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Sample records for high pitch modes

  1. Dual source multidetector CT-angiography before transcatheter aortic valve implantation (TAVI) using a high-pitch spiral acquisition mode

    Energy Technology Data Exchange (ETDEWEB)

    Wuest, W.; Anders, K.; May, M.S.; Uder, M. [University of Erlangen, Department of Radiology, Erlangen (Germany); Schuhbaeck, A.; Gauss, S.; Marwan, M.; Arnold, M.; Muschiol, G.; Daniel, W.G.; Achenbach, S. [University of Erlangen, Department of Cardiology, Erlangen (Germany); Ensminger, S. [University of Erlangen, Department of Cardiac Surgery, Erlangen (Germany)

    2012-01-15

    Transcatheter Aortic Valve Implantation (TAVI) is an alternative to surgical valve replacement in high risk patients. Angiography of the aortic root, aorta and iliac arteries is required to select suitable candidates, but contrast agents can be harmful due to impaired renal function. We evaluated ECG-triggered high-pitch spiral dual source Computed Tomography (CT) with minimized volume of contrast agent to assess aortic root anatomy and vascular access. 42 patients (82 {+-} 6 years) scheduled for TAVI underwent dual source (DS) CT angiography (CTA) of the aorta using a prospectively ECG-triggered high-pitch spiral mode (pitch = 3.4) with 40 mL iodinated contrast agent. We analyzed aortic root/iliac dimensions, attenuation, contrast to noise ratio (CNR), image noise and radiation exposure. Aortic root/iliac dimensions and distance of coronary ostia from the annulus could be determined in all cases. Mean aortic and iliac artery attenuation was 320 {+-} 70 HU and 340 {+-} 77 HU. Aortic/iliac CNR was 21.7 {+-} 6.8 HU and 14.5 {+-} 5.4 HU using 100 kV (18.8 {+-} 4.1 HU and 8.7 {+-} 2.6 HU using 120 kV). Mean effective dose was 4.5 {+-} 1.2 mSv. High-pitch spiral DSCTA can be used to assess the entire aorta and iliac arteries in TAVI candidates with a low volume of contrast agent while preserving diagnostic image quality. (orig.)

  2. Comparison of image quality and radiation dose between high-pitch mode and low-pitch mode spiral chest CT in small uncooperative children: The effect of respiratory rate

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    Kim, Seong Ho; Choi, Young Hun; Cho, Hyun-Hae; Lee, So Mi [Seoul National University Hospital, Seoul National University College of Medicine, Department of Radiology, Seoul (Korea, Republic of); Shin, Su-Mi [SMG-SNU Boramae Medical Center, Department of Radiology, Seoul (Korea, Republic of); Cheon, Jung-Eun; Kim, Woo Sun; Kim, In-One [Seoul National University Hospital, Seoul National University College of Medicine, Department of Radiology, Seoul (Korea, Republic of); Seoul National University Medical Research Center, Institute of Radiation Medicine, Seoul (Korea, Republic of)

    2016-04-15

    To compare image quality and radiation dose between high-pitch mode (HPM) and low-pitch mode (LPM) CT in young children. Forty-seven children (mean age 35.6 months; range, 0-126 months) underwent 49 CT examinations in HPM or LPM and were divided into high or low respiratory rate (RR) groups. A qualitative image quality was compared between the two modes. The volume CT dose index (CTDI{sub vol}) and dose-length product (DLP) were evaluated from the dose reports, and effective doses were assessed using a paediatric phantom. Image quality was generally better for HPM than LPM (diagnostic acceptance score, 4.00 vs. 3.46, P = 0.004); the difference was more prominent in the high RR group (4.00 vs. 3.22, P = 0.001). However, there was no significant difference in the low RR group. The mean DLP value was higher in HPM than LPM (29.48 mGy . cm vs. 23.46 mGy . cm, P = 0.022), while CTDI{sub vol} was not significantly different. The total effective radiation dose was 26 % higher in HPM than LPM (1.82 mSv vs. 1.44 mSv). LPM can be considered for paediatric lung evaluation in young children with low RRs to reduce radiation dose while maintaining favourable image quality. (orig.)

  3. High-frequency complex pitch

    DEFF Research Database (Denmark)

    Santurette, Sébastien; Dau, Torsten

    2012-01-01

    Harmonics in a complex tone are typically considered unresolved when they interact with neighboring harmonics in the cochlea and cannot be heard out separately. Recent studies have suggested that the low pitch evoked by unresolved high-frequency harmonics may be coded via temporal fine-structure ......Harmonics in a complex tone are typically considered unresolved when they interact with neighboring harmonics in the cochlea and cannot be heard out separately. Recent studies have suggested that the low pitch evoked by unresolved high-frequency harmonics may be coded via temporal fine......-structure cues. However, these conclusions rely on the assumptions that combination tones were properly masked and that the ability of listeners to hear out individual partials provides an adequate measure of resolvability. Those assumptions were tested by measuring the audibility of combination tones...... and their effects on pitch matches, the effects of relative component phases and of dichotic presentation, and listeners' ability to hear out individual partials. The results confirmed that combination tones affected pitch, but pitch remained salient when they were masked. The lack of dependence of pitch...

  4. Prospectively Electrocardiogram-Gated High-Pitch Spiral Acquisition Mode Dual-Source CT Coronary Angiography in Patients with High Heart Rates: Comparison with Retrospective Electrocardiogram-Gated Spiral Acquisition Mode

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    Sun, Kai; Ma, Rui; Wang, Li Jun [Dept. of Radiology, Baotou Central Hospital, Baotou (China); Li, Li Gang; Chen, Jiu Hong [CT BM Clinic Marketing, Siemens Healthcare, Beijing (China)

    2012-11-15

    To assess the image quality and effective radiation dose of prospectively electrocardiogram (ECG)-gated high-pitch spiral acquisition mode (flash mode) of dual-source CT (DSCT) coronary angiography (CTCA) in patients with high heart rates (HRs) as compared with retrospectively ECG-gated spiral acquisition mode. Two hundred and sixty-eight consecutive patients (132 female, mean age: 55 {+-} 11 years) with mean HR > 65 beats per minute (bpm) were prospectively included in this study. The patients were divided into two groups. Collection was performed in group A CTCA using flash mode setting at 20-30% of the R-R interval, and retrospectively ECG-gated spiral acquisition mode in group B. The image noise, contrast-to-noise ratio (CNR), image quality scores, effective radiation dose and influencing factors on image quality between the two groups were assessed. There were no significant differences in image quality scores and proportions of non-diagnostic coronary artery segments between two groups (image quality scores: 1.064 {+-} 0.306 [group A] vs. 1.084 {+-} 0.327 [group B], p = 0.063; proportion of non-diagnostic coronary artery segments: segment-based analysis 1.52% (group A) vs. 1.74% (group B), p = 0.345; patient-based analysis 7.5% (group A) vs. 6.7% (group B), p = 0.812). The estimated radiation dose was 1.0 {+-} 0.16 mSv in group A and 7.1 {+-} 1.05 mSv in group B (p = 0.001). In conclusion, in patients with HRs > 65 bpm without cardiac arrhythmia, the prospectively high-pitch spiral-acquisition mode with image-acquired timing set at 20-30% of the R-R interval provides a similar image quality and low rate of non-diagnostic coronary segments to the retrospectively ECG-gated low-pitch spiral acquisition mode, with significant reduction of radiation exposure.

  5. Effect of the high-pitch mode in dual-source computed tomography on the accuracy of three-dimensional volumetry of solid pulmonary nodules: A phantom study

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    Hwang, Sung Ho; Oh, Yu Whan; Ham, Soo Youn [Dept. of Radiology, Korea University Anam Hospital, Seoul (Korea, Republic of); Kang, Eun Young [Dept. of Radiology, Korea University Guro Hospital, Seoul (Korea, Republic of); Lee, Ki Yeol [Dept. of Radiology, Korea University Ansan Hospital, Ansan (Korea, Republic of)

    2015-06-15

    To evaluate the influence of high-pitch mode (HPM) in dual-source computed tomography (DSCT) on the accuracy of three-dimensional (3D) volumetry for solid pulmonary nodules. A lung phantom implanted with 45 solid pulmonary nodules (n = 15 for each of 4-mm, 6-mm, and 8-mm in diameter) was scanned twice, first in conventional pitch mode (CPM) and then in HPM using DSCT. The relative percentage volume errors (RPEs) of 3D volumetry were compared between the HPM and CPM. In addition, the intermode volume variability (IVV) of 3D volumetry was calculated. In the measurement of the 6-mm and 8-mm nodules, there was no significant difference in RPE (p > 0.05, respectively) between the CPM and HPM (IVVs of 1.2 +/- 0.9%, and 1.7 +/- 1.5%, respectively). In the measurement of the 4-mm nodules, the mean RPE in the HPM (35.1 +/- 7.4%) was significantly greater (p < 0.01) than that in the CPM (18.4 +/- 5.3%), with an IVV of 13.1 +/- 6.6%. However, the IVVs were in an acceptable range (< 25%), regardless of nodule size. The accuracy of 3D volumetry with HPM for solid pulmonary nodule is comparable to that with CPM. However, the use of HPM may adversely affect the accuracy of 3D volumetry for smaller (< 5 mm in diameter) nodule.

