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Sample records for acquisition single-shot turbo

  1. Quantitative analysis of the breath-holding half-Fourier acquisition single-shot turbo spin-echo technique in abdominal MRI

    NASA Astrophysics Data System (ADS)

    Dong, Kyung-Rae; Goo, Eun-Hoe; Lee, Jae-Seung; Chung, Woon-Kwan

    2013-01-01

    A consecutive series of 50 patients (28 males and 22 females) who underwent hepatic magnetic resonance imaging (MRI) from August to December 2011 were enrolled in this study. The appropriate parameters for abdominal MRI scans were determined by comparing the images (TE = 90 and 128 msec) produced using the half-Fourier acquisition single-shot turbo spin-echo (HASTE) technique at different signal acquisition times. The patients consisted of 15 normal patients, 25 patients with a hepatoma and 10 patients with a hemangioma. The TE in a single patient was set to either 90 msec or 128 msec. This was followed by measurements using the four normal rendering methods of the biliary tract system and the background signal intensity using the maximal signal intensity techniques in the liver, spleen, pancreas, gallbladder, fat, muscles and hemangioma. The signal-to-noise and the contrast-to-noise ratios were obtained. The image quality was assessed subjectively, and the results were compared. The signal-to-noise and the contrast-to-noise ratios were significantly higher at TE = 128 msec than at TE = 90 when diseases of the liver, spleen, pancreas, gallbladder, and fat and muscles, hepatocellular carcinomas and hemangiomas, and rendering the hepatobiliary tract system based on the maximum signal intensity technique were involved (p < 0.05). In addition, the presence of artifacts, the image clarity and the overall image quality were excellent at TE = 128 msec (p < 0.05). In abdominal MRI, the breath-hold half-Fourier acquisition single-shot turbo spin-echo (HASTE) was found to be effective in illustrating the abdominal organs for TE = 128 msec. Overall, the image quality at TE = 128 msec was better than that at TE = 90 msec due to the improved signal-to-noise (SNR) and contrast-to-noise (CNR) ratios. Overall, the HASTE technique for abdominal MRI based on a high-magnetic field (3.0 T) at a TE of 128 msec can provide useful data.

  2. Diffusion-weighted imaging in the prostate: an apparent diffusion coefficient comparison of half-Fourier acquisition single-shot turbo spin-echo and echo planar imaging.

    PubMed

    Babourina-Brooks, Ben; Cowin, Gary J; Wang, Deming

    2012-02-01

    Prostate cancer detection using diffusion-weighted imaging is highly affected by the accuracy of the apparent diffusion coefficient (ADC) values in an image. Echo planar imaging (EPI) is a fast sequence commonly used for diffusion imaging but has inherent magnetic susceptibility and chemical shift artefacts associated. A diffusion sequence that is less affected by these artefacts is therefore advantageous. The half-Fourier acquisition single-shot turbo spin-echo (HASTE) sequence was chosen. The diffusion sequences were compared in image quality, repeatability of the ADC value and the effect on the ADC value with varied b values. Eight volunteers underwent three scans of each sequence, on a 1.5-T Siemens system, using b values of 0, 150, 300, 450, 600, 750, 900 and 1000 s/mm(2). ADC maps were created to address the reproducibility of the ADC value when using two b values compared to eight b values. The ADC value using all b values with the HASTE sequence gave the best performance in all tested categories. Both sequences gave significantly different ADC mean values for two b values compared to when using eight b values (P<.05) suggesting larger error is present when using two b values. HASTE was shown to be an improvement over EPI in terms of repeatability, signal variation within a region of interest and standard deviation over the volunteer set. The improved accuracy of the ADC value in the HASTE sequence makes it potentially a more sensitive tumor detection technique.

  3. Value of a single-shot turbo spin-echo pulse sequence for assessing the architecture of the subarachnoid space and the constitutive nature of cerebrospinal fluid.

    PubMed

    Pease, Anthony; Sullivan, Stacey; Olby, Natasha; Galano, Heather; Cerda-Gonzalez, Sophia; Robertson, Ian D; Gavin, Patrick; Thrall, Donald

    2006-01-01

    Three case history reports are presented to illustrate the value of the single-shot turbo spin-echo pulse sequence for assessment of the subarachnoid space. The use of the single-shot turbo spin-echo pulse sequence, which is a heavily T2-weighted sequence, allows for a rapid, noninvasive evaluation of the subarachnoid space by using the high signal from cerebrospinal fluid. This sequence can be completed in seconds rather than the several minutes required for a T2-fast spin-echo sequence. Unlike the standard T2-fast spin-echo sequence, a single-shot turbo spin-echo pulse sequence also provides qualitative information about the protein and the cellular content of the cerebrospinal fluid, such as in patients with inflammatory debris or hemorrhage in the cerebrospinal fluid. Although the resolution of the single-shot turbo spin-echo pulse sequence images is relatively poor compared with more conventional sequences, the qualitative information about the subarachnoid space and cerebrospinal fluid and the rapid acquisition time, make it a useful sequence to include in standard protocols of spinal magnetic resonance imaging.

  4. SINGLE-SHOT TURBO SPIN ECHO PULSE SEQUENCE FINDINGS IN DOGS WITH AND WITHOUT PROGRESSIVE MYELOMALACIA.

    PubMed

    Gilmour, Lindsey J; Jeffery, Nick D; Miles, Kristina; Riedesel, Elizabeth

    2017-03-01

    Progressive myelomalacia is an uncommon type of ischemic, hemorrhagic spinal cord infarction. Diagnosis can be difficult, but prompt recognition is important. We hypothesized that cerebrospinal fluid signal attenuation on magnetic resonance (MR) images would be more extensive in dogs that developed progressive myelomalacia vs. control dogs. A retrospective analytic cohort study was designed. Dogs were included if they presented for acute paraplegia and loss of deep pain perception and had undergone MR imaging using both sagittal single-shot turbo spin echo (SSTSE) and standard sagittal T2-weighted fast spin echo (T2W) pulse sequences. Dogs were divided into progressive myelomalacia and control groups for comparisons. All MR examinations were evaluated by three reviewers blinded to patient outcome. Length of cerebrospinal fluid attenuation was recorded as a ratio to the length of the L2 vertebral body in SSTSE and T2W sequences (CSF:L2SSTSE and CSF:L2T2 , respectively). Length of intramedullary spinal cord hyperintensity was recorded as a ratio to the length of the L2 vertebral body in T2W sequences. A total of 21 dogs were included (five in the progressive myelomalacia group and 16 in the control group). The mean CSF:L2SSTSE attenuation value was significantly higher in dogs that developed progressive myelomalacia (CSF:L2SSTSE = 10.7) compared to controls (CSF:L2SSTSE = 5.4; P = 0.015). A cut off ratio of attenuation >7.4 provided optimal differentiation between groups in this study. Findings supported the conclusion that dogs with CSF:L2SSTSE ≤ 7.4 are unlikely to develop progressive myelomalacia while dogs with CSF:L2SSTSE > 7.4 are indeterminate for progressive myelomalacia.

  5. Breath-hold black blood quantitative T1rho imaging of liver using single shot fast spin echo acquisition

    PubMed Central

    Chan, Queenie; Wáng, Yì-Xiáng J.

    2016-01-01

    Background Liver fibrosis is a key feature in most chronic liver diseases. T1rho magnetic resonance imaging is a potentially important technique for noninvasive diagnosis, severity grading, and therapy monitoring of liver fibrosis. However, it remains challenging to perform robust T1rho quantification of liver on human subjects. One major reason is that the presence of rich blood signal in liver can cause artificially high T1rho measurement and makes T1rho quantification susceptible to motion. Methods A pulse sequence based on single shot fast/turbo spin echo (SSFSE/SSTSE) acquisition, with theoretical analysis and simulation based on the extended phase graph (EPG) algorithm, was presented for breath-hold single slice quantitative T1rho imaging of liver with suppression of blood signal. The pulse sequence was evaluated in human subjects at 3.0 T with 500 Hz spinlock frequency and time-of-spinlock (TSL) 0, 10, 30 and 50 ms. Results Human scan demonstrated that the entire T1rho data sets with four spinlock time can be acquired within a single breath-hold of 10 seconds with black blood effect. T1rho quantification with suppression of blood signal results in significantly reduced T1rho value of liver compared to the results without blood suppression. Conclusions A signal-to-noise ratio (SNR) efficient pulse sequence was reported for T1rho quantification of liver. The black blood effect, together with a short breath-hold, mitigates the risk of quantification errors as would occur in the conventional methods. PMID:27190769

  6. Reference-free unwarping of single-shot spatiotemporally encoded MRI using asymmetric self-refocused echoes acquisition

    NASA Astrophysics Data System (ADS)

    Chen, Ying; Chen, Song; Zhong, Jianhui; Chen, Zhong

    2015-05-01

    This paper presents a phase evolution rewinding algorithm for correcting the geometric and intensity distortions in single-shot spatiotemporally encoded (SPEN) MRI with acquisition of asymmetric self-refocused echo trains. Using the field map calculated from the phase distribution of the source image, the off-resonance induced phase errors are successfully rewound through deconvolution. The alias-free partial Fourier transform reconstruction helps improve the signal-to-noise ratio of the field maps and the output images. The effectiveness of the proposed algorithm was validated through 7 T MRI experiments on a lemon, a water phantom, and in vivo rat head. SPEN imaging was evaluated using rapid acquisition by sequential excitation and refocusing (RASER) which produces uniform T2 weighting. The results indicate that the new technique can more robustly deal with the cases in which the images obtained with conventional single-shot spin-echo EPI are difficult to be restored due to serious field variations.

  7. Single-shot acquisition of optical direct and global components using single coded pattern projection

    NASA Astrophysics Data System (ADS)

    Ando, Takamasa; Horisaki, Ryoichi; Nakamura, Tomoya; Tanida, Jun

    2015-04-01

    We present a single-shot approach for separating optical direct and global components from an object. The former component is caused by direct illumination that travels from a light source to a point on the object and goes back to a camera directly. The latter one is caused by indirect illumination that travels from the light source to a point on the object through other points and goes back to the camera, such as multi-path reflection, diffusion, and scattering, or from another unintended light source, such as ambient illumination. In this method, the direct component is modulated by a single coded pattern from a projector. The modulated direct and un-modulated global components are integrated on an image sensor, which captures a single image. These two components are separated from the single captured image with a numerical algorithm employing a sparsity constraint. Ambient light separation and descattering based on the proposed scheme are experimentally demonstrated.

  8. A single-shot, multiwavelength electro-optic data-acquisition system for inertial confinement fusion applications (invited).

    PubMed

    Donaldson, W R; Zhao, C; Ji, L; Roides, R G; Miller, K; Beeman, B

    2012-10-01

    Electro-optic data-acquisition systems encode the output from voltage-history diagnostics onto optical signals. The optical signals can propagate long distances over fiber-optic links without degrading the bandwidth of the encoded signal while protecting the recording electronics from overvoltage damage. The sinusoidal response and tolerance to high-input voltages of the Mach-Zehnder modulator used for the encoding leads to the additional advantage of a high dynamic range and a reduced need for manually swapping attenuators. We have demonstrated a single-shot, electro-optic data-acquisition system with a 600:1 dynamic range. This system provides optical isolation and a bandwidth of 6 GHz. The prototype system uses multiple optical wavelengths to allow for the multiplexing of up to eight signals onto one photodetector.

  9. A single-shot, multiwavelength electro-optic data-acquisition system for inertial confinement fusion applications (invited)

    SciTech Connect

    Donaldson, W. R.; Zhao, C.; Ji, L.; Roides, R. G.; Miller, K.; Beeman, B.

    2012-10-15

    Electro-optic data-acquisition systems encode the output from voltage-history diagnostics onto optical signals. The optical signals can propagate long distances over fiber-optic links without degrading the bandwidth of the encoded signal while protecting the recording electronics from overvoltage damage. The sinusoidal response and tolerance to high-input voltages of the Mach-Zehnder modulator used for the encoding leads to the additional advantage of a high dynamic range and a reduced need for manually swapping attenuators. We have demonstrated a single-shot, electro-optic data-acquisition system with a 600:1 dynamic range. This system provides optical isolation and a bandwidth of 6 GHz. The prototype system uses multiple optical wavelengths to allow for the multiplexing of up to eight signals onto one photodetector.

  10. High-Acquisition-Rate Single-Shot Pump-Probe Measurements Using Time-Stretching Method

    PubMed Central

    Kobayashi, Masataka; Minami, Yasuo; Johnson, Courtney L.; Salmans, Parker D.; Ellsworth, Nicholas R.; Takeda, Jun; Johnson, Jeremy A.; Katayama, Ikufumi

    2016-01-01

    Recent advances of ultrafast spectroscopy allow the capture of an entire ultrafast signal waveform in a single probe shot, which greatly reduces the measurement time and opens the door for the spectroscopy of unrepeatable phenomena. However, most single-shot detection schemes rely on two-dimensional detectors, which limit the repetition rate of the measurement and can hinder real-time visualization and manipulation of signal waveforms. Here, we demonstrate a new method to circumvent these difficulties and to greatly simplify the detection setup by using a long, single-mode optical fiber and a fast photodiode. Initially, a probe pulse is linearly chirped (the optical frequency varies linearly across the pulse in time), and the temporal profile of an ultrafast signal is then encoded in the probe spectrum. The probe pulse and encoded temporal dynamics are further chirped to nanosecond time scales using the dispersion in the optical fiber, thus, slowing down the ultrafast signal to time scales easily recorded with fast detectors and high-bandwidth electronics. We apply this method to three distinct ultrafast experiments: investigating the power dependence of the Kerr signal in LiNbO3, observing an irreversible transmission change of a phase change material, and capturing terahertz waveforms. PMID:27876881

  11. High-Acquisition-Rate Single-Shot Pump-Probe Measurements Using Time-Stretching Method

    NASA Astrophysics Data System (ADS)

    Kobayashi, Masataka; Minami, Yasuo; Johnson, Courtney L.; Salmans, Parker D.; Ellsworth, Nicholas R.; Takeda, Jun; Johnson, Jeremy A.; Katayama, Ikufumi

    2016-11-01

    Recent advances of ultrafast spectroscopy allow the capture of an entire ultrafast signal waveform in a single probe shot, which greatly reduces the measurement time and opens the door for the spectroscopy of unrepeatable phenomena. However, most single-shot detection schemes rely on two-dimensional detectors, which limit the repetition rate of the measurement and can hinder real-time visualization and manipulation of signal waveforms. Here, we demonstrate a new method to circumvent these difficulties and to greatly simplify the detection setup by using a long, single-mode optical fiber and a fast photodiode. Initially, a probe pulse is linearly chirped (the optical frequency varies linearly across the pulse in time), and the temporal profile of an ultrafast signal is then encoded in the probe spectrum. The probe pulse and encoded temporal dynamics are further chirped to nanosecond time scales using the dispersion in the optical fiber, thus, slowing down the ultrafast signal to time scales easily recorded with fast detectors and high-bandwidth electronics. We apply this method to three distinct ultrafast experiments: investigating the power dependence of the Kerr signal in LiNbO3, observing an irreversible transmission change of a phase change material, and capturing terahertz waveforms.

  12. Method and device for measuring single-shot transient signals

    DOEpatents

    Yin, Yan

    2004-05-18

    Methods, apparatus, and systems, including computer program products, implementing and using techniques for measuring multi-channel single-shot transient signals. A signal acquisition unit receives one or more single-shot pulses from a multi-channel source. An optical-fiber recirculating loop reproduces the one or more received single-shot optical pulses to form a first multi-channel pulse train for circulation in the recirculating loop, and a second multi-channel pulse train for display on a display device. The optical-fiber recirculating loop also optically amplifies the first circulating pulse train to compensate for signal losses and performs optical multi-channel noise filtration.

  13. Single-shot T1 mapping using simultaneous acquisitions of spin- and stimulated-echo-planar imaging (2D ss-SESTEPI).

    PubMed

    Shi, Xianfeng; Kim, Seong-Eun; Jeong, Eun-Kee

    2010-09-01

    The conventional stimulated-echo NMR sequence only measures the longitudinal component while discarding the transverse component, after tipping up the prepared magnetization. This transverse magnetization can be used to measure a spin echo, in addition to the stimulated echo. Two-dimensional single-shot spin- and stimulated-echo-planar imaging (ss-SESTEPI) is an echo-planar-imaging-based single-shot imaging technique that simultaneously acquires a spin-echo-planar image and a stimulated-echo-planar image after a single radiofrequency excitation. The magnitudes of the spin-echo-planar image and stimulated-echo-planar image differ by T(1) decay and diffusion weighting for perfect 90 degrees radiofrequency and thus can be used to rapidly measure T(1). However, the spatial variation of amplitude of radiofrequency field induces uneven splitting of the transverse magnetization for the spin-echo-planar image and stimulated-echo-planar image within the imaging field of view. Correction for amplitude of radiofrequency field inhomogeneity is therefore critical for two-dimensional ss-SESTEPI to be used for T(1) measurement. We developed a method for amplitude of radiofrequency field inhomogeneity correction by acquiring an additional stimulated-echo-planar image with minimal mixing time, calculating the difference between the spin echo and the stimulated echo and multiplying the stimulated-echo-planar image by the inverse functional map. Diffusion-induced decay is corrected by measuring the average diffusivity during the prescanning. Rapid single-shot T(1) mapping may be useful for various applications, such as dynamic T(1) mapping for real-time estimation of the concentration of contrast agent in dynamic contrast enhancement MRI.

  14. Development of a single-shot CCD-based data acquisition system for time-resolved X-ray photoelectron spectroscopy at an X-ray free-electron laser facility.

    PubMed

    Oura, Masaki; Wagai, Tatsuya; Chainani, Ashish; Miyawaki, Jun; Sato, Hiromi; Matsunami, Masaharu; Eguchi, Ritsuko; Kiss, Takayuki; Yamaguchi, Takashi; Nakatani, Yasuhiro; Togashi, Tadashi; Katayama, Tetsuo; Ogawa, Kanade; Yabashi, Makina; Tanaka, Yoshihito; Kohmura, Yoshiki; Tamasaku, Kenji; Shin, Shik; Ishikawa, Tetsuya

    2014-01-01

    In order to utilize high-brilliance photon sources, such as X-ray free-electron lasers (XFELs), for advanced time-resolved photoelectron spectroscopy (TR-PES), a single-shot CCD-based data acquisition system combined with a high-resolution hemispherical electron energy analyzer has been developed. The system's design enables it to be controlled by an external trigger signal for single-shot pump-probe-type TR-PES. The basic performance of the system is demonstrated with an offline test, followed by online core-level photoelectron and Auger electron spectroscopy in 'single-shot image', 'shot-to-shot image (image-to-image storage or block storage)' and `shot-to-shot sweep' modes at soft X-ray undulator beamline BL17SU of SPring-8. In the offline test the typical repetition rate for image-to-image storage mode has been confirmed to be about 15 Hz using a conventional pulse-generator. The function for correcting the shot-to-shot intensity fluctuations of the exciting photon beam, an important requirement for the TR-PES experiments at FEL sources, has been successfully tested at BL17SU by measuring Au 4f photoelectrons with intentionally controlled photon flux. The system has also been applied to hard X-ray PES (HAXPES) in `ordinary sweep' mode as well as shot-to-shot image mode at the 27 m-long undulator beamline BL19LXU of SPring-8 and also at the SACLA XFEL facility. The XFEL-induced Ti 1s core-level spectrum of La-doped SrTiO3 is reported as a function of incident power density. The Ti 1s core-level spectrum obtained at low power density is consistent with the spectrum obtained using the synchrotron source. At high power densities the Ti 1s core-level spectra show space-charge effects which are analysed using a known mean-field model for ultrafast electron packet propagation. The results successfully confirm the capability of the present data acquisition system for carrying out the core-level HAXPES studies of condensed matter induced by the XFEL.

  15. Single shot line-field optical coherence elastography

    NASA Astrophysics Data System (ADS)

    Liu, Chih-Hao; Schill, Alexander; Singh, Manmohan; Wu, Chen; Li, Jiasong; Han, Zhaolong; Raghunathan, Raksha; Kazemi, Tina; Nair, Achuth; Hsu, Thomas; Larin, Kirill V.

    2016-03-01

    Elastic wave imaging optical coherence elastography (EWI-OCE) is an emerging technique that can quantify local biomechanical properties of tissues. However, long acquisition times make this technique unfeasible for clinical use. Here, we demonstrate a noncontact single shot line-field OCE technique using a line-field interferometer and an air-pulse delivery system. The spatial-temporal elastic wave propagation profile was acquired in a single shot and used to quantify the elastic wave group velocity in tissue. Results on tissue-mimicking phantoms and chicken breast muscle agreed well with mechanical compression testing, demonstrating that the presented method can effectively reduce the OCE acquisition time to a few milliseconds in biological application.

  16. Validation of V-SS-PARSE for single-shot flow measurement.

    PubMed

    Zuo, Jin; Bolding, Mark; Twieg, Donald B

    2007-04-01

    As a variant of Single-Shot Parameter Assessment by Retrieval from Signal Encoding, Velocity Single-Shot Parameter Assessment by Retrieval from Signal Encoding, a single-shot imaging method, has been developed to realize fast and straightforward flow quantification by solving inverse problems. A robust signal model, including its local magnetization and its phase evolution during signaling (resulting in a more precise representation of the sampled signal) is described here. Magnitude, velocity, relaxation rate and frequency information can be retrieved without any extra reference image acquisitions, as demonstrated by phantom studies. In the presence of stationary background, retrieved magnitude maps and velocity maps show results comparable to those obtained by phase-contrast methods (r>.99, P=.005), even with brief single-shot 70-ms acquisition.

  17. Ultrafast single-shot measurement of optical Kerr effect based on supercontinuum pulse.

    PubMed

    Zhang, Jian; Liu, Shenye; Yi, Tao; Wu, Xingzhi; Song, Yinglin; Zhang, Ben; Zhong, Quanjie

    2016-04-01

    We present an ultrafast single-shot measurement method for the optical Kerr effect based on a polarization gating technique. The advantages of this single-shot technique are demonstrated via a 26-ps chirped supercontinuum pulse used to measure the optical Kerr effect for three transparent organic liquids. The single-shot measurement results agree well with those of the time-resolved optical Kerr gate method, as regards both time and intensity. This method facilitates real-time observation of ultrafast optical Kerr responses of samples and simultaneous high-time-resolution data acquisition at ∼260 fs. We demonstrate that the single-shot measurement method is potentially a powerful tool for investigating the optical Kerr effects of unstable samples, and for application to high-power laser systems.

  18. Single shot interferogram analysis for optical metrology.

    PubMed

    Singh, Mahendra Pratap; Singh, Mandeep; Khare, Kedar

    2014-10-10

    We report a novel constrained optimization method for single shot interferogram analysis. The unknown test wavefront is estimated as a minimum L2-norm squared solution whose phase is constrained to the space spanned by a finite number of Zernike polynomials. Using a single frame from standard phase shifting datasets, we demonstrate that our approach provides a phase map that matches with that generated using phase shifting algorithms to within λ/100  rms error. Our simulations and experimental results suggest the possibility of a simplified low-cost high quality optical metrology system for performing routine metrology tests involving smooth surface profiles.

  19. Single-shot curved slice imaging.

    PubMed

    Jochimsen, Thies H; Norris, David G

    2002-03-01

    The feasibility of imaging a curved slice with a single-shot technique so that the reconstructed image shows an un-warping of the slice is examined. This could be of practical importance when the anatomical structures of interest can be more efficiently covered with curved slices than with a series of flat planes. One possible example of such a structure is the cortex of the human brain. Functional imaging would especially benefit from this technique because several planar images can be replaced by a few curved slice images. A method is introduced that is based on multidimensional pulses to excite the desired curved slice profile. A GRASE imaging sequence is then applied that is tailored to the k-space representation of the curved slice. This makes it possible to capture the in-plane information of the slice with a single-shot technique. The method presented is limited to slices that are straight along one axis and can be approximated by a polygon. Reconstruction is performed using a simple numeric Fourier integration along the curved slice. This leads to an image that shows the desired un-warped representation of the slice. Experimental results obtained with this method from healthy volunteers are presented and demonstrate the feasibility of the proposed technique.

  20. Single shot ptychographical iterative engine based on multi-beam illumination

    NASA Astrophysics Data System (ADS)

    Pan, Xingchen; Liu, Cheng; Zhu, Jianqiang

    2013-10-01

    An optical alignment and a corresponding reconstruction algorithm are proposed to realize a single shot Ptychographical Iterative Engine (PIE). Multiple light beams generated by a cross grating are used to illuminate the specimen, and the resulting diffraction patterns formed on the detector plane by each beam are recorded simultaneously. The modulus and phase images are properly reconstructed with standard PIE algorithm. The proposed single shot method omits the needs for a mechanical x-y scanning of standard PIE algorithm and hence dramatically reduces the data acquisition time.

  1. Single-Shot H(2) Cars Spectroscopy of Propellant Ignition and Combustion under Pressure.

    DTIC Science & Technology

    1986-05-01

    accurate thermometry. intensity -determination in an unreferenced fashion reveals fluctuations of 30Z, with con- tributions from YAG and dye laser...background gas, flow rates through the pres- sure cell, YAG laser fluence, and dye laser spectral width are critical factors in the development of a...and Detection Optics 4 Detection of CARS; Data Acquisition Logic 5 Test Procedures 5 Results and Discussion 7 Triggerable, Single-Shot CARS

  2. Single-shot and phase-shifting digital holographic microscopy using a 2-D grating.

    PubMed

    Yang, Taeseok Daniel; Kim, Hyung-Jin; Lee, Kyoung J; Kim, Beop-Min; Choi, Youngwoon

    2016-05-02

    We demonstrate digital holographic microscopy that, while being based on phase-shifting interferometry, is capable of single-shot measurements. A two-dimensional (2-D) diffraction grating placed in a Fourier plane of a standard in-line holographic phase microscope generates multiple copies of a sample image on a camera sensor. The identical image copies are spatially separated with different overall phase shifts according to the diffraction orders. The overall phase shifts are adjusted by controlling the lateral position of the grating. These phase shifts are then set to be multiples of π/2. Interferograms composed of four image copies combined with a parallel reference beam are acquired in a single shot. The interferograms are processed through a phase-shifting algorithm to produce a single complex image. By taking advantage of the higher sampling capacity of the in-line holography, we can increase the imaging information density by a factor of 3 without compromising the imaging acquisition speed.

  3. Single-shot low coherence pointwise measuring interferometer with potential for in-line inspection

    NASA Astrophysics Data System (ADS)

    Hahn, R.; Krauter, J.; Körner, K.; Gronle, M.; Osten, W.

    2017-02-01

    Low-coherence-interferometry (LCI) is a well-known optical metrology technique which offers high resolution and a low measurement uncertainty. For the inspection of dynamic and fast processes, single-shot point sensors can show their full capability. Therefore, a new approach of an interferometer is presented, allowing an single-shot acquisition of a LCI signal. The presented concept is based on tilted wavefronts to generate a spatial modulated interferogram. Using a three faceted mirror (TFM) in the reference path, a virtual field point is generated leading to a tilted planar reference wavefront in the pupil plane of the telecentric objective lens. Three mirror surfaces, which are diamond milled out of a monolithic copper cube, are applied to guarantee a stable TFM geometry, resulting in an invariant reference field point position.

  4. Single-shot positron annihilation lifetime spectroscopy with LYSO scintillators

    NASA Astrophysics Data System (ADS)

    Alonso, A. M.; Cooper, B. S.; Deller, A.; Cassidy, D. B.

    2016-08-01

    We have evaluated the application of a lutetium yttrium oxyorthosilicate (LYSO) based detector to single-shot positron annihilation lifetime spectroscopy. We compare this detector directly with a similarly configured PbWO4 scintillator, which is the usual choice for such measurements. We find that the signal to noise ratio obtained using LYSO is around three times higher than that obtained using PbWO4 for measurements of Ps excited to longer-lived (Rydberg) levels, or when they are ionized soon after production. This is due to the much higher light output for LYSO (75% and 1% of NaI for LYSO and PbWO4 respectively). We conclude that LYSO is an ideal scintillator for single-shot measurements of positronium production and excitation performed using a low-intensity pulsed positron beam.

  5. Single shot cell irradiations with laser-driven protons

    SciTech Connect

    Humble, N.; Schmid, T. E.; Zlobinskaya, O.; Wilkens, J. J.; Allinger, K.; Hilz, P.; Ma, W.; Reinhardt, S.; Bin, J.; Kiefer, D.; Schreiber, J.; Drexler, G. A.; Friedl, A.

    2013-07-26

    Ion beams are relevant for radiobiological studies in basic research and for application in tumor therapy. Here we present a method to generate nanosecond proton bunches with single shot doses of up to 7 Gray by a tabletop high-power laser. Although in their infancy, laser-ion accelerators allow studying fast radiobiological processes at small-scale laboratories as exemplarily demonstrated by measurements of the relative biological effectiveness of protons in human tumor cells.

  6. Single-shot fluctuations in waveguided high-harmonic generation.

    PubMed

    Goh, S J; Tao, Y; van der Slot, P J M; Bastiaens, H J M; Herek, J; Biedron, S G; Danailov, M B; Milton, S V; Boller, K-J

    2015-09-21

    For exploring the application potential of coherent soft x-ray (SXR) and extreme ultraviolet radiation (XUV) provided by high-harmonic generation, it is important to characterize the central output parameters. Of specific importance are pulse-to-pulse (shot-to-shot) fluctuations of the high-harmonic output energy, fluctuations of the direction of the emission (pointing instabilities), and fluctuations of the beam divergence and shape that reduce the spatial coherence. We present the first single-shot measurements of waveguided high-harmonic generation in a waveguided (capillary-based) geometry. Using a capillary waveguide filled with Argon gas as the nonlinear medium, we provide the first characterization of shot-to-shot fluctuations of the pulse energy, of the divergence and of the beam pointing. We record the strength of these fluctuations vs. two basic input parameters, which are the drive laser pulse energy and the gas pressure in the capillary waveguide. In correlation measurements between single-shot drive laser beam profiles and single-shot high-harmonic beam profiles we prove the absence of drive laser beam-pointing-induced fluctuations in the high-harmonic output. We attribute the main source of high-harmonic fluctuations to ionization-induced nonlinear mode mixing during propagation of the drive laser pulse inside the capillary waveguide.

  7. Non-contact single shot elastography using line field low coherence holography

    PubMed Central

    Liu, Chih-Hao; Schill, Alexander; Wu, Chen; Singh, Manmohan; Larin, Kirill V.

    2016-01-01

    Optical elastic wave imaging is a powerful technique that can quantify local biomechanical properties of tissues. However, typically long acquisition times make this technique unfeasible for clinical use. Here, we demonstrate non-contact single shot elastographic holography using a line-field interferometer integrated with an air-pulse delivery system. The propagation of the air-pulse induced elastic wave was imaged in real time, and required a single excitation for a line-scan measurement. Results on tissue-mimicking phantoms and chicken breast muscle demonstrated the feasibility of this technique for accurate assessment of tissue biomechanical properties with an acquisition time of a few milliseconds using parallel acquisition. PMID:27570694

  8. Single-shot camera position estimation by crossed grating imaging

    NASA Astrophysics Data System (ADS)

    Juarez-Salazar, Rigoberto; Gaxiola, Leopoldo N.; Diaz-Ramirez, Victor H.

    2017-01-01

    A simple method to estimate the position of a camera device with respect to a reference plane is proposed. The method utilizes a crossed grating in the reference plane and exploits the coordinate transformation induced by the perspective projection. If the focal length is available, the position of the camera can be estimated with a single-shot. Otherwise, the focal length can be firstly estimated from few frames captured at different known displacements. The theoretical principles of the proposed method are given and the functionality of the approach is exhibited by correcting perspective-distorted images. The proposed method is computationally efficient and highly appropriate to be used in dynamic measurement systems.

  9. Single-shot phase-measuring deflectometry for cornea measurement

    NASA Astrophysics Data System (ADS)

    Liang, Hanning; Olesch, Evelyn; Yang, Zheng; Häusler, Gerd

    2016-12-01

    Phase-measuring deflectometry (PMD) has become a standard tool to measure the topography of specular surfaces. We implemented PMD for the measurement of the human cornea topography, exploiting an earlier idea of Lingelbach et al. Two problems occur: a large angular dynamical range and a single-shot measurement are required. We solve these problems by an optimized geometry with minimal occlusion and by single sideband demodulation with a pre-distorted fringe pattern with optimal fringe period. An in vivo measurement of an astigmatic cornea displays a deviation from the medical diagnosis of only 0.15 D, which is within the medical quantization step of 0.25 D.

  10. Single-Shot Fault-Tolerant Quantum Error Correction

    NASA Astrophysics Data System (ADS)

    Bombín, Héctor

    2015-07-01

    Conventional quantum error correcting codes require multiple rounds of measurements to detect errors with enough confidence in fault-tolerant scenarios. Here, I show that for suitable topological codes, a single round of local measurements is enough. This feature is generic and is related to self-correction and confinement phenomena in the corresponding quantum Hamiltonian model. Three-dimensional gauge color codes exhibit this single-shot feature, which also applies to initialization and gauge fixing. Assuming the time for efficient classical computations to be negligible, this yields a topological fault-tolerant quantum computing scheme where all elementary logical operations can be performed in constant time.

  11. Single-shot and single-sensor high/super-resolution microwave imaging based on metasurface

    PubMed Central

    Wang, Libo; Li, Lianlin; Li, Yunbo; Zhang, Hao Chi; Cui, Tie Jun

    2016-01-01

    Real-time high-resolution (including super-resolution) imaging with low-cost hardware is a long sought-after goal in various imaging applications. Here, we propose broadband single-shot and single-sensor high-/super-resolution imaging by using a spatio-temporal dispersive metasurface and an imaging reconstruction algorithm. The metasurface with spatio-temporal dispersive property ensures the feasibility of the single-shot and single-sensor imager for super- and high-resolution imaging, since it can convert efficiently the detailed spatial information of the probed object into one-dimensional time- or frequency-dependent signal acquired by a single sensor fixed in the far-field region. The imaging quality can be improved by applying a feature-enhanced reconstruction algorithm in post-processing, and the desired imaging resolution is related to the distance between the object and metasurface. When the object is placed in the vicinity of the metasurface, the super-resolution imaging can be realized. The proposed imaging methodology provides a unique means to perform real-time data acquisition, high-/super-resolution images without employing expensive hardware (e.g. mechanical scanner, antenna array, etc.). We expect that this methodology could make potential breakthroughs in the areas of microwave, terahertz, optical, and even ultrasound imaging. PMID:27246668

  12. Single-shot and single-sensor high/super-resolution microwave imaging based on metasurface

    NASA Astrophysics Data System (ADS)

    Wang, Libo; Li, Lianlin; Li, Yunbo; Zhang, Hao Chi; Cui, Tie Jun

    2016-06-01

    Real-time high-resolution (including super-resolution) imaging with low-cost hardware is a long sought-after goal in various imaging applications. Here, we propose broadband single-shot and single-sensor high-/super-resolution imaging by using a spatio-temporal dispersive metasurface and an imaging reconstruction algorithm. The metasurface with spatio-temporal dispersive property ensures the feasibility of the single-shot and single-sensor imager for super- and high-resolution imaging, since it can convert efficiently the detailed spatial information of the probed object into one-dimensional time- or frequency-dependent signal acquired by a single sensor fixed in the far-field region. The imaging quality can be improved by applying a feature-enhanced reconstruction algorithm in post-processing, and the desired imaging resolution is related to the distance between the object and metasurface. When the object is placed in the vicinity of the metasurface, the super-resolution imaging can be realized. The proposed imaging methodology provides a unique means to perform real-time data acquisition, high-/super-resolution images without employing expensive hardware (e.g. mechanical scanner, antenna array, etc.). We expect that this methodology could make potential breakthroughs in the areas of microwave, terahertz, optical, and even ultrasound imaging.

  13. Single-shot measurement of soot aggregate sizes by wide-angle light scattering (WALS)

    NASA Astrophysics Data System (ADS)

    Oltmann, H.; Reimann, J.; Will, S.

    2012-01-01

    The wide-angle light scattering (WALS) approach has been utilized for the measurement of soot aggregate sizes (radii of gyration) in flames on a single-shot basis. Key elements are a pulsed laser and an ellipsoidal mirror, which images the light scattered within a plane onto an intensified CCD camera, thus allowing for an instantaneous acquisition of a full scattering diagram with high resolution. Results for a laminar premixed flame exhibit good agreement with averaged data and demonstrate the feasibility of the method. The applicability of the technique to unsteady combustion processes is demonstrated by measuring aggregate sizes in a weakly turbulent jet-diffusion flame. In both cases light scattering results are verified by data obtained from electron microscopy analysis of sampled soot.

  14. Dispersive Fourier transformation for fast continuous single-shot measurements

    NASA Astrophysics Data System (ADS)

    Goda, K.; Jalali, B.

    2013-02-01

    Dispersive Fourier transformation is an emerging measurement technique that overcomes the speed limitations of traditional optical instruments and enables fast continuous single-shot measurements in optical sensing, spectroscopy and imaging. Using chromatic dispersion, dispersive Fourier transformation maps the spectrum of an optical pulse to a temporal waveform whose intensity mimics the spectrum, thus allowing a single-pixel photodetector to capture the spectrum at a scan rate significantly beyond what is possible with conventional space-domain spectrometers. Over the past decade, this method has brought us a new class of real-time instruments that permit the capture of rare events such as optical rogue waves and rare cancer cells in blood, which would otherwise be missed using conventional instruments. In this Review, we discuss the principle of dispersive Fourier transformation and its implementation across a wide range of diverse applications.

  15. Terahertz single-shot quadrature phase-shifting interferometry.

    PubMed

    Földesy, Péter

    2012-10-01

    A single-shot quadrature phase-shifting interferometry architecture is presented that is applicable to antenna coupled detector technologies. The method is based on orthogonally polarized object and reference beams and on linear and circular polarization sensitive antennas in space-division multiplexing. The technique can be adapted to two-, three-, and four-step and Gabor holography recordings. It is also demonstrated that the space-division multiplexing does not necessarily cause sparse sampling. A sub-THz detector array is presented containing multiple on-chip antennas and FET plasma wave detectors implemented in a 90 nm complementary metal-oxide semiconductor technology. As an example, two-step phase-shifting reconstruction results are given at 360 GHz.

  16. Single-shot ultrafast tomographic imaging by spectral multiplexing

    NASA Astrophysics Data System (ADS)

    Matlis, N. H.; Axley, A.; Leemans, W. P.

    2012-10-01

    Computed tomography has profoundly impacted science, medicine and technology by using projection measurements scanned over multiple angles to permit cross-sectional imaging of an object. The application of computed tomography to moving or dynamically varying objects, however, has been limited by the temporal resolution of the technique, which is set by the time required to complete the scan. For objects that vary on ultrafast timescales, traditional scanning methods are not an option. Here we present a non-scanning method capable of resolving structure on femtosecond timescales by using spectral multiplexing of a single laser beam to perform tomographic imaging over a continuous range of angles simultaneously. We use this technique to demonstrate the first single-shot ultrafast computed tomography reconstructions and obtain previously inaccessible structure and position information for laser-induced plasma filaments. This development enables real-time tomographic imaging for ultrafast science, and offers a potential solution to the challenging problem of imaging through scattering surfaces.

  17. Single-shot ultrafast tomographic imaging by spectral multiplexing.

    PubMed

    Matlis, N H; Axley, A; Leemans, W P

    2012-01-01

    Computed tomography has profoundly impacted science, medicine and technology by using projection measurements scanned over multiple angles to permit cross-sectional imaging of an object. The application of computed tomography to moving or dynamically varying objects, however, has been limited by the temporal resolution of the technique, which is set by the time required to complete the scan. For objects that vary on ultrafast timescales, traditional scanning methods are not an option. Here we present a non-scanning method capable of resolving structure on femtosecond timescales by using spectral multiplexing of a single laser beam to perform tomographic imaging over a continuous range of angles simultaneously. We use this technique to demonstrate the first single-shot ultrafast computed tomography reconstructions and obtain previously inaccessible structure and position information for laser-induced plasma filaments. This development enables real-time tomographic imaging for ultrafast science, and offers a potential solution to the challenging problem of imaging through scattering surfaces.

  18. Nonadiabatic holonomic gates realized by a single-shot implementation

    NASA Astrophysics Data System (ADS)

    Xu, G. F.; Liu, C. L.; Zhao, P. Z.; Tong, D. M.

    2015-11-01

    Nonadiabatic holonomic quantum computation has received increasing attention due to its robustness against control errors. However, all the previous schemes have to use at least two sequentially implemented gates to realize a general one-qubit gate. In this paper we put forward a scheme by which one can directly realize an arbitrary holonomic one-qubit gate with a single-shot implementation, avoiding the extra work of combining two gates into one. Based on a three-level model driven by laser pulses, we show that any single-qubit holonomic gate can be realized by varying the detuning, amplitude, and phase of lasers. Our scheme is compatible with previously proposed nonadiabatic holonomic two-qubit gates, combining with which the arbitrary holonomic one-qubit gates can play universal nonadiabatic holonomic quantum computation. We also investigate the effects of some unavoidable realistic errors on our scheme.

  19. In vivo single-shot 13C spectroscopic imaging of hyperpolarized metabolites by spatiotemporal encoding

    NASA Astrophysics Data System (ADS)

    Schmidt, Rita; Laustsen, Christoffer; Dumez, Jean-Nicolas; Kettunen, Mikko I.; Serrao, Eva M.; Marco-Rius, Irene; Brindle, Kevin M.; Ardenkjaer-Larsen, Jan Henrik; Frydman, Lucio

    2014-03-01

    Hyperpolarized metabolic imaging is a growing field that has provided a new tool for analyzing metabolism, particularly in cancer. Given the short life times of the hyperpolarized signal, fast and effective spectroscopic imaging methods compatible with dynamic metabolic characterizations are necessary. Several approaches have been customized for hyperpolarized 13C MRI, including CSI with a center-out k-space encoding, EPSI, and spectrally selective pulses in combination with spiral EPI acquisitions. Recent studies have described the potential of single-shot alternatives based on spatiotemporal encoding (SPEN) principles, to derive chemical-shift images within a sub-second period. By contrast to EPSI, SPEN does not require oscillating acquisition gradients to deliver chemical-shift information: its signal encodes both spatial as well as chemical shift information, at no extra cost in experimental complexity. SPEN MRI sequences with slice-selection and arbitrary excitation pulses can also be devised, endowing SPEN with the potential to deliver single-shot multi-slice chemical shift images, with a temporal resolution required for hyperpolarized dynamic metabolic imaging. The present work demonstrates this with initial in vivo results obtained from SPEN-based imaging of pyruvate and its metabolic products, after injection of hyperpolarized [1-13C]pyruvate. Multi-slice chemical-shift images of healthy rats were obtained at 4.7 T in the region of the kidney, and 4D (2D spatial, 1D spectral, 1D temporal) data sets were obtained at 7 T from a murine lymphoma tumor model.

  20. Single-shot retinal imaging with AO spectral OCT

    NASA Astrophysics Data System (ADS)

    Zhang, Yan; Rha, Jungtae; Jonnal, Ravi S.; Miller, Donald T.

    2005-04-01

    We demonstrate for the first time an adaptive optics (AO) spectral OCT retina camera that acquires with unprecedented 3D resolution (2.9 μm lateral; 5.5 μm axial) single shot B-scans of the living human retina. The camera centers on a Michelson interferometer that consists of a superluminescent diode for line illuminating the subject's retinal; voice coil translator for controlling the optical path length of the reference channel; and an imaging spectrometer that is cascaded with a 12-bit area CCD array. The imaging spectrometer was designed with negligible off-axis aberrations and was constructed from stock optical components. AO was integrated into the detector channel of the interferometer and dynamically compensated for most of the ocular aberration across a 6 mm pupil. Short bursts of B-scans, with 100 Ascans each, were successfully acquired at 1 msec intervals. Camera sensitivity was found sufficient to detect reflections from all major retinal layers. Individual outer segments of photoreceptors at different retinal eccentricities were observed in vivo. Periodicity of the outer segments matched cone spacing as measured from AO flood illuminated images of the same patches of retina.

  1. Single-shot adaptive measurement for quantum-enhanced metrology

    NASA Astrophysics Data System (ADS)

    Palittpongarnpim, Pantita; Wittek, Peter; Sanders, Barry C.

    2016-09-01

    Quantum-enhanced metrology aims to estimate an unknown parameter such that the precision scales better than the shot-noise bound. Single-shot adaptive quantum-enhanced metrology (AQEM) is a promising approach that uses feedback to tweak the quantum process according to previous measurement outcomes. Techniques and formalism for the adaptive case are quite different from the usual non-adaptive quantum metrology approach due to the causal relationship between measurements and outcomes. We construct a formal framework for AQEM by modeling the procedure as a decision-making process, and we derive the imprecision and the Craḿer- Rao lower bound with explicit dependence on the feedback policy. We also explain the reinforcement learning approach for generating quantum control policies, which is adopted due to the optimal policy being non-trivial to devise. Applying a learning algorithm based on differential evolution enables us to attain imprecision for adaptive interferometric phase estimation, which turns out to be SQL when non-entangled particles are used in the scheme.

  2. Time-resolved single-shot terahertz time-domain spectroscopy for ultrafast irreversible processes

    NASA Astrophysics Data System (ADS)

    Zhai, Zhao-Hui; Zhong, Sen-Cheng; Li, Jun; Zhu, Li-Guo; Meng, Kun; Li, Jiang; Liu, Qiao; Peng, Qi-Xian; Li, Ze-Ren; Zhao, Jian-Heng

    2016-09-01

    Pulsed terahertz spectroscopy is suitable for spectroscopic diagnostics of ultrafast events. However, the study of irreversible or single shot ultrafast events requires ability to record transient properties at multiple time delays, i.e., time resolved at single shot level, which is not available currently. Here by angular multiplexing use of femtosecond laser pulses, we developed and demonstrated a time resolved, transient terahertz time domain spectroscopy technique, where burst mode THz pulses were generated and then detected in a single shot measurement manner. The burst mode THz pulses contain 2 sub-THz pulses, and the time gap between them is adjustable up to 1 ns with picosecond accuracy, thus it can be used to probe the single shot event at two different time delays. The system can detect the sub-THz pulses at 0.1 THz-2.5 THz range with signal to noise ratio (SNR) of ˜400 and spectrum resolution of 0.05 THz. System design was described here, and optimizations of single shot measurement of THz pulses were discussed in detail. Methods to improve SNR were also discussed in detail. A system application was demonstrated where pulsed THz signals at different time delays of the ultrafast process were successfully acquired within single shot measurement. This time resolved transient terahertz time domain spectroscopy technique provides a new diagnostic tool for irreversible or single shot ultrafast events where dynamic information can be extracted at terahertz range within one-shot experiment.

  3. 2D-Omnidirectional Hard-X-Ray Scattering Sensitivity in a Single Shot

    NASA Astrophysics Data System (ADS)

    Kagias, Matias; Wang, Zhentian; Villanueva-Perez, Pablo; Jefimovs, Konstantins; Stampanoni, Marco

    2016-03-01

    X-ray scattering imaging can provide complementary information to conventional absorption based radiographic imaging about the unresolved microstructures of a sample. The scattering signal can be accessed with various methods based on coherent illumination, which span from self-imaging to speckle scanning. The directional sensitivity of the existing real space imaging methods is limited to a few directions on the imaging plane and requires scanning of the optical components, or the rotation of either the sample or the imaging setup, in order to cover the full range of possible scattering directions. In this Letter the authors propose a new method that allows the simultaneous acquisition of scattering images in all possible directions in a single shot. This is achieved by a specialized phase grating and a detector with sufficient spatial resolution to record the generated interference fringe. The structural length scale sensitivity of the system can be tuned by varying its geometry for a fixed grating design. Taking into account ongoing developments in the field of compact x-ray sources that allow high brightness and sufficient spatial coherence, the applicability of omnidirectional scattering imaging in industrial and medical settings is boosted significantly.

  4. Invited Article: Single-shot THz detection techniques optimized for multidimensional THz spectroscopy

    SciTech Connect

    Teo, Stephanie M.; Ofori-Okai, Benjamin K.; Werley, Christopher A.; Nelson, Keith A.

    2015-05-15

    Multidimensional spectroscopy at visible and infrared frequencies has opened a window into the transfer of energy and quantum coherences at ultrafast time scales. For these measurements to be performed in a manageable amount of time, one spectral axis is typically recorded in a single laser shot. An analogous rapid-scanning capability for THz measurements will unlock the multidimensional toolkit in this frequency range. Here, we first review the merits of existing single-shot THz schemes and discuss their potential in multidimensional THz spectroscopy. We then introduce improved experimental designs and noise suppression techniques for the two most promising methods: frequency-to-time encoding with linear spectral interferometry and angle-to-time encoding with dual echelons. Both methods, each using electro-optic detection in the linear regime, were able to reproduce the THz temporal waveform acquired with a traditional scanning delay line. Although spectral interferometry had mediocre performance in terms of signal-to-noise, the dual echelon method was easily implemented and achieved the same level of signal-to-noise as the scanning delay line in only 4.5% of the laser pulses otherwise required (or 22 times faster). This reduction in acquisition time will compress day-long scans to hours and hence provides a practical technique for multidimensional THz measurements.

  5. Towards Single-Shot Detection of Bacterial Endospores via Coherent Raman Spectroscopy

    NASA Astrophysics Data System (ADS)

    Pestov, Dmitry; Wang, Xi; Ariunbold, Gombojav; Murawski, Robert; Sautenkov, Vladimir; Sokolov, Alexei; Scully, Marlan

    2007-10-01

    Recent advances in coherent anti-Stokes Raman scattering (CARS) spectroscopy hold exciting promise to make the most out of now readily available ultrafast laser sources. Techniques have been devised to mitigate the nonresonant four-wave-mixing in favor of informative Raman-resonant signal. In particular, a hybrid technique for CARS (see Science 316, 265 (2007)) brings together the advantages of coherent broadband pump-Stokes excitation of molecular vibrations and their time-delayed but frequency-resolved probing via a spectrally narrowed and shaped laser pulse. We apply this technique to the problem of real-time detection of warfare bioagents and report single-shot acquisition of a distinct CARS spectrum from a small volume of B. subtilis endospores (˜10^4 spores), a harmless surrogate for B. anthracis. We study the dependence of the CARS signal on the energy of the ultrashort preparation pulses and find the limit on the pulse energy fluence (˜0.2 J/cm^2), imposed by the laser-induced damage of the spores.

  6. Three-dimensional single-shot optoacoustic visualization of excised mouse organs with model-based reconstruction

    NASA Astrophysics Data System (ADS)

    Deán-Ben, X. L.; Buehler, Andreas; Ntziachristos, Vasilis; Razansky, Daniel

    2013-03-01

    Optoacoustic imaging offers the unique capability of simultaneous excitation of a three-dimensional (volumetric) region with a single interrogating laser pulse. In this way, three-dimensional imaging with single-shot illumination is theoretically achievable, which in principle allows the visualization of dynamic events at a high frame rate mainly limited by the pulse repetition rate of the laser. Simultaneous acquisition of optoacoustic signals at a set of points surrounding the imaging sample is however required for this purpose, which is hampered by several technical limitations related to lack of appropriate ultrasound detection technology, digital sampling and processing capacities. Also, a convenient reconstruction algorithm must be selected to accurately image the distribution of the optical absorption from the acquired signals. Specifically, the resolution and quantitativeness of the images depend on the reconstruction procedure employed. Herein we describe an accurate three-dimensional model-based optoacoustic reconstruction algorithm based on a convenient discretization of the analytical solution of the forward model. Subsequent algebraic inversion is done with the LSQR algorithm. The performance of the algorithm is showcased by reconstructing an excised mouse heart with a custom made three-dimensional optoacoustic imaging system. In this system, 256 optoacoustic signals corresponding to single-shot excitation are simultaneously collected with an array of ultrasonic transducers disposed on a spherical surface, which allows three-dimensional imaging at a frame rate of 10 Hz.

  7. Variable density sampling and non-Cartesian super-resolved reconstruction for spatiotemporally encoded single-shot MRI

    NASA Astrophysics Data System (ADS)

    Chen, Lin; Huang, Jianpan; Zhang, Ting; Li, Jing; Cai, Congbo; Cai, Shuhui

    2016-11-01

    Spatiotemporally encoded (SPEN) single-shot MRI is an emerging ultrafast technique, which is capable of spatially selective acquisition and reduced field-of-view imaging. Compared to uniform sampling, variable density sampling has great potential in reducing aliasing artifacts and improving sampling efficiency. In this study, variable density spiral trajectory and non-Cartesian super-resolved (SR) reconstruction method are developed for SPEN MRI. The gradient waveforms design of spiral trajectory is mathematically described as an optimization problem subjected to the limitations of hardware. Non-Cartesian SR reconstruction with specific gridding method is developed to retrieve a resolution enhanced image from raw SPEN data. The robustness and efficiency of the proposed methods are demonstrated by numerical simulation and various experiments. The results indicate that variable density SPEN MRI can provide better spatial resolution and fewer aliasing artifacts compared to Cartesian counterpart. The proposed methods will facilitate the development of variable density SPEN MRI.

  8. Pulsed second order field NMR for real time PGSE and single-shot surface to volume ratio measurements.

    PubMed

    Kittler, W C; Obruchkov, S; Galvosas, P; Hunter, M W

    2014-10-01

    Pulsed field gradient nuclear magnetic resonance provides a powerful tool for the measurement of particle diffusion and mobility. When these particles are contained in a porous medium, the diffusive process is influenced by the pore boundaries, and their effect on diffusion measurements provides information about the pore space. The acquisition of the apparent diffusion coefficient and its dependence on time, in the short time limit, reveals the surface to volume ratio of the porous medium, and in the long time limit, its tortuosity. With conventional pulsed field gradient techniques, processes where pore boundaries are evolving on the sub-second time scale cannot be resolved. Using pulsed second order magnetic fields in conjunction with one-dimensional imaging and the pulse sequence Difftrain, this paper presents a proof of concept for the first ever real time single-shot surface to volume NMR measurement.

  9. Variable density sampling and non-Cartesian super-resolved reconstruction for spatiotemporally encoded single-shot MRI.

    PubMed

    Chen, Lin; Huang, Jianpan; Zhang, Ting; Li, Jing; Cai, Congbo; Cai, Shuhui

    2016-11-01

    Spatiotemporally encoded (SPEN) single-shot MRI is an emerging ultrafast technique, which is capable of spatially selective acquisition and reduced field-of-view imaging. Compared to uniform sampling, variable density sampling has great potential in reducing aliasing artifacts and improving sampling efficiency. In this study, variable density spiral trajectory and non-Cartesian super-resolved (SR) reconstruction method are developed for SPEN MRI. The gradient waveforms design of spiral trajectory is mathematically described as an optimization problem subjected to the limitations of hardware. Non-Cartesian SR reconstruction with specific gridding method is developed to retrieve a resolution enhanced image from raw SPEN data. The robustness and efficiency of the proposed methods are demonstrated by numerical simulation and various experiments. The results indicate that variable density SPEN MRI can provide better spatial resolution and fewer aliasing artifacts compared to Cartesian counterpart. The proposed methods will facilitate the development of variable density SPEN MRI.

  10. Single shot transverse emittance measurement from OTR screens in a drift transport section

    NASA Astrophysics Data System (ADS)

    Thomas, C.; Delerue, N.; Bartolini, R.

    2011-07-01

    Single shot transverse emittance measurement is essential to assess the beam quality and performance of new generation light sources such as linac based X-ray Free Electron Lasers (FELs) or laser plasma wakefield accelerators (LPWA). To this end, we have developed a single shot transverse emittance measurement using at least 3 screens inserted in the beam at the same time, measuring the beam size at different positions in a drift space in one single shot. In this paper, we firstly present the theoretical aspects to perform the measurement. We secondly show experimental results obtained at Diamond for a 3 GeV electron beam in the transfer line from the Booster to the Storage Ring, using this thin OTR screens method. Finally, we discuss the results showing the strength of the measurement in comparison with more standard and established emittance measurement, like the quadrupole scan method.

  11. High-Fidelity Single-Shot Toffoli Gate via Quantum Control.

    PubMed

    Zahedinejad, Ehsan; Ghosh, Joydip; Sanders, Barry C

    2015-05-22

    A single-shot Toffoli, or controlled-controlled-not, gate is desirable for classical and quantum information processing. The Toffoli gate alone is universal for reversible computing and, accompanied by the Hadamard gate, forms a universal gate set for quantum computing. The Toffoli gate is also a key ingredient for (nontopological) quantum error correction. Currently Toffoli gates are achieved by decomposing into sequentially implemented single- and two-qubit gates, which require much longer times and yields lower overall fidelities compared to a single-shot implementation. We develop a quantum-control procedure to construct a single-shot Toffoli gate for three nearest-neighbor-coupled superconducting transmon systems such that the fidelity is 99.9% and is as fast as an entangling two-qubit gate under the same realistic conditions. The gate is achieved by a nongreedy quantum control procedure using our enhanced version of the differential evolution algorithm.

  12. Single-shot compressed ultrafast photography at one hundred billion frames per second

    NASA Astrophysics Data System (ADS)

    Gao, Liang; Liang, Jinyang; Li, Chiye; Wang, Lihong V.

    2014-12-01

    The capture of transient scenes at high imaging speed has been long sought by photographers, with early examples being the well known recording in 1878 of a horse in motion and the 1887 photograph of a supersonic bullet. However, not until the late twentieth century were breakthroughs achieved in demonstrating ultrahigh-speed imaging (more than 105 frames per second). In particular, the introduction of electronic imaging sensors based on the charge-coupled device (CCD) or complementary metal-oxide-semiconductor (CMOS) technology revolutionized high-speed photography, enabling acquisition rates of up to 107 frames per second. Despite these sensors' widespread impact, further increasing frame rates using CCD or CMOS technology is fundamentally limited by their on-chip storage and electronic readout speed. Here we demonstrate a two-dimensional dynamic imaging technique, compressed ultrafast photography (CUP), which can capture non-repetitive time-evolving events at up to 1011 frames per second. Compared with existing ultrafast imaging techniques, CUP has the prominent advantage of measuring an x-y-t (x, y, spatial coordinates; t, time) scene with a single camera snapshot, thereby allowing observation of transient events with temporal resolution as tens of picoseconds. Furthermore, akin to traditional photography, CUP is receive-only, and so does not need the specialized active illumination required by other single-shot ultrafast imagers. As a result, CUP can image a variety of luminescent--such as fluorescent or bioluminescent--objects. Using CUP, we visualize four fundamental physical phenomena with single laser shots only: laser pulse reflection and refraction, photon racing in two media, and faster-than-light propagation of non-information (that is, motion that appears faster than the speed of light but cannot convey information). Given CUP's capability, we expect it to find widespread applications in both fundamental and applied sciences, including biomedical

  13. Single-shot polarization-imaging digital holography based on simultaneous phase-shifting interferometry.

    PubMed

    Tahara, Tatsuki; Awatsuji, Yasuhiro; Shimozato, Yuki; Kakue, Takashi; Nishio, Kenzo; Ura, Shogo; Kubota, Toshihiro; Matoba, Osamu

    2011-08-15

    We propose single-shot digital holography which is capable of simultaneously capturing both the information of multiple phase-shifted holograms and the distribution of the polarization. In this technique, a single image sensor records both the information required for phase-shifting interferometry and that of the polarization states of objects using an array of polarizers. The essence of the technique is the capability of imaging the distribution of the polarization of three-dimensional objects with a single-shot exposure by using the space-division multiplexing of holograms. The validity of the proposed technique was confirmed by the preliminary experiments.

  14. Single-shot self-interference incoherent digital holography using off-axis configuration

    PubMed Central

    Hong, Jisoo; Kim, Myung K.

    2015-01-01

    We propose a single-shot incoherent holographic imaging technique that adopts self-interference incoherent digital holography (SIDH) with slight tilt of the plane mirror in the optical configuration. The limited temporal coherence length of the illumination leads the guide-star hologram of the proposed system to have a Gaussian envelope of elliptical ring shape. The observation shows that the reconstruction by cross correlation with the guide-star hologram achieves better quality than the usual propagation methods. Experimentally, we verify that the hologram and 3D reconstruction can be implemented incoherently with the proposed single-shot off-axis SIDH. PMID:24281544

  15. Diffusion tensor imaging using single-shot SENSE-EPI.

    PubMed

    Bammer, Roland; Auer, Martin; Keeling, Stephen L; Augustin, Michael; Stables, Lara A; Prokesch, Rupert W; Stollberger, Rudolf; Moseley, Michael E; Fazekas, Franz

    2002-07-01

    SENSitivity Encoding (SENSE) greatly enhances the quality of diffusion-weighted echo-planar imaging (EPI) by reducing blurring and off-resonance artifacts. Such improvement would also be desirable for diffusion tensor imaging (DTI), but measures derived from the diffusion tensor can be extremely sensitive to any kind of image distortion. Whether DTI is feasible in combination with SENSE has not yet been explored, and is the focus of this study. Using a SENSE-reduction factor of 2, DTI scans in eight healthy volunteers were carried out with regular- and high-resolution acquisition matrices. To further improve the stability of the SENSE reconstruction, a new coil-sensitivity estimation technique based on variational calculus and the principles of matrix regularization was applied. With SENSE, maps of the trace of the diffusion tensor and of fractional anisotropy (FA) had improved spatial resolution and less geometric distortion. Overall, the geometric distortions were substantially removed and a significant resolution enhancement was achieved with almost the same scan time as regular EPI. DTI was even possible without the use of quadrature body coil (QBC) reference scans. Geometry-factor-related noise enhancement was only discernible in maps generated with higher-resolution matrices. Error boundaries for residual fluctuations in SENSE reconstructions are discussed. Our results suggest that SENSE can be combined with DTI and may present an important adjunct for future neuroimaging applications of this technique.

  16. Quiescent-Inflow Single-Shot (QISS) Magnetic Resonance Angiography using a Highly Undersampled Radial K-Space Trajectory

    PubMed Central

    Edelman, RR; Giri, S; Dunkle, E; Galizia, M; Amin, P; Koktzoglou, I

    2012-01-01

    Purpose We hypothesized that high undersampling factors could be used in conjunction with radial Quiescent-Inflow Single-Shot (QISS) MRA in order to accelerate the data acquisition and enable multi-slice acquisitions. Methods Seven subjects were imaged on a 1.5T MRI system. For multi-slice QISS MRA, the venous saturation RF pulse, in-plane saturation RF pulse, and QI were applied only once prior to the first slice. Results The mean (standard deviation) measurements for the intra-arterial signal-to-noise ratio were: Cartesian 1 slice - 29.3(5.5); Radial 1 slice, 92 views - 22.3(3.6); Radial 1 slice, 46 views - 18.5(2.0); Radial 2 slices, 46 views - 18.3(3.2); Radial 3 slices, 32 views - 21.7(3.9), normalized for pixel size to 15.8. Horizontal striping was present with multi-slice radial QISS MRA (especially with the 3-slice acquisition) due to variable T1 relaxation between the concurrently acquired slices, but the image quality remained diagnostic. Vascular pathology in patients with peripheral arterial disease was well shown by all techniques. Conclusion Very high undersampling factors in excess of 18 have been demonstrated for nonenhanced MRA using a radial QISS technique, enabling the acquisition of 2 to 3 slices per cardiac cycle. Scan time for a complete peripheral MRA could be shortened to 2 minutes or less. PMID:23348595

  17. Reducing Contrast Contamination in Radial Turbo-Spin-Echo Acquisitions by Combining a Narrow-Band KWIC Filter With Parallel Imaging

    PubMed Central

    Neumann, Daniel; Breuer, Felix A.; Völker, Michael; Brandt, Tobias; Griswold, Mark A.; Jakob, Peter M.; Blaimer, Martin

    2014-01-01

    Purpose Cartesian turbo spin-echo (TSE) and radial TSE images are usually reconstructed by assembling data containing different contrast information into a single k-space. This approach results in mixed contrast contributions in the images, which may reduce their diagnostic value. The goal of this work is to improve the image contrast from radial TSE acquisitions by reducing the contribution of signals with undesired contrast information. Methods Radial TSE acquisitions allow the reconstruction of multiple images with different T2 contrasts using the k-space weighted image contrast (KWIC) filter. In this work, the image contrast is improved by reducing the band-width of the KWIC filter. Data for the reconstruction of a single image are selected from within a small temporal range around the desired echo time. The resulting data set is undersampled and therefore an iterative parallel imaging algorithm is applied to remove aliasing artifacts. Results Radial TSE images of the human brain reconstructed with the proposed method show an improved contrast when compared to Cartesian TSE images or radial TSE images with conventional KWIC reconstructions. Conclusion The proposed method provides multi-contrast images from radial TSE data with contrasts similar to multi spin-echo images. Contaminations from unwanted contrast weightings are strongly reduced. PMID:24436227

  18. Single-shot divergence measurements of a laser-generated relativistic electron beam

    SciTech Connect

    Perez, F.; Baton, S. D.; Koenig, M.; Chen, C. D.; Hey, D.; Key, M. H.; Le Pape, S.; Ma, T.; McLean, H. S.; MacPhee, A. G.; Patel, P. K.; Ping, Y.; Beg, F. N.; Higginson, D. P.; Murphy, C. W.; Sawada, H.; Westover, B.; Yabuuchi, T.; Akli, K. U.; Giraldez, E.

