests, including a control building, steam exhaust system, and fuel storage and pumping facilities. A large steam-powered altitude exhaust system reduced the pressure at the exhaust nozzle exit of each test stand. This allowed B-1 and B-3 to test turbopump performance in conditions that matched the altitudes of space.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dal Forno, Massimo; Dolgashev, Valery; Bowden, Gordon

This study explores the physics of vacuum rf breakdowns in subterahertz high-gradient traveling-wave accelerating structures. We present the experimental results of rf tests of 200 GHz metallic accelerating structures, made of copper and copper-silver. These experiments were carried out at the Facility for Advanced Accelerator Experimental Tests (FACET) at the SLAC National Accelerator Laboratory. The rf fields were excited by the FACET ultrarelativistic electron beam. The traveling-wave structure is an open geometry, 10 cm long, composed of two halves separated by a gap. The rf frequency of the fundamental accelerating mode depends on the gap size and can be changedmore » from 160 to 235 GHz. When the beam travels off axis, a deflecting field is induced in addition to the longitudinal field. We measure the deflecting forces by observing the displacement of the electron bunch and use this measurement to verify the expected accelerating gradient. Furthermore, we present the first quantitative measurement of rf breakdown rates in 200 GHz metallic accelerating structures. The breakdown rate of the copper structure is 10 –2 per pulse, with a peak surface electric field of 500 MV/m and a rf pulse length of 0.3 ns, which at a relatively large gap of 1.5 mm, or one wavelength, corresponds to an accelerating gradient of 56 MV/m. For the same breakdown rate, the copper-silver structure has a peak electric field of 320 MV/m at a pulse length of 0.5 ns. For a gap of 1.1 mm, or 0.74 wavelengths, this corresponds to an accelerating gradient of 50 MV/m.« less

RF Heating of MRI-Assisted Catheter Steering Coils for Interventional MRI.

PubMed

Settecase, Fabio; Hetts, Steven W; Martin, Alastair J; Roberts, Timothy P L; Bernhardt, Anthony F; Evans, Lee; Malba, Vincent; Saeed, Maythem; Arenson, Ronald L; Kucharzyk, Walter; Wilson, Mark W

2011-03-01

The aim of this study was too assess magnetic resonance imaging (MRI) radiofrequency (RF)-related heating of conductive wire coils used in magnetically steerable endovascular catheters. A three-axis microcoil was fabricated onto a 1.8Fr catheter tip. In vitro testing was performed on a 1.5-T MRI system using an agarose gel-filled vessel phantom, a transmit-receive body RF coil, a steady-state free precession pulse sequence, and a fluoroptic thermometry system. Temperature was measured without simulated blood flow at varying distances from the magnet isocenter and at varying flip angles. Additional experiments were performed with laser-lithographed single-axis microcoil-tipped microcatheters in air and in a saline bath with varied grounding of the microcoil wires. Preliminary in vivo evaluation of RF heating was performed in pigs at 1.5 T with coil-tipped catheters in various positions in the common carotid arteries with steady-state free precession pulse sequence on and off and under physiologic-flow and zero-flow conditions. In tissue-mimicking agarose gel, RF heating resulted in a maximal temperature increase of 0.35°C after 15 minutes of imaging, 15 cm from the magnet isocenter. For a single-axis microcoil, maximal temperature increases were 0.73°C to 1.91°C in air and 0.45°C to 0.55°C in saline. In vivo, delayed contrast-enhanced MRI revealed no evidence of vascular injury, and histopathologic sections from the common carotid arteries confirmed the lack of vascular damage. Microcatheter tip microcoils for endovascular catheter steering in MRI experience minimal RF heating under the conditions tested. These data provide the basis for further in vivo testing of this promising technology for endovascular interventional MRI. Copyright © 2011 AUR. Published by Elsevier Inc. All rights reserved.

RADIO FREQUENCY ATTENUATOR

DOEpatents

Giordano, S.

1963-11-12

A high peak power level r-f attenuator that is readily and easily insertable along a coaxial cable having an inner conductor and an outer annular conductor without breaking the ends thereof is presented. Spaced first and second flares in the outer conductor face each other with a slidable cylindrical outer conductor portion therebetween. Dielectric means, such as water, contact the cable between the flares to attenuate the radio-frequency energy received thereby. The cylindrical outer conductor portion is slidable to adjust the voltage standing wave ratio to a low level, and one of the flares is slidable to adjust the attenuation level. An integral dielectric container is also provided. (AFC)

KSC-2009-3788

NASA Image and Video Library

2009-06-18

CAPE CANAVERAL, Fla. – Lightning towers stand like guards around Launch Complex 41 at Cape Canaveral Air Force Station in Florida as the Atlas V/Centaur carrying NASA's Lunar Reconnaissance Orbiter, or LRO, and NASA's Lunar Crater Observation and Sensing Satellite, known as LCROSS, lifts off. LRO and LCROSS are the first missions in NASA's plan to return humans to the moon and begin establishing a lunar outpost by 2020. The LRO also includes seven instruments that will help NASA characterize the moon's surface: DIVINER, LAMP, LEND, LOLA , CRATER, Mini-RF and LROC. Launch was on-time at 5:32 p.m. EDT. Photo credit: NASA/Sandra Joseph, Tony Gray

Verification of radio frequency pasteurization treatment for controlling Aspergillus parasiticus on corn grains.

PubMed

Zheng, Ajuan; Zhang, Lihui; Wang, Shaojin

2017-05-16

Radio frequency (RF) heating has been proposed and tested to achieve a required anti-fungal efficacy on various food samples due to its advantage of deeper penetration depth and better heating uniformity. The purpose of this study was to validate applications of RF treatments for controlling Aspergillus parasiticus in corn while maintaining product quality. A pilot-scale, 27.12MHz, 6kW RF heating system together with hot air heating was used to rapidly pasteurize 3.0kg corn samples. Results showed that the pasteurizing effect of RF heating on Aspergillus parasiticus increased with increasing heating temperature and holding time, and RF heating at 70°C holding in hot air for at least 12min resulted in 5-6 log reduction of Aspergillus parasiticus in corn samples with the moisture content of 15.0% w.b. Furthermore, thermal resistance of Aspergillus parasiticus decreased with increasing moisture content (MC) of corn samples. Quality (MC, water activity - a w , protein, starch, ash, fat, fatty acid, color, electrical conductivity and germination rate) of RF treated corn met the required quality standard used in cereal industry. Therefore, RF treatments can provide an effective and rapid heating method to control Aspergillus parasiticus and maintain acceptable corn quality. Copyright © 2017 Elsevier B.V. All rights reserved.

Vestibular ataxia and its measurement in man

NASA Technical Reports Server (NTRS)

Fregly, A. R.

1974-01-01

Methods involved in and results obtained with a new comprehensive ataxia test battery are described, and definitions of spontaneous and induced vestibular ataxia in man are given in terms of these findings. In addition, the topic of alcohol-induced ataxia in relation to labyrinth function is investigated. Items in the test battery comprise a sharpened Romberg test, in which the subject stands on the floor with eyes closed and arms folded against his chest, feet heel-to-toe, for 60 seconds; an eyes-open walking test; an eyes-open standing test; an eyes-closed standing test; an eyes-closed on-leg standing test; an eyes-closed walk a line test; an eyes-closed heel-to-toe walking test; and supplementary ataxia tests such as the classical Romberg test.

Impact of Fibromyalgia in the Sit-to-Stand-to-Sit Performance Compared With Healthy Controls.