  6. Utility of dual source CT with ECG-triggered high-pitch spiral acquisition (Flash Spiral Cardio mode) to evaluate morphological features of ventricles in children with complex congenital heart defects.

    Science.gov (United States)

    Nakagawa, Motoo; Ozawa, Yoshiyuki; Nomura, Norikazu; Inukai, Sachiko; Tsubokura, Satoshi; Sakurai, Keita; Shimohira, Masashi; Ogawa, Masaki; Shibamoto, Yuta

    2016-04-01

    We evaluated the ability of dual source CT (DSCT) with ECG-triggered high-pitch spiral acquisition (Flash Spiral Cardio mode) to depict the morphological features of ventricles in pediatric patients with congenital heart defects (CHD). Between July 2013 and April 2015, 78 pediatric patients with CHD (median age 4 months) were examined using DSCT with the Flash Spiral Cardio mode. The types of ventricular abnormalities were ventricular septal defect (VSD) in 42 (the malaligned type in 11, perimembranous type in 23, supracristal type in 2, atrioventricular type in 2, and muscular type in 4), single ventricle (SV) in 11, and congenital corrected transposition of the great arteries (ccTGA) in 4. We evaluated the accuracy of the diagnosis of the VSD type. In cases of SV and ccTGA, we assessed the detectability of the anatomical features of both ventricles for a diagnosis of ventricular situs. DSCT confirmed the diagnoses for all VSDs. The type of defect was precisely diagnosed for all patients. The anatomical features of both ventricles were also depicted and ventricular situs of SV and ccTGA was correctly diagnosed. The results suggest that DSCT has the ability to clearly depict the configuration of ventricles.

  7. Adaptive sliding mode back-stepping pitch angle control of a variable-displacement pump controlled pitch system for wind turbines.

    Science.gov (United States)

    Yin, Xiu-xing; Lin, Yong-gang; Li, Wei; Liu, Hong-wei; Gu, Ya-jing

    2015-09-01

    A variable-displacement pump controlled pitch system is proposed to mitigate generator power and flap-wise load fluctuations for wind turbines. The pitch system mainly consists of a variable-displacement hydraulic pump, a fixed-displacement hydraulic motor and a gear set. The hydraulic motor can be accurately regulated by controlling the pump displacement and fluid flows to change the pitch angle through the gear set. The detailed mathematical representation and dynamic characteristics of the proposed pitch system are thoroughly analyzed. An adaptive sliding mode pump displacement controller and a back-stepping stroke piston controller are designed for the proposed pitch system such that the resulting pitch angle tracks its desired value regardless of external disturbances and uncertainties. The effectiveness and control efficiency of the proposed pitch system and controllers have been verified by using realistic dataset of a 750 kW research wind turbine. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

  8. When high pitches sound low: Children’s acquisition of space-pitch metaphors

    NARCIS (Netherlands)

    Dolscheid, S.J.; Hunnius, S.; Majid, A.; Noelle, D.C.; Dale, R.; Warlaumont, A.S.; Yoshimi, J.; Matlock, T.; Jennings, C.D.; Maglio, P.P.

    2015-01-01

    Some languages describe musical pitch in terms of spatial height; others in terms of thickness. Differences in pitch metaphors also shape adults’ nonlinguistic space-pitch representations. At the same time, 4-month-old infants have both types of space-pitch mappings available. This tension between

  9. Voice examination in patients with decreased high pitch after thyroidectomy.

    Science.gov (United States)

    Kim, Sung Won; Kim, Seung Tae; Park, Hyo Sang; Lee, Hyoung Shin; Hong, Jong Chul; Kwon, Soon Bok; Lee, Kang Dae

    2012-06-01

    Decreased high pitch after thyroidectomy due to injury of the external branch of superior laryngeal nerve (EBSLN) may be a critical, especially to professional voice users. The author studied the usefulness of VRP (voice range profile) and MDVP (multi-dimensional voice program) to evaluate patients who have decreased high pitch after thyroidectomy. A study was performed with 58 females and 9 males who underwent voice assessment between January 2008 and June 2009. The patients were classified as the group of female with no decreased high pitch (group A, n = 52), decreased high pitch (group B, n = 6) and the group of male with no decreased high pitch (group C, n = 9). VRP and laryngeal electromyogram (EMG) was performed in group B. The preoperative frequency range of group A and B were statistically not different. In Group B, the result of VRP showed that the frequency range was 443.11 ± 83.97, 246.67 ± 49.41, 181.37 ± 80.13 Hz showing significant decrease after the surgery compared to that of the preoperative result. (P VRP revealed no significant difference between the preoperative and postoperative result. VRP is a noninvasive, quick, and practical test to demonstrate decreased frequency range visually and helps to evaluate EBSLN injury in patient with thyroidectomy.

  10. Preliminary evaluation of ultra-high pitch computed tomography enterography

    Energy Technology Data Exchange (ETDEWEB)

    Hardie, Andrew D.; Horst, Nicole D.; Mayes, Nicholas [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston (United States)], E-mail: andrewdhardie@gmail.com

    2012-12-15

    Background. CT enterography (CTE) is a valuable tool in the management of patients with inflammatory bowel disease. Reducing imaging time, reduced motion artifacts, and decreased radiation exposure are important goals for optimizing CTE examinations. Purpose. To assess the potential impact of new CT technology (ultra-high pitch CTE) for the ability to reduce scan time and also potentially reduce radiation exposure while maintaining image quality. Material and Methods. This retrospective study compared 13 patients who underwent ultra-high pitch CTE with 25 patients who underwent routine CTE on the same CT scanner with identical radiation emission settings. Total scan time and radiation exposure were recorded for each patient. Image quality was assessed by measurement of image noise and also qualitatively by two independent observers. Results. Total scan time was significantly lower for patients who underwent ultra-high pitch CTE (2.1 s {+-} 0.2) than by routine CTE (18.6 s {+-} 0.9) (P < 0.0001). The mean radiation exposure for ultra-high pitch CTE was also significantly lower (10.1 mGy {+-} 1.0) than routine CTE (15.8 mGy {+-} 4.5) (P < 0.0001). No significant difference in image noise was found between ultra-high pitch CTE (16.0 HU {+-} 2.5) and routine CTE (15.5 HU {+-} 3.7) (P > 0.74). There was also no significant difference in image quality noted by either of the two readers. Conclusion. Ultra-high pitch CTE can be performed more rapidly than standard CTE and offers the potential for radiation exposure reduction while maintaining image quality.