    2010-11-15

    The relativistic electron transport induced by an ultraintense picosecond laser is experimentally investigated using an x-ray two-dimensional imaging system. Previous studies of the electron beam divergence [R. B. Stephens et al. Phys. Rev. E 69, 066414 (2004), for instance] were based on an x-ray imaging of a fluorescence layer buried at different depths in the target along the propagation axis. This technique required several shots to be able to deduce the divergence of the beam. Other experiments produced single-shot images in a one-dimensional geometry. The present paper describes a new target design producing a single-shot, two-dimensional image of the electrons propagating in the target. Several characteristics of the electron beam are extracted and discussed and Monte Carlo simulations provide a good understanding of the observed beam shape. The proposed design has proven to be efficient, reliable, and promising for further similar studies.

  19. Single-Shot Rotational Raman Thermometry for Turbulent Flames Using a Low-Resolution Bandwidth Technique

    NASA Technical Reports Server (NTRS)

    Kojima, Jun; Nguyen, Quang-Viet

    2007-01-01

    An alternative optical thermometry technique that utilizes the low-resolution (order 10(exp 1)/cm) pure-rotational spontaneous Raman scattering of air is developed to aid single-shot multiscalar measurements in turbulent combustion studies. Temperature measurements are realized by correlating the measured envelope bandwidth of the pure-rotational manifold of the N2/O2 spectrum with a theoretical prediction of a species-weighted bandwidth. By coupling this thermometry technique with conventional vibrational Raman scattering for species determination, we demonstrate quantitative spatially resolved, single-shot measurements of the temperature and fuel/oxidizer concentrations in a high-pressure turbulent Cf4-air flame. Our technique provides not only an effective means of validating other temperature measurement methods, but also serves as a secondary thermometry technique in cases where the anti-Stokes vibrational N2 Raman signals are too low for a conventional vibrational temperature analysis.

  20. Single-shot photonic time-intensity integration based on a time-spectrum convolution system.

    PubMed

    Malacarne, Antonio; Ashrafi, Reza; Li, Ming; LaRochelle, Sophie; Yao, Jianping; Azaña, José

    2012-04-15

    Real-time and single-shot ultra-fast photonic time-intensity integration of arbitrary temporal waveforms is proposed and demonstrated. The intensity-integration concept is based on a time-spectrum convolution system, where the use of a multi-wavelength laser with a flat envelope, employed as the incoherent broadband source, enables single-shot operation. The experimental implementation is based on optical intensity modulation of the multi-wavelength laser with the input waveform, followed by linear dispersion. In particular, photonic temporal intensity integration with a processing bandwidth of 36.8 GHz over an integration time window of 1.24 ns is verified by experimentally measuring the integration of an ultra-short microwave pulse and an arbitrary microwave waveform.

  1. Single-shot terahertz time-domain spectroscopy in pulsed high magnetic fields

    NASA Astrophysics Data System (ADS)

    Noe, G. Timothy; Katayama, Ikufumi; Katsutani, Fumiya; Allred, James J.; Horowitz, Jeffrey A.; Sullivan, David M.; Zhang, Qi; Sekiguchi, Fumiya; Woods, Gary L.; Hoffmann, Matthias C.; Nojiri, Hiroyuki; Takeda, Jun; Kono, Junichiro

    2016-12-01

    We have developed a single-shot terahertz time-domain spectrometer to perform optical-pump/terahertz-probe experiments in pulsed, high magnetic fields up to 30 T. The single-shot detection scheme for measuring a terahertz waveform incorporates a reflective echelon to create time-delayed beamlets across the intensity profile of the optical gate beam before it spatially and temporally overlaps with the terahertz radiation in a ZnTe detection crystal. After imaging the gate beam onto a camera, we can retrieve the terahertz time-domain waveform by analyzing the resulting image. To demonstrate the utility of our technique, we measured cyclotron resonance absorption of optically excited carriers in the terahertz frequency range in intrinsic silicon at high magnetic fields, with results that agree well with published values.

  2. Ultrafast single-shot imaging of laser-produced plasmas via spatial division and routing

    NASA Astrophysics Data System (ADS)

    Yeola, Sarang; Kuk, Donghoon; Kim, Ki-Yong

    2017-01-01

    We have developed a single-shot imaging camera, which can capture ultrafast events occurring on femtosecond and picosecond time scales. The working principle of this camera relies on spatial division and routing of femtosecond laser pulses. Here we have employed simple optics such as mirrors to produce multiple, time-delayed laser pulses and to project time-evolving images onto separate standard cameras. This spatial division and routing method has been tested with a femtosecond amplified laser in visualizing the evolution of laser-induced ionization in air and ablation in solids in single-shots. The number of frames is currently limited to 4 but can be increased further to N x N by using 3D printed optics for spatial division and routing. Work supported by the National Science Foundation (NSF) under Award No. 1351455.

  3. Single-shot digital holography by use of the fractional Talbot effect.

    PubMed

    Martínez-León, Lluís; Araiza-E, María; Javidi, Bahram; Andrés, Pedro; Climent, Vicent; Lancis, Jesús; Tajahuerce, Enrique

    2009-07-20

    We present a method for recording in-line single-shot digital holograms based on the fractional Talbot effect. In our system, an image sensor records the interference between the light field scattered by the object and a properly codified parallel reference beam. A simple binary two-dimensional periodic grating is used to codify the reference beam generating a periodic three-step phase distribution over the sensor plane by fractional Talbot effect. This provides a method to perform single-shot phase-shifting interferometry at frame rates only limited by the sensor capabilities. Our technique is well adapted for dynamic wavefront sensing applications. Images of the object are digitally reconstructed from the digital hologram. Both computer simulations and experimental results are presented.

  4. Single-shot dual-wavelength phase unwrapping in parallel phase-shifting digital holography.

    PubMed

    Lee, Yonghee; Ito, Yasunori; Tahara, Tatsuki; Inoue, Junichi; Xia, Peng; Awatsuji, Yasuhiro; Nishio, Kenzo; Ura, Shogo; Matoba, Osamu

    2014-04-15

    We propose a single-shot phase-unwrapping method using two wavelengths in parallel phase-shifting digital holography (PPSDH). The proposed method enables one to solve the phase ambiguity problem in PPSDH. We conducted an experiment of the proposed method using two lasers whose wavelengths are 473 and 532 nm. An object having about 1.9 μm step, which is 7.1 times larger than the half wavelength of one of the lasers (266 nm), was fabricated by using vapor deposition of aluminum. Single-shot measurement of the height of the object was successfully demonstrated, and the validity of the proposed method was verified.

  5. Computed tomography with single-shot dual-energy sandwich detectors

    NASA Astrophysics Data System (ADS)

    Kim, Seung Ho; Youn, Hanbean; Kim, Daecheon; Kim, Dong Woon; Jeon, Hosang; Kim, Ho Kyung

    2016-03-01

    Single-shot dual-energy sandwich detector can produce sharp images because of subtraction of images from two sub-detector layers, which have different thick x-ray converters, of the sandwich detector. Inspired by this observation, the authors have developed a microtomography system with the sandwich detector in pursuit of high-resolution bone-enhanced small-animal imaging. The preliminary results show that the bone-enhanced images reconstructed with the subtracted projection data are better in visibility of bone details than the conventionally reconstructed images. In addition, the bone-enhanced images obtained from the sandwich detector are relatively immune to the artifacts caused by photon starvation. The microtomography with the single-shot dual-energy sandwich detector will be useful for the high-resolution bone imaging.

  6. Frequency-domain single-shot optical frequency comb tomography using VIPA

    NASA Astrophysics Data System (ADS)

    Miyaoka, Takumi; Shioda, Tatsutoshi

    2016-03-01

    Novel two-dimensional single-shot imaging optical system based on Frequency-domain interferometry using a virtually imaged phased array is proposed. The VIPA simultaneously outputs incoherent optical frequency combs (OFCs) whose teeth interval are scanned as a function of its output angle. Teeth intervals of the OFCs only in a reference are spatially swept by using of a VIPA whose advantage compared to an optical resonator. Thus, the single-shot imaging system can be realized with the FSR scanned frequency-domain OFC interference monitored by CCD. This system enable high speed 2-dimensional tomographic image without mechanical moving part. And the axial measurement range is not limited by using multi-order interference that is generated by OFCs interferometry. We will present the operation principle with its confirmed results in terms of both simulation and experiment.

  7. Broadband pump-probe imaging spectroscopy applicable to ultrafast single-shot events

    NASA Astrophysics Data System (ADS)

    Minami, Yasuo; Yamaki, Hiromoto; Katayama, Ikufumi; Takeda, Jun

    2014-02-01

    We propose a scheme for frequency-resolved single-shot spectroscopy with an echelon mirror. The echelon mirror is employed to generate spatially encoded time delays for the white-light continuum probe beam; it produces a temporal step of 66 fs and an overall time delay of 33 ps. We demonstrate broadband pump-probe imaging spectroscopy and present time-frequency two-dimensional images of the transient absorption of β-carotene between 420 and 630 nm with single-shot detection. The results show that this technique is a powerful tool for observing the ultrafast, broadband transient dynamics of materials that exhibit irreversible reactions or deterioration by laser pulse irradiation.

  8. Single-shot electron bunch length measurements using a spatial electro-optical autocorrelation interferometer.

    PubMed

    Sütterlin, Daniel; Erni, Daniel; Schlott, Volker; Sigg, Hans; Jäckel, Heinz; Murk, Axel

    2010-10-01

    A spatial, electro-optical autocorrelation (EOA) interferometer using the vertically polarized lobes of coherent transition radiation (CTR) has been developed as a single-shot electron bunch length monitor at an optical beam port downstream the 100 MeV preinjector LINAC of the Swiss Light Source. This EOA monitor combines the advantages of step-scan interferometers (high temporal resolution) [D. Mihalcea et al., Phys. Rev. ST Accel. Beams 9, 082801 (2006) and T. Takahashi and K. Takami, Infrared Phys. Technol. 51, 363 (2008)] and terahertz-gating technologies [U. Schmidhammer et al., Appl. Phys. B: Lasers Opt. 94, 95 (2009) and B. Steffen et al., Phys. Rev. ST Accel. Beams 12, 032802 (2009)] (fast response), providing the possibility to tune the accelerator with an online bunch length diagnostics. While a proof of principle of the spatial interferometer was achieved by step-scan measurements with far-infrared detectors, the single-shot capability of the monitor has been demonstrated by electro-optical correlation of the spatial CTR interference pattern with fairly long (500 ps) neodymium-doped yttrium aluminum garnet (Nd:YAG) laser pulses in a ZnTe crystal. In single-shot operation, variations of the bunch length between 1.5 and 4 ps due to different phase settings of the LINAC bunching cavities have been measured with subpicosecond time resolution.

  9. Single-shot electron bunch length measurements using a spatial electro-optical autocorrelation interferometer

    NASA Astrophysics Data System (ADS)

    Sütterlin, Daniel; Erni, Daniel; Schlott, Volker; Sigg, Hans; Jäckel, Heinz; Murk, Axel

    2010-10-01

    A spatial, electro-optical autocorrelation (EOA) interferometer using the vertically polarized lobes of coherent transition radiation (CTR) has been developed as a single-shot electron bunch length monitor at an optical beam port downstream the 100 MeV preinjector LINAC of the Swiss Light Source. This EOA monitor combines the advantages of step-scan interferometers (high temporal resolution) [D. Mihalcea et al., Phys. Rev. ST Accel. Beams 9, 082801 (2006) and T. Takahashi and K. Takami, Infrared Phys. Technol. 51, 363 (2008)] and terahertz-gating technologies [U. Schmidhammer et al., Appl. Phys. B: Lasers Opt. 94, 95 (2009) and B. Steffen et al., Phys. Rev. ST Accel. Beams 12, 032802 (2009)] (fast response), providing the possibility to tune the accelerator with an online bunch length diagnostics. While a proof of principle of the spatial interferometer was achieved by step-scan measurements with far-infrared detectors, the single-shot capability of the monitor has been demonstrated by electro-optical correlation of the spatial CTR interference pattern with fairly long (500 ps) neodymium-doped yttrium aluminum garnet (Nd:YAG) laser pulses in a ZnTe crystal. In single-shot operation, variations of the bunch length between 1.5 and 4 ps due to different phase settings of the LINAC bunching cavities have been measured with subpicosecond time resolution.

  10. Broadband Single-Shot Electron Spectrometer for GeV-Class Laser Plasma Based Accelerators

    SciTech Connect

    Nakamura, K.; Wan, W.; Ybarrolaza, N.; Syversrud, D.; Wallig, J.; Leemans, W.P.

    2008-05-01

    Laser-plasma-based accelerators can provide electrons over a broad energy range and/or with large momentum spread. The electron beam energy distribution can be controlled via accurate control of laser and plasma properties, and beams with energies ranging from'0.5 to 1000 MeV have been observed. Measuring these energy distributions in a single shot requires the use of a diagnostic with large momentum acceptance and, ideally, sufficient resolution to accurately measure energy spread in the case of narrow energy spread. Such a broadband single-shot electron magnetic spectrometer for GeV-class laser-plasma-based accelerators has been developed at Lawrence Berkeley National Laboratory. A detailed description of the hardware and the design concept is presented, as well as a performance evaluation of the spectrometer. The spectrometer covered electron beam energies raging from 0.01 to 1.1 GeV in a single shot, and enabled the simultaneous measurement of the laser properties at the exit of the accelerator through the use of a sufficiently large pole gap. Based on measured field maps and 3rd-order transport analysis, a few percent-level resolution and determination of the absolute energy were achieved over the entire energy range. Laser-plasma-based accelerator experiments demonstrated the capability of the spectrometer as a diagnostic and its suitability for such a broadband electron source.

  11. Single-shot-capable fast multichannel Fourier transform interferometer based on a microfabricated 3D multimirror array

    NASA Astrophysics Data System (ADS)

    Moser, H. O.; Heussler, S. P.; Kalaiselvi, S. M. P.

    2012-06-01

    We present a Fourier transform interferometer that is capable to record single short pulses and fast continuous transient spectra. This is achieved by spatially parallel instead of time serial processing by means of a micro/nanomanufactured multimirror array and a pixellated detector camera. The multimirror array is produced in excellent optical quality from poly(methyl methacrylate) by means of deep X-ray gray level lithography including multiple moving masks followed by sputter deposition of the gold reflecting surfaces. The crucial components such as the multimirror array and the pixellated camera are part of a straightforward optical system similar to a Czerny-Turner mount. Results demonstrate single shot measurements down to 320 μs, only limited by the camera shutter and the infrared source, and the time evolution of the absorption spectrum of an evaporating acetone layer that shows spectral changes during the first few seconds. While the spectral range of the multichannel Fourier transform interferometer (MC FTIR) as reported extends from near to mid infrared, multimirror arrays can be produced for spectra from visible to far infrared. Thus, the potential performance depends mostly on availability of detectors. The minimum pulse duration is determined by that photon number in the pulse which yields a sufficient signal to noise ratio, whereas the maximum acquisition rate of continuous transients is given by the frame rate of the detector.

  12. Anti-botulism single-shot vaccine using chitosan for protein encapsulation by simple coacervation.

    PubMed

    Sari, Roger S; de Almeida, Anna Christina; Cangussu, Alex S R; Jorge, Edson V; Mozzer, Otto D; Santos, Hércules Otacílio; Quintilio, Wagner; Brandi, Igor Viana; Andrade, Viviane Aguiar; Miguel, Angelo Samir M; Sobrinho Santos, Eliane M

    2016-12-01

    The aim of the present study was to compare the potency and safety of vaccines against Clostridium botulinum (C. botulinum) type C and D formulated with chitosan as controlled release matrix and vaccines formulated in conventional manner using aluminum hydroxide. Parameters were established for the development of chitosan microspheres, using simple coacervation to standardize the use of this polymer in protein encapsulation for vaccine formulation. To formulate a single shot vaccine inactivated antigens of C. botulinum type C and D were used with original toxin titles equal to 5.2 and 6.2 log LD50/ml, respectively. For each antigen a chitosan based solution of 50 mL was prepared. Control vaccines were formulated by mixing toxoid type C and D with aluminum hydroxide [25% Al(OH)3, pH 6.3]. The toxoid sterility, innocuity and potency of vaccines were evaluated as stipulated by MAPA-BRASIL according to ministerial directive no. 23. Encapsulation efficiency of BSA in chitosan was 32.5-40.37%, while that the encapsulation efficiency to toxoid type C was 41,03% (1.94 mg/mL) and of the toxoid type D was 32.30% (1.82 mg/mL). The single shot vaccine formulated using chitosan for protein encapsulation through simple coacervation showed potency and safety similar to conventional vaccine currently used in Brazilian livestock (10 and 2 IU/mL against C. botulinum type C and D, respectively). The present work suggests that our single shot vaccine would be a good option as a cattle vaccine against these C. botulinum type C and D.

  13. Phase retrieval without unwrapping by single-shot dual-wavelength digital holography

    NASA Astrophysics Data System (ADS)

    Min, Junwei; Yao, Baoli; Zhou, Meiling; Guo, Rongli; Lei, Ming; Yang, Yanlong; Dan, Dan; Yan, Shaohui; Peng, Tong

    2014-12-01

    A phase retrieval method by using single-shot dual-wavelength digital holography is proposed. Each single wavelength hologram is extracted from the color CCD recorded hologram at one exposure, and the unwrapped phase image of object can be reconstructed directly. Different from the traditional multiple wavelength phase unwrapping techniques, any single complex wave-fronts at different wavelengths have no need to be calculated any more. Thus, the phase retrieval is computationally fast and straightforward, and the limitations on the total optical path difference are significantly relaxed. The practicability of the proposed method is demonstrated by both simulated and experimental results.

  14. Single-shot spatiotemporal measurements of high-field terahertz pulses

    SciTech Connect

    van Tilborg, Jeroen; Schroeder, Carl; Toth, Csaba; Geddes, Cameron; Esarey, Eric; Leemans, Wim

    2011-06-17

    The electric field profiles of broad-bandwidth coherent terahertz (THz) pulses, emitted by laser-wakefield-accelerated electron bunches, are studied. The near-single-cycle THz pulses are measured with two single-shot techniques in the temporal and spatial domains. Spectra of 0-6 THz and peak fields up to {approx_equal} 0.4 MV cm{sup -1} are observed. The measured field substructure demonstrates the manifestation of spatiotemporal coupling at focus, which affects the interpretation of THz radiation as a bunch diagnostic and in high-field pump-probe experiments.

  15. Single-shot femtosecond-pulsed phase-shifting digital holography.

    PubMed

    Kakue, Takashi; Itoh, Seiya; Xia, Peng; Tahara, Tatsuki; Awatsuji, Yasuhiro; Nishio, Kenzo; Ura, Shogo; Kubota, Toshihiro; Matoba, Osamu

    2012-08-27

    Parallel phase-shifting digital holography is capable of three-dimensional measurement of a dynamically moving object with a single-shot recording. In this letter, we demonstrated a parallel phase-shifting digital holography using a single femtosecond light pulse whose central wavelength and temporal duration were 800 nm and 96 fs, respectively. As an object, we set spark discharge in atmospheric pressure air induced by applying a high voltage to between two electrodes. The instantaneous change in phase caused by the spark discharge was clearly reconstructed. The reconstructed phase image shows the change of refractive index of air was -3.7 × 10(-4).

  16. A grazing incidence x-ray streak camera for ultrafast, single-shot measurements

    SciTech Connect

    Feng, Jun; Engelhorn, K.; Cho, B.I.; Lee, H.J.; Greaves, M.; Weber, C.P.; Falcone, R.W.; Padmore, H. A.; Heimann, P.A.

    2010-02-18

    An ultrafast x-ray streak camera has been realized using a grazing incidence reflection photocathode. X-rays are incident on a gold photocathode at a grazing angle of 20 degree and photoemitted electrons are focused by a large aperture magnetic solenoid lens. The streak camera has high quantum efficiency, 600fs temporal resolution, and 6mm imaging length in the spectral direction. Its single shot capability eliminates temporal smearing due to sweep jitter, and allows recording of the ultrafast dynamics of samples that undergo non-reversible changes.

  17. Cryogenic single-shot spectroscopy of a floating poly-silicon gate transistor

    NASA Astrophysics Data System (ADS)

    Tenorio-Pearl, J. O.; Milne, W. I.; Hasko, D. G.

    2012-07-01

    Trapped electrons, located close to the channel of a transistor, are promising as data storage elements in non-classical information processing. Cryogenic microwave spectroscopy has shown that these electrons give rise to high quality factor resonances in the drain current and a post excitation dynamic behaviour that is related to the system lifetime. Using a floating poly-silicon gate transistor, single shot spectroscopy is performed to characterise the dynamic behaviour during excitation. This behaviour is seen to be dominated by the decay of the transient component, which gives rise to oscillations around the high quality factor resonance.

  18. Delay interferometric single shot measurement of a petawatt-class laser longitudinal chromatism corrector.

    PubMed

    Rouyer, C; Blanchot, N; Neauport, J; Sauteret, C

    2007-03-05

    In this paper we present a self-referenced interferometric single-shot measurement technique that we use to evaluate the longitudinal chromatism compensation made by a diffractive lens corrector. A diffractive lens with a delay of 1 ps is qualified for a 60 mm beam aperture. This corrector was implemented on the Alisé Nd:glass power chain. We qualify the corrector and the Alisé power chain chromatism, demonstrating the potential of this measuring principle as well as the interest of diffractive lenses to correct longitudinal chromatism of petawatt-class lasers.

  19. Single-shot high-voltage circuit for electrical capacitance tomography

    NASA Astrophysics Data System (ADS)

    Smolik, W. T.; Kryszyn, J.; Radzik, B.; Stosio, M.; Wróblewski, P.; Wanta, D.; Dańko, Ł.; Olszewski, T.; Szabatin, R.

    2017-02-01

    A new method of capacitance measurement for electrical capacitance tomography is presented. A single-shot excitation is used to accelerate measurement. A high-voltage pulse and oversampling of received signal are applied to obtain an acceptable signal-to-noise ratio. The results of measurements of standard capacitors and mutual capacitance of electrodes in 16 electrode tomographic sensors are presented. The elaborated circuit is stray-immune. It can measure capacitance in a range from about 1 fF to 1 pF at one gain setting with good linearity and precision at the rate of 20 000 samples per second.

  20. Ultrahigh wavelength range (300nm-2μm) polarization-independent 500gs/s single-shot pulse, all-optical real time oscilloscope

    NASA Astrophysics Data System (ADS)

    Gleyze, Jean-François; Hocquet, Steve; Monnier Bourdin, Dominique; Le Boudec, Patrice; Arnaud, Romain; Chassagne, Bruno; Jolly, Alain; Penninckx, Denis

    2014-03-01

    The development of ultra-broadband oscilloscopes is mainly governed by the needs of future telecom networks. But other applications are requesting the availability of true real-time acquisition oscilloscopes. Systems able to be used in single-shot operation are of prime interest for Inertial Confinement Fusion (ICF) and for the related R&D for plasma physics. We previously demonstrate a single-shot, 100GHz design of an all-optical sampling oscilloscope at 1μm (MULO). This laboratory system has been improved in stability and compactness to make an all-in-one box prototype. More, by the addition of an opto-electro-optics (OEO) sub-system at the input, we developed the ability to use this oscilloscope to analyze an electrical input signal up to 60GHz. This new integrated subset also increases the range of wavelength for optical input signal, from 300nm up to 2μm. Furthermore, it allows the use of inexpensive opto-electronic components at telecom wavelength for this system regardless of the signal to be analysed. In parallel with these improvements, by optimizing the heart of the system, we get a very high sampling rate, up to 500Gs/s and more; this allows considering much higher bandwidths in the future. In this talk, we will present latest developments and integration of this system. It will also allow us to give more details on the innovative OEO sub-system.

  1. High-resolution DTI of a localized volume using 3D single-shot diffusion-weighted STimulated echo-planar imaging (3D ss-DWSTEPI).

    PubMed

    Jeong, Eun-Kee; Kim, Seong-Eun; Kholmovski, Eugene G; Parker, Dennis L

    2006-12-01

    Diffusion tensor MRI (DTI) using conventional single-shot (SS) 2D diffusion-weighted (DW)-EPI is subject to severe susceptibility artifacts. Multishot DW imaging (DWI) techniques can reduce these distortions, but they generally suffer from artifacts caused by motion-induced phase errors. Parallel imaging can also reduce the distortions if the sensitivity profiles of the receiver coils allow a sufficiently high reduction factor for the desired field of view (FOV). A novel 3D DTI technique, termed 3D single-shot STimulated EPI (3D ss-STEPI), was developed to acquire high-resolution DW images of a localized region. The new technique completes k-space acquisition of a limited 3D volume after a single diffusion preparation. Because the DW magnetization is stored in the longitudinal direction until readout, it undergoes T(1) rather than T(2) decay. Inner volume imaging (IVI) is used to limit the imaging volume. This reduces the time required for EPI readout of each complete k(x)-k(y) plane, and hence reduces T(2)(*) decay during the readout and T(1) decay between the readout of each k(z). 3D ss-STEPI images appear to be free of severe susceptibility and motion artifacts. 3D ss-STEPI allows high-resolution DTI of limited volumes of interest, such as localized brain regions, cervical spinal cord, optic nerve, and other extracranial organs.

  2. Dose verification of single shot gamma knife applications using VIPAR polymer gel and MRI

    NASA Astrophysics Data System (ADS)

    Karaiskos, P.; Petrokokkinos, L.; Tatsis, E.; Angelopoulos, A.; Baras, P.; Kozicki, M.; Papagiannis, P.; Rosiak, J. M.; Sakelliou, L.; Sandilos, P.; Vlachos, L.

    2005-03-01

    This work describes an experimental procedure with potential to assess the overall accuracy associated with gamma knife clinical applications, from patient imaging and dosimetry planning to patient positioning and dose delivery using the automated positioning system of a Leksell Gamma Knife model C. The VIPAR polymer gel-MRI dosimetry method is employed due to its inherent three-dimensional feature and linear dose response over the range of gamma knife applications. Different polymer gel vials were irradiated with single shot gamma knife treatment plans using each of the four available collimator helmets to deliver a maximum dose of 30 Gy. Percentage relative dose results are presented not only in the form of one-dimensional profiles but also planar isocontours and isosurfaces in three dimensions. Experimental results are compared with corresponding Gammaplan treatment planning system calculations as well as acceptance test radiochromic film measurements. A good agreement, within the experimental uncertainty, is observed between measured and expected dose distributions. This experimental uncertainty is of the order of one imaging pixel in the MRI gel readout session (<1 mm) and allows for the verification of single shot gamma knife applications in terms of acceptance specifications for precision in beam alignment and accuracy. Averaging net R2 results in the dose plateau of the 4 mm and 18 mm collimator irradiated gel vials, which were MR scanned in the same session, provides a crude estimate of the 4 mm output factor which agrees within errors with the default value of 0.870.

  3. Single-shot magnetic resonance spectroscopic imaging with partial parallel imaging.

    PubMed

    Posse, Stefan; Otazo, Ricardo; Tsai, Shang-Yueh; Yoshimoto, Akio Ernesto; Lin, Fa-Hsuan

    2009-03-01

    A magnetic resonance spectroscopic imaging (MRSI) pulse sequence based on proton-echo-planar-spectroscopic-imaging (PEPSI) is introduced that measures two-dimensional metabolite maps in a single excitation. Echo-planar spatial-spectral encoding was combined with interleaved phase encoding and parallel imaging using SENSE to reconstruct absorption mode spectra. The symmetrical k-space trajectory compensates phase errors due to convolution of spatial and spectral encoding. Single-shot MRSI at short TE was evaluated in phantoms and in vivo on a 3-T whole-body scanner equipped with a 12-channel array coil. Four-step interleaved phase encoding and fourfold SENSE acceleration were used to encode a 16 x 16 spatial matrix with a 390-Hz spectral width. Comparison with conventional PEPSI and PEPSI with fourfold SENSE acceleration demonstrated comparable sensitivity per unit time when taking into account g-factor-related noise increases and differences in sampling efficiency. LCModel fitting enabled quantification of inositol, choline, creatine, and N-acetyl-aspartate (NAA) in vivo with concentration values in the ranges measured with conventional PEPSI and SENSE-accelerated PEPSI. Cramer-Rao lower bounds were comparable to those obtained with conventional SENSE-accelerated PEPSI at the same voxel size and measurement time. This single-shot MRSI method is therefore suitable for applications that require high temporal resolution to monitor temporal dynamics or to reduce sensitivity to tissue movement.

  4. Direct single-shot phase retrieval from the diffraction pattern of separated objects

    PubMed Central

    Leshem, Ben; Xu, Rui; Dallal, Yehonatan; Miao, Jianwei; Nadler, Boaz; Oron, Dan; Dudovich, Nirit; Raz, Oren

    2016-01-01

    The non-crystallographic phase problem arises in numerous scientific and technological fields. An important application is coherent diffractive imaging. Recent advances in X-ray free-electron lasers allow capturing of the diffraction pattern from a single nanoparticle before it disintegrates, in so-called ‘diffraction before destruction' experiments. Presently, the phase is reconstructed by iterative algorithms, imposing a non-convex computational challenge, or by Fourier holography, requiring a well-characterized reference field. Here we present a convex scheme for single-shot phase retrieval for two (or more) sufficiently separated objects, demonstrated in two dimensions. In our approach, the objects serve as unknown references to one another, reducing the phase problem to a solvable set of linear equations. We establish our method numerically and experimentally in the optical domain and demonstrate a proof-of-principle single-shot coherent diffractive imaging using X-ray free-electron lasers pulses. Our scheme alleviates several limitations of current methods, offering a new pathway towards direct reconstruction of complex objects. PMID:26899582

  5. Direct single-shot phase retrieval from the diffraction pattern of separated objects

    SciTech Connect

    Leshem, Ben; Xu, Rui; Dallal, Yehonatan; Miao, Jianwei; Nadler, Boaz; Oron, Dan; Dudovich, Nirit; Raz, Oren

    2016-02-22

    The non-crystallographic phase problem arises in numerous scientific and technological fields. An important application is coherent diffractive imaging. Recent advances in X-ray free-electron lasers allow capturing of the diffraction pattern from a single nanoparticle before it disintegrates, in so-called ‘diffraction before destruction’ experiments. Presently, the phase is reconstructed by iterative algorithms, imposing a non-convex computational challenge, or by Fourier holography, requiring a well-characterized reference field. Here we present a convex scheme for single-shot phase retrieval for two (or more) sufficiently separated objects, demonstrated in two dimensions. In our approach, the objects serve as unknown references to one another, reducing the phase problem to a solvable set of linear equations. We establish our method numerically and experimentally in the optical domain and demonstrate a proof-of-principle single-shot coherent diffractive imaging using X-ray free-electron lasers pulses. Lastly, our scheme alleviates several limitations of current methods, offering a new pathway towards direct reconstruction of complex objects.

  6. Single-shot laser pulse reconstruction based on self-phase modulated spectra measurements

    PubMed Central

    Anashkina, Elena A.; Ginzburg, Vladislav N.; Kochetkov, Anton A.; Yakovlev, Ivan V.; Kim, Arkady V.; Khazanov, Efim A.

    2016-01-01

    We report a method for ultrashort pulse reconstruction based only on the pulse spectrum and two self-phase modulated (SPM) spectra measured after pulse propagation through thin media with a Kerr nonlinearity. The advantage of this method is that it is a simple and very effective tool for characterization of complex signals. We have developed a new retrieval algorithm that was verified by reconstructing numerically generated fields, such as a complex electric field of double pulses and few-cycle pulses with noises, pedestals and dips down to zero spectral intensity, which is challenging for commonly used techniques. We have also demonstrated a single-shot implementation of the technique for the reconstruction of experimentally obtained pulses. This method can be used for high power laser systems operating in a single-shot mode in the optical, near- and mid-IR spectral ranges. The method is robust, low cost, stable to noise, does not require a priori information, and has no ambiguity related to time direction. PMID:27646027

  7. Single-Shot Femtosecond X-ray Diffraction from Randomly Oriented Ellipsoidal Nanoparticles

    SciTech Connect

    Bogan, M.J.; Boutet, S.; Barty, A.; Benner, W.H.; Frank, M.; Lomb, L.; Shoeman, R.; Starodub, D.; Seibert, M.M.; Hau-Riege, S.P.; Woods, B.; Decorwin-Martin, P.; Bajt, S.; Schulz, J.; Rohner, U.; Iwan, B.; Timneanu, N.; Marchesini, S.; Schlichting, I.; Hajdu, J.; Chapman, H.N.; /DESY /Hamburg U., Inst. Theor. Phys. II

    2012-04-18

    Coherent diffractive imaging of single particles using the single-shot 'diffract and destroy' approach with an x-ray free electron laser (FEL) was recently demonstrated. A high-resolution low-noise coherent diffraction pattern, representative of the object before it turns into a plasma and explodes, results from the interaction of the FEL with the particle. Iterative phase retrieval algorithms are used to reconstruct two-dimensional projection images of the object from the recorded intensities alone. Here we describe the first single-shot diffraction data set that mimics the data proposed for obtaining 3D structure from identical particles. Ellipsoidal iron oxide nanoparticles (250 nm x 50 nm) were aerosolized and injected through an aerodynamic lens stack into a soft x-ray FEL. Particle orientation was not controlled with this injection method. We observed that, at the instant the x-ray pulse interacts with the particle, a snapshot of the particle's orientation is encoded in the diffraction pattern. The results give credence to one of the technical concepts of imaging individual nanometer and subnanometer-sized objects such as single molecules or larger clusters of molecules using hard x-ray FELs and will be used to help develop robust algorithms for determining particle orientations and 3D structure.

  8. A 7.5 ps single-shot precision integrated time counter with segmented delay line

    NASA Astrophysics Data System (ADS)

    Klepacki, K.; Szplet, R.; Pelka, R.

    2014-03-01

    This paper describes the design and test results of time interval counter featuring the single-shot precision of 7.5 ps root mean square (rms) and measurement range of 1 ms. These parameters have been achieved by combining direct counting method with a two-stage interpolation within a single clock period. Both stages of interpolation are based on the use of tapped delay lines stabilized by delay locked loop mechanism. In the first stage, a coarse resolution is obtained with the aid of high frequency multiphase clock, while in the second stage a sub-gate delay resolution is achieved with the use of differential delay line. To reduce the nonlinearities of conversion and to improve the precision of measurement, a novel segmented delay line is proposed. An important feature of this segmented delay line is partial overlapping of measurement range and resulting enhancement of both resolution and precision of time interval counter. The maximum integral nonlinearity error of the fine-stage interpolators does not exceed 16 ps and 14 ps in START and STOP interpolators, respectively. These errors have been identified by statistical calibration procedure and corrected to achieve single-shot precision better than 7.5 ps (rms). The time counter is integrated in a single ASIC (Application Specific Integrated Circuit) chip using a standard cost-effective 0.35 μm CMOS (Complementary Metal Oxide Semiconductor) process.

  9. A 7.5 ps single-shot precision integrated time counter with segmented delay line.

    PubMed

    Klepacki, K; Szplet, R; Pelka, R

    2014-03-01

    This paper describes the design and test results of time interval counter featuring the single-shot precision of 7.5 ps root mean square (rms) and measurement range of 1 ms. These parameters have been achieved by combining direct counting method with a two-stage interpolation within a single clock period. Both stages of interpolation are based on the use of tapped delay lines stabilized by delay locked loop mechanism. In the first stage, a coarse resolution is obtained with the aid of high frequency multiphase clock, while in the second stage a sub-gate delay resolution is achieved with the use of differential delay line. To reduce the nonlinearities of conversion and to improve the precision of measurement, a novel segmented delay line is proposed. An important feature of this segmented delay line is partial overlapping of measurement range and resulting enhancement of both resolution and precision of time interval counter. The maximum integral nonlinearity error of the fine-stage interpolators does not exceed 16 ps and 14 ps in START and STOP interpolators, respectively. These errors have been identified by statistical calibration procedure and corrected to achieve single-shot precision better than 7.5 ps (rms). The time counter is integrated in a single ASIC (Application Specific Integrated Circuit) chip using a standard cost-effective 0.35 μm CMOS (Complementary Metal Oxide Semiconductor) process.

  10. Direct single-shot phase retrieval from the diffraction pattern of separated objects

    DOE PAGES

    Leshem, Ben; Xu, Rui; Dallal, Yehonatan; ...

    2016-02-22

    The non-crystallographic phase problem arises in numerous scientific and technological fields. An important application is coherent diffractive imaging. Recent advances in X-ray free-electron lasers allow capturing of the diffraction pattern from a single nanoparticle before it disintegrates, in so-called ‘diffraction before destruction’ experiments. Presently, the phase is reconstructed by iterative algorithms, imposing a non-convex computational challenge, or by Fourier holography, requiring a well-characterized reference field. Here we present a convex scheme for single-shot phase retrieval for two (or more) sufficiently separated objects, demonstrated in two dimensions. In our approach, the objects serve as unknown references to one another, reducing themore » phase problem to a solvable set of linear equations. We establish our method numerically and experimentally in the optical domain and demonstrate a proof-of-principle single-shot coherent diffractive imaging using X-ray free-electron lasers pulses. Lastly, our scheme alleviates several limitations of current methods, offering a new pathway towards direct reconstruction of complex objects.« less

  11. The LCLS variable-energy hard X-ray single-shot spectrometer.

    PubMed

    Rich, David; Zhu, Diling; Turner, James; Zhang, Dehong; Hill, Bruce; Feng, Yiping

    2016-01-01

    The engineering design, implementation, operation and performance of the new variable-energy hard X-ray single-shot spectrometer (HXSSS) for the LCLS free-electron laser (FEL) are reported. The HXSSS system is based on a cylindrically bent Si thin crystal for dispersing the incident polychromatic FEL beam. A spatially resolved detector system consisting of a Ce:YAG X-ray scintillator screen, an optical imaging system and a low-noise pixelated optical camera is used to record the spectrograph. The HXSSS provides single-shot spectrum measurements for users whose experiments depend critically on the knowledge of the self-amplified spontaneous emission FEL spectrum. It also helps accelerator physicists for the continuing studies and optimization of self-seeding, various improved mechanisms for lasing mechanisms, and FEL performance improvements. The designed operating energy range of the HXSSS is from 4 to 20 keV, with the spectral range of order larger than 2% and a spectral resolution of 2 × 10(-5) or better. Those performance goals have all been achieved during the commissioning of the HXSSS.

  12. Single-shot laser pulse reconstruction based on self-phase modulated spectra measurements

    NASA Astrophysics Data System (ADS)

    Anashkina, Elena A.; Ginzburg, Vladislav N.; Kochetkov, Anton A.; Yakovlev, Ivan V.; Kim, Arkady V.; Khazanov, Efim A.

    2016-09-01

    We report a method for ultrashort pulse reconstruction based only on the pulse spectrum and two self-phase modulated (SPM) spectra measured after pulse propagation through thin media with a Kerr nonlinearity. The advantage of this method is that it is a simple and very effective tool for characterization of complex signals. We have developed a new retrieval algorithm that was verified by reconstructing numerically generated fields, such as a complex electric field of double pulses and few-cycle pulses with noises, pedestals and dips down to zero spectral intensity, which is challenging for commonly used techniques. We have also demonstrated a single-shot implementation of the technique for the reconstruction of experimentally obtained pulses. This method can be used for high power laser systems operating in a single-shot mode in the optical, near- and mid-IR spectral ranges. The method is robust, low cost, stable to noise, does not require a priori information, and has no ambiguity related to time direction.

  13. Single-shot carrier-envelope-phase-tagged ion-momentum imaging of nonsequential double ionization of argon in intense 4-fs laser fields

    SciTech Connect

    Johnson, Nora G.; Herrwerth, O.; Wirth, A.; De, S.; Ben-Itzhak, I.; Lezius, M.; Bergues, B.; Kling, M. F.; Senftleben, A.; Schroeter, C. D.; Moshammer, R.; Ullrich, J.; Betsch, K. J.; Jones, R. R.; Sayler, A. M.; Rathje, T.; Ruehle, K.; Mueller, W.; Paulus, G. G.

    2011-01-15

    Single-shot carrier-envelope-phase (CEP) tagging is combined with a reaction mircoscope (REMI) to investigate CEP-dependent processes in atoms. Excellent experimental stability and data acquisition longevity are achieved. Using this approach, we study the CEP effects for nonsequential double ionization of argon in 4-fs laser fields at 750 nm and an intensity of 1.6x10{sup 14} W/cm{sup 2}. The Ar{sup 2+} ionization yield shows a pronounced CEP dependence which compares well with recent theoretical predictions employing quantitative rescattering theory [S. Micheau et al., Phys. Rev. A 79, 013417 (2009)]. Furthermore, we find strong CEP influences on the Ar{sup 2+} momentum spectra along the laser polarization axis.

  14. Single-shot selective laser micromachining of filtered arc deposited TiN films from chromium underlayer

    NASA Astrophysics Data System (ADS)

    Dowling, Andrew J.; Ghantasala, Muralidhar K.; Evans, Peter E.; Hayes, Jason P.; Harvey, Erol C.; Doyle, E. Derry

    2002-11-01

    This paper presents the results on single-shot laser micromachining of filtered arc deposited TiN films and compares the machining characteristics of the films deposited under partially and fully filtered conditions. Machining performance was evaluated in terms of patterning quality and the ability to perform selective removal of top TiN film with minimal interference to an underlying layer. TiN was arc-deposited onto silicon substrate with a chromium layer on the top. These films were analysed for their composition and microstructure using Rutherford Backscattering Spectroscopy (RBS) and Scanning Electron Microscopy (SEM) before and after laser machining. Under single shot conditions the effect of fluence on the machined features has been investigated. The results showed selective removal of TiN films with a single shot from the underlying Cr layer. Further, this work clearly shows a distinction between the laser machining characteristics of the films deposited under different filtering conditions and substrate temperatures.

  15. Single-shot measurement of the complete temporal intensity and phase of supercontinuum

    NASA Astrophysics Data System (ADS)

    Wong, Tsz Chun; Rhodes, Michelle; Trebino, Rick

    2016-03-01

    We solve the problem of single-shot complete temporal measurement of continuum using cross-correlation frequency-resolved optical gating, achieving the necessary large spectral range using a polarization-gating geometry and the necessary large temporal range by significantly tilting the reference pulse. In addition, we simultaneously cancel the previously unavoidable longitudinal geometrical temporal smearing by using a carefully chosen combination of pulse tilt and beam-crossing angle, thus simultaneously achieving the required temporal resolution. The result is that we are able to make a complete measurement of an individual complex continuum pulse generated in photonic-crystal fiber. By enabling measurement of single optical rogue waves, this technique could provide insight and perhaps even lead to the prediction of when mathematically similar, destructive, oceanic rogue waves may occur.

  16. Single-shot incoherent digital holography using a dual-focusing lens with diffraction gratings.

    PubMed

    Quan, Xiangyu; Matoba, Osamu; Awatsuji, Yasuhiro

    2017-02-01

    A new optical configuration of incoherent digital holography is presented to improve the quality of reconstructed images when the random polarization state of incoherent light is used. The proposed system improves the signal-to-noise ratio of the holograms by suppressing the unmodulated terms of a spatial light modulator. To generate the self-interference of a quasi-incoherent point-like source, we use a dual-focusing lens with diffraction gratings. The preliminary experimental results confirm the validity of the proposed method by reconstructing two point-like sources generated by a LED light source. When the pixel pitch of the phase-mode SLM is small enough, the off-axis hologram can be generated. The single-shot recording of the incoherent digital holography is expected.

  17. Single-shot digital holography for fast measuring optical properties of fibers.

    PubMed

    Agour, Mostafa; El-Farahaty, Keremal; Seisa, Eman; Omar, Emam; Sokkar, Taha

    2015-10-01

    We propose a fast method for measuring optical properties, e.g., the refractive index profile and birefringence, of fibers. It is based on recovering the phase distribution of light refracted by a fiber sample at the recording plane from a single-shot digital hologram. During the recovering process, an optimized approach based on the spatial carrier frequency method was utilized. The proposed approach enhances affects that arise from the limited spatial extent of the bandpass filter associated with the implementation of the spatial carrier frequency method. In contrast to the low spatial resolution of off-axis digital holograms, the method ensures the best utilization of the camera support. From the recovered phase information, the optical path difference is measured; thus, the refractive index profile, the mean refractive index, and the birefringence of isotactic polypropylene (IPP) are determined. Experimental results are given for illustration.

  18. Axially distributed sensing with a monoscopic imaging lens for single-shot distance measurements.

    PubMed

    Sandner, Marc; Kolenović, Ervin; Klattenhoff, Reiner; Kolenović, Elam; Elandaloussi, Frank; von Kopylow, Christoph; Bergmann, Ralf B

    2014-08-01

    Using the image-based optical measurement method known as axially distributed sensing (ADS), the depth information of a scene is retrieved by evaluating images recorded with a camera positioned on multiple points along a common optical axis. We describe the design of a monoscopic lens that images the scene from two different on-axis points of perspective simultaneously onto a single camera. Designed for use in a territorial surveillance video system, this lens allows for capturing 3D scene information based on ADS with a single shot. We present the physical foundations of this approach and its implementation as a compact lens system and show the usability of the system prototype, supported by performance tests.

  19. Single-shot measurements of plasmons in compressed diamond with an x-ray lasera)

    NASA Astrophysics Data System (ADS)

    Gamboa, E. J.; Fletcher, L. B.; Lee, H. J.; Zastrau, U.; Galtier, E.; MacDonald, M. J.; Gauthier, M.; Vorberger, J.; Gericke, D. O.; Granados, E.; Hastings, J. B.; Glenzer, S. H.

    2015-05-01

    Strong plasmon resonances characteristics of electron density fluctuations have recently been observed in dynamically compressed diamond for the first time at the Linac Coherent Light Source. These experiments observe the forward scattering spectra from 8 keV x-ray pulses at record peak brightness to probe laser-compressed diamond foils at the Matter in Extreme Conditions instrument. We demonstrate single-shot measurements of the x-ray scattering spectrum, which are sensitive to the temperatures and densities of the compressed samples. The inferred values from the inelastic scattering are compared to simulations, finding good agreement with the temperature and demonstrating the need to include solid state effects in the modeling of the plasmon oscillation.

  20. Compressive sensing sectional imaging for single-shot in-line self-interference incoherent holography

    NASA Astrophysics Data System (ADS)

    Weng, Jiawen; Clark, David C.; Kim, Myung K.

    2016-05-01

    A numerical reconstruction method based on compressive sensing (CS) for self-interference incoherent digital holography (SIDH) is proposed to achieve sectional imaging by single-shot in-line self-interference incoherent hologram. The sensing operator is built up based on the physical mechanism of SIDH according to CS theory, and a recovery algorithm is employed for image restoration. Numerical simulation and experimental studies employing LEDs as discrete point-sources and resolution targets as extended sources are performed to demonstrate the feasibility and validity of the method. The intensity distribution and the axial resolution along the propagation direction of SIDH by angular spectrum method (ASM) and by CS are discussed. The analysis result shows that compared to ASM the reconstruction by CS can improve the axial resolution of SIDH, and achieve sectional imaging. The proposed method may be useful to 3D analysis of dynamic systems.

  1. Single-shot quantitative phase microscopy with color-multiplexed differential phase contrast (cDPC)

    PubMed Central

    2017-01-01

    We present a new technique for quantitative phase and amplitude microscopy from a single color image with coded illumination. Our system consists of a commercial brightfield microscope with one hardware modification—an inexpensive 3D printed condenser insert. The method, color-multiplexed Differential Phase Contrast (cDPC), is a single-shot variant of Differential Phase Contrast (DPC), which recovers the phase of a sample from images with asymmetric illumination. We employ partially coherent illumination to achieve resolution corresponding to 2× the objective NA. Quantitative phase can then be used to synthesize DIC and phase contrast images or extract shape and density. We demonstrate amplitude and phase recovery at camera-limited frame rates (50 fps) for various in vitro cell samples and c. elegans in a micro-fluidic channel. PMID:28152023

  2. Single-shot measurements of plasmons in compressed diamond with an x-ray laser

    SciTech Connect

    Gamboa, E. J.; Fletcher, L. B.; Lee, H. J.; Galtier, E.; Gauthier, M.; Granados, E.; Hastings, J. B.; Glenzer, S. H.; Zastrau, U.; MacDonald, M. J.; Vorberger, J.; Gericke, D. O.

    2015-05-15

    Strong plasmon resonances characteristics of electron density fluctuations have recently been observed in dynamically compressed diamond for the first time at the Linac Coherent Light Source. These experiments observe the forward scattering spectra from 8 keV x-ray pulses at record peak brightness to probe laser-compressed diamond foils at the Matter in Extreme Conditions instrument. We demonstrate single-shot measurements of the x-ray scattering spectrum, which are sensitive to the temperatures and densities of the compressed samples. The inferred values from the inelastic scattering are compared to simulations, finding good agreement with the temperature and demonstrating the need to include solid state effects in the modeling of the plasmon oscillation.

  3. Single-shot electro-optic sampling of coherent transition radiation at the A0 Photoinjector

    SciTech Connect

    Maxwell, T.J.; Ruan, J.; Piot, P.; Thurman-Keup, R.; /Fermilab

    2011-08-01

    Future collider applications and present high-gradient laser plasma wakefield accelerators operating with picosecond bunch durations place a higher demand on the time resolution of bunch distribution diagnostics. This demand has led to significant advancements in the field of electro-optic sampling over the past ten years. These methods allow the probing of diagnostic light such as coherent transition radiation or the bunch wakefields with sub-picosecond time resolution. Potential applications in shot-to-shot, non-interceptive diagnostics continue to be pursued for live beam monitoring of collider and pump-probe experiments. Related to our developing work with electro-optic imaging, we present results on single-shot electro-optic sampling of the coherent transition radiation from bunches generated at the A0 photoinjector.

  4. Single-Shot Spectrally Resolved UV Rayleigh Scattering Measurements in High Speed Flow

    NASA Technical Reports Server (NTRS)

    Seasholtz, Richard G.

    1996-01-01

    A single-shot UV molecular Rayleigh scattering technique to measure velocity in high speed flow is described. The beam from an injection-seeded, frequency quadrupled Nd:YAG laser (266 nm) is focused to a line in a free air jet with velocities up to Mach 1.3. Rayleigh scattered light is imaged through a planar mirror Fabry-Perot interferometer onto a Charged Coupled Device (CCD) array detector. Some laser light is also simultaneously imaged through the Fabry-Perot to provide a frequency reference. Two velocity measurements are obtained from each image. Multiple-pulse data are also given. The Rayleigh scattering velocity data show good agreement with velocities calculated from isentropic flow relations.

  5. Development of a single-shot-imaging thin film for an online Thomson parabola spectrometer

    SciTech Connect

    Sakaki, H.; Fukuda, Y.; Nishiuchi, M.; Hori, T.; Yogo, A.; Jinno, S.; Kanasaki, M.; Niita, K.

    2013-01-15

    A single-shot-imaging thin scintillator film was developed for an online Thomson parabola (TP) spectrometer and the first analysis of laser accelerated ions, using the online TP spectrometer, was demonstrated at the JAEA-Kansai Advanced Relativistic Engineering Laser System (J-KAREN). An energy spectrum of {approx}4.0 MeV protons is obtained using only this imaging film without the need of a microchannel plate that is typically utilized in online ion analyses. A general-purpose Monte Carlo particle and heavy ion-transport code system, which consists of various quantum dynamics models, was used for the prediction of the luminescent properties of the scintillator. The simulation can reasonably predict not only the ion trajectories detected by the spectrometer, but also luminescence properties.

  6. Single-shot spatially modulated Stokes polarimeter based on a GRIN lens.

    PubMed

    Chang, Jintao; Zeng, Nan; He, Honghui; He, Yonghong; Ma, Hui

    2014-05-01

    A new polarimeter for the simultaneous measurement of all Stokes parameters in a single shot is presented. It consists of only a gradient index (GRIN) lens, a polarizer, an imaging lens, and a CCD, without mechanical movements, electrical signal modulation, or the division of amplitude components. This design takes advantage of the continuous spatial distributions of birefringence value and the fast axis direction of a GRIN lens and derives the state of polarization (SOP) of the incident beam from the characteristic patterns on the CCD images. Tests show that this polarimeter is very accurate even with low-resolution images. It is versatile and adapts to light sources of different wavelengths. It is also very stable, robust, low cost, and simple to use.

  7. OPTIMIZATION AND SINGLE-SHOT CHARACTERIZATION OF ULTRASHORT THz PULSES FROM A LASER WAKEFIELD ACCELERATOR

    SciTech Connect

    Plateau, G. R.; Matlis, N. H.; van Tilborg, J.; Geddes, C. G. R.; Toth, Cs.; Schroeder, C. B.; Leemans, W. P.

    2009-05-04

    We present spatiotemporal characterization of J-class ultrashort THz pulses generated from a laser wakefield accelerator (LWFA). Accelerated electrons, resulting from the interaction of a high-intensity laser pulse with a plasma, emit high-intensity THz pulses as coherent transition radiation. Such high peak-power THz pulses, suitable for high-field (MV/cm) pump-probe experiments, also provide a non-invasive bunch-length diagnostic and thus feedback for the accelerator. The characterization of the THz pulses includes energy measurement using a Golay cell, 2D sign-resolved electro-optic measurement and single-shot spatiotemporal electric-field distribution retrieval using a new technique, coined temporal electric-field cross-Correlation (TEX). All three techniques corroborate THz pulses of 5 muJ, with peak fields of 100's of kV/cm and ~;;0:4 ps rms duration.

  8. Single-shot Readout of a Superconducting Qubit using a Josephson Parametric Oscillator

    NASA Astrophysics Data System (ADS)

    Krantz, Philip; Bengtsson, Andreas; Simoen, Michael; Gustavsson, Simon; Shumeiko, Vitaly; Oliver, W. D.; Wilson, C. M.; Delsing, Per; Bylander, Jonas

    We propose and demonstrate a new read-out technique for a superconducting qubit by dispersively coupling it to a Josephson parametric oscillator. We employ a tunable quarter-wavelength superconducting resonator and modulate its resonant frequency at twice its value with an amplitude surpassing the threshold for parametric instability. We map the qubit states onto two distinct states of classical parametric oscillation: one oscillating state, with 185 +/- ∑ 15 photons in the resonator, and one with zero oscillation amplitude. This high contrast obviates a following quantum-limited amplifier. We demonstrate proof-of-principle, single-shot readout performance, and present an error budget indicating that this method can surpass the fidelity threshold required for quantum computing. Support came from the Wallenberg foundation, the European Research Council (ERC), the Royal Swedish Academy of Science (KVA), the European project ScaleQIT, STINT, and Marie Curie CIG.

  9. Single-shot stand-off chemical identification of powders using random Raman lasing

    PubMed Central

    Hokr, Brett H.; Bixler, Joel N.; Noojin, Gary D.; Thomas, Robert J.; Rockwell, Benjamin A.; Yakovlev, Vladislav V.; Scully, Marlan O.

    2014-01-01

    The task of identifying explosives, hazardous chemicals, and biological materials from a safe distance is the subject we consider. Much of the prior work on stand-off spectroscopy using light has been devoted to generating a backward-propagating beam of light that can be used drive further spectroscopic processes. The discovery of random lasing and, more recently, random Raman lasing provide a mechanism for remotely generating copious amounts of chemically specific Raman scattered light. The bright nature of random Raman lasing renders directionality unnecessary, allowing for the detection and identification of chemicals from large distances in real time. In this article, the single-shot remote identification of chemicals at kilometer-scale distances is experimentally demonstrated using random Raman lasing. PMID:25114231

  10. Miniaturized Single-Shot Valve and its Application to the ExoMars Pasteur Payload

    NASA Technical Reports Server (NTRS)

    Muller, Pierre; Henkel, Hartmut; Klinkner, Sabine

    2010-01-01

    Hermetically sealing a gas tank and opening it into tubing under telecommand control is a function required in various space instruments. There are a number of space valves that are power saving, withstand vibration, and do not contaminate the gas. But none of them combines these features with low mass and the ability to withstand temperatures of 130 C during the sterilization process mandatory for planetary missions. In this paper, a novel miniature valve is presented, which is particularly adapted to space applications. It is electrically actuated, utilizing a bimetallic snap-disc that pierces a metallic membrane by a needle pin, thereby opening the valve. The design of this single-shot valve is such that it allows it to withstand a temperature of 130 C and a pressure of 50 bars. The valve is also lightweight (6.62 g) and it requires only 9 W to operate.

  11. Single-shot spatiotemporal measurements of ultrashort THz waveforms using temporal electric-field cross correlation

    SciTech Connect

    Matlis, Nicholas; Plateau, Guillaume; van Tilborg, Jeroen; Leemans, Wim

    2011-06-17

    A new single-shot technique based on linear spectral interferometry between a temporally short reader pulse and a temporally long probe pulse is demonstrated for measuring the spatiotemporal phase and amplitude of an optical probe for use as an ultrafast diagnostic. The probe spatiotemporal field information is recovered, with a resolution set by the duration of the reader pulse, by applying a single Fourier transform operation to the interferogram image, without need of any reference data. The technique was used in conjunction with electro-optic sampling to measure waveforms of coherent, ultrashort THz pulses emitted by electron bunches from a laser-plasma accelerator with sub-50fs resolution. The presence of strong spatiotemporal coupling in the THz waveforms and of complex temporal electron-bunch structure was determined.

  12. Sequential Single Shot X-ray Photon Correlation Spectroscopy at the SACLA Free Electron Laser

    PubMed Central

    Lehmkühler, Felix; Kwaśniewski, Paweł; Roseker, Wojciech; Fischer, Birgit; Schroer, Martin A.; Tono, Kensuke; Katayama, Tetsuo; Sprung, Michael; Sikorski, Marcin; Song, Sanghoon; Glownia, James; Chollet, Matthieu; Nelson, Silke; Robert, Aymeric; Gutt, Christian; Yabashi, Makina; Ishikawa, Tetsuya; Grübel, Gerhard

    2015-01-01

    Hard X-ray free electron lasers allow for the first time to access dynamics of condensed matter samples ranging from femtoseconds to several hundred seconds. In particular, the exceptional large transverse coherence of the X-ray pulses and the high time-averaged flux promises to reach time and length scales that have not been accessible up to now with storage ring based sources. However, due to the fluctuations originating from the stochastic nature of the self-amplified spontaneous emission (SASE) process the application of well established techniques such as X-ray photon correlation spectroscopy (XPCS) is challenging. Here we demonstrate a single-shot based sequential XPCS study on a colloidal suspension with a relaxation time comparable to the SACLA free-electron laser pulse repetition rate. High quality correlation functions could be extracted without any indications for sample damage. This opens the way for systematic sequential XPCS experiments at FEL sources. PMID:26610328

  13. Single-shot quantitative phase microscopy with color-multiplexed differential phase contrast (cDPC).

    PubMed

    Phillips, Zachary F; Chen, Michael; Waller, Laura

    2017-01-01

    We present a new technique for quantitative phase and amplitude microscopy from a single color image with coded illumination. Our system consists of a commercial brightfield microscope with one hardware modification-an inexpensive 3D printed condenser insert. The method, color-multiplexed Differential Phase Contrast (cDPC), is a single-shot variant of Differential Phase Contrast (DPC), which recovers the phase of a sample from images with asymmetric illumination. We employ partially coherent illumination to achieve resolution corresponding to 2× the objective NA. Quantitative phase can then be used to synthesize DIC and phase contrast images or extract shape and density. We demonstrate amplitude and phase recovery at camera-limited frame rates (50 fps) for various in vitro cell samples and c. elegans in a micro-fluidic channel.

  14. Single-shot lamina thoracic paravertebral block with ketofol for modified radical mastectomy

    PubMed Central

    Rukewe, Ambrose; Afuwape, Oludolapo O; Ugheoke, Austin; Fatiregun, Akinola A

    2016-01-01

    We describe the use of single-shot lamina thoracic paravertebral block (TPVB) with sedation for a 56-year-old female patient who had modified radical mastectomy with axillary clearance. Two years ago, she suffered vocal cord palsy post thyroidectomy, which was managed with tracheostomy. The tracheostomy tube was removed 8 months later, leaving the patient with persistent hoarseness of voice and left vocal cord palsy. She declined general anesthesia and consented for TPVB. The surgery lasted 95 minutes and was successfully completed with TPVB. Her vital signs were stable during the operation. She had low pain scores, minimal opioid use, early alimentation, and no postoperative nausea and vomiting and was discharged early. We present the anesthetic management of this case in our setting, where TPVB under ultrasound guidance and modern drug-delivery systems for sedation are unavailable. PMID:27785098

  15. Single-shot read-out of a superconducting qubit using a Josephson parametric oscillator

    NASA Astrophysics Data System (ADS)

    Krantz, Philip; Bengtsson, Andreas; Simoen, Michaël; Gustavsson, Simon; Shumeiko, Vitaly; Oliver, W. D.; Wilson, C. M.; Delsing, Per; Bylander, Jonas

    2016-05-01

    We propose and demonstrate a read-out technique for a superconducting qubit by dispersively coupling it with a Josephson parametric oscillator. We employ a tunable quarter wavelength superconducting resonator and modulate its resonant frequency at twice its value with an amplitude surpassing the threshold for parametric instability. We map the qubit states onto two distinct states of classical parametric oscillation: one oscillating state, with 185+/-15 photons in the resonator, and one with zero oscillation amplitude. This high contrast obviates a following quantum-limited amplifier. We demonstrate proof-of-principle, single-shot read-out performance, and present an error budget indicating that this method can surpass the fidelity threshold required for quantum computing.