PubMed

Collado-Mateo, Daniel; Adsuar, Jose C; Dominguez-Muñoz, Francisco J; Olivares, Pedro R; Gusi, Narcis

2017-06-01

Fibromyalgia is associated with a reduction in the ability to perform activities of daily living. Sit-to-stand-to-sit performance is one of the most common activities of daily living and often is evaluated by counting the number of repetitions of the 30-second chair-stand test. No study, however, has examined the performance over the 30 seconds of this test of female patients with fibromyalgia on a phase-by-phase basis. To evaluate the impact of fibromyalgia on performance of the 30-second chair-stand test and to analyze how the kinematic performance changed over the 30-second test period. A cross-sectional study. Local association of fibromyalgia. Fifteen females with fibromyalgia and nine healthy female controls. Participants performed the 30-second chair-stand test while wearing a motion capture device. Duration of each sit-to-stand-to-sit phase within the 30-second time limit was compared between groups using repeated measures analysis of variance. The association between duration of phases and scores from the revised version of the Fibromyalgia Impact Questionnaire was tested using bivariate correlations. The duration of impulse and sit-to-stand phases were gradually increased over the 30 seconds of the chair-stand test for women with fibromyalgia compared with healthy controls (P = .04 and P = .02, respectively). The mean duration of these 2 phases was associated with symptom duration and the function domain of the revised version of the Fibromyalgia Impact Questionnaire (P < .05). Also, stiffness was directly associated with the duration of the stand-up phase (P = .04). Kinematic performance during the 30-second chair-stand test differed between women with fibromyalgia and healthy controls. Since sit-to-stand from a chair is a common daily activity, women with fibromyalgia may require specific exercises to improve performance of this task. Not applicable. Copyright © 2017 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

Isopropyl alcohol tank installed at A-3 Test Stand

NASA Technical Reports Server (NTRS)

2009-01-01

An isopropyl alcohol (IPA) tank is lifted into place at the A-3 Test Stand being built at NASA's John C. Stennis Space Center. Fourteen IPA, water and liquid oxygen (LOX) tanks are being installed to support the chemical steam generators to be used on the A-3 Test Stand. The IPA and LOX tanks will provide fuel for the generators. The water will allow the generators to produce steam that will be used to reduce pressure inside the stand's test cell diffuser, enabling operators to simulate altitudes up to 100,000 feet. In that way, operators can perform the tests needed on rocket engines being built to carry humans back to the moon and possibly beyond. The A-3 Test Stand is set for completion and activation in 2011.

Water tank installed at A-3 Test Stand

NASA Technical Reports Server (NTRS)

2009-01-01

A water tank is lifted into place at the A-3 Test Stand being built at NASA's John C. Stennis Space Center. Fourteen water, liquid oxygen (LOX) and isopropyl alcohol (IPA) tanks are being installed to support the chemical steam generators to be used on the A-3 Test Stand. The IPA and LOX tanks will provide fuel for the generators. The water will allow the generators to produce steam that will be used to reduce pressure inside the stand's test cell diffuser, enabling operators to simulate altitudes up to 100,000 feet. In that way, operators can perform the tests needed on rocket engines being built to carry humans back to the moon and possibly beyond. The A-3 Test Stand is set for completion and activation in 2011.

Liquid oxygen tank installed at A-3 Test Stand

NASA Technical Reports Server (NTRS)

2009-01-01

A liquid oxygen (LOX) tank is lifted into place at the A-3 Test Stand being built at NASA's John C. Stennis Space Center. Fourteen LOX, isopropyl alcohol (IPA) and water tanks are being installed to support the chemical steam generators to be used on the A-3 Test Stand. The IPA and LOX tanks will provide fuel for the generators. The water will allow the generators to produce steam that will be used to reduce pressure inside the stand's test cell diffuser, enabling operators to simulate altitudes up to 100,000 feet. In that way, operators can perform the tests needed on rocket engines being built to carry humans back to the moon and possibly beyond. The A-3 Test Stand is set for completion and activation in 2011.

Water tank installed at A-3 Test Stand

NASA Image and Video Library

2009-08-13

A water tank is lifted into place at the A-3 Test Stand being built at NASA's John C. Stennis Space Center. Fourteen water, liquid oxygen (LOX) and isopropyl alcohol (IPA) tanks are being installed to support the chemical steam generators to be used on the A-3 Test Stand. The IPA and LOX tanks will provide fuel for the generators. The water will allow the generators to produce steam that will be used to reduce pressure inside the stand's test cell diffuser, enabling operators to simulate altitudes up to 100,000 feet. In that way, operators can perform the tests needed on rocket engines being built to carry humans back to the moon and possibly beyond. The A-3 Test Stand is set for completion and activation in 2011.

Liquid oxygen tank installed at A-3 Test Stand

NASA Image and Video Library

2009-09-18

A liquid oxygen (LOX) tank is lifted into place at the A-3 Test Stand being built at NASA's John C. Stennis Space Center. Fourteen LOX, isopropyl alcohol (IPA) and water tanks are being installed to support the chemical steam generators to be used on the A-3 Test Stand. The IPA and LOX tanks will provide fuel for the generators. The water will allow the generators to produce steam that will be used to reduce pressure inside the stand's test cell diffuser, enabling operators to simulate altitudes up to 100,000 feet. In that way, operators can perform the tests needed on rocket engines being built to carry humans back to the moon and possibly beyond. The A-3 Test Stand is set for completion and activation in 2011.

Isopropyl alcohol tank installed at A-3 Test Stand

NASA Image and Video Library

2009-09-18

An isopropyl alcohol (IPA) tank is lifted into place at the A-3 Test Stand being built at NASA's John C. Stennis Space Center. Fourteen IPA, water and liquid oxygen (LOX) tanks are being installed to support the chemical steam generators to be used on the A-3 Test Stand. The IPA and LOX tanks will provide fuel for the generators. The water will allow the generators to produce steam that will be used to reduce pressure inside the stand's test cell diffuser, enabling operators to simulate altitudes up to 100,000 feet. In that way, operators can perform the tests needed on rocket engines being built to carry humans back to the moon and possibly beyond. The A-3 Test Stand is set for completion and activation in 2011.

Modal Analysis with the Mobile Modal Testing Unit

NASA Technical Reports Server (NTRS)

Wilder, Andrew J.

2013-01-01

Recently, National Aeronautics and Space Administration's (NASA's) White Sands Test Facility (WSTF) has tested rocket engines with high pulse frequencies. This has resulted in the use of some of WSTF's existing thrust stands, which were designed for static loading, in tests with large dynamic forces. In order to ensure that the thrust stands can withstand the dynamic loading of high pulse frequency engines while still accurately reporting the test data, their vibrational modes must be characterized. If it is found that they have vibrational modes with frequencies near the pulsing frequency of the test, then they must be modified to withstand the dynamic forces from the pulsing rocket engines. To make this determination the Mobile Modal Testing Unit (MMTU), a system capable of determining the resonant frequencies and mode shapes of a structure, was used on the test stands at WSTF. Once the resonant frequency has been determined for a test stand, it can be compared to the pulse frequency of a test engine to determine whether or not that stand can avoid resonance and reliably test that engine. After analysis of test stand 406 at White Sands Test Facility, it was determined that natural frequencies for the structure are located around 75, 125, and 240 Hz, and thus should be avoided during testing.