  11. High-pitch dual-source CT coronary angiography: systolic data acquisition at high heart rates

    Energy Technology Data Exchange (ETDEWEB)

    Goetti, Robert; Feuchtner, Gudrun; Desbiolles, Lotus; Fischer, Michael Alexander; Karlo, Christoph; Baumueller, Stephan [University Hospital Zurich, Institute of Diagnostic Radiology, Zurich (Switzerland); Stolzmann, Paul; Scheffel, Hans; Alkadhi, Hatem [University Hospital Zurich, Institute of Diagnostic Radiology, Zurich (Switzerland); Massachusetts General Hospital and Harvard Medical School, Cardiac MR PET CT Program, Boston, MA (United States); Leschka, Sebastian [University Hospital Zurich, Institute of Diagnostic Radiology, Zurich (Switzerland); Kantonsspital St. Gallen, Institute of Radiology, St. Gallen (Switzerland)

    2010-11-15

    To assess the effect of systolic data acquisition for electrocardiography (ECG)-triggered high-pitch computed tomography (CT) on motion artefacts of coronary arteries in patients with high heart rates (HRs). Eighty consecutive patients (15 women, age 67 {+-} 14 years) with HR {>=}70 bpm underwent CT angiography of the thoracic aorta (CTA) on 128-slice dual-source CT in ECG-triggered high-pitch acquisition mode (pitch = 3.2) set at 60% (group A, n = 40) or 30% (group B, n = 40) of the RR interval. Two blinded readers graded coronary artery image quality on a three-point scale. Radiation doses were calculated. Inter-observer agreement in grading image quality of the 1,154 coronary segments was good ({kappa} = 0.62). HRs were similar in groups A and B (85 {+-} 13 bpm vs 85 {+-} 14 bpm, p not significant). Significantly fewer coronary segments with non-diagnostic image quality occurred (i.e. score 3) in group B than in group A [2.8% (16/579) vs 8.3% (48/575), p < 0.001]. Seventeen patients (42.5%) of group A and 12 patients (30.0%) of group B had at least one non-diagnostic segment. Effective radiation doses were 2.3 {+-} 0.3 mSv for chest CTA. A systolic acquisition window for high-pitch dual-source CTA in patients with high HRs ({>=}70 bpm) significantly improves coronary artery image quality at a low radiation dose. (orig.)

  12. Efficacy of high-pitch CT protocols for radiation dose reduction.

    Science.gov (United States)

    Guberina, N; Lechel, U; Forsting, M; Ringelstein, A

    2016-12-01

    Various strategies have been developed to reduce radiation exposure of patients in CT examinations. The aim of this study was to evaluate the efficacy of high pitch in representative CT protocols examining lung embolism. We performed thermoluminescence measurements with an anthropomorphic phantom exposing it to CT algorithms for lung embolism in a 128-multislice, dual-source CT scanner: a standard CT protocol (sCT) and a CT protocol with a high pitch (+ F). Radiation doses for both CT algorithms were compared and the dose reduction potential of high pitch for individual organs was evaluated. As expected, the  +F mode reduced the effective dose and organ doses in the primary beam of radiation (namely, lung, bone marrow, heart, breast, skin and skeleton) compared with sCT by up to 52% for an equivalent image quality. On the contrary, for organs at the margin of the primary beam (thymus, thyroid, liver, pancreas, kidneys, colon and small intestine), the  +F mode reduced effective radiation doses by only 0-30%, compared with sCT. The dose reduction potential of the  +F mode greatly depends on the position of the organ in the scan field. While for organs in the primary beam  + F leads to a considerable dose reduction, it is less effective for tissues at the margin of the scanned area.

  13. Visuoauditory mappings between high luminance and high pitch are shared by chimpanzees (Pan troglodytes) and humans

    Science.gov (United States)

    Ludwig, Vera U.; Adachi, Ikuma; Matsuzawa, Tetsuro

    2011-01-01

    Humans share implicit preferences for certain cross-sensory combinations; for example, they consistently associate higher-pitched sounds with lighter colors, smaller size, and spikier shapes. In the condition of synesthesia, people may experience such cross-modal correspondences to a perceptual degree (e.g., literally seeing sounds). So far, no study has addressed the question whether nonhuman animals share cross-modal correspondences as well. To establish the evolutionary origins of cross-modal mappings, we tested whether chimpanzees (Pan troglodytes) also associate higher pitch with higher luminance. Thirty-three humans and six chimpanzees were required to classify black and white squares according to their color while hearing irrelevant background sounds that were either high-pitched or low-pitched. Both species performed better when the background sound was congruent (high-pitched for white, low-pitched for black) than when it was incongruent (low-pitched for white, high-pitched for black). An inherent tendency to pair high pitch with high luminance hence evolved before the human lineage split from that of chimpanzees. Rather than being a culturally learned or a linguistic phenomenon, this mapping constitutes a basic feature of the primate sensory system. PMID:22143791

  14. High-pitch metal-on-glass technology for pad pitch adaptation between detectors and readout electronics

    CERN Document Server

    Ullán, Miguel; Campabadal, Francesca; Fleta, Celeste; Garcia, Carmen; Gonzalez, Francisco; Bernabeu, Jose

    2004-01-01

    Modern high-energy physics and astrophysics strip detectors have increased channel density to levels at which their connection with readout electronics has become very complex due to high pad pitch. Also, direct wire bonding is prevented by the fact that typically detector's pad pitch and electronics' pad pitch do not match. A high- pitch metal-on-glass technology is presented, that allows pad pitch adaptation between detectors and readout electronics. It consists of high-density metal lines on top of an insulating glass substrate. A photoresist layer is deposited covering the metal tracks for passivation and protection The technology is tested for conductivity, bondability, bonding pull force, peel off, and radiation hardness, and it is an established technology in the clean room of the CNM Institute in Barcelona. This technology has been chosen by the ATLAS Collaboration for the pad pitch adapters (PPA) of the SCT Endcap Modules, by a Compton camera project, and by other HEP groups for interconnection betwe...

  15. Absolute pitch correlates with high performance on musical dictation.

    Science.gov (United States)

    Dooley, Kevin; Deutsch, Diana

    2010-08-01

    Absolute pitch (AP)--the ability to name a musical note in the absence of a reference note--is a rare ability whose relevance to musical proficiency has so far been unclear. Sixty trained musicians--thirty who self-reported AP and thirty with equivalent age of onset and duration of musical training--were administered a test for AP and also a musical dictation test not requiring AP. Performance on both types of test were highly correlated (r=.81, pdictation test, the scores of those without AP varied widely, and the performance of the intermediate group of borderline AP possessors fell between that of clear AP possessors and clear nonpossessors. The findings support the hypothesis that AP is associated with proficiency in performing other musical tasks, and run counter to the claim that it confers a disadvantage in the processing of relative pitch.

  16. Preferences for very low and very high voice pitch in humans.

    Directory of Open Access Journals (Sweden)

    Daniel E Re

    Full Text Available Manipulations of voice pitch have been shown to alter attractiveness ratings, but whether preferences extend to very low or very high voice pitch is unknown. Here, we manipulated voice pitch in averaged men's and women's voices by 2 Hz intervals to create a range of male and female voices speaking monopthong vowel sounds and spanning a range of frequencies from normal to very low and very high pitch. With these voices, we used the method of constant stimuli to measure preferences for voice. Nineteen university students (ages: 20-25 participated in three experiments. On average, men preferred high-pitched women's voices to low-pitched women's voices across all frequencies tested. On average, women preferred men's voices lowered in pitch, but did not prefer very low men's voices. The results of this study may reflect selection pressures for men's and women's voices, and shed light on a perceptual link between voice pitch and vocal attractiveness.

  17. Preferences for very low and very high voice pitch in humans.

    Science.gov (United States)

    Re, Daniel E; O'Connor, Jillian J M; Bennett, Patrick J; Feinberg, David R

    2012-01-01

    Manipulations of voice pitch have been shown to alter attractiveness ratings, but whether preferences extend to very low or very high voice pitch is unknown. Here, we manipulated voice pitch in averaged men's and women's voices by 2 Hz intervals to create a range of male and female voices speaking monopthong vowel sounds and spanning a range of frequencies from normal to very low and very high pitch. With these voices, we used the method of constant stimuli to measure preferences for voice. Nineteen university students (ages: 20-25) participated in three experiments. On average, men preferred high-pitched women's voices to low-pitched women's voices across all frequencies tested. On average, women preferred men's voices lowered in pitch, but did not prefer very low men's voices. The results of this study may reflect selection pressures for men's and women's voices, and shed light on a perceptual link between voice pitch and vocal attractiveness.

  18. Two Studies of Pitch in String Instrument Vibrato: Perception and Pitch Matching Responses of University and High School String Players

    Science.gov (United States)

    Geringer, John M.; MacLeod, Rebecca B.; Ellis, Julia C.

    2014-01-01

    We investigated pitch perception of string vibrato tones among string players in two separate studies. In both studies we used tones of acoustic instruments (violin and cello) as stimuli. In the first, we asked 192 high school and university string players to listen to a series of tonal pairs: one tone of each pair was performed with vibrato and…

  19. Preferences for Very Low and Very High Voice Pitch in Humans

    OpenAIRE

    Daniel E Re; Jillian J M O'Connor; Bennett, Patrick J.; Feinberg, David R.