  16. Single-shot read-out of a superconducting qubit using a Josephson parametric oscillator

    PubMed Central

    Krantz, Philip; Bengtsson, Andreas; Simoen, Michaël; Gustavsson, Simon; Shumeiko, Vitaly; Oliver, W. D.; Wilson, C. M.; Delsing, Per; Bylander, Jonas

    2016-01-01

    We propose and demonstrate a read-out technique for a superconducting qubit by dispersively coupling it with a Josephson parametric oscillator. We employ a tunable quarter wavelength superconducting resonator and modulate its resonant frequency at twice its value with an amplitude surpassing the threshold for parametric instability. We map the qubit states onto two distinct states of classical parametric oscillation: one oscillating state, with 185±15 photons in the resonator, and one with zero oscillation amplitude. This high contrast obviates a following quantum-limited amplifier. We demonstrate proof-of-principle, single-shot read-out performance, and present an error budget indicating that this method can surpass the fidelity threshold required for quantum computing. PMID:27156732

  17. Sequential single shot X-ray photon correlation spectroscopy at the SACLA free electron laser

    SciTech Connect

    Lehmkühler, Felix; Kwaśniewski, Paweł; Roseker, Wojciech; Fischer, Birgit; Schroer, Martin A.; Tono, Kensuke; Katayama, Tetsuo; Sprung, Michael; Sikorski, Marcin; Song, Sanghoon; Glownia, James; Chollet, Matthieu; Nelson, Silke; Robert, Aymeric; Gutt, Christian; Yabashi, Makina; Ishikawa, Tetsuya; Grübel, Gerhard

    2015-11-27

    In this study, hard X-ray free electron lasers allow for the first time to access dynamics of condensed matter samples ranging from femtoseconds to several hundred seconds. In particular, the exceptional large transverse coherence of the X-ray pulses and the high time-averaged flux promises to reach time and length scales that have not been accessible up to now with storage ring based sources. However, due to the fluctuations originating from the stochastic nature of the self-amplified spontaneous emission (SASE) process the application of well established techniques such as X-ray photon correlation spectroscopy (XPCS) is challenging. Here we demonstrate a single-shot based sequential XPCS study on a colloidal suspension with a relaxation time comparable to the SACLA free-electron laser pulse repetition rate. High quality correlation functions could be extracted without any indications for sample damage. This opens the way for systematic sequential XPCS experiments at FEL sources.

  18. Ultrafast measurements of optical spectral coherence by single-shot time-stretch interferometry

    PubMed Central

    Xu, Yiqing; Wei, Xiaoming; Ren, Zhibo; Wong, Kenneth K. Y.; Tsia, Kevin K.

    2016-01-01

    The palette of laser technology has significantly been enriched by the innovations in ultrafast optical pulse generation. Our knowledge of the complex pulse dynamics, which is often highly nonlinear and stochastic in nature, is however limited by the scarcity of technologies that can measure fast variation/fluctuation of the spectral phase (or coherence) and amplitude in real-time, continuously. To achieve this goal, we demonstrate ultrafast interferometry enabled by optical time-stretch for real- time spectral coherence characterization with microsecond-resolution. Accessing the single-shot interferograms continuously, it further reveals the degree of second-order coherence, defined by the cross-spectral density function, at high speed-a capability absent in any existing spectroscopic measurement tools. As the technique can simultaneously measure both the high-speed variations of spectrally resolved coherence and intensity, time-stretch interferometry could create a new arena for ultrafast pulse characterization, especially favorable for probing and understanding the non-repetitive or stochastic dynamics in real-time. PMID:27295560

  19. One-dimensional single-shot thermometry in flames using femtosecond-CARS line imaging.

    PubMed

    Kulatilaka, W D; Stauffer, H U; Gord, J R; Roy, S

    2011-11-01

    We report single-laser-shot one-dimensional thermometry in flames using femtosecond coherent anti-Stokes Raman scattering (fs-CARS) line imaging. Fs-CARS enables high-repetition-rate (1-10 kHz), nearly collision-free measurement of temperature and species concentration in reacting flows. Two high-power 800 nm beams are used as the pump and probe beams and a 983 nm beam is used as the Stokes beam for CARS signal generation from the N2Q-branch transitions at ∼2330 cm(-1). The probe beam is frequency-chirped for single-laser-shot imaging. All three laser beams are formed into sheets and crossed in a line which forms the probe region. The resulting 1D line-CARS signal at ∼675 nm is spatially and spectrally resolved and recorded as a two-dimensional (2D) image. Single-shot temperature measurements are demonstrated in flat-field flames up to temperatures exceeding 2000 K, demonstrating the potential of fs-CARS line imaging for high-repetition-rate thermometry in turbulent flames. Such measurements can provide valuable data to validate complex turbulent-combustion models as well as increase the understanding of the spatio-temporal instabilities in practical combustion devices such as modern gas-turbine combustors and augmentors.

  20. Single-shot gas-phase thermometry by time-to-frequency mapping of coherence dephasing.

    PubMed

    Yue, Orin; Bremer, Marshall T; Pestov, Dmitry; Gord, James R; Roy, Sukesh; Dantus, Marcos

    2012-08-09

    We demonstrate a single-beam coherent anti-Stokes Raman scattering (CARS) technique for gas-phase thermometry that assesses the species-specific local gas temperature by single-shot time-to-frequency mapping of Raman-coherence dephasing. The proof-of-principle experiments are performed with air in a temperature-controlled gas cell. Impulsive excitation of molecular vibrations by an ultrashort pump/Stokes pulse is followed by multipulse probing of the 2330 cm(-1) Raman transition of N(2). This sequence of colored probe pulses, delayed in time with respect to each other and corresponding to three isolated spectral bands, imprints the coherence dephasing onto the measured CARS spectrum. For calibration purposes, the dephasing rates are recorded at various gas temperatures, and the relationship is fitted to a linear regression. The calibration data are then used to determine the gas temperature and are shown to provide better than 15 K accuracy. The described approach is insensitive to pulse energy fluctuations and can, in principle, gauge the temperature of multiple chemical species in a single laser shot, which is deemed particularly valuable for temperature profiling of reacting flows in gas-turbine combustors.

  1. Developing a Single-shot Polarimeter for Astronomy with Stessed-engineered Optics

    NASA Astrophysics Data System (ADS)

    Wolfe, Tristan; Stencel, Robert E.

    2017-01-01

    True single-shot polarimetry can be accomplished by utilizing a stress-engineered optic, with birefringence that varies spatially along its cross-section (Ramkhalawon et al. 2012). As light passes through such an optic, it will acquire a PSF that is unique to its polarization, providing the ability to measure all four Stokes parameters in a single image. This technique has not yet been adapted to astronomy. Our effort to do so faces several challenges, including the measurability of these PSFs for low polarizations, and through atmospheric turbulence. Current research demonstrates that low polarizations can remain measurable with the correct selection of stressed-optic and CCD parameters. Additionally, if signal is adequate (10^7 photons), then we demonstrate that turbulence does not negatively impact measurability. These results are leading toward the University of Denver's development of the first polarimeter to utilize these techniques in astronomy. This instrument will have intended applications of studying exoplanets and contributing to polarimetry surveys. The authors are grateful to the estate of William Herschel Womble for the support of astronomy at the University of Denver.

  2. Improved crystal orientation and physical properties from single-shot XFEL stills

    SciTech Connect

    Sauter, Nicholas K.; Hattne, Johan; Brewster, Aaron S.; Echols, Nathaniel; Zwart, Petrus H.; Adams, Paul D.

    2014-11-28

    X-ray diffraction patterns from still crystals are inherently difficult to process because the crystal orientation is not uniquely determined by measuring the Bragg spot positions. Only one of the three rotational degrees of freedom is directly coupled to spot positions; the other two rotations move Bragg spots in and out of the reflecting condition but do not change the direction of the diffracted rays. This hinders the ability to recover accurate structure factors from experiments that are dependent on single-shot exposures, such as femtosecond diffract-and-destroy protocols at X-ray free-electron lasers (XFELs). Here, additional methods are introduced to optimally model the diffraction. The best orientation is obtained by requiring, for the brightest observed spots, that each reciprocal-lattice point be placed into the exact reflecting condition implied by Bragg's law with a minimal rotation. This approach reduces the experimental uncertainties in noisy XFEL data, improving the crystallographic R factors and sharpening anomalous differences that are near the level of the noise.

  3. Improved crystal orientation and physical properties from single-shot XFEL stills

    DOE PAGES

    Sauter, Nicholas K.; Hattne, Johan; Brewster, Aaron S.; ...

    2014-11-28

    X-ray diffraction patterns from still crystals are inherently difficult to process because the crystal orientation is not uniquely determined by measuring the Bragg spot positions. Only one of the three rotational degrees of freedom is directly coupled to spot positions; the other two rotations move Bragg spots in and out of the reflecting condition but do not change the direction of the diffracted rays. This hinders the ability to recover accurate structure factors from experiments that are dependent on single-shot exposures, such as femtosecond diffract-and-destroy protocols at X-ray free-electron lasers (XFELs). Here, additional methods are introduced to optimally model themore » diffraction. The best orientation is obtained by requiring, for the brightest observed spots, that each reciprocal-lattice point be placed into the exact reflecting condition implied by Bragg's law with a minimal rotation. This approach reduces the experimental uncertainties in noisy XFEL data, improving the crystallographic R factors and sharpening anomalous differences that are near the level of the noise.« less

  4. Characterization of axially tilted fibres utilizing a single-shot interference pattern

    NASA Astrophysics Data System (ADS)

    Sokkar, T. Z. N.; El-Farahaty, K. A.; El-Bakary, M. A.; Omar, E. Z.; Agour, M.

    2017-04-01

    We proposed a method to solve the problem of extracting meaningful phase information for a single-shot interference pattern taken for an axially tilted fibre sample. Conventionally such interference patterns can be not evaluated with appropriate accuracy. Here, such an interference pattern is considered to be a special hologram since it contains information about light propagated through a laterally fixed sample located at different axial planes. Thus, part of the test object in such a hologram is in focus and the other parts are out of focus. The proposed method can be considered as two complementary steps. In the first step the complex amplitude across the hologram plane is recovered using an adaptive spatial carrier frequency method. This is followed by the second step where the complex amplitude is numerically propagated within a given volume. Thus, planes where the test object is in focus are defined. Consequently, the phase distributions corresponding to all of these planes are together stitched. Thus a complete focus phase map for the fiber sample under test is obtained. From the obtained phase map the two dimensions refractive and the two dimensions birefringence of isotactic polypropylene fibre were calculated.

  5. Single-shot measurement of >1010 pulse contrast for ultra-high peak-power lasers

    NASA Astrophysics Data System (ADS)

    Wang, Yongzhi; Ma, Jingui; Wang, Jing; Yuan, Peng; Xie, Guoqiang; Ge, Xulei; Liu, Feng; Yuan, Xiaohui; Zhu, Heyuan; Qian, Liejia

    2014-01-01

    Real-time pulse-contrast observation with a high dynamic range is a prerequisite to tackle the contrast challenge in ultra-high peak-power lasers. However, the commonly used delay-scanning cross-correlator (DSCC) can only provide the time-consumed measurements for repetitive lasers. Single-shot cross-correlator (SSCC) becomes essential in optimizing laser systems and exploring contrast mechanisms. Here we report our progress in developing SSCC towards its practical use. By integrating both the techniques of scattering-noise reduction and sensitive parallel detection into SSCC, we demonstrate a high dynamic range of >1010, which, to our best knowledge, is the first demonstration of an SSCC with a dynamic range comparable to that of commercial DSCCs. The comparison of high-dynamic measurement performances between SSCC and a standard DSCC (Sequoia, Amplitude Technologies) is also carried out on a 200 TW Ti:sapphire laser, and the consistency of results verifies the veracity of our SSCC.

  6. Frequency-Domain Tomography for Single-shot, Ultrafast Imaging of Evolving Laser-Plasma Accelerators

    NASA Astrophysics Data System (ADS)

    Li, Zhengyan; Zgadzaj, Rafal; Wang, Xiaoming; Downer, Michael

    2011-10-01

    Intense laser pulses propagating through plasma create plasma wakefields that often evolve significantly, e.g. by expanding and contracting. However, such dynamics are known in detail only through intensive simulations. Laboratory visualization of evolving plasma wakes in the ``bubble'' regime is important for optimizing and scaling laser-plasma accelerators. Recently snap-shots of quasi-static wakes were recorded using frequency-domain holography (FDH). To visualize the wake's evolution, we have generalized FDH to frequency-domain tomography (FDT), which uses multiple probes propagating at different angles with respect to the pump pulse. Each probe records a phase streak, imprinting a partial record of the evolution of pump-created structures. We then topographically reconstruct the full evolution from all phase streaks. To prove the concept, a prototype experiment visualizing nonlinear index evolution in glass is demonstrated. Four probes propagating at 0, 0.6, 2, 14 degrees to the index ``bubble'' are angularly and temporally multiplexed to a single spectrometer to achieve cost-effective FDT. From these four phase streaks, an FDT algorithm analogous to conventional CT yields a single-shot movie of the pump's self-focusing dynamics.

  7. Truly work-like work extraction via a single-shot analysis

    NASA Astrophysics Data System (ADS)

    Åberg, Johan

    2013-06-01

    The work content of non-equilibrium systems in relation to a heat bath is often analysed in terms of expectation values of an underlying random work variable. However, when optimizing the expectation value of the extracted work, the resulting extraction process is subject to intrinsic fluctuations, uniquely determined by the Hamiltonian and the initial distribution of the system. These fluctuations can be of the same order as the expected work content per se, in which case the extracted energy is unpredictable, thus intuitively more heat-like than work-like. This raises the question of the `truly' work-like energy that can be extracted. Here we consider an alternative that corresponds to an essentially fluctuation-free extraction. We show that this quantity can be expressed in terms of a one-shot relative entropy measure introduced in information theory. This suggests that the relations between information theory and statistical mechanics, as illustrated by concepts like Maxwell's demon, Szilard engines and Landauer's principle, extends to the single-shot regime.

  8. Improved crystal orientation and physical properties from single-shot XFEL stills

    SciTech Connect

    Sauter, Nicholas K. Hattne, Johan; Brewster, Aaron S.; Echols, Nathaniel; Zwart, Petrus H.; Adams, Paul D.

    2014-12-01

    X-ray free-electron laser crystallography relies on the collection of still-shot diffraction patterns. New methods are developed for optimal modeling of the crystals’ orientations and mosaic block properties. X-ray diffraction patterns from still crystals are inherently difficult to process because the crystal orientation is not uniquely determined by measuring the Bragg spot positions. Only one of the three rotational degrees of freedom is directly coupled to spot positions; the other two rotations move Bragg spots in and out of the reflecting condition but do not change the direction of the diffracted rays. This hinders the ability to recover accurate structure factors from experiments that are dependent on single-shot exposures, such as femtosecond diffract-and-destroy protocols at X-ray free-electron lasers (XFELs). Here, additional methods are introduced to optimally model the diffraction. The best orientation is obtained by requiring, for the brightest observed spots, that each reciprocal-lattice point be placed into the exact reflecting condition implied by Bragg’s law with a minimal rotation. This approach reduces the experimental uncertainties in noisy XFEL data, improving the crystallographic R factors and sharpening anomalous differences that are near the level of the noise.

  9. Simultaneous measurement of two ultrashort laser pulses from a single spectrogram in a single shot

    SciTech Connect

    Kane, D.J.; Rodriguez, G.; Taylor, A.J.; Clement, T.S. ||

    1997-04-01

    Frequency-resolved optical gating (FROG) is a technique that produces a spectrogram of an ultrashort laser pulse. The intensity and phase of the ultrashort laser pulse can be determined through solving for the phase of the spectrogram with an iterative, phase-retrieval algorithm. This work presents a new phase-retrieval algorithm that retrieves both the probe and the gate pulses independently by converting the FROG phase-retrieval problem to an eigenvector problem. The new algorithm is robust and general. It is tested theoretically by use of synthetic data sets and experimentally by use of single-shot, polarization-gate FROG. We independently and simultaneously characterize the electric field amplitude and phase of a pulse (probe) that was passed though 200 mm of BK7 glass and the amplitude of an unchanged pulse (gate) from an amplified Ti:sapphire laser. When the effect of the 200 mm of BK7 glass was removed mathematically from the probe, there was good agreement between the measured gate and the calculated, prechirped probe. {copyright} 1997 Optical Society of America

  10. Direct single-shot phase retrieval for separated objects (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Leshem, Ben; Xu, Rui; Miao, Jianwei; Nadler, Boaz; Oron, Dan; Dudovich, Nirit; Raz, Oren

    2016-03-01

    The phase retrieval problem arises in various fields ranging from physics and astronomy to biology and microscopy. Computational reconstruction of the Fourier phase from a single diffraction pattern is typically achieved using iterative alternating projections algorithms imposing a non-convex computational challenge. A different approach is holography, relying on a known reference field. Here we present a conceptually new approach for the reconstruction of two (or more) sufficiently separated objects. In our approach we combine the constraint the objects are finite as well as the information in the interference between them to construct an overdetermined set of linear equations. We show that this set of equations is guaranteed to yield the correct solution almost always and that it can be solved efficiently by standard numerical algebra tools. Essentially, our method combine commonly used constraint (that the object is finite) with a holographic approach (interference information). It differs from holographic methods in the fact that a known reference field is not required, instead the unknown objects serve as reference to one another (hence blind holography). Our method can be applied in a single-shot for two (or more) separated objects or with several measurements with a single object. It can benefit phase imaging techniques such as Fourier phytography microscopy, as well as coherent diffractive X-ray imaging in which the generation of a well-characterized, high resolution reference beam imposes a major challenge. We demonstrate our method experimentally both in the optical domain and in the X-ray domain using XFEL pulses.

  11. Flexible reduced field of view magnetic resonance imaging based on single-shot spatiotemporally encoded technique

    NASA Astrophysics Data System (ADS)

    Li, Jing; Cai, Cong-Bo; Chen, Lin; Chen, Ying; Qu, Xiao-Bo; Cai, Shu-Hui

    2015-10-01

    In many ultrafast imaging applications, the reduced field-of-view (rFOV) technique is often used to enhance the spatial resolution and field inhomogeneity immunity of the images. The stationary-phase characteristic of the spatiotemporally-encoded (SPEN) method offers an inherent applicability to rFOV imaging. In this study, a flexible rFOV imaging method is presented and the superiority of the SPEN approach in rFOV imaging is demonstrated. The proposed method is validated with phantom and in vivo rat experiments, including cardiac imaging and contrast-enhanced perfusion imaging. For comparison, the echo planar imaging (EPI) experiments with orthogonal RF excitation are also performed. The results show that the signal-to-noise ratios of the images acquired by the proposed method can be higher than those obtained with the rFOV EPI. Moreover, the proposed method shows better performance in the cardiac imaging and perfusion imaging of rat kidney, and it can scan one or more regions of interest (ROIs) with high spatial resolution in a single shot. It might be a favorable solution to ultrafast imaging applications in cases with severe susceptibility heterogeneities, such as cardiac imaging and perfusion imaging. Furthermore, it might be promising in applications with separate ROIs, such as mammary and limb imaging. Project supported by the National Natural Science Foundation of China (Grant Nos. 11474236, 81171331, and U1232212).

  12. Single-shot beam size measurements using visible-light interferometry at CESR

    NASA Astrophysics Data System (ADS)

    Wang, S. T.; Holtzapple, R.; Rubin, D. L.

    2017-03-01

    A new primary mirror for a visible-light beam size monitor (vBSM) was designed and installed in the Cornell Electron-Positron Storage Ring (CESR). The vertical angular acceptance of the mirror was doubled to allow double-slit interferometry with large slit separation (>12 mm). In addition, the diffraction associated with the first generation mirror has been eliminated. The resolution of the vertical beam size measurements has been dramatically improved but is ultimately limited by the beam motion. Two fast-response detectors, a Photomultiplier Tube (PMT) array and a gated camera, were employed to study the beam motion. The advantages and limitations of both devices are discussed in this paper. The gated camera was also used to measure single-shot beam width and motion of each bunch in a multi-bunch train. We measured significantly more horizontal motion of electron as compared to positron bunch trains in otherwise identical machine condition. This difference may be a signature for the difference between electron cloud build-up for positron bunch trains versus ions effects characteristic of electron bunch trains.

  13. Direct writing of large-area plasmonic photonic crystals using single-shot interference ablation.

    PubMed

    Pang, Zhaoguang; Zhang, Xinping

    2011-04-08

    We report direct writing of metallic photonic crystals (MPCs) through a single-shot exposure of a thin film of colloidal gold nanoparticles to the interference pattern of a single UV laser pulse before a subsequent annealing process. This is defined as interference ablation, where the colloidal gold nanoparticles illuminated by the bright interference fringes are removed instantly within a timescale of about 6 ns, which is actually the pulse length of the UV laser, whereas the gold nanoparticles located within the dark interference fringes remain on the substrate and form grating structures. This kind of ablation has been proven to have a high spatial resolution and thus enables successful fabrication of waveguided MPC structures with the optical response in the visible spectral range. The subsequent annealing process transforms the grating structures consisting of ligand-covered gold nanoparticles into plasmonic MPCs. The annealing temperature is optimized to a range from 250 to 300 °C to produce MPCs of gold nanowires with a period of 300 nm and an effective area of 5 mm in diameter. If the sample of the spin-coated gold nanoparticles is rotated by 90° after the first exposure, true two-dimensional plasmonic MPCs are produced through a second exposure to the interference pattern. Strong plasmonic resonance and its coupling with the photonic modes of the waveguided MPCs verifies the success of this new fabrication technique. This is the simplest and most efficient technique so far for the construction of large-area MPC devices, which enables true mass fabrication of plasmonic devices with high reproducibility and high success rate.

  14. Single-shot readout of spin qubits in Si/SiGe quantum dots

    NASA Astrophysics Data System (ADS)

    Simmons, Christie

    2012-02-01

    Si/SiGe quantum dots are an attractive option for spin qubit development, because of the long coherence times for electron spins in silicon, arising from weak hyperfine interaction and low spin orbit coupling. I will present measurements of gate-defined single and double quantum dots formed in Si/SiGe semiconductor heterostuctures. Control of the gate voltages on these dots enables tuning of the tunnel coupling to the leads and to other dots. Careful tuning of these tunnel rates, in combination with fast, pulsed-gate manipulation and spin-to-charge conversion, allow spin state measurement using an integrated quantum point contact as a local charge detector. Single spin qubit readout relies on the Zeeman energy splitting from an external magnetic field for spin-to-charge conversion. Two-electron singlet-triplet qubits, on the other hand, can be measured by using Pauli spin blockade of tunneling between the dots to readout the qubit even at zero magnetic field. I will present real-time, single-shot readout measurements of both individual spin [1] and singlet-triplet qubits [2] in gated Si/SiGe quantum dots. Work performed in collaboration with J. R. Prance, Zhan Shi, B. J. Van Bael, Teck Seng Koh, D. E. Savage, M. G. Lagally, R. Joynt, L. R. Schreiber, L. M. K. Vandersypen, M. Friesen, S. N. Coppersmith, and M. A. Eriksson. [4pt] [1] C. B. Simmons et al. Physical Review Letters 106, 156804 (2011). [0pt] [2] J. R. Prance, et al., e-print: http://lanl.arxiv.org/abs/1110.6431

  15. Modulation measuring profilometry with cross grating projection and single shot for dynamic 3D shape measurement

    NASA Astrophysics Data System (ADS)

    Lu, Mingteng; Su, Xianyu; Cao, Yiping; You, Zhisheng; Zhong, Min

    2016-12-01

    In order to determine Dynamic 3-D shape with vertical measurement mode, a fast modulation measuring profilometry (MMP) with a cross grating projection and single shot is proposed. Unlike the previous methods, in our current projection system, one cross grating is projected by a special projection lens consisting of a common projection lens and a cylindrical lens. Due to the characteristics of cylindrical lens, the image of the vertical component and the horizontal component of the cross grating is separated in the image space, and the measuring range is just the space between the two image planes. Through a beam splitter, the CCD camera can coaxially capture the fringe pattern of the cross grating modulated by the testing object's shape. In one fringe pattern, by applying Fourier transform, filtering and inverse Fourier transform, the modulation corresponding to the vertical and horizontal components of the cross grating can be obtained respectively. Then the 3-D shape of the object can be reconstructed according to the mapping relationship between modulation and height, which was established by calibration process in advance. So the 3-D shape information can be recorded at the same speed of the frame rate of the CCD camera. This paper gives the principle of the proposed method and the set-up for measuring experiment and system calibration. The 3-D shape of a still object and a dynamic process of liquid vortex were measured and reconstructed in the experiments, and the results proved the method's feasibility. The advantage of the proposed method is that only one fringe pattern is needed to extract the modulation distribution and to reconstruct the 3-D shape of the object. Therefore, the proposed method can achieve high speed measurement and vertical measurement without shadow and occlusion. It can be used in the dynamic 3-D shape measurement and vibration analysis.

  16. High quality single shot diffraction patterns using ultrashort megaelectron volt electron beams from a radio frequency photoinjector.

    PubMed

    Musumeci, P; Moody, J T; Scoby, C M; Gutierrez, M S; Bender, H A; Wilcox, N S

    2010-01-01

    Single shot diffraction patterns using a 250-fs-long electron beam have been obtained at the UCLA Pegasus laboratory. High quality images with spatial resolution sufficient to distinguish closely spaced peaks in the Debye-Scherrer ring pattern have been recorded by scattering the 1.6 pC 3.5 MeV electron beam generated in the rf photoinjector off a 100-nm-thick Au foil. Dark current and high emittance particles are removed from the beam before sending it onto the diffraction target using a 1 mm diameter collimating hole. These results open the door to the study of irreversible phase transformations by single shot MeV electron diffraction.

  17. Theoretical error analysis of the sampling moiré method and phase compensation methodology for single-shot phase analysis.

    PubMed

    Ri, Shien; Muramatsu, Takashi

    2012-06-01

    Recently, a rapid and accurate single-shot phase measurement technique called the sampling moiré method has been developed for small-displacement distribution measurements. In this study, the theoretical phase error of the sampling moiré method caused by linear intensity interpolation in the case of a mismatch between the sampling pitch and the original grating pitch is analyzed. The periodic phase error is proportional to the square of the spatial angular frequency of the moiré fringe. Moreover, an effective phase compensation methodology is developed to reduce the periodic phase error. Single-shot phase analysis can perform accurately even when the sampling pitch is not matched to the original grating pitch exactly. The primary simulation results demonstrate the effectiveness of the proposed phase compensation methodology.

  18. High quality single shot diffraction patterns using ultrashort megaelectron volt electron beams from a radio frequency photoinjector

    SciTech Connect

    Musumeci, P.; Moody, J. T.; Scoby, C. M.; Gutierrez, M. S.; Bender, H. A.; Wilcox, N. S.

    2010-01-15

    Single shot diffraction patterns using a 250-fs-long electron beam have been obtained at the UCLA Pegasus laboratory. High quality images with spatial resolution sufficient to distinguish closely spaced peaks in the Debye-Scherrer ring pattern have been recorded by scattering the 1.6 pC 3.5 MeV electron beam generated in the rf photoinjector off a 100-nm-thick Au foil. Dark current and high emittance particles are removed from the beam before sending it onto the diffraction target using a 1 mm diameter collimating hole. These results open the door to the study of irreversible phase transformations by single shot MeV electron diffraction.

  19. High Quality Single Shot Diffraction Patterns Using Ultrashort Megaelectron Volt Electron Beams from a Radio Frequency Photoinjector

    SciTech Connect

    P. Musumeci, J. T. Moody, C. M. Scoby, M. S. Gutierrez, H. A. Bender, N. S. Wilcox

    2010-01-01

    Single shot diffraction patterns using a 250 fs long electron beam have been obtained at the UCLA Pegasus laboratory. High quality images with spatial resolution sufficient to distinguish closely spaced peaks in the Debye-Scherrer ring pattern have been recorded by scattering the 1.6 pC 3.5 MeV electron beam generated in the RF photoinjector off a 100 nm thick Au foil. Dark current and high emittance particles are removed from the beam before sending it onto the diffraction target using a 1 mm diameter collimating hole. These results open the door to the study of irreversible phase transformations by single shot MeV electron diffraction

  20. High dynamic range imaging for fringe projection profilometry with single-shot raw data of the color camera

    NASA Astrophysics Data System (ADS)

    Yin, Yongkai; Cai, Zewei; Jiang, Hao; Meng, Xiangfeng; Xi, Jiangtao; Peng, Xiang

    2017-02-01

    It is a challenging issue to get satisfied results in terms of 3D imaging for shiny surface with fringe projection profilometry (FPP), as the wide variation of surface reflectance for shiny surface will lead to bad exposure, which requires the high dynamic range imaging (HDRI) technique. HDRI with monochromatic illumination and single-shot raw data of the color camera is presented in this paper. From the single-shot raw data, 4 monochrome sub-images corresponding to R, G, G and B channels can be separated respectively. After the attenuation ratios between R&G, G&B channels are calibrated, an image with higher dynamic range can be synthesized with the 4 sub-images, which can help to avoid the impact of bad exposure and improve the accuracy of phase calculation. Experiments demonstrate the validity of proposed method for shiny surface.

  1. Cryptotomography: reconstructing 3D Fourier intensities from randomly oriented single-shot diffraction patterns (CXIDB ID 9)

    DOE Data Explorer

    Loh, Ne-Te Duane

    2011-08-01

    These 2000 single-shot diffraction patterns include were either background-scattering only or hits (background-scattering plus diffraction signal from sub-micron ellipsoidal particles at random, undetermined orientations). Candidate hits were identified by eye, and the remainder were presumed as background. 54 usable, background-subtracted hits in this set (procedure in referenced article) were used to reconstruct the 3D diffraction intensities of the average ellipsoidal particle.

  2. Linear modeling of single-shot dual-energy x-ray imaging using a sandwich detector

    NASA Astrophysics Data System (ADS)

    Kim, J.; Kim, D. W.; Kim, S. H.; Yun, S.; Youn, H.; Jeon, H.; Kim, H. K.

    2017-01-01

    For single-shot dual-energy (DE) imaging, a sandwich detector typically consists of a thin front detector and a thick rear detector. Therefore, the spatial-resolution characteristics of the two detectors are different, and as a result, weighted subtraction of the corresponding two images gives rise to edge-enhancement characteristics in the resulting DE images. This is a unique characteristic of single-shot DE imaging compared to the conventional dual-shot DE imaging which uses the same detector to acquire low- and high-energy images. Using a linear-systems theory, in this paper, we show that the modulation-transfer function (MTF) of a sandwich detector is a weighted average of contributions from each MTF characteristic of two detector layers forming the sandwich detector. The MTF results obtained using the developed model are validated with those measured directly from single-shot DE images for an edge-knife phantom. Weighting larger than at least 0.5 in DE reconstruction gives an enhancement in DE MTF at mid and high spatial frequencies compared to the MTFs obtained from each detector layer. The behavior of the linear model as a function of weighting factor used for DE reconstruction is discussed in comparisons with numerical simulations.

  3. Single-shot Zeff dense plasma diagnostic through simultaneous refraction and attenuation measurements with a Talbot–Lau x-ray moiré deflectometer

    DOE PAGES

    Valdivia, M. P.; Stutman, D.; Finkenthal, M.

    2015-03-23

    The Talbot–Lau x-ray moiré deflectometer is a powerful plasma diagnostic capable of delivering simultaneous refraction and attenuation information through the accurate detection of x-ray phase shift and intensity. The diagnostic can provide the index of refraction n = 1 - δ + iβ of an object (dense plasma, for example) placed in the x-ray beam by independently measuring both δ and β, which are directly related to the electron density ne and the attenuation coefficient μ, respectively. Since δ and β depend on the effective atomic number Zeff, a map can be obtained from the ratio between phase and absorptionmore » images acquired in a single shot. The Talbot–Lau x-ray moiré deflectometer and its corresponding data acquisition and processing are briefly described to illustrate how the above is achieved; Zeff values of test objects within the 4–12 range were obtained experimentally through simultaneous refraction and attenuation measurements. We show that Zeff mapping of objects does not require previous knowledge of sample length or shape. The determination of Zeff from refraction and attenuation measurements with Moiré deflectometry could be of high interest to various domains of HED research, such as shocked materials and ICF experiments, as well as material science and NDT.« less

  4. X-Ray Emission Spectrometer Design with Single-Shot Pump-Probe and Resonant Excitation Capabilities

    SciTech Connect

    Spoth, Katherine; /SUNY, Buffalo /SLAC

    2012-08-28

    Core-level spectroscopy in the soft X-ray regime is a powerful tool for the study of chemical bonding processes. The ultrafast, ultrabright X-ray pulses generated by the Linac Coherent Light Source (LCLS) allow these reactions to be studied in greater detail than ever before. In this study, we investigated a conceptual design of a spectrometer for the LCLS with imaging in the non-dispersive direction. This would allow single-shot collection of X-ray emission spectroscopy (XES) measurements with varying laser pump X-ray probe delay or a variation of incoming X-ray energy over the illuminated area of the sample. Ray-tracing simulations were used to demonstrate how the components of the spectrometer affect its performance, allowing a determination of the optimal final design. These simulations showed that the spectrometer's non-dispersive focusing is extremely sensitive to the size of the sample footprint; the spectrometer is not able to image a footprint width larger than one millimeter with the required resolution. This is compatible with a single shot scheme that maps out the laser pump X-ray probe delay in the non-dispersive direction as well as resonant XES applications at normal incidence. However, the current capabilities of the Soft X-Ray (SXR) beamline at the LCLS do not produce the required energy range in a small enough sample footprint, hindering the single shot resonant XES application at SXR for chemical dynamics studies at surfaces. If an upgraded or future beamline at LCLS is developed with lower monochromator energy dispersion the width can be made small enough at the required energy range to be imaged by this spectrometer design.

  5. Femtosecond Single-Shot Imaging of Nanoscale Ferromagnetic Order in Co/Pd Multilayers using Resonant X-ray Holography

    SciTech Connect

    Wang, Tianhan; Zhu, Diling; Benny Wu,; Graves, Catherine; Schaffert, Stefan; Rander, Torbjorn; Muller, leonard; Vodungbo, Boris; Baumier, Cedric; Bernstein, David P.; Brauer, Bjorn; Cros, Vincent; Jong, Sanne de; Delaunay, Renaud; Fognini, Andreas; Kukreja, Roopali; Lee, Sooheyong; Lopez-Flores, Victor; Mohanty, Jyoti; Pfau, Bastian; Popescu, 5 Horia

    2012-05-15

    We present the first single-shot images of ferromagnetic, nanoscale spin order taken with femtosecond x-ray pulses. X-ray-induced electron and spin dynamics can be outrun with pulses shorter than 80 fs in the investigated fluence regime, and no permanent aftereffects in the samples are observed below a fluence of 25 mJ/cm{sup 2}. Employing resonant spatially-muliplexed x-ray holography results in a low imaging threshold of 5 mJ/cm{sup 2}. Our results open new ways to combine ultrafast laser spectroscopy with sequential snapshot imaging on a single sample, generating a movie of excited state dynamics.

  6. Averaging of Replicated Pulses for Enhanced-Dynamic-Range Single-Shot Measurement of Nanosecond Optical Pulses

    SciTech Connect

    Marciante, J.R.; Donaldson, W.R.; Roides, R.G.

    2007-10-04

    Measuring optical pulse shapes beyond the dynamic range of oscilloscopes is achieved by temporal pulse stacking in a low-loss, passive, fiber-optic network. Optical pulses are averaged with their time-delayed replicas without introducing additional noise or jitter, allowing for high-contrast pulse-shape measurements of single-shot events. A dynamic-range enhancement of three bits is experimentally demonstrated and compared with conventional multi-shot averaging. This technique can be extended to yield an increase of up to seven bits of additional dynamic range over nominal oscilloscope performance.

  7. Single-shot three-dimensional shape measurement by low-coherent optical path difference digital holography.

    PubMed

    Tanaka, Yuji; Mori, Yutaka; Nomura, Takanori

    2014-09-20

    A single-shot three-dimensional (3D) shape measurement by low-coherent optical path difference digital holography with small energy consumption is proposed. The use of a superluminescent diode makes it possible. Weighting of the single hologram and numerical reconstruction give the 3D shape of an object. Experimental results using a simple object (the surface of a button cell battery) are given. By comparison with experimental results using a vertical scanning method, the proposed method is confirmed. The effects of a shift interval of the hologram and a zero-order component on a measurement result are also discussed.

  8. Single-shot high aspect ratio bulk nanostructuring of fused silica using chirp-controlled ultrafast laser Bessel beams

    SciTech Connect

    Bhuyan, M. K.; Velpula, P. K.; Colombier, J. P.; Olivier, T.; Faure, N.; Stoian, R.

    2014-01-13

    We report single-shot, high aspect ratio nanovoid fabrication in bulk fused silica using zeroth order chirp-controlled ultrafast laser Bessel beams. We identify a unique laser pulse length and energy dependence of the physical characteristics of machined structures over which nanovoids of diameter in the range 200–400 nm and aspect ratios exceeding 1000 can be fabricated. A mechanism based on the axial energy deposition of nonlinear ultrashort Bessel beams and subsequent material densification or rarefaction in fused silica is proposed, intricating the non-diffractive nature with the diffusing character of laser-generated free carriers. Fluid flow through nanochannel is also demonstrated.

  9. Single-shot, ultrafast diagnostics of light-speed plasma structures and accelerating GeV electrons

    NASA Astrophysics Data System (ADS)

    Chang, Yen-Yu; Shaw, Joseph M.; Welch, James; Weichman, Kathleen; Hannasch, Andrea; LaBerge, Maxwell; Henderson, Watson; Zgadzaj, Rafal; Bernstein, Aaron; Downer, Mike

    2017-03-01

    We have experimentally demonstrated ultrafast diagnostics to visualize the laser wakefield acceleration process in a single-shot mode. We measured the Faraday rotation of a probe pulse due to the magnetic field induced by GeV electrons in low-density plasmas. In addition, we improved the temporal resolution of Frequency Domain Streak Camera (FDSC) to ˜10 fs by broadening the bandwidth of the probe beam, enabling visualization of the bubble dynamics. A prototype experiment using the broad bandwidth FDSC was performed.

  10. Imaging single electrons to enable the generation of ultrashort beams for single-shot femtosecond relativistic electron diffraction

    SciTech Connect

    Li, R. K.; Musumeci, P.; Bender, H. A.; Wilcox, N. S.; Wu, M.

    2011-10-01

    The generation and control of relativistic electron beams well suited for ultrafast electron diffraction application has rapidly advanced, greatly benefiting from the overlap in techniques and expertise with the accelerator community. However, imaging the diffracted MeV electrons with high detection efficiency has remained an under-explored area. In this paper, we report on a quantitative study of the imaging of MeV electrons using a detection system consisting of a phosphor screen, a lens-coupling optics, and a charge-coupled device camera. It is shown that every MeV electron in the beam yields a signal well above the camera noise. With this detection efficiency, only {approx}10{sup 5} electrons per pulse are needed to obtain a high quality single-shot diffraction pattern from a crystalline sample. We measured that such a low charge beam can be as short as 30 fs rms. Further, we discuss the possibility of compressing these electron beams to sub-5 fs rms bunch length by velocity bunching using a short high gradient rf accelerating structure scheduled to be installed next year at the UCLA Pegasus Laboratory. This opens the possibility of single-shot determinations of structural changes in many ultrafast physical processes like nonequilibrium phonon dynamics or relaxation pathways in systems with strong electron-phonon coupling.

  11. Imaging single electrons to enable the generation of ultrashort beams for single-shot femtosecond relativistic electron diffraction

    NASA Astrophysics Data System (ADS)

    Li, R. K.; Musumeci, P.; Bender, H. A.; Wilcox, N. S.; Wu, M.

    2011-10-01

    The generation and control of relativistic electron beams well suited for ultrafast electron diffraction application has rapidly advanced, greatly benefiting from the overlap in techniques and expertise with the accelerator community. However, imaging the diffracted MeV electrons with high detection efficiency has remained an under-explored area. In this paper, we report on a quantitative study of the imaging of MeV electrons using a detection system consisting of a phosphor screen, a lens-coupling optics, and a charge-coupled device camera. It is shown that every MeV electron in the beam yields a signal well above the camera noise. With this detection efficiency, only ˜105 electrons per pulse are needed to obtain a high quality single-shot diffraction pattern from a crystalline sample. We measured that such a low charge beam can be as short as 30 fs rms. Further, we discuss the possibility of compressing these electron beams to sub-5 fs rms bunch length by velocity bunching using a short high gradient rf accelerating structure scheduled to be installed next year at the UCLA Pegasus Laboratory. This opens the possibility of single-shot determinations of structural changes in many ultrafast physical processes like nonequilibrium phonon dynamics or relaxation pathways in systems with strong electron-phonon coupling.

  12. Event-related single-shot volumetric functional magnetic resonance inverse imaging of visual processing.

    PubMed

    Lin, Fa-Hsuan; Witzel, Thomas; Mandeville, Joseph B; Polimeni, Jonathan R; Zeffiro, Thomas A; Greve, Douglas N; Wiggins, Graham; Wald, Lawrence L; Belliveau, John W

    2008-08-01

    Developments in multi-channel radio-frequency (RF) coil array technology have enabled functional magnetic resonance imaging (fMRI) with higher degrees of spatial and temporal resolution. While modest improvement in temporal acceleration has been achieved by increasing the number of RF coils, the maximum attainable acceleration in parallel MRI acquisition is intrinsically limited only by the amount of independent spatial information in the combined array channels. Since the geometric configuration of a large-n MRI head coil array is similar to that used in EEG electrode or MEG SQUID sensor arrays, the source localization algorithms used in MEG or EEG source imaging can be extended to also process MRI coil array data, resulting in greatly improved temporal resolution by minimizing k-space traversal during signal acquisition. Using a novel approach, we acquire multi-channel MRI head coil array data and then apply inverse reconstruction methods to obtain volumetric fMRI estimates of blood oxygenation level dependent (BOLD) contrast at unprecedented whole-brain acquisition rates of 100 ms. We call this combination of techniques magnetic resonance Inverse Imaging (InI), a method that provides estimates of dynamic spatially-resolved signal change that can be used to construct statistical maps of task-related brain activity. We demonstrate the sensitivity and inter-subject reliability of volumetric InI using an event-related design to probe the hemodynamic signal modulations in primary visual cortex. Robust results from both single subject and group analyses demonstrate the sensitivity and feasibility of using volumetric InI in high temporal resolution investigations of human brain function.

  13. Event-related Single-shot Volumetric Functional Magnetic Resonance Inverse Imaging of Visual Processing

    PubMed Central

    Lin, Fa-Hsuan; Witzel, Thomas; Mandeville, Joseph B.; Polimeni, Jonathan R.; Zeffiro, Thomas A.; Greve, Douglas N.; Wiggins, Graham; Wald, Lawrence L.; Belliveau, John W.

    2008-01-01

    Developments in multi-channel radio-frequency (RF) coil array technology have enabled functional magnetic resonance imaging (fMRI) with higher degrees of spatial and temporal resolution. While modest improvement in temporal acceleration has been achieved by increasing the number of RF coils, in parallel data acquisition techniques, the maximum attainable acceleration is intrinsically limited only by the amount of independent spatial information in the combined array channels. Since the geometric configuration of a large-n MRI head coil array is similar to that used in EEG electrode or MEG SQUID sensor arrays, the source localization algorithms used in MEG or EEG source imaging can be extended to also process MRI coil array data, resulting in greatly improved temporal resolution by minimizing k-space traversal during signal acquisition. Using a novel approach, we acquire multi-channel MRI head coil array data and then apply inverse reconstruction methods to obtain volumetric fMRI estimates of blood oxygenation level dependent (BOLD) contrast at unprecedented whole-brain acquisition rates of 100 ms per sample. We call this combination of techniques magnetic resonance Inverse Imaging (InI), a method that provides estimates of dynamic spatially-resolved signal change that can be used to construct statistical maps of task-related brain activity. We demonstrate the sensitivity and inter-subject reliability of volumetric InI using an event-related design to probe the hemodynamic signal modulations in primary visual cortex. Robust results from both single subject and group analyses demonstrate the sensitivity and feasibility of using volumetric InI in high temporal resolution investigations of human brain function. PMID:18538587

  14. Terahertz dielectric response of photoexcited carriers in Si revealed via single-shot optical-pump and terahertz-probe spectroscopy

    SciTech Connect

    Minami, Yasuo; Horiuchi, Kohei; Masuda, Kaisei; Takeda, Jun; Katayama, Ikufumi

    2015-10-26

    We have demonstrated accurate observations of terahertz (THz) dielectric response due to photoexcited carriers in a Si plate via single-shot optical-pump and THz-probe spectroscopy. In contrast to conventional THz time-domain spectroscopy, this spectroscopic technique allows single-shot detection of the THz response of materials at a given delay time between the pump and THz pulses, thereby sufficiently extending the time interval between the pump pulses. As a result, we can accurately measure the dielectric properties of materials, while avoiding artifacts in the response caused by the accumulation of long-lived photoexcited carriers. Using our single-shot scheme, the transmittance of a Si plate was measured in the range of 0.5–2.5 THz with different pump fluences. Based on a Drude model analysis, the optically induced complex dielectric constant, plasma frequency, and damping rate in the THz region were quantitatively evaluated.

  15. High quality single shot ultrafast MeV electron diffraction from a photocathode radio-frequency gun

    SciTech Connect

    Fu, Feichao; Liu, Shengguang; Zhu, Pengfei; Xiang, Dao Zhang, Jie; Cao, Jianming

    2014-08-15

    A compact ultrafast electron diffractometer, consisting of an s-band 1.6 cell photocathode radio-frequency gun, a multi-function changeable sample chamber, and a sensitive relativistic electron detector, was built at Shanghai Jiao Tong University. High-quality single-shot transmission electron diffraction patterns have been recorded by scattering 2.5 MeV electrons off single crystalline gold and polycrystalline aluminum samples. The high quality diffraction pattern indicates an excellent spatial resolution, with the ratio of the diffraction ring radius over the ring rms width beyond 10. The electron pulse width is estimated to be about 300 fs. The high temporal and spatial resolution may open new opportunities in various areas of sciences.

  16. Single-shot mega-electronvolt ultrafast electron diffraction for structure dynamic studies of warm dense matter

    DOE PAGES

    Mo, M. Z.; Shen, X.; Chen, Z.; ...

    2016-08-04

    We have developed a single-shot mega-electronvolt ultrafast-electron-diffraction system to measure the structural dynamics of warm dense matter. The electron probe in this system is featured by a kinetic energy of 3.2 MeV and a total charge of 20 fC, with the FWHM pulse duration and spot size at sample of 350 fs and 120 µm respectively. We demonstrate its unique capability by visualizing the atomic structural changes of warm dense gold formed from a laser-excited 35-nm freestanding single-crystal gold foil. The temporal evolution of the Bragg peak intensity and of the liquid signal during solid-liquid phase transition are quantitatively determined.more » This experimental capability opens up an exciting opportunity to unravel the atomic dynamics of structural phase transitions in warm dense matter regime« less

  17. Single-shot real-time video recording of a photonic Mach cone induced by a scattered light pulse

    PubMed Central

    Liang, Jinyang; Ma, Cheng; Zhu, Liren; Chen, Yujia; Gao, Liang; Wang, Lihong V.

    2017-01-01

    Ultrafast video recording of spatiotemporal light distribution in a scattering medium has a significant impact in biomedicine. Although many simulation tools have been implemented to model light propagation in scattering media, existing experimental instruments still lack sufficient imaging speed to record transient light-scattering events in real time. We report single-shot ultrafast video recording of a light-induced photonic Mach cone propagating in an engineered scattering plate assembly. This dynamic light-scattering event was captured in a single camera exposure by lossless-encoding compressed ultrafast photography at 100 billion frames per second. Our experimental results are in excellent agreement with theoretical predictions by time-resolved Monte Carlo simulation. This technology holds great promise for next-generation biomedical imaging instrumentation. PMID:28116357

  18. Single shot spin readout with a cryogenic high-electron-mobility transistor amplifier at sub-Kelvin temperatures

    DOE PAGES

    Tracy, Lisa A.; Luhman, Dwight R.; Carr, Stephen M.; ...

    2016-02-08

    We use a cryogenic high-electron-mobility transistor circuit to amplify the current from a single electron transistor, allowing for demonstration of single shot readout of an electron spin on a single P donor in Si with 100 kHz bandwidth and a signal to noise ratio of ~9. In order to reduce the impact of cable capacitance, the amplifier is located adjacent to the Si sample, at the mixing chamber stage of a dilution refrigerator. For a current gain of ~2.7 x 103 the power dissipation of the amplifier is 13 μW, the bandwidth is ~1.3 MHz, and for frequencies above 300more » kHz the current noise referred to input is ≤ 70 fA/√Hz. Furthermore, with this amplification scheme, we are able to observe coherent oscillations of a P donor electron spin in isotopically enriched 28Si with 96% visibility.« less

  19. Single shot spin readout with a cryogenic high-electron-mobility transistor amplifier at sub-Kelvin temperatures

    SciTech Connect

    Tracy, Lisa A.; Luhman, Dwight R.; Carr, Stephen M.; Bishop, Nathaniel C.; Ten Eyck, Gregory A.; Pluym, Tammy; Wendt, Joel R.; Lilly, Michael P.; Carroll, Malcolm S.

    2016-02-08

    We use a cryogenic high-electron-mobility transistor circuit to amplify the current from a single electron transistor, allowing for demonstration of single shot readout of an electron spin on a single P donor in Si with 100 kHz bandwidth and a signal to noise ratio of ~9. In order to reduce the impact of cable capacitance, the amplifier is located adjacent to the Si sample, at the mixing chamber stage of a dilution refrigerator. For a current gain of ~2.7 x 103 the power dissipation of the amplifier is 13 μW, the bandwidth is ~1.3 MHz, and for frequencies above 300 kHz the current noise referred to input is ≤ 70 fA/√Hz. Furthermore, with this amplification scheme, we are able to observe coherent oscillations of a P donor electron spin in isotopically enriched 28Si with 96% visibility.

  20. Modelling single shot damage thresholds of multilayer optics for high-intensity short-wavelength radiation sources.

    PubMed

    Loch, R A; Sobierajski, R; Louis, E; Bosgra, J; Bijkerk, F

    2012-12-17

    The single shot damage thresholds of multilayer optics for high-intensity short-wavelength radiation sources are theoretically investigated, using a model developed on the basis of experimental data obtained at the FLASH and LCLS free electron lasers. We compare the radiation hardness of commonly used multilayer optics and propose new material combinations selected for a high damage threshold. Our study demonstrates that the damage thresholds of multilayer optics can vary over a large range of incidence fluences and can be as high as several hundreds of mJ/cm(2). This strongly suggests that multilayer mirrors are serious candidates for damage resistant optics. Especially, multilayer optics based on Li(2)O spacers are very promising for use in current and future short-wavelength radiation sources.

  1. Single-shot thermometry and OH detection via femtosecond fully resonant electronically enhanced CARS (FREE-CARS).

    PubMed

    Wrzesinski, Paul J; Stauffer, Hans U; Schmidt, Jacob B; Roy, Sukesh; Gord, James R

    2016-05-01

    Femtosecond time-resolved, fully resonant electronically enhanced coherent anti-Stokes Raman scattering (FREE-CARS) spectroscopy, incorporating a two-color excitation scheme, is used to demonstrate selective and sensitive gas-phase detection of the hydroxyl (OH) radical in a reacting flow. Spectral resolution of the emitted FREE-CARS signal allows simultaneous detection of temperature and relative OH mole fraction under single-laser-shot conditions in a laminar ethylene-air flame. By comparison to previously reported OH concentration and temperature measurements, we demonstrate excellent single-shot temperature accuracies (∼2% deviation from adiabatic flame temperature) and precisions (∼2% standard deviation), with simultaneous relative OH concentration measurements that demonstrate high detection sensitivity (100-300 ppm).

  2. Polarization-dependent elliptical crater morphologies formed on a silicon surface by single-shot femtosecond laser ablation.

    PubMed

    Ji, Xu; Jiang, Lan; Li, Xiaowei; Han, Weina; Liu, Yang; Huang, Qiang; Lu, Yongfeng

    2014-10-10

    Formation of the elliptical-shaped craters on a silicon surface is investigated comprehensively using a single shot of a femtosecond laser. It is observed that the ablation craters are elongated along the major axis of the polarization direction, while their orientation is parallel to the polarization direction. The ablation area grows and the morphology of the craters evolves from an ellipse to nearly a circle with increasing fluence. The underlying physical mechanism is revealed through numerical simulations that are based on the finite-difference time-domain technique. It is suggested that the initially formed craters or surface defects lead to the redistribution of the electric field on the silicon surface, which plays a crucial role in the creation of the elliptical-shaped craters. In addition, the field intensity becomes enhanced along the incident laser polarization direction, which determines the elliptical crater orientations.

  3. Single Shot Coherence Properties of the Free-Electron Laser SACLA in the Hard X-ray Regime

    PubMed Central

    Lehmkühler, Felix; Gutt, Christian; Fischer, Birgit; Schroer, Martin A.; Sikorski, Marcin; Song, Sanghoon; Roseker, Wojciech; Glownia, James; Chollet, Mathieu; Nelson, Silke; Tono, Kensuke; Katayama, Tetsuo; Yabashi, Makina; Ishikawa, Tetsuya; Robert, Aymeric; Grübel, Gerhard

    2014-01-01

    We measured the coherence properties of the free-electron laser SACLA on a single shot basis at an X-ray energy of 8 keV. By analysing small-angle X-ray scattering speckle patterns from colloidal dispersions we found a degree of transverse coherence of βt = 0.79 ± 0.09. Taking detector properties into account, we developed a simulation model in oder to determine the degree of coherence from intensity histograms. Finally we calculated a coherence time of τc = 0.1 fs and a pulse duration of 5.2 fs which corresponds with previous predictions. PMID:24913261

  4. Improved quantitative phase imaging in lensless microscopy by single-shot multi-wavelength illumination using a fast convergence algorithm.

    PubMed

    Sanz, Martín; Picazo-Bueno, José Angel; García, Javier; Micó, Vicente

    2015-08-10

    We report on a novel algorithm for high-resolution quantitative phase imaging in a new concept of lensless holographic microscope based on single-shot multi-wavelength illumination. This new microscope layout, reported by Noom et al. along the past year and named by us as MISHELF (initials incoming from Multi-Illumination Single-Holographic-Exposure Lensless Fresnel) microscopy, rises from the simultaneous illumination and recording of multiple diffraction patterns in the Fresnel domain. In combination with a novel and fast iterative phase retrieval algorithm, MISHELF microscopy is capable of high-resolution (micron range) phase-retrieved (twin image elimination) biological imaging of dynamic events. In this contribution, MISHELF microscopy is demonstrated through qualitative concept description, algorithm implementation, and experimental validation using both a synthetic object (resolution test target) and a biological sample (swine sperm sample) for the case of three (RGB) illumination wavelengths. The proposed method becomes in an alternative instrument improving the capabilities of existing lensless microscopes.

  5. Single-shot spectro-temporal characterization of XUV pulses from a seeded free-electron laser

    PubMed Central

    De Ninno, Giovanni; Gauthier, David; Mahieu, Benoît; Ribič, Primož Rebernik; Allaria, Enrico; Cinquegrana, Paolo; Danailov, Miltcho Bojanov; Demidovich, Alexander; Ferrari, Eugenio; Giannessi, Luca; Penco, Giuseppe; Sigalotti, Paolo; Stupar, Matija

    2015-01-01

    Intense ultrashort X-ray pulses produced by modern free-electron lasers (FELs) allow one to probe biological systems, inorganic materials and molecular reaction dynamics with nanoscale spatial and femtoscale temporal resolution. These experiments require the knowledge, and possibly the control, of the spectro-temporal content of individual pulses. FELs relying on seeding have the potential to produce spatially and temporally fully coherent pulses. Here we propose and implement an interferometric method, which allows us to carry out the first complete single-shot spectro-temporal characterization of the pulses, generated by an FEL in the extreme ultraviolet spectral range. Moreover, we provide the first direct evidence of the temporal coherence of a seeded FEL working in the extreme ultraviolet spectral range and show the way to control the light generation process to produce Fourier-limited pulses. Experiments are carried out at the FERMI FEL in Trieste. PMID:26290320

  6. High quality single shot ultrafast MeV electron diffraction from a photocathode radio-frequency gun.

    PubMed

    Fu, Feichao; Liu, Shengguang; Zhu, Pengfei; Xiang, Dao; Zhang, Jie; Cao, Jianming

    2014-08-01

    A compact ultrafast electron diffractometer, consisting of an s-band 1.6 cell photocathode radio-frequency gun, a multi-function changeable sample chamber, and a sensitive relativistic electron detector, was built at Shanghai Jiao Tong University. High-quality single-shot transmission electron diffraction patterns have been recorded by scattering 2.5 MeV electrons off single crystalline gold and polycrystalline aluminum samples. The high quality diffraction pattern indicates an excellent spatial resolution, with the ratio of the diffraction ring radius over the ring rms width beyond 10. The electron pulse width is estimated to be about 300 fs. The high temporal and spatial resolution may open new opportunities in various areas of sciences.

  7. Single-shot measurements of laser-induced avalanche breakdown demonstrating spatial and temporal control by an external source

    NASA Astrophysics Data System (ADS)

    Woodbury, Daniel; Wahlstrand, Jared; Goers, Andy; Feder, Linus; Miao, Bo; Hine, George; Salehi, Fatholah; Milchberg, Howard

    2016-10-01

    We report on the use of single-shot supercontinuum spectral interferometry (SSSI) to make temporally and spatially resolved measurements of laser-induced avalanche breakdown in ambient air by a 200 ps pulse. By seeding the breakdown using an external 100 fs pulse, we demonstrate control over the timing and spatial characteristics of the avalanche. In addition, we calculate the collisional ionization rates at various laser intensities and demonstrate seeding of the avalanche breakdown both by multiphoton ionization and by photodetaching ions produced from a radioactive source. These observations provide proof-of-concept support for recent proposals to remotely measure radioactivity using laser-induced avalanche breakdown. This work supported by a DTRA, C-WMD Basic Research Program, and by the DOE NNSA Stewardship Science Graduate Fellowship, provided under Grant Number DE-NA0002135.

  8. Sub-10 ns single-shot dynamic recording in holographic polymeric medium by nonlinear absorption using excited state absorption process

    NASA Astrophysics Data System (ADS)

    Kamada, Kenji; Satoh, Kazuyuki; Tanaka, Yoshito

    2016-09-01

    Optical recording by a single shot of an 8 ns laser pulse in a dye-doped holographic polymeric medium was demonstrated with a peak power as low as 71 W at a wavelength of 402 nm. Nonlinear absorption triggered by two-photon absorption and enhanced by the succeeding process allows high-speed recording corresponding to 125 Mbps (3.4 times the recording speed of a Blu-ray Disc). The preformed holographic grating in the medium enhanced the readout signal through diffraction, resulting in a signal-to-noise ratio of about 15 dB. The recording capacity was estimated at ca. 80 GB/side for 100 µm/side by recording 20 layers, but that of over TB/side class would be possible for optical optimization. Theoretically, it can be improved to 10 TB/side for 800 µm/side by recording 400 layers.

  9. Single-shot, volumetrically illuminated, three-dimensional, tomographic laser-induced-fluorescence imaging in a gaseous free jet.

    PubMed

    Halls, Benjamin R; Thul, Daniel J; Michaelis, Dirk; Roy, Sukesh; Meyer, Terrence R; Gord, James R

    2016-05-02

    Single-shot, tomographic imaging of the three-dimensional concentration field is demonstrated in a turbulent gaseous free jet in co-flow using volumetrically illuminated laser-induced fluorescence. The fourth-harmonic output of an Nd:YAG laser at 266 nm is formed into a collimated 15 × 20 mm2 beam to excite the ground singlet state of acetone seeded into the central jet. Subsequent fluorescence is collected along eight lines of sight for tomographic reconstruction using a combination of stereoscopes optically coupled to four two-stage intensified CMOS cameras. The performance of the imaging system is evaluated and shown to be sufficient for recording instantaneous three-dimensional features with high signal-to-noise (130:1) and nominal spatial resolution of 0.6-1.5 mm at x/D = 7-15.5.

  10. Single-shot mega-electronvolt ultrafast electron diffraction for structure dynamic studies of warm dense matter

    SciTech Connect

    Mo, M. Z.; Shen, X.; Chen, Z.; Li, R. K.; Dunning, M.; Sokolowski-Tinten, K.; Zheng, Q.; Weathersby, S. P.; Reid, A. H.; Coffee, R.; Makasyuk, I.; Edstrom, S.; McCormick, D.; Jobe, K.; Hast, C.; Glenzer, S. H.; Wang, X.

    2016-08-04

    We have developed a single-shot mega-electronvolt ultrafast-electron-diffraction system to measure the structural dynamics of warm dense matter. The electron probe in this system is featured by a kinetic energy of 3.2 MeV and a total charge of 20 fC, with the FWHM pulse duration and spot size at sample of 350 fs and 120 µm respectively. We demonstrate its unique capability by visualizing the atomic structural changes of warm dense gold formed from a laser-excited 35-nm freestanding single-crystal gold foil. The temporal evolution of the Bragg peak intensity and of the liquid signal during solid-liquid phase transition are quantitatively determined. This experimental capability opens up an exciting opportunity to unravel the atomic dynamics of structural phase transitions in warm dense matter regime

  11. Articular cartilage grading of the knee: diagnostic performance of fat-suppressed 3D volume isotropic turbo spin-echo acquisition (VISTA) compared with 3D T1 high-resolution isovolumetric examination (THRIVE).

    PubMed

    Lee, Young Han; Hahn, Seok; Lim, Daekeon; Suh, Jin-Suck

    2017-02-01

    Background Conventionally, two-dimensional (2D) fast spin-echo (FSE) sequences have been widely used for clinical cartilage imaging as well as gradient (GRE) sequences. Recently, three-dimensional (3D) volumetric magnetic resonance imaging (MRI) has been introduced with one 3D volumetric scan, and this is replacing slice-by-slice 2D MR scans. Purpose To evaluate the image quality and diagnostic performance of two 3D sequences for abnormalities of knee cartilage: fat-suppressed (FS) FSE-based 3D volume isotropic turbo spin-echo acquisition (VISTA) and GRE-based 3D T1 high-resolution isovolumetric examination (THRIVE). Material and Methods The institutional review board approved the protocol of this retrospective review. This study enrolled 40 patients (41 knees) with arthroscopically confirmed abnormalities of cartilage. All patients underwent isovoxel 3D-VISTA and 3D-THRIVE MR sequences on 3T MRI. We assessed the cartilage grade on the two 3D sequences using arthroscopy as a gold standard. Inter-observer agreement for each technique was evaluated with the intraclass correlation coefficient (ICC). Differences in the area under the curve (AUC) were compared between the 3D-THRIVE and 3D-VISTA. Results Although inter-observer agreement for both sequences was excellent, the inter-observer agreement for 3D-VISTA was higher than for 3D-THRIVE for cartilage grading in all regions of the knee. There was no significant difference in the diagnostic performance ( P > 0.05) between the two sequences for detecting cartilage grade. Conclusion FSE-based 3D-VISTA images had good diagnostic performance that was comparable to GRE-based 3D-THRIVE images in the evaluation of knee cartilage, and can be used in routine knee MR protocols for the evaluation of cartilage.

  12. Single-Shot Laser Ablation Split-Stream (SS-LASS) Analysis Depth Profiling

    NASA Astrophysics Data System (ADS)

    Kylander-Clark, A. R.; Stearns, M. A.; Viete, D. R.; Cottle, J. M.; Hacker, B. R.