Robot-operated quality control station based on the UTT method

NASA Astrophysics Data System (ADS)

Burghardt, Andrzej; Kurc, Krzysztof; Szybicki, Dariusz; Muszyńska, Magdalena; Nawrocki, Jacek

2017-03-01

This paper presents a robotic test stand for the ultrasonic transmission tomography (UTT) inspection of stator vane thickness. The article presents the method of the test stand design in Autodesk Robot Structural Analysis Professional 2013 software suite. The performance of the designed test stand solution was simulated in the RobotStudio software suite. The operating principle of the test stand measurement system is presented with a specific focus on the measurement strategy. The results of actual wall thickness measurements performed on stator vanes are presented.

High-voltage terminal test of a test stand for a 1-MV electrostatic accelerator

NASA Astrophysics Data System (ADS)

Park, Sae-Hoon; Kim, Yu-Seok

2015-10-01

The Korea Multipurpose Accelerator Complex has been developing a 300-kV test stand for a 1-MV electrostatic accelerator ion source. The ion source and accelerating tube will be installed in a high-pressure vessel. The ion source in the high-pressure vessel is required to have a high reliability. The test stand has been proposed and developed to confirm the stable operating conditions of the ion source. The ion source will be tested at the test stand to verify the long-time operating conditions. The test stand comprises a 300-kV high-voltage terminal, a battery for the ion-source power, a 60-Hz inverter, 200-MHz radio-frequency power supply, a 5-kV extraction power supply, a 300-kV accelerating tube, and a vacuum system. The results of the 300-kV high-voltage terminal tests are presented in this paper.

RP1 (KEROSENE) STORAGE TANKS ON HILLSIDE EAST OF TEST STAND ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

RP1 (KEROSENE) STORAGE TANKS ON HILLSIDE EAST OF TEST STAND 1-B. THIS TANK FARM SERVES BOTH TEST STANDS 1-A AND 1-B - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Combined Fuel Storage Tank Farm, Test Area 1-120, north end of Jupiter Boulevard, Boron, Kern County, CA

7. CABLE RACK, MEZZANINE LEVEL, INTERIOR OF TEST STAND 1A. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

7. CABLE RACK, MEZZANINE LEVEL, INTERIOR OF TEST STAND 1A. Looking north from north end of the cable tunnel leading toward Control Center. - Edwards Air Force Base, Air Force Rocket Propulsion Laboratory, Test Stand 1-A Terminal Room, Test Area 1-120, north end of Jupiter Boulevard, Boron, Kern County, CA

4. COMPLETE X15 VEHICLE TEST STAND, DETAIL OF THRUST MOUNTING ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

4. COMPLETE X-15 VEHICLE TEST STAND, DETAIL OF THRUST MOUNTING STRUCTURE AT ENGINE END OF PLANE. - Edwards Air Force Base, X-15 Engine Test Complex, Rocket Engine & Complete X-15 Vehicle Test Stands, Rogers Dry Lake, east of runway between North Base & South Base, Boron, Kern County, CA

2. ROCKET ENGINE TEST STAND, SHOWING TANK (BUILDING 1929) AND ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

2. ROCKET ENGINE TEST STAND, SHOWING TANK (BUILDING 1929) AND GARAGE (BUILDING 1930) AT LEFT REAR. Looking to west. - Edwards Air Force Base, X-15 Engine Test Complex, Rocket Engine & Complete X-15 Vehicle Test Stands, Rogers Dry Lake, east of runway between North Base & South Base, Boron, Kern County, CA

Rapid HIV testing experience at Veterans Affairs North Texas Health Care System's Homeless Stand Downs.

PubMed

Hooshyar, Dina; Surís, Alina M; Czarnogorski, Maggie; Lepage, James P; Bedimo, Roger; North, Carol S

2014-01-01

In the USA, 21% of the estimated 1.1 million people living with human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS) are unaware they are HIV-infected. In 2011, Veterans Health Administration (VHA)'s Office of Public Health in conjunction with VHA's Health Care for Homeless Veterans Program funded grants to support rapid HIV testing at homeless outreach events because homeless populations are more likely to obtain emergent rather than preventive care and have a higher HIV seroprevalence as compared to the general population. Because of a Veterans Affairs North Texas Health Care System (VANTHCS)'s laboratory testing requirement, VANTHCS partnered with community agencies to offer rapid HIV testing for the first time at VANTHCS' 2011 Homeless Stand Downs in Dallas, Fort Worth, and Texoma, Texas. Homeless Stand Downs are outreach events that connect Veterans with services. Veterans who declined testing were asked their reasons for declining. Comparisons by Homeless Stand Down site used Pearson χ², substituting Fisher's Exact tests for expected cell sizes <5. Of the 910 Veterans attending the Homeless Stand Downs, 261 Veterans reported reasons for declining HIV testing, and 133 Veterans were tested, where 92% of the tested Veterans obtained their test results at the events - all tested negative. Veterans' reported reasons for declining HIV testing included previous negative result (n=168), no time to test (n=49), no risk factors (n=36), testing is not a priority (n=11), uninterested in knowing serostatus (n=6), and HIV-infected (n=3). Only "no time to test" differed significantly by Homeless Stand Down site. Nonresponse rate was 54%. Offering rapid HIV testing at Homeless Stand Downs is a promising testing venue since 15% of Veterans attending VANTHCS' Homeless Stand Downs were tested for HIV, and majority obtained their HIV test results at point-of-care while further research is needed to determine how to improve these rates.

Characterization of Compounds with Tumor-Cell Proliferation Inhibition Activity from Mushroom (Phellinus baumii) Mycelia Produced by Solid-State Fermentation.

PubMed

Zhang, Henan; Shao, Qian; Wang, Wenhan; Zhang, Jingsong; Zhang, Zhong; Liu, Yanfang; Yang, Yan

2017-04-27

The inhibition of tumor-cell proliferationbyan organicsolvent extract from the solid-state fermentation of Phellinus baumii mycelia inoculated in rice medium was investigated in vitro. The active compounds inhibiting tumor-cell proliferation were characterized. Results revealed that all (petroleum ether, chloroform, ethyl acetate, and butanol) fractions inhibited tumor-cell proliferation in a dose-dependent fashion. The ethyl acetate extract had the highest inhibitory effecton tumor-cell proliferation, and the butanol fraction had the lowest. Six compounds were isolated and purified from the ethyl acetate extract of P. baumii mycelia by the tandem application of silica-gel column chromatography (SGCC), high-speed countercurrent chromatography (HSCCC), and preparative HPLC. These compounds were identified by NMR and electrospray ionization-mass spectrometry (ESI-MS) spectroscopic methods as ergosterol (RF1), ergosta-7,22-dien-3β-yl pentadecanoate (RF3), 3,4-dihydroxy benzaldehyde(RF6), inoscavinA (RF7), baicalein(RF10), and 24-ethylcholesta-5,22-dien-3β-ol (RF13). To further clarify the activity of these compounds, the cell-proliferation-inhibition tests of these compounds on various tumor cells were carried out and evaluatedin vitro. Results suggested that compounds RF6, RF7, and RF10 had potent inhibition effects on the proliferation of a series of tumor cell lines, including K562, L1210, SW620, HepG2, LNCaP, and MCF-7cells. These findings indicated that P. baumii mycelia produced by solid-state fermentation in rice canbe used to obtain active compounds with the ability to inhibittumor-cell proliferation.