    2012-01-01

    Manipulations of voice pitch have been shown to alter attractiveness ratings, but whether preferences extend to very low or very high voice pitch is unknown. Here, we manipulated voice pitch in averaged men's and women's voices by 2 Hz intervals to create a range of male and female voices speaking monopthong vowel sounds and spanning a range of frequencies from normal to very low and very high pitch. With these voices, we used the method of constant stimuli to measure preferences for voice. N...

  20. A Pitch Extraction Method with High Frequency Resolution for Singing Evaluation

    Science.gov (United States)

    Takeuchi, Hideyo; Hoguro, Masahiro; Umezaki, Taizo

    This paper proposes a pitch estimation method suitable for singing evaluation incorporable in KARAOKE machines. Professional singers and musicians have sharp hearing for music and singing voice. They recognize that singer's voice pitch is “a little off key” or “be in tune”. In the same way, the pitch estimation method that has high frequency resolution is necessary in order to evaluate singing. This paper proposes a pitch estimation method with high frequency resolution utilizing harmonic characteristic of autocorrelation function. The proposed method can estimate a fundamental frequency in the range 50 ∼ 1700[Hz] with resolution less than 3.6 cents in light processing.

  1. Perceptual confusions of high-pitched sung vowels.

    Science.gov (United States)

    Hollien, H; Mendes-Schwartz, A P; Nielsen, K

    2000-06-01

    Questions exist as to the intelligibility of vowels sung at extremely high fundamental frequencies and, especially, when the fundamental frequency (F0) produced is above the region where the first vowel formant (F1) would normally occur. Can such vowels be correctly identified and, if so, does context provide the necessary information or are acoustical elements also operative? To this end, 18 professional singers (5 males and 13 females) were recorded when singing 3 isolated vowels at high and low pitches at both loud and soft levels. Aural-perceptual studies employing four types of auditors were carried out to determine the identity of these vowels, and the nature of the confusions with other vowels. Subsequent acoustical analysis focused on the actual fundamental frequencies sung plus those defining the first 2 vowel formants. It was found that F0 change had a profound effect on vowel perception; one of the more important observations was that the target tended to shift toward vowels with an F1 just above the sung frequency.

  2. Ultra-fine pitch individually addressable visible laser arrays for high speed digital printing applications

    Science.gov (United States)

    Kowalski, O. P.; McDougall, S. D.; Qiu, B. C.; Masterton, G. H.; Armstrong, M. L.; Robertson, S.; Caldecott, S.; Marsh, J. H.

    2009-02-01

    An individually addressable visible semiconductor laser diode array with a 20 μm pitch is demonstrated that is highly suited for deployment in next-generation digital print systems. The array, operating at 660 nm, comprises 22 single mode lasers fabricated on a single GaInP/AlGaInP/GaAs substrate. The laser array is flip-chip bonded onto a patterned ceramic submount that enables the individual elements to be driven independently and is integrated into a 26-pin butterfly package. Arrays tested CW exhibit low threshold current (<20 mA per emitter), up to 50 mW output power per channel with a high slope efficiency (0.9 W/A) and a high characteristic temperature of over 100 K.

  3. The Pitch-Matching Ability of High School Choral Students: A Justification for Continued Direct Instruction

    Science.gov (United States)

    Riegle, Aaron M.; Gerrity, Kevin W.

    2011-01-01

    The purpose of this study was to determine the pitch-matching ability of high school choral students. Years of piano experience, middle school performance experience, and model were considered as variables that might affect pitch-matching ability. Gender of participants was also considered when identifying the effectiveness of each model.…

  4. Cardiac spiral dual-source CT with high pitch: a feasibility study.

    Science.gov (United States)

    Ertel, Dirk; Lell, Michael M; Harig, Frank; Flohr, Thomas; Schmidt, Bernhard; Kalender, Willi A

    2009-10-01

    Increase of pitch in spiral CT decreases data acquisition time; dual-source CT (DSCT) systems provide improved temporal resolution. We evaluated the combination of these two features. Measurements were performed using a commercial DSCT system equipped with prototype software allowing pitch factors from p = 0.35 to 3.0. We measured slice sensitivity profiles as a function of pitch to assess spatial resolution in the z-direction and the contrast of structures moved periodically to measure temporal resolution. Additionally we derived modulation transfer functions to provide objective parameters; both spatial and temporal resolution were essentially unchanged even at high pitch. CT of the cardiac region of three pigs was performed at p = 3.0. In vivo CT images confirmed good image quality; direct comparison with standard low-pitch phase-correlated CT image datasets showed no significant difference. For a normalized z-axis acquisition of 12 cm, the corresponding effective dose value was 2.0 mSv for the high-pitch CT protocol. We conclude that spiral DSCT imaging with a pitch of 3.0 can provide unimpaired image quality with respect to spatial and temporal resolution. Applications to cardiac and thoracic imaging with effective dose below 1 mSv are possible.

  5. Accuracy, image quality and radiation dose comparison of high-pitch spiral and sequential acquisition on 128-slice dual-source CT angiography in children with congenital heart disease.

    Science.gov (United States)

    Nie, Pei; Wang, Ximing; Cheng, Zhaoping; Ji, Xiaopeng; Duan, Yanhua; Chen, Jiuhong

    2012-10-01

    To compare accuracy, image quality and radiation dose between high-pitch spiral and sequential modes on 128-slice dual-source computed tomographic (DSCT) angiography in children with congenital heart disease (CHD). Forty patients suspected with CHD underwent 128-slice DSCT angiography with high-pitch mode and sequential mode respectively. All the anomalies were confirmed by the surgical and/or the conventional cardiac angiography (CCA) findings. The diagnostic accuracy, the subjective and objective image quality and effective radiation doses were compared. There was no significant difference in diagnostic accuracy (χ ( 2 ) = 0.963, P > 0.05), the objective parameters for image quality (P > 0.05) and the image quality of great vessels (u = 167.500, P > 0.05) between the two groups. The image quality of intracardiac structures and coronary arteries was significantly better in the sequential mode group than that in the high-pitch group (u = 112.500 and 100.000, P < 0.05). The mean effective dose in high-pitch group (0.17 ± 0.05 mSv) was significantly lower (t = 5.287, P < 0.05) than that in the sequential mode group (0.29 ± 0.09 mSv). Both the high-pitch and the sequential modes for 128-slice DSCT angiography provide high accuracy for the assessment of CHD in children, while the high-pitch mode, even with some image quality decrease, further significantly lowers the radiation dose. • Modern CT provides excellent anatomical detail of congenital heart disease. • Dual source CT systems offer high-pitch spiral and sequential modes. • The high-pitch mode provides high accuracy for the assessment of CHD. • A few images using the high-pitch mode were occasionally slightly degraded. • But the high-pitch mode significantly lowers the radiation dose.

  6. High-power single-frequency pulsed laser based on a Yb-doped large-pitch photonic crystal fiber

    Science.gov (United States)

    Cha, Yong-Ho; Kim, Yonghee; Park, Hyunmin; Lim, Gwon; Ko, Kwang-Hoon; Kim, Taek Soo; Jeong, Do-Young

    2017-06-01

    We have developed a high-power single-frequency pulsed fiber laser system utilizing a Yb-doped rod-type large-pitch photonic crystal fiber. The maximal peak power is 33 kW with a 0.4-mJ pulse energy and a 70-MHz linewidth, and the average power is 60 W at a 150-kHz repetition rate. At a higher repetition rate, the average power can be increased to 190 W, which is limited by the onset of transverse-mode instability in the large-pitch photonic crystal fiber. The output beam is linearly polarized and shows a good beam quality with a M2 value of 1.2.