    2014-12-01

    Laser ablation depth profiling of geochronometers—such as zircon, monazite, titanite and rutile—has become popular in recent years as a tool to both determine date vs. depth or trace-element (TE) composition vs. depth; the former allows the dating of thin rims and, potentially, inversion of Pb-loss profiles for thermal histories, whereas the latter can yield insight into changes in PTX or mineral parageneses and inversion of trace-element profiles for thermal histories. In this study, we combine both techniques, enabling simultaneous acquisition of U-Th/Pb isotopic ratios and trace-element compositions, by joining a 193 nm excimer laser to a multi-collector ICP-MS and single-collector ICP-MS. The simultaneous acquisition allows direct shot-by-shot linkage between time and petrology, expanding our ability to understand the evolution of complex geologic systems. We construct each depth profile by capturing the analyte with a succession of individual laser pulses (each ~100 nm deep) . This has two main advantages over a typical time-dependent analysis of a multi-shot routine composed of tens to hundreds of shots and a several μm deep hole. 1) The reference material is analyzed between each shot for a more-accurate standardization of each aliquot of ablated material. 2) There is no mixing of material ablated from successive laser pulses during transmission to the ICP. The method is limited by count rate, which depends on spot size, excavation rate, instrument sensitivity, etc., and, for single-collector ICP, the switching time, which limits the number of elements that can be analyzed and their total counts. We explore the latter theoretically and experimentally to provide insight on both the ideal number of elements to measure and the dwell time in any given sample. Examples of the utility of SS-LASS include the comparison of apparent Pb loss to diffusion profiles of trace elements in rims of metamorphic rutile and titanite, as well as the determination of the

  13. SLM-based tomography of phase objects using single-shot transport of intensity technique

    NASA Astrophysics Data System (ADS)

    Nehmetallah, Georges; Nguyen, Thanh C.; Tran, Dat; Darudi, Ahmad; Soltani, Peyman

    2016-05-01

    Interferometric based techniques are often used for 3D quantitative phase imaging. While these techniques are sensitive to vibrations, non-interferometric intensity based techniques such as the transport of intensity equation (TIE) do not suffer from such a drawback. Phase reconstruction of phase objects using TIE technique is accomplished by recording several diffraction patterns at different observation planes through axially translating the CCD. In this paper, we purpose to use a spatial light modulator (SLM) in a modified 4f TIE optical setup to acquire 3D tomographic images of phase objects. This modified setup will reduce the acquisition time dramatically making the TIE technique useful for dynamic events such as biological samples. We illustrate how 3D phase objects can be reconstructed tomographically by constructing a rotating mechanism for the sample. At each angle of rotation, two diffraction patterns are captured by the CCD either sequentially or instantaneously with the help of a reference mirror. The reconstructed optical fields are tomographically recomposed to yield the final 3D shape using a tomographic backprojection technique. Finally, a reconfigurable hardware controlled by a GUI is employed to synchronize the CCD, the SLM and the rotating stage.

  14. Flow cytometer system for single-shot biosensing based on whispering gallery modes of fluorescent microspheres

    NASA Astrophysics Data System (ADS)

    Lessard, Reno; Rousseau-Cyr, Olivier; Charlebois, Maxime; Riviere, Christophe; Mermut, Ozzy; Allen, Claudine Nı.

    2013-02-01

    We report an innovative label-free biosensor based on statistical analysis of several whispering gallery modes spectral shifts in polystyrene fluorescent microspheres using a custom microflow cytometer. Whispering gallery modes analysis enables detection of nanometer-sized analytes showing promising possibilities for virus, bacteria and molecular detection. To demonstrate this, fluorophore-doped microspheres of the appropriate size parameter are mixed in an aqueous solution. Then, a syringe pump pushes the solution through a fiber optic flow cell where a laser beam illuminates the analysis area to excite the microspheres and their fluorescence is collected. This device provides a low-cost and user friendly solution that could enhance spectrum acquisition rates up to 5 spectra per second thanks to the considerable amount of microspheres flowing through the excitation area per unit time. Finally, the fluorescence spectra are statistically investigated using an instantaneous measurement of apparent refractive index algorithm to determine a reliable value for the refractive index of the environment since the exact radius of the microsphere scanned is unknown. This refractive index becomes an effective value for the local perturbation caused by inhomogeneities on the microsphere surface and hence, determines whether or not inhomogeneities, such as bacteria, are adsorbed by comparing to a control sample. Combining a flow cell with our detection algorithm, we reduce the period of a 50 microspheres experiment from 161 minutes to 14 minutes when the flow rate is 2000 µl/h and the microsphere concentration is 5 µsphere/µl.

  15. Single-Shot Charge Readout Using a Cryogenic Heterojunction Bipolar Transistor Preamplifier Inline with a Silicon Single Electron Transistor at Millikelvin Temperatures

    NASA Astrophysics Data System (ADS)

    Curry, Matthew; England, Troy; Wendt, Joel; Pluym, Tammy; Lilly, Michael; Carr, Stephen; Carroll, Malcolm

    Single-shot readout is a requirement for many implementations of quantum information processing. The single-shot readout fidelity is dependent on the signal-to-noise-ratio (SNR) and bandwidth of the readout detection technique. Several different approaches are being pursued to enhance read-out including RF-reflectometry, RF-transmission, parametric amplification, and transistor-based cryogenic preamplification. The transistor-based cryogenic preamplifier is attractive in part because of the reduced experimental complexity compared with the RF techniques. Here we present single-shot charge readout using a cryogenic Heterojunction-Bipolar-Transistor (HBT) inline with a silicon SET charge-sensor at millikelvin temperatures. For the relevant range of HBT DC-biasing, the current gain is 100 to 2000 and the power dissipation is 50 nW to 5 μW, with the microfabricated SET and discrete HBT in an integrated package mounted to the mixing chamber stage of a dilution refrigerator. We experimentally demonstrate a SNR of up to 10 with a bandwidth of 1 MHz, corresponding to a single-shot time-domain charge-sensitivity of approximately 10-4 e / √Hz. This measured charge-sensitivity is comparable to the values reported using the RF techniques. Sandia National Laboratories is a multi-program laboratory operated by Sandia Corporation, a Lockheed-Martin Company, for the U. S. Department of Energy under Contract No. DE-AC04-94AL85000.

  16. Single-shot Thomson scattering on argon plasmas created by the Microwave Plasma Torch; evidence for a new plasma class

    NASA Astrophysics Data System (ADS)

    van der Mullen, J. J. A. M.; van de Sande, M. J.; de Vries, N.; Broks, B.; Iordanova, E.; Gamero, A.; Torres, J.; Sola, A.

    2007-10-01

    To determine the fine-structure size of plasmas created by a Microwave Plasma Torch (MPT), single-shot Thomson scattering (TS) measurements were performed. The aim was to find a solution for the long-standing discrepancy between experiments and Global Plasma Models (GPMs). Since these GPMs are based on the assumption that (ambipolar) diffusion is the main loss process for charged particles, the diffusion length and thus the fine-structure size should be known with high precision before an appropriate theory-experiment comparison can be carried out. In order to avoid the effect of blurring, which is created during the accumulation of multi-shot TS signals and which obscures the fine-structures, single-shot measurements are indispensable to determine the diffusion length. The results of the present study reveal that the impression created by multi-shot TS that MPT plasmas resemble stable cones is not (always) correct; instead it is found that the plasmas we investigated are tiny filaments that rotate on the mantle of a virtual cone. However, the fine-structure, especially the thickness, of these filaments is not substantially smaller than that of the virtual cone. By applying the theory-experiment comparison to the filament we found that the disagreement is even worse than what we found for the cone. It is therefore inevitable to conclude that the main proposition of the GPM is incorrect. Apparently the plasma is not diffusive in nature; that is, the main loss process of charged particles is not provided by diffusion but by local chemistry. Swirling in a cool nitrogen-containing environment favors the production of molecular ions such as Ar 2+ and N 2+ inside the plasma filament. The destruction of these molecular ions leads to recombination frequencies that are more than a factor 100 larger than what ambipolar diffusion can provide. Thus we are dealing with another plasma class and it is useful to divide plasmas into diffusive and reactive plasmas. The well

  17. LTE turbo decoder design

    NASA Astrophysics Data System (ADS)

    Le, Yang; Tianchun, Ye; Bin, Wu; Ruiqi, Zhang

    2015-07-01

    This paper presents a turbo decoder supporting all 188 block sizes in 3GPP long term evolution (LTE) standard which can be employed in the LTE micro-eNodB system. The design allows 1, 2, 4, 8 or 16 soft-in/soft-out (SISO) decoders to concurrently process each block size, and the number of iterations can be adjusted. By adding a register in core structure add-compare-select-add, this article proposes an improved SISO algorithm and interleaving design, calculated forward state matrix and backward state matrix alternately, and the branch transition probability can be used in the Turbo decode process directly just after one clock delay. The structure enables a decoder processing radix-2 algorithm with high speed, instead of radix-4 as the conventional decoder. Moreover, the paper details an interleaver/de-interleaver, which is combined by two operational steps. One is column address mapping and the other is intra-row permutation. Decoder realizes interleaving by loading data from memories whose address is generated by column mapping and then lets data passing through inter-row permutation. For de-interleaving, the system can adopt reverse operation. Project supported by the LTE-Advanced User Equipment Software Baseband Technology Major Project of China (No. 2013ZX0300315001).

  18. The LHCb Turbo stream

    NASA Astrophysics Data System (ADS)

    Puig, A.

    2016-07-01

    The LHCb experiment will record an unprecedented dataset of beauty and charm hadron decays during Run II of the LHC, set to take place between 2015 and 2018. A key computing challenge is to store and process this data, which limits the maximum output rate of the LHCb trigger. So far, LHCb has written out a few kHz of events containing the full raw sub-detector data, which are passed through a full offline event reconstruction before being considered for physics analysis. Charm physics in particular is limited by trigger output rate constraints. A new streaming strategy includes the possibility to perform the physics analysis with candidates reconstructed in the trigger, thus bypassing the offline reconstruction. In the Turbo stream the trigger will write out a compact summary of physics objects containing all information necessary for analyses. This will allow an increased output rate and thus higher average efficiencies and smaller selection biases. This idea will be commissioned and developed during 2015 with a selection of physics analyses. It is anticipated that the turbo stream will be adopted by an increasing number of analyses during the remainder of LHC Run II (2015-2018) and ultimately in Run III (starting in 2020) with the upgraded LHCb detector.

  19. Flexible Low-power SiGe HBT Amplifier Circuits for Fast Single-shot Spin Readout

    NASA Astrophysics Data System (ADS)

    England, Troy; Lilly, Michael; Curry, Matthew; Carr, Stephen; Carroll, Malcolm

    Fast, low-power quantum state readout is one of many challenges facing quantum information processing. Single electron transistors (SETs) are potentially fast, sensitive detectors for performing spin readout of electrons bound to Si:P donors. From a circuit perspective, however, their output impedance and nonlinear conductance are ill suited to drive the parasitic capacitance of coaxial conductors used in cryogenic environments, necessitating a cryogenic amplification stage. We will introduce two new amplifier topologies that provide excellent gain versus power tradeoffs using silicon-germanium (SiGe) heterojunction bipolar transistors (HBTs). The AC HBT allows in-situ adjustment of power dissipation during an experiment and can provide gain in the millikelvin temperature regime while dissipating less than 500 nW. The AC Current Amplifier maximizes gain at nearly 800 A/A. We will also show results of using these amplifiers with SETs at 4 K. This work was performed, in part, at the Center for Integrated Nanotechnologies, a U.S. DOE Office of Basic Energy Sciences user facility. Sandia National Laboratories is a multi-program laboratory operated by Sandia Corporation, a Lockheed-Martin Company, for the U. S. Department of Energy under Contract No. DE-AC04-94AL85000. Flexible Low-power SiGe HBT Amplifier Circuits for Fast Single-shot Spin Readout.

  20. Development of a Technique for Separating Raman Scattering Signals from Background Emission with Single-Shot Measurement Potential

    NASA Technical Reports Server (NTRS)

    Hartfield, Roy J., Jr.; Dobson, Chris; Eskridge, Richard; Wehrmeyer, Joseph A.

    1997-01-01

    A novel technique for extracting Q-branch Raman signals scattered by a diatomic species from the emission spectrum resulting from the irradiation of combustion products using a broadband excimer laser has been developed. This technique is based on the polarization characteristics of vibrational Raman scattering and can be used for both single-shot Raman extraction and time-averaged data collection. The Q-branch Raman signal has a unique set of polarization characteristics which depend on the direction of the scattering while fluorescence signals are unpolarized. For the present work, a calcite crystal is used to separate the horizonal component of a collected signal from the vertical component. The two components are then sent through a UV spectrometer and imaged onto an intensified CCD camera separately. The vertical component contains both the Raman signal and the interfering fluorescence signal. The horizontal component contains the fluorescence signal and a very weak component of the Raman signal; hence, the Raman scatter can be extracted by taking the difference between the two signals. The separation of the Raman scatter from interfering fluorescence signals is critically important to the interpretation of the Raman for cases in which a broadband ultraviolet (UV) laser is used as an excitation source in a hydrogen-oxygen flame and in all hydrocarbon flames. The present work provides a demonstration of the separation of the Raman scatter from the fluorescence background in real time.

  1. Single-shot Raman spectroscopy and time-resolved reflectivity of a shocked TATB-based explosive

    NASA Astrophysics Data System (ADS)

    Hebert, Philippe; Saint-Amans, Charles; Doucet, Michel; de Resseguier, Thibaut

    2015-06-01

    Single-shot Raman spectroscopy experiments under shockwave loading were performed in order to get information on the initiation mechanisms that can lead to sustained detonation of a TATB-based explosive. Shocks up to 30 GPa were generated using a two-stage laser-driven flyer plate generator. The samples were confined by an optical window and shock pressure was maintained for at least 30 ns. Photon Doppler Velocimetry measurements were performed at the explosive/window interface to determine the shock pressure profile. Raman spectra were recorded as a function of shock pressure and the shifts of the principal modes were compared to static high-pressure measurements performed in a diamond anvil cell. Our shock data indicate the role of temperature effects on the H-bonding network present in TATB. Our Raman spectra also show a progressive extinction of the signal which disappears around 9 GPa. High-speed photography images reveal a simultaneous progressive darkening of the sample surface up to total opacity at 9 GPa. Time-resolved reflectivity measurements under shock compression seem to indicate that this opacity is due to a broadening of the absorption spectrum over the entire visible region.

  2. Single-Shot Scalar-Triplet Measurements in High-Pressure Swirl-Stabilized Flames for Combustion Code Validation

    NASA Technical Reports Server (NTRS)

    Kojima, Jun; Nguyen, Quang-Viet

    2007-01-01

    In support of NASA ARMD's code validation project, we have made significant progress by providing the first quantitative single-shot multi-scalar data from a turbulent elevated-pressure (5 atm), swirl-stabilized, lean direct injection (LDI) type research burner operating on CH4-air using a spatially-resolved pulsed-laser spontaneous Raman diagnostic technique. The Raman diagnostics apparatus and data analysis that we present here were developed over the past 6 years at Glenn Research Center. From the Raman scattering data, we produce spatially-mapped probability density functions (PDFs) of the instantaneous temperature, determined using a newly developed low-resolution effective rotational bandwidth (ERB) technique. The measured 3-scalar (triplet) correlations, between temperature, CH4, and O2 concentrations, as well as their PDF s, also provide a high-level of detail into the nature and extent of the turbulent mixing process and its impact on chemical reactions in a realistic gas turbine injector flame at elevated pressures. The multi-scalar triplet data set presented here provides a good validation case for CFD combustion codes to simulate by providing both average and statistical values for the 3 measured scalars.

  3. Irreversible transformation of ferromagnetic ordered stripe domains in single-shot infrared-pump/resonant-x-ray-scattering-probe experiments

    NASA Astrophysics Data System (ADS)

    Bergeard, Nicolas; Schaffert, Stefan; López-Flores, Víctor; Jaouen, Nicolas; Geilhufe, Jan; Günther, Christian M.; Schneider, Michael; Graves, Catherine; Wang, Tianhan; Wu, Benny; Scherz, Andreas; Baumier, Cédric; Delaunay, Renaud; Fortuna, Franck; Tortarolo, Marina; Tudu, Bharati; Krupin, Oleg; Minitti, Michael P.; Robinson, Joe; Schlotter, William F.; Turner, Joshua J.; Lüning, Jan; Eisebitt, Stefan; Boeglin, Christine

    2015-02-01

    The evolution of a magnetic domain structure upon excitation by an intense, femtosecond infrared (IR) laser pulse has been investigated using single-shot based time-resolved resonant x-ray scattering at the x-ray free electron laser LCLS. A well-ordered stripe domain pattern as present in a thin CoPd alloy film has been used as a prototype magnetic domain structure for this study. The fluence of the IR laser pump pulse was sufficient to lead to an almost complete quenching of the magnetization within the ultrafast demagnetization process taking place within the first few hundreds of femtoseconds following the IR laser pump pulse excitation. On longer time scales this excitation gave rise to subsequent irreversible transformations of the magnetic domain structure. Under our specific experimental conditions, it took about 2 ns before the magnetization started to recover. After about 5 ns the previously ordered stripe domain structure had evolved into a disordered labyrinth domain structure. Surprisingly, we observe after about 7 ns the occurrence of a partially ordered stripe domain structure reoriented into a novel direction. It is this domain structure in which the sample's magnetization stabilizes as revealed by scattering patterns recorded long after the initial pump-probe cycle. Using micromagnetic simulations we can explain this observation based on changes of the magnetic anisotropy going along with heat dissipation in the film.

  4. Turbo fluid machinery and diffusers

    NASA Technical Reports Server (NTRS)

    Sakurai, T.

    1984-01-01

    The general theory behind turbo devices and diffusers is explained. Problems and the state of research on basic equations of flow and experimental and measuring methods are discussed. Conventional centrifugation-type compressor and fan diffusers are considered in detail.

  5. Analysis of slit function errors in single-shot coherent anti-Stokes Raman spectroscopy (CARS) in practical combustors

    SciTech Connect

    Heneghan, S.P.; Vangsness, M.D. )

    1991-09-01

    The temperature determined by a single-shot coherent anti-Stokes Raman spectroscopy (CARS) system is directly related to the half width at half maximum of the instrument slit function. Therefore, an accurate knowledge of the instrument slit function is necessary to determine temperature with CARS. However, in turbulent systems, the input slits of the spectrometer may be removed in order to guarantee signal throughput and establish the necessary dynamic range. In this case, the physical input slits of the spectrometer are replaced with apparent slits created by focussing the input beams near the entrance plane of the spectrometer. The slit function will then depend on the physical relationship among all of the optical components, the probe volume, and the dispersive performance of the spectrometer and detector, as well as the optical path through density and temperature gradients which may not be invariant in a turbulent system. The presence of high temperatures and turbulence levels can effect the size of the CARS signal origin and the optical path, and as a result, the slit function is not invariant. Ignoring these changes can result in large root mean square temperatures (decreased precision) as well as mean temperature errors. The variability of the slit width can be accounted for on a shot-to-shot basis by using a two parameter (HWHM of the slit function and temperature) fitting routine. For temperatures greater than 1200 K there is convergence on a best curve implying both a temperature and a slit width. This method can be used alone or in concert with various weighting schemes to improve the precision. There are two major advantages gained by allowing the slit function to vary in a CARS system: (a) it allows an increase in the precision; (b) it allows temperatures to be calculated without the assumption that the slit function does not change with temperature or turbulence or position within the flame.

  6. In vivo single-shot three-dimensionally localized multiple quantum spectroscopy of GABA in the human brain with improved spectral selectivity

    NASA Astrophysics Data System (ADS)

    Choi, In-Young; Lee, Sang-Pil; Shen, Jun

    2005-01-01

    A single-shot multiple quantum filtering method is developed that uses two double-band frequency selective pulses for enhanced spectral selectivity in combination with a slice-selective 90°, a slice-selective universal rotator 90°, and a spectral-spatial pulse composed of two slice-selective universal rotator 45° pulses for single-shot three-dimensional localization. The use of this selective multiple quantum filtering method for C3 and C4 methylene protons of GABA resulted in improved spectral selectivity for GABA and effective suppression of overlapping signals such as creatine and glutathione in each single scan, providing reliable measurements of the GABA doublet in all subjects. The concentration of GABA was measured to be 0.7 ± 0.2 μmol/g (means ± SD, n = 15) in the fronto-parietal region of the human brain in vivo.

  7. Experimental comparison of single-shot broadband vibrational and dual-broadband pure rotational coherent anti-Stokes Raman scattering in hot air.

    PubMed

    Seeger, T; Leipertz, A

    1996-05-20

    Broadband vibrational and dual-broadband pure rotational coherent anti-Stokes Raman scattering (CARS) have been compared in a high-temperature oven, in which the accuracy and single-shot precision of gas temperature and relative O(2)- and N(2)-concentration measurements in hot air were probed over a temperature range that is typical for many combustion processes. To ensure a realistic comparison, we used nearly the same experimental setup for both CARS techniques. Besides temperature information, dual-broadband pure rotational CARS offers the possibility of achieving simultaneous single-shot concentration measurements. The comparison shows that this technique also has significant advantages in temperature evaluation over a large temperature range in comparison with vibrational CARS.

  8. Self-acousto-optic modulation and orthogonality violation in the transverse modes of a broad-area Nd-doped yttrium-aluminum-garnet single-shot laser

    SciTech Connect

    Soler Rus, M. Odin; Cabrera-Granado, E.; Guerra Perez, J. M.

    2011-05-15

    Self-acousto-optic Raman-Nath modulation and nonorthogonal transversal modes are found in a broad-area Nd:YAG single-shot laser. The device is free from the thermal-induced effects previously related to orthogonality violation and the acousto-optic modulation comes from a shock wave produced by the discharge of the flash lamps that optically pump the laser. The experimental findings are reproduced by a general model of a class B laser.

  9. Distinguishing Micron-Sized UO2, UO3, etc. Particles from Other Common Mineral Particles by Single-Shot Fluorescence Spectra

    SciTech Connect

    Halverson, J.E.

    2003-02-05

    An optical system for detecting the single-shot fluorescence spectrum from a single flowing particle was built. With this system, the single-shot fluorescence spectrum was observed from an individual UO3 particle around 50 um in diameter. The fluorescence spectra from UO2, UO3, U3O8 were centered around 520 nm when excited by a 266 nm or 355 nm laser. The fluorescence spectra from UOx showed different peak wavelengths and different spectral profiles from those of SiO2, Al2O3, CaO, CdO, CrO3, Cr2O3, FeO, Fe2O3, Li2O, PbO, PbO2, and Pb3O4, which could be the main interfering mineral-oxide particles. These differences provide the possibility of a quick and simple method for distinguishing UO2, UO3, U3O8, and other uranium oxide particles from many common mineral-oxide particles. By measuring single-shot, single-particle fluorescence spectra, it also may be possible to monitor the ambient aerosols that are contaminated with uranium oxide in the respiratory size aerosols (1-10 um in diameter).

  10. Turbo-compressor engine

    SciTech Connect

    Rifkin, F.

    1992-02-18

    This patent describes a turbo-compressor engine for a continuous supply of compressed gases. It comprises a first compressor means adapted to compress a body of air and connected to a combustion chamber to pass compressed air thereinto; means to introduce and mix fuel into the compressed air; means to ignite the fuel-air mixture; housing means; an exhaust chamber located in the housing means and defining with the housing means guide means to guide combustion products from the combustion chamber; combustion products turbine means positioned downstream of the combustion means and in communication with the guide means; second compressor means downstream of the turbine means for compressing combustion products and connected to the exhaust chamber, the first and second compressor means and the turbine means being axially aligned on a common shaft, the shaft terminating before the exhaust chamber, and an end plate separating the exhaust chamber from the turbine means, the end plate secured to an end face of the shaft, the turbine means and second compressor means attached to the end plate, forming a rotatable subassembly, and the end plate including openings therethrough adapted to pass combustion products, compressed by second compressor means into the exhaust chamber.

  11. Single-shot single-voxel lactate measurements using FOCI-LASER and a multiple-quantum filter.

    PubMed

    Payne, Geoffrey S; deSouza, Nandita M; Messiou, Christina; Leach, Martin O

    2015-04-01

    Measurement of tissue lactate using (1) H MRS is often confounded by overlap with intense lipid signals at 1.3 ppm. Single-voxel localization using PRESS is also compromised by the large chemical shift displacement between voxels for the 4.1 ppm (-CH) resonance and the 1.3 ppm -CH3 resonance, leading to subvoxels with signals of opposite phase and hence partial signal cancellation. To reduce the chemical shift displacement to negligible proportions, a modified semi-LASER sequence was written ("FOCI-LASER", abbreviated as fLASER) using FOCI pulses to permit high RF bandwidth even with the limited RF amplitude characteristic of clinical MRI scanners. A further modification, MQF-fLASER, includes a selective multiple-quantum filter to detect lactate and reject lipid signals. The sequences were implemented on a Philips 3 T Achieva TX system. In a solution of brain metabolites fLASER lactate signals were 2.7 times those of PRESS. MQF-fLASER lactate was 47% of fLASER (the theoretical maximum is 50%) but still larger than PRESS lactate. In oil, the main 1.3 ppm lipid peak was suppressed to less than 1%. Enhanced suppression was possible using increased gradient durations. The minimum detectable lactate concentration was approximately 0.5 mM. Coherence selection gradients needed to be at the magic angle to avoid large water signals derived from intermolecular multiple-quantum coherences. In pilot patient measurements, lactate peaks were often observed in brain tumours, but not in cervix tumours; lipids were effectively suppressed. In summary, compared with PRESS, the fLASER sequence yields greatly superior sensitivity for direct detection of lactate (and equivalent sensitivity for other metabolites), while the single-voxel single-shot MQF-fLASER sequence surpasses PRESS for lactate detection while eliminating substantial signals from lipids. This sequence will increase the potential for in vivo lactate measurement as a biomarker in targeted anti-cancer treatments as well as

  12. A grating-based single-shot x-ray phase contrast and diffraction method for in vivo imaging

    SciTech Connect

    Bennett, Eric E.; Kopace, Rael; Stein, Ashley F.; Wen Han

    2010-11-15

    Purpose: The purpose of this study is to develop a single-shot version of the grating-based phase contrast x-ray imaging method and demonstrate its capability of in vivo animal imaging. Here, the authors describe the principle and experimental results. They show the source of artifacts in the phase contrast signal and optimal designs that minimize them. They also discuss its current limitations and ways to overcome them. Methods: A single lead grid was inserted midway between an x-ray tube and an x-ray camera in the planar radiography setting. The grid acted as a transmission grating and cast periodic dark fringes on the camera. The camera had sufficient spatial resolution to resolve the fringes. Refraction and diffraction in the imaged object manifested as position shifts and amplitude attenuation of the fringes, respectively. In order to quantify these changes precisely without imposing a fixed geometric relationship between the camera pixel array and the fringes, a spatial harmonic method in the Fourier domain was developed. The level of the differential phase (refraction) contrast as a function of hardware specifications and device geometry was derived and used to guide the optimal placement of the grid and object. Both ex vivo and in vivo images of rodent extremities were collected to demonstrate the capability of the method. The exposure time using a 50 W tube was 28 s. Results: Differential phase contrast images of glass beads acquired at various grid and object positions confirmed theoretical predictions of how phase contrast and extraneous artifacts vary with the device geometry. In anesthetized rats, a single exposure yielded artifact-free images of absorption, differential phase contrast, and diffraction. Differential phase contrast was strongest at bone-soft tissue interfaces, while diffraction was strongest in bone. Conclusions: The spatial harmonic method allowed us to obtain absorption, differential phase contrast, and diffraction images, all from a

  13. Partial turbo detection with reduced complexity

    NASA Astrophysics Data System (ADS)

    Ouardi, Aissa; Djebbari, A.; Bouazza, B. S.

    2011-06-01

    In this article, we propose a novel method for reducing the complexity of the turbo detector MAP (maximum a posteriori). The basic idea consists in turbo detecting a part of intersymbol interference (ISI) after decomposing the channel in two parts. We show that we can reduce the trellis complexity in the turbo process at a certain cost, i.e. performance loss.

  14. Single-shot Zeff dense plasma diagnostic through simultaneous refraction and attenuation measurements with a Talbot–Lau x-ray moiré deflectometer

    SciTech Connect

    Valdivia, M. P.; Stutman, D.; Finkenthal, M.

    2015-03-23

    The Talbot–Lau x-ray moiré deflectometer is a powerful plasma diagnostic capable of delivering simultaneous refraction and attenuation information through the accurate detection of x-ray phase shift and intensity. The diagnostic can provide the index of refraction n = 1 - δ + iβ of an object (dense plasma, for example) placed in the x-ray beam by independently measuring both δ and β, which are directly related to the electron density ne and the attenuation coefficient μ, respectively. Since δ and β depend on the effective atomic number Zeff, a map can be obtained from the ratio between phase and absorption images acquired in a single shot. The Talbot–Lau x-ray moiré deflectometer and its corresponding data acquisition and processing are briefly described to illustrate how the above is achieved; Zeff values of test objects within the 4–12 range were obtained experimentally through simultaneous refraction and attenuation measurements. We show that Zeff mapping of objects does not require previous knowledge of sample length or shape. The determination of Zeff from refraction and attenuation measurements with Moiré deflectometry could be of high interest to various domains of HED research, such as shocked materials and ICF experiments, as well as material science and NDT.

  15. A Virus in Turbo Pascal.

    ERIC Educational Resources Information Center

    Teleky, Heidi Ann; And Others

    1993-01-01

    Addresses why the authors feel it is not inappropriate to teach about viruses in the how-to, hands-on fashion. Identifies the special features of Turbo Pascal that have to be used for the creation of an effective virus. Defines virus, derives its structure, and from this structure is derived the implemented virus. (PR)

  16. Addition of clonidine or fentanyl to local anaesthetics prolongs the duration of surgical analgesia after single shot caudal block in children.

    PubMed

    Constant, I; Gall, O; Gouyet, L; Chauvin, M; Murat, I

    1998-03-01

    Caudal anaesthesia is indicated for surgical procedures lasting less than 90 min. Fentanyl and clonidine are known to prolong postoperative caudal analgesia, but there are no data on their effect on duration of surgical analgesia. We evaluated if the addition of clonidine or fentanyl to local anaesthetics prolonged the duration of surgical analgesia after single shot caudal block in children in a randomized, double-blind study. We studied 64 children, aged 6-108 months, undergoing bilateral correction of vesicoureteral reflux which was expected to last more than 90 min. Patients were allocated to one of four groups: group O received 1 ml kg-1 of a mixture of 0.25% bupivacaine with epinephrine and 1% lidocaine in equal parts; group F received the same mixture of local anaesthetics in addition to fentanyl 1 microgram kg-1; group C received the same mixture of local anaesthetics in addition to clonidine 1.5 micrograms kg-1; and group C + F received the same mixture of local anaesthetics in addition to fentanyl 0.5 microgram kg-1 and clonidine 0.75 microgram kg-1. Single shot caudal block was sufficient in only 57% of children in group O compared with 93% in groups C and F and 86% in group C + F (P = 0.035). Global assessment of anaesthesia, defined as the time from caudal injection to the first administration of analgesic (either during or after surgery), was significantly longer in the three groups of children who received additives compared with local anaesthetics alone (P = 0.035), but there were no differences between the three additive groups. Vomiting was observed only in children who received fentanyl. Addition of clonidine or fentanyl to local anaesthetics prolonged the duration of surgical analgesia of caudal block, allowing single shot caudal anaesthesia to be recommended for surgery lasting 90-150 minutes. Clonidine had some advantages over fentanyl as it did not produce clinically significant side effects.

  17. Single-Shot Ternary Readout of Two-Electron Spin States in a Quantum Dot Using Spin Filtering by Quantum Hall Edge States.

    PubMed

    Kiyama, H; Nakajima, T; Teraoka, S; Oiwa, A; Tarucha, S

    2016-12-02

    We report on the single-shot readout of three two-electron spin states-a singlet and two triplet substates-whose z components of spin angular momentum are 0 and +1, in a gate-defined GaAs single quantum dot. The three spin states are distinguished by detecting spin-dependent tunnel rates that arise from two mechanisms: spin filtering by spin-resolved edge states and spin-orbital correlation with orbital-dependent tunneling. The three states form one ground state and two excited states, and we observe the spin relaxation dynamics among the three spin states.

  18. A single-shot spatial chirp method for measuring initial AC conductivity evolution of femtosecond laser pulse excited warm dense matter

    SciTech Connect

    Chen, Z.; Hering, P.; Brown, S. B.; Curry, C.; Tsui, Y. Y.; Glenzer, S. H.

    2016-09-19

    To study the rapid evolution of AC conductivity from ultrafast laser excited warm dense matter (WDM), a spatial chirp single-shot method is developed utilizing a crossing angle pump-probe configuration. The pump beam is shaped individually in two spatial dimensions so that it can provide both sufficient laser intensity to excite the material to warm dense matter state and a uniform time window of up to 1 ps with sub-100 fs FWHM temporal resolution. Here, temporal evolution of AC conductivity in laser excited warm dense gold was also measured.

  19. A single-shot spatial chirp method for measuring initial AC conductivity evolution of femtosecond laser pulse excited warm dense matter.

    PubMed

    Chen, Z; Hering, P; Brown, S B; Curry, C; Tsui, Y Y; Glenzer, S H

    2016-11-01

    To study the rapid evolution of AC conductivity from ultrafast laser excited warm dense matter (WDM), a spatial chirp single-shot method is developed utilizing a crossing angle pump-probe configuration. The pump beam is shaped individually in two spatial dimensions so that it can provide both sufficient laser intensity to excite the material to warm dense matter state and a uniform time window of up to 1 ps with sub-100 fs FWHM temporal resolution. Temporal evolution of AC conductivity in laser excited warm dense gold was also measured.

  20. Wavefront Analysis of Nonlinear Self-Amplified Spontaneous-Emission Free-Electron Laser Harmonics in the Single-Shot Regime

    SciTech Connect

    Bachelard, R.; Chubar, O.; Mercere, P.; Idir, M.; Couprie, M.E.; Lambert, G.; Zeitoun, Ph.; Kimura, H.; Ohashi, H.; Higashiya, A.; Yabashi, M.; Nagasono, M.; Hara, T. and Ishikawa, T.

    2011-06-08

    The single-shot spatial characteristics of the vacuum ultraviolet self-amplified spontaneous emission of a free electron laser (FEL) is measured at different stages of amplification up to saturation with a Hartmann wavefront sensor. We show that the fundamental radiation at 61.5 nm tends towards a single-mode behavior as getting closer to saturation. The measurements are found in good agreement with simulations and theory. A near diffraction limited wavefront was measured. The analysis of Fresnel diffraction through the Hartmann wavefront sensor hole array also provides some further insight for the evaluation of the FEL transverse coherence, of high importance for various applications.

  1. Pulse shape measurements using single shot-frequency resolved optical gating for high energy (80 J) short pulse (600 fs) laser

    SciTech Connect

    Palaniyappan, S.; Johnson, R.; Shimada, T.; Gautier, D. C.; Letzring, S.; Offermann, D. T.; Fernandez, J. C.; Shah, R. C.; Jung, D.; Hegelich, B. M.; Hoerlein, R.

    2010-10-15

    Relevant to laser based electron/ion accelerations, a single shot second harmonic generation frequency resolved optical gating (FROG) system has been developed to characterize laser pulses (80 J, {approx}600 fs) incident on and transmitted through nanofoil targets, employing relay imaging, spatial filter, and partially coated glass substrates to reduce spatial nonuniformity and B-integral. The device can be completely aligned without using a pulsed laser source. Variations of incident pulse shape were measured from durations of 613 fs (nearly symmetric shape) to 571 fs (asymmetric shape with pre- or postpulse). The FROG measurements are consistent with independent spectral and autocorrelation measurements.

  2. Single-shot analytical assay based on graphene-oxide-modified surface acoustic wave biosensor for detection of single-nucleotide polymorphisms.

    PubMed

    Liu, Xiang; Wang, Jia-Ying; Mao, Xiao-Bing; Ning, Yong; Zhang, Guo-Jun

    2015-09-15

    The combination of a surface acoustic wave (SAW) biosensor with graphene oxide (GO) provides a promising perspective for detecting DNA mutation. The GO-modified SAW biosensor was prepared by conjugating GO onto the SAW chip surface via electrostatic interaction. Afterward, the probe was immobilized on the GO surface, and detection of DNA mutation was realized by hybridization. The hybridization with a variety of targets would yield different mass and conformational changes on the chip surface, causing the different SAW signals in real time. A total of 137 clinical samples were detected by a single-shot analytical assay based on GO-modified SAW biosensor and direct sequencing in parallel. The diagnostic performance (both sensitivity and specificity) of the assay was evaluated with the direct sequencing as a reference testing method. The phase-shift value of three genotypes in 137 clinical samples was significantly different (p < 0.001). Furthermore, testing of diagnostic performance yielded diagnostic sensitivity and specificity of 100% and 88.6% for identifying CT and CC genotype, 98.0% and 96.2% for identifying CT and TT genotype, respectively. The single-shot analytical assay based on the GO-modified SAW biosensor could be exploited as a potential useful tool to identify CYP2D6*10 polymorphisms in clinical practice of personalized medicine.

  3. A comparison study of multishot vs. single-shot DWI-EPI in the neonatal brain: reduced effects of ghosting compared to adults.

    PubMed

    van Pul, Carola; Roos, F George; Derksen, O Sjoerd; Buijs, Jan; Vlaardingerbroek, Marinus T; Kopinga, Klaas; Wijn, Pieter F F

    2004-11-01

    In the neonatal brain, it is important to use a fast imaging technique to acquire all diffusion weighted images (DWI) for apparent diffusion coefficient (ADC) calculation. Taking into account the occurrence of typical echo planar imaging (EPI) artifacts, we have investigated whether single-shot (SSh) or multishot (MSh) DWI-EPI should be preferred. In 14 neonates, 17 adult patients and 5 adult volunteers, DWIs are obtained both with SSh and MSh EPI. The occurrence of artifacts and their influence on the ADC are explored and further quantified using simulations and phantom studies. Two radiologists scored overall image quality and diagnosability of all images. Single-shot and MSh DWI-EPI scored equally well in neonates with respect to overall image quality and diagnosability. In newborns, more motion artifacts in MSh can be noticed while N/2-ghost artifacts in SSh occur less frequently than in adults. Both N/2-ghost and motion artifacts result in significant ADC abnormalities. There is a serious risk that these artifacts will be mistaken for genuine diffusion abnormalities. N/2-ghost artifacts are hardly noticed in the neonatal brain, which might be due to smaller cerebrospinal fluid (CSF) velocity than in adults. Apparent diffusion coefficient values in MSh are unreliable if motion occurs. We conclude that for ADC calculations in neonates SSh DWI-EPI is more reliable than MSh.

  4. Strategies to improve phase-stability of ultrafast swept source optical coherence tomography for single shot imaging of transient mechanical waves at 16 kHz frame rate

    NASA Astrophysics Data System (ADS)

    Song, Shaozhen; Wei, Wei; Hsieh, Bao-Yu; Pelivanov, Ivan; Shen, Tueng T.; O'Donnell, Matthew; Wang, Ruikang K.

    2016-05-01

    We present single-shot phase-sensitive imaging of propagating mechanical waves within tissue, enabled by an ultrafast optical coherence tomography (OCT) system powered by a 1.628 MHz Fourier domain mode-locked (FDML) swept laser source. We propose a practical strategy for phase-sensitive measurement by comparing the phases between adjacent OCT B-scans, where the B-scan contains a number of A-scans equaling an integer number of FDML buffers. With this approach, we show that micro-strain fields can be mapped with ˜3.0 nm sensitivity at ˜16 000 fps. The system's capabilities are demonstrated on porcine cornea by imaging mechanical wave propagation launched by a pulsed UV laser beam, promising non-contact, real-time, and high-resolution optical coherence elastography.

  5. Single-Shot Measurement of Temporally-Dependent Polarization State of Femtosecond Pulses by Angle-Multiplexed Spectral-Spatial Interferometry

    NASA Astrophysics Data System (ADS)

    Lin, Ming-Wei; Jovanovic, Igor

    2016-09-01

    We demonstrate that temporally-dependent polarization states of ultrashort laser pulses can be reconstructed in a single shot by use of an angle-multiplexed spatial-spectral interferometry. This is achieved by introducing two orthogonally polarized reference pulses and interfering them with an arbitrarily polarized ultrafast pulse under measurement. A unique calibration procedure is developed for this technique which facilitates the subsequent polarization state measurements. The accuracy of several reconstructed polarization states is verified by comparison with that obtained from an analytic model that predicts the polarization state on the basis of its method of production. Laser pulses with mJ-level energies were characterized via this technique, including a time-dependent polarization state that can be used for polarization-gating of high-harmonic generation for production of attosecond pulses.

  6. Single-Shot Measurement of Temporally-Dependent Polarization State of Femtosecond Pulses by Angle-Multiplexed Spectral-Spatial Interferometry

    PubMed Central

    Lin, Ming-Wei; Jovanovic, Igor

    2016-01-01

    We demonstrate that temporally-dependent polarization states of ultrashort laser pulses can be reconstructed in a single shot by use of an angle-multiplexed spatial-spectral interferometry. This is achieved by introducing two orthogonally polarized reference pulses and interfering them with an arbitrarily polarized ultrafast pulse under measurement. A unique calibration procedure is developed for this technique which facilitates the subsequent polarization state measurements. The accuracy of several reconstructed polarization states is verified by comparison with that obtained from an analytic model that predicts the polarization state on the basis of its method of production. Laser pulses with mJ-level energies were characterized via this technique, including a time-dependent polarization state that can be used for polarization-gating of high-harmonic generation for production of attosecond pulses. PMID:27596951

  7. Turbo-Brayton Power Converter

    NASA Technical Reports Server (NTRS)

    Breedlove, Jeffrey

    2015-01-01

    Future NASA space missions will require advanced thermal-to-electric power converters that are reliable, efficient, and lightweight. Creare, LLC, is developing a turbo-Brayton power converter that offers high efficiency and specific power. The converter employs gas bearings to provide maintenance free, long-life operation. Discrete components can be packaged to fit optimally with other subsystems, and the converter's continuous gas flow can communicate directly with remote heat sources and heat rejection surfaces without the need for ancillary heat-transfer components and intermediate flow loops. Creare has completed detailed analyses, trade studies, fabrication trials, and preliminary designs for the components and converter assembly. The company is fabricating and testing a breadboard converter.

  8. A novel technique for single-shot energy-resolved 2D x-ray imaging of plasmas relevant for the inertial confinement fusion.

    PubMed

    Labate, L; Köster, P; Levato, T; Gizzi, L A

    2012-10-01

    A novel x-ray diagnostic of laser-fusion plasmas is described, allowing 2D monochromatic images of hot, dense plasmas to be obtained in any x-ray photon energy range, over a large domain, on a single-shot basis. The device (named energy-encoded pinhole camera) is based upon the use of an array of many pinholes coupled to a large area CCD camera operating in the single-photon mode. The available x-ray spectral domain is only limited by the quantum efficiency of scientific-grade x-ray CCD cameras, thus extending from a few keV up to a few tens of keV. Spectral 2D images of the emitting plasma can be obtained at any x-ray photon energy provided that a sufficient number of photons had been collected at the desired energy. Results from recent inertial confinement fusion related experiments will be reported in order to detail the new diagnostic.

  9. En-face sectional imaging using single-shot full-field optical coherence tomography (SS-FF-OCT) based on white light emitting diode (WLED)

    NASA Astrophysics Data System (ADS)

    Anna, Tulsi; Lai, Chih-Ming; Chiou, Arthur; Kuo, Wen-Chuan

    2016-10-01

    This work reports a Linnik type single shot full-field optical coherence tomography (SS-FF-OCT), which uses a fast generalized analytic signal based complex Riesz transform scheme to reconstruct wide area en-face OCT images. The OCT interferometer is illuminated using a single broad band white light emitting diode (WLED) (wavelength range 470- 850nm, central wavelength 650nm) and detection unit is a two-dimensional (2D) charge complementary metal oxide semiconductor (CMOS) camera. The measured axial and lateral resolution (using 4x, NA=0.1 microscope objective) of the present system is 0.9μm and 3.9μm, very close to theoretical values. The measured imaging area using CMOS camera is 2150 x 2150μm2. The feasibility of the system is demonstrated by imaging scattering samples such as onion bulk and plant leaf. The present SS-FF-OCT is compact, fast (Riesz transform based scheme), stable, cost-effective, and provides comparable axial resolution.

  10. Single-shot gas-phase thermometry using pure-rotational hybrid femtosecond/picosecond coherent anti-Stokes Raman scattering.

    PubMed

    Miller, Joseph D; Roy, Sukesh; Slipchenko, Mikhail N; Gord, James R; Meyer, Terrence R

    2011-08-01

    High-repetition-rate, single-laser-shot measurements are important for the investigation of unsteady flows where temperature and species concentrations can vary significantly. Here, we demonstrate single-shot, pure-rotational, hybrid femtosecond/picosecond coherent anti-Stokes Raman scattering (fs/ps RCARS) thermometry based on a kHz-rate fs laser source. Interferences that can affect nanosecond (ns) and ps CARS, such as nonresonant background and collisional dephasing, are eliminated by selecting an appropriate time delay between the 100-fs pump/Stokes pulses and the pulse-shaped 8.4-ps probe. A time- and frequency-domain theoretical model is introduced to account for rotational-level dependent collisional dephasing and indicates that the optimal probe-pulse time delay is 13.5 ps to 30 ps. This time delay allows for uncorrected best-fit N2-RCARS temperature measurements with ~1% accuracy. Hence, the hybrid fs/ps RCARS approach can be performed with kHz-rate laser sources while avoiding corrections that can be difficult to predict in unsteady flows.

  11. Single-shot gas-phase thermometry using pure-rotational hybrid femtosecond/picosecond coherent anti-Stokes Raman scattering

    NASA Astrophysics Data System (ADS)

    Miller, Joseph D.; Roy, Sukesh; Slipchenko, Mikhail N.; Gord, James R.; Meyer, Terrence R.

    2011-08-01

    High-repetition-rate, single-laser-shot measurements are important for the investigation of unsteady flows where temperature and species concentrations can vary significantly. Here, we demonstrate single-shot, pure-rotational, hybrid femtosecond/picosecond coherent anti-Stokes Raman scattering (fs/ps RCARS) thermometry based on a kHz-rate fs laser source. Interferences that can affect nanosecond (ns) and ps CARS, such as nonresonant background and collisional dephasing, are eliminated by selecting an appropriate time delay between the 100-fs pump/Stokes pulses and the pulse-shaped 8.4-ps probe. A time- and frequency-domain theoretical model is introduced to account for rotational-level dependent collisional dephasing and indicates that the optimal probe-pulse time delay is 13.5 ps to 30 ps. This time delay allows for uncorrected best-fit N2-RCARS temperature measurements with ~1% accuracy. Hence, the hybrid fs/ps RCARS approach can be performed with kHz-rate laser sources while avoiding corrections that can be difficult to predict in unsteady flows.

  12. Reflection, phase and en- face sectional imaging of scattering objects using quasi-single-shot wide-field optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Anna, Tulsi; Kimura, Satoshi; Mehta, Dalip Singh; Sato, Manabu

    2015-10-01

    We report a quasi-single-shot wide-field optical coherence tomography system that enables to measure the reflection, phase and en- face OCT images from the same setup using the glass jig. The jig consisting of a wedge glass substrate and a glue dot is contacted to the tissue surfaces, and the data within glue dot is used to reduce the phase noise of the interference signal. The reconstructed image size of the object was 4.0 mm × 4.3 mm. The standard deviation (STD) of the phase variation was minimized by 54 % and obtained to be 0.027 rad for the poke tissue. The corresponding STD in optical path length change was measured to be 1.4 nm. The refractive index of the water and poke tissue at the surface is also evaluated as 1.36 and 1.39, respectively, using reflection intensity images. Further, the en- face sectional images of the tissue sample are also measured.

  13. Measuring single-shot, picosecond optical damage threshold in Ge, Si, and sapphire with a 5.1-μm laser

    SciTech Connect

    Agustsson, R.; Pogorelsky, I.; Arab, E.; Murokh, A.; O"Shea, B.; Ovodenko, A.; Rosenzweig, J.; Solovyov, V.; Tilton, R.

    2015-11-18

    Optical photonic structures driven by picosecond, GW-class lasers are emerging as promising novel sources of electron beams and high quality X-rays. Due to quadratic dependence on wavelength of the laser ponderomotive potential, the performance of such sources scales very favorably towards longer drive laser wavelengths. However, to take full advantage of photonic structures at mid-IR spectral region, it is important to determine optical breakdown limits of common optical materials. To this end, an experimental study was carried out at a wavelength of 5 µm, using a frequency-doubled CO2 laser source, with 5 ps pulse length. Single-shot optical breakdowns were detected and characterized at different laser intensities, and damage threshold values of 0.2, 0.3, and 7.0 J/cm2, were established for Ge, Si, and sapphire, respectively. As a result, the measured damage threshold values were stable and repeatable within individual data sets, and across varying experimental conditions.

  14. Measuring single-shot, picosecond optical damage threshold in Ge, Si, and sapphire with a 5.1-μm laser

    DOE PAGES

    Agustsson, R.; Pogorelsky, I.; Arab, E.; ...

    2015-11-18

    Optical photonic structures driven by picosecond, GW-class lasers are emerging as promising novel sources of electron beams and high quality X-rays. Due to quadratic dependence on wavelength of the laser ponderomotive potential, the performance of such sources scales very favorably towards longer drive laser wavelengths. However, to take full advantage of photonic structures at mid-IR spectral region, it is important to determine optical breakdown limits of common optical materials. To this end, an experimental study was carried out at a wavelength of 5 µm, using a frequency-doubled CO2 laser source, with 5 ps pulse length. Single-shot optical breakdowns were detectedmore » and characterized at different laser intensities, and damage threshold values of 0.2, 0.3, and 7.0 J/cm2, were established for Ge, Si, and sapphire, respectively. As a result, the measured damage threshold values were stable and repeatable within individual data sets, and across varying experimental conditions.« less

  15. On the design of turbo codes

    NASA Technical Reports Server (NTRS)

    Divsalar, D.; Pollara, F.

    1995-01-01

    In this article, we design new turbo codes that can achieve near-Shannon-limit performance. The design criterion for random interleavers is based on maximizing the effective free distance of the turbo code, i.e., the minimum output weight of codewords due to weight-2 input sequences. An upper bound on the effective free distance of a turbo code is derived. This upper bound can be achieved if the feedback connection of convolutional codes uses primitive polynomials. We review multiple turbo codes (parallel concatenation of q convolutional codes), which increase the so-called 'interleaving gain' as q and the interleaver size increase, and a suitable decoder structure derived from an approximation to the maximum a posteriori probability decision rule. We develop new rate 1/3, 2/3, 3/4, and 4/5 constituent codes to be used in the turbo encoder structure. These codes, for from 2 to 32 states, are designed by using primitive polynomials. The resulting turbo codes have rates b/n (b = 1, 2, 3, 4 and n = 2, 3, 4, 5, 6), and include random interleavers for better asymptotic performance. These codes are suitable for deep-space communications with low throughput and for near-Earth communications where high throughput is desirable. The performance of these codes is within 1 dB of the Shannon limit at a bit-error rate of 10(exp -6) for throughputs from 1/15 up to 4 bits/s/Hz.

  16. Ultrafast, Single-Shot Oscilloscope

    DTIC Science & Technology

    2012-05-24

    preserving spectral phase conjugation for compensating chromatic dispersion and self-phase modulation in optical fibers. We extended the application...27709-2211 15. SUBJECT TERMS absorption, continuous optical signal processing, dispersion compensation devices, dispersion-induced lens aberrations ...demonstrated wavelength-preserving spectral phase conjugation for compensating chromatic dispersion and self-phase modulation in optical fibers. We

  17. Development and demonstration of table-top synchronized fast-scan femtosecond time-resolved spectroscopy system by single-shot scan photo detector array

    NASA Astrophysics Data System (ADS)

    Yabushita, Atsushi; Kao, Chih-Hsien; Lee, Yu-Hsien; Kobayashi, Takayoshi

    2015-07-01

    Ultrafast dynamics is generally studied by pump-probe method with laser pulse, which scans optical delay by motorized stage step by step. Using ultrashort laser pulse shorter than typical molecular vibration periods, the pump-probe measurement can study both of electronic dynamics and vibration dynamics simultaneously. The probe wavelength dependence of the ultrafast electronic and vibration dynamics (UEVD) helps us to distinguish the signal contributions from the dynamics of the electronic ground state and that of the electronic excited states, which elucidates primary reaction mechanism after photoexcitation. Meanwhile, the measurement time of UEVD spectroscopy takes too long time to be used in realistic application. In our previous work, we have developed multi-channel lock-in amplifying (MLA) detectors to study UEVD at all probe wavelengths simultaneously, and synchronized it with laser and fast-scan delay stage to scan the data in five seconds. It enabled us to study UEVD spectroscopy even for photo-fragile materials. However, the home-made MLA detectors required for the measurement is expensive and massive in size and weight, thus not suitable for general researchers in the field of ultrafast time-resolved spectroscopy. In the present work, we have developed a table-top synchronized fast-scan femtosecond time-resolved spectroscopy system using single shot scan line CCD. This system measures time-resolved trace at all probe wavelengths simultaneously in five seconds. The CCD-based fast-scan time-resolved spectroscopy system enables us to study ultrafast dynamics of various materials even biomaterials, which have been thought to be hard or even impossible to be studied in previous methods.

  18. Opioids added to local anesthetics for single-shot intrathecal anesthesia in patients undergoing minor surgery: a meta-analysis of randomized trials.

    PubMed

    Pöpping, Daniel M; Elia, Nadia; Marret, Emmanuel; Wenk, Manuel; Tramèr, Martin R

    2012-04-01

    Opioids are widely used as additives to local anesthetics for intrathecal anesthesia. Benefit and risk remain unclear. We systematically searched databases and bibliographies to February 2011 for full reports of randomized comparisons of any opioid added to any intrathecal local anesthetic with the local anesthetic alone in adults undergoing surgery (except cesarean section) and receiving single-shot intrathecal anesthesia without general anesthesia. We included 65 trials (3338 patients, 1932 of whom received opioids) published between 1983 and 2010. Morphine (0.05-2mg) and fentanyl (10-50 μg) added to bupivacaine were the most frequently tested. Duration of postoperative analgesia was prolonged with morphine (weighted mean difference 503 min; 95% confidence interval [CI] 315 to 641) and fentanyl (weighted mean difference 114 min; 95% CI 60 to 168). Morphine decreased the number of patients needing opioid analgesia after surgery and decreased pain intensity to the 12th postoperative hour. Morphine increased the risk of nausea (number needed to harm [NNH] 9.9), vomiting (NNH 10), urinary retention (NNH 6.5), and pruritus (NNH 4.4). Fentanyl increased the risk of pruritus (NNH 3.3). With morphine 0.05 to 0.5mg, the NNH for respiratory depression varied between 38 and 59 depending on the definition of respiratory depression chosen. With fentanyl 10 to 40 μg, the risk of respiratory depression was not significantly increased. For none of these effects, beneficial or harmful, was there evidence of dose-responsiveness. Consequently, minimal effective doses of intrathecal morphine and fentanyl should be sought. For intrathecal buprenorphine, diamorphine, hydromorphone, meperidine, methadone, pentazocine, sufentanil, and tramadol, there were not enough data to allow for meaningful conclusions.

  19. Development of Compton X-ray spectrometer for high energy resolution single-shot high-flux hard X-ray spectroscopy.

    PubMed

    Kojima, Sadaoki; Ikenouchi, Takahito; Arikawa, Yasunobu; Sakata, Shohei; Zhang, Zhe; Abe, Yuki; Nakai, Mitsuo; Nishimura, Hiroaki; Shiraga, Hiroyuki; Ozaki, Tetsuo; Miyamoto, Shuji; Yamaguchi, Masashi; Takemoto, Akinori; Fujioka, Shinsuke; Azechi, Hiroshi

    2016-04-01

    Hard X-ray spectroscopy is an essential diagnostics used to understand physical processes that take place in high energy density plasmas produced by intense laser-plasma interactions. A bundle of hard X-ray detectors, of which the responses have different energy thresholds, is used as a conventional single-shot spectrometer for high-flux (>10(13) photons/shot) hard X-rays. However, high energy resolution (Δhv/hv < 0.1) is not achievable with a differential energy threshold (DET) X-ray spectrometer because its energy resolution is limited by energy differences between the response thresholds. Experimental demonstration of a Compton X-ray spectrometer has already been performed for obtaining higher energy resolution than that of DET spectrometers. In this paper, we describe design details of the Compton X-ray spectrometer, especially dependence of energy resolution and absolute response on photon-electron converter design and its background reduction scheme, and also its application to the laser-plasma interaction experiment. The developed spectrometer was used for spectroscopy of bremsstrahlung X-rays generated by intense laser-plasma interactions using a 200 μm thickness SiO2 converter. The X-ray spectrum obtained with the Compton X-ray spectrometer is consistent with that obtained with a DET X-ray spectrometer, furthermore higher certainly of a spectral intensity is obtained with the Compton X-ray spectrometer than that with the DET X-ray spectrometer in the photon energy range above 5 MeV.

  20. Nonenhanced peripheral MR-angiography (MRA) at 3 Tesla: evaluation of quiescent-interval single-shot MRA in patients undergoing digital subtraction angiography.

    PubMed

    Wagner, Moritz; Knobloch, Gesine; Gielen, Martin; Lauff, Marie-Teres; Romano, Valentina; Hamm, Bernd; Kröncke, Thomas

    2015-04-01

    Quiescent-interval single-shot MRA (QISS-MRA) is a promising nonenhanced imaging technique for assessment of peripheral arterial disease (PAD). Previous studies at 3 Tesla included only very limited numbers of patients for correlation of QISS-MRA with digital subtraction angiography (DSA) as standard of reference (SOR). The aim of this prospective institutional review board-approved study was to compare QISS-MRA at 3 Tesla with DSA in a larger patient group. Our study included 32 consecutive patients who underwent QISS-MRA, contrast-enhanced MRA (CE-MRA), and DSA. Two readers independently performed a per-segment evaluation of QISS-MRA and CE-MRA for image quality and identification of non-significant stenosis (<50%) versus significant stenosis (50-100%). The final dataset included 1,027 vessel segments. Reader 1 and 2 rated image quality as diagnostic in 96.8 and 98.0% of the vessel segments on QISS-MRA and in 99.3 and 98.4% of the vessel segments on CE-MRA, respectively. DSA was available for 922 segments and detected significant stenosis in 133 segments (14.4%). Consensus reading yielded the following diagnostic parameters for QISS-MRA versus CE-MRA: sensitivity: 83.5% (111/133) versus 82.7% (110/133), p = 0.80; specificity: 93.9% (741/789) versus 95.7% (755/789), p = 0.25; and diagnostic accuracy: 92.4% (852/922) versus 93.8% (865/922), p = 0.35. In conclusion, using DSA as SOR, QISS-MRA and CE-MRA at 3 Tesla showed similar diagnostic accuracy in the assessment of PAD. A limitation of QISS-MRA was the lower rate of assessable vessel segments compared to CE-MRA.

  1. Ultrafast crystalline-to-amorphous phase transition in Ge{sub 2}Sb{sub 2}Te{sub 5} chalcogenide alloy thin film using single-shot imaging spectroscopy

    SciTech Connect

    Takeda, Jun Oba, Wataru; Minami, Yasuo; Katayama, Ikufumi; Saiki, Toshiharu

    2014-06-30

    We have observed an irreversible ultrafast crystalline-to-amorphous phase transition in Ge{sub 2}Sb{sub 2}Te{sub 5} chalcogenide alloy thin film using broadband single-shot imaging spectroscopy. The absorbance change that accompanied the ultrafast amorphization was measured via single-shot detection even for laser fluences above the critical value, where a permanent amorphized mark was formed. The observed rise time to reach the amorphization was found to be ∼130–200 fs, which was in good agreement with the half period of the A{sub 1} phonon frequency in the octahedral GeTe{sub 6} structure. This result strongly suggests that the ultrafast amorphization can be attributed to the rearrangement of Ge atoms from an octahedral structure to a tetrahedral structure. Finally, based on the dependence of the absorbance change on the laser fluence, the stability of the photoinduced amorphous phase is discussed.

  2. An Interactive Concatenated Turbo Coding System

    NASA Technical Reports Server (NTRS)

    Liu, Ye; Tang, Heng; Lin, Shu; Fossorier, Marc

    1999-01-01

    This paper presents a concatenated turbo coding system in which a Reed-Solomon outer code is concatenated with a binary turbo inner code. In the proposed system, the outer code decoder and the inner turbo code decoder interact to achieve both good bit error and frame error performances. The outer code decoder helps the inner turbo code decoder to terminate its decoding iteration while the inner turbo code decoder provides soft-output information to the outer code decoder to carry out a reliability-based soft- decision decoding. In the case that the outer code decoding fails, the outer code decoder instructs the inner code decoder to continue its decoding iterations until the outer code decoding is successful or a preset maximum number of decoding iterations is reached. This interaction between outer and inner code decoders reduces decoding delay. Also presented in the paper are an effective criterion for stopping the iteration process of the inner code decoder and a new reliability-based decoding algorithm for nonbinary codes.

  3. 14 CFR 25.1127 - Exhaust driven turbo-superchargers.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Exhaust driven turbo-superchargers. 25.1127 Section 25.1127 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... driven turbo-superchargers. (a) Each exhaust driven turbo-supercharger must be approved or shown to...

  4. 14 CFR 25.1127 - Exhaust driven turbo-superchargers.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Exhaust driven turbo-superchargers. 25.1127 Section 25.1127 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... driven turbo-superchargers. (a) Each exhaust driven turbo-supercharger must be approved or shown to...

  5. 14 CFR 25.1127 - Exhaust driven turbo-superchargers.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Exhaust driven turbo-superchargers. 25.1127 Section 25.1127 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... driven turbo-superchargers. (a) Each exhaust driven turbo-supercharger must be approved or shown to...

  6. 14 CFR 25.1127 - Exhaust driven turbo-superchargers.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Exhaust driven turbo-superchargers. 25.1127 Section 25.1127 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... driven turbo-superchargers. (a) Each exhaust driven turbo-supercharger must be approved or shown to...

  7. 14 CFR 25.1127 - Exhaust driven turbo-superchargers.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Exhaust driven turbo-superchargers. 25.1127 Section 25.1127 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... driven turbo-superchargers. (a) Each exhaust driven turbo-supercharger must be approved or shown to...

  8. Aerodynamic seal assemblies for turbo-machinery

    DOEpatents

    Bidkar, Rahul Anil; Wolfe, Christopher; Fang, Biao

    2015-09-29

    The present application provides an aerodynamic seal assembly for use with a turbo-machine. The aerodynamic seal assembly may include a number of springs, a shoe connected to the springs, and a secondary seal positioned about the springs and the shoe.

  9. Turbo codes for deep-space communications

    NASA Technical Reports Server (NTRS)

    Divsalar, D.; Pollara, F.

    1995-01-01

    Turbo codes were recently proposed by Berrou, Glavieux, and Thitimajshima, and it has been claimed these codes achieve near-Shannon-limit error correction performance with relatively simple component codes and large interleavers. A required E(b)/N(o) of 0.7 dB was reported for a bit error rate of 10(exp -5), using a rate 1/2 turbo code. However, some important details that are necessary to reproduce these results were omitted. This article confirms the accuracy of these claims, and presents a complete description of an encoder/decoder pair that could be suitable for deep-space applications, where lower rate codes can be used. We describe a new simple method for trellis termination, analyze the effect of interleaver choice on the weight distribution of the code, and introduce the use of unequal rate component codes, which yield better performance.

  10. TurboTech Technical Evaluation Automated System

    NASA Technical Reports Server (NTRS)

    Tiffany, Dorothy J.