7. BUILDING 604F, INTERIOR OF BULL PEN SHOWING TESTING STAND ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

7. BUILDING 604-F, INTERIOR OF BULL PEN SHOWING TESTING STAND AND HEAVY WOOD LINING ON CONCRETE WALLS. STEEL PLATE ABOVE TEST STAND DEFLECTS SHRAPNEL, SCREEN FURTHER HELPS TO CONTAIN PARTICLES. ONLY SMALL EXPLOSIVES WERE TESTED HERE (GRENADES, MINES, BOMB FUZES, ETC.). - Picatinny Arsenal, 600 Area, Test Areas District, State Route 15 near I-80, Dover, Morris County, NJ

Engineers conduct key water test for A-3 stand

NASA Technical Reports Server (NTRS)

2009-01-01

Water cascades from the A-2 Test Stand at Stennis Space Center as engineers challenge the limits of the high-pressure water system as part of the preparation process for the A-3 Test Stand under construction. Jeff Henderson, test director for Stennis' A Complex, led a series of tests Nov. 16-20, flowing water simultaneously on the A-1 and A-2 stands, followed by the A-1 and B-1 stands, to determine if the high-pressure industrial water facility pumps and the existing pipe system can support the needs of the A-3 stand. The stand is being built to test rocket engines that will carry astronauts beyond low-Earth orbit and will need about 300,000 gallons of water per minute when operating, but the Stennis system never had been tested to that level. The recent tests were successful in showing the water facility pumps can operate at that capacity - reaching 318,000 gallons per minute in one instance. However, officials continue to analyze data to determine if the system can provide the necessary pressure at that capacity and if the delivery system piping is adequate. 'We just think if there's a problem, it's better to identify and address it now rather than when A-3 is finished and it has to be dealt with,' Henderson said.

rf streak camera based ultrafast relativistic electron diffraction.

PubMed

Musumeci, P; Moody, J T; Scoby, C M; Gutierrez, M S; Tran, T

2009-01-01

We theoretically and experimentally investigate the possibility of using a rf streak camera to time resolve in a single shot structural changes at the sub-100 fs time scale via relativistic electron diffraction. We experimentally tested this novel concept at the UCLA Pegasus rf photoinjector. Time-resolved diffraction patterns from thin Al foil are recorded. Averaging over 50 shots is required in order to get statistics sufficient to uncover a variation in time of the diffraction patterns. In the absence of an external pump laser, this is explained as due to the energy chirp on the beam out of the electron gun. With further improvements to the electron source, rf streak camera based ultrafast electron diffraction has the potential to yield truly single shot measurements of ultrafast processes.

Ways to improve the efficiency and reliability of radio frequency driven negative ion sources for fusion.

PubMed

Kraus, W; Briefi, S; Fantz, U; Gutmann, P; Doerfler, J

2014-02-01

Large RF driven negative hydrogen ion sources are being developed at IPP Garching for the future neutral beam injection system of ITER. The overall power efficiency of these sources is low, because for the RF power supply self-excited generators are utilized and the plasma is generated in small cylindrical sources ("drivers") and expands into the source main volume. At IPP experiments to reduce the primary power and the RF power required for the plasma production are performed in two ways: The oscillator generator of the prototype source has been replaced by a transistorized RF transmitter and two alternative driver concepts, a spiral coil, in which the field is concentrated by ferrites, which omits the losses by plasma expansion and a helicon source are being tested.

Design and test of a double-nuclear RF coil for 1H MRI and 13C MRSI at 7 T

NASA Astrophysics Data System (ADS)

Rutledge, Omar; Kwak, Tiffany; Cao, Peng; Zhang, Xiaoliang

2016-06-01

RF coil operation at the ultrahigh field of 7 T is fraught with technical challenges that limit the advancement of novel human in vivo applications at 7 T. In this work, a hybrid technique combining a microstrip transmission line and a lumped-element L-C loop coil to form a double-nuclear RF coil for proton magnetic resonance imaging and carbon magnetic resonance spectroscopy at 7 T was proposed and investigated. Network analysis revealed a high Q-factor and excellent decoupling between the coils. Proton images and localized carbon spectra were acquired with high sensitivity. The successful testing of this novel double-nuclear coil demonstrates the feasibility of this hybrid design for double-nuclear MR imaging and spectroscopy studies at the ultrahigh field of 7 T.

NEARING THE END OF CONSTRUCTION ON THE LOX TEST STAND AT MSFC.

NASA Image and Video Library

2015-01-08

AS THE END OF CONSTRUCTION ON TEST STAND 4697, THE LIQUID OXYGEN TANK TEST STAND AT MARSHALL SPACE FLIGHT CENTER, PROJECT ENGINEERS PHIL HENDRIX, FROM MSFC, AND CURTNEY WALTERS FROM THE U.S. CORP OF ENGINEERS, STUDY PLANS AND PROGRESS.

RF Negative Ion Source Development at IPP Garching

NASA Astrophysics Data System (ADS)

Kraus, W.; McNeely, P.; Berger, M.; Christ-Koch, S.; Falter, H. D.; Fantz, U.; Franzen, P.; Fröschle, M.; Heinemann, B.; Leyer, S.; Riedl, R.; Speth, E.; Wünderlich, D.

2007-08-01

IPP Garching is heavily involved in the development of an ion source for Neutral Beam Heating of the ITER Tokamak. RF driven ion sources have been successfully developed and are in operation on the ASDEX-Upgrade Tokamak for positive ion based NBH by the NB Heating group at IPP Garching. Building on this experience a RF driven H- ion source has been under development at IPP Garching as an alternative to the ITER reference design ion source. The number of test beds devoted to source development for ITER has increased from one (BATMAN) by the addition of two test beds (MANITU, RADI). This paper contains descriptions of the three test beds. Results on diagnostic development using laser photodetachment and cavity ringdown spectroscopy are given for BATMAN. The latest results for long pulse development on MANITU are presented including the to date longest pulse (600 s). As well, details of source modifications necessitated for pulses in excess of 100 s are given. The newest test bed RADI is still being commissioned and only technical details of the test bed are included in this paper. The final topic of the paper is an investigation into the effects of biasing the plasma grid.

Susceptibility of the MMPI-2-RF neurological complaints and cognitive complaints scales to over-reporting in simulated head injury.

PubMed

Bolinger, Elizabeth; Reese, Caitlin; Suhr, Julie; Larrabee, Glenn J

2014-02-01

We examined the effect of simulated head injury on scores on the Neurological Complaints (NUC) and Cognitive Complaints (COG) scales of the Minnesota Multiphasic Personality Inventory-2 Restructured Form (MMPI-2-RF). Young adults with a history of mild head injury were randomly assigned to simulate head injury or give their best effort on a battery of neuropsychological tests, including the MMPI-2-RF. Simulators who also showed poor effort on performance validity tests (PVTs) were compared with controls who showed valid performance on PVTs. Results showed that both scales, but especially NUC, are elevated in individuals simulating head injury, with medium to large effect sizes. Although both scales were highly correlated with all MMPI-2-RF over-reporting validity scales, the relationship of Response Bias Scale to both NUC and COG was much stronger in the simulators than controls. Even accounting for over-reporting on the MMPI-2-RF, NUC was related to general somatic complaints regardless of group membership, whereas COG was related to both psychological distress and somatic complaints in the control group only. Neither scale was related to actual neuropsychological performance, regardless of group membership. Overall, results provide further evidence that self-reported cognitive symptoms can be due to many causes, not necessarily cognitive impairment, and can be exaggerated in a non-credible manner.

Microwave, irrigated, pulsed, or conventional radiofrequency energy source: which energy source for which catheter ablation?