  7. Delayed enhancement imaging of myocardial viability: low-dose high-pitch CT versus MRI

    Energy Technology Data Exchange (ETDEWEB)

    Goetti, Robert; Feuchtner, Gudrun; Stolzmann, Paul; Donati, Olivio F.; Frauenfelder, Thomas; Leschka, Sebastian; Alkadhi, Hatem [University Hospital Zurich, Department of Radiology, Zurich (Switzerland); Wieser, Monika; Plass, Andre [University Hospital Zurich, Division of Cardiac and Vascular Surgery, Zurich (Switzerland)

    2011-10-15

    To evaluate the accuracy of high-pitch delayed enhancement (DE) CT for the assessment of myocardial viability with MRI as the reference standard. Twenty-four patients (mean age 66.9 {+-} 9.2 years) with coronary artery disease underwent DE imaging with 128-slice dual-source CT (prospective electrocardiography (ECG)-triggering) and MRI at 1.5 T. Two observers assessed DE transmurality per segment, and measured signal intensity (MRI) or attenuation (CT) in infarcted and healthy myocardium and noise in the left ventricular blood pool for calculating contrast-to-noise ratios (CNR). 75/408 (18.4%) segments in 18/24 patients (75.0%) showed DE in MRI, of which 28 segments in 10/24 (41.7%) patients were non-viable (scar tissue transmurality >50%). Sensitivity, specificity and accuracy of CT for diagnosis of non-viability were 60.7%, 96.8% and 94.4% per segment, and 90.0%, 92.9% and 91.7% per patient. CNR was significantly higher in MR (7.4 {+-} 3.0 vs. 4.6 {+-} 1.5; p = 0.018), and image noise significantly lower (11.6 {+-} 5.7 vs.15.0 {+-} 4.5; p = 0.019). Radiation dose of DECT was 0.89 {+-} 0.07 mSv. CTDE imaging in the high-pitch mode enables myocardial viability assessment at a low radiation dose and good accuracy compared with MR, although associated with a lower CNR and higher noise. (orig.)

  8. Exploration of coal-based pitch precursors for ultra-high thermal conductivity graphite fibers. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Deshpande, G.V. [Amoco Performance Products, Inc., Alpharetta, GA (United States)

    1996-12-27

    Goal was to explore the utility of coal-based pitch precursors for use in ultra high thermal conductivity carbon (graphite) fibers. From graphite electrode experience, it was established that coal-based pitches tend to form more highly crystalline graphite at lower temperatures. Since the funding was limited to year 1 effort of the 3 year program, the goal was only partially achieved. The coal-base pitches can form large domain mesophase in spite of high N and O contents. The mesophase reactivity test performed on one of the variants of coal-based pitch (DO84) showed that it was not a good candidate for carbon fiber processing. Optimization of WVU`s isotropic pitch process is required to tailor the pitch for carbon fiber processing. The hetero atoms in the coal pitch need to be reduced to improve mesophase formation.

  9. Clinical utility of ultra high pitch dual source thoracic CT imaging of acute pulmonary embolism in the emergency department: Are we one step closer towards a non-gated triple rule out?

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Daniel J., E-mail: danieljameshou@gmail.com; Tso, David K., E-mail: david.k.tso@gmail.com; Davison, Chris, E-mail: chrisdavison100@gmail.com; Inacio, Joao, E-mail: joao.r.inacio@gmail.com; Louis, Luck J., E-mail: lucklouis@gmail.com; Nicolaou, Savvakis, E-mail: savvas.nicolaou@vch.ca; Reimann, Anja J., E-mail: anja.reimann@gmx.de

    2013-10-01

    Objectives/Purpose: Aim of this study was to retrospectively compare the image quality and the radiation dose of an ultra high pitch CT scan for the evaluation of pulmonary embolism and visualization of cardiac structures in comparison to our institution's standard pulmonary embolism protocol. Method and materials: The study cohort consisted of 115 consecutive patients, 57 underwent CT pulmonary angiography on a dual source 128 slice scanner (Siemens Somatom Definition FLASH) via an ultra high pitch mode (Pitch 2.8) while 58 were scanned on a dual source 64 slice scanner (Siemens Somatom Definition Dual Source) with standard pitch (Pitch 0.9). Qualitative image assessment was determined by two blinded radiologists with 3 and 15 years’ experience in chest and cardiac CT. Quantitative image assessment was determined by the signal to noise ratio (SNR) and contrast to noise ratio (CNR). Effective radiation dose was calculated via the product of the dose length product. Results: For the ultra high pitch protocol, 14% (8/57) were positive for pulmonary embolus compared to 13.7% (8/58) for the standard pitch group. 98.2% of the ultra high pitch scans were diagnostic for pulmonary embolus vs. 94.8% of the standard protocol. Visualization of cardiac structures was significantly improved with the ultra high pitch protocol (p < 0.0001). Significantly more lung parenchymal motion was observed on the standard protocol (p < 0.0001). The mean pulmonary vessel attenuation, SNR, and CNR were not significantly different. The mean effective dose was lower for the ultra high pitch studies (4.09 mSv ± 0.78 vs. 7.72 mSv ± 2.60, p < 0.0001). Conclusion: Ultra high pitch CT imaging for pulmonary embolus is a technique which has potential to assess motion free evaluation of most cardiac structures and proximal coronary arteries at lower radiation doses.

  10. Window anterior commissure relaxation laryngoplasty in the management of high-pitched voice disorders.

    Science.gov (United States)

    Kocak, Ismail; Dogan, Muzeyyen; Tadihan, Elcin; Alkan Cakir, Zeynep; Bengisu, Serkan; Akpinar, Meltem

    2008-12-01

    To present the success rate of a less invasive modification of Isshiki type III anterior commissure relaxation laryngoplasty technique in patients with high-pitched voice disorders. Prospective case series. KBB Major Private Clinic of Istanbul Surgery Hospital and the University of Yeditepe Hospital. Twenty-one adult patients who believed that their high-pitched voices conflicted with their body image and/or gender identity. Type III thyroplasty for pitch alteration. Comparison of preoperative and postoperative (>6 months) fundamental frequency levels, diplophonia, perception of body image and pitch, and subjective ratings of comfort during vocalization. The patients were mostly male (mean age, 30.5 years). The most frequent cause of high-pitched voice was sulcus vocalis (n = 14), followed by constitutional causes (n = 5), mutational falsetto (n = 1), and severe glottic scarring secondary to childhood diphtheria (n = 1). After surgery, the fundamental frequency dropped significantly from a mean of 213.81 Hz to 149.86 Hz (P < .001), equaling a mean postoperative semitone drop of 6.23. Misperception leading to an abnormal body image was reduced by 86%. Fourteen patients who originally had feelings of tension and fatigue during phonation and vocalization gained comfort postoperatively. Diplophonia with subharmonic signals observed in 11 cases preoperatively was reduced or disappeared in 6 cases. No complications or failures were observed during the follow-up period. Window anterior commissure relaxation laryngoplasty is an efficient, easy, less invasive, and safe procedure in the surgical management of organic and functional high-pitched voice disorders.

  11. Accuracy, image quality and radiation dose comparison of high-pitch spiral and sequential acquisition on 128-slice dual-source CT angiography in children with congenital heart disease

    Energy Technology Data Exchange (ETDEWEB)

    Nie, Pei; Wang, Ximing; Cheng, Zhaoping; Ji, Xiaopeng; Duan, Yanhua [Shandong University, Shandong Provincial Key Laboratory of Diagnosis and Treatment of Cardio-cerebral Vascular Diseases, Shandong Medical Imaging Research Institute, Jinan, Shandong (China); Chen, Jiuhong [CT Research Collaboration, Siemens Ltd. China, Beijing (China)

    2012-10-15

    To compare accuracy, image quality and radiation dose between high-pitch spiral and sequential modes on 128-slice dual-source computed tomographic (DSCT) angiography in children with congenital heart disease (CHD). Forty patients suspected with CHD underwent 128-slice DSCT angiography with high-pitch mode and sequential mode respectively. All the anomalies were confirmed by the surgical and/or the conventional cardiac angiography (CCA) findings. The diagnostic accuracy, the subjective and objective image quality and effective radiation doses were compared. There was no significant difference in diagnostic accuracy ({chi}{sup 2} = 0.963, P > 0.05), the objective parameters for image quality (P > 0.05) and the image quality of great vessels (u = 167.500, P > 0.05) between the two groups. The image quality of intracardiac structures and coronary arteries was significantly better in the sequential mode group than that in the high-pitch group (u = 112.500 and 100.000, P < 0.05). The mean effective dose in high-pitch group (0.17 {+-} 0.05 mSv) was significantly lower (t = 5.287, P < 0.05) than that in the sequential mode group (0.29 {+-} 0.09 mSv). Both the high-pitch and the sequential modes for 128-slice DSCT angiography provide high accuracy for the assessment of CHD in children, while the high-pitch mode, even with some image quality decrease, further significantly lowers the radiation dose. (orig.)