    2009-01-01

    TurboTech software is a Web-based process that simplifies and semiautomates technical evaluation of NASA proposals for Contracting Officer's Technical Representatives (COTRs). At the time of this reporting, there have been no set standards or systems for training new COTRs in technical evaluations. This new process provides boilerplate text in response to interview style questions. This text is collected into a Microsoft Word document that can then be further edited to conform to specific cases. By providing technical language and a structured format, TurboTech allows the COTRs to concentrate more on the actual evaluation, and less on deciding what language would be most appropriate. Since the actual word choice is one of the more time-consuming parts of a COTRs job, this process should allow for an increase in quantity of proposals evaluated. TurboTech is applicable to composing technical evaluations of contractor proposals, task and delivery orders, change order modifications, requests for proposals, new work modifications, task assignments, as well as any changes to existing contracts.

  11. Noise suppressor for turbo fan jet engines

    NASA Technical Reports Server (NTRS)

    Cheng, D. Y. (Inventor)

    1983-01-01

    A noise suppressor is disclosed for installation on the discharge or aft end of a turbo fan engine. Within the suppressor are fixed annular airfoils which are positioned to reduce the relative velocity between the high temperature fast moving jet exhaust and the low temperature slow moving air surrounding it. Within the suppressor nacelle is an exhaust jet nozzle which constrains the shape of the jet exhaust to a substantially uniform elongate shape irrespective of the power setting of the engine. Fixed ring airfoils within the suppressor nacelle therefore have the same salutary effects irrespective of the power setting at which the engine is operated.

  12. A von Hamos x-ray spectrometer based on a segmented-type diffraction crystal for single-shot x-ray emission spectroscopy and time-resolved resonant inelastic x-ray scattering studies.

    PubMed

    Szlachetko, J; Nachtegaal, M; de Boni, E; Willimann, M; Safonova, O; Sa, J; Smolentsev, G; Szlachetko, M; van Bokhoven, J A; Dousse, J-Cl; Hoszowska, J; Kayser, Y; Jagodzinski, P; Bergamaschi, A; Schmitt, B; David, C; Lücke, A

    2012-10-01

    We report on the design and performance of a wavelength-dispersive type spectrometer based on the von Hamos geometry. The spectrometer is equipped with a segmented-type crystal for x-ray diffraction and provides an energy resolution in the order of 0.25 eV and 1 eV over an energy range of 8000 eV-9600 eV. The use of a segmented crystal results in a simple and straightforward crystal preparation that allows to preserve the spectrometer resolution and spectrometer efficiency. Application of the spectrometer for time-resolved resonant inelastic x-ray scattering and single-shot x-ray emission spectroscopy is demonstrated.

  13. Single-shot echo-planar imaging with Nyquist ghost compensation: interleaved dual echo with acceleration (IDEA) echo-planar imaging (EPI).

    PubMed

    Poser, Benedikt A; Barth, Markus; Goa, Pål-Erik; Deng, Weiran; Stenger, V Andrew

    2013-01-01

    Echo planar imaging (EPI) is most commonly used for blood oxygen level-dependent fMRI, owing to its sensitivity and acquisition speed. A major problem with EPI is Nyquist (N/2) ghosting, most notably at high field. EPI data are acquired under an oscillating readout gradient and hence vulnerable to gradient imperfections such as eddy current delays and off-resonance effects, as these cause inconsistencies between odd and even k-space lines after time reversal. We propose a straightforward and pragmatic method herein termed "interleaved dual echo with acceleration (IDEA) EPI": two k-spaces (echoes) are acquired under the positive and negative readout lobes, respectively, by performing phase encoding blips only before alternate readout gradients. From these two k-spaces, two almost entirely ghost free images per shot can be constructed, without need for phase correction. The doubled echo train length can be compensated by parallel imaging and/or partial Fourier acquisition. The two k-spaces can either be complex averaged during reconstruction, which results in near-perfect cancellation of residual phase errors, or reconstructed into separate images. We demonstrate the efficacy of IDEA EPI and show phantom and in vivo images at both 3 T and 7 T.

  14. The problem of the turbo-compressor

    NASA Technical Reports Server (NTRS)

    Devillers, Rene

    1920-01-01

    In terminating the study of the adaptation of the engine to the airplane, we will examine the problem of the turbo-compressor,the first realization of which dates from the war; this will form an addition to the indications already given on supercharging at various altitudes. This subject is of great importance for the application of the turbo-compressor worked by the exhaust gases. As a matter of fact, a compressor increasing the pressure in the admission manifold may be controlled by the engine shaft by means of multiplication gear or by a turbine operated by the exhaust gas. Assuming that the increase of pressure in the admission manifold is the same in both cases, the pressure in the exhaust manifold would be greater in the case in which the compressor is worked by the exhaust gas and there would result a certain reduction of engine power which we must be able to calculate. On the other hand , if the compressor is controlled by the engine shaft, a certain fraction of the excess power supplied is utilized for the rotation of the compressor. In order to compare the two systems, it is there-fore necessary to determine the value of the reduction of power due to back pressure when the turbine is employed.

  15. Turbo-generator control with variable valve actuation

    DOEpatents

    Vuk, Carl T [Denver, IA

    2011-02-22

    An internal combustion engine incorporating a turbo-generator and one or more variably activated exhaust valves. The exhaust valves are adapted to variably release exhaust gases from a combustion cylinder during a combustion cycle to an exhaust system. The turbo-generator is adapted to receive exhaust gases from the exhaust system and rotationally harness energy therefrom to produce electrical power. A controller is adapted to command the exhaust valve to variably open in response to a desired output for the turbo-generator.

  16. Progress of High Efficiency Centrifugal Compressor Simulations Using TURBO

    NASA Technical Reports Server (NTRS)

    Kulkarni, Sameer; Beach, Timothy A.

    2017-01-01

    Three-dimensional, time-accurate, and phase-lagged computational fluid dynamics (CFD) simulations of the High Efficiency Centrifugal Compressor (HECC) stage were generated using the TURBO solver. Changes to the TURBO Parallel Version 4 source code were made in order to properly model the no-slip boundary condition along the spinning hub region for centrifugal impellers. A startup procedure was developed to generate a converged flow field in TURBO. This procedure initialized computations on a coarsened mesh generated by the Turbomachinery Gridding System (TGS) and relied on a method of systematically increasing wheel speed and backpressure. Baseline design-speed TURBO results generally overpredicted total pressure ratio, adiabatic efficiency, and the choking flow rate of the HECC stage as compared with the design-intent CFD results of Code Leo. Including diffuser fillet geometry in the TURBO computation resulted in a 0.6 percent reduction in the choking flow rate and led to a better match with design-intent CFD. Diffuser fillets reduced annulus cross-sectional area but also reduced corner separation, and thus blockage, in the diffuser passage. It was found that the TURBO computations are somewhat insensitive to inlet total pressure changing from the TURBO default inlet pressure of 14.7 pounds per square inch (101.35 kilopascals) down to 11.0 pounds per square inch (75.83 kilopascals), the inlet pressure of the component test. Off-design tip clearance was modeled in TURBO in two computations: one in which the blade tip geometry was trimmed by 12 mils (0.3048 millimeters), and another in which the hub flow path was moved to reflect a 12-mil axial shift in the impeller hub, creating a step at the hub. The one-dimensional results of these two computations indicate non-negligible differences between the two modeling approaches.

  17. Nonlinear bubble nucleation and growth following filament and white-light continuum generation induced by a single-shot femtosecond laser pulse into dielectrics based on consideration of the time scale

    SciTech Connect

    Mizushima, Yuki; Saito, Takayuki

    2015-09-14

    Bubble nucleation and growth following plasma channeling (filament) and white-light continuum in liquid irradiated by a single-shot fs-pulse were experimentally investigated with close observation of the time scale. Making full use of a new confocal system and time-resolved visualization techniques, we obtained evidence suggestive of a major/minor role of the non-linear/thermal effects during the fs-pulse-induced bubble's fountainhead (10{sup −13} s) and growth (10{sup −7} s), which was never observed with the use of the ns-pulse (i.e., optic cavitation). In this context, the fs-pulse-induced bubble is not an ordinary optic cavitation but rather is nonlinear-optic cavitation. We present the intrinsic differences in the dominant-time domain of the fs-pulse and ns-pulse excitation, and intriguingly, a mere hundred femtoseconds' excitation predetermines the size of the bubble appearing several microseconds after irradiation. That is, the nucleation happens temporally beyond a six-order-of-magnitude difference.

  18. Turbo Pump Fed Micro-Rocket Engine

    NASA Astrophysics Data System (ADS)

    Miotti, P.; Tajmar, M.; Seco, F.; Guraya, C.; Perennes, F.; Soldati, A.; Lang, M.

    2004-10-01

    Micro-satellites (from 10kg up to 100kg) have mass, volume, and electrical power constraints due to their low dimensions. These limitations lead to the lack in currently available active orbit control systems in micro-satellites. Therefore, a micro-propulsion system with a high thrust to mass ratio is required to increase the potential functionality of small satellites. Mechatronic is presently working on a liquid bipropellant micro-rocket engine under contract with ESA (Contract No.16914/NL/Sfe - Micro-turbo-machinery Based Bipropellant System Using MNT). The advances in Mechatronic's project are to realise a micro-rocket engine with propellants pressurised by micro-pumps. The energy for driving the pumps would be extracted from a micro-turbine. Cooling channels around the nozzle would be also used in order to maintain the wall material below its maximum operating temperature. A mass budget comparison with more traditional pressure-fed micro-rockets shows a real benefit from this system in terms of mass reduction. In the paper, an overview of the project status in Mechatronic is presented.

  19. TurboBrayton Cryocooler: A Flight Worthy and Promising Future

    NASA Technical Reports Server (NTRS)

    Gibbon, Judith A.; Swift, Walt L.; Zagarola, Mark V.; DiPirro, Mike; Whitehouse, Paul

    1999-01-01

    A new development in cryocooler technology, a reverse TurboBrayton cycle cryocooler, developed by Creare, Inc. of Hanover, NH, has now been flight tested. This cooler provides high reliability and long life. With no linear moving components common in current flight cryocoolers, the TurboBrayton cooler requires no active control systems to provide a vibration-free signature. The cooler provides first stage cooling for advanced cryogenic systems and serves as a direct replacement for stored cryogen systems with a longer lifetime. Following a successful flight on STS-95, a TurboBrayton cryocooler will be flown on Hubble Space Telescope (HST) in 2000 to provide renewed refrigeration capability for the Near Infrared Camera and Multi-Object Spectrometer (NICMOS). The TurboBrayton cycle cooler is a promising technology already being considered for additional flight programs such as Next Generation Space Telescope (NGST) and Constellation X. These future missions require an advanced generation of the cooler that is currently under development to provide cooling at 10K and less. This paper presents an overview of the current generation cooler with recent flight test results and details the current plans and development progress on the next generation TurboBrayton technology for future missions.

  20. Single Shot Hugoniots of Toluene and Methanol

    NASA Astrophysics Data System (ADS)

    Bolme, C. A.; Eakins, D. E.; Funk, D. J.; McGrane, S. D.; Moore, D. S.; Whitley, V. H.

    2009-12-01

    Ultrafast dynamic ellipsometry was used to acquire shock and particle velocities and shocked refractive indices for toluene and methanol. The liquids were driven with a shock wave that was approximately 300 ps in duration, and the data for each was acquired in a single laser shot by utilizing the Gaussian spatial profile of the drive laser beam to create a range of pressures in the samples. The Hugoniot data match well with previous shock data and with Woolfolk's "universal liquid Hugoniot." The shocked refractive indices of both liquids deviate from the Gladstone-Dale relation, the value expected exclusively from a change in density.

  1. Development of Intake Swirl Generators for Turbo Jet Engine Testing

    DTIC Science & Technology

    1987-03-01

    As a test object a Larxac 04 turbofan engine was chosen which is used as propulsion in the Alpha Jet aircraft . This twospool engine features a two...a__ OPI: !’fIC-TID N .18.1 DEVELOPMENT OF NAR 8WZRL GENERATORS FOR TURBO JET ENGINE TU TING by H.P. Gensmlor*, W. Meyer**, L. Fottner*** Dipl.-Ing...at the Universitit der Bundeswehr MUnchen. The test facility is designed for turbo jet engines up to an maximum thrust of 30kN and a maximum mass

  2. Readout-segmented echo-planar diffusion-weighted imaging in the assessment of orbital tumors: comparison with conventional single-shot echo-planar imaging in image quality and diagnostic performance.

    PubMed

    Xu, Xiaoquan; Wang, Yanjun; Hu, Hao; Su, Guoyi; Liu, Hu; Shi, Haibin; Wu, Feiyun

    2017-01-01

    Background Readout-segmented echo-planar imaging (RS-EPI) could improve the imaging quality of diffusion-weighted imaging (DWI) in various organs. However, whether it could improve the imaging quality and diagnostic performance for the patients with orbital tumors is still unknown. Purpose To compare the image quality and diagnostic performance of RS-EPI DWI with that of conventional single-shot EPI (SS-EPI) DWI in patients with orbital tumors. Material and Methods SS-EPI and RS-EPI DW images of 32 patients with pathologically diagnosed orbital tumors were retrospectively analyzed. Qualitative imaging parameters (imaging sharpness, geometric distortion, ghosting artifacts, and overall imaging quality) and quantitative imaging parameters (apparent diffusion coefficient [ADC], signal-to-noise ratio [SNR], contrast, and contrast-to-noise ratio [CNR]) were assessed by two independent radiologists, and compared between SS-EPI and RS-EPI DWI. Receiver operating characteristic curves were used to determine the diagnostic value of ADC in differentiating malignant from benign orbital tumors. Results RS-EPI DW imaging produced less geometric distortion and ghosting artifacts, and better imaging sharpness and overall imaging quality than SS-EPI DWI (for all, P < 0.001). Meanwhile, RS-EPI DWI produced significantly lower SNR ( P < 0.001) and ADC ( P < 0.001), and higher contrast ( P < 0.001) than SS-EPI DWI, while producing no difference in CNR ( P = 0.137). There was no significant difference on the diagnostic performance between SS-EPI and RS-EPI DWI, when using ADC as the differentiating index ( P = 0.529). Conclusion Compared with SS-EPI, RS-EPI DWI provided significantly better imaging quality and comparable diagnostic performance in differentiating malignant from benign orbital tumors.

  3. Turbo recognition: a statistical approach to layout analysis

    NASA Astrophysics Data System (ADS)

    Tokuyasu, Taku A.; Chou, Philip A.

    2000-12-01

    Turbo recognition (TR) is a communication theory approach to the analysis of rectangular layouts, in the spirit of Document Image Decoding. The TR algorithm, inspired by turbo decoding, is based on a generative model of image production, in which two grammars are used simultaneously to describe structure in orthogonal (horizontal and vertical directions. This enables TR to strictly embody non-local constraints that cannot be taken into account by local statistical methods. This basis in finite state grammars also allows TR to be quickly retargetable to new domains. We illustrate some of the capabilities of TR with two examples involving realistic images. While TR, like turbo decoding, is not guaranteed to recover the statistically optimal solution, we present an experiment that demonstrates its ability to produce optimal or near-optimal results on a simple yet nontrivial example, the recovery of a filled rectangle in the midst of noise. Unlike methods such as stochastic context free grammars and exhaustive search, which are often intractable beyond small images, turbo recognition scales linearly with image size, suggesting TR as an efficient yet near-optimal approach to statistical layout analysis.

  4. Turtlegraphics: A Comparison of Logo and Turbo Pascal.

    ERIC Educational Resources Information Center

    VanLengen, Craig A.

    1989-01-01

    The integrated compiler of the Turbo Pascal environment allows the execution of a completed program independent of the developed environment and with greater execution speed, in comparison with LOGO. Conversion table of turtle-graphic commands for the two languages is presented. (Author/YP)

  5. Neon turbo-Brayton cycle refrigerator for HTS power machines

    NASA Astrophysics Data System (ADS)

    Hirai, Hirokazu; Hirokawa, M.; Yoshida, Shigeru; Nara, N.; Ozaki, S.; Hayashi, H.; Okamoto, H.; Shiohara, Y.

    2012-06-01

    We developed a prototype turbo-Brayton refrigerator whose working fluid is neon gas. The refrigerator is designed for a HTS (High Temperature Superconducting) power transformer and its cooling power is more than 2 kW at 65 K. The refrigerator has a turboexpander and a turbo-compressor, which utilize magnetic bearings. These rotational machines have no rubbing parts and no oil-components. Those make a long maintenance interval of the refrigerator. The refrigerator is very compact because our newly developed turbo-compressor is volumetrically smaller than a displacement type compressor in same operating specification. Another feature of the refrigerator is a wide range operation capability for various heat-loads. Cooling power is controlled by the input-power of the turbo-compressor instead of the conventional method of using an electric heater. The rotational speed of the compressor motor is adjusted by an inverter. This system is expected to be more efficient. We show design details, specification and cooling test results of the new refrigerator in this paper.

  6. Which is your choice for prolonging the analgesic duration of single-shot interscalene brachial blocks for arthroscopic shoulder surgery? intravenous dexamethasone 5 mg vs. perineural dexamethasone 5 mg randomized, controlled, clinical trial.

    PubMed

    Chun, Eun Hee; Kim, Youn Jin; Woo, Jae Hee

    2016-06-01

    The aim of this study was to compare the effect of intravenous (I.V.) dexamethasone with that of perineural dexamethasone on the prolongation of analgesic duration of single-shot interscalene brachial plexus blocks (SISB) in patients undergoing arthroscopic shoulder surgery. We performed a prospective, randomized, double-blind, placebo-controlled study. Patients undergoing elective arthroscopic shoulder surgery with ultrasound-guided SISB were enrolled and randomized into 2 groups. A total volume of 12 mL of the study drug was prepared with a final concentration of 0.5% ropivacaine. In the I.V. group, patients received SISB using ropivacaine 5 mg mL with normal saline (control) with dexamethasone 5 mg I.V. injection. In the perineural group, patients received SISB using ropivacaine 5 mg mL with dexamethasone 5 mg, with normal saline 1 mL I.V. injection. The primary outcome was the time to the first analgesic request, defined as the time between the end of the operation and the first request of analgesics by the patient. The secondary outcomes included patient satisfaction scores, side effects, and neurological symptoms. Patients were randomly assigned to 1 of the 2 groups using a computer-generated randomization table. An anesthesiologist blinded to the group assignments prepared the solutions for injection. The patients and the investigator participating in the study were also blinded to the group assignments. One hundred patients were randomized. Data were analyzed for 99 patients. One case in the I.V. group was converted to open surgery and was therefore not included in the study. Perineural dexamethasone significantly prolonged analgesic duration (median, standard error: 1080 minutes, 117.5 minutes) compared with I.V. dexamethasone (810 minutes, 48.1 minutes) (P = 0.02). There were no significant differences in side effects, neurological symptoms, or changes in blood glucose values between the 2 groups. Our results show that perineural

  7. Contrast-enhanced dynamic MR nephrography using the TurboFLASH navigator-gating technique in children.

    PubMed

    Boss, Andreas; Schaefer, Juergen F; Martirosian, Petros; Hacker, Hans-Walter; Darge, Kassa; Claussen, Claus D; Küper, Klaus; Schick, Fritz; Schlemmer, Heinz-Peter

    2006-07-01

    The purpose of this work was to test the feasibility of an MR examination protocol for the comprehensive assessment of renal morphology, excretion and split renal function using a navigator-gated TurboFLASH sequence. A navigator-gated T1-weighted single-slice TurboFLASH sequence suitable for dynamic MR urography and nephrography was implemented. A protocol was developed allowing for assessment of urinary excretion and split renal function by recording the renal clearance of a gadolinium (Gd) diethylene-triamine-pentacetic-acid (DTPA) bolus. Ten patients aged between 14 months and 14 years (mean age 4.8+/-4.6 years) were evaluated with the following indications: pelvicalyceal dilatation (n=4), follow-up after pyeloplasty (n=1), duplex systems (n=3), large renal cyst (n=1), and renal insufficiency (n=1). Dynamic MR urography and MR split renal function were compared to MAG3 scintigraphy. Evaluation of morphology, excretion and function required 50-60 minutes examination time, plus 10 minutes for post-processing. The TurboFLASH sequence yielded image acquisition at nearly identical diaphragm positions allowing for accurate region-of-interest evaluation within the renal parenchyma and the urinary passage. Static and dynamic MR urography showed the morphology of the urinary tract and excretion with sufficient diagnostic imaging quality, and the results were in diagnostic compliance with scintigraphy. MRI and scintigraphy yielded similar results for split renal function with a correlation coefficient of R=0.968 determined by linear regression. Our conclusions were that the method is robust, easy to perform on a clinical 1.5 T MRI system, rapid to evaluate and post-process and, therefore, easy to incorporate into clinical routine. Compared to scintigraphy, the higher spatial resolution of the MR examination provides additional important information improving the management of the pediatric patients without the application of radioactive tracers.

  8. Multiple turbo codes for deep-space communications

    NASA Technical Reports Server (NTRS)

    Divsalar, D.; Pollara, F.

    1995-01-01

    In this article, we introduce multiple turbo codes and a suitable decoder structure derived from an approximation to the maximum a posteriori probability (MAP) decision rule, which is substantially different from the decoder for two-code-based encoders. We analyze the effect of interleaver choice on the weight distribution of the code, and we describe simulation results on the improved performance of these new codes.

  9. High-capacity turbo-Brayton cryocoolers for space applications

    NASA Astrophysics Data System (ADS)

    Zagarola, Mark V.; McCormick, John A.

    2006-02-01

    Long-life, high-capacity cryocoolers may be needed for future space systems utilizing stored cryogens. The cooling requirements for planetary and extraterrestrial exploration missions, extended-life orbital transfer vehicles, and space depots may range from 10 W to 50 W at temperatures between 20 K and 120 K. Turbo-Brayton cryocoolers are ideal for these systems because they are lightweight, compact and very efficient at high cooling loads due to the high power density of rotary machines. These benefits are in addition to their inherent attributes of high reliability; negligible vibration; long, maintenance-free lifetimes; flexibility in integrating with spacecraft systems; and ability to directly cool remote and distributed loads. To date, space-borne turbo-Brayton technology has been developed for low cooling loads. The first space implementation of a turbo-Brayton cryocooler was in the NICMOS Cooling System (NCS). The NCS has been operational on the Hubble Space Telescope for over 3.5 years without any degradation. It provides 7 W of cooling at 70 K. The scaling of the technology to higher capacities is the subject of this paper.

  10. Efficacy of triplet regimen antiemetic therapy for chemotherapy-induced nausea and vomiting (CINV) in bone and soft tissue sarcoma patients receiving highly emetogenic chemotherapy, and an efficacy comparison of single-shot palonosetron and consecutive-day granisetron for CINV in a randomized, single-blinded crossover study.

    PubMed

    Kimura, Hiroaki; Yamamoto, Norio; Shirai, Toshiharu; Nishida, Hideji; Hayashi, Katsuhiro; Tanzawa, Yoshikazu; Takeuchi, Akihiko; Igarashi, Kentaro; Inatani, Hiroyuki; Shimozaki, Shingo; Kato, Takashi; Aoki, Yu; Higuchi, Takashi; Tsuchiya, Hiroyuki

    2015-03-01

    The first aim of this study was to evaluate combination antiemetic therapy consisting of 5-HT3 receptor antagonists, neurokinin-1 receptor antagonists (NK-1RAs), and dexamethasone for multiple high emetogenic risk (HER) anticancer agents in bone and soft tissue sarcoma. The second aim was to compare the effectiveness of single-shot palonosetron and consecutive-day granisetron in a randomized, single-blinded crossover study. A single randomization method was used to assign eligible patients to the palonosetron or granisetron arm. Patients in the palonosetron arm received a palonosetron regimen during the first and third chemotherapy courses and a granisetron regimen during the second and fourth courses. All patients received NK-1RA and dexamethasone. Patients receiving the palonosetron regimen were administered 0.75 mg palonosetron on day 1, and patients receiving the granisetron regimen were administered 3 mg granisetron twice daily on days 1 through 5. All 24 patients in this study received at least 4 chemotherapy courses. A total of 96 courses of antiemetic therapy were evaluated. Overall, the complete response CR rate (no emetic episodes and no rescue medication use) was 34%, while the total control rate (a CR plus no nausea) was 7%. No significant differences were observed between single-shot palonosetron and consecutive-day granisetron. Antiemetic therapy with a 3-drug combination was not sufficient to control chemotherapy-induced nausea and vomiting (CINV) during chemotherapy with multiple HER agents for bone and soft tissue sarcoma. This study also demonstrated that consecutive-day granisetron was not inferior to single-shot palonosetron for treating CINV.

  11. Design of Three-Dimensional Multiple Slice Turbo Codes

    NASA Astrophysics Data System (ADS)

    Gnaedig, David; Boutillon, Emmanuel; Jézéquel, Michel

    2005-12-01

    This paper proposes a new approach to designing low-complexity high-speed turbo codes for very low frame error rate applications. The key idea is to adapt and optimize the technique of multiple turbo codes to obtain the required frame error rate combined with a family of turbo codes, called multiple slice turbo codes (MSTCs), which allows high throughput at low hardware complexity. The proposed coding scheme is based on a versatile three-dimensional multiple slice turbo code (3D-MSTC) using duobinary trellises. Simple deterministic interleavers are used for the sake of hardware simplicity. A new heuristic optimization method of the interleavers is described, leading to excellent performance. Moreover, by a novel asymmetric puncturing pattern, we show that convergence can be traded off against minimum distance (i.e., error floor) in order to adapt the performance of the 3D-MSTC to the requirement of the application. Based on this asymmetry of the puncturing pattern, two new adapted iterative decoding structures are proposed. Their performance and associated decoder complexities are compared to an 8-state and a 16-state duobinary 2D-MSTC. For a [InlineEquation not available: see fulltext.] information frame, the [InlineEquation not available: see fulltext.]-state trellis 3D-MSTC proposed achieves a throughput of [InlineEquation not available: see fulltext.] for an estimated area of[InlineEquation not available: see fulltext.] in a [InlineEquation not available: see fulltext.] technology. The simulation results show that the FER is below [InlineEquation not available: see fulltext.] at SNR of [InlineEquation not available: see fulltext.], which represents a gain of more than [InlineEquation not available: see fulltext.] over an [InlineEquation not available: see fulltext.]-state 2D-MSTC. The union bound gives an error floor that appears at FER below [InlineEquation not available: see fulltext.]. The performance of the proposed 3D-MSTC for low FERs outperforms the

  12. Detection of Traumatic Bone Marrow Lesions after Knee Trauma: Comparison of ADC Maps Derived from Diffusion-weighted Imaging with Standard Fat-saturated Proton Density-weighted Turbo Spin-Echo Sequences.

    PubMed

    Klengel, Alexis; Stumpp, Patrick; Klengel, Steffen; Böttger, Ina; Rönisch, Nadja; Kahn, Thomas

    2016-10-24

    Purpose To compare single-shot echo-planar diffusion-weighted imaging-derived apparent diffusion coefficient (ADC) maps with fat-saturated (FS) proton density (PD)-weighted turbo spin-echo (TSE) imaging in the detection of bone marrow lesions (BMLs) after knee trauma. Materials and Methods Institutional review board approval was obtained from Leipzig University. Written informed consent was waived. Three radiologists retrospectively re-examined 97 consecutive patients with reported knee trauma who underwent 1.5-T magnetic resonance (MR) imaging within 90 days of knee trauma. The following sequences were used: (a) sagittal T1-weighted TSE and FS PD-weighted TSE and (b) sagittal T1-weighted TSE and single-shot echo-planar diffusion-weighted imaging-derived ADC mapping. BMLs on the lateral and medial femoral condyle, lateral and medial aspect of the tibial plateau, and patella were documented. Volumetry was performed on BMLs with a thickness of at least 15 mm (major BMLs). ADC values were measured in intact bone marrow and major BMLs. A McNemar test and t tests were used as appropriate to test for significant differences between BML number and volume at an α level of .05. Results Significantly more patients showed at least one BML on ADC maps (98%, 95 of 97 patients) than on FS PD-weighted TSE images (86%, 84 of 97 patients) (P < .001). Of the affected regions detected on FS PD-weighted TSE images, 97% (170 of 175 regions) were identified consistently on ADC maps. Only 58% of the affected regions detected on ADC maps (170 of 293 regions) were identified on FS PD-weighted TSE images (P < .001). Median volume of concordant major BML was approximately two times larger on ADC maps (81 cm(3)) than on FS PD-weighted TSE images (39 cm(3)) (P < .001). The ADC values of intact bone marrow and BMLs did not overlap. Conclusion ADC maps are more sensitive than corresponding FS PD-weighted TSE images for detection of BML after knee trauma and allow detection of significantly more

  13. Spectral Characterization of a Prototype SFA Camera for Joint Visible and NIR Acquisition

    PubMed Central

    Thomas, Jean-Baptiste; Lapray, Pierre-Jean; Gouton, Pierre; Clerc, Cédric

    2016-01-01

    Multispectral acquisition improves machine vision since it permits capturing more information on object surface properties than color imaging. The concept of spectral filter arrays has been developed recently and allows multispectral single shot acquisition with a compact camera design. Due to filter manufacturing difficulties, there was, up to recently, no system available for a large span of spectrum, i.e., visible and Near Infra-Red acquisition. This article presents the achievement of a prototype of camera that captures seven visible and one near infra-red bands on the same sensor chip. A calibration is proposed to characterize the sensor, and images are captured. Data are provided as supplementary material for further analysis and simulations. This opens a new range of applications in security, robotics, automotive and medical fields. PMID:27367690

  14. 14 CFR 121.643 - Fuel supply: Nonturbine and turbo-propeller-powered airplanes: Supplemental operations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Fuel supply: Nonturbine and turbo-propeller-powered airplanes: Supplemental operations. 121.643 Section 121.643 Aeronautics and Space FEDERAL AVIATION... Flight Release Rules § 121.643 Fuel supply: Nonturbine and turbo-propeller-powered...

  15. 14 CFR 121.641 - Fuel supply: Nonturbine and turbo-propeller-powered airplanes: Flag operations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Fuel supply: Nonturbine and turbo-propeller-powered airplanes: Flag operations. 121.641 Section 121.641 Aeronautics and Space FEDERAL AVIATION... Flight Release Rules § 121.641 Fuel supply: Nonturbine and turbo-propeller-powered airplanes:...

  16. 14 CFR 121.641 - Fuel supply: Nonturbine and turbo-propeller-powered airplanes: Flag operations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Fuel supply: Nonturbine and turbo-propeller-powered airplanes: Flag operations. 121.641 Section 121.641 Aeronautics and Space FEDERAL AVIATION... Flight Release Rules § 121.641 Fuel supply: Nonturbine and turbo-propeller-powered airplanes:...

  17. 14 CFR 121.643 - Fuel supply: Nonturbine and turbo-propeller-powered airplanes: Supplemental operations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Fuel supply: Nonturbine and turbo-propeller-powered airplanes: Supplemental operations. 121.643 Section 121.643 Aeronautics and Space FEDERAL AVIATION... Flight Release Rules § 121.643 Fuel supply: Nonturbine and turbo-propeller-powered...

  18. Low Complexity Turbo Receiver for LTE Uplink with Transmitter IQ Imbalance

    NASA Astrophysics Data System (ADS)

    Liu, Rui; Ding, Lv; Gao, Xi Qi

    In this paper, we investigate two improved turbo receivers for the Long Term Evolution (LTE) uplink in the presence of transmitter (Tx) in-phase and quadrature-phase imbalance (IQI) with parameters known at eNodeB. For multiuser multiple-input multiple-output (MU-MIMO) single-carrier frequency division multiple access (SC-FDMA) systems, we derive a optimal joint linear minimum mean square error (MMSE) turbo multiuser detector (MUD) based on the mirror symmetry clusters. For the single use SC-FDMA system with Tx IQI, we derive an optimal widely linear MMSE (WLMMSE) turbo equalizer. Both receivers are implemented in the discrete frequency domain and only slightly increase the computational complexity compared to the conventional turbo receivers. Monte Carlo simulations show that the proposed receivers significantly outperform the conventional turbo receivers. The simulation results are then confirmed by the extrinsic information transfer (EXIT) chart analysis.

  19. Turbo FRMAC 2016 Version 7.1.0

    SciTech Connect

    Fulton, John; Gallagher, Linda K.; Madrid, Gregory J.; Whitener, Dustin Heath; Folz, Wesley; Herman, Joshua James; Schetnan, Richard R.; Watson, Bryan Walker; Clayton, Joe; Harms, Natalia; Gonzales, Alejandro

    2016-08-01

    The Turbo FRMAC (TF) software program is the software implementation of the science and methodologies utilized in the Federal Radiological Monitoring and Assessment Center (FRMAC). The software automates the calculations described in volumes 1 of "The Federal Manual for Assessing Environmental Data during a Radiological Emergency" (2015 version). In the event of the intentional or accidental release of radioactive material, the software is used to guide and govern the response of the Federal, State, Local, and Tribal governments. The manual, upon which the software is based, is unclassified and freely available on the Internet.

  20. Signal-processing theory for the TurboRogue receiver

    NASA Technical Reports Server (NTRS)

    Thomas, J. B.

    1995-01-01

    Signal-processing theory for the TurboRogue receiver is presented. The signal form is traced from its formation at the GPS satellite, to the receiver antenna, and then through the various stages of the receiver, including extraction of phase and delay. The analysis treats the effects of ionosphere, troposphere, signal quantization, receiver components, and system noise, covering processing in both the 'code mode' when the P code is not encrypted and in the 'P-codeless mode' when the P code is encrypted. As a possible future improvement to the current analog front end, an example of a highly digital front end is analyzed.

  1. Micro-turbo-generator design and fabrication: A preliminary study

    SciTech Connect

    Wiegele, T.G.

    1996-12-31

    The size and weight of portable electronic products are often dictated by the physical characteristics of the power supply system. The design of energy storage systems is therefore critical to market competitiveness. An alternative to energy storage is proposed in this paper which relies on a very small power generation system which converts a pressure difference in a gas into electrical power: a micro-turbo-generator. The design of the micro-turbo-generator involved combining two very different machines, a micro-generator and a micro-turbine, into a single device which could be fabricated within the constraints of current microelectronic processing techniques. Research into power generation on the micro-scale has begun to take place in the form of electromagnetic micro-motor design and fabrication. These variable reluctance machines can be transformed into power generation devices by implementing accurate rotor position sensing, high-speed current switching and a means for inducing rotor motion. This leads to the implementation of a switched reluctance generator, which is well-understood on the macro-scale but has not been attempted on the micro-scale. The most significant hurdle facing researchers is the task of coupling a prime mover, such as a micro-turbine, to the rotor of a power generation device efficiently and effectively while maintaining relative simplicity in the fabrication procedures. The design presented here offers a potential solution to this problem.

  2. Life and Reliability Characteristics of TurboBrayton Coolers

    NASA Technical Reports Server (NTRS)

    Breedlove, Jeff J.; Zagarola, Mark; Nellis, Greg; Dolan, Frank; Swift, Walt; Gibbon, Judith; Obenschain, Arthur F. (Technical Monitor)

    2000-01-01

    Wear and internal contaminants are two of the primary factors that influence reliable, long-life operation of turbo-Brayton cryocoolers. This paper describes tests that have been conducted and methods that have been developed for turbo-Brayton components and systems to assure reliable operation. The turbomachines used in these coolers employ self-acting gas bearings to support the miniature high-speed shafts, thus providing vibration-free operation. Because the bearings are self-acting, rubbing contact occurs during initial start-up and shutdown of the machines. Bearings and shafts are designed to endure multiple stop/start cycles without producing particles or surface features that would impair the proper operation of the machines. Test results are presented for a variety of turbomachines used in these systems. The tests document extended operating life and start/stop cycling behavior for machines over a range of time and temperature scales. Contaminants such as moisture and other residual gas impurities can be a source of degraded operation if they freeze out in sufficient quantities to block flow passages or if they mechanically affect the operation of the machines. A post-fabrication bakeout procedure has been successfully used to reduce residual internal contamination to acceptable levels in a closed cycle system. The process was developed during space qualification tests on the NICMOS cryocooler. Moisture levels were sampled over a six-month time interval confirming the effectiveness of the technique. A description of the bakeout procedure is presented.

  3. Advanced Developments for Low Temperature Turbo-Brayton Cryocoolers

    NASA Technical Reports Server (NTRS)

    Nellis, G. F.; McCormick, J. A.; Sixsmith, H.; Zagarola, M. V.; Swift, W. L.; Gibbon, J. A.; Reilly, J. P.; Obenschain, Arthur F. (Technical Monitor)

    2000-01-01

    Turbo-Brayton cryocooler technology that has been space qualified and demonstrated on the NICMOS cryocooler is being adapted for applications with lower cooling loads at lower telqoeratures. The applications include sensor cooling for space platforms and telescopes at temperatures between 4 K and 35 K, where long life and reliable, vibration-free operation are important. This paper presents recent advances in the miniaturization of components that are critical to these systems. Key issues addressed in adapting the NICMOS cryocooler technology to lower temperatures involve reducing parasitic losses when scaling to smaller size machines. Recent advances include the successful design and testing of a small, permanent magnet driven compressor that operates at up to 10,000 rev/sec and the successful demonstration of self acting gas bearings supporting a I mm. diameter shaft. The compressor is important for cryocoolers with input powers between 50 W and 100 W. The miniature shaft and bearing system has applications in compressors and turbines at temperatures from 300 K to 6 K. These two technology milestones are fundamental to achieving exceptional thermodynamic performance from the turboBrayton system in low temperature systems. The paper discusses the development of these components and test results, and presents the implications of their performance on cryocooler systems.

  4. Modifying the Turbo Decoder for DVC over Wireless Channels

    NASA Astrophysics Data System (ADS)

    Weerakkody, Rajitha; Fernando, Anil; M. Kondoz, Ahmet

    Distributed Video Coding (DVC) is an emerging video coding approach, particularly attractive due to its flexibility to implement low complex encoders. This feature could be very effectively utilized in a number of video sensor based application scenarios. However, DVC is still in the process of development and currently available codec implementations are based on a number of hypothetical models and assumptions. In DVC, the effects of noise and fading on the compressed payload (parity bit stream) in real video communications and the resultant modified channel model scenario have not been discussed in literature. In this paper, a solution to the above problem in turbo coding based DVC is discussed incorporating a novel dual channel model for the maximum a-posteriori (MAP) algorithm for turbo decoding. The simulations for AWGN and wireless channels at different group of picture (GOP) sizes show that the proposed algorithm improves the rate distortion performance compared to the existing decoding algorithm. It also outperforms the H.264/AVC I-P-I-P codec (v10.1/baseline profile); particularly at low Signal to Noise Ratio (SNR) levels of the channel, thus enabling DVC as a viable and efficient option for video communications.

  5. Application of TURBO-AE to Flutter Prediction: Aeroelastic Code Development

    NASA Technical Reports Server (NTRS)

    Hoyniak, Daniel; Simons, Todd A.; Stefko, George (Technical Monitor)

    2001-01-01

    The TURBO-AE program has been evaluated by comparing the obtained results to cascade rig data and to prediction made from various in-house programs. A high-speed fan cascade, a turbine cascade, a turbine cascade and a fan geometry that shower flutter in torsion mode were analyzed. The steady predictions for the high-speed fan cascade showed the TURBO-AE predictions to match in-house codes. However, the predictions did not match the measured blade surface data. Other researchers also reported similar disagreement with these data set. Unsteady runs for the fan configuration were not successful using TURBO-AE .

  6. Design and Development of a 200-kW Turbo-Electric Distributed Propulsion Testbed

    NASA Technical Reports Server (NTRS)

    Papathakis, Kurt V.

    2017-01-01

    There a few NASA funded electric and hybrid electric projects from different NASA Centers, including the NASA Armstrong Flight Research Center (AFRC) (Edwards, California). Each project identifies a specific technology gap that is currently inhibiting the growth and proliferation of relevant technologies in commercial aviation. This paper describes the design and development of a turbo-electric distributed propulsion (TeDP) hardware-in-the-loop (HIL) simulation bench, which is a test bed for discovering turbo-electric control, distributed electric control, power management control, and integration competencies while providing risk mitigation for future turbo-electric flying demonstrators.

  7. Study on Performance and Internal Flow Condition of Mini Turbo-Pump

    NASA Astrophysics Data System (ADS)

    Shigemitsu, Toru; Fukutomi, Junichiro; Nasada, Ryoichi

    2010-06-01

    Mini turbo-pumps which have a diameter smaller than 100mm are utilized in many fields; automobile radiator pump, artificial heart pump, cooling pump for electric devices, washing machine pump and so on. And the needs for the mini turbo-pumps would become larger with the increase of the application of it for electrical machines. It is desirable that the mini turbo-pump design is as simple as possible due to the limitation of the precision for manufacture. But the design method for the mini turbo-pump is not established because the internal flow condition for these small-sized fluid machineries is not clarified and conventional theory is not conductive for small-sized pumps because of the low Reynolds number and the size effects. Therefore, we started the research of the mini turbo-pump for the purpose of development of high performance mini turbo-pump with simple structure. As a first step of this research, mini turbo-pump with the 46mm rotor diameter was designed based on the conventional design method in order to clarify the problems for the application of conventional method for mini turbo-pump in details. The three dimensional steady numerical flow analysis was conducted with the commercial code (Fluent6.3). The numerical flow analysis was also performed under the condition with and without a tip clearance because the tip clearance influence on the performance and internal flow condition is extremely large for mini turbo-pumps. It was clarified from the numerical results that head of the mini turbo-pump at the designed point without the tip clearance satisfied the designed value head H = 1.2m and the efficiency is about η = 60% which is acceptable value for the centrifugal pump. On the other hand, head and efficiency decreased drastically with the increase of the tip clearance. The flow condition near the tip region was influenced by the leakage flow from the blade tip. And it is observed by the results of the total pressure distributions that the total

  8. Super-resolution reconstruction to increase the spatial resolution of diffusion weighted images from orthogonal anisotropic acquisitions

    PubMed Central

    Scherrer, Benoit; Gholipour, Ali; Warfield, Simon K.

    2012-01-01

    Diffusion-weighted imaging (DWI) enables non-invasive investigation and characterization of the white matter but suffers from a relatively poor spatial resolution. Increasing the spatial resolution in DWI is challenging with a single-shot EPI acquisition due to the decreased signal-to-noise ratio and T2* relaxation effect amplified with increased echo time. In this work we propose a super-resolution reconstruction (SRR) technique based on the acquisition of multiple anisotropic orthogonal DWI scans. DWI scans acquired in different planes are not typically closely aligned due to the geometric distortion introduced by magnetic susceptibility differences in each phase-encoding direction. We compensate each scan for geometric distortion by acquisition of a dual echo gradient echo field map, providing an estimate of the field inhomogeneity. We address the problem of patient motion by aligning the volumes in both space and q-space. The SRR is formulated as a maximum a posteriori problem. It relies on a volume acquisition model which describes how the acquired scans are observations of an unknown high-resolution image which we aim to recover. Our model enables the introduction of image priors that exploit spatial homogeneity and enables regularized solutions. We detail our SRR optimization procedure and report experiments including numerical simulations, synthetic SRR and real world SRR. In particular, we demonstrate that combining distortion compensation and SRR provides better results than acquisition of a single isotropic scan for the same acquisition duration time. Importantly, SRR enables DWI with resolution beyond the scanner hardware limitations. This work provides the first evidence that SRR, which employs conventional single shot EPI techniques, enables resolution enhancement in DWI, and may dramatically impact the role of DWI in both neuroscience and clinical applications. PMID:22770597

  9. Coupled Receiver/Decoders for Low-Rate Turbo Codes

    NASA Technical Reports Server (NTRS)

    Hamkins, Jon; Divsalar, Dariush

    2005-01-01

    been proposed for receiving weak single- channel phase-modulated radio signals bearing low-rate-turbo-coded binary data. Originally intended for use in receiving telemetry signals from distant spacecraft, the proposed receiver/ decoders may also provide enhanced reception in mobile radiotelephone systems. A radio signal of the type to which the proposal applies comprises a residual carrier signal and a phase-modulated data signal. The residual carrier signal is needed as a phase reference for demodulation as a prerequisite to decoding. Low-rate turbo codes afford high coding gains and thereby enable the extraction of data from arriving radio signals that might otherwise be too weak. In the case of a conventional receiver, if the signal-to-noise ratio (specifically, the symbol energy to one-sided noise power spectral density) of the arriving signal is below approximately 0 dB, then there may not be enough energy per symbol to enable the receiver to recover properly the carrier phase. One could solve the problem at the transmitter by diverting some power from the data signal to the residual carrier. A better solution . a coupled receiver/decoder according to the proposal . could reduce the needed amount of residual carrier power. In all that follows, it is to be understood that all processing would be digital and the incoming signals to be processed would be, more precisely, outputs of analog-to-digital converters that preprocess the residual carrier and data signals at a rate of multiple samples per symbol. The upper part of the figure depicts a conventional receiving system, in which the receiver and decoder are uncoupled, and which is also called a non-data-aided system because output data from the decoder are not used in the receiver to aid in recovering the carrier phase. The receiver tracks the carrier phase from the residual carrier signal and uses the carrier phase to wipe phase noise off the data signal. The receiver typically includes a phase-locked loop

  10. Design modification in rotor blade of turbo molecular pump

    NASA Astrophysics Data System (ADS)

    Iqbal, Munawar; Wasy, Abdul; Batani, Dimitri; Rashid, Haris; Lodhi, M. A. K.

    2012-06-01

    Performance of a Turbo Molecular Pump (TMP) is strongly related to the frequency of the rotor. As rpm increases deflection in the rotor blades starts to occur. Therefore, quality of material and blade design has been modified in order to obtain stable performance at higher speed. To reduce the deformation, stiffer material and change in blade design have been calculated. Significant improvement has been achieved in modeling the blade design using CATIA software. The analysis has been performed by ANSYS workbench. It is shown that the modification in the blade design of TMP rotor has reduced the structural deformation up to 66 percent of the deformation produced in the original blade design under the same conditions. Modified design achieved additional 23 percent rpm which increased TMP's efficiency.

  11. Turbo FISH: A Method for Rapid Single Molecule RNA FISH

    PubMed Central

    Shaffer, Sydney M.; Wu, Min-Tzu; Levesque, Marshall J.; Raj, Arjun

    2013-01-01

    Advances in RNA fluorescence in situ hybridization (RNA FISH) have allowed practitioners to detect individual RNA molecules in single cells via fluorescence microscopy, enabling highly accurate and sensitive quantification of gene expression. However, current methods typically employ hybridization times on the order of 2–16 hours, limiting its potential in applications like rapid diagnostics. We present here a set of conditions for RNA FISH (dubbed Turbo RNA FISH) that allow us to make accurate measurements with no more than 5 minutes of hybridization time and 3 minutes of washing, and show that hybridization times can go as low as 30 seconds while still producing quantifiable images. We further show that rapid hybridization is compatible with our recently developed iceFISH and SNP FISH variants of RNA FISH that enable chromosome and single base discrimination, respectively. Our method is simple and cost effective, and has the potential to dramatically increase the throughput and realm of applicability of RNA FISH. PMID:24066168

  12. Developments in TurboBrayton Technology for Low Temperature Applications

    NASA Technical Reports Server (NTRS)

    Swift, W. L.; Zagarola, M. V.; Nellis, G. F.; McCormick, J. A.; Gibbon, Judy

    1999-01-01

    A single stage reverse Brayton cryocooler using miniature high-speed turbomachines recently completed a successful space shuttle test flight demonstrating its capabilities for use in cooling the Near Infrared Camera and Multi-Object Spectrometer (NICMOS) on the Hubble Space Telescope (HST). The NICMOS CryoCooler (NCC) is designed for a cooling load of about 8 W at 65 K, and comprises a closed loop cryocooler coupled to an independent cryogenic circulating loop. Future space applications involve instruments that will require 5 mW to 200 mW of cooling at temperatures between 4 K and 10 K. This paper discusses the extension of Turbo-Brayton technology to meet these requirements.

  13. Deep Space Network turbo decoder infusion: enhanced performance and lower decoder complexity

    NASA Technical Reports Server (NTRS)

    Pollara, F.; Andrews, K.

    2002-01-01

    This article describes the effort to deploy turbo decoders in the Deep Space Network to service missions launching in 2003 and later, and the implications of these new capabilities for the design of future missions.

  14. Solution of turbo codes' error floor in a radio-optical communication environment

    NASA Astrophysics Data System (ADS)

    Niu, Xueyu; Qiao, Huijie; Wen, Chuanhua

    2005-11-01

    Turbo codes are used to guarantee the performance in the power-limited radio-optical communication system, but the traditional parallel structure is difficult to overcome the 'error floor'. In this paper, a hybrid structure is studied, it is the combination of the parallel structure and the serial structure. Turbo codes with the hybrid structure can improve the system performance validly, but the complication is the cost. Through the theoretic analyses and computer simulation, the hybrid structure is proved to be valid.

  15. Optimization of sparse phase encodings for variable repetition-delay turbo-spin echo (TSE) T1 measurements for preclinical applications

    NASA Astrophysics Data System (ADS)

    Lee, DongKyu; Han, Sohyun; Cho, HyungJoon

    2017-01-01

    A variable repetition-delay (TR) spin echo sequence with repeated refocusing pulses, i.e., a variable TR turbo-spin echo (TSE), provides an attractive means of acquiring an accurate T1 map information that is free from gradient echo based artifacts such as magnetic field inhomogeneities particularly for ultra-high field (at 7T and above) preclinical applications. However, the applicability of multi-slice TSE sequences is often limited by signal distortion from T2 relaxation due to echo-train acquisitions for short T2 tissues, inter-slice cross talks and magnetization transfer (MT) from repetitive slice-selective 180° pulse, and extended scan times with multiple TR excitations. These TSE shortcomings are difficult to remedy for preclinical applications, where small sizes of target organs usually limit the slice-gap control with restricted parallel imaging capabilities. In this study, compressed-sensing-assisted turbo-spin echo (CS-TSE) acquisitions for variable TR T1 measurements at 7T preclinical scanner were implemented to reduce the echo-trains by sparse phase encodings. Following the sparse signal simulation and sampling scheme optimization, the measured T1 values from CS-TSE and TSE were compared for phantoms, ex vivo, and in vivo subjects. The phantom T1 values from CS-TSE and TSE were identical to those from the inversion recovery spin echo. For both ex vivo and in vivo multi-slice T1 mapping, the shortened echo-trains of CS-TSE relieved the T2 relaxation, reduced the inter-slice interferences of multi-slice acquisition, and made room for additional slice encodings while maintaining a shorter scan time than the conventional TSE at the expense of local image smoothness from CS regularizations.

  16. Compact and High Thrust Air Turbo Ram Engine

    NASA Astrophysics Data System (ADS)

    Hasegawa, Hiroaki; Kitahara, Kazuki; Inukai, Yasuo

    The Air Turbo Ramjet (ATR) is a combined cycle engine which performs like a turbojet engine at subsonic speeds and a ramjet at supersonic speeds and therefore the ATR is an attractive propulsion system for the wide operation range (e.g. Mach 0 to Mach 4). The ATR can provide a higher specific impulse than a solid fuel rocket engine and a higher thrust per frontal area than a turbojet engine. The major ATR components are the inlet, fan (compressor), turbine, gas generator, combustor and exhaust nozzle. In the ATR, the turbine drive gas is generated by a decomposed liquid or solid fuel gas generator. In order to carry heavier payloads and to attain shorter flight time, the compact and high thrust engine is required. In this study, the ram combustor with the double-staged flameholders and the fan with tandem blade were introduced to shorten the engine length and to increase the fan pressure ratio, respectively. Furthermore, the engine testing was carried out on sea level static condition to confirm the engine component integration technologies for the ATR propulsion system.

  17. Information transmission using UEP turbo codes in wireless sensor networks

    NASA Astrophysics Data System (ADS)

    Zhou, Zude; Xu, Chao

    2005-11-01

    Wireless sensing is prevalent quickly in these years, and it has many advantages, such as fewer catastrophic failures, conservation of natural resources, improved emergency response, etc. Wireless sensors can be deployed in extremely hostile environment. Since the wireless sensors are energy constrained, many researches have been in progress to solve these problems. In this paper, we proposed a joint source-channel coding scheme to solve energy efficiency of wireless sensors. Firstly, we decomposition information in wavelet domain, then compress it by using multi-scale embedded zerotree wavelet algorithm, and generate a bit stream that can be decompressed in a scalable bit rate. Then, we transmit the bit stream after encoding them with unequal error protection turbo codes to achieve error robust transmission. We transmit multiple bit streams according to some energy strategy, and redundancies to base stations are reduced by only transmitting coarse scale information. Due to the scalability of multi-scale EZW, we can adopt diversified bit rate strategy to save energy of battery powered sensors.

  18. Weight distributions for turbo codes using random and nonrandom permutations

    NASA Technical Reports Server (NTRS)

    Dolinar, S.; Divsalar, D.

    1995-01-01

    This article takes a preliminary look at the weight distributions achievable for turbo codes using random, nonrandom, and semirandom permutations. Due to the recursiveness of the encoders, it is important to distinguish between self-terminating and non-self-terminating input sequences. The non-self-terminating sequences have little effect on decoder performance, because they accumulate high encoded weight until they are artificially terminated at the end of the block. From probabilistic arguments based on selecting the permutations randomly, it is concluded that the self-terminating weight-2 data sequences are the most important consideration in the design of constituent codes; higher-weight self-terminating sequences have successively decreasing importance. Also, increasing the number of codes and, correspondingly, the number of permutations makes it more and more likely that the bad input sequences will be broken up by one or more of the permuters. It is possible to design nonrandom permutations that ensure that the minimum distance due to weight-2 input sequences grows roughly as the square root of (2N), where N is the block length. However, these nonrandom permutations amplify the bad effects of higher-weight inputs, and as a result they are inferior in performance to randomly selected permutations. But there are 'semirandom' permutations that perform nearly as well as the designed nonrandom permutations with respect to weight-2 input sequences and are not as susceptible to being foiled by higher-weight inputs.

  19. Performance characteristics of a turbo expander substituted for expansion valve on air-conditioner

    SciTech Connect

    Cho, Soo-Yong; Cho, Chong-Hyun; Kim, Chaesil

    2008-09-15

    An experimental study is conducted on a small turbo expander which could be applied to the expansion process in place of expansion valves in refrigerator or air-conditioner to improve the cycle efficiency by recovering energy from the throttling process. The operating gas is HFC134a and the maximum cooling capacity of experiment apparatus is 32.7 kW. Four different turbo expanders are tested to find the performance characteristics of the turbo expander when they operate at a low partial admission rate. The partial admission rate is 1.70% or 2.37, and expanders are operated in the supersonic flow. In the experiment, pressure and temperature are measured at 10 different locations in the experimental apparatus. In addition to these measurements, output power at the turbo expander is measured through a generator installed on a rotor shaft with the rotational speed. Performance data of the turbo expander are obtained at many part load operations by adjusting the output power of the generator. A maximum of 15.8% total-to-static efficiency is obtained when the pressure ratio and the partial admission ratio are 2.37 and 1.70%, respectively. Experimental results show that the optimal velocity ratio decreases when the pressure ratio is decreased, and peak efficiencies, which are obtained at locally maximized efficiency depending on the operating condition, vary linearly against the subcooling temperature or the pressure ratio. (author)

  20. Robust wireless video transmission employing byte-aligned variable-length turbo code

    NASA Astrophysics Data System (ADS)

    Lee, ChangWoo; Kim, JongWon

    2002-01-01

    Video transmission over the multi-path fading wireless channel has to overcome the inherent vulnerability of compressed video to the channel errors. To effectively prevent the corruption of video stream and its propagation in spatial and temporal domain, proactive error controls are widely being deployed. Among possible candidates, turbo code is known to exhibit superior error correction performance over fading channel. Ordinary turbo codes, however, are not suitable to support the variable-size segment of the video stream. A version of turbo code, byte-aligned variable-length turbo code, is thus proposed and applied for the robust video transmission system. Protection performance of the proposed turbo code is evaluated by applying it to GOB-based variable-size ITU-T H.263+ video packets, where the protection level is controlled based on the joint source-channel criteria. The resulting performance comparison with the conventional RCPC code clearly demonstrates the possibility of the proposed approach for the time-varying correlated Rayleigh-fading channel.

  1. The measurement of thermodynamic performance in cryogenic two-phase turbo-expander

    NASA Astrophysics Data System (ADS)

    Niu, Lu; Hou, Yu; Sun, Wan; Chen, Shuangtao

    2015-09-01

    Liquid fraction measurement in cryogenic two-phase flow is a complex issue, especially for an industrial cryogenic system. In this paper, a simple thermal method is proposed for measuring the liquid fraction in cryogenic two-phase turbo-expander by an electric heating unit in experimental study. The liquid fraction of the cryogenic two-phase flow is determined through the heat balance built at the outlet of the turbo-expander (inlet of heating unit) and the outlet of the heating unit. Liquid fractions from 1.16% to 5.02% are obtained from five two-phase expansion cases. Under the same turbo-expander inlet pressure and rotating speed, five superheated expansion cases are tested to evaluate the wetness loss in two-phase expansion. The results show that the proposed method is successful in measuring the liquid fraction of cryogenic two-phase expansion for turbo-expander in an industrial air separation plant. The experimental isentropic efficiency ratio and the tested Baumann factor decrease with the increasing mean wetness. Based on prediction of Baumann rule, the cryogenic turbo-expander with low liquid fraction in two-phase expansion cases suffers from more severe wetness loss than that with the higher liquid fraction.

  2. The TurboLAN project. Phase 1: Protocol choices for high speed local area networks. Phase 2: TurboLAN Intelligent Network Adapter Card, (TINAC) architecture

    NASA Technical Reports Server (NTRS)

    Alkhatib, Hasan S.

    1991-01-01

    The hardware and the software architecture of the TurboLAN Intelligent Network Adapter Card (TINAC) are described. A high level as well as detailed treatment of the workings of various components of the TINAC are presented. The TINAC is divided into the following four major functional units: (1) the network access unit (NAU); (2) the buffer management unit; (3) the host interface unit; and (4) the node processor unit.

  3. Implementation of single-shot ellipsometry on gas gun experiments

    NASA Astrophysics Data System (ADS)

    Grant, Sean; Ao, Tommy; Bernstein, Aaron; Ditmire, Todd; Dolan, Dan; Lin, Jung-Fu; Seagle, Chris; Davis, Jean-Paul

    2017-01-01

    We have built and implemented a time-resolved ellipsometry diagnostic for dynamic material properties experiments at Sandia National Laboratories. This diagnostic measures the complex dielectric value of a sample experiencing dynamic compression, with a time resolution of a few nanoseconds. We show and discuss the dynamic ellipsometry measurements taken from shock loading experiments on a gas gun. This work is relevant to geophysical materials at high pressure-temperature conditions.

  4. Single shot thermometry using laser induced thermal grating

    NASA Astrophysics Data System (ADS)

    Qu, Pubo; Guan, Xiaowei; Zhang, Zhenrong; Wang, Sheng; Li, Guohua; Ye, Jingfeng; Hu, Zhiyun

    2015-05-01

    With the concern of environmental protection and reducing the fossil fuel consumption, combustion processes need to be more efficient and less contaminable. Therefore, the ability to obtain important thermophysical parameters is crucial to combustion research and combustor design. Traditional surveying techniques were difficult to apply in a confined space, especially the physically intrusions of detectors can alter the combustion processes. Laser-based diagnostic techniques, like CARS, SVRS, PLIF and TDLAS, allow the in situ, non-intrusive, spatially and temporally resolved measurements of combustion parameters in hostile environments. We report here a new non-intrusive optical diagnostic technique, based on laser-induced thermal grating. Thermal gratings generated in NO2/N2 binary mixtures, arise from the nonlinear interaction between the medium and the light radiation from the interference of two pulsed, frequency-doubled Nd:YAG lasers (532 nm). This leads to the formation of a dynamic grating through the resonant absorption and the subsequent collisional relaxation. By the temporally resolved detection of a continuous wave, frequency-doubled Nd:YVO4 probe laser beam (671 nm) diffracted by LITG. The temporal behavior of the signal is a function of the local temperature and other properties of gas, various parameters of the target gas can be extracted by analyzing the signal. The accurate singleshot temperature measurements were carried out at different test conditions using a stainless steel pressurized cell, data averaged on 100 laser shots were compared with simultaneously recorded thermocouple data, and the results were consistent with each other. The LITG signal is shown to grow with increasing the gas pressure and is spatially coherent, which makes the LITG thermometry technique a promising candidate in high pressure environments.

  5. Single-shot Laser-assisted Nanofabrication of Plasmonic Nanorings

    NASA Astrophysics Data System (ADS)

    Nepomnyashchii, A. V.; Kuchmizhak, A. A.; Gurbatov, S. O.; Vitrik, O. B.; Kulchin, Yu. N.

    Simple high-performing two-step technique for fabrication different functional plasmonic nanostructures including nanorods, separated and crossed nanorings, as well as more complex hybrid structures on both glass and silicon substrates was proposed. In this technique the noble metal film covering bulk glass or silicon substrates is irradiated by single tightly focused nanosecond laser pulse followed by slow polishing of the fabricated nanostructures by accelerated argon ion (Ar+) beam. Nanosecond laser pulse locally modifies its initial thickness of metal film through the initiation of ultrafast melting and subsequent hydrodynamic processes, while the following Ar+ polishing reveals only the features of its topography - plasmonic structures on the glass/Si substrate. We demonstrate that both the type and lateral size of the resulting functional plasmonic nanostructure are determined by the pulse energy, metal film thickness as well as the optical spot size, while subsequent Ar+ polishing allows varying the height of the resulting nanostructures. The proposed simple two-step high-throughput technique represents the next step towards direct lased-induced fabrication of complex functional plasmonic nanostructures and is well-suited for both large-scale fabrication of ordered arrays comprising hundreds of nanoelements and single nanostructure at a given point on the sample surface.

  6. Diamond machining of a single shot ellipsoidal focusing plasma mirror

    NASA Astrophysics Data System (ADS)

    Bourgenot, C.; Crosby, D. N.; Robertson, D. J.

    2016-11-01

    Plasma mirrors have become an important tool in high power laser physics due to their ability to suppress laser pre-pulses and amplified spontaneous emission allowing a cleaner and sharper rising edge pulse to be focused onto a target. A PMMA ellipsoidal plasma mirror used to increase the peak intensity of a high power laser pulses before it reaches the target is presented. The ellipse has been designed to increase by a factor 3, between input and output, the F-number of the beam, inducing in theory a factor 9 gain in peak intensity. Diamond machining, which is a technique capable of producing sub-micron accuracy on steep, freeform surfaces, is an ideal process for manufacturing these types of mirrors. In this paper, we discuss the diamond machining requirements to manufacture such near diffraction limited high numerical aperture mirrors.

  7. Fault diagnostics for turbo-shaft engine sensors based on a simplified on-board model.

    PubMed

    Lu, Feng; Huang, Jinquan; Xing, Yaodong

    2012-01-01

    Combining a simplified on-board turbo-shaft model with sensor fault diagnostic logic, a model-based sensor fault diagnosis method is proposed. The existing fault diagnosis method for turbo-shaft engine key sensors is mainly based on a double redundancies technique, and this can't be satisfied in some occasions as lack of judgment. The simplified on-board model provides the analytical third channel against which the dual channel measurements are compared, while the hardware redundancy will increase the structure complexity and weight. The simplified turbo-shaft model contains the gas generator model and the power turbine model with loads, this is built up via dynamic parameters method. Sensor fault detection, diagnosis (FDD) logic is designed, and two types of sensor failures, such as the step faults and the drift faults, are simulated. When the discrepancy among the triplex channels exceeds a tolerance level, the fault diagnosis logic determines the cause of the difference. Through this approach, the sensor fault diagnosis system achieves the objectives of anomaly detection, sensor fault diagnosis and redundancy recovery. Finally, experiments on this method are carried out on a turbo-shaft engine, and two types of faults under different channel combinations are presented. The experimental results show that the proposed method for sensor fault diagnostics is efficient.