PubMed

Erdogan, Ali; Grumbrecht, Stephan; Neumann, Thomas; Neuzner, Joerg; Pitschner, Heinz F

2003-01-01

The aim of the study was to compare the diameter of endomyocardial lesions induced with the delivery of microwave, cooled, or pulsed energy versus conventional RF energy. In vitro tests were performed in fresh endomyocardial preparations of pig hearts in a 10-L bath of NaCl 0.9% solution at 37 degrees C and constant 1.5 L/min flow. Ablation 7 Fr catheters with 4-mm tip electrodes were used, except for the delivery of microwave energy. Energy delivery time was set to 60 s/50 W in all experiments. Cooled energy delivery was performed with a closed irrigation catheter. Pulsed energy delivery was performed using a special controller with a duty-cycle of 5 ms. Microwave energy was delivered with a 2.5-GHz generator and 10-mm antenna. Electrode temperature and impedance were measured simultaneously. After ablation, lesion length, width, and depth were measured with microcalipers, and volume calculated by a formula for ellipsoid bodies. Each energy delivery mode was tested in ten experiments. The deepest lesions were created with cooled energy delivery, and the largest volume by microwave energy delivery. Pulsed RF produced significantly deeper lesions than conventional RF energy delivery. Cooled or pulsed RF energy delivery created deeper transmural lesions than conventional RF. To create linear lesions at anatomically complex sites (isthmus), microwave energy seemed superior by rapidly creating deep and long lesions.

Development for a supercompact X -band pulse compression system and its application at SLAC

DOE PAGES

Wang, Juwen W.; Tantawi, Sami G.; Xu, Chen; ...

2017-11-09

Here, we have successfully designed, fabricated, installed, and tested a super compact X -band SLAC Energy Doubler system at SLAC. It is composed of an elegant 3 dB coupler–mode converter–polarizer coupled to a single spherical energy storage cavity with high Q 0 of 94000 and a diameter less than 12 cm. The available rf peak power of 50 MW can be compressed to a peak average power of more than 200 MW in order to double the kick for the electron bunches in a rf transverse deflector system and greatly improve the measurement resolution of both the electron bunches andmore » the x-ray free-electron laser pulses. The design physics and fabrication as well as the measurement results will be presented in detail. High-power operation has demonstrated the excellent performance of this rf compression system without rf breakdown, sign of pulse heating, and rf radiation.« less

Development for a supercompact X -band pulse compression system and its application at SLAC

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Juwen W.; Tantawi, Sami G.; Xu, Chen

Here, we have successfully designed, fabricated, installed, and tested a super compact X -band SLAC Energy Doubler system at SLAC. It is composed of an elegant 3 dB coupler–mode converter–polarizer coupled to a single spherical energy storage cavity with high Q 0 of 94000 and a diameter less than 12 cm. The available rf peak power of 50 MW can be compressed to a peak average power of more than 200 MW in order to double the kick for the electron bunches in a rf transverse deflector system and greatly improve the measurement resolution of both the electron bunches andmore » the x-ray free-electron laser pulses. The design physics and fabrication as well as the measurement results will be presented in detail. High-power operation has demonstrated the excellent performance of this rf compression system without rf breakdown, sign of pulse heating, and rf radiation.« less

MEASUREMENT OF RF LOSSES DUE TO TRAPPED FLUX IN A LARGE-GRAIN NIOBIUM CAVITY

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gianluigi Ciovati; Alex Gurevich

Trapped magnetic field in superconducting niobium is a well known cause of radio-frequency (RF) residual losses. In this contribution, we present the results of RF tests on a single-cell cavity made of high-purity large grain niobium before and after allowing a fraction of the Earth’s magnetic field to be trapped in the cavity during the cooldown below the critical temperature Tc. This experiment has been done on the cavity before and after a low temperature baking. Temperature mapping allowed us to determine the location of hot-spots with high losses and to measure their field dependence. The results show not onlymore » an increase of the low-field residual resistance, but also a larger increase of the surface resistance for intermediate RF field (higher "medium field Qslope"), which depends on the amount of the trapped flux. These additional field-dependent losses can be described as losses of pinned vortices oscillating under the applied RF magnetic field.« less

Development of a Methodology to Guide the Replacement of Agency Default Uncertainty Factors with Those Based on Data

EPA Science Inventory

The Agency's guidance for the derivation of RfD and RfC values call for the downward adjustment of exposure-response levels observed in animals and/or humans to account for the potentially greater sensitivity of humans as compared to test animals (UFA) and the differential sensit...

Eccentric superconducting RF cavity separator structure

DOEpatents

Aggus, John R.; Giordano, Salvatore T.; Halama, Henry J.

1976-01-01

Accelerator apparatus having an eccentric-shaped, iris-loaded deflecting cavity for an rf separator for a high energy high momentum, charged particle accelerator beam. In one embodiment, the deflector is superconducting, and the apparatus of this invention provides simplified machining and electron beam welding techniques. Model tests have shown that the electrical characteristics provide the desired mode splitting without adverse effects.

Non-Destructive Testing with Atmospheric Pressure Radio-Frequency Plasma

NASA Astrophysics Data System (ADS)

May, A.; Andarawis, E.

2007-03-01

We summarize our recent work using radio-frequency (RF) atmospheric pressure plasma (APP) for non-destructive evaluation (NDE), specifically for: (1) Clearance sensing (0-5mm) on rotating components, and (2) Generation of broadband ultrasound in air at 900kHz. RF-APP showed potential in both of these common NDE requirements, but further work is required to better characterize and optimize the performance of the new techniques. Application of RF-APP to other NDE disciplines, such as plasma spectroscopy and gas flow measurement, is also likely to be advantageous, especially in harsh environments where existing approaches are prohibitively expensive or complex.

CLIC RF High Power Production Testing Program

DOE Office of Scientific and Technical Information (OSTI.GOV)

Syratchev, I.; Riddone, G.; /CERN

The CLIC Power Extraction and Transfer Structure (PETS) is a passive microwave device in which bunches of the drive beam interact with the impedance of the periodically loaded waveguide and generate RF power for the main linac accelerating structure. The demands on the high power production ({approx} 150 MW) and the needs to transport the 100 A drive beam for about 1 km without losses, makes the PETS design rather unique and the operation very challenging. In the coming year, an intense PETS testing program will be implemented. The target is to demonstrate the full performance of the PETS operation.more » The testing program overview and test results available to date are presented.« less

High power microwave components for space communications satellite

NASA Technical Reports Server (NTRS)

Jankowski, H.; Geia, A.

1972-01-01

Analyzed, developed, and tested were high power microwave components for communications satellites systems. Included were waveguide and flange configurations with venting, a harmonic filter, forward and reverse power monitors, electrical fault sensors, and a diplexer for two channel simultaneous transmission. The assembly of 8.36 GHz components was bench tested, and then operated for 60 hours at 3.5 kW CW in a high vacuum. The diplexer was omitted from this test pending a modification of its end irises. An RF leakage test showed only that care is required at flange junctions; all other components were RF tight. Designs were extrapolated for 12 GHz and 2.64 GHz high power satellite systems.