  12. The role of temporal fine structure information for the low pitch of high-frequency complex tones

    DEFF Research Database (Denmark)

    Santurette, Sébastien; Dau, Torsten

    2011-01-01

    in their waveforms, rather than envelope maxima. Moreover, envelope cues did not take over as the absolute frequency or rank of the lowest component was raised and TFS cues thus became less effective. Instead, the low pitch became less salient. This suggests that complex pitch perception does not rely on envelope......The fused low pitch evoked by complex tones containing only unresolved high-frequency components demonstrates the ability of the human auditory system to extract pitch using a temporal mechanism in the absence of spectral cues. However, the temporal features used by such a mechanism have been...... amplitude fluctuations, or temporal fine structure (TFS), of the conveyed signal can be processed. Using a pitch-matching paradigm, the present study found that the low pitch of inharmonic transposed tones with unresolved components was consistent with the timing between the most prominent TFS maxima...

  13. Acoustic analysis of voice in normal and high pitch phonation: a comparative study.

    Science.gov (United States)

    Aithal, Venkataraja U; Bellur, Rajashekhar; John, Sunila; Varghese, Ciji; Guddattu, Vasudeva

    2012-01-01

    Comparison of acoustic parameters of voice between normal and high pitch phonation in normal adults, and comparison between genders. A total of 48 normal laryngeal speakers were considered for this study. The acoustic parameters were analyzed using the Multi-Dimensional Voice Program. Descriptive statistics were used for analysis of the acoustic parameters across tasks and genders. Paired-samples t tests were used to compare measures between tasks. Independent-samples t tests were used to compare parameters between genders. Significant differences were found across tasks in the range of fundamental frequency and average fundamental frequency. Females showed a significant difference in the frequency perturbation measures – percent jitter and relative average perturbation, while males demonstrated a significant difference in the noise-to-harmonic ratio. While comparing mean differences between genders, significant differences were observed in fundamental frequency, range of the fundamental frequency, and smoothed pitch perturbation quotient during both phonation tasks. Comparison of acoustic parameters between normal and high pitch phonation would facilitate understanding the effect of high pitch phonation on voice parameters. Subsequently, this would help clinicians to focus on important acoustic parameters while assessing professional voice users who are at risk of developing voice problems.

  14. High-energy scissors mode

    Energy Technology Data Exchange (ETDEWEB)

    Nojarov, R.; Faessler, A.; Dingfelder, M. [Institut fuer Theoretische Physik, Universitaet Tuebingen, Auf der Morgenstelle 14, D-72076 Tuebingen (Germany)

    1995-05-01

    All the orbital {ital M}1 excitations, at both low and high energies, obtained from a rotationally invariant quasiparticle random-phase approximation, represent the fragmented scissors mode. The high-energy {ital M}1 strength is almost purely orbital and resides in the region of the isovector giant quadrupole resonance. In heavy deformed nuclei the high-energy scissors model is strongly fragmented between 17 and 25 MeV (with uncertainties arising from the poor knowledge of the isovector potential). The coherent scissors motion is hindered by the fragmentation and {ital B}({ital M}1){lt}0.25{mu}{sub {ital N}}{sup 2} for single transitions in this region. The ({ital e},{ital e}{prime}) cross sections for excitations above 17 MeV are one order of magnitude larger for {ital E}2 than for {ital M}1 excitations even at backward angles.

  15. Whole-Body High-Pitch CT Angiography: Strategies to Reduce Radiation Dose and Contrast Volume.

    Science.gov (United States)

    Manneck, Sebastian; Hurwitz, Lynne M; Seaman, Danielle M; Heye, Tobias; Boll, Daniel T

    2017-10-05

    The purpose of this study was to assess the noninferiority of dual-source high-pitch CT angiography (CTA) performed with high-concentration (iopamidol 370) low-volume (60 mL) iodinated contrast material at low voltage (100 kVp) in comparison with dual-source high-pitch CTA with standard-of-care low-concentration (iopamidol 300) standard-volume (75 mL) iodinated contrast material at high voltage (120 kVp) to determine whether use of the high-concentration low-volume method would afford a reduction in radiation dose and contrast volume without negatively affecting vascular opacification. This study had three arms. A phantom was used to assess vascular contrast enhancement at different iodine and saline solution dilutions with iopamidol 300 or 370 to compare lower-iodination (iopamidol 300) high-voltage (120 kVp) high-pitch (120 kVp, 250 mAs) imaging with higher-iodination (iopamidol 370) low-voltage (100 kVp) high-pitch (100 kVp, 100-240 mAs) acquisition. Metal-oxide-semiconductor field-effect transistors were placed in an anthropomorphic phantom to extract organ-based radiation profiles, and ANOVA was performed. The study prospectively enrolled 150 patients: 50 patients received 75 mL iopamidol 300, and image acquisition was performed at 120 kVp and 250 mAs; 50 patients received 75 mL iopamidol 370, and acquisition was performed at 100 kVp and 240 mAs; and 50 patients received 60 mL iopamidol, and acquisition was performed at 370 at 100 kVp and 240 mAs. Vascular signal-to-noise ratio was evaluated at 18 anatomic locations. Longitudinal signal-to-noise ratio was used to assess homogeneity of contrast enhancement. Size-specific dose estimates were calculated. Statistical analyses were performed by ANOVA. Noninferiority of high-concentration (iopamidol 370) low-voltage (100 kVp) high-pitch acquisitions compared with low-concentration (iopamidol 300) high-voltage (120 kVp) high-pitch acquisition was achieved at 170 mAs in vitro. Radiation assessment showed significant

  16. Evaluation of Advanced Bionics high resolution mode.

    Science.gov (United States)

    Buechner, Andreas; Frohne-Buechner, Carolin; Gaertner, Lutz; Lesinski-Schiedat, Anke; Battmer, Rolf-Dieter; Lenarz, Thomas

    2006-07-01

    The objective of this paper is to evaluate the advantages of the Advanced Bionic high resolution mode for speech perception, through a retrospective analysis. Forty-five adult subjects were selected who had a minimum experience of three months' standard mode (mean of 10 months) before switching to high resolution mode. Speech perception was tested in standard mode immediately before fitting with high resolution mode, and again after a maximum of six months high resolution mode usage (mean of two months). A significant improvement was found, between 11 and 17%, depending on the test material. The standard mode preference does not give any indication about the improvement when switching to high resolution. Users who are converted within any study achieve a higher performance improvement than those converted in the clinical routine. This analysis proves the significant benefits of high resolution mode for users, and also indicates the need for guidelines for individual optimization of parameter settings in a high resolution mode program.

  17. Octave Bias in Pitch Perception: The Influence of Pitch Height on Pitch Class Identification.

    Science.gov (United States)

    Prpic, Valter; Murgia, Mauro; De Tommaso, Matteo; Boschetti, Giulia; Galmonte, Alessandra; Agostini, Tiziano

    2016-09-01

    Pitch height and pitch class are different, but strictly related, percepts of music tones. To investigate the influence of pitch height in a pitch class identification task, we systematically analyzed the errors-in terms of direction and amount-committed by a group of musicians. The aim of our study was to verify the existence of constant errors in the identification of pitch classes across consecutive octaves. Stimuli were single piano tones from the C major scale executed in two consecutive octaves. Participants showed different response patterns in the two octaves. The direction of errors revealed a constant tendency to underestimate pitch classes in the lowest octave and to overestimate pitch classes in the highest octave. Thus, pitch height showed to influence pitch class identification. We called this bias "pitch class polarization", since the same pitch class was judged to be respectively lower and higher, depending on relatively low or high pitch height. © The Author(s) 2016.

  18. Carbonization and liquid-crystal (mesophase) development. 20. Co-carbonization of a high-volatile caking coal with several petroleum pitches

    Energy Technology Data Exchange (ETDEWEB)

    Grint, A.; Marsh, H.

    1981-06-01

    A high-volatile caking coal and five petroleum pitches were carbonized singly and coal/pitch systems were co-carbonized to 1273 K in the ratio of 75 wt% coal and 25 wt% pitch. Optical textures of cokes from the single carbonizations and co-carbonizations are assessed in terms of modification to the coal-coke by the pitch and unmodified pitch-coke using a point-counting technique. The pitches differ considerably in their carbonization behaviour. Each pitch can be placed into one of three groups defined in terms of their interaction with the high-volatile caking coal. A passive pitch does not modify the coal-coke but apparently carbonizes independently of the coal. An active pitch modified some of the coal-coke. No pitch-coke can be detected. A super-active pitch modifies the coal-coke extensively beyond the extent expected from a 25% addition. No pitch-coke can be detected. The effects are related to the ability of the pitch to cause depolymerization of the coal. Quinoline-insoluble material in pitch may inhibit modification. (8 refs.)