  8. Imaging of Heterogeneous Materials with a Turbo Spin Echo Single-Point Imaging Technique

    NASA Astrophysics Data System (ADS)

    Beyea, Steven D.; Balcom, Bruce J.; Mastikhin, Igor V.; Bremner, Theodore W.; Armstrong, Robin L.; Grattan-Bellew, Patrick E.

    2000-06-01

    A magnetic resonance imaging method is presented for imaging of heterogeneous broad linewidth materials. This method allows for distortionless relaxation weighted imaging by obtaining multiple phase encoded k-space data points with each RF excitation pulse train. The use of this method, turbo spin echo single-point imaging-(turboSPI), leads to decreased imaging times compared to traditional constant-time imaging techniques, as well as the ability to introduce spin-spin relaxation contrast through the use of longer effective echo times. Imaging times in turboSPI are further decreased through the use of low flip angle steady-state excitation. Two-dimensional images of paramagnetic doped agarose phantoms were obtained, demonstrating the contrast and resolution characteristics of the sequence, and a method for both amplitude and phase deconvolution was demonstrated for use in high-resolution turboSPI imaging. Three-dimensional images of a partially water-saturated porous volcanic aggregate (T2L ≈ 200 ms, Δν1/2 ≈ 2500 Hz) contained in a hardened white Portland cement matrix (T2L ≈ 0.5 ms, Δν1/2 ≈ 2500 Hz) and a water-saturated quartz sand (T2 ≈ 300 ms, T2* ≈ 800 μs) are shown.

  9. Fault Diagnostics for Turbo-Shaft Engine Sensors Based on a Simplified On-Board Model

    PubMed Central

    Lu, Feng; Huang, Jinquan; Xing, Yaodong

    2012-01-01

    Combining a simplified on-board turbo-shaft model with sensor fault diagnostic logic, a model-based sensor fault diagnosis method is proposed. The existing fault diagnosis method for turbo-shaft engine key sensors is mainly based on a double redundancies technique, and this can't be satisfied in some occasions as lack of judgment. The simplified on-board model provides the analytical third channel against which the dual channel measurements are compared, while the hardware redundancy will increase the structure complexity and weight. The simplified turbo-shaft model contains the gas generator model and the power turbine model with loads, this is built up via dynamic parameters method. Sensor fault detection, diagnosis (FDD) logic is designed, and two types of sensor failures, such as the step faults and the drift faults, are simulated. When the discrepancy among the triplex channels exceeds a tolerance level, the fault diagnosis logic determines the cause of the difference. Through this approach, the sensor fault diagnosis system achieves the objectives of anomaly detection, sensor fault diagnosis and redundancy recovery. Finally, experiments on this method are carried out on a turbo-shaft engine, and two types of faults under different channel combinations are presented. The experimental results show that the proposed method for sensor fault diagnostics is efficient. PMID:23112645

  10. Test results of the air turbo ramjet for a future space plane

    NASA Astrophysics Data System (ADS)

    Tanatsugu, Nobuhiro; Naruo, Yoshihiro; Rokutanda, Itaru

    The Institute of Space and Astronautical Science (ISAS) has been engaged in the development study on the Air Turbo Ramjet (ATR) engine since 1986 in cooperation with the Ishikawajima Harima Heavy Industries Co. Ltd (IHI). The ATR is one of the most preferable candidates for the propulsion system of a future space plane. Our ATR engine is a combined cycle air breathing propulsion system which consists of the turbojet and the fan boosted ramjet using the liquid hydrogen as a fuel. This engine system was named "ATREX" after employing the expander cycle. The ATREX is energized by thermal energy extracted regeneratively in both the pre-cooler installed in the air intake and the heat exchanger in combustion chamber. The ATREX works in the flight condition from sea level static up to Mach 6 at 35 km altitude. The ATREX employs the tip turbine configuration for compactness of turbo machinery. We are assessing the feasibility of the ATREX system by the sea level static tests using the 1/4- scale model (ATREX-500) with a fan inlet diameter of 300 mm and overall length of 2120 mm. In 1990, the ATREX-500 engine was tested in a sea level static condition to verify the performance characteristics of the turbo machinery and the combustor. In September of 1991, the heat exchanger was installed in the combustion chamber and tested independently from the turbo system. In November of 1991, the heat exchanger was coupled with the turbo system and tested to verify the overall system of the ATREX. In this paper are presented the test results of the ATREX-500 engine tested in the sea level static condition.

  11. Isothermal thermogravimetric data acquisition analysis system

    NASA Technical Reports Server (NTRS)

    Cooper, Kenneth, Jr.

    1991-01-01

    The description of an Isothermal Thermogravimetric Analysis (TGA) Data Acquisition System is presented. The system consists of software and hardware to perform a wide variety of TGA experiments. The software is written in ANSI C using Borland's Turbo C++. The hardware consists of a 486/25 MHz machine with a Capital Equipment Corp. IEEE488 interface card. The interface is to a Hewlett Packard 3497A data acquisition system using two analog input cards and a digital actuator card. The system provides for 16 TGA rigs with weight and temperature measurements from each rig. Data collection is conducted in three phases. Acquisition is done at a rapid rate during initial startup, at a slower rate during extended data collection periods, and finally at a fast rate during shutdown. Parameters controlling the rate and duration of each phase are user programmable. Furnace control (raising and lowering) is also programmable. Provision is made for automatic restart in the event of power failure or other abnormal terminations. Initial trial runs were conducted to show system stability.

  12. Pico-coulomb charge measured at BELLA to percent-level precision using a Turbo-ICT

    NASA Astrophysics Data System (ADS)

    Nakamura, K.; Mittelberger, D. E.; Gonsalves, A. J.; Daniels, J.; Mao, H.-S.; Stulle, F.; Bergoz, J.; Leemans, W. P.

    2016-03-01

    Precise diagnostics of picocoulomb level particle bunches produced by laser plasma accelerators (LPAs) can be a significant challenge. Without proper care, the small signals associated with such bunches can be dominated by a background generated by laser, target, laser-plasma interaction and particle induced radiation. In this paper, we report on first charge measurements using the newly developed Turbo-ICT for LPAs. We outline the Turbo-ICT working principle, which allows precise sub-picocoulomb measurements even in the presence of significant background signals. A comparison of the Turbo-ICT, a conventional integrating current transformer (ICT) and a scintillating screen (Lanex) was carried out at the Berkeley Lab Laser Accelerator. Results show that the Turbo-ICT can measure sub-picocoulomb charge accurately and has significantly improved noise immunity compared to the ICT.

  13. Mergers + acquisitions.

    PubMed

    Hoppszallern, Suzanna

    2002-05-01

    The hospital sector in 2001 led the health care field in mergers and acquisitions. Most deals involved a network augmenting its presence within a specific region or in a market adjacent to its primary service area. Analysts expect M&A activity to increase in 2002.

  14. Acquisition strategies

    SciTech Connect

    Zimmer, M.J.; Lynch, P.W. )

    1993-11-01

    Acquiring projects takes careful planning, research and consideration. Picking the right opportunities and avoiding the pitfalls will lead to a more valuable portfolio. This article describes the steps to take in evaluating an acquisition and what items need to be considered in an evaluation.

  15. The effect of blade outlet angle on performance and internal flow condition of mini turbo-pump

    NASA Astrophysics Data System (ADS)

    Shigemitsu, T.; Fukutomi, J.; Nasada, R.; Kaji, K.

    2011-03-01

    Mini turbo-pumps having a diameter smaller than 100mm are employed in many fields; automobile radiator pump, ventricular assist pump, cooling pump for electric devices, washing machine pump and so on. Further, the needs for mini turbo-pumps would become larger with the increase of the application of it for electrical machines. It is desirable that the mini turbo-pump design is as simple as possible due to restriction to make precise manufactures. But the design method for the mini turbo-pump is not established because the internal flow condition for these small-sized fluid machineries is not clarified and conventional theory is not conductive for small-sized pumps. Three types of rotors with different outlet angles are prepared for an experiment and a numerical analysis. The performance tests are conducted with these rotors in order to investigate the effect of the blade outlet angle on performance and internal flow condition of mini turbo-pumps. It is clarified from the experimental results that head of the mini turbo-pump increases and maximum efficiency flow rate shifts to larger flow rate according to the increase of the blade outlet angle, however the maximum efficiency decreases with the increase of it. In the present paper, the performance of the mini turbo-pump is shown and the internal flow conditions are clarified with the results of the experiment and the numerical flow analysis. Furthermore, the effects of the blade outlet angle on the performance are investigated and high performance design with simple structure for the mini turbo-pump would be considered.

  16. An evaluation of Turbo Prolog with an emphasis on its application to the development of expert systems

    NASA Technical Reports Server (NTRS)

    Loftin, Richard B.

    1987-01-01

    Turbo Prolog is a recently available, compiled version of the programming language Prolog. Turbo Prolog is designed to provide not only a Prolog compiler, but also a program development environment for the IBM Personal Computer family. An evaluation of Turbo Prolog was made, comparing its features to other versions of Prolog and to the community of languages commonly used in artificial intelligence (AI) research and development. Three programs were employed to determine the execution speed of Turbo Prolog applied to various problems. The results of this evaluation demonstrated that Turbo Prolog can perform much better than many commonly employed AI languages for numerically intensive problems and can equal the speed of development languages such as OPS5+ and CLIPS, running on the IBM PC. Applications for which Turbo Prolog is best suited include those which (1) lend themselves naturally to backward-chaining approaches, (2) require extensive use of mathematics, (3) contain few rules, (4) seek to make use of the window/color graphics capabilities of the IBM PC, and (5) require linkage to programs in other languages to form a complete executable image.

  17. Threshold-Based Bit Error Rate for Stopping Iterative Turbo Decoding in a Varying SNR Environment

    NASA Astrophysics Data System (ADS)

    Mohamad, Roslina; Harun, Harlisya; Mokhtar, Makhfudzah; Adnan, Wan Azizun Wan; Dimyati, Kaharudin

    2017-01-01

    Online bit error rate (BER) estimation (OBE) has been used as a stopping iterative turbo decoding criterion. However, the stopping criteria only work at high signal-to-noise ratios (SNRs), and fail to have early termination at low SNRs, which contributes to an additional iteration number and an increase in computational complexity. The failure of the stopping criteria is caused by the unsuitable BER threshold, which is obtained by estimating the expected BER performance at high SNRs, and this threshold does not indicate the correct termination according to convergence and non-convergence outputs (CNCO). Hence, in this paper, the threshold computation based on the BER of CNCO is proposed for an OBE stopping criterion (OBEsc). From the results, OBEsc is capable of terminating early in a varying SNR environment. The optimum number of iterations achieved by the OBEsc allows huge savings in decoding iteration number and decreasing the delay of turbo iterative decoding.

  18. Dynamic angle stability of an industrial turbo generator connected in power system

    NASA Astrophysics Data System (ADS)

    Grouni, S.; Hallak, M.; Aibeche, A.; Ramdani, A.; Bouallegue, K.

    2014-12-01

    This paper deals with the dynamic problem of oscillation and damping on an industrial turbo generator connected to infinite networks. A set of equations that governs the turbo generator connected to infinite bus are written in characteristic form. The power system stabilizer PSS applied in order to solve the problem of damping internal angle and operating power system synchronization. The PSS model described is inspired from Heffron-Philips model is applied on real parameters simulation under Matlab simulink. The results obtained from practical application are advantageous which variations of amplitude and time mitigation oscillations magnitude of electrical and mechanical output variables. This numerical experiment permits to gain more simplicity compared with several methods applied in a real operating prototyping systems. The PSS that is used will improve the dynamic stability.

  19. Turbo product codes and their application in the fourth-generation mobile communication system

    NASA Astrophysics Data System (ADS)

    He, Yejun; Zhu, Guangxi; Liu, Ying Zhuang; Liu, Jian

    2004-04-01

    In this paper, we firstly present turbo product codes (TPCs) for forward error correction (FEC) coding, including TPCs encoding process and decoding principle, and then compare TPCs with turbo convolutional codes (TCCs) error coding solution. The performance of TPCs is shown to be closer to the Shannon limit than TCCs. Secondly, we introduce TPCs" application in the 4th generation (4G) mobile communication system which is being developed in our country at present. The concept of TPC-OFDM system which promises higher code rate than conventional OFDM is first modified. Finally, simulation results show that the simplified 4G uplink systems offer Bit Error Rate of nearly 0 over IMT-2000 channel at Eb/N0 > 15dB.

  20. A New Turbo-shaft Engine Control Law during Variable Rotor Speed Transient Process

    NASA Astrophysics Data System (ADS)

    Hua, Wei; Miao, Lizhen; Zhang, Haibo; Huang, Jinquan

    2015-12-01

    A closed-loop control law employing compressor guided vanes is firstly investigated to solve unacceptable fuel flow dynamic change in single fuel control for turbo-shaft engine here, especially for rotorcraft in variable rotor speed process. Based on an Augmented Linear Quadratic Regulator (ALQR) algorithm, a dual-input, single-output robust control scheme is proposed for a turbo-shaft engine, involving not only the closed loop adjustment of fuel flow but also that of compressor guided vanes. Furthermore, compared to single fuel control, some digital simulation cases using this new scheme about variable rotor speed have been implemented on the basis of an integrated system of helicopter and engine model. The results depict that the command tracking performance to the free turbine rotor speed can be asymptotically realized. Moreover, the fuel flow transient process has been significantly improved, and the fuel consumption has been dramatically cut down by more than 2% while keeping the helicopter level fight unchanged.

  1. Block Transmissions over Doubly Selective Channels: Iterative Channel Estimation and Turbo Equalization

    NASA Astrophysics Data System (ADS)

    Fang, Kun; Rugini, Luca; Leus, Geert

    2010-12-01

    Modern wireless communication systems require high transmission rates, giving rise to frequency selectivity due to multipath propagation. In addition, high-mobility terminals and scatterers induce Doppler shifts that introduce time selectivity. Therefore, advanced techniques are needed to accurately model the time- and frequency-selective (i.e., doubly selective) channels and to counteract the related performance degradation. In this paper, we develop new receivers for orthogonal frequency-division multiplexing (OFDM) systems and single-carrier (SC) systems in doubly selective channels by embedding the channel estimation task within low-complexity block turbo equalizers. Linear minimum mean-squared error (MMSE) pilot-assisted channel estimators are presented, and the soft data estimates from the turbo equalizers are used to improve the quality of the channel estimates.

  2. Structural design and analysis of a Mach zero to five turbo-ramjet system

    NASA Technical Reports Server (NTRS)

    Spoth, Kevin A.; Moses, Paul L.

    1993-01-01

    The paper discusses the structural design and analysis of a Mach zero to five turbo-ramjet propulsion system for a Mach five waverider-derived cruise vehicle. The level of analysis detail necessary for a credible conceptual design is shown. The results of a finite-element failure mode sizing analysis for the engine primary structure is presented. The importance of engine/airframe integration is also discussed.

  3. DESIGN & DEVELOPMENT OF E-TURBO FOR SUV AND LIGHT TRUCK APPLICATIONS

    SciTech Connect

    Balis, C; Middlemass, C; Shahed, SM

    2003-08-24

    The purpose of the project is to develop an electronically controlled, electrically assisted turbocharging system, e-Turbo, for application to SUV and light truck class of passenger vehicles. Earlier simulation work had shown the benefits of e-Turbo system on increasing low-end torque and improving fuel economy. This paper will present further data from the literature to show that advanced turbocharging can enable diesel engine downsizing of 10-30% with 6-17% improvement in fuel economy. This is in addition to the fuel economy benefit that a turbocharged diesel engine offers over conventional gasoline engines. E-Turbo is necessary to get acceptable driving characteristics with downsized diesel engines. As a first step towards the development of this technology for SUV/light truck sized diesel engines (4-6 litre displacement), design concepts and hardware were evaluated for a smaller engine (2 litre displacement). It was felt that design and developments issues could be minimized, the concept proven progressively on the bench, on a small engine and then applied to a large Vee engine (one on each bank). After successful demonstration of the concept, large turbomachinery could be designed and built specifically for larger SUV sized diesel engines. This paper presents the results of development of e-Turbo for a 2 litre diesel engine. A detailed comparison of several electric assist technologies including permanent magnet, six-phase induction and conventional induction motor/generator technology was done. A comparison of switched reluctance motor technology was also done although detailed design was not carried out.

  4. Engineering & Performance of DuoTurbo: Microturbine with Counter-Rotating Runners

    NASA Astrophysics Data System (ADS)

    Biner, D.; Hasmatuchi, V.; Violante, D.; Richard, S.; Chevailler, S.; Andolfatto, L.; Avellan, F.; Münch, C.

    2016-11-01

    Considering the nuclear phase-out strategy of several European countries and the future tendency to promote renewable energies, the exploitation of small hydropower sites (<10 MW) becomes increasingly important. In this framework DuoTurbo Turbine, a new DuoTurbo-microturbine prototype for drinking water networks has been jointly developed by the HES-SO Valais//Wallis, the EPFL-Laboratory for Hydraulic Machines and industrial partners. The modular in-line “plug & play” technology requires low investment, reaching economic feasibility with an available power between 5 kW and 25 kW. One stage of the microturbine consists of two axial counter-rotating runners that form a compact independent unit. Each runner of the turbine holds its own rim generator, the DuoTurbo-configuration involving that each hydraulic runner is integral with each electrical rotor. The possibility of stacking several stages in series enables covering quite a wide range of hydraulic power and, thus, recovering a maximum of energy dissipated in release valves of water supply systems. The present work introduces the global concept of the implemented prototype of the DuoTurbo-microturbine, to target a maximal injected power of 5 kW for a discharge of 9 l/s and a head of 24.5 m per stage. The main features of the hydraulic, the mechanical, the electrical and the electronic design are presented. The hydraulic performance is, then, assessed using CFD simulations for the expected operating range. Finally, the performance measurements of the single-stage prototype installed in the hydraulic test rig of the HES-SO Valais//Wallis are presented.

  5. Optimizations of a Turbo-Like Decoder for Deep-Space Optical Communications

    NASA Astrophysics Data System (ADS)

    Cheng, M. K.; Nakashima, M. A.; Moision, B. E.; Hamkins, J.

    2007-02-01

    The National Aeronautics and Space Administration has developed a capacity-approaching modulation and coding scheme that comprises a serial concatenation of an inner accumulate pulse-position modulation and an outer convolutional code for deep-space optical communications. Decoding of this serially concatenated pulse-position modulation (SCPPM) code uses a turbo-like algorithm. However, the inner code trellis contains many parallel edges that are not typical in standard turbo codes and, therefore, a straightforward application of classical turbo decoding is very inefficient. Here, we present various optimizations applicable in hardware implementation of the SCPPM decoder. More specifically, we feature a Super Gamma computation to efficiently handle parallel trellis edges, a "maxstar top 2" circuit fit for pipelining, a modified two's complement subtraction circuit with a shorter path delay, and a cyclic redundancy check circuit for window-based turbo decoders. We also present a polynomial interleaver where current interleaver positions can be calculated from previous positions. This recursive interleaver property enables an algorithmic realization in which no memory is needed to store the interleaver mappings. Using the featured optimizations, we implement a 6.72 megabits-per-second (Mbps) SCPPM decoder on a single field-programmable gate array (FPGA). Compared to the current data rate of 256 kbps from Mars, the SCPPM-coded scheme represents a throughput increase of more than twenty-six fold. Extension to a 50-Mbps decoder on a board with multiple FPGAs follows naturally. We show through hardware simulations that the SCPPM-coded system can operate within 1 dB of the Shannon capacity at nominal operating conditions.

  6. Validation of Heat Transfer and Film Cooling Capabilities of the 3-D RANS Code TURBO

    NASA Technical Reports Server (NTRS)

    Shyam, Vikram; Ameri, Ali; Chen, Jen-Ping

    2010-01-01

    The capabilities of the 3-D unsteady RANS code TURBO have been extended to include heat transfer and film cooling applications. The results of simulations performed with the modified code are compared to experiment and to theory, where applicable. Wilcox s k-turbulence model has been implemented to close the RANS equations. Two simulations are conducted: (1) flow over a flat plate and (2) flow over an adiabatic flat plate cooled by one hole inclined at 35 to the free stream. For (1) agreement with theory is found to be excellent for heat transfer, represented by local Nusselt number, and quite good for momentum, as represented by the local skin friction coefficient. This report compares the local skin friction coefficients and Nusselt numbers on a flat plate obtained using Wilcox's k-model with the theory of Blasius. The study looks at laminar and turbulent flows over an adiabatic flat plate and over an isothermal flat plate for two different wall temperatures. It is shown that TURBO is able to accurately predict heat transfer on a flat plate. For (2) TURBO shows good qualitative agreement with film cooling experiments performed on a flat plate with one cooling hole. Quantitatively, film effectiveness is under predicted downstream of the hole.

  7. Performance Analyses of 38 kWe Turbo-Machine Unit for Space Reactor Power Systems

    NASA Astrophysics Data System (ADS)

    Gallo, Bruno M.; El-Genk, Mohamed S.

    2008-01-01

    This paper developed a design and investigated the performance of 38 kWe turbo-machine unit for space nuclear reactor power systems with Closed Brayton Cycle (CBC) energy conversion. The compressor and turbine of this unit are scaled versions of the NASA's BRU developed in the sixties and seventies. The performance results of turbo-machine unit are calculated for rotational speed up to 45 krpm, variable reactor thermal power and system pressure, and fixed turbine and compressor inlet temperatures of 1144 K and 400 K. The analyses used a detailed turbo-machine model developed at the University of New Mexico that accounts for the various energy losses in the compressor and turbine and the effect of compressibility of the He-Xe (40 mole/g) working fluid with increased flow rate. The model also accounts for the changes in the physical and transport properties of the working fluid with temperature and pressure. Results show that a unit efficiency of 24.5% is achievable at rotation speed of 45 krpm and system pressure of 0.75 MPa, assuming shaft and electrical generator efficiencies of 86.7% and 90%. The corresponding net electric power output of the unit is 38.5 kWe, the flow rate of the working fluid is 1.667 kg/s, the pressure ratio and polytropic efficiency for the compressor are 1.60 and 83.1%, and 1.51 and 88.3% for the turbine.

  8. Spectrally-efficient differential turbo-coded modulation for multi-gigabit satellite links

    NASA Astrophysics Data System (ADS)

    Tabor, B. H.; Sacchi, C.; Schlegel, C.

    Efficient exploitation of the wide bandwidth available in the EHF (extremely high frequency) domain will be a main pillar for the development of future-generation terabit satellite networks. State-of-the-art systems use spectrally-efficient coded modulations, which are based on coherent demodulation that requires the use of complex and expensive analog PLL circuitry, which are vulnerable to high Doppler shifts and phase noise, the latter, being a significant impairment in the W-band. The latest trends in digital communications are to use fully digital receivers. Therefore, we consider a novel modulation method based on differential turbo-coded modulation and A-Posteriori-Probability (APP) channel estimation for application in multi-gigabit W-band satellite links. The proposed scheme utilizes the combination of an outer 2/3 binary parity channel code and differential 8-PSK modulation, similar to a binary repeat-accumulate serial turbo coding. The turbo-demodulator uses a double-spread interleaver and Log-MAP decoding performed on the 8-PSK trellis. Counteracting channel impairments and frequency drifts is primarily accomplished by APP channel estimation which is integrated into the differential demodulator, and consists of a simple smoothing filter. Preliminary results have shown a robust behavior of the system, achieving high link availability.

  9. The Case for Distributed Engine Control in Turbo-Shaft Engine Systems

    NASA Technical Reports Server (NTRS)

    Culley, Dennis E.; Paluszewski, Paul J.; Storey, William; Smith, Bert J.

    2009-01-01

    The turbo-shaft engine is an important propulsion system used to power vehicles on land, sea, and in the air. As the power plant for many high performance helicopters, the characteristics of the engine and control are critical to proper vehicle operation as well as being the main determinant to overall vehicle performance. When applied to vertical flight, important distinctions exist in the turbo-shaft engine control system due to the high degree of dynamic coupling between the engine and airframe and the affect on vehicle handling characteristics. In this study, the impact of engine control system architecture is explored relative to engine performance, weight, reliability, safety, and overall cost. Comparison of the impact of architecture on these metrics is investigated as the control system is modified from a legacy centralized structure to a more distributed configuration. A composite strawman system which is typical of turbo-shaft engines in the 1000 to 2000 hp class is described and used for comparison. The overall benefits of these changes to control system architecture are assessed. The availability of supporting technologies to achieve this evolution is also discussed.

  10. Performance Analyses of 38 kWe Turbo-Machine Unit for Space Reactor Power Systems

    SciTech Connect

    Gallo, Bruno M.; El-Genk, Mohamed S.

    2008-01-21

    This paper developed a design and investigated the performance of 38 kWe turbo-machine unit for space nuclear reactor power systems with Closed Brayton Cycle (CBC) energy conversion. The compressor and turbine of this unit are scaled versions of the NASA's BRU developed in the sixties and seventies. The performance results of turbo-machine unit are calculated for rotational speed up to 45 krpm, variable reactor thermal power and system pressure, and fixed turbine and compressor inlet temperatures of 1144 K and 400 K. The analyses used a detailed turbo-machine model developed at University of New Mexico that accounts for the various energy losses in the compressor and turbine and the effect of compressibility of the He-Xe (40 mole/g) working fluid with increased flow rate. The model also accounts for the changes in the physical and transport properties of the working fluid with temperature and pressure. Results show that a unit efficiency of 24.5% is achievable at rotation speed of 45 krpm and system pressure of 0.75 MPa, assuming shaft and electrical generator efficiencies of 86.7% and 90%. The corresponding net electric power output of the unit is 38.5 kWe, the flow rate of the working fluid is 1.667 kg/s, the pressure ratio and polytropic efficiency for the compressor are 1.60 and 83.1%, and 1.51 and 88.3% for the turbine.

  11. An Acquisition Guide for Executives

    EPA Pesticide Factsheets

    This guide covers the following subjects; What is Acquisition?, Purpose and Primary Functions of the Agency’s Acquisition System, Key Organizations in Acquisitions, Legal Framework, Key Players in Acquisitions, Acquisition Process, Acquisition Thresholds

  12. An Off-Grid Turbo Channel Estimation Algorithm for Millimeter Wave Communications.

    PubMed

    Han, Lingyi; Peng, Yuexing; Wang, Peng; Li, Yonghui

    2016-09-22

    The bandwidth shortage has motivated the exploration of the millimeter wave (mmWave) frequency spectrum for future communication networks. To compensate for the severe propagation attenuation in the mmWave band, massive antenna arrays can be adopted at both the transmitter and receiver to provide large array gains via directional beamforming. To achieve such array gains, channel estimation (CE) with high resolution and low latency is of great importance for mmWave communications. However, classic super-resolution subspace CE methods such as multiple signal classification (MUSIC) and estimation of signal parameters via rotation invariant technique (ESPRIT) cannot be applied here due to RF chain constraints. In this paper, an enhanced CE algorithm is developed for the off-grid problem when quantizing the angles of mmWave channel in the spatial domain where off-grid problem refers to the scenario that angles do not lie on the quantization grids with high probability, and it results in power leakage and severe reduction of the CE performance. A new model is first proposed to formulate the off-grid problem. The new model divides the continuously-distributed angle into a quantized discrete grid part, referred to as the integral grid angle, and an offset part, termed fractional off-grid angle. Accordingly, an iterative off-grid turbo CE (IOTCE) algorithm is proposed to renew and upgrade the CE between the integral grid part and the fractional off-grid part under the Turbo principle. By fully exploiting the sparse structure of mmWave channels, the integral grid part is estimated by a soft-decoding based compressed sensing (CS) method called improved turbo compressed channel sensing (ITCCS). It iteratively updates the soft information between the linear minimum mean square error (LMMSE) estimator and the sparsity combiner. Monte Carlo simulations are presented to evaluate the performance of the proposed method, and the results show that it enhances the angle detection

  13. Serial-Turbo-Trellis-Coded Modulation with Rate-1 Inner Code

    NASA Technical Reports Server (NTRS)

    Divsalar, Dariush; Dolinar, Sam; Pollara, Fabrizio

    2004-01-01

    Serially concatenated turbo codes have been proposed to satisfy requirements for low bit- and word-error rates and for low (in comparison with related previous codes) complexity of coding and decoding algorithms and thus low complexity of coding and decoding circuitry. These codes are applicable to such high-level modulations as octonary phase-shift keying (8PSK) and 16-state quadrature amplitude modulation (16QAM); the signal product obtained by applying one of these codes to one of these modulations is denoted, generally, as serially concatenated trellis-coded modulation (SCTCM). These codes could be particularly beneficial for communication systems that must be designed and operated subject to limitations on bandwidth and power. Some background information is prerequisite to a meaningful summary of this development. Trellis-coded modulation (TCM) is now a well-established technique in digital communications. A turbo code combines binary component codes (which typically include trellis codes) with interleaving. A turbo code of the type that has been studied prior to this development is composed of parallel concatenated convolutional codes (PCCCs) implemented by two or more constituent systematic encoders joined through one or more interleavers. The input information bits feed the first encoder and, after having been scrambled by the interleaver, enter the second encoder. A code word of a parallel concatenated code consists of the input bits to the first encoder followed by the parity check bits of both encoders. The suboptimal iterative decoding structure for such a code is modular, and consists of a set of concatenated decoding modules one for each constituent code connected through an interleaver identical to the one in the encoder side. Each decoder performs weighted soft decoding of the input sequence. PCCCs yield very large coding gains at the cost of a reduction in the data rate and/or an increase in bandwidth.

  14. An Off-Grid Turbo Channel Estimation Algorithm for Millimeter Wave Communications

    PubMed Central

    Han, Lingyi; Peng, Yuexing; Wang, Peng; Li, Yonghui

    2016-01-01

    The bandwidth shortage has motivated the exploration of the millimeter wave (mmWave) frequency spectrum for future communication networks. To compensate for the severe propagation attenuation in the mmWave band, massive antenna arrays can be adopted at both the transmitter and receiver to provide large array gains via directional beamforming. To achieve such array gains, channel estimation (CE) with high resolution and low latency is of great importance for mmWave communications. However, classic super-resolution subspace CE methods such as multiple signal classification (MUSIC) and estimation of signal parameters via rotation invariant technique (ESPRIT) cannot be applied here due to RF chain constraints. In this paper, an enhanced CE algorithm is developed for the off-grid problem when quantizing the angles of mmWave channel in the spatial domain where off-grid problem refers to the scenario that angles do not lie on the quantization grids with high probability, and it results in power leakage and severe reduction of the CE performance. A new model is first proposed to formulate the off-grid problem. The new model divides the continuously-distributed angle into a quantized discrete grid part, referred to as the integral grid angle, and an offset part, termed fractional off-grid angle. Accordingly, an iterative off-grid turbo CE (IOTCE) algorithm is proposed to renew and upgrade the CE between the integral grid part and the fractional off-grid part under the Turbo principle. By fully exploiting the sparse structure of mmWave channels, the integral grid part is estimated by a soft-decoding based compressed sensing (CS) method called improved turbo compressed channel sensing (ITCCS). It iteratively updates the soft information between the linear minimum mean square error (LMMSE) estimator and the sparsity combiner. Monte Carlo simulations are presented to evaluate the performance of the proposed method, and the results show that it enhances the angle detection

  15. Performance measurements of turbo-coded bandwidth efficient modulations in the presence of a nonlinear TWTA

    NASA Astrophysics Data System (ADS)

    Grayver, E.; Dafesh, P.; Muha, M.; Moulthrop, A.

    2005-08-01

    This paper presents results obtained from an end-to-end, proof-of-concept system for a GOES-R series satellite communication system, that integrates a multilevel modulator, turbo coding, and a nonlinear traveling wave tube amplifier (TWTA). Multilevel modulation schemes allow high-speed data communications in a limited amount of spectrum, enabling higher data rates for GOES-R user downlink, as compared to the GOES user downlinks within the existing L-band allocation. Bandwidth-efficient modulations, such as 8-PSK and 16-QAM allow transmission of 3 or 4 times more data in the same amount of bandwidth than a standard BPSK modulation. This improvement, however, comes at the price of increased linearity requirements for the end-to-end link. This constraint is especially important for the power amplifier, which is typically a nonlinear device. TWTAs are frequently used on satellites for transmitter power amplification. These high-power devices operate at highest efficiency when in saturation mode. However, their transfer function is highly nonlinear in this mode, causing significant degradation in the link bit error rate (BER). Applying forward error correction based on turbo codes improves the BER by providing an additional noise margin of up to 5 dB. This paper presents measured BER curves for different Turbo codes, taken at different power levels relative to saturation. The results demonstrate that very low BER (below 10-10)can be achieved when using 8-PSK even when operating within 1 dB of saturation. This research and study was done by the Aerospace corporation in support of NOAA, and its future GOES-R series satellites.

  16. Quiet High Speed Fan (QHSF) Flutter Calculations Using the TURBO Code

    NASA Technical Reports Server (NTRS)

    Bakhle, Milind A.; Srivastava, Rakesh; Keith, Theo G., Jr.; Min, James B.; Mehmed, Oral

    2006-01-01

    A scale model of the NASA/Honeywell Engines Quiet High Speed Fan (QHSF) encountered flutter wind tunnel testing. This report documents aeroelastic calculations done for the QHSF scale model using the blade vibration capability of the TURBO code. Calculations at design speed were used to quantify the effect of numerical parameters on the aerodynamic damping predictions. This numerical study allowed the selection of appropriate values of these parameters, and also allowed an assessment of the variability in the calculated aerodynamic damping. Calculations were also done at 90 percent of design speed. The predicted trends in aerodynamic damping corresponded to those observed during testing.

  17. Small, high-speed bearing technology for cryogenic turbo-pumps

    NASA Technical Reports Server (NTRS)

    Winn, L. W.; Eusepi, M. W.; Smalley, A. J.

    1974-01-01

    The design of 20-mm bore ball bearings is described for cryogenic turbo-machinery applications, operating up to speeds of 120,000 rpm. A special section is included on the design of hybrid bearings. Each hybrid bearing is composed of a ball bearing in series with a conventional pressurized fluid-film journal bearing. Full details are presented on the design of a test vehicle which possesses the capability of testing the above named bearings within the given speed range under externally applied radial and axial loads.

  18. Minimum Kullback-Leibler-Based Turbo Multiuser Detector over Decomposition CDMA Signal

    NASA Astrophysics Data System (ADS)

    Ploysuwan, Tuchsanai; Tantiphanwadi, Sawat; Teekaput, Prasit

    In this paper, we develop a new iterative turbo multiuser detector for direct sequence code-division multiple access (DS-CDMA) systems over unknown frequency-selective channels by decomposing the observation signal into a number of signal components. Virtual trellis model representing the ISI channel for each separating signal user is designed to generate extrinsic probability in term of BCJR algorithm for exchange with a single channel decoder as priori information. Minimum kullback-leibler (MKL) framework is derived to calculate numerical channel estimation and extrinsic probability. In comparison with other similar receiver, simulation results demonstrate that the proposed solution achieves the desirable performance.

  19. A construction of quantum turbo product codes based on CSS-type quantum convolutional codes

    NASA Astrophysics Data System (ADS)

    Xiao, Hailin; Ni, Ju; Xie, Wu; Ouyang, Shan

    As in classical coding theory, turbo product codes (TPCs) through serially concatenated block codes can achieve approximatively Shannon capacity limit and have low decoding complexity. However, special requirements in the quantum setting severely limit the structures of turbo product codes (QTPCs). To design a good structure for QTPCs, we present a new construction of QTPCs with the interleaved serial concatenation of CSS(L1,L2)-type quantum convolutional codes (QCCs). First, CSS(L1,L2)-type QCCs are proposed by exploiting the theory of CSS-type quantum stabilizer codes and QCCs, and the description and the analysis of encoder circuit are greatly simplified in the form of Hadamard gates and C-NOT gates. Second, the interleaved coded matrix of QTPCs is derived by quantum permutation SWAP gate definition. Finally, we prove the corresponding relation on the minimum Hamming distance of QTPCs associated with classical TPCs, and describe the state diagram of encoder and decoder of QTPCs that have a highly regular structure and simple design idea.

  20. Turbo-Brayton cryocooler technology for low-temperature space applications

    NASA Astrophysics Data System (ADS)

    Zagarola, Mark V.; Breedlove, Jeffrey F.; McCormick, John A.; Swift, Walter L.

    2003-03-01

    High performance, low temperature cryocoolers are being developed for future space-borne telescopes and instruments. To meet mission objectives, these coolers must be compact, lightweight, have low input power, operate reliably for 5-10 years, and produce no disturbances that would affect the pointing accuracy of the instruments. This paper describes progress in the development of turbo-Brayton cryocoolers addressing cooling in the 5 K to 20 K temperature range for loads of up to 300 mW. The key components for these cryocoolers are the miniature, high-speed turbomachines and the high performance recuperative heat exchangers. The turbomachines use gas-bearings to support the low mass, high speed rotors, resulting in negligible vibration and long life. Precision fabrication techniques are used to produce the necessary micro-scale geometric features that provide for high cycle efficiencies at these reduced sizes. Turbo-Brayton cryocoolers for higher temperatures and loads have been successfully developed for space applications. For efficient operation at low temperatures and capacities, advances in the core technologies have been pursued. Performance test results of a new, low poer compressor will be presented, and early cryogenic test results on a low temperature expansion turbine will be discussed. Projections for several low temperature cooler configurations are summarized.

  1. Optimal control design of turbo spin‐echo sequences with applications to parallel‐transmit systems

    PubMed Central

    Hoogduin, Hans; Hajnal, Joseph V.; van den Berg, Cornelis A. T.; Luijten, Peter R.; Malik, Shaihan J.

    2016-01-01

    Purpose The design of turbo spin‐echo sequences is modeled as a dynamic optimization problem which includes the case of inhomogeneous transmit radiofrequency fields. This problem is efficiently solved by optimal control techniques making it possible to design patient‐specific sequences online. Theory and Methods The extended phase graph formalism is employed to model the signal evolution. The design problem is cast as an optimal control problem and an efficient numerical procedure for its solution is given. The numerical and experimental tests address standard multiecho sequences and pTx configurations. Results Standard, analytically derived flip angle trains are recovered by the numerical optimal control approach. New sequences are designed where constraints on radiofrequency total and peak power are included. In the case of parallel transmit application, the method is able to calculate the optimal echo train for two‐dimensional and three‐dimensional turbo spin echo sequences in the order of 10 s with a single central processing unit (CPU) implementation. The image contrast is maintained through the whole field of view despite inhomogeneities of the radiofrequency fields. Conclusion The optimal control design sheds new light on the sequence design process and makes it possible to design sequences in an online, patient‐specific fashion. Magn Reson Med 77:361–373, 2017. © 2016 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine PMID:26800383

  2. Development of turbo-viscous pump with ceramic rotor assembly and oil-free driving unit

    SciTech Connect

    Murakami, Y.; Abe, T. , Naka Fusion Research Establishment, Naka-machi, Naka-gun, Ibaraki-ken, Japan ); Ohsawa, H.; Hata, S. )

    1991-05-01

    In order to establish a dynamic pumping system for fusion reactors and other advanced vacuum devices, a new type of roughing pump named turbo-viscous pump has been developed. The construction of the pump features a multistage ceramic (silicon nitride) rotor assembly and an oil-free driving unit. The rotor assembly has parallel rotor disks, between which project stator disks from the outer casing with rotor-stator clearances {lt}100 {mu}m, and a shaft with gas turbine blades. Spiral grooves are cut on either side of the rotor or stator disk of each stage, each of them starting near the center (or at the periphery) and ending at the periphery (or near the center). The pump shaft is supported by gas bearings and is driven by gas impulse turbines at {similar to}25 000 rpm. No lubricating or cooling oil is used. The turbo-viscous pump works in a wide pressure range from atmospheric pressure to 10{sup {minus}3} Pa. The pumping speed and ultimate pressure attained so far are 0.28 m{sup 3}/min (at inlet pressures between 10{sup {minus}1} and 10{sup 2} Pa) and 1{times}10{sup {minus}3} Pa, respectively.

  3. Design and Development of a 200-kW Turbo-Electric Distributed Propulsion Testbed

    NASA Technical Reports Server (NTRS)

    Papathakis, Kurt V.; Kloesel, Kurt J.; Lin, Yohan; Clarke, Sean; Ediger, Jacob J.; Ginn, Starr

    2016-01-01

    The National Aeronautics and Space Administration (NASA) Armstrong Flight Research Center (AFRC) (Edwards, California) is developing a Hybrid-Electric Integrated Systems Testbed (HEIST) Testbed as part of the HEIST Project, to study power management and transition complexities, modular architectures, and flight control laws for turbo-electric distributed propulsion technologies using representative hardware and piloted simulations. Capabilities are being developed to assess the flight readiness of hybrid electric and distributed electric vehicle architectures. Additionally, NASA will leverage experience gained and assets developed from HEIST to assist in flight-test proposal development, flight-test vehicle design, and evaluation of hybrid electric and distributed electric concept vehicles for flight safety. The HEIST test equipment will include three trailers supporting a distributed electric propulsion wing, a battery system and turbogenerator, dynamometers, and supporting power and communication infrastructure, all connected to the AFRC Core simulation. Plans call for 18 high performance electric motors that will be powered by batteries and the turbogenerator, and commanded by a piloted simulation. Flight control algorithms will be developed on the turbo-electric distributed propulsion system.

  4. Syntax acquisition.

    PubMed

    Crain, Stephen; Thornton, Rosalind

    2012-03-01

    Every normal child acquires a language in just a few years. By 3- or 4-years-old, children have effectively become adults in their abilities to produce and understand endlessly many sentences in a variety of conversational contexts. There are two alternative accounts of the course of children's language development. These different perspectives can be traced back to the nature versus nurture debate about how knowledge is acquired in any cognitive domain. One perspective dates back to Plato's dialog 'The Meno'. In this dialog, the protagonist, Socrates, demonstrates to Meno, an aristocrat in Ancient Greece, that a young slave knows more about geometry than he could have learned from experience. By extension, Plato's Problem refers to any gap between experience and knowledge. How children fill in the gap in the case of language continues to be the subject of much controversy in cognitive science. Any model of language acquisition must address three factors, inter alia: 1. The knowledge children accrue; 2. The input children receive (often called the primary linguistic data); 3. The nonlinguistic capacities of children to form and test generalizations based on the input. According to the famous linguist Noam Chomsky, the main task of linguistics is to explain how children bridge the gap-Chomsky calls it a 'chasm'-between what they come to know about language, and what they could have learned from experience, even given optimistic assumptions about their cognitive abilities. Proponents of the alternative 'nurture' approach accuse nativists like Chomsky of overestimating the complexity of what children learn, underestimating the data children have to work with, and manifesting undue pessimism about children's abilities to extract information based on the input. The modern 'nurture' approach is often referred to as the usage-based account. We discuss the usage-based account first, and then the nativist account. After that, we report and discuss the findings of several

  5. The Effect of Classic and Web Based Educational Application, Applied for Turbo Pascal Lesson, on Student Success Level

    ERIC Educational Resources Information Center

    Bintas, Jale; Barut, Asim

    2008-01-01

    The aim of research is to compare difference between tenth class students and determine their level of success about classic and web based educational applications of Turbo Pascal lesson. This research was applied to 10 A and 10 TLB students of Izmir Karsikaya Anatolian Technical and industrial high school computer department in second term of…

  6. Two high-density recording methods with run-length limited turbo code for holographic data storage system

    NASA Astrophysics Data System (ADS)

    Nakamura, Yusuke; Hoshizawa, Taku

    2016-09-01

    Two methods for increasing the data capacity of a holographic data storage system (HDSS) were developed. The first method is called “run-length-limited (RLL) high-density recording”. An RLL modulation has the same effect as enlarging the pixel pitch; namely, it optically reduces the hologram size. Accordingly, the method doubles the raw-data recording density. The second method is called “RLL turbo signal processing”. The RLL turbo code consists of \\text{RLL}(1,∞ ) trellis modulation and an optimized convolutional code. The remarkable point of the developed turbo code is that it employs the RLL modulator and demodulator as parts of the error-correction process. The turbo code improves the capability of error correction more than a conventional LDPC code, even though interpixel interference is generated. These two methods will increase the data density 1.78-fold. Moreover, by simulation and experiment, a data density of 2.4 Tbit/in.2 is confirmed.

  7. Defense Acquisition Workforce Modernization

    DTIC Science & Technology

    2010-07-01

    Acquisition , Technology & Logistics, 2000). PBSA “involves acquisition strategies, methods, and techniques that describe and communicate measurable ... Acquisition Workforce Distribution of DoD Workforce and Attrition Rates Seperation Rates Distribution of Workforce by Years of Service 38 A final issue... measurement . 14 Provisions within the IMPROVE Act demand greater accountability from the acquisition workforce, improve financial management, expand

  8. Investigating Second Language Acquisition.

    ERIC Educational Resources Information Center

    Jordens, Peter, Ed.; Lalleman, Josine, Ed.

    Essays in second language acquisition include: "The State of the Art in Second Language Acquisition Research" (Josine Lalleman); "Crosslinguistic Influence with Special Reference to the Acquisition of Grammar" (Michael Sharwood Smith); "Second Language Acquisition by Adult Immigrants: A Multiple Case Study of Turkish and…

  9. Evaluation of the WARP-turbo spin echo sequence for 3 Tesla magnetic resonance imaging of stifle joints in dogs with stainless steel tibial plateau leveling osteotomy implants.

    PubMed

    Simpler, Renee E; Kerwin, Sharon C; Eichelberger, Bunita M; Wall, Corey R; Thompson, James A; Padua, Abraham; Purdy, David; Griffin, John F

    2014-01-01

    Susceptibility artifacts caused by ferromagnetic implants compromise magnetic resonance imaging (MRI) of the canine stifle after tibial plateau leveling osteotomy (TPLO) procedures. The WARP-turbo spin echo sequence is being developed to mitigate artifacts and utilizes slice encoding for metal artifact reduction. The aim of the current study was to evaluate the WARP-turbo spin echo sequence for imaging post TPLO canine stifle joints. Proton density weighted images of 19 canine cadaver limbs were made post TPLO using a 3 Tesla MRI scanner. Susceptibility artifact sizes were recorded and compared for WARP vs. conventional turbo spin echo sequences. Three evaluators graded depiction quality for the tibial tuberosity, medial and lateral menisci, tibial osteotomy, and caudal cruciate ligament as sufficient or insufficient to make a diagnosis. Artifacts were subjectively smaller and local structures were better depicted in WARP-turbo spin echo images. Signal void area was also reduced by 75% (sagittal) and 49% (dorsal) in WARP vs. conventional turbo spin echo images. Evaluators were significantly more likely to grade local anatomy depiction as adequate for making a diagnosis in WARP-turbo spin echo images in the sagittal but not dorsal plane. The proportion of image sets with anatomic structure depiction graded adequate to make a diagnosis ranged from 28 to 68% in sagittal WARP-turbo spin echo images compared to 0-19% in turbo spin echo images. Findings indicated that the WARP-turbo spin echo sequence reduces the severity of susceptibility artifacts in canine stifle joints post TPLO. However, variable depiction of local anatomy warrants further refinement of the technique.

  10. Evaluation of Image Quality in Three-dimensional Fat-suppressed T1-weighted Images with Fast Acquisition Mode for Upper Abdomen.

    PubMed

    Saito, Shigeyoshi; Tanaka, Keiko; Tarewaki, Hiroyuki; Koyama, Yoshihiro; Hashido, Takashi

    We compared the uniformity of fat-suppression and image quality using three-dimensional fat-suppressed T1-weighted gradient-echo sequences that are liver acquisition with volume acceleration (LAVA) and Turbo-LAVA at 3.0T-MRI. The subjects were seven patients with liver disease (mean age, 66.7±8.2 years). The axial slices of two LAVA sequences were used for the comparison of the uniformity of fat-suppression and image quality at a region-of-interest (ROI) of the liver dome, the porta, and the renal hilum. To yield a quantitative measurement of the uniformity of fat suppression, the percentage standard deviation (%SD) was calculated by comparing two sequences. For image signal to noise ratio (SNR), the contrast between the liver and fat (Cliver-fat), and the liver and muscle (Cliver-muscle), the other ROIs were placed in the superficial fat, liver, spleen, pancreas, and muscle. The %SD in Turbo-LAVA (28.1±16.8%) was lower than that in LAVA (41.5±13.4%). The SNRs in Turbo-LAVA (17.8±4.1 [liver], 12.5±3.0 [pancreas], 14.7±1.6 [spleen], 8.2±3.5 [fat]) were lower than those in LAVA (20.9±6.1 [liver], 16.8±4.1 [pancreas], 17.4±2.4 [spleen], 12.0±4.5 [fat]). While, the Cliver-fat in the Turbo-LAVA (0.72±0.06) was significantly higher than that in LAVA (0.59±0.07). Turbo-LAVA sequence offers superior and more homogenous fat-suppression in comparison to LAVA sequence.

  11. Empirical study of classification process for two-stage turbo air classifier in series

    NASA Astrophysics Data System (ADS)

    Yu, Yuan; Liu, Jiaxiang; Li, Gang

    2013-05-01

    The suitable process parameters for a two-stage turbo air classifier are important for obtaining the ultrafine powder that has a narrow particle-size distribution, however little has been published internationally on the classification process for the two-stage turbo air classifier in series. The influence of the process parameters of a two-stage turbo air classifier in series on classification performance is empirically studied by using aluminum oxide powders as the experimental material. The experimental results show the following: 1) When the rotor cage rotary speed of the first-stage classifier is increased from 2 300 r/min to 2 500 r/min with a constant rotor cage rotary speed of the second-stage classifier, classification precision is increased from 0.64 to 0.67. However, in this case, the final ultrafine powder yield is decreased from 79% to 74%, which means the classification precision and the final ultrafine powder yield can be regulated through adjusting the rotor cage rotary speed of the first-stage classifier. 2) When the rotor cage rotary speed of the second-stage classifier is increased from 2 500 r/min to 3 100 r/min with a constant rotor cage rotary speed of the first-stage classifier, the cut size is decreased from 13.16 μm to 8.76 μm, which means the cut size of the ultrafine powder can be regulated through adjusting the rotor cage rotary speed of the second-stage classifier. 3) When the feeding speed is increased from 35 kg/h to 50 kg/h, the "fish-hook" effect is strengthened, which makes the ultrafine powder yield decrease. 4) To weaken the "fish-hook" effect, the equalization of the two-stage wind speeds or the combination of a high first-stage wind speed with a low second-stage wind speed should be selected. This empirical study provides a criterion of process parameter configurations for a two-stage or multi-stage classifier in series, which offers a theoretical basis for practical production.

  12. Vibration reduction in advanced composite turbo-fan blades using embedded damping materials

    NASA Astrophysics Data System (ADS)

    Kosmatka, John B.; Lapid, Alex J.; Mehmed, Oral

    1996-05-01

    A preliminary design and analysis procedure for locating an integral damping treatment in composite turbo-propeller blades has been developed. This finite element based approach, which is based upon the modal strain energy method, is used to size and locate the damping material patch so that the damping (loss factor) is maximized in a particular mode while minimizing the overall stiffness loss (minimal reductions in the structural natural frequencies). Numerical results are presented to illustrate the variation in the natural frequencies and damping levels as a result of stacking sequence, integral damping patch size and location, and border materials. Experimental studies were presented using flat and pretwisted (30 degrees) integrally damped composite blade-like structures to show how a small internal damping patch can significantly increase the damping levels without sacrificing structural integrity. Moreover, the use of a soft border material around the patch can greatly increase the structural damping levels.

  13. Computational Aero-acoustics As a Tool For Turbo-machinery Noise Reduction

    NASA Technical Reports Server (NTRS)

    Dyson, Rodger W.

    2003-01-01

    This talk will provide an overview of the field of computational aero-acoustics and its use in fan noise prediction. After a brief history of computational fluid dynamics, some of the recent developments in computational aero-acoustics will be explored. Computational issues concerning sound wave production, propagation, and reflection in practical turbo-machinery applications will be discussed including: (a) High order/High Resolution Numerical Techniques. (b) High Resolution Boundary Conditions. [c] MIMD Parallel Computing. [d] Form of Governing Equations Useful for Simulations. In addition, the basic design of our Broadband Analysis Stator Simulator (BASS) code and its application to a 2 D rotor wake-stator interaction will be shown. An example of the noise produced by the wakes from a rotor impinging upon a stator cascade will be shown.

  14. Turbo test rig with hydroinertia air bearings for a palmtop gas turbine

    NASA Astrophysics Data System (ADS)

    Tanaka, Shuji; Isomura, Kousuke; Togo, Shin-ichi; Esashi, Masayoshi

    2004-11-01

    This paper describes a turbo test rig to test the compressor of a palmtop gas turbine generator at low temperature (<100 °C). Impellers are 10 mm in diameter and have three-dimensional blades machined using a five-axis NC milling machine. Hydroinertia bearings are employed in both radial and axial directions. The performance of the compressor was measured at 50% (435 000 rpm) and 60% (530 000 rpm) of the rated rotational speed (870 000 rpm) by driving a turbine using compressed air at room temperature. The measured pressure ratio is lower than the predicted value. This could be mainly because impeller tip clearance was larger than the designed value. The measured adiabatic efficiency is unrealistically high due to heat dissipation from compressed air. During acceleration toward the rated rotational speed, a shaft crashed to the bearing at 566 000 rpm due to whirl. At that time, the whirl ratio was 8.

  15. Performance Measurements of a Low Specific Speed TurboClaw® Compressor

    NASA Astrophysics Data System (ADS)

    Parra, J.; Cattell, R.; Etemad, S.; Pullen, K. R.

    2015-08-01

    Low specific speed compressors have been historically based on positive displacement machines. Attempts to bring advantages of turbomachinery such as oil free, low parts counts, low cost of manufacture, and reliability to low flow rate applications have not been sparse, but the principle difficulty has always been that the conventional turbomachine design operates at ultra-high speed to deliver low volume flow rates. This is synonymous with low efficiency due to higher losses (windage, surface finish, and tip clearances). The innovative TurboClaw® design is a low specific speed turbomachinery with forward swept impeller geometry. It owes its high efficiency and operational stability to careful design of its nearly tangential forward swept blading and diffuser geometry.

  16. [Resistance of Plasmodium falciparum to 3 antimalarials in Turbo (Antioquia, Colombia), 1998].

    PubMed

    Blair, S; Lacharme, L L; Fonseca, J C; Tobón, A

    2001-01-01

    In 1998 we determined in vivo and in vitro the frequency and the degree of resistance of Plasmodium falciparum to the three antimalarials (chloroquine, amodiaquine, and sulfadoxine/pyrimethamine) most utilized in the municipality of Turbo (in the area of Urabá, Antioquia, Colombia), in a sample representative of the population with malaria. We carried out clinical and parasitological analyses over a 14-day period using the standard test recommended by the World Health Organization. In vivo, P. falciparum showed resistance to chloroquine, amodiaquine, and sulfadoxine/pyrimethamine, with a frequency of 97%, 7%, and 13%, respectively. In vitro, the corresponding figures were 21%, 23%, and 9%, respectively. For chloroquine the level of agreement between the in vivo and in vitro results was 23%.

  17. Performance potential of air turbo-ramjet employing supersonic through-flow fan

    NASA Technical Reports Server (NTRS)

    Kepler, C. E.; Champagne, G. A.

    1989-01-01

    A study was conducted to assess the performance potential of a supersonic through-flow fan in an advanced engine designed to power a Mach-5 cruise vehicle. It included a preliminary evaluation of fan performance requirements and the desirability of supersonic versus subsonic combustion, the design and performance of supersonic fans, and the conceptual design of a single-pass air-turbo-rocket/ramjet engine for a Mach 5 cruise vehicle. The study results showed that such an engine could provide high thrust over the entire speed range from sea-level takeoff to Mach 5 cruise, especially over the transonic speed range, and high fuel specific impulse at the Mach 5 cruise condition, with the fan windmilling.

  18. Language Acquisition without an Acquisition Device

    ERIC Educational Resources Information Center

    O'Grady, William

    2012-01-01

    Most explanatory work on first and second language learning assumes the primacy of the acquisition phenomenon itself, and a good deal of work has been devoted to the search for an "acquisition device" that is specific to humans, and perhaps even to language. I will consider the possibility that this strategy is misguided and that language…

  19. Use of Xenon Difluoride to Clean Hazardous By-Products in Ion Implanter Source Housings, Turbo Pumps, and Fore-Lines

    NASA Astrophysics Data System (ADS)

    Despres, J.; Chambers, B.; Bishop, S.; Kaim, R.; Letaj, S.; Sergi, S.; Sweeney, J.; Tang, Y.; Wilson, S.; Yedave, S.

    2011-01-01

    This paper describes the use of xenon difluoride to clean deposits in the source housing, source turbo pump, and source turbo pump fore-line of ion implanters. Xenon difluoride has previously been shown to be effective in increasing the lifetime of the ion source1,2 and this paper presents an extension of the technology to other areas within the tool. Process by-products that are deposited in the source housing, turbo pump, and turbo pump fore-line can not only pose productivity issues, in the case of coatings on insulators, but can also be flammable and toxic in the case of deposits formed within the turbo pump and fore-line. The results presented in this paper detail the initial successful examples of using xenon difluoride to clean these deposits. ATMI has shown that xenon difluoride is capable of cleaning an insulator in an ion implanter. Typically during use an insulator will become increasingly coated with deposits that could lead to productivity problems. By introducing xenon difluoride into the source housing the insulator residues were effectively cleaned in-situ, thereby extending the maintenance interval and resulting in significant consumable savings. Similar deposits that form in the turbo pump and fore-line could not only lead to production problems due to turbo pump failure or fore-line build-up, but pose significant health risks during the ex-situ cleaning process. Through internal testing ATMI has shown that xenon difluoride is able to clean phosphorus and germanium deposits located within a turbo pump. Additionally, testing has demonstrated that the turbo pump fore-line can be cleaned in-situ without the need to remove these components, thereby virtually eliminating the possibility of fires. The cleaning reaction progress and by-products were monitored using FTIR spectrometry and thermocouples. In order to efficiently clean the source housing, turbo pump, and turbo pump fore-line xenon difluoride delivery must be optimized. This paper also details

  20. Use of Xenon Difluoride to Clean Hazardous By-Products in Ion Implanter Source Housings, Turbo Pumps, and Fore-Lines

    SciTech Connect

    Despres, J.; Chambers, B.; Bishop, S.; Kaim, R.; Letaj, S.; Sergi, S.; Sweeney, J.; Tang, Y.; Wilson, S.; Yedave, S.

    2011-01-07

    This paper describes the use of xenon difluoride to clean deposits in the source housing, source turbo pump, and source turbo pump fore-line of ion implanters. Xenon difluoride has previously been shown to be effective in increasing the lifetime of the ion source{sup 1,2} and this paper presents an extension of the technology to other areas within the tool. Process by-products that are deposited in the source housing, turbo pump, and turbo pump fore-line can not only pose productivity issues, in the case of coatings on insulators, but can also be flammable and toxic in the case of deposits formed within the turbo pump and fore-line. The results presented in this paper detail the initial successful examples of using xenon difluoride to clean these deposits.ATMI has shown that xenon difluoride is capable of cleaning an insulator in an ion implanter. Typically during use an insulator will become increasingly coated with deposits that could lead to productivity problems. By introducing xenon difluoride into the source housing the insulator residues were effectively cleaned in-situ, thereby extending the maintenance interval and resulting in significant consumable savings.Similar deposits that form in the turbo pump and fore-line could not only lead to production problems due to turbo pump failure or fore-line build-up, but pose significant health risks during the ex-situ cleaning process. Through internal testing ATMI has shown that xenon difluoride is able to clean phosphorus and germanium deposits located within a turbo pump. Additionally, testing has demonstrated that the turbo pump fore-line can be cleaned in-situ without the need to remove these components, thereby virtually eliminating the possibility of fires. The cleaning reaction progress and by-products were monitored using FTIR spectrometry and thermocouples.In order to efficiently clean the source housing, turbo pump, and turbo pump fore-line xenon difluoride delivery must be optimized. This paper also

  1. Preprocessor that Enables the Use of GridProTM Grids for Unsteady Reynolds-Averaged Navier-Stokes Code TURBO

    NASA Technical Reports Server (NTRS)

    Shyam, Vikram

    2010-01-01

    A preprocessor for the Computational Fluid Dynamics (CFD) code TURBO has been developed and tested. The preprocessor converts grids produced by GridPro (Program Development Company (PDC)) into a format readable by TURBO and generates the necessary input files associated with the grid. The preprocessor also generates information that enables the user to decide how to allocate the computational load in a multiple block per processor scenario.

  2. EARLY SYNTACTIC ACQUISITION.

    ERIC Educational Resources Information Center

    KELLEY, K.L.

    THIS PAPER IS A STUDY OF A CHILD'S EARLIEST PRETRANSFORMATIONAL LANGUAGE ACQUISITION PROCESSES. A MODEL IS CONSTRUCTED BASED ON THE ASSUMPTIONS (1) THAT SYNTACTIC ACQUISITION OCCURS THROUGH THE TESTING OF HYPOTHESES REFLECTING THE INITIAL STRUCTURE OF THE ACQUISITION MECHANISM AND THE LANGUAGE DATA TO WHICH THE CHILD IS EXPOSED, AND (2) THAT…

  3. Turbo-FSK, a physical layer for low-power wide-area networks: Analysis and optimization

    NASA Astrophysics Data System (ADS)

    Roth, Yoann; Doré, Jean-Baptiste; Ros, Laurent; Berg, Vincent

    2017-02-01

    As the Internet-of-Things is becoming a reality, the need for a new Low-Power Wide-Area (LPWA) network emerged in the last few years. Numerous low-cost devices will be connected, and this requires an optimization of the link budget: the physical layer needs to be designed highly energy efficient. The combination of M-ary orthogonal Frequency-Shift-Keying (M-FSK) modulation and coding in the same process has been shown to be a promising candidate when associated with an iterative receiver (turbo principle). In this work, we study this new digital transmission scheme, called Turbo-FSK. An EXtrinsic Information Transfer (EXIT) chart analysis is realized. The influence of the packet length is investigated, and the scheme is shown to stay energy efficiency even with short packet sizes. Comparison with LPWA current technologies is performed, showing the potential of this technology. xml:lang="fr"

  4. Operational Safety Assessment of Turbo Generators with Wavelet Rényi Entropy from Sensor-Dependent Vibration Signals

    PubMed Central

    Zhang, Xiaoli; Wang, Baojian; Chen, Xuefeng

    2015-01-01

    With the rapid development of sensor technology, various professional sensors are installed on modern machinery to monitor operational processes and assure operational safety, which play an important role in industry and society. In this work a new operational safety assessment approach with wavelet Rényi entropy utilizing sensor-dependent vibration signals is proposed. On the basis of a professional sensor and the corresponding system, sensor-dependent vibration signals are acquired and analyzed by a second generation wavelet package, which reflects time-varying operational characteristic of individual machinery. Derived from the sensor-dependent signals’ wavelet energy distribution over the observed signal frequency range, wavelet Rényi entropy is defined to compute the operational uncertainty of a turbo generator, which is then associated with its operational safety degree. The proposed method is applied in a 50 MW turbo generator, whereupon it is proved to be reasonable and effective for operation and maintenance. PMID:25894934

  5. Steady-state free precession sequences in myocardial first-pass perfusion MR imaging: comparison with TurboFLASH imaging.