Energy Saving Glass Lamination via Selective Radio Frequency Heating

DOE Office of Scientific and Technical Information (OSTI.GOV)

Allan, Shawn M; Baranova, Inessa; Poley, Joseph

2012-02-27

This project focused on advancing radio-frequency (RF) lamination technology closer to commercial implementation, in order to reduce the energy intensity of glass lamination by up to 90%. Lamination comprises a wide range of products including autoglass, architectural safety and innovative design glass, transparent armor (e.g. bullet proof glass), smart glass, mirrors, and encapsulation of photovoltaics. Lamination is also the fastest growing segment of glass manufacturing, with photovoltaics, architectural needs, and an anticipated transition to laminated side windows in vehicles. The state-of-the-art for glass lamination is to use autoclaves, which apply heat and uniform gas pressure to bond the laminates overmore » the course of 1 to 18 hours. Laminates consist of layers of glass or other materials bonded with vinyl or urethane interlayers. In autoclaving, significant heat energy is lost heating the chamber, pressurized air, glass racks, and the glass. In RF lamination, the heat is generated directly in the vinyl interlayer, causing it to heat and melt quickly, in just 1 to 10 minutes, without significantly heating the glass or the equipment. The main purpose of this project was to provide evidence that low energy, rapid RF lamination quality met the same standards as conventionally autoclaved windows. The development of concepts for laminating curved glass with RF lamination was a major goal. Other primary goals included developing a stronger understanding of the lamination product markets described above, and to refine the potential benefits of commercial implementation. The scope of the project was to complete implementation concept studies in preparation for continuation into advanced development, pilot studies, and commercial implementation. The project consisted of 6 main tasks. The first dealt with lamination with poly-vinyl butyral (PVB) interlayers, which prior work had shown difficulties in achieving good quality laminates, working with Pilkington North America. The second task dealt with a study of current lamination processes in the various laminate industries, and development of concepts for integrating RF lamination into new or existing processes. The third task explored the use of a non-destructive technique for analyzing laminate adhesion with the University of Illinois at Urbana-Champaign. The fourth task focused on developing concepts for curved glass lamination using RF lamination. The fifth and sixth tasks together comprised an analysis of laminate product markets, ranking for applicability and commercialization potential, and the development of commercialization strategies for those products. In addition, throughout the project as new experimental data and conventional process data were obtained, the benefits analysis of RF lamination was refined. The goals of the project described above were achieved, positioning RF lamination for the next stage growth envisioned in the original Industrial Grand Challenge proposal. Working with Pilkington North America, lamination of flat autoglass with PVB was achieved, meeting all 16 stringent industry tests. In particular, PVB laminates made with RF lamination passed environmental tests including the high temperature, 120°C bake test, without significant formation of bubbles (defects). The adhesion of PVB to glass was measured using the pummel method. Adhesion values ranging from 1 to 7 out of 10 were obtained. The significant process parameters affecting the environmental and adhesion performance were identified through a designed experiment. Pre-lamination process variables including PVB storage humidity and the de-airing process (vacuum or nip rolling) were significant, as well as the level of pressure applied to the laminate during the RF process. Analysis of manufacturing with RF lamination equipment, based on the processes developed indicated that 3 RF presses could replace a typical auto-industry autoclave to achieve equal or greater throughput with possibly less capital cost and smaller footprint. Concepts for curved lamination identifying castable molds for prototyping were developed, which allowed Ceralink to obtain commitment to begin curved tooling development. The project significantly helped to advance RF lamination past the feasibility and novelty stage and into the realm of commercial acceptance as a viable alternative to autoclaves. The demonstration of autoclave-quality autoglass produced in just 1 minute with RF lamination, with validation by Pilkington, has fueled industry motivation to seriously consider RF lamination. The industry and other contacts and outreach made in the study of laminate markets (including 3 technical publications and 5 conference presentations), has resulted in a recent surge in RF lamination activity.« less

Energy Saving Glass Lamination via Selective Radio Frequency Heating

DOE Office of Scientific and Technical Information (OSTI.GOV)

Allan, Shawn M.

2012-02-27

This project focused on advancing radio-frequency (RF) lamination technology closer to commercial implementation, in order to reduce the energy intensity of glass lamination by up to 90%. Lamination comprises a wide range of products including autoglass, architectural safety and innovative design glass, transparent armor (e.g. bullet proof glass), smart glass, mirrors, and encapsulation of photovoltaics. Lamination is also the fastest growing segment of glass manufacturing, with photovoltaics, architectural needs, and an anticipated transition to laminated side windows in vehicles. The state-of-the-art for glass lamination is to use autoclaves, which apply heat and uniform gas pressure to bond the laminates overmore » the course of 1 to 18 hours. Laminates consist of layers of glass or other materials bonded with vinyl or urethane interlayers. In autoclaving, significant heat energy is lost heating the chamber, pressurized air, glass racks, and the glass. In RF lamination, the heat is generated directly in the vinyl interlayer, causing it to heat and melt quickly, in just 1 to 10 minutes, without significantly heating the glass or the equipment. The main purpose of this project was to provide evidence that low energy, rapid RF lamination quality met the same standards as conventionally autoclaved windows. The development of concepts for laminating curved glass with RF lamination was a major goal. Other primary goals included developing a stronger understanding of the lamination product markets described above, and to refine the potential benefits of commercial implementation. The scope of the project was to complete implementation concept studies in preparation for continuation into advanced development, pilot studies, and commercial implementation. The project consisted of 6 main tasks. The first dealt with lamination with poly-vinyl butyral (PVB) interlayers, which prior work had shown difficulties in achieving good quality laminates, working with Pilkington North America. The second task dealt with a study of current lamination processes in the various laminate industries, and development of concepts for integrating RF lamination into new or existing processes. The third task explored the use of a non-destructive technique for analyzing laminate adhesion with the University of Illinois at Urbana-Champaign. The fourth task focused on developing concepts for curved glass lamination using RF lamination. The fifth and sixth tasks together comprised an analysis of laminate product markets, ranking for applicability and commercialization potential, and the development of commercialization strategies for those products. In addition, throughout the project as new experimental data and conventional process data were obtained, the benefits analysis of RF lamination was refined. The goals of the project described above were achieved, positioning RF lamination for the next stage growth envisioned in the original Industrial Grand Challenge proposal. Working with Pilkington North America, lamination of flat autoglass with PVB was achieved, meeting all 16 stringent industry tests. In particular, PVB laminates made with RF lamination passed environmental tests including the high temperature, 120 C bake test, without significant formation of bubbles (defects). The adhesion of PVB to glass was measured using the pummel method. Adhesion values ranging from 1 to 7 out of 10 were obtained. The significant process parameters affecting the environmental and adhesion performance were identified through a designed experiment. Pre-lamination process variables including PVB storage humidity and the de-airing process (vacuum or nip rolling) were significant, as well as the level of pressure applied to the laminate during the RF process. Analysis of manufacturing with RF lamination equipment, based on the processes developed indicated that 3 RF presses could replace a typical auto-industry autoclave to achieve equal or greater throughput with possibly less capital cost and smaller footprint. Concepts for curved lamination identifying castable molds for prototyping were developed, which allowed Ceralink to obtain commitment to begin curved tooling development. The project significantly helped to advance RF lamination past the feasibility and novelty stage and into the realm of commercial acceptance as a viable alternative to autoclaves. The demonstration of autoclave-quality autoglass produced in just 1 minute with RF lamination, with validation by Pilkington, has fueled industry motivation to seriously consider RF lamination. The industry and other contacts and outreach made in the study of laminate markets (including 3 technical publications and 5 conference presentations), has resulted in a recent surge in RF lamination activity.« less

44. HISTORIC VIEW LOOKING WEST AT THE TEST STAND AND ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

44. HISTORIC VIEW LOOKING WEST AT THE TEST STAND AND ROCKET BEING PREPARED FOR TESTING. NOTE THE LOAD CELL APPARATUS ABOVE THE ROCKET AND THE EQUIPMENT PLATFORM TO THE LEFT OF THE LOAD CELL HAVE BEEN ENCLOSED FOR PROTECTION FROM THE CLIMATE. - Marshall Space Flight Center, Redstone Rocket (Missile) Test Stand, Dodd Road, Huntsville, Madison County, AL