  19. Force and vortical flow development on pitching wings at high rates

    Science.gov (United States)

    Bernal, Luis; Yu, Huai-Te; Ol, Michael; Granlund, Kenneth

    2014-11-01

    Recent experimental results of pitching flat plate wings are presented. High pitch-rate perching maneuvers are frequently used by birds for feeding and landing. Insects use very fast rotation rates at the end of each flapping stroke, which results in high thrust and precise flight. These wing motions are also of interest for engineered micro air vehicles to achieve semi-autonomous landing by unskilled operators. The wing motion considered is a constant rotation rate pitch motion from 0 to 45 degrees of an aspect-ratio-4 flat-plate wing. The goal is to gain a better understanding of force generation mechanisms and their relationship to two- and three-dimensional vortical flow structures. Leading edge, trailing edge, and tip vortices form with large separated flow regions over the wing, however comparison with linear potential flow theory gives good agreement. The evolution of the leading edge vortex is delayed for pivot axes locations downstream of the leading edge. Large forces at the end of the motion slowly return to the steady state value over more than 30 convective times. The flow in the near wake shows a brief period of vortex shedding and strong three dimensional effects. Two different three-dimensional flow features are observed: A rapid development of three-dimensionality in the core of the leading and trailing edge vortices and a swirl motion in the near wake. However the impact of these three-dimensional flow features on force development is small.

  20. Evaluation of High-Pitch Ungated Pediatric Cardiovascular Computed Tomography for the Assessment of Cardiac Structures in Neonates.

    Science.gov (United States)

    Sriharan, Mona; Lazoura, Olga; Pavitt, Christopher W; Castellano, Isabel; Owens, Catherine M; Rubens, Michael B; Padley, Simon P G; Nicol, Edward D

    2016-05-01

    We evaluated a high-pitch, non-electrocardiogram-gated cardiac computed tomographic protocol, designed to image both cardiac and extracardiac structures, including coronary arteries, in a neonatal population (less than 1 year old) that was referred for congenital heart disease assessment and compared it with an optimized standard-pitch protocol in an equivalent cohort. Twenty-nine high-pitch scans were compared with 31 age-matched, sex-matched, and weight-matched standard-pitch, dosimetrically equivalent scans. The visualization and subjective quality of both cardiac and extracardiac structures were scored by consensus between 2 trained blinded observers. Image noise, signal-to-noise and contrast-to-noise ratios, and radiation doses were also compared. The high-pitch protocol better demonstrated the pulmonary veins (P=0.03) and all coronary segments (all Pneonates, a high-pitch protocol improves coronary artery and pulmonary vein delineation compared with the standard-pitch protocol, allowing a more comprehensive assessment of cardiovascular anatomy while obviating the need for either patient sedation or heart rate control.

  1. Adenosine stress high-pitch 128-slice dual-source myocardial computed tomography perfusion for imaging of reversible myocardial ischemia: comparison with magnetic resonance imaging.

    Science.gov (United States)

    Feuchtner, Gudrun; Goetti, Robert; Plass, André; Wieser, Monika; Scheffel, Hans; Wyss, Christophe; Stolzmann, Paul; Donati, Olivio; Schnabl, Johannes; Falk, Volkmar; Alkadhi, Hatem; Leschka, Sebastian; Cury, Ricardo C

    2011-09-01

    Coronary computed tomography angiography (CTA) enables accurate anatomic evaluation of coronary artery stenosis but lacks information about hemodynamic significance. The aim of this study was to evaluate 128-slice myocardial CT perfusion (CTP) imaging with adenosine stress using a high-pitch mode, in comparison with cardiac MRI (CMR). Thirty-nine patients with intermediate to high coronary risk profile underwent adenosine stress 128-slice dual source CTP (128×0.6 mm, 0.28 seconds). Among those, 30 patients (64 ± 10 years, 6% women) also underwent adenosine stress CMR (1.5T). The 2-step CTP protocol consisted of (1) adenosine stress-CTP using a high-pitch factor (3.4) ECG-synchronized spiral mode and (2) rest-CTP/coronary-CTA using either high-pitch (heart rate 63 bpm). Results were compared with CMR and with invasive angiography in 25 patients. The performance of stress-CTP for detection of myocardial perfusion defects compared with CMR was sensitivity, 96%; specificity, 88%; positive predictive value (PPV), 93%; negative predictive value (NPV), 94% (per vessel); and sensitivity, 78%; specificity, 87%; PPV, 83%; NPV, 84% (per segment). The accuracy of stress-CTP for imaging of reversible ischemia compared with CMR was sensitivity, 95%; specificity, 96%; PPV, 95%; and NPV, 96% (per vessel). In 25 patients who underwent invasive angiography, the accuracy of CTA for detection of stenosis >70% was (per segment): sensitivity, 96%; specificity, 88%; PPV, 67%; and NPV, 98.9%. The accuracy improved from 84% to 95% after adding stress CTP to CTA. Radiation exposure of the entire stress/rest CT protocol was only 2.5 mSv. Adenosine-induced stress 128-slice dual-source high-pitch myocardial CTP allows for simultaneously assessment of reversible myocardial ischemia and coronary stenosis, with good diagnostic accuracy as compared with CMR and invasive angiography, at a very low radiation exposure.

  2. A Highly Miniaturized, Wireless Inertial Measurement Unit for Characterizing the Dynamics of Pitched Baseballs and Softballs

    Directory of Open Access Journals (Sweden)

    Noel C. Perkins

    2012-08-01

    Full Text Available Baseball and softball pitch types are distinguished by the path and speed of the ball which, in turn, are determined by the angular velocity of the ball and the velocity of the ball center at the instant of release from the pitcher’s hand. While radar guns and video-based motion capture (mocap resolve ball speed, they provide little information about how the angular velocity of the ball and the velocity of the ball center develop and change during the throwing motion. Moreover, mocap requires measurements in a controlled lab environment and by a skilled technician. This study addresses these shortcomings by introducing a highly miniaturized, wireless inertial measurement unit (IMU that is embedded in both baseballs and softballs. The resulting “ball-embedded” sensor resolves ball dynamics right on the field of play. Experimental results from ten pitches, five thrown by one softball pitcher and five by one baseball pitcher, demonstrate that this sensor technology can deduce the magnitude and direction of the ball’s velocity at release to within 4.6% of measurements made using standard mocap. Moreover, the IMU directly measures the angular velocity of the ball, which further enables the analysis of different pitch types.

  3. Low-dose, prospective triggered high-pitch spiral coronary computed tomography angiography: comparison with retrospective spiral technique.

    NARCIS (Netherlands)

    Srichai, M.B.; Lim, R.P.; Donnino, R.; Mannelli, L.; Hiralal, R.; Avery, R.; Ho, C.; Babb, J.S.; Jacobs, J.E.

    2012-01-01

    RATIONALE AND OBJECTIVES: Cardiac computed tomographic angiography algorithms emphasize radiation reduction while maintaining diagnostic image quality (IQ). The aim of this study was to evaluate IQ and interreader variability using prospective electrocardiographically triggered high-pitch spiral

  4. Relativistic electron dynamics produced by azimuthally localized poloidal mode ULF waves: Boomerang-shaped pitch angle evolutions

    Science.gov (United States)

    Hao, Y. X.; Zong, Q.-G.; Zhou, X.-Z.; Rankin, R.; Chen, X. R.; Liu, Y.; Fu, S. Y.; Spence, H. E.; Blake, J. B.; Reeves, G. D.

    2017-08-01

    We present an analysis of "boomerang-shaped" pitch angle evolutions of outer radiation belt relativistic electrons observed by the Van Allen Probes after the passage of an interplanetary shock on 7 June 2014. The flux at different pitch angles is modulated by Pc5 waves, with equatorially mirroring electrons reaching the satellite first. For 90° pitch angle electrons, the phase change of the flux modulations across energy exceeds 180° and increasingly tilts with time. Using estimates of the arrival time of particles of different pitch angles at the spacecraft location, a scenario is investigated in which shock-induced ULF waves interact with electrons through the drift resonance mechanism in a localized region westward of the spacecraft. Numerical calculations on particle energy gain with the modified ULF wavefield reproduce the observed boomerang stripes and modulations in the electron energy spectrogram. The study of boomerang stripes and their relationship to drift resonance taking place at a location different from the observation point adds new understanding of the processes controlling the dynamics of the outer radiation belt.