    PubMed

    Hunold, Peter; Maderwald, Stefan; Eggebrecht, Holger; Vogt, Florian M; Barkhausen, Jörg

    2004-03-01

    The aim of this study was to compare the image quality of a saturation-recovery gradient-recalled echo (GRE; TurboFLASH) and a saturation-recovery SSFP (SR-TrueFISP) sequence for myocardial first-pass perfusion MRI. Eight patients with chronic myocardial infarction and 8 volunteers were examined with a TurboFLASH (TR 2.1 ms, TE 1 ms, FA 8 degrees ) and a SR-TrueFISP sequence (TR 2.1 ms, TE 0.9 ms, FA, 50 degrees ) on a 1.5 T scanner. During injection of 0.05 mmol/kg BW Gd-DTPA at 4 ml/s, three short axis slices (8 mm) of the left ventricle (LV) were simultaneously scanned during breath-hold. Maximum signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) between infarcted and normal myocardium, and percentage signal intensity change (PSIC) were measured within the LV lumen and in four regions of the LV myocardium for the three slices separately. For the LV lumen, SR-TrueFISP was superior in SNR and PSIC (factor 3.2 and 1.6, respectively). Mean maximum SNR, PSIC, and CNR during peak enhancement in the LV myocardium were higher for SR-TrueFISP compared with TurboFLASH (factor 2.4, 1.25, and 1.24, respectively). The SNR was higher in the septal portion of the ventricle than in anterior/posterior and lateral regions. The SR-TrueFISP provides higher SNR and improves image quality compared with TurboFLASH in first-pass myocardial perfusion MRI.

  6. A special comment on trace metals in the viscera of turbo marmoratus, a toxic snail, on Ryukyu Island.

    PubMed

    Yamada, Masa-Oki; Fujimori, Ken; Yamada, Gen; Satoh, Hiroyasu; Tohno, Setsuko; Tohno, Yoshiyuki; Moriwake, Yumi; Azuma, Cho; Minami, Takeshi

    2003-12-01

    Trace metals in the viscera of Turbo marmoratus, a huge conical spire, in the coral reef of Ryukyu Island were analyzed. The highest amount of Zn and Fe was detectable in the midgut gland known to be polluted by saxitoxin. This intestine maintained a considerable amount of Si (higher than Ca) which fluctuated in parallel with the taurine amount. These data suggest that the viscera of the alimentary tract accumulate some metals, especially Zn and Fe.

  7. Design validation of an air cooled turbo generator by using fibre optic sensors in a shop test

    NASA Astrophysics Data System (ADS)

    Bosselmann, T.; Willsch, M.; Villnow, M.; Strack, S.; Chernogorski, V.; Weidner, J. R.; Roeding, R.; Schwanengel, U.; Trefflich, L.; Lindholm, S.; Abromitis, E.

    2012-06-01

    The increasing need of energy and the increasing share of renewables in electric power generation demands higher flexibility in the operation of conventional power plants. Turbo generators have to face higher stress during operation without consuming additional life time. For the first time in a shop test a new generator design was extensively evaluated by using about 250 fibre optic sensors - mostly new developed - to control temperature, strain, movement and vibration.

  8. Excessive acquisition in hoarding.

    PubMed

    Frost, Randy O; Tolin, David F; Steketee, Gail; Fitch, Kristin E; Selbo-Bruns, Alexandra

    2009-06-01

    Compulsive hoarding (the acquisition of and failure to discard large numbers of possessions) is associated with substantial health risk, impairment, and economic burden. However, little research has examined separate components of this definition, particularly excessive acquisition. The present study examined acquisition in hoarding. Participants, 878 self-identified with hoarding and 665 family informants (not matched to hoarding participants), completed an Internet survey. Among hoarding participants who met criteria for clinically significant hoarding, 61% met criteria for a diagnosis of compulsive buying and approximately 85% reported excessive acquisition. Family informants indicated that nearly 95% exhibited excessive acquisition. Those who acquired excessively had more severe hoarding; their hoarding had an earlier onset and resulted in more psychiatric work impairment days; and they experienced more symptoms of obsessive-compulsive disorder, depression, and anxiety. Two forms of excessive acquisition (buying and free things) each contributed independent variance in the prediction of hoarding severity and related symptoms.

  9. Aerodynamic Design and Numerical Analysis of Supersonic Turbine for Turbo Pump

    NASA Astrophysics Data System (ADS)

    Fu, Chao; Zou, Zhengping; Kong, Qingguo; Cheng, Honggui; Zhang, Weihao

    2016-09-01

    Supersonic turbine is widely used in the turbo pump of modern rocket. A preliminary design method for supersonic turbine has been developed considering the coupling effects of turbine and nozzle. Numerical simulation has been proceeded to validate the feasibility of the design method. As the strong shockwave reflected on the mixing plane, additional numerical simulated error would be produced by the mixing plane model in the steady CFD. So unsteady CFD is employed to investigate the aerodynamic performance of the turbine and flow field in passage. Results showed that the preliminary design method developed in this paper is suitable for designing supersonic turbine. This periodical variation of complex shockwave system influences the development of secondary flow, wake and shock-boundary layer interaction, which obviously affect the secondary loss in vane passage. The periodical variation also influences the strength of reflecting shockwave, which affects the profile loss in vane passage. Besides, high circumferential velocity at vane outlet and short blade lead to high radial pressure gradient, which makes the low kinetic energy fluid moves towards hub region and produces additional loss.

  10. Preliminary thermodynamic study for an efficient turbo-blower external combustion Rankine cycle

    NASA Astrophysics Data System (ADS)

    Romero Gómez, Manuel; Romero Gómez, Javier; Ferreiro Garcia, Ramón; Baaliña Insua, Álvaro

    2014-08-01

    This research paper presents a preliminary thermodynamic study of an innovative power plant operating under a Rankine cycle fed by an external combustion system with turbo-blower (TB). The power plant comprises an external combustion system for natural gas, where the combustion gases yield their thermal energy, through a heat exchanger, to a carbon dioxide Rankine cycle operating under supercritical conditions and with quasi-critical condensation. The TB exploits the energy from the pressurised exhaust gases for compressing the combustion air. The study is focused on the comparison of the combustion system's conventional technology with that of the proposed. An energy analysis is carried out and the effect of the flue gas pressure on the efficiency and on the heat transfer in the heat exchanger is studied. The coupling of the TB results in an increase in efficiency and of the convection coefficient of the flue gas with pressure, favouring a reduced volume of the heat exchanger. The proposed innovative system achieves increases in efficiency of around 12 % as well as a decrease in the heat exchanger volume of 3/5 compared with the conventional technology without TB.

  11. Software Acquisition Program Dynamics

    DTIC Science & Technology

    2011-10-24

    acquisition and development of software-reliant systems . Novak has more than 25 years of experience with real-time embedded software product development...Problem Poor acquisition program performance inhibits military performance by depriving the warfighter of critical systems to achieve mission...objectives • Delayed systems withhold needed capabilities • Wasted resources drain funding needed for new systems Acquisitions fail for both technical

  12. FTMP data acquisition environment

    NASA Technical Reports Server (NTRS)

    Padilla, Peter A.

    1988-01-01

    The Fault-Tolerant Multi-Processing (FTMP) test-bed data acquisition environment is described. The performance of two data acquisition devices available in the test environment are estimated and compared. These estimated data rates are used as measures of the devices' capabilities. A new data acquisition device was developed and added to the FTMP environment. This path increases the data rate available by approximately a factor of 8, to 379 KW/S, while simplifying the experiment development process.

  13. Streamlined acquisition handbook

    NASA Technical Reports Server (NTRS)

    1990-01-01

    NASA has always placed great emphasis on the acquisition process, recognizing it as among its most important activities. This handbook is intended to facilitate the application of streamlined acquisition procedures. The development of these procedures reflects the efforts of an action group composed of NASA Headquarters and center acquisition professionals. It is the intent to accomplish the real change in the acquisition process as a result of this effort. An important part of streamlining the acquisition process is a commitment by the people involved in the process to accomplishing acquisition activities quickly and with high quality. Too often we continue to accomplish work in 'the same old way' without considering available alternatives which would require no changes to regulations, approvals from Headquarters, or waivers of required practice. Similarly, we must be sensitive to schedule opportunities throughout the acquisition cycle, not just once the purchase request arrives at the procurement office. Techniques that have been identified as ways of reducing acquisition lead time while maintaining high quality in our acquisition process are presented.

  14. Measurement and control system for cryogenic helium gas bearing turbo-expander experimental platform based on Siemens PLC S7-300

    NASA Astrophysics Data System (ADS)

    Li, J.; Xiong, L. Y.; Peng, N.; Dong, B.; Wang, P.; Liu, L. Q.

    2014-01-01

    An experimental platform for cryogenic Helium gas bearing turbo-expanders is established at the Technical Institute of Physics and Chemistry, Chinese Academy of Sciences. This turbo-expander experimental platform is designed for performance testing and experimental research on Helium turbo-expanders with different sizes from the liquid hydrogen temperature to the room temperature region. A measurement and control system based on Siemens PLC S7-300 for this turbo-expander experimental platform is developed. Proper sensors are selected to measure such parameters as temperature, pressure, rotation speed and air flow rate. All the collected data to be processed are transformed and transmitted to S7-300 CPU. Siemens S7-300 series PLC CPU315-2PN/DP is as master station and two sets of ET200M DP remote expand I/O is as slave station. Profibus-DP field communication is established between master station and slave stations. The upper computer Human Machine Interface (HMI) is compiled using Siemens configuration software WinCC V6.2. The upper computer communicates with PLC by means of industrial Ethernet. Centralized monitoring and distributed control is achieved. Experimental results show that this measurement and control system has fulfilled the test requirement for the turbo-expander experimental platform.

  15. Measurement and control system for cryogenic helium gas bearing turbo-expander experimental platform based on Siemens PLC S7-300

    SciTech Connect

    Li, J.; Xiong, L. Y.; Peng, N.; Dong, B.; Liu, L. Q.; Wang, P.

    2014-01-29

    An experimental platform for cryogenic Helium gas bearing turbo-expanders is established at the Technical Institute of Physics and Chemistry, Chinese Academy of Sciences. This turbo-expander experimental platform is designed for performance testing and experimental research on Helium turbo-expanders with different sizes from the liquid hydrogen temperature to the room temperature region. A measurement and control system based on Siemens PLC S7-300 for this turbo-expander experimental platform is developed. Proper sensors are selected to measure such parameters as temperature, pressure, rotation speed and air flow rate. All the collected data to be processed are transformed and transmitted to S7-300 CPU. Siemens S7-300 series PLC CPU315-2PN/DP is as master station and two sets of ET200M DP remote expand I/O is as slave station. Profibus-DP field communication is established between master station and slave stations. The upper computer Human Machine Interface (HMI) is compiled using Siemens configuration software WinCC V6.2. The upper computer communicates with PLC by means of industrial Ethernet. Centralized monitoring and distributed control is achieved. Experimental results show that this measurement and control system has fulfilled the test requirement for the turbo-expander experimental platform.

  16. Coring Sample Acquisition Tool

    NASA Technical Reports Server (NTRS)

    Haddad, Nicolas E.; Murray, Saben D.; Walkemeyer, Phillip E.; Badescu, Mircea; Sherrit, Stewart; Bao, Xiaoqi; Kriechbaum, Kristopher L.; Richardson, Megan; Klein, Kerry J.

    2012-01-01

    A sample acquisition tool (SAT) has been developed that can be used autonomously to sample drill and capture rock cores. The tool is designed to accommodate core transfer using a sample tube to the IMSAH (integrated Mars sample acquisition and handling) SHEC (sample handling, encapsulation, and containerization) without ever touching the pristine core sample in the transfer process.

  17. Turbo Equalization Scheme between Partial Response Maximum Likelihood Detector and Viterbi Decoder for 2/4 Modulation Code in Holographic Data Storage Systems

    NASA Astrophysics Data System (ADS)

    Kong, Gyuyeol; Choi, Sooyong

    2012-08-01

    A turbo equalization scheme for holographic data storage (HDS) systems is proposed. The proposed turbo equalization procedure is conducted between a one-dimensional (1D) partial response maximum likelihood (PRML) detector and the joint Viterbi decoder by exchanging a priori and extrinsic information. In the joint Viterbi decoder, the modulation and convolutional decoding is performed simultaneously by mapping a 2/4 modulation symbol onto the trellis of the convolutional code to reduce the complexity of the decoding procedure and improve the decoding capability for the iterative equalization and decoding. In addition, since the channel model is described as the two-dimensional convolution in HDS systems, the 1D PRML detector is performed in the vertical direction and the joint Viterbi decoder is performed in the horizontal direction to maximize the performance gains. The simulation result shows that the proposed turbo equalization scheme has the better bit error rate performances as the number of iterations increases.

  18. CFD Study of Turbo-Ramjet Interactions in Hypersonic Airbreathing Propulsion System

    NASA Technical Reports Server (NTRS)

    Chang, Ing; Hunter, Louis G.

    1996-01-01

    Advanced airbreathing propulsion systems used in Mach 4-6 mission scenarios, usually involve turbo-ramjet configurations. As the engines transition from turbojet to ramjet, there is an operational envelope where both engines operate simultaneously. In the first phase of our study, an over/under nozzle configuration was analyzed. The two plumes from the turbojet and ramjet interact at the end of a common 2-D cowl, where they both reach an approximate Mach 3.0 condition and then jointly expand to Mach 3.6 at the common nozzle exit plane. For the problem analyzed, the turbojet engine operates at a higher nozzle pressure ratio than the ramjet, causes the turbojet plume overpowers the ramjet plume, deflecting it approximately 12 degrees downward and in turn the turbojet plume is deflected 6 degrees upward. In the process, shocks were formed at the deflections and a shear layer formed at the confluence of the two jets. This particular case was experimentally tested and the data were used to compare with a computational fluid dynamics (CFD) study using the PARC2D code. The CFD results were in good agreement with both static pressure distributions on the cowl separator and on nozzle walls. The thrust coefficients were also in reasonable agreement. In addition, inviscid relationships were developed around the confluence point, where the two exhaust jets meet, and these results compared favorably with the CFD results. In the second phase of our study, a 3-D CFD solution was generated to compare with the 2-D solution. The major difference between the 2-D and 3-D solutions was the interaction of the shock waves, generated by the plume interactions, on the sidewall. When a shock wave interacts with a sidewall and sidewall boundary layer, it is called a glancing shock sidewall interaction. These interactions entrain boundary layer flow down the shockline into a vortical flow pattern. The 3-D plots show the streamlines being entrained down the shockline. The pressure of the flow

  19. A Simple Tight Bound on Error Probability of Block Codes with Application to Turbo Codes

    NASA Astrophysics Data System (ADS)

    Divsalar, D.

    1999-07-01

    A simple bound on the probability of decoding error for block codes is derived in closed form. This bound is based on the bounding techniques developed by Gallager. We obtained an upper bound both on the word-error probability and the bit-error probability of block codes. The bound is simple, since it does not require any integration or optimization in its final version. The bound is tight since it works for signal-to-noise ratios (SNRs) very close to the Shannon capacity limit. The bound uses only the weight distribution of the code. The bound for nonrandom codes is tighter than the original Gallager bound and its new versions derived by Sason and Shamai and by Viterbi and Viterbi. It also is tighter than the recent simpler bound by Viterbi and Viterbi and simpler than the bound by Duman and Salehi, which requires two-parameter optimization. For long blocks, it competes well with more complex bounds that involve integration and parameter optimization, such as the tangential sphere bound by Poltyrev, elaborated by Sason and Shamai, and investigated by Viterbi and Viterbi, and the geometry bound by Dolinar, Ekroot, and Pollara. We also obtained a closed-form expression for the minimum SNR threshold that can serve as a tight upper bound on maximum-likelihood capacity of nonrandom codes. We also have shown that this minimum SNR threshold of our bound is the same as for the tangential sphere bound of Poltyrev. We applied this simple bound to turbo-like codes.

  20. Vehicle performance optimization utilizing the air turbo-ramjet propulsion system: Methodology development and applications

    NASA Astrophysics Data System (ADS)

    Christensen, Kirk Le

    The ATR (Air TurboRocket) is an air breathing propulsion system in which the turbocompressor turbine is powered by a hot drive gas which is generated independently of the air flow through the compressor. The ATR has a lower specific impulse (Isp) and higher thrust compared to a similar size turbojet but a lower thrust and higher Isp compared to similar size solid rocket motor (SRM). This work defines the benefits of ATR propulsion for tactical vehicles. ATR simulation codes were developed to support analysis of hypothetical ATR powered vehicles. Both turbojet powered and SRM powered vehicles were also evaluated against range and time of flight as the major evaluation criteria. This analysis required the use of an existing turbojet code, a solid rocket motor (SRM) model, an aerodynamics predictor code (DATCOM) and a two dimensional, flat earth trajectory analysis code (ZTRAJ). Two weight class vehicles (800 and 3500 lbsbm) launched at Mach 0.9 and 10000 feet altitude were evaluated as well as a low Mach (0.1) launch of the 800 lbsbm class vehicle. These vehicles, with the three propulsion system options, required nine vehicle/trajectory analyses. The results of these analyses show that only the ATR powered vehicle is able to simultaneously meet minimum range and maximum flight time requirements. The SRM powered vehicle (because of its low Isp) only achieves about 50% of the range of the ATR powered vehicle. The turbojet powered vehicle (because of its low thrust) required more than 30% of the flight time required by the ATR powered vehicle for the same range.

  1. Computer simulation of the heavy-duty turbo-compounded diesel cycle for studies of engine efficiency and performance

    NASA Technical Reports Server (NTRS)

    Assanis, D. N.; Ekchian, J. A.; Heywood, J. B.; Replogle, K. K.

    1984-01-01

    Reductions in heat loss at appropriate points in the diesel engine which result in substantially increased exhaust enthalpy were shown. The concepts for this increased enthalpy are the turbocharged, turbocompounded diesel engine cycle. A computer simulation of the heavy duty turbocharged turbo-compounded diesel engine system was undertaken. This allows the definition of the tradeoffs which are associated with the introduction of ceramic materials in various parts of the total engine system, and the study of system optimization. The basic assumptions and the mathematical relationships used in the simulation of the model engine are described.

  2. Human target acquisition performance

    NASA Astrophysics Data System (ADS)

    Teaney, Brian P.; Du Bosq, Todd W.; Reynolds, Joseph P.; Thompson, Roger; Aghera, Sameer; Moyer, Steven K.; Flug, Eric; Espinola, Richard; Hixson, Jonathan

    2012-06-01

    The battlefield has shifted from armored vehicles to armed insurgents. Target acquisition (identification, recognition, and detection) range performance involving humans as targets is vital for modern warfare. The acquisition and neutralization of armed insurgents while at the same time minimizing fratricide and civilian casualties is a mounting concern. U.S. Army RDECOM CERDEC NVESD has conducted many experiments involving human targets for infrared and reflective band sensors. The target sets include human activities, hand-held objects, uniforms & armament, and other tactically relevant targets. This paper will define a set of standard task difficulty values for identification and recognition associated with human target acquisition performance.

  3. Interactive knowledge acquisition tools

    NASA Technical Reports Server (NTRS)

    Dudziak, Martin J.; Feinstein, Jerald L.

    1987-01-01

    The problems of designing practical tools to aid the knowledge engineer and general applications used in performing knowledge acquisition tasks are discussed. A particular approach was developed for the class of knowledge acquisition problem characterized by situations where acquisition and transformation of domain expertise are often bottlenecks in systems development. An explanation is given on how the tool and underlying software engineering principles can be extended to provide a flexible set of tools that allow the application specialist to build highly customized knowledge-based applications.

  4. Acquisitions for Area Programs

    ERIC Educational Resources Information Center

    Stevens, Robert D.

    1970-01-01

    Common policies, practices, and trends in acquisitions in the complex field of area studies, including the weak structure of the book trade, the lack of bibliographic control, and current cooperative efforts. (JS)

  5. Data acquisition system

    DOEpatents

    Shapiro, Stephen L.; Mani, Sudhindra; Atlas, Eugene L.; Cords, Dieter H. W.; Holbrook, Britt

    1997-01-01

    A data acquisition circuit for a particle detection system that allows for time tagging of particles detected by the system. The particle detection system screens out background noise and discriminate between hits from scattered and unscattered particles. The detection system can also be adapted to detect a wide variety of particle types. The detection system utilizes a particle detection pixel array, each pixel containing a back-biased PIN diode, and a data acquisition pixel array. Each pixel in the particle detection pixel array is in electrical contact with a pixel in the data acquisition pixel array. In response to a particle hit, the affected PIN diodes generate a current, which is detected by the corresponding data acquisition pixels. This current is integrated to produce a voltage across a capacitor, the voltage being related to the amount of energy deposited in the pixel by the particle. The current is also used to trigger a read of the pixel hit by the particle.

  6. Documentation and knowledge acquisition

    NASA Technical Reports Server (NTRS)

    Rochowiak, Daniel; Moseley, Warren

    1990-01-01

    Traditional approaches to knowledge acquisition have focused on interviews. An alternative focuses on the documentation associated with a domain. Adopting a documentation approach provides some advantages during familiarization. A knowledge management tool was constructed to gain these advantages.

  7. Army Acquisition Lessons Learned

    DTIC Science & Technology

    2014-10-01

    analysis on the lessons learned. Acquisition Lessons Learned Portal (ALLP) and Lessons Learned Collection CAALL has established the ALLP as the...PEOs) and their project offices, as well as the broader acquisition community. The primary function of the portal is to allow easy input and retrieval...download- able form that can be completed offline and then uploaded to the portal . This allows the form to be filled out and distrib- uted through

  8. Acquisition Support Program Overview

    DTIC Science & Technology

    2016-06-30

    Feedback from direct support and community learning improves ASP practices & SEI technologies © 2006 by Carnegie Mellon University page 6 ASP...the acquisition infrastructure throughout the DoD, Federal Agency and other acquirer communities . © 2006 by Carnegie Mellon University page 3...Seminars • Tailored learning via Acquisition Communities of Practice • Army, Navy, Air Force, Defense and Intel Agencies • Software Collaborator’s Network

  9. Multispectral 3D phase-encoded turbo spin-echo for imaging near metal: Limitations and possibilities demonstrated by simulations and phantom experiments.

    PubMed

    van Gorp, Jetse S; Nizak, Razmara; Bouwman, Job G; Saris, Daniël B F; Seevinck, Peter R

    2017-01-25

    To see improvements in the imaging performance near biomaterial implants we assessed a multispectral fully phase-encoded turbo spin-echo (ms3D-PE-TSE) sequence for artifact reduction capabilities and scan time efficiency in simulation and phantom experiments. For this purpose, ms3D-PE-TSE and ms3D-TSE sequences were implemented to obtain multispectral images (±20kHz) of a cobalt-chromium (CoCr) knee implant embedded in agarose. In addition, a knee implant computer model and the acquired ms3D-PE-TSE images were used to investigate the possibilities for scan time acceleration using field-of-view (FOV) reduction for off-resonance frequency bins and compressed sensing reconstructions of undersampled data. Both acceleration methods were combined to acquire a +10kHz frequency bin in a second experiment. The obtained ms3D-PE-TSE images showed no susceptibility related artifacts, while ms3D-TSE images suffered from hyper-intensity artifacts. The limitations of ms3D-TSE were apparent in the far off-resonance regions (±[10-20]kHz) located close to the implant. The scan time calculations showed that ms3D-PE-TSE can be applied in a clinically relevant timeframe (~12min), when omitting the three central frequency bins. The feasibility of CS acceleration for ms3D-PE-TSE was demonstrated using retrospective reconstructions before combining CS and rFOV imaging to decrease the scan time for the +10kHz frequency bin from ~10.9min to ~3.5min, while also increasing the spatial resolution fourfold. The temporally resolved signal of ms3D-PE-TSE proved to be useful to decrease the intensity ripples after sum-of-squares reconstructions and increase the signal-to-noise ratio. The presented results suggest that the scan time limitations of ms3D-PE-TSE can be sufficiently addressed when focusing on signal acquisitions in the direct vicinity of metal implants. Because these regions cannot be measured with existing multispectral methods, the presented ms3D-PE-TSE method may enable the

  10. Analysis and Simulation on the Effect of Rotor Interturn Short Circuit on Magnetic Flux Density of Turbo-Generator

    NASA Astrophysics Data System (ADS)

    He, Yu-Ling; Ke, Meng-Qiang; Tang, Gui-Ji; Jiang, Hong-Chun; Yuan, Xing-Hua

    2016-09-01

    The intent of this paper is to investigate the effect of the interturn short circuit fault (ISCF) in rotor on the magnetic flux density (MFD) of turbo-generator. Different from other studies, this work not only pays attention to the influence of the faulty degrees on the general magnetic field, but also investigates the effect of the short circuit positions on the harmonic components of MFD. The theoretical analysis and the digital simulation through the FEM software Ansoft are performed for a QSFN-600-2YHG turbo-generator. Several significant formulas and conclusions drawn from the analysis and the simulation results are obtained to indicate the relation between the harmonic amplitude of the MFD and the faulty degree (via nm, the number of the short circuit turns), and the relation between the MFD harmonic amplitude and the faulty position (via αr, the angle of the two slots in which the interturn short circuit occurs). Also, the developing tendency of the general magnetic field intensity, the distribution of the magnetic flux lines, and the peak-to-peak value of MFD are presented.

  11. Detection of renal ischemic lesions using Gd-DTPA enhanced turbo FLASH MRI: Experimental and clinical results

    SciTech Connect

    Vosshenrich, R.; Fischer, U.; Funke, M.; Kopka, L.; Grabbe, E.

    1996-03-01

    Our goal was to investigate the role of Gd-DTPA-enhanced dynamic MRI in the evaluation of renal ischemic lesions. With a turbo FLASH sequence before and after injection of Gd-DTPA, nine foxhound dogs after 60-120 min of renal ischemia underwent MR examination. In addition, five patients with a tumor in a solitary kidney were examined before and after nephron-sparing renal surgery to evaluate renal perfusion and function. The experimental and clinical findings were correlated with conventional measurements of kidney function and with histological findings. Complete renal ischemia leads to a poor corticomedullary differentiation in Gd-DTPA-enhanced turbo FLASH MRI. The signal-intensity-versus-time plots of kidneys with significant postischemic changes show a less steep increase of signal intensity in the cortex and a steeper increase of signal intensity in the medulla than those of normal kidneys. Dynamic MRI demonstrate renal morphology and reflect the functional status of the renal vasculature. 21 refs., 8 figs., 1 tab.

  12. Prospective Study of Plasmodium vivax Malaria Recurrence after Radical Treatment with a Chloroquine-Primaquine Standard Regimen in Turbo, Colombia

    PubMed Central

    Blair, Silvia; Akinyi Okoth, Sheila; Udhayakumar, Venkatachalam; Marcet, Paula L.; Escalante, Ananias A.; Alexander, Neal; Rojas, Carlos

    2016-01-01

    Plasmodium vivax recurrences help maintain malaria transmission. They are caused by recrudescence, reinfection, or relapse, which are not easily differentiated. A longitudinal observational study took place in Turbo municipality, Colombia. Participants with uncomplicated P. vivax infection received supervised treatment concomitantly with 25 mg/kg chloroquine and 0.25 mg/kg/day primaquine for 14 days. Incidence of recurrence was assessed over 180 days. Samples were genotyped, and origins of recurrences were established. A total of 134 participants were enrolled between February 2012 and July 2013, and 87 were followed for 180 days, during which 29 recurrences were detected. The cumulative incidence of first recurrence was 24.1% (21/87) (95% confidence interval [CI], 14.6 to 33.7%), and 86% (18/21) of these events occurred between days 51 and 110. High genetic diversity of P. vivax strains was found, and 12.5% (16/128) of the infections were polyclonal. Among detected recurrences, 93.1% (27/29) of strains were genotyped as genetically identical to the strain from the previous infection episode, and 65.5% (19/29) of infections were classified as relapses. Our results indicate that there is a high incidence of P. vivax malaria recurrence after treatment in Turbo municipality, Colombia, and that a large majority of these episodes are likely relapses from the previous infection. We attribute this to the primaquine regimen currently used in Colombia, which may be insufficient to eliminate hypnozoites. PMID:27185794

  13. Performance enhancement of MC-CDMA system through novel sensitive bit algorithm aided turbo multi user detection.

    PubMed

    Kumaravel, Rasadurai; Narayanaswamy, Kumaratharan

    2015-01-01

    Multi carrier code division multiple access (MC-CDMA) system is a promising multi carrier modulation (MCM) technique for high data rate wireless communication over frequency selective fading channels. MC-CDMA system is a combination of code division multiple access (CDMA) and orthogonal frequency division multiplexing (OFDM). The OFDM parts reduce multipath fading and inter symbol interference (ISI) and the CDMA part increases spectrum utilization. Advantages of this technique are its robustness in case of multipath propagation and improve security with the minimize ISI. Nevertheless, due to the loss of orthogonality at the receiver in a mobile environment, the multiple access interference (MAI) appears. The MAI is one of the factors that degrade the bit error rate (BER) performance of MC-CDMA system. The multiuser detection (MUD) and turbo coding are the two dominant techniques for enhancing the performance of the MC-CDMA systems in terms of BER as a solution of overcome to MAI effects. In this paper a low complexity iterative soft sensitive bits algorithm (SBA) aided logarithmic-Maximum a-Posteriori algorithm (Log MAP) based turbo MUD is proposed. Simulation results show that the proposed method provides better BER performance with low complexity decoding, by mitigating the detrimental effects of MAI.

  14. Assessment of error propagation in ultraspectral sounder data via JPEG2000 compression and turbo coding

    NASA Astrophysics Data System (ADS)

    Olsen, Donald P.; Wang, Charles C.; Sklar, Dean; Huang, Bormin; Ahuja, Alok

    2005-08-01

    Research has been undertaken to examine the robustness of JPEG2000 when corrupted by transmission bit errors in a satellite data stream. Contemporary and future ultraspectral sounders such as Atmospheric Infrared Sounder (AIRS), Cross-track Infrared Sounder (CrIS), Infrared Atmospheric Sounding Interferometer (IASI), Geosynchronous Imaging Fourier Transform Spectrometer (GIFTS), and Hyperspectral Environmental Suite (HES) generate a large volume of three-dimensional data. Hence, compression of ultraspectral sounder data will facilitate data transmission and archiving. There is a need for lossless or near-lossless compression of ultraspectral sounder data to avoid potential retrieval degradation of geophysical parameters due to lossy compression. This paper investigates the simulated error propagation in AIRS ultraspectral sounder data with advanced source and channel coding in a satellite data stream. The source coding is done via JPEG2000, the latest International Organization for Standardization (ISO)/International Telecommunication Union (ITU) standard for image compression. After JPEG2000 compression the AIRS ultraspectral sounder data is then error correction encoded using a rate 0.954 turbo product code (TPC) for channel error control. Experimental results of error patterns on both channel and source decoding are presented. The error propagation effects are curbed via the block-based protection mechanism in the JPEG2000 codec as well as memory characteristics of the forward error correction (FEC) scheme to contain decoding errors within received blocks. A single nonheader bit error in a source code block tends to contaminate the bits until the end of the source code block before the inverse discrete wavelet transform (IDWT), and those erroneous bits propagate even further after the IDWT. Furthermore, a single header bit error may result in the corruption of almost the entire decompressed granule. JPEG2000 appears vulnerable to bit errors in a noisy channel of

  15. Turbo methanol extract inhibits bone resorption through regulation of T cell function.

    PubMed

    Balakrishnan, Babita; Indap, Madhavi M; Singh, Surya P; Krishna, C Murali; Chiplunkar, Shubhada V

    2014-01-01

    Marine organisms have bioactive potential which has tremendous pharmaceutical promise. Emerging evidence highlights the importance of the interplay between bone and the immune system of which T lymphocytes and their product act as key regulators of bone resorption. In the present investigation we have analyzed the anti-osteoporotic effect of turbo methanol extract (TME) in the reversal of bone resoprtion. Forty-two female Swiss albino mice were used and randomly assigned into sham-operated group (sham) and six ovariectomized (OVX) subgroups, i.e. OVX with vehicle (OVX) that received daily oral administration of water ad libitum; OVX with estradiol (2mg/kg/day); and OVX with different doses of TME i.e. TME 100mg/kg, TME 50mg/kg, TME 25mg/kg and TME 12.5mg/kg. Oral administration of TME or estradiol started on the second week after ovariectomy for a period of 4weeks. We observed that the administration of TME increased the trabeculation in tibia and reduced the atrophy in the uterus. TME significantly decreased the serum alkaline phosphatase (ALP) and acid phosphatase (ACP) activity in OVX mice. Micro CT analysis revealed that the TME administration preserved the bone volume, connectivity density, trabecular number, trabecular thickness and trabecular separation in OVX mice. Bone mineralization was measured in different groups of mice by Raman spectroscopy. Reversal of bone resorption was observed in TME treated group of mice. To further investigate the mechanism of action of TME, we analyzed the T lymphocyte proliferation and profiles of cytokine TNFα and sRANKL in TME treated ovariectomized mice. Decrease in the elevation of T cell subsets was observed after the supplementation with TME. The extract significantly lowered the T cell proliferation responses to mitogens, phorbol 12-myristate 13-acetate (PMA) and ionomycin (Io) and phytohemagglutinin (PHA). A marked reduction in TNFα and sRANKL secretion in serum and TNFα in cell free supernatants of activated T

  16. 75 FR 14057 - Federal Acquisition Regulation; Federal Acquisition Circular 2005-40; Introduction

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-23

    ... Federal Acquisition Regulation; Federal Acquisition Circular 2005-40: Introduction, Small Entity... Acquisition Regulation; Federal Acquisition Circular 2005-40; Introduction AGENCIES: Department of Defense...

  17. Coordinating Council. Seventh Meeting: Acquisitions

    NASA Technical Reports Server (NTRS)

    1992-01-01

    The theme for this NASA Scientific and Technical Information Program Coordinating Council meeting was Acquisitions. In addition to NASA and the NASA Center for AeroSpace Information (CASI) presentations, the report contains fairly lengthy visuals about acquisitions at the Defense Technical Information Center. CASI's acquisitions program and CASI's proactive acquisitions activity were described. There was a presentation on the document evaluation process at CASI. A talk about open literature scope and coverage at the American Institute of Aeronautics and Astronautics was also given. An overview of the STI Program's Acquisitions Experts Committee was given next. Finally acquisitions initiatives of the NASA STI program were presented.

  18. A study of the effects of disk flexibility on the rotordynamics of the space shuttle main engine turbo-pumps

    NASA Technical Reports Server (NTRS)

    Flowers, George T.

    1989-01-01

    Rotor dynamical analyses are typically performed using rigid disk models. Studies of rotor models in which the effects of disk flexibility were included indicate that is may be an important effect for many systems. This issue is addressed with respect to the Space Shuttle Main Engine high pressure turbo-pumps. Finite element analyses have been performed for a simplified free-free flexible disk rotor model and the modes and frequencies compared to those of a rigid disk model. The simple model was then extended to a more sophisticated HPTOP rotor model and similar results were observed. Equations were developed that are suitable for modifying the current rotordynamical analysis program to account for disk flexibility. Some conclusions are drawn from the results of this work as to the importance of disk flexibility on the HPTOP rotordynamics and some recommendations are given for follow-up research in this area.

  19. Feasibility study of air-breathing turbo-engines for horizontal take-off and landing space plane

    SciTech Connect

    Minoda, M.; Sakata, K.; Tamaki, T.; Saitoh, T.; Yasuda, A.

    1989-01-01

    Various concepts of air-breathing engines (ABEs) that could be used for a horizontal take-off and landing SSTO vehicle are investigated. The performances (with respect to thrust and the specific fuel consumption) of turboengines based on various technologies, including a turbojet with and without afterburner (TJ), turboramjet, and air-turbo-ram jet engines are compared. The mission capabilities of these ABEs for SSTO and TSTO vehicles is examined in terms of the ratio of the effective remaining weight (i.e., the weight on the orbit) to the take-off gross weight, using two-dimensional flight analysis. It was found that the dry TJ with the turbine inlet temperature 2000 C is one of the most promising candidates for the propulsion system of the SSTO vehicle, because of its small weight and high specific impulse. 6 refs.

  20. Data Acquisition Backend

    SciTech Connect

    Britton Jr., Charles L.; Ezell, N. Dianne Bull; Roberts, Michael

    2013-10-01

    This document is intended to summarize the development and testing of the data acquisition module portion of the Johnson Noise Thermometry (JNT) system developed at ORNL. The proposed system has been presented in an earlier report [1]. A more extensive project background including the project rationale is available in the initial project report [2].

  1. Surviving mergers & acquisitions.

    PubMed

    Dixon, Diane L

    2002-01-01

    Mergers and acquisitions are never easy to implement. The health care landscape is a minefield of failed mergers and uneasy alliances generating great turmoil and pain. But some mergers have been successful, creating health systems that benefit the communities they serve. Five prominent leaders offer their advice on minimizing the difficulties of M&As.

  2. Autonomous Robot Skill Acquisition

    DTIC Science & Technology

    2011-05-01

    Research. ix ABSTRACT AUTONOMOUS ROBOT SKILL ACQUISITION MAY 2011 GEORGE DIMITRI KONIDARIS B.Sc., UNIVERSITY OF THE WITWATERSRAND B.Sc. Hons., UNIVERSITY...OF THE WITWATERSRAND M.Sc., UNIVERSITY OF EDINBURGH Ph.D., UNIVERSITY OF MASSACHUSETTS AMHERST Directed by: Professor Andrew G. Barto Among the most

  3. Acquisitions List No. 43.

    ERIC Educational Resources Information Center

    Planned Parenthood--World Population, New York, NY. Katherine Dexter McCormick Library.

    The "Acquisitions List" of demographic books and articles is issued every two months by the Katharine Dexter McCormick Library. Divided into two parts, the first contains a list of books most recently acquired by the Library, each one annotated and also marked with the Library call number. The second part consists of a list of annotated articles,…

  4. Acquisitions List No. 42.

    ERIC Educational Resources Information Center

    Planned Parenthood--World Population, New York, NY. Katherine Dexter McCormick Library.

    The "Acquisitions List" of demographic books and articles is issued every two months by the Katharine Dexter McCormick Library. Divided into two parts, the first contains a list of books most recently acquired by the Library, each one annotated and also marked with the Library call number. The second part consists of a list of annotated articles,…

  5. Telecommunications and data acquisition

    NASA Technical Reports Server (NTRS)

    Renzetti, N. A. (Editor)

    1981-01-01

    Deep Space Network progress in flight project support, tracking and data acquisition research and technology, network engineering, hardware and software implementation, and operations is reported. In addition, developments in Earth based radio technology as applied to geodynamics, astrophysics, and the radio search for extraterrestrial intelligence are reported.

  6. Acquisition of Comparison Constructions

    ERIC Educational Resources Information Center

    Hohaus, Vera; Tiemann, Sonja; Beck, Sigrid

    2014-01-01

    This article presents a study on the time course of the acquisition of comparison constructions. The order in which comparison constructions (comparatives, measure phrases, superlatives, degree questions, etc.) show up in English- and German-learning children's spontaneous speech is quite fixed. It is shown to be insufficiently determined by…

  7. Image Acquisition Context

    PubMed Central

    Bidgood, W. Dean; Bray, Bruce; Brown, Nicolas; Mori, Angelo Rossi; Spackman, Kent A.; Golichowski, Alan; Jones, Robert H.; Korman, Louis; Dove, Brent; Hildebrand, Lloyd; Berg, Michael

    1999-01-01

    Objective: To support clinically relevant indexing of biomedical images and image-related information based on the attributes of image acquisition procedures and the judgments (observations) expressed by observers in the process of image interpretation. Design: The authors introduce the notion of “image acquisition context,” the set of attributes that describe image acquisition procedures, and present a standards-based strategy for utilizing the attributes of image acquisition context as indexing and retrieval keys for digital image libraries. Methods: The authors' indexing strategy is based on an interdependent message/terminology architecture that combines the Digital Imaging and Communication in Medicine (DICOM) standard, the SNOMED (Systematized Nomenclature of Human and Veterinary Medicine) vocabulary, and the SNOMED DICOM microglossary. The SNOMED DICOM microglossary provides context-dependent mapping of terminology to DICOM data elements. Results: The capability of embedding standard coded descriptors in DICOM image headers and image-interpretation reports improves the potential for selective retrieval of image-related information. This favorably affects information management in digital libraries. PMID:9925229

  8. 78 FR 37164 - Land Acquisitions: Appeals of Land Acquisition Decisions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-20

    ...; Docket ID: BIA-2013-0005] RIN 1076-AF15 Land Acquisitions: Appeals of Land Acquisition Decisions AGENCY... applications to acquire land in trust under 25 CFR part 151. This document makes corrections to the...

  9. A Lagrangian parcel based mixing plane method for calculating water based mixed phase particle flows in turbo-machinery

    NASA Astrophysics Data System (ADS)

    Bidwell, Colin S.

    2015-05-01

    A method for calculating particle transport through turbo-machinery using the mixing plane analogy was developed and used to analyze the energy efficient engine . This method allows the prediction of temperature and phase change of water based particles along their path and the impingement efficiency and particle impact property data on various components in the engine. This methodology was incorporated into the LEWICE3D V3.5 software. The method was used to predict particle transport in the low pressure compressor of the . The was developed by NASA and GE in the early 1980s as a technology demonstrator and is representative of a modern high bypass turbofan engine. The flow field was calculated using the NASA Glenn ADPAC turbo-machinery flow solver. Computations were performed for a Mach 0.8 cruise condition at 11,887 m assuming a standard warm day for ice particle sizes of 5, 20 and 100 microns and a free stream particle concentration of . The impingement efficiency results showed that as particle size increased average impingement efficiencies and scoop factors increased for the various components. The particle analysis also showed that the amount of mass entering the inner core decreased with increased particle size because the larger particles were less able to negotiate the turn into the inner core due to particle inertia. The particle phase change analysis results showed that the larger particles warmed less as they were transported through the low pressure compressor. Only the smallest 5 micron particles were warmed enough to produce melting with a maximum average melting fraction of 0.18. The results also showed an appreciable amount of particle sublimation and evaporation for the 5 micron particles entering the engine core (22.6 %).

  10. 48 CFR 7.401 - Acquisition considerations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Acquisition considerations. 7.401 Section 7.401 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION ACQUISITION PLANNING ACQUISITION PLANNING Equipment Lease or Purchase 7.401 Acquisition considerations....

  11. Single-shot observation of optical rogue waves in integrable turbulence using time microscopy

    PubMed Central

    Suret, Pierre; Koussaifi, Rebecca El; Tikan, Alexey; Evain, Clément; Randoux, Stéphane; Szwaj, Christophe; Bielawski, Serge

    2016-01-01

    Optical fibres are favourable tabletop laboratories to investigate both coherent and incoherent nonlinear waves. In particular, exact solutions of the one-dimensional nonlinear Schrödinger equation such as fundamental solitons or solitons on finite background can be generated by launching periodic, specifically designed coherent waves in optical fibres. It is an open fundamental question to know whether these coherent structures can emerge from the nonlinear propagation of random waves. However the typical sub-picosecond timescale prevented—up to now—time-resolved observations of the awaited dynamics. Here, we report temporal ‘snapshots' of random light using a specially designed ‘time-microscope'. Ultrafast structures having peak powers much larger than the average optical power are generated from the propagation of partially coherent waves in optical fibre and are recorded with 250 femtoseconds resolution. Our experiment demonstrates the central role played by ‘breather-like' structures such as the Peregrine soliton in the emergence of heavy-tailed statistics in integrable turbulence. PMID:27713416

  12. Single shot ultrafast dynamic ellipsometry (UDE) of laser-driven shocks in single crystal explosives

    SciTech Connect

    Whitley, Von H; Mcgrane, Shawn D; Moore, David S; Eakins, Dan E; Bolme, Cindy A

    2009-01-01

    We report on the first experiments to measure states in shocked energetic single crystals with dynamic ellipsometry. We demonstrate that these ellipsometric techniques can produce reasonable Hugoniot values using small amounts of crystalline RDX and PETN. Pressures, particle velocities and shock velocities obtained using shocked ellipsometry are comparable to those found using gas-gun flyer plates and molecular dynamics calculations. The adaptation of the technique from uniform thin films of polymers to thick non-perfect crystalline materials was a significant achievement. Correct sample preparation proved to be a crucial component. Through trial and error, we were able to resolve polishing issues, sample quality problems, birefringence effects and mounting difficulties that were not encountered using thin polymer films.

  13. Optical design of a multi-resolution, single-shot spectrograph

    NASA Astrophysics Data System (ADS)

    Hénault, François; Laurent, Florence

    2016-08-01

    Multi-object or integral field spectrographs today are recognized techniques for achieving simultaneous spectroscopic observations of different or extended sky objects with a high multiplex factor. In this communication is described a complementary approach for realizing similar measurements under different spectral resolutions at the same time. Herein is explained the basic principle of this new type of spectrometer, that is based on the utilization of an optical pupil slicer. An optical design inspired from an already studied instrument is then presented and commented for the sake of illustration. Technical issues about the pupil slicer and diffractive components are also discussed. We finally conclude on the potential advantages and drawbacks of the proposed system.

  14. Sequential single shot X-ray photon correlation spectroscopy at the SACLA free electron laser

    DOE PAGES

    Lehmkühler, Felix; Kwaśniewski, Paweł; Roseker, Wojciech; ...

    2015-11-27

    In this study, hard X-ray free electron lasers allow for the first time to access dynamics of condensed matter samples ranging from femtoseconds to several hundred seconds. In particular, the exceptional large transverse coherence of the X-ray pulses and the high time-averaged flux promises to reach time and length scales that have not been accessible up to now with storage ring based sources. However, due to the fluctuations originating from the stochastic nature of the self-amplified spontaneous emission (SASE) process the application of well established techniques such as X-ray photon correlation spectroscopy (XPCS) is challenging. Here we demonstrate a single-shotmore » based sequential XPCS study on a colloidal suspension with a relaxation time comparable to the SACLA free-electron laser pulse repetition rate. High quality correlation functions could be extracted without any indications for sample damage. This opens the way for systematic sequential XPCS experiments at FEL sources.« less

  15. Designing High-Fidelity Single-Shot Three-Qubit Gates: A Machine-Learning Approach

    NASA Astrophysics Data System (ADS)

    Zahedinejad, Ehsan; Ghosh, Joydip; Sanders, Barry C.

    2016-11-01

    Three-qubit quantum gates are key ingredients for quantum error correction and quantum-information processing. We generate quantum-control procedures to design three types of three-qubit gates, namely Toffoli, controlled-not-not, and Fredkin gates. The design procedures are applicable to a system comprising three nearest-neighbor-coupled superconducting artificial atoms. For each three-qubit gate, the numerical simulation of the proposed scheme achieves 99.9% fidelity, which is an accepted threshold fidelity for fault-tolerant quantum computing. We test our procedure in the presence of decoherence-induced noise and show its robustness against random external noise generated by the control electronics. The three-qubit gates are designed via the machine-learning algorithm called subspace-selective self-adaptive differential evolution.

  16. UV-Vis as quantification tool for solubilized lignin following a single-shot steam process.

    PubMed

    Lee, Roland A; Bédard, Charles; Berberi, Véronique; Beauchet, Romain; Lavoie, Jean-Michel

    2013-09-01

    In this short communication, UV/Vis was used as an analytical tool for the quantification of lignin concentrations in aqueous mediums. A significant correlation was determined between absorbance and concentration of lignin in solution. For this study, lignin was produced from different types of biomasses (willow, aspen, softwood, canary grass and hemp) using steam processes. Quantification was performed at 212, 225, 237, 270, 280 and 287 nm. UV-Vis quantification of lignin was found suitable for different types of biomass making this a timesaving analytical system that could lead to uses as Process Analytical Tool (PAT) in biorefineries utilizing steam processes or comparable approaches.

  17. Single-Shot Smartphone-Based Quantitative Phase Imaging Using a Distorted Grating

    PubMed Central

    Yang, Zhenyu; Zhan, Qiwen

    2016-01-01

    Blood testing has been used as an essential tool to diagnose diseases for decades. Recently, there has been a rapid developing trend in using Quantitative Phase Imaging (QPI) methods for blood cell screening. Compared to traditional blood testing techniques, QPI has the advantage of avoiding dyeing or staining the specimen, which may cause damage to the cells. However, most existing systems are bulky and costly, requiring experienced personnel to operate. This work demonstrates the integration of one QPI method onto a smartphone platform and the application of imaging red blood cells. The adopted QPI method is based on solving the Intensity Transport Equation (ITE) from two de-focused pupil images taken in one shot by the smartphone camera. The device demonstrates a system resolution of about 1 μm, and is ready to be used for 3D morphological study of red blood cells. PMID:27441837

  18. Kinobead and Single-Shot LC-MS Profiling Identifies Selective PKD Inhibitors.

    PubMed

    Golkowski, Martin; Vidadala, Rama Subba Rao; Lombard, Chloe K; Suh, Hyong Won; Maly, Dustin J; Ong, Shao-En

    2017-03-03

    ATP-competitive protein kinase inhibitors are important research tools and therapeutic agents. Because there are >500 human kinases that contain highly conserved active sites, the development of selective inhibitors is extremely challenging. Methods to rapidly and efficiently profile kinase inhibitor targets in cell lysates are urgently needed to discover selective compounds and to elucidate the mechanisms of action for polypharmacological inhibitors. Here, we describe a protocol for microgram-scale chemoproteomic profiling of ATP-competitive kinase inhibitors using kinobeads. We employed a gel-free in situ digestion protocol coupled to nanoflow liquid chromatography-mass spectrometry to profile ∼200 kinases in single analytical runs using as little as 5 μL of kinobeads and 300 μg of protein. With our kinobead reagents, we obtained broad coverage of the kinome, monitoring the relative expression levels of 312 kinases in a diverse panel of 11 cancer cell lines. Further, we profiled a set of pyrrolopyrimidine- and pyrazolopyrimidine-based kinase inhibitors in competition-binding experiments with label-free quantification, leading to the discovery of a novel selective and potent inhibitor of protein kinase D (PKD) 1, 2, and 3. Our protocol is useful for rapid and sensitive profiling of kinase expression levels and ATP-competitive kinase inhibitor selectivity in native proteomes.

  19. Phase noise in pulsed Doppler lidar and limitations on achievable single-shot velocity accuracy

    NASA Technical Reports Server (NTRS)

    Mcnicholl, P.; Alejandro, S.

    1992-01-01

    The smaller sampling volumes afforded by Doppler lidars compared to radars allows for spatial resolutions at and below some sheer and turbulence wind structure scale sizes. This has brought new emphasis on achieving the optimum product of wind velocity and range resolutions. Several recent studies have considered the effects of amplitude noise, reduction algorithms, and possible hardware related signal artifacts on obtainable velocity accuracy. We discuss here the limitation on this accuracy resulting from the incoherent nature and finite temporal extent of backscatter from aerosols. For a lidar return from a hard (or slab) target, the phase of the intermediate frequency (IF) signal is random and the total return energy fluctuates from shot to shot due to speckle; however, the offset from the transmitted frequency is determinable with an accuracy subject only to instrumental effects and the signal to noise ratio (SNR), the noise being determined by the LO power in the shot noise limited regime. This is not the case for a return from a media extending over a range on the order of or greater than the spatial extent of the transmitted pulse, such as from atmospheric aerosols. In this case, the phase of the IF signal will exhibit a temporal random walk like behavior. It will be uncorrelated over times greater than the pulse duration as the transmitted pulse samples non-overlapping volumes of scattering centers. Frequency analysis of the IF signal in a window similar to the transmitted pulse envelope will therefore show shot-to-shot frequency deviations on the order of the inverse pulse duration reflecting the random phase rate variations. Like speckle, these deviations arise from the incoherent nature of the scattering process and diminish if the IF signal is averaged over times greater than a single range resolution cell (here the pulse duration). Apart from limiting the high SNR performance of a Doppler lidar, this shot-to-shot variance in velocity estimates has a practical impact on lidar design parameters. In high SNR operation, for example, a lidar's efficiency in obtaining mean wind measurements is determined by its repetition rate and not pulse energy or average power. In addition, this variance puts a practical limit on the shot-to-shot hard target performance required of a lidar.

  20. Single shot extreme ultraviolet laser imaging of nanostructures with wavelength resolution

    SciTech Connect

    Jones, Juanita; Brewer, Courtney A.; Brizuela, Fernando; Wachulak, Przemyslaw; Martz, Dale H.; Chao, Weilun; Anderson, Erik H.; Attwood, David T.; Vinogradov, Alexander V.; Artyukov, Igor A.; Ponomareko, Alexander G.; Kondratenko, Valeriy V.; Marconi, Mario C.; Rocca, Jorge J.; Menoni, Carmen S.

    2008-01-07

    We have demonstrated near-wavelength resolution microscopy in the extreme ultraviolet. Images of 50 nm diameter nanotubes were obtained with a single {approx}1 ns duration pulse from a desk-top size 46.9 nm laser. We measured the modulation transfer function of the microscope for three different numerical aperture zone plate objectives, demonstrating that 54 nm half-period structures can be resolved. The combination of near-wavelength spatial resolution and high temporal resolution opens myriad opportunities in imaging, such as the ability to directly investigate dynamics of nanoscale structures.

  1. Single-shot hyperspectral coherent Raman planar imaging in the range 0-4200 cm-1

    NASA Astrophysics Data System (ADS)

    Bohlin, Alexis; Kliewer, Christopher J.

    2014-10-01

    We propose a technique for ultrabroadband planar coherent Raman spectroscopy that enables wideband chemically selective mapping of molecular partition functions in the gas-phase within a single-laser-shot. A spectral region spanning 0-4200 cm-1 is excited simultaneously, in principle allowing for coherent planar imaging of most all fundamental Raman-active modes. This unique instantaneous and spatially correlated assessment enables multiplexed studies of transient dynamical systems in a two-dimensional (2D) field. Here, we demonstrate single-laser-shot high temperature diagnostics of H2, with spatially resolved 2D measurement of transitions of both the pure-rotational H2 S-branch and the vibrational H2 Q-branch, analyzing the temperature contour of a reacting fuel-species as it evolves at a flame-front.

  2. Optical detection and measurement of living cell morphometric features with single-shot quantitative phase microscopy

    NASA Astrophysics Data System (ADS)

    Bon, Pierre; Savatier, Julien; Merlin, Marine; Wattellier, Benoît; Monneret, Serge

    2012-07-01

    We present a quadriwave lateral shearing interferometer used as a wavefront sensor and mounted on a commercial non-modified transmission white-light microscope as a quantitative phase imaging technique. The setup is designed to simultaneously make measurements with both quantitative transmission phase and fluorescence modes: phase enables enhanced contrasted visualization of the cell structure including intracellular organelles, while fluorescence allows a complete and precise identification of each component. After the characterization of the phase measurement reliability and sensitivity on calibrated samples, we use these two imaging modes to measure the characteristic optical path difference between subcellular elements (mitochondria, actin fibers, and vesicles) and cell medium, and demonstrate that phase-only information should be sufficient to identify some organelles without any labeling, like lysosomes. Proof of principle results show that the technique could be used either as a qualitative tool for the control of cells before an experiment, or for quantitative studies on morphology, behavior, and dynamics of cells or cellular components.

  3. A multi-frame soft x-ray pinhole imaging diagnostic for single-shot applications

    SciTech Connect

    Wurden, G. A.; Coffey, S. K.

    2012-10-15

    For high energy density magnetized target fusion experiments at the Air Force Research Laboratory FRCHX machine, obtaining multi-frame soft x-ray images of the field reversed configuration (FRC) plasma as it is being compressed will provide useful dynamics and symmetry information. However, vacuum hardware will be destroyed during the implosion. We have designed a simple in-vacuum pinhole nosecone attachment, fitting onto a Conflat window, coated with 3.2 mg/cm{sup 2} of P-47 phosphor, and covered with a thin 50-nm aluminum reflective overcoat, lens-coupled to a multi-frame Hadland Ultra intensified digital camera. We compare visible and soft x-ray axial images of translating ({approx}200 eV) plasmas in the FRX-L and FRCHX machines in Los Alamos and Albuquerque.

  4. Single shot Hugoniot of cyclohexane using a spatially resolved laser driven shock wave

    NASA Astrophysics Data System (ADS)

    Bolme, C. A.; McGrane, S. D.; Moore, D. S.; Whitley, V. H.; Funk, D. J.

    2008-11-01

    To develop a more efficient method of determining pressure dependent material response to shock loading, we used the spatial energy distribution of a shock generating laser beam to create a range of nearly one-dimensional stresses in a single laser shot. Ultrafast dynamic ellipsometry was used to measure the Hugoniot and shocked refractive index of cyclohexane subject to this shock loading.

  5. High-fidelity single-shot three-qubit gates via machine learning

    NASA Astrophysics Data System (ADS)

    Zahedinejad, Ehsan; Ghosh, Joydip; Sanders, Barry C.

    Three-qubit quantum gates play a crucial role in quantum error correction and quantum information processing. Here I discuss how to generate policies for quantum control to design three-qubit gates namely, Toffoli, Controlled-Not-Not and Fredkin gates for an architecture of nearest-neighbor-coupled superconducting artificial atoms. The resulted fidelity for each gate is above the 99.9% which is the threshold fidelity for fault-tolerant quantum computing. We test our policy in the presence of decoherence-induced noise as well as show its robustness under random external noise. The three-qubit gates are designed via our machine learning algorithm called Subspace-Selective Self-Adaptive Differential Evolution (SuSSADE). NSERC, AITF and University of Calgarys Eyes High Fellowship Program.

  6. Single shot three‐dimensional pulse sequence for hyperpolarized 13C MRI

    PubMed Central

    Wang, Jiazheng; Wright, Alan J.; Hu, De‐en; Hesketh, Richard

    2016-01-01

    Purpose Metabolic imaging with hyperpolarized 13C‐labeled cell substrates is a promising technique for imaging tissue metabolism in vivo. However, the transient nature of the hyperpolarization, and its depletion following excitation, limits the imaging time and the number of excitation pulses that can be used. We describe here a single‐shot three‐dimensional (3D) imaging sequence and demonstrate its capability to generate 13C MR images in tumor‐bearing mice injected with hyperpolarized [1‐13C]pyruvate. Methods The pulse sequence acquires a stack‐of‐spirals at two spin echoes after a single excitation pulse and encodes the kz‐dimension in an interleaved manner to enhance robustness to B0 inhomogeneity. Spectral‐spatial pulses are used to acquire dynamic 3D images from selected hyperpolarized 13C‐labeled metabolites. Results A nominal spatial/temporal resolution of 1.25 × 1.25 × 2.5 mm3 × 2 s was achieved in tumor images of hyperpolarized [1‐13C]pyruvate and [1‐13C]lactate acquired in vivo. Higher resolution in the z‐direction, with a different k‐space trajectory, was demonstrated in measurements on a thermally polarized [1‐13C]lactate phantom. Conclusion The pulse sequence is capable of imaging hyperpolarized 13C‐labeled substrates at relatively high spatial and temporal resolutions and is robust to moderate system imperfections. Magn Reson Med 77:740–752, 2017. © 2016 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. PMID:26916384

  7. Full-parallax 3D display from single-shot Kinect capture

    NASA Astrophysics Data System (ADS)

    Hong, Seokmin; Dorado, Adrián.; Saavedra, Genaro; Martínez-Corral, Manuel; Shin, Donghak; Lee, Byung-Gook

    2015-05-01

    We propose the fusion between two concepts that are very successful in the area of 3D imaging and sensing. Kinect technology permits the registration, in real time, but with low resolution, of accurate depth maps of big, opaque, diffusing 3D scenes. Our proposal consists on transforming the sampled depth map, provided by the Kinect technology, into an array of microimages whose position; pitch and resolution are in good accordance with the characteristics of an integral- imaging monitor. By projecting this information onto such monitor we are able to produce 3D images with continuous perspective and full parallax.

  8. EXPERIMENTAL TARGET INJECTION AND TRACKING SYSTEM CONSTRUCTION AND SINGLE SHOT TESTING

    SciTech Connect

    PETZOLDT,R.W; ALEXANDER,N.B; DRAKE,T.J; GOODIN,D.T; JONESTRACK,K; VERMILLION,B.A

    2003-09-01

    Targets must be injected into an IFE power plant at a rate of approximately 5 to 10 Hz. Targets must be tracked very accurately to allow driver beams to be aligned with defined points on the targets with accuracy {+-} 150 {micro}m for indirect drive and {+-} 20 {micro}m for direct drive. An experimental target injection and tracking system has been constructed at General Atomics. The injector system will be used as a tool for testing the survivability of various target designs and provide feedback to the target designers. Helium gas propels the targets down an 8 m gun barrel up to 400 m/s. Direct-drive targets are protected in the barrel by sabots that are spring loaded to separate into two halves after acceleration. A sabot deflector directs the sabot halves away from the target injection path. Targets will be optically tracked with laser beams and line-scan cameras. Target position and arrival time will be predicted in real time based on early target position measurements. The system installation will be described. System testing to overcome excessive projectile wear and debris in the gun barrel is presented.

  9. Symmetrical Josephson vortex interferometer as an advanced ballistic single-shot detector

    SciTech Connect

    Soloviev, I. I.; Klenov, N. V.; Bakurskiy, S. V.; Pankratov, A. L.; Kuzmin, L. S.

    2014-11-17

    We consider a ballistic detector formed in an interferometer manner which operational principle relies on Josephson vortex scattering at a measurement potential. We propose an approach to symmetrize the detector scheme and explore arising advantages in the signal-to-noise ratio and in the back-action on a measured object by means of recently presented numerical and analytical methods for modeling of a soliton scattering dynamics in the presence of thermal fluctuations. The obtained characteristics for experimentally relevant parameters reveal practical applicability of the considered schemes including possibility of coupling with standard digital rapid single flux quantum circuits.

  10. Single-shot beam-position monitor for x-ray free electron laser.

    PubMed

    Tono, Kensuke; Kudo, Togo; Yabashi, Makina; Tachibana, Takeshi; Feng, Yiping; Fritz, David; Hastings, Jerome; Ishikawa, Tetsuya

    2011-02-01

    We have developed an x-ray beam-position monitor for detecting the radiation properties of an x-ray free electron laser (FEL). It is composed of four PIN photodiodes that detect backscattered x-rays from a semitransparent diamond film placed in the beam path. The signal intensities from the photodiodes are used to compute the beam intensity and position. A proof-of-principle experiment at a synchrotron light source revealed that the error in the beam position is reduced to below 7 μm by using a nanocrystal diamond film prepared by plasma-enhanced chemical vapor deposition. Owing to high dose tolerance and transparency of the diamond film, the monitor is suitable for routine diagnostics of extremely intense x-ray pulses from the FEL.

  11. Single-shot calibration of soft x-ray mirrors using a sinusoidal transmission grating.

    PubMed

    Shpilman, Z; Ehrlich, Y; Maman, S; Levy, I; Shussman, T; Oren, G; Zakosky Nueberger, I; Hurvitz, G

    2014-11-01

    Calibration of soft x-ray diagnostics is a challenge due to the lack of laboratory-size calibrated sources. An in situ calibration method for newly developed x-ray mirrors, is presented. The x-ray source is produced by laser-matter interaction, and twin transmission gratings which create two identical dispersion lines. The gratings have a sinusoidal transmission function, which produces a highly precise high-orders free spectrum. An x-ray mirror interacts with one of the dispersion lines, and the mirror efficiency curve as a function of wavelength is extracted. Mirror efficiency shows good agreement with the literature, and evidence of water layer may justify the need of in situ calibration.