36. HISTORIC GENERAL VIEW LOOKING NORTH DOWN THE FLAME TRENCH ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

36. HISTORIC GENERAL VIEW LOOKING NORTH DOWN THE FLAME TRENCH AT THE TEST STAND. NOTE THE MOTORIZED LIFT TO THE LEFT OF THE TEST STAND, USED TO ACCESS THE INSTRUMENTATION PLATFORM ('BIRDCAGE') MOUNTED ON TOP OF THE ROCKET DURING TEST FIRINGS. - Marshall Space Flight Center, Redstone Rocket (Missile) Test Stand, Dodd Road, Huntsville, Madison County, AL

Saturn Apollo Program

NASA Image and Video Library

1967-01-01

This photograph is a view of the Saturn V S-IC (first) test stage being hoisted into the S-IC-B1 test stand at the Mississippi Test Facility (MTF), Bay St. Louis, Mississippi. This stage was used to prove the operational readiness of the stand. Begirning operations in 1966, the MTF has two test stands; a dual-position structure for running the S-IC stage at full throttle, and two separate stands for the S-II (Saturn V third) stage. It became the focus of the static test firing program. The completed S-IC stage was shipped from the Michoud Assembly Facility (MAF) to the MTF. The stage was then installed into the 124-meter-high test stand for static firing tests before shipment to the Kennedy Space Center for final assembly of the Saturn V vehicle. The MTF was renamed to the National Space Technology Laboratory (NSTL) in 1974 and later to the Stennis Space Center (SSC) in May 1988.

Credit WCT. Photographic copy of photograph, view of Test Stand ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Credit WCT. Photographic copy of photograph, view of Test Stand "D" from the south with tower ejector system in operation during a 1972 engine test. Note steam evolving from Z-stage ejectors atop the interstage condenser in the tower. Note also the "Hyprox" steam generator straddling the Dd ejector train to the right. The new Dy horizontal train has not been erected as of this date. In the distance is Test Stand "E." (JPL negative no. 384-9766-AC, 28 November 1972) - Jet Propulsion Laboratory Edwards Facility, Test Stand D, Edwards Air Force Base, Boron, Kern County, CA

Development of sub-100 femtosecond timing and synchronization system

NASA Astrophysics Data System (ADS)

Lin, Zhenyang; Du, Yingchao; Yang, Jin; Xu, Yilun; Yan, Lixin; Huang, Wenhui; Tang, Chuanxiang; Huang, Gang; Du, Qiang; Doolittle, Lawrence; Wilcox, Russell; Byrd, John

2018-01-01

The precise timing and synchronization system is an essential part for the ultra-fast electron and X-ray sources based on the photocathode injector where strict synchronization among RF, laser, and beams are required. In this paper, we present an integrated sub-100 femtosecond timing and synchronization system developed and demonstrated recently in Tsinghua University based on the collaboration with Lawrence Berkeley National Lab. The timing and synchronization system includes the fiber-based CW carrier phase reference distribution system for delivering stabilized RF phase reference to multiple receiver clients, the Low Level RF (LLRF) control system to monitor and generate the phase and amplitude controllable pulse RF signal, and the laser-RF synchronization system for high precision synchronization between optical and RF signals. Each subsystem is characterized by its blocking structure and is also expansible. A novel asymmetric calibration sideband signal method was proposed for eliminating the non-linear distortion in the optical synchronization process. According to offline and online tests, the system can deliver a stable signal to each client and suppress the drift and jitter of the RF signal for the accelerator and the laser oscillator to less than 100 fs RMS (˜0.1° in 2856 MHz frequency). Moreover, a demo system with a LLRF client and a laser-RF synchronization client is deployed and operated successfully at the Tsinghua Thomson scattering X-ray source. The beam-based jitter measurement experiments have been conducted to evaluate the overall performance of the system, and the jitter sources are discussed.

Development of sub-100 femtosecond timing and synchronization system.

PubMed

Lin, Zhenyang; Du, Yingchao; Yang, Jin; Xu, Yilun; Yan, Lixin; Huang, Wenhui; Tang, Chuanxiang; Huang, Gang; Du, Qiang; Doolittle, Lawrence; Wilcox, Russell; Byrd, John

2018-01-01

The precise timing and synchronization system is an essential part for the ultra-fast electron and X-ray sources based on the photocathode injector where strict synchronization among RF, laser, and beams are required. In this paper, we present an integrated sub-100 femtosecond timing and synchronization system developed and demonstrated recently in Tsinghua University based on the collaboration with Lawrence Berkeley National Lab. The timing and synchronization system includes the fiber-based CW carrier phase reference distribution system for delivering stabilized RF phase reference to multiple receiver clients, the Low Level RF (LLRF) control system to monitor and generate the phase and amplitude controllable pulse RF signal, and the laser-RF synchronization system for high precision synchronization between optical and RF signals. Each subsystem is characterized by its blocking structure and is also expansible. A novel asymmetric calibration sideband signal method was proposed for eliminating the non-linear distortion in the optical synchronization process. According to offline and online tests, the system can deliver a stable signal to each client and suppress the drift and jitter of the RF signal for the accelerator and the laser oscillator to less than 100 fs RMS (∼0.1° in 2856 MHz frequency). Moreover, a demo system with a LLRF client and a laser-RF synchronization client is deployed and operated successfully at the Tsinghua Thomson scattering X-ray source. The beam-based jitter measurement experiments have been conducted to evaluate the overall performance of the system, and the jitter sources are discussed.

2D modeling of DC potential structures induced by RF sheaths with transverse currents in front of ICRF antenna

NASA Astrophysics Data System (ADS)

Faudot, E.; Heuraux, S.; Colas, L.

2005-09-01

Understanding DC potential generation in front of ICRF antennas is crucial for long pulse high RF power systems. DC potentials are produced by sheath rectification of these RF potentials. To reach this goal, near RF parallel electric fields have to be computed in 3D and integrated along open magnetic field lines to yield a 2D RF potential map in a transverse plane. DC potentials are produced by sheath rectification of these RF potentials. As RF potentials are spatially inhomogeneous, transverse polarization currents are created, modifying RF and DC maps. Such modifications are quantified on a `test map' having initially a Gaussian shape and assuming that the map remains Gaussian near its summit,the time behavior of the peak can be estimated analytically in presence of polarization current as a function of its width r0 and amplitude φ0 (normalized to a characteristic length for transverse transport and to the local temperature). A `peaking factor' is built from the DC peak potential normalized to φ0, and validated with a 2D fluid code and a 2D PIC code (XOOPIC). In an unexpected way transverse currents can increase this factor. Realistic situations of a Tore Supra antenna are also studied, with self-consistent near fields provided by ICANT code. Basic processes will be detailed and an evaluation of the `peaking factor' for ITER will be presented for a given configuration.

2D modeling of DC potential structures induced by RF sheaths with transverse currents in front of ICRF antenna

DOE Office of Scientific and Technical Information (OSTI.GOV)

Faudot, E.; Heuraux, S.; Colas, L.