  12. Single Shot Polarization Characterization of XUV FEL Pulses from Crossed Polarized Undulators

    PubMed Central

    Ferrari, E.; Allaria, E.; Buck, J.; De Ninno, G.; Diviacco, B.; Gauthier, D.; Giannessi, L.; Glaser, L.; Huang, Z.; Ilchen, M.; Lambert, G.; Lutman, A. A.; Mahieu, B.; Penco, G.; Spezzani, C.; Viefhaus, J.

    2015-01-01

    Polarization control is a key feature of light generated by short-wavelength free-electron lasers. In this work, we report the first experimental characterization of the polarization properties of an extreme ultraviolet high gain free-electron laser operated with crossed polarized undulators. We investigate the average degree of polarization and the shot-to-shot stability and we analyze aspects such as existing possibilities for controlling and switching the polarization state of the emitted light. The results are in agreement with predictions based on Gaussian beams propagation. PMID:26314764

  13. Single-shot observation of optical rogue waves in integrable turbulence using time microscopy

    NASA Astrophysics Data System (ADS)

    Suret, Pierre; Koussaifi, Rebecca El; Tikan, Alexey; Evain, Clément; Randoux, Stéphane; Szwaj, Christophe; Bielawski, Serge

    2016-10-01

    Optical fibres are favourable tabletop laboratories to investigate both coherent and incoherent nonlinear waves. In particular, exact solutions of the one-dimensional nonlinear Schrödinger equation such as fundamental solitons or solitons on finite background can be generated by launching periodic, specifically designed coherent waves in optical fibres. It is an open fundamental question to know whether these coherent structures can emerge from the nonlinear propagation of random waves. However the typical sub-picosecond timescale prevented--up to now--time-resolved observations of the awaited dynamics. Here, we report temporal `snapshots' of random light using a specially designed `time-microscope'. Ultrafast structures having peak powers much larger than the average optical power are generated from the propagation of partially coherent waves in optical fibre and are recorded with 250 femtoseconds resolution. Our experiment demonstrates the central role played by `breather-like' structures such as the Peregrine soliton in the emergence of heavy-tailed statistics in integrable turbulence.

  14. Single-shot betatron source size measurement from a laser-wakefield accelerator

    NASA Astrophysics Data System (ADS)

    Köhler, A.; Couperus, J. P.; Zarini, O.; Jochmann, A.; Irman, A.; Schramm, U.

    2016-09-01

    Betatron radiation emitted by accelerated electrons in laser-wakefield accelerators can be used as a diagnostic tool to investigate electron dynamics during the acceleration process. We analyze the spectral characteristics of the emitted Betatron pattern utilizing a 2D x-ray imaging spectroscopy technique. Together with simultaneously recorded electron spectra and x-ray images, the betatron source size, thus the electron beam radius, can be deduced at every shot.

  15. Measuring the intensity and phase of two ultrashort pulses on a single shot

    SciTech Connect

    DeLong, K.W.; Trebino, R.

    1994-12-31

    The method of Frequency-Resolved Optical Gating (FROG) allows one to measure the amplitude and phase of an arbitrary femtosecond pulse on a single laser shot. An extension of this method, which they call Twin Recovery of Excitation E-fields using FROG (TREEFROG) allows one to measure two separate laser pulses. The two dissimilar pulses are used to generate a single ``TREEFROG trace`` from a simple experimental apparatus, and the two pulse electric fields are determined using a modified FROG pulse-retrieval algorithm.

  16. Symptomatic hepatic cyst in a child: treatment with single-shot injection of tetracycline hydrochloride.

    PubMed

    Fabrizzi, Giancarlo; Lanza, Cecilia; Bolli, Valeria; Pieroni, Giovanni

    2009-10-01

    The prevalence of hepatic cysts is 0.1% to 0.5% based on autopsy studies, and 2.5% based on US examinations. Percutaneous therapies are a new alternative to surgery. They include simple percutaneous aspiration, catheter drainage alone, and catheter drainage with sclerotherapy. We present an 11-year-old boy admitted to hospital because of abdominal pain. A diagnosis of simple hepatic cyst was made, which was treated with aspiration and tetracycline hydrochloride solution (5%) injection into the cystic cavity. Complete regression was seen on US and MRI examination at 3 months, with total collapse and deflation of the cyst. The cyst regressed totally, leaving a hyperechoic linear scar on US examination at 1 year. On the basis of the clinical and imaging results obtained, percutaneous sclerotherapy of hepatic cysts can be recommended as the treatment of choice and as a valid alternative to laparoscopy in children.

  17. Single-shot depth camera lens design optimization based on a blur metric

    NASA Astrophysics Data System (ADS)

    Chen, Yung-Lin; Chang, Chuan-Chung; Angot, Ludovic; Chang, Chir-Weei; Tien, Chung-Hao

    2010-08-01

    Computational imaging technology can capture extra information at the sensor and can be used for various photographic applications, including imaging with extended depth of field or depth extraction for 3D applications. The depth estimation from a single captured photograph can be achieved through a phase coded lens and image processing. In this paper, we propose a new method to design a phase coded lens, using a blur metric (BM) as the design criterion. Matlab and Zemax are used for the co-optimization of optical coding and digital image process. The purpose of the design is to find a curve for which the BM changes continuously and seriously within a distance range. We verified our approach by simulation, and got a axial symmetric phase mask as the coded lens. By using a pseudo-random pattern which contains uniform black and white patches as the input image, and the on-axis point spread function (PSF) calculated from Zemax, we can evaluate the BM of the simulated image which is convoluted by the pseudo-random pattern and PSF. In order to ensure the BM curve evaluated from the on-axis PSF represents the result of the whole field of view, the PSF is also optimized to get high off-axis similarity.

  18. Comparative validation of single-shot optical techniques for laparoscopic 3-D surface reconstruction.

    PubMed

    Maier-Hein, L; Groch, A; Bartoli, A; Bodenstedt, S; Boissonnat, G; Chang, P-L; Clancy, N T; Elson, D S; Haase, S; Heim, E; Hornegger, J; Jannin, P; Kenngott, H; Kilgus, T; Müller-Stich, B; Oladokun, D; Röhl, S; Dos Santos, T R; Schlemmer, H-P; Seitel, A; Speidel, S; Wagner, M; Stoyanov, D

    2014-10-01

    Intra-operative imaging techniques for obtaining the shape and morphology of soft-tissue surfaces in vivo are a key enabling technology for advanced surgical systems. Different optical techniques for 3-D surface reconstruction in laparoscopy have been proposed, however, so far no quantitative and comparative validation has been performed. Furthermore, robustness of the methods to clinically important factors like smoke or bleeding has not yet been assessed. To address these issues, we have formed a joint international initiative with the aim of validating different state-of-the-art passive and active reconstruction methods in a comparative manner. In this comprehensive in vitro study, we investigated reconstruction accuracy using different organs with various shape and texture and also tested reconstruction robustness with respect to a number of factors like the pose of the endoscope as well as the amount of blood or smoke present in the scene. The study suggests complementary advantages of the different techniques with respect to accuracy, robustness, point density, hardware complexity and computation time. While reconstruction accuracy under ideal conditions was generally high, robustness is a remaining issue to be addressed. Future work should include sensor fusion and in vivo validation studies in a specific clinical context. To trigger further research in surface reconstruction, stereoscopic data of the study will be made publically available at www.open-CAS.com upon publication of the paper.

  19. Single shot polarization characterization of XUV FEL pulses from crossed polarized undulators

    DOE PAGES

    Ferrari, E.; Allaria, E.; Buck, J.; ...

    2015-08-28

    Polarization control is a key feature of light generated by short-wavelength free-electron lasers. In this work, we report the first experimental characterization of the polarization properties of an extreme ultraviolet high gain free-electron laser operated with crossed polarized undulators. We research the average degree of polarization and the shot-to-shot stability and we analyze aspects such as existing possibilities for controlling and switching the polarization state of the emitted light. The results are in agreement with predictions based on Gaussian beams propagation.

  20. Single-shot tomographic movies of evolving light-velocity objects

    PubMed Central

    Li, Zhengyan; Zgadzaj, Rafal; Wang, Xiaoming; Chang, Yen-Yu; Downer, Michael C.

    2014-01-01

    Tomography—cross-sectional imaging based on measuring radiation transmitted through an object along different directions—enables non-invasive imaging of hidden stationary objects, such as internal bodily organs, from their sequentially measured projections. Here we adapt tomographic methods to visualize—in one laser shot—the instantaneous structure and evolution of a laser-induced object propagating through a transparent Kerr medium. We reconstruct ‘movies’ of a laser pulse’s diffraction, self-focusing and filamentation from phase ‘streaks’ imprinted onto probe pulses that cross the main pulse’s path simultaneously at different angles. Multiple probes are generated and detected compactly and simply, making the system robust, easy to align and adaptable to many problems. Our technique could potentially visualize, for example, plasma wakefield accelerators, optical rogue waves or fast ignitor pulses, light-velocity objects, whose detailed space–time dynamics are known only through intensive computer simulations. PMID:24448430

  1. 33. Perimeter acquisition radar building room #320, perimeter acquisition radar ...

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

    33. Perimeter acquisition radar building room #320, perimeter acquisition radar operations center (PAROC), contains the tactical command and control group equipment required to control the par site. Showing spacetrack monitor console - Stanley R. Mickelsen Safeguard Complex, Perimeter Acquisition Radar Building, Limited Access Area, between Limited Access Patrol Road & Service Road A, Nekoma, Cavalier County, ND

  2. The Acquisition of Serial Publications

    ERIC Educational Resources Information Center

    Huff, William H.

    1970-01-01

    Results of a questionnaire survey of large research libraries on procedures and special problems in serials acquisitions. Cooperative programs are discussed, including the Latin American Cooperative Acquisitions Program and the National Serials Data Program. (JS)

  3. 48 CFR 7.401 - Acquisition considerations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... ACQUISITION PLANNING ACQUISITION PLANNING Equipment Lease or Purchase 7.401 Acquisition considerations. (a...) Financial and operating advantages of alternative types and makes of equipment. (3) Cumulative...

  4. Managing Radical Change in Acquisition

    DTIC Science & Technology

    1998-01-01

    some process innovation, acquisition continues to plague the Defense System and constrain battlefield mobility, information, and speed. Following the... System & Acquisition Management,Monterey,CA,93943 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES...Mark Nissen is Assistant Professor of Information Systems and Acquisition Management at the Naval Postgraduate School (NPS) in Monterey, CA. He

  5. Locative Terms and Warlpiri Acquisition.

    ERIC Educational Resources Information Center

    Bavin, Edith L.

    1990-01-01

    Focuses on the influence of language specific properties in the acquisition of locative expressions. Some of the claims from literature on the acquisition of locative expressions are discussed and data from the acquisition of Warlpiri are presented and discussed in terms of these claims. (Author/CB)

  6. Automatic carrier acquisition system

    NASA Technical Reports Server (NTRS)

    Bunce, R. C. (Inventor)

    1973-01-01

    An automatic carrier acquisition system for a phase locked loop (PLL) receiver is disclosed. It includes a local oscillator, which sweeps the receiver to tune across the carrier frequency uncertainty range until the carrier crosses the receiver IF reference. Such crossing is detected by an automatic acquisition detector. It receives the IF signal from the receiver as well as the IF reference. It includes a pair of multipliers which multiply the IF signal with the IF reference in phase and in quadrature. The outputs of the multipliers are filtered through bandpass filters and power detected. The output of the power detector has a signal dc component which is optimized with respect to the noise dc level by the selection of the time constants of the filters as a function of the sweep rate of the local oscillator.

  7. Data acquisition instruments: Psychopharmacology

    SciTech Connect

    Hartley, D.S. III

    1998-01-01

    This report contains the results of a Direct Assistance Project performed by Lockheed Martin Energy Systems, Inc., for Dr. K. O. Jobson. The purpose of the project was to perform preliminary analysis of the data acquisition instruments used in the field of psychiatry, with the goal of identifying commonalities of data and strategies for handling and using the data in the most advantageous fashion. Data acquisition instruments from 12 sources were provided by Dr. Jobson. Several commonalities were identified and a potentially useful data strategy is reported here. Analysis of the information collected for utility in performing diagnoses is recommended. In addition, further work is recommended to refine the commonalities into a directly useful computer systems structure.

  8. Materiel Acquisition Handbook. Revision

    DTIC Science & Technology

    1987-03-26

    Development Center director appoints the IPR chairman. The TPR chairman assenibles the IPR agenda pacl.age, staffs it within AMC, dIevelops the AL.C postion...to execute MADP agenda package recommendations. PPBES reviews must ensure recent materiel acquisition decisions are reflected and * supported. CHANGES... agenda packages must contain a notice that the package includes proposed changes to the requirements document, with supporting rationale as appropriate

  9. Getting Defense Acquisition Right

    DTIC Science & Technology

    2017-01-01

    Buying Power 1.0 Figure 2. Better Buying Power 2.0 Figure 3. Better Buying Power 3.0 179 Figure 4. Contract Cost Growth on Highest Risk (Major...Crossing Critical Congressional Cost- Growth Thresholds iv Getting Defense Acquisition Right 67 96 97 184 Table 1. Root...Causes for Major Programs Crossing Critical Con­ gressional Cost- Growth Thresholds or Other Major Problems 185 Figure 8. Planned Length of Active

  10. Advanced Data Acquisition Systems

    NASA Technical Reports Server (NTRS)

    Perotti, J.

    2003-01-01

    Current and future requirements of the aerospace sensors and transducers field make it necessary for the design and development of new data acquisition devices and instrumentation systems. New designs are sought to incorporate self-health, self-calibrating, self-repair capabilities, allowing greater measurement reliability and extended calibration cycles. With the addition of power management schemes, state-of-the-art data acquisition systems allow data to be processed and presented to the users with increased efficiency and accuracy. The design architecture presented in this paper displays an innovative approach to data acquisition systems. The design incorporates: electronic health self-check, device/system self-calibration, electronics and function self-repair, failure detection and prediction, and power management (reduced power consumption). These requirements are driven by the aerospace industry need to reduce operations and maintenance costs, to accelerate processing time and to provide reliable hardware with minimum costs. The project's design architecture incorporates some commercially available components identified during the market research investigation like: Field Programmable Gate Arrays (FPGA) Programmable Analog Integrated Circuits (PAC IC) and Field Programmable Analog Arrays (FPAA); Digital Signal Processing (DSP) electronic/system control and investigation of specific characteristics found in technologies like: Electronic Component Mean Time Between Failure (MTBF); and Radiation Hardened Component Availability. There are three main sections discussed in the design architecture presented in this document. They are the following: (a) Analog Signal Module Section, (b) Digital Signal/Control Module Section and (c) Power Management Module Section. These sections are discussed in detail in the following pages. This approach to data acquisition systems has resulted in the assignment of patent rights to Kennedy Space Center under U.S. patent # 6

  11. Data Acquisition Systems

    NASA Technical Reports Server (NTRS)

    1989-01-01

    Technology developed during a joint research program with Langley and Kinetic Systems Corporation led to Kinetic Systems' production of a high speed Computer Automated Measurement and Control (CAMAC) data acquisition system. The study, which involved the use of CAMAC equipment applied to flight simulation, significantly improved the company's technical capability and produced new applications. With Digital Equipment Corporation, Kinetic Systems is marketing the system to government and private companies for flight simulation, fusion research, turbine testing, steelmaking, etc.

  12. Defense ADP Acquisition Study.

    DTIC Science & Technology

    1981-11-30

    management issues. It also provides broad insight into the nature and causes of problems in the ADP acquisition process and offers several strategies ... strategy planning fails to provide the appropriate mission perspective. Curfent top-down strategic planning does not pro- vide the necessary guidance for the...recommendations presented here are more appropriately labeled strategies for change, rather than specific actions for improvement. (1) There Must Be a

  13. Second language acquisition.

    PubMed

    Juffs, Alan

    2011-05-01

    Second language acquisition (SLA) is a field that investigates child and adult SLA from a variety of theoretical perspectives. This article provides a survey of some key areas of concern including formal generative theory and emergentist theory in the areas of morpho-syntax and phonology. The review details the theoretical stance of the two different approaches to the nature of language: generative linguistics and general cognitive approaches. Some results of key acquisition studies from the two theoretical frameworks are discussed. From a generative perspective, constraints on wh-movement, feature geometry and syllable structure, and morphological development are highlighted. From a general cognitive point of view, the emergence of tense and aspect marking from a prototype account of inherent lexical aspect is reviewed. Reference is made to general cognitive learning theories and to sociocultural theory. The article also reviews individual differences research, specifically debate on the critical period in adult language acquisition, motivation, and memory. Finally, the article discusses the relationship between SLA research and second language pedagogy. Suggestions for further reading from recent handbooks on SLA are provided. WIREs Cogni Sci 2011 2 277-286 DOI: 10.1002/wcs.106 For further resources related to this article, please visit the WIREs website.

  14. Data acquisition with Masscomp

    SciTech Connect

    Collins, A.J.

    1988-12-31

    Applications and products for data acquisition and control are abundant. Systems and boards for Apple or IBM products collect, store, and manipulate data up to rates in the 10`s of thousands. These systems may suit your application; if so, it would be good for you to obtain one of these systems. However, if you need speed in the hundreds of thousands of samples per second and you want to store, process, and display data in real time, data acquisition becomes much more complex. Operating system code has to be sufficient to handle the load. A company known as Massachusetts Computer Corporation has modified UNIX operating system code to allow real time data acquisition and control. They call this operating system Real Time Unix, or RTU. They have built a family of computer systems around this operating system with specialized hardware to handle multiple processes and quick communications, which a real time operating system needs to function. This paper covers the basics of an application using a Masscomp 5520 computer. The application is for the KYLE Project Cold Tests in SRL. KYLE is a classified weapons program. The data flow from source to Masscomp, the generic features of Masscomp systems, and the specifics of the Masscomp computer related to this application will be presented.

  15. Complexity in language acquisition.

    PubMed

    Clark, Alexander; Lappin, Shalom

    2013-01-01

    Learning theory has frequently been applied to language acquisition, but discussion has largely focused on information theoretic problems-in particular on the absence of direct negative evidence. Such arguments typically neglect the probabilistic nature of cognition and learning in general. We argue first that these arguments, and analyses based on them, suffer from a major flaw: they systematically conflate the hypothesis class and the learnable concept class. As a result, they do not allow one to draw significant conclusions about the learner. Second, we claim that the real problem for language learning is the computational complexity of constructing a hypothesis from input data. Studying this problem allows for a more direct approach to the object of study--the language acquisition device-rather than the learnable class of languages, which is epiphenomenal and possibly hard to characterize. The learnability results informed by complexity studies are much more insightful. They strongly suggest that target grammars need to be objective, in the sense that the primitive elements of these grammars are based on objectively definable properties of the language itself. These considerations support the view that language acquisition proceeds primarily through data-driven learning of some form.

  16. Assessment of language acquisition.

    PubMed

    de Villiers, Peter A; de Villiers, Jill G

    2010-03-01

    This review addresses questions of what should be assessed in language acquisition, and how to do it. The design of a language assessment is crucially connected to its purpose, whether for diagnosis, development of an intervention plan, or for research. Precise profiles of language strengths and weaknesses are required for clear definitions of the phenotypes of particular language and neurodevelopmental disorders. The benefits and costs of formal tests versus language sampling assessments are reviewed. Content validity, theoretically and empirically grounded in child language acquisition, is claimed to be centrally important for appropriate assessment. Without this grounding, links between phenomena can be missed, and interpretations of underlying difficulties can be compromised. Sensitivity and specificity of assessment instruments are often assessed using a gold standard of existing tests and diagnostic practices, but problems arise if that standard is biased against particular groups or dialects. The paper addresses the issues raised by the goal of unbiased assessment of children from diverse linguistic and cultural backgrounds, especially speakers of non-mainstream dialects or bilingual children. A variety of new approaches are discussed for language assessment, including dynamic assessment, experimental tools such as intermodal preferential looking, and training studies that assess generalization. Stress is placed on the need for measures of the process of acquisition rather than just levels of achievement. Copyright © 2010 John Wiley & Sons, Ltd. For further resources related to this article, please visit the WIREs website.

  17. Design of oil-free simple turbo type 65 K/6 KW helium and neon mixture gas refrigerator for high temperature superconducting power cable cooling

    NASA Astrophysics Data System (ADS)

    Saji, N.; Asakura, H.; Yoshinaga, S.; Ishizawa, T.; Miyake, A.; Obata, M.; Nagaya, S.

    2002-05-01

    For the requirement of HTS facility cooling, we propose oil-free simple turbo-type refrigerator. The working gas is a helium and neon mixture. Two single-stage turbo compressors and two expansion turbines are applied to the cycle. The rotor consists of the compressor impeller, turbine impeller and driving motor, and is supported by foil type gas bearing. The refrigerator requires two rotating machines with excellent reliability and compactness, and the motor power required is 72.5 kW for a refrigeration load of 6 kW. For the cooling of power cable, sub-cooled pressurized liquid nitrogen and a circulation pump must be provided. If the estimated distance between inter-cooling stations is quite long, for example 5 km, plural refrigerators may be set up on one cooling station.

  18. Development of cooling system for 66/6.9kV-20MVA REBCO superconducting transformers with Ne turbo-Brayton refrigerator and subcooled liquid nitrogen

    NASA Astrophysics Data System (ADS)

    Iwakuma, M.; Adachi, K.; Yun, K.; Yoshida, K.; Sato, S.; Suzuki, Y.; Umeno, T.; Konno, M.; Hayashi, H.; Eguchi, T.; Izumi, T.; Shiohara, Y.

    2015-12-01

    We developed a turbo-Brayton refrigerator with Ne gas as a working fluid for a 3 ϕ- 66/6.9kV-2MVA superconducting transformer with coated conductors which was bath-cooled with subcooled LN2. The two-stage compressor and expansion turbine had non-contact magnetic bearings for a long maintenance interval. In the future, we intend to directly install a heat exchanger into the Glass-Fiber-Reinforced-Plastics cryostat of a transformer and make a heat exchange between the working fluid gas and subcooled LN2. In this paper we investigate the behaviour of subcooled LN2 in a test cryostat, in which heater coils were arranged side by side with a flat plate finned-tube heat exchanger. Here a He turbo-Brayton refrigerator was used as a substitute for a Ne turbo-Brayton one. The pressure at the surface of LN2 in the cryostat was one atmosphere. Just under the LN2 surface, a stationary layer of LN2 was created over the depth of 20 cm and temperature dropped from 77 K to 65 K with depth while, in the lower level than that, a natural convection flow of LN2 was formed and temperature was almost uniform over 1 m depth. The boundary plane between the stationary layer and the natural convection region was visible.

  19. Numerical analysis of the static performance of an annular aerostatic gas thrust bearing applied in the cryogenic turbo-expander of the EAST subsystem

    NASA Astrophysics Data System (ADS)

    Tianwei, LAI; Bao, FU; Shuangtao, CHEN; Qiyong, ZHANG; Yu, HOU

    2017-02-01

    The EAST superconducting tokamak, an advanced steady-state plasma physics experimental device, has been built at the Institute of Plasma Physics, Chinese Academy of Sciences. All the toroidal field magnets and poloidal field magnets, made of NbTi/Cu cable-in-conduit conductor, are cooled with forced flow supercritical helium at 3.8 K. The cryogenic system of EAST consists of a 2 kW/4 K helium refrigerator and a helium distribution system for the cooling of coils, structures, thermal shields, bus-lines, etc. The high-speed turbo-expander is an important refrigerating component of the EAST cryogenic system. In the turbo-expander, the axial supporting technology is critical for the smooth operation of the rotor bearing system. In this paper, hydrostatic thrust bearings are designed based on the axial load of the turbo-expander. Thereafter, a computational fluid dynamics-based numerical model of the aerostatic thrust bearing is set up to evaluate the bearing performance. Tilting effect on the pressure distribution and bearing load is analyzed for the thrust bearing. Bearing load and stiffness are compared with different static supply pressures. The net force from the thrust bearings can be calculated for different combinations of bearing clearance and supply pressure.

  20. 48 CFR 18.113 - Interagency acquisitions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Interagency acquisitions. 18.113 Section 18.113 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACTING METHODS AND CONTRACT TYPES EMERGENCY ACQUISITIONS Available Acquisition Flexibilities...

  1. 48 CFR 18.113 - Interagency acquisitions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 1 2014-10-01 2014-10-01 false Interagency acquisitions. 18.113 Section 18.113 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACTING METHODS AND CONTRACT TYPES EMERGENCY ACQUISITIONS Available Acquisition Flexibilities...

  2. 48 CFR 18.113 - Interagency acquisitions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 1 2013-10-01 2013-10-01 false Interagency acquisitions. 18.113 Section 18.113 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACTING METHODS AND CONTRACT TYPES EMERGENCY ACQUISITIONS Available Acquisition Flexibilities...

  3. 48 CFR 18.113 - Interagency acquisitions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 1 2012-10-01 2012-10-01 false Interagency acquisitions. 18.113 Section 18.113 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACTING METHODS AND CONTRACT TYPES EMERGENCY ACQUISITIONS Available Acquisition Flexibilities...

  4. Data acquisition system

    DOEpatents

    Phillips, David T.

    1979-01-01

    A data acquisition system capable of resolving transient pulses in the subnanosecond range. A pulse in an information carrying medium such as light is transmitted through means which disperse the pulse, such as a fiber optic light guide which time-stretches optical pulses by chromatic dispersion. This time-stretched pulse is used as a sampling pulse and is modulated by the signal to be recorded. The modulated pulse may be further time-stretched prior to being recorded. The recorded modulated pulse is unfolded to derive the transient signal by utilizing the relationship of the time-stretching that occurred in the original pulse.

  5. Acquisition-Management Program

    NASA Technical Reports Server (NTRS)

    Avery, Don E.; Vann, A. Vernon; Jones, Richard H.; Rew, William E.

    1987-01-01

    NASA Acquisition Management Subsystem (AMS) program integrated NASA-wide standard automated-procurement-system program developed in 1985. Designed to provide each NASA installation with procurement data-base concept with on-line terminals for managing, tracking, reporting, and controlling contractual actions and associated procurement data. Subsystem provides control, status, and reporting for various procurement areas. Purpose of standardization is to decrease costs of procurement and operation of automatic data processing; increases procurement productivity; furnishes accurate, on-line management information and improves customer support. Written in the ADABAS NATURAL.

  6. Data Acquisition Systems

    NASA Technical Reports Server (NTRS)

    1994-01-01

    In the mid-1980s, Kinetic Systems and Langley Research Center determined that high speed CAMAC (Computer Automated Measurement and Control) data acquisition systems could significantly improve Langley's ARTS (Advanced Real Time Simulation) system. The ARTS system supports flight simulation R&D, and the CAMAC equipment allowed 32 high performance simulators to be controlled by centrally located host computers. This technology broadened Kinetic Systems' capabilities and led to several commercial applications. One of them is General Atomics' fusion research program. Kinetic Systems equipment allows tokamak data to be acquired four to 15 times more rapidly. Ford Motor company uses the same technology to control and monitor transmission testing facilities.

  7. Late Mitochondrial Acquisition, Really?

    PubMed Central

    Degli Esposti, Mauro

    2016-01-01

    This article provides a timely critique of a recent Nature paper by Pittis and Gabaldón that has suggested a late origin of mitochondria in eukaryote evolution. It shows that the inferred ancestry of many mitochondrial proteins has been incorrectly assigned by Pittis and Gabaldón to bacteria other than the aerobic proteobacteria from which the ancestor of mitochondria originates, thereby questioning the validity of their suggestion that mitochondrial acquisition may be a late event in eukaryote evolution. The analysis and approach presented here may guide future studies to resolve the true ancestry of mitochondria. PMID:27289097

  8. HYPERCP data acquisition system

    SciTech Connect

    Kaplan, D.M.; Luebke, W.R.; Chakravorty, A.

    1997-12-31

    For the HyperCP experiment at Fermilab, we have assembled a data acquisition system that records on up to 45 Exabyte 8505 tape drives in parallel at up to 17 MB/s. During the beam spill, data axe acquired from the front-end digitization systems at {approx} 60 MB/s via five parallel data paths. The front-end systems achieve typical readout deadtime of {approx} 1 {mu}s per event, allowing operation at 75-kHz trigger rate with {approx_lt}30% deadtime. Event building and tapewriting are handled by 15 Motorola MVME167 processors in 5 VME crates.

  9. Data-acquisition systems

    SciTech Connect

    Cyborski, D.R.; Teh, K.M.

    1995-08-01

    Up to now, DAPHNE, the data-acquisition system developed for ATLAS, was used routinely for experiments at ATLAS and the Dynamitron. More recently, the Division implemented 2 MSU/DAPHNE systems. The MSU/DAPHNE system is a hybrid data-acquisition system which combines the front-end of the Michigan State University (MSU) DA system with the traditional DAPHNE back-end. The MSU front-end is based on commercially available modules. This alleviates the problems encountered with the DAPHNE front-end which is based on custom designed electronics. The first MSU system was obtained for the APEX experiment and was used there successfully. A second MSU front-end, purchased as a backup for the APEX experiment, was installed as a fully-independent second MSU/DAPHNE system with the procurement of a DEC 3000 Alpha host computer, and was used successfully for data-taking in an experiment at ATLAS. Additional hardware for a third system was bought and will be installed. With the availability of 2 MSU/DAPHNE systems in addition to the existing APEX setup, it is planned that the existing DAPHNE front-end will be decommissioned.

  10. Unsupervised Language Acquisition

    NASA Astrophysics Data System (ADS)

    de Marcken, Carl

    1996-11-01

    This thesis presents a computational theory of unsupervised language acquisition, precisely defining procedures for learning language from ordinary spoken or written utterances, with no explicit help from a teacher. The theory is based heavily on concepts borrowed from machine learning and statistical estimation. In particular, learning takes place by fitting a stochastic, generative model of language to the evidence. Much of the thesis is devoted to explaining conditions that must hold for this general learning strategy to arrive at linguistically desirable grammars. The thesis introduces a variety of technical innovations, among them a common representation for evidence and grammars, and a learning strategy that separates the ``content'' of linguistic parameters from their representation. Algorithms based on it suffer from few of the search problems that have plagued other computational approaches to language acquisition. The theory has been tested on problems of learning vocabularies and grammars from unsegmented text and continuous speech, and mappings between sound and representations of meaning. It performs extremely well on various objective criteria, acquiring knowledge that causes it to assign almost exactly the same structure to utterances as humans do. This work has application to data compression, language modeling, speech recognition, machine translation, information retrieval, and other tasks that rely on either structural or stochastic descriptions of language.

  11. 78 FR 32214 - Land Acquisitions: Appeals of Land Acquisition Decisions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-29

    ...; Docket ID: BIA-2013-0005] RIN 1076-AF15 Land Acquisitions: Appeals of Land Acquisition Decisions AGENCY... of regulations governing decisions by the Secretary to approve or deny applications to acquire land...'s decision to take the land into trust. The Supreme Court has since held that the Quiet Title...

  12. 78 FR 49990 - Land Acquisitions: Appeals of Land Acquisition Decisions

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-16

    ...; Docket ID: BIA-2013-0005] RIN 1076-AF15 Land Acquisitions: Appeals of Land Acquisition Decisions AGENCY... governing decisions by the Secretary to approve or deny applications to acquire land in trust. The public... articulating the process for issuing decisions to acquire land in trust under 25 CFR part 151. The...

  13. Plasmid acquisition in microgravity

    NASA Technical Reports Server (NTRS)

    Juergensmeyer, Margaret A.; Juergensmeyer, Elizabeth A.; Guikema, James A.

    1995-01-01

    In microgravity, bacteria often show an increased resistance to antibiotics. Bacteria can develop resistance to an antibiotic after transformation, the acquisition of DNA, usually in the form of a plasmid containing a gene for resistance to one or more antibiotics. In order to study the capacity of bacteria to become resistant to antibiotics in microgravity, we have modified the standard protocol for transformation of Escherichia coli for use in the NASA-flight-certified hardware package, The Fluid Processing Apparatus (FPA). Here we report on the ability of E. coli to remain competent for long periods of time at temperatures that are readily available on the Space Shuttle, and present some preliminary flight results.

  14. Silicon tracker data acquisition

    SciTech Connect

    Haynes, W.J.

    1997-12-31

    Large particle physics experiments are making increasing technological demands on the design and implementation of real-time data acquisition systems. The LHC will have bunch crossing intervals of 25 nanoseconds and detectors, such as CMS, will contain over 10 million electronic channels. Readout systems will need to cope with 100 kHz rates of 1 MByte-sized events. Over 70% of this voluminous flow will stem from silicon tracker and MSGC devices. This paper describes the techniques currently being harnessed from ASIC devices through to modular microprocessor-based architectures around standards such as VMEbus and PCI. In particular, the experiences gained at the HERA H1 experiment are highlighted where many of the key technological concepts have already been im implemented.

  15. DSPS in data acquisition

    SciTech Connect

    Kirsch, M.; Haeupke, T.; Oelschlaeger, R.; Struck, B.

    1997-12-31

    Off-the-shelf and customized DSP boards in different bus architectures are perfectly suited to act as building blocks for flexible and high performance data acquisition systems. Due to their architecture they can be used to enhance the performance of existing equipment as add ons, as state-of-the-art readout controllers, event builders, on-the-fly data formatters and higher level trigger processors. Applications covering the above mentioned fields with Motorolas 96002 HARC DSP in the DESY HERMES and H1 experiments, at the focal plane polarimeter at KVI and the NIST high flux neutron backscattering spectrometer will be presented. Future possibilities with VME, PCI and PMC boards based on Analog Devices SHARC DSP will be discussed. Systems on the base of Texas Instruments TMS320C6X promise to provide unprecedented performance.

  16. Deepwater seismic acquisition technology

    SciTech Connect

    Caldwell, J.

    1996-09-01

    Although truly new technology is not required for successful acquisition of seismic data in deep Gulf of Mexico waters, it is helpful to review some basic aspects of these seismic surveys. Additionally, such surveys are likely to see early use of some emerging new technology which can improve data quality. Because such items as depth imaging, borehole seismic, 4-D and marine 3-component recording were mentioned in the May 1996 issue of World Oil, they are not discussed again here. However, these technologies will also play some role in the deepwater seismic activities. What is covered in this paper are some new considerations for: (1) longer data records needed in deeper water, (2) some pros and cons of very long steamer use, and (3) two new commercial systems for quantifying data quality.

  17. Universals of Second Language Acquisition.

    ERIC Educational Resources Information Center

    Eckman, Fred R., Ed.; And Others

    Works on second language acquisition theories, affective variables and communicative competence, and interlanguage were compiled as a result of a symposium on universals of second language acquisition at the University of Wisconsin, Milwaukee. The papers include: "On the Variability of Interlangauge Systems" (Elaine Tarone); "Memory, Learning, and…

  18. Microform Developments Related to Acquisitions.

    ERIC Educational Resources Information Center

    Sullivan, Robert C.

    1985-01-01

    Focuses on significant developments of the recent past in acquisition and control of library microforms. Highlights include reference works essential to acquisition of microforms and microform equipment, microform utilization in libraries, bibliographic control, computer output microfilm (COM) and the Copyright Law, technological developments,…

  19. Markedness and Second Language Acquisition.

    ERIC Educational Resources Information Center

    Gil-Byeon, Ja

    1999-01-01

    Discusses whether markedness is at work in second-language acquisition in the same way it is in first-language acquisition when Korean speakers learn English as a second language and English speakers learn Korean as a second language. Results are discussed in terms of no access to universal grammar, partial access to universal grammar, and access…

  20. Knowledge Acquisition in Observational Astronomy.

    ERIC Educational Resources Information Center

    Vosniadou, Stella

    This paper presents findings from research on knowledge acquisition in observational astronomy to demonstrate the kinds of intuitive models children form and to show how these models influence the acquisition of science knowledge. Sixty children of approximate ages 6, 9, and 12 were given a questionnaire to investigate their knowledge of the size,…

  1. Acquisition Policies. SPEC Kit 12.

    ERIC Educational Resources Information Center

    Association of Research Libraries, Washington, DC. Office of Management Studies.

    This collection of acquisition materials from member libraries of the Association of Research Libraries (ARL) contains: (1) acquisition policies from Brigham Young University, Iowa State University, and the University of Cincinnati; (2) book selection policies from the University of Nebraska Undergraduate Library and Georgetown University; (3) an…

  2. Investment and Second Language Acquisition

    ERIC Educational Resources Information Center

    Pittaway, Daniel S.

    2004-01-01

    The article argues that Norton Peirce's (1995) concept of a language learner's investment should figure centrally in how instructors address the needs of adult learners in ESL classrooms. Investment is discussed in relation to second language acquisition research that addresses the role of social factors in second language acquisition. The article…

  3. STIS CCD Target Acquisition Workout

    NASA Astrophysics Data System (ADS)

    Downes, Ron

    1997-07-01

    Following update of STIS flight acquisitions and acq/peak software, redemonstrate the capability to perform point source and peakup acquisitions of a bright target. Then demonstrate ability of the STIS FSW to locate targets more typical of those in the science program.

  4. 48 CFR 207.401 - Acquisition considerations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Acquisition considerations. 207.401 Section 207.401 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM... Acquisition considerations. If the equipment will be leased for more than 60 days, the requiring activity...

  5. 48 CFR 34.004 - Acquisition strategy.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Acquisition strategy. 34... CATEGORIES OF CONTRACTING MAJOR SYSTEM ACQUISITION General 34.004 Acquisition strategy. The program manager, as specified in agency procedures, shall develop an acquisition strategy tailored to the...

  6. 48 CFR 3034.004 - Acquisition strategy.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 7 2010-10-01 2010-10-01 false Acquisition strategy. 3034.004 Section 3034.004 Federal Acquisition Regulations System DEPARTMENT OF HOMELAND SECURITY, HOMELAND... Acquisition strategy. See (HSAR) 48 CFR 3009.570 for policy applicable to acquisition strategies that...

  7. 48 CFR 873.105 - Acquisition planning.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Acquisition planning. 873.105 Section 873.105 Federal Acquisition Regulations System DEPARTMENT OF VETERANS AFFAIRS DEPARTMENT... planning. (a) Acquisition planning is an indispensable component of the total acquisition process. (b)...

  8. 48 CFR 873.105 - Acquisition planning.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... SUPPLEMENTARY REGULATIONS SIMPLIFIED ACQUISITION PROCEDURES FOR HEALTH-CARE RESOURCES 873.105 Acquisition... the acquisition of health-care resources consisting of commercial services or the use of medical equipment or space, where the acquisition is expected to exceed the simplified acquisition threshold...

  9. 48 CFR 234.004 - Acquisition strategy.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Acquisition strategy. 234..., DEPARTMENT OF DEFENSE SPECIAL CATEGORIES OF CONTRACTING MAJOR SYSTEM ACQUISITION 234.004 Acquisition strategy. (1) See 209.570 for policy applicable to acquisition strategies that consider the use of lead...

  10. Ocean Data Acquisition System

    NASA Technical Reports Server (NTRS)

    Johnson, B.; Cavanaugh, J.; Smith, J.; Esaias, W.

    1988-01-01

    The Ocean Data Acquisition System (ODAS) is a low cost instrument with potential commercial application. It is easily mounted on a small aircraft and flown over the coastal zone ocean to remotely measure sea surface temperature and three channels of ocean color information. From this data, chlorophyll levels can be derived for use by ocean scientists, fisheries, and environmental offices. Data can be transmitted to shipboard for real-time use with sea truth measurements, ocean productivity estimates and fishing fleet direction. The aircraft portion of the system has two primary instruments: an IR radiometer to measure sea surface temperature and a three channel visible spectro-radiometer for 460, 490, and 520 nm wavelength measurements from which chlorophyll concentration can be derived. The aircraft package contains a LORAN-C unit for aircraft location information, clock, on-board data processor and formatter, digital data storage, packet radio terminal controller, and radio transceiver for data transmission to a ship. The shipboard package contains a transceiver, packet terminal controller, data processing and storage capability, and printer. Both raw data and chlorophyll concentrations are available for real-time analysis.

  11. Determination of sodium cromoglycate in human plasma by liquid chromatography-mass spectrometry in the turbo ion spray mode.

    PubMed

    Ozou, M L; Girault, J; Malgouyat, J M; Pasquier, O

    2001-12-25

    A highly sensitivity liquid chromatography-tandem mass spectrometry method has been developed for the quantitation of sodium cromoglycate (SCG) in human plasma. The method was validated over a linear range of 0.100-50.0 ng/ml, using 13C4 sodium cromoglycate as the internal standard. Compounds were extracted from 1.0 ml of lithium heparin plasma by methanol elution of C18 solid-phase extraction cartridges. The dried residue was reconstituted with 100 microl of 0.01 N HCl. and 30 microl was injected onto the LC-MS-MS system. Chromatographic separation was achieved on a C8 (3.5 microm) column with an isocratic mobile phase of methanol-water-0.5 M ammonium acetate (35:64.8:0.2, v/v/v). The analytes were detected with a PE Sciex API 3000 mass spectrometer using turbo ion spray with positive ionization. Ions monitored in the multiple reaction monitoring (MRM) mode were m/z 469.2 (precursor ion) to m/z 245.1 (product ion) for SCG and m/z 473.2 (precursor ion) to m/z 247.1 (product ion) for 13C4 SCG (I.S.). The average recoveries of SCG and the I.S. from human plasma were 91 and 87%, respectively. The low limit of quantitation was 0.100 ng/ml. Results from a 4-day validation study demonstrated excellent precision (C.V.% values were between 1.9 and 6.5%) and accuracy (-5.4 to - 1.2%) across the calibration range of 0.100-50.0 ng/ml.

  12. An Active Broad Area Cooling Model of a Cryogenic Propellant Tank with a Single Stage Reverse Turbo-Brayton Cycle Cryocooler

    NASA Technical Reports Server (NTRS)

    Guzik, Monica C.; Tomsik, Thomas M.

    2011-01-01

    As focus shifts towards long-duration space exploration missions, an increased interest in active thermal control of cryogenic propellants to achieve zero boil-off of cryogens has emerged. An active thermal control concept of considerable merit is the integration of a broad area cooling system for a cryogenic propellant tank with a combined cryocooler and circulator system that can be used to reduce or even eliminate liquid cryogen boil-off. One prospective cryocooler and circulator combination is the reverse turbo-Brayton cycle cryocooler. This system is unique in that it has the ability to both cool and circulate the coolant gas efficiently in the same loop as the broad area cooling lines, allowing for a single cooling gas loop, with the primary heat rejection occurring by way of a radiator and/or aftercooler. Currently few modeling tools exist that can size and characterize an integrated reverse turbo-Brayton cycle cryocooler in combination with a broad area cooling design. This paper addresses efforts to create such a tool to assist in gaining a broader understanding of these systems, and investigate their performance in potential space missions. The model uses conventional engineering and thermodynamic relationships to predict the preliminary design parameters, including input power requirements, pressure drops, flow rate, cycle performance, cooling lift, broad area cooler line sizing, and component operating temperatures and pressures given the cooling load operating temperature, heat rejection temperature, compressor inlet pressure, compressor rotational speed, and cryogenic tank geometry. In addition, the model allows for the preliminary design analysis of the broad area cooling tubing, to determine the effect of tube sizing on the reverse turbo-Brayton cycle system performance. At the time this paper was written, the model was verified to match existing theoretical documentation within a reasonable margin. While further experimental data is needed for full

  13. Processes Asunder: Acquisition & Planning Misfits

    DTIC Science & Technology

    2009-03-26

    St ra te gy Re se ar ch Pr oj ec t PROCESSES ASUNDER: ACQUISITION & PLANNING MISFITS BY CHÉRIE A. SMITH Department of Army Civilian DISTRIBUTION...Asunder: Acquisition & Planning Misfits 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Chérie A. Smith 5d. PROJECT NUMBER 5e...include area code) Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std. Z39.18 USAWC STRATEGY RESEARCH PROJECT PROCESSES ASUNDER: ACQUISITION & PLANNING

  14. Space storable propellant acquisition system

    NASA Technical Reports Server (NTRS)

    Tegart, J. R.; Uney, P. E.; Anderson, J. E.; Fester, D. A.

    1972-01-01

    Surface tension propellant acquisition concepts for an advanced spacecraft propulsion system having a 10-year mission capability were investigated. Surface tension systems were specified because they were shown to be the best propellant acquisition technique for various interplanetery spacecraft in a prior study. A variety of surface tension concepts for accomplishing propellant acquisition were formulated for the baseline space storable propulsion module and Jupiter Orbiter mission. Analyses and evaluations were then conducted on each candidate concept to assess fabricability, performance capability, and spacecraft compatibility. A comparative evaluation of the results showed the Fruhof-class of low-g surface tension systems to be preferred for these interplanetary applications.

  15. Automated ship image acquisition

    NASA Astrophysics Data System (ADS)

    Hammond, T. R.

    2008-04-01

    The experimental Automated Ship Image Acquisition System (ASIA) collects high-resolution ship photographs at a shore-based laboratory, with minimal human intervention. The system uses Automatic Identification System (AIS) data to direct a high-resolution SLR digital camera to ship targets and to identify the ships in the resulting photographs. The photo database is then searchable using the rich data fields from AIS, which include the name, type, call sign and various vessel identification numbers. The high-resolution images from ASIA are intended to provide information that can corroborate AIS reports (e.g., extract identification from the name on the hull) or provide information that has been omitted from the AIS reports (e.g., missing or incorrect hull dimensions, cargo, etc). Once assembled into a searchable image database, the images can be used for a wide variety of marine safety and security applications. This paper documents the author's experience with the practicality of composing photographs based on AIS reports alone, describing a number of ways in which this can go wrong, from errors in the AIS reports, to fixed and mobile obstructions and multiple ships in the shot. The frequency with which various errors occurred in automatically-composed photographs collected in Halifax harbour in winter time were determined by manual examination of the images. 45% of the images examined were considered of a quality sufficient to read identification markings, numbers and text off the entire ship. One of the main technical challenges for ASIA lies in automatically differentiating good and bad photographs, so that few bad ones would be shown to human users. Initial attempts at automatic photo rating showed 75% agreement with manual assessments.

  16. The acquisition of syntactic knowledge

    SciTech Connect

    Berwick, R.

    1985-01-01

    This work in computational linguistics describes a break-through in the design of expert systems because it suggests how extensive knowledge might be acquired automatically, without outside intervention. Computationally, the author looks at the developmental problem of the interaction between innate genetic endowment and environmental input, using computational methods to uncover the constraints on the acquisition of syntactic knowledge. Learning and syntax problems are also explored: how lexical categories, phonological rule systems, and phrase structure rules are learned; the role of semantic-syntactic interaction in language acquisition; how a ''parameter setting'' model may be formalized as a learning procedure; how multiple constraints interact to aid acquisition; how transformational-type rules may be learned; and the role of lexical ambiguity in language acquisition.

  17. Acquisition of Books and Pamphlets

    ERIC Educational Resources Information Center

    Thompson, Lawrence S.

    1970-01-01

    Acquisitions of current printed works in the research library is a complex process because of the proliferation of publishers and publications in all subject areas. Cooperation among the librarian, subject specialist, and dealers is necessary. (JS)

  18. Acquisition Activities in Intensive Reading.

    ERIC Educational Resources Information Center

    Zhenghua, Xu

    1998-01-01

    Discusses four possible ways to conduct language-acquisition activities in the foreign-language classroom: (1) vivid linking; (2) story retelling; (3) self-directed statement; and (4) role playing. (Author/VWL)

  19. Schizophrenia and second language acquisition.

    PubMed

    Bersudsky, Yuly; Fine, Jonathan; Gorjaltsan, Igor; Chen, Osnat; Walters, Joel

    2005-05-01

    Language acquisition involves brain processes that can be affected by lesions or dysfunctions in several brain systems and second language acquisition may depend on different brain substrates than first language acquisition in childhood. A total of 16 Russian immigrants to Israel, 8 diagnosed schizophrenics and 8 healthy immigrants, were compared. The primary data for this study were collected via sociolinguistic interviews. The two groups use language and learn language in very much the same way. Only exophoric reference and blocking revealed meaningful differences between the schizophrenics and healthy counterparts. This does not mean of course that schizophrenia does not induce language abnormalities. Our study focuses on those aspects of language that are typically difficult to acquire in second language acquisition. Despite the cognitive compromises in schizophrenia and the manifest atypicalities in language of speakers with schizophrenia, the process of acquiring a second language seems relatively unaffected by schizophrenia.

  20. STIS Target Acquisitions During SMOV

    NASA Astrophysics Data System (ADS)

    Katsanis, Rocio M.; Downes, Ron; Hartig, George; Kraemer, Steve

    1997-07-01

    We summarize the first results on the analysis of in-flight STIS target acquisition (ACQ and ACQ/PEAK). These results show that the STIS target acquisition (ACQ) is working very accurately for point sources (within 0.5 pixels = 0.025 arcseconds), about 4 times better than specified in the Instrument Handbook. As a result of the accuracy of the ACQ algorithm, we are no longer recommending to perform ACQ/PEAKs for the 0.2 arcsecond wide slits. For diffuse acquisitions the accuracy varies with target size. Although analysis of ACQ/PEAK data is hampered by a flight software problem, we anticipate that peakups will be accurate to roughly ±5% of the slit width (instead of the ±15% pr eviously advertised). We are implementing several enhancements to the flight software that will take effect by mid- August to improve the quality of the acquisitions.

  1. User Manual for Beta Version of TURBO-GRD: A Software System for Interactive Two-Dimensional Boundary/ Field Grid Generation, Modification, and Refinement

    NASA Technical Reports Server (NTRS)

    Choo, Yung K.; Slater, John W.; Henderson, Todd L.; Bidwell, Colin S.; Braun, Donald C.; Chung, Joongkee

    1998-01-01

    TURBO-GRD is a software system for interactive two-dimensional boundary/field grid generation. modification, and refinement. Its features allow users to explicitly control grid quality locally and globally. The grid control can be achieved interactively by using control points that the user picks and moves on the workstation monitor or by direct stretching and refining. The techniques used in the code are the control point form of algebraic grid generation, a damped cubic spline for edge meshing and parametric mapping between physical and computational domains. It also performs elliptic grid smoothing and free-form boundary control for boundary geometry manipulation. Internal block boundaries are constructed and shaped by using Bezier curve. Because TURBO-GRD is a highly interactive code, users can read in an initial solution, display its solution contour in the background of the grid and control net, and exercise grid modification using the solution contour as a guide. This process can be called an interactive solution-adaptive grid generation.

  2. An Analysis of Army Rapid Acquisition

    DTIC Science & Technology

    2015-09-01

    Strategy ........54 6. Value Center Six: Life Cycle Costs ............................................54 7. Value Center Seven: Lessons Learned...information assurance strategy ANPP Apple new product process AOA analysis of alternatives APB acquisition program baseline APC acquisition program...candidate APO Army Project Office APUC average procurement unit cost AS acquisition strategy ASOM acquisition system operating model BBP better

  3. A turbo engine with automatic transmission? How to marry chemicomotion to the subtleties and robustness of life.

    PubMed

    Koefoed, Sarah; Otten, Marijke; Koebmann, Brian; Bruggeman, Frank; Bakker, Barbara; Snoep, Jacky; Krab, Klaas; van Spanning, Rob; van Verseveld, Henk; Jensen, Peter; Koster, Johanna; Westerhoff, Hans

    2002-09-10

    Most genomes are much more complex than required for the minimum chemistry of life. Evolution has selected sophistication more than life itself. Could this also apply to bioenergetics? We first examine mechanisms through which bioenergetics could deliver sophistication. We illustrate possible benefits of the turbo-charging of catabolic pathways, of loose coupling, low-gear catabolism, automatic transmission in energy coupling, and of homeostasis. Mechanisms for such phenomena may reside at the level of individual proton pumps, or consist of rerouting of electrons over parallel pathways. The mechanisms may be confined to preexisting components, or involve the plasticity of gene expression that is so characteristic of most living organisms. These possible benefits lead us to the conjecture that also bioenergetics has evolved more for sophistication than for necessity. We next discuss a hitherto unresolved enigma, i.e. that bioenergetics does not seem to be critical for the physiological state. To decide on how critical bioenergetics is, we quantified the control exerted by catabolism on important physiological functions such as growth rate and growth yield. We also determined whether a growth inhibition mostly affected bioenergetics (catabolism) or anabolism; if ATP increases with growth rate, then growth should be considered energy (catabolism) limited. The experimental results for Escherichia coli pinpoint the enigma: its energy metabolism (catabolism) is not critical for growth rate. These results might suggest that because it has no direct control over cell function, bioenergetics is unimportant. Paradoxically however, in biology, highly important mechanisms tend to have little control on cell function, precisely because of that importance. Sophistication in terms of homeostatic mechanisms has evolved to guarantee robustness of the most important functions: The most important mechanisms are redundant in biology. Bioenergetics may be an excellent example of this

  4. Evaluation of a multiple spin- and gradient-echo (SAGE) EPI acquisition with SENSE acceleration: applications for perfusion imaging in and outside the brain.

    PubMed

    Skinner, Jack T; Robison, Ryan K; Elder, Christopher P; Newton, Allen T; Damon, Bruce M; Quarles, C Chad

    2014-12-01

    Perfusion-based changes in MR signal intensity can occur in response to the introduction of exogenous contrast agents and endogenous tissue properties (e.g. blood oxygenation). MR measurements aimed at capturing these changes often implement single-shot echo planar imaging (ssEPI). In recent years ssEPI readouts have been combined with parallel imaging (PI) to allow fast dynamic multi-slice imaging as well as the incorporation of multiple echoes. A multiple spin- and gradient-echo (SAGE) EPI acquisition has recently been developed to allow measurement of transverse relaxation rate (R2 and R2(*)) changes in dynamic susceptibility contrast (DSC)-MRI experiments in the brain. With SAGE EPI, the use of PI can influence image quality, temporal resolution, and achievable echo times. The effect of PI on dynamic SAGE measurements, however, has not been evaluated. In this work, a SAGE EPI acquisition utilizing SENSE PI and partial Fourier (PF) acceleration was developed and evaluated. Voxel-wise measures of R2 and R2(*) in healthy brain were compared using SAGE EPI and conventional non-EPI multiple echo acquisitions with varying SENSE and PF acceleration. A conservative SENSE factor of 2 with PF factor of 0.73 was found to provide accurate measures of R2 and R2(*) in white (WM) (rR2=[0.55-0.79], rR2*=[0.47-0.71]) and gray (GM) matter (rR2=[0.26-0.59], rR2*=[0.39-0.74]) across subjects. The combined use of SENSE and PF allowed the first dynamic SAGE EPI measurements in muscle, with a SENSE factor of 3 and PF factor of 0.6 providing reliable relaxation rate estimates when compared to multi-echo methods. Application of the optimized SAGE protocol in DSC-MRI of high-grade glioma patients provided T1 leakage-corrected estimates of CBV and CBF as well as mean vessel diameter (mVD) and simultaneous measures of DCE-MRI parameters K(trans) and ve. Likewise, application of SAGE in a muscle reperfusion model allowed dynamic measures of R2', a parameter that has been shown to correlate

  5. 48 CFR 1318.270 - Emergency acquisition flexibilities.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... flexibilities. 1318.270 Section 1318.270 Federal Acquisition Regulations System DEPARTMENT OF COMMERCE CONTRACTING METHODS AND CONTRACT TYPES EMERGENCY ACQUISITIONS Emergency Acquisition Flexibilities 1318.270 Emergency acquisition flexibilities. (a) Authorizing emergency acquisition flexibilities. The process...

  6. 48 CFR 1318.270 - Emergency acquisition flexibilities.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... flexibilities. 1318.270 Section 1318.270 Federal Acquisition Regulations System DEPARTMENT OF COMMERCE CONTRACTING METHODS AND CONTRACT TYPES EMERGENCY ACQUISITIONS Emergency Acquisition Flexibilities 1318.270 Emergency acquisition flexibilities. (a) Authorizing emergency acquisition flexibilities. The process...

  7. 48 CFR 1318.270 - Emergency acquisition flexibilities.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... flexibilities. 1318.270 Section 1318.270 Federal Acquisition Regulations System DEPARTMENT OF COMMERCE CONTRACTING METHODS AND CONTRACT TYPES EMERGENCY ACQUISITIONS Emergency Acquisition Flexibilities 1318.270 Emergency acquisition flexibilities. (a) Authorizing emergency acquisition flexibilities. The process...

  8. 48 CFR 1318.270 - Emergency acquisition flexibilities.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... flexibilities. 1318.270 Section 1318.270 Federal Acquisition Regulations System DEPARTMENT OF COMMERCE CONTRACTING METHODS AND CONTRACT TYPES EMERGENCY ACQUISITIONS Emergency Acquisition Flexibilities 1318.270 Emergency acquisition flexibilities. (a) Authorizing emergency acquisition flexibilities. The process...

  9. 48 CFR 1318.270 - Emergency acquisition flexibilities.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... flexibilities. 1318.270 Section 1318.270 Federal Acquisition Regulations System DEPARTMENT OF COMMERCE CONTRACTING METHODS AND CONTRACT TYPES EMERGENCY ACQUISITIONS Emergency Acquisition Flexibilities 1318.270 Emergency acquisition flexibilities. (a) Authorizing emergency acquisition flexibilities. The process...

  10. 48 CFR Appendix - Federal Acquisition Regulation (FAR) Index

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Federal Acquisition Regulation (FAR) Index Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACT... (IFMS) Contract clause. FAR Index Federal Acquisition Regulation (FAR) Index Editorial Note:...

  11. 48 CFR Appendix - Federal Acquisition Regulation (FAR) Index

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 1 2011-10-01 2011-10-01 false Federal Acquisition Regulation (FAR) Index Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION CONTRACT... (IFMS) Contract clause. FAR Index Federal Acquisition Regulation (FAR) Index Editorial Note:...

  12. Iron acquisition by Cryptococcus neoformans.

    PubMed

    Vartivarian, S E; Cowart, R E; Anaissie, E J; Tashiro, T; Sprigg, H A

    1995-01-01

    Iron is an essential element for the growth and metabolism of microbial cells. Most pathogenic microbes elaborate powerful iron chelating agents (siderophores) to mobilize iron from ferric ligands. The pathogenic yeast, Cryptococcus neoformans has not been found to produce siderophores and its mechanism of iron acquisition is unknown. This investigation explored an alternative pathway for iron acquisition by examining the interactions of iron with the cell surface. Iron uptake experiments were conducted utilizing radiolabelled ferrous iron and ferric iron chelates, with evidence for the presence of iron(II) receptors and the generation of ferrous iron by surface reduction. Hyperbolic kinetics were found when 59FeII was presented to the organism and uptake was blocked with bathophenanthroline sulphonate, an Fe2+ chelator. The yeast also acquired iron as [59Fe3+]-citrate and [59Fe3+]-pyrophosphate while bathophenanthroline sulphonate reduced the acquisition of these ferric ligands by 48% and 52% respectively. Pre-incubation with either ferric ligand also reduced iron acquisition by 50%. KCN inhibited uptake of iron(II) by 90% and uptake of [59Fe3+]-pyrophosphate and [59Fe3+]-citrate by 46% and 56% respectively; dinitrophenol had no effect on these processes. The data suggest that C. neoformans can (i) generate ferrous iron at the cell surface via a reduction of ferric chelates, with the subsequent acquisition of the ferrous iron, and (ii) acquire iron through the interaction of ferric chelates with a surface component.

  13. Space Acquisitions: Challenges Facing DOD as it Changes Approaches to Space Acquisitions

    DTIC Science & Technology

    2016-03-09

    SPACE ACQUISITIONS Challenges Facing DOD as it Changes Approaches to Space Acquisitions Statement of Cristina T. Chaplain...2016 SPACE ACQUISITIONS Challenges Facing DOD as it Changes Approaches to Space Acquisitions Why GAO Did This Study DOD is shifting its traditional...approach to space acquisitions, bolstering its protection of space systems, and engaging with more commercial providers. Given the time and

  14. Computational models of syntactic acquisition.

    PubMed

    Yang, Charles

    2012-03-01

    The computational approach to syntactic acquisition can be fruitfully pursued by integrating results and perspectives from computer science, linguistics, and developmental psychology. In this article, we first review some key results in computational learning theory and their implications for language acquisition. We then turn to examine specific learning models, some of which exploit distributional information in the input while others rely on a constrained space of hypotheses, yet both approaches share a common set of characteristics to overcome the learning problem. We conclude with a discussion of how computational models connects with the empirical study of child grammar, making the case for computationally tractable, psychologically plausible and developmentally realistic models of acquisition. WIREs Cogn Sci 2012, 3:205-213. doi: 10.1002/wcs.1154 For further resources related to this article, please visit the WIREs website.

  15. Acquisition Reform: Three Big Ideas

    DTIC Science & Technology

    2015-05-19

    Standard Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 Three Acq Reform Big Ideas 5 /19/2015 2 (1) Competing Capability Needs Among Services...to sponsor and users • Not required to be an acquisition expert • Tenure not as important Summary: 3 Big Ideas 5 /19/2015 19 (1) Competing...Acquisition Reform Three Big Ideas The provocative views expressed here are not those of the Department of Defense, DAU, or perhaps even the

  16. Stochastic reinforcement benefits skill acquisition.

    PubMed

    Dayan, Eran; Averbeck, Bruno B; Richmond, Barry J; Cohen, Leonardo G

    2014-02-14

    Learning complex skills is driven by reinforcement, which facilitates both online within-session gains and retention of the acquired skills. Yet, in ecologically relevant situations, skills are often acquired when mapping between actions and rewarding outcomes is unknown to the learning agent, resulting in reinforcement schedules of a stochastic nature. Here we trained subjects on a visuomotor learning task, comparing reinforcement schedules with higher, lower, or no stochasticity. Training under higher levels of stochastic reinforcement benefited skill acquisition, enhancing both online gains and long-term retention. These findings indicate that the enhancing effects of reinforcement on skill acquisition depend on reinforcement schedules.

  17. 75 FR 1567 - Defense Federal Acquisition Regulation Supplement; Foreign Participation in Acquisitions in...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-12

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF DEFENSE Defense Acquisition Regulations System 48 CFR Parts 225 and 252 Defense Federal Acquisition Regulation Supplement; Foreign Participation in Acquisitions in Support of Operations in Afghanistan AGENCY:...

  18. 75 FR 19167 - Federal Acquisition Regulation; Federal Acquisition Circular 2005-41; Introduction

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-13

    ... Federal Acquisition Regulations; Federal Acquisition Circular 2005-41; Introduction; FAR Case 2009-005... Acquisition Circular 2005-41; Introduction AGENCIES: Department of Defense (DoD), General...

  19. 76 FR 30362 - Federal Acquisition Regulation; Submission for OMB Review; Acquisition of Helium

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-25

    ...; Submission for OMB Review; Acquisition of Helium AGENCY: Department of Defense (DOD), General Services... approved information collection requirement concerning acquisition of helium. Public comments are... Collection 9000- 0113, Acquisition of Helium, by any of the following methods: Regulations.gov :...

  20. Data Acquisition for Modular Biometric Monitoring System

    NASA Technical Reports Server (NTRS)

    Chmiel, Alan J. (Inventor); Humphreys, Bradley T. (Inventor); Grodsinsky, Carlos M. (Inventor)

    2014-01-01

    A modular system for acquiring biometric data includes a plurality of data acquisition modules configured to sample biometric data from at least one respective input channel at a data acquisition rate. A representation of the sampled biometric data is stored in memory of each of the plurality of data acquisition modules. A central control system is in communication with each of the plurality of data acquisition modules through a bus. The central control system is configured to collect data asynchronously, via the bus, from the memory of the plurality of data acquisition modules according to a relative fullness of the memory of the plurality of data acquisition modules.