2005-09-26

Understanding DC potential generation in front of ICRF antennas is crucial for long pulse high RF power systems. DC potentials are produced by sheath rectification of these RF potentials. To reach this goal, near RF parallel electric fields have to be computed in 3D and integrated along open magnetic field lines to yield a 2D RF potential map in a transverse plane. DC potentials are produced by sheath rectification of these RF potentials. As RF potentials are spatially inhomogeneous, transverse polarization currents are created, modifying RF and DC maps. Such modifications are quantified on a 'test map' having initially amore » Gaussian shape and assuming that the map remains Gaussian near its summit,the time behavior of the peak can be estimated analytically in presence of polarization current as a function of its width r0 and amplitude {phi}0 (normalized to a characteristic length for transverse transport and to the local temperature). A 'peaking factor' is built from the DC peak potential normalized to {phi}0, and validated with a 2D fluid code and a 2D PIC code (XOOPIC). In an unexpected way transverse currents can increase this factor. Realistic situations of a Tore Supra antenna are also studied, with self-consistent near fields provided by ICANT code. Basic processes will be detailed and an evaluation of the 'peaking factor' for ITER will be presented for a given configuration.« less

TEST STAND 4697 CONSTRUCTION

NASA Image and Video Library

2016-01-06

A CRANE MOVES THE FIRST STEEL TIER TO BE BOLTED INTO PLACE ON JAN. 6, FOR WELDING OF A SECOND NEW STRUCTURAL TEST STAND AT NASA'S MARSHALL SPACE FLIGHT CENTER IN HUNTSVILLE, ALABAMA -- CRITICAL TO DEVELOPMENT OF NASA'S SPACE LAUNCH SYSTEM. WHEN COMPLETED THIS SUMMER, THE 85-FOOT-TALL TEST STAND 4697 WILL USE HYDRAULIC CYLINDERS TO SUBJECT THE LIQUID OXYGEN TANK AND HARDWARE OF THE MASSIVE SLS CORE STAGE TO THE SAME LOADS AND STRESSES IT WILL ENDURE DURING A LAUNCH. THE STAND IS RISING IN MARSHALL'S WEST TEST AREA, WHERE WORK IS ALSO UNDERWAY ON THE 215-FOOT-TALL TOWERS OF TEST STAND 4693, WHICH WILL CONDUCT SIMILAR STRUCTURAL TESTS ON THE SLS CORE STAGE'S LIQUID HYDROGEN TANK. SLS, THE MOST POWERFUL ROCKET EVER BUILT, WILL CARRY ASTRONAUTS IN NASA'S ORION SPACECRAFT ON DEEP SPACE MISSIONS, INCLUDING THE JOURNEY TO MARS.

TMS delivered for A-3 Test Stand

NASA Image and Video Library

2010-03-17

A state-of-the-art thrust measurement system for the A-3 Test Stand under construction at NASA's John C. Stennis Space Center was delivered March 17. Once completed, the A-3 stand (seen in background) will allow simulated high-altitude testing on the next generation of rocket engines for America's space program. Work on the stand began in 2007, with activation scheduled for 2012. The stand is the first major test structure to be built at Stennis since the 1960s. The recently delivered TMS was fabricated by Thrust Measurement Systems in Illinois. It is an advanced calibration system capable of measuring vertical and horizontal thrust loads with an accuracy within 0.15 percent at 225,000 pounds.

Credit BG. View west of Test Stand "D" complex, with ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Credit BG. View west of Test Stand "D" complex, with ends of Dd (left) and Dy (right) station ejectors in view. Steam piping from accumulator (sphere) to ejectors is apparent; long horizontal loops in the pipes permit expansion and contraction without special joints. The small platform straddling the Dd ejector (near the accumulator) was originally constructed for a "Hyprox" steam generator which supplied steam to the Dd ejector before the accumulator and Dy stand were built. Note ejectors on top of interstage condenser in Test Stand "D" tower. Metal shed in far right background is for storage - Jet Propulsion Laboratory Edwards Facility, Test Stand D, Edwards Air Force Base, Boron, Kern County, CA

Qualification of UHF Antenna for Extreme Martian Thermal Environments

NASA Technical Reports Server (NTRS)

Ramesham, Rajeshuni; Amaro, Luis R.; Brown, Paula R.; Usiskin, Robert

2013-01-01

The purpose of this development was to validate the use of the external Rover Ultra High Frequency (RUHF) antenna for space under extreme thermal environments to be encountered during the surface operations of the Mars Science Laboratory (MSL) mission. The antenna must survive all ground operations plus the nominal 670 Martian sol mission that includes summer and winter seasons of the Mars thermal environment.The qualification effort was to verify that the RUHF antenna design and its bonding and packaging processes are adequate to survive the harsh environmental conditions. The RUHF is a quadrifilar helix antenna mounted on the MSL Curiosity rover deck. The main components of the RUHF antenna are the helix structure, feed cables, and hybrid coupler, and the high-power termination load. In the case of MSL rover externally mounted hardware, not only are the expected thermal cycle depths severe, but there are temperature offsets between the Mars summer and winter seasons. The total number of temperature cycles needed to be split into two regimes of summer cycles and winter cycles. The qualification test was designed to demonstrate a survival life of three times more than all expected ground testing, plus a nominal 670 Martian sol missions. Baseline RF tests and a visual inspection were performed prior to the start of the qualification test. Functional RF tests were performed intermittently during chamber breaks over the course of the qualification test. For the RF return loss measurements, the antenna was tested in a controlled environment outside the thermal chamber with a vector network analyzer that was calibrated over the antenna s operational frequency range. A total of 2,010 thermal cycles were performed. Visual inspection showed a dulling of the solder material. This change will not affect the performance of the antenna. No other changes were observed. RF tests were performed on the RUHF helix antenna, hybrid, and load after the 2,010 qualification cycles test. The RF performance of the RUHF antenna, hybrid, and load were almost identical before and after the complete test. Therefore, the developed design of RUHF is qualified for a long-duration MSL mission. The RUHF antenna has not been used for long-duration missions such as MSL in the past. The state-of-the-art technology of the RUHF antenna is used to develop the antennas for MSL mission survivability. This developmental test data provides the confidence in using this RUHF antenna for future NASA missions to Mars.

Around Marshall

NASA Image and Video Library

1963-02-04

At its founding, the Marshall Space Flight Center (MSFC) inherited the Army’s Jupiter and Redstone test stands, but much larger facilities were needed for the giant stages of the Saturn V. From 1960 to 1964, the existing stands were remodeled and a sizable new test area was developed. The new comprehensive test complex for propulsion and structural dynamics was unique within the nation and the free world, and they remain so today because they were constructed with foresight to meet the future as well as on going needs. Construction of the S-IC Static test stand complex began in 1961 in the west test area of MSFC, and was completed in 1964. The S-IC static test stand was designed to develop and test the 138-ft long and 33-ft diameter Saturn V S-IC first stage, or booster stage, weighing in at 280,000 pounds. Required to hold down the brute force of a 7,500,000-pound thrust produced by 5 F-1 engines, the S-IC static test stand was designed and constructed with the strength of hundreds of tons of steel and 12,000,000 pounds of cement, planted down to bedrock 40 feet below ground level. The foundation walls, constructed with concrete and steel, are 4 feet thick. The base structure consists of four towers with 40-foot-thick walls extending upward 144 feet above ground level. The structure was topped by a crane with a 135-foot boom. With the boom in the upright position, the stand was given an overall height of 405 feet, placing it among the highest structures in Alabama at the time. In addition to the stand itself, related facilities were constructed during this time. Built directly east of the test stand was the Block House, which served as the control center for the test stand. The two were connected by a narrow access tunnel which housed the cables for the controls. This photograph taken February 4, 1963, gives an impressive look at the Block House looking directly through the ever-growing four towers of the S-IC Test Stand.