  5. Coronary calcium screening with dual-source CT: reliability of ungated, high-pitch chest CT in comparison with dedicated calcium-scoring CT

    Energy Technology Data Exchange (ETDEWEB)

    Hutt, Antoine; Faivre, Jean-Baptiste; Remy, Jacques; Remy-Jardin, Martine [CHRU et Universite de Lille, Department of Thoracic Imaging, Hospital Calmette (EA 2694), Lille (France); Duhamel, Alain; Deken, Valerie [CHRU et Universite de Lille, Department of Biostatistics (EA 2694), Lille (France); Molinari, Francesco [Centre Hospitalier General de Tourcoing, Department of Radiology, Tourcoing (France)

    2016-06-15

    To investigate the reliability of ungated, high-pitch dual-source CT for coronary artery calcium (CAC) screening. One hundred and eighty-five smokers underwent a dual-source CT examination with acquisition of two sets of images during the same session: (a) ungated, high-pitch and high-temporal resolution acquisition over the entire thorax (i.e., chest CT); (b) prospectively ECG-triggered acquisition over the cardiac cavities (i.e., cardiac CT). Sensitivity and specificity of chest CT for detecting positive CAC scores were 96.4 % and 100 %, respectively. There was excellent inter-technique agreement for determining the quantitative CAC score (ICC = 0.986). The mean difference between the two techniques was 11.27, representing 1.81 % of the average of the two techniques. The inter-technique agreement for categorizing patients into the four ranks of severity was excellent (weighted kappa = 0.95; 95 % CI 0.93-0.98). The inter-technique differences for quantitative CAC scores did not correlate with BMI (r = 0.05, p = 0.575) or heart rate (r = -0.06, p = 0.95); 87.2 % of them were explained by differences at the level of the right coronary artery (RCA: 0.8718; LAD: 0.1008; LCx: 0.0139; LM: 0.0136). Ungated, high-pitch dual-source CT is a reliable imaging mode for CAC screening in the conditions of routine chest CT examinations. (orig.)

  6. The Low Pitch of High-Frequency Complex Tones Relies on Temporal Fine Structure Information

    DEFF Research Database (Denmark)

    Santurette, Sébastien; Dau, Torsten

    2010-01-01

    structure (TFS) cues has been a matter of debate. It is also controversial up to which frequency TFS information remains available, and to what extent envelope cues become dominant as frequency increases. Using a pitch-matching paradigm, this study investigated whether the pitch of transposed tones...... the envelope rate fenv), or whether (C) no salient pitch is evoked (random matches). Six musically-trained normal-hearing subjects matched the fundamental pitch of a broadband pulse train to that of transposed tones with carrier frequencies fc = [3, 4, 5, 6, 7] kHz and envelope rates fenv = [fc/11.5, fc/14...

  7. [Clinical application of high-pitch excretory phase images during dual-source CT urography with stellar photon detector].

    Science.gov (United States)

    Sun, Hao; Xue, Hua-dan; Jin, Zheng-yu; Wang, Xuan; Chen, Yu; He, Yong-lan; Zhang, Da-ming; Zhu, Liang; Wang, Yun; Qi, Bing; Xu, Kai; Wang, Ming

    2014-10-01

    To retrospectively evaluate the clinical feasibility of high-pitch excretory phase images during dual-source CT urography with Stellar photon detector. Totally 100 patients received dual-source CT high-pitch urinary excretory phase scanning with Stellar photon detector [80 kV, ref.92 mAs, CARE Dose 4D and CARE kV, pitch of 3.0, filter back projection reconstruction algorithm (FBP)] (group A). Another 100 patients received dual-source CT high-pitch urinary excretory phase scanning with common detector(100 kV, ref.140 mAs, CARE Dose 4D, pitch of 3.0, FBP) (group B). Quantitative measurement of CT value of urinary segments (Hounsfield units), image noise (Hounsfield units), and effective radiation dose (millisievert) were compared using independent-samples t test between two groups. Urinary system subjective opacification scores were compared using Mann-Whitney U test between two groups. There was no significant difference in subjective opacification score of intrarenal collecting system and ureters between two groups (all P>0.05). The group A images yielded significantly higher CT values of all urinary segments (all P0.05). The effective radiation dose of group A (1.1 mSv) was significantly lower than that of group B (3.79 mSv) (Pexcretory phase dual-source CT urography with Stellar photon detector is feasible, with acceptable image noise and lower radiation dose.

  8. Transient Thermal Tensile Behaviour of Novel Pitch-Based Ultra-High Modulus CFRP Tendons

    Directory of Open Access Journals (Sweden)

    Giovanni Pietro Terrasi

    2016-12-01

    Full Text Available A novel ultra-high modulus carbon fibre reinforced polymer (CFRP prestressing tendon made from coal tar pitch-based carbon fibres was characterized in terms of high temperature tensile strength (up to 570 °C with a series of transient thermal and steady state temperature tensile tests. Digital image correlation was used to capture the high temperature strain development during thermal and mechanical loading. Complementary thermogravimetric (TGA and dynamic mechanical thermal (DMTA experiments were performed on the tendons to elucidate their high temperature thermal and mechanical behaviour. The novel CFRP tendons investigated in the present study showed an ambient temperature design tensile strength of 1400 MPa. Their failure temperature at a sustained prestress level of 50% of the design tensile strength was 409 °C, which is higher than the failure temperature of most fibre reinforced polymer rebars used in civil engineering applications at similar utilisation levels. This high-temperature tensile strength shows that there is potential to use the novel high modulus CFRP tendons in CFRP pretensioned concrete elements for building applications that fulfill the fire resistance criteria typically applied within the construction industry.

  9. Research on controlling middle spatial frequency error of high gradient precise aspheric by pitch tool

    Science.gov (United States)

    Wang, Jia; Hou, Xi; Wan, Yongjian; Shi, Chunyan; Zhong, Xianyun

    2016-09-01

    Extreme optical fabrication projects known as EUV and X-ray optic systems, which are representative of today's advanced optical manufacturing technology level, have special requirements for the optical surface quality. In synchroton radiation (SR) beamlines, mirrors of high shape accuracy is always used in grazing incidence. In nanolithograph systems, middle spatial frequency errors always lead to small-angle scattering or flare that reduces the contrast of the image. The slope error is defined for a given horizontal length, the increase or decrease in form error at the end point relative to the starting point is measured. The quality of reflective optical elements can be described by their deviation from ideal shape at different spatial frequencies. Usually one distinguishes between the figure error, the low spatial error part ranging from aperture length to 1mm frequencies, and the mid-high spatial error part from 1mm to 1 μm and from1 μm to some 10 nm spatial frequencies, respectively. Firstly, this paper will disscuss the relationship between slope error and middle spatial frequency error, which both describe the optical surface error along with the form profile. Then, experimental researches will be conducted on a high gradient precise aspheric with pitch tool, which aim to restraining the middle spatial frequency error.

  10. VAMOS: a VAriable MOde high acceptance Spectrometer

    CERN Document Server

    Savajols, H

    1999-01-01

    The study of reactions induced by the future SPIRAL beams at GANIL requires new techniques: the low intensity of secondary beams implies the need of a very high efficiency detection system ; the study of nearly or completely unknown nuclei, over a wide range of masses and energies, needs a very efficient method for attributing a reaction product to a nucleus. The VAriable MOde high acceptance Spectrometer VAMOS is being designed and built especially for this purpose.

  11. Acoustic and Perceptual Measurement of Expressive Prosody in High-Functioning Autism: Increased Pitch Range and What it Means to Listeners

    Science.gov (United States)

    Nadig, Aparna; Shaw, Holly

    2012-01-01

    Are there consistent markers of atypical prosody in speakers with high functioning autism (HFA) compared to typically-developing speakers? We examined: (1) acoustic measurements of pitch range, mean pitch and speech rate in conversation, (2) perceptual ratings of conversation for these features and overall prosody, and (3) acoustic measurements of…

  12. High Source Levels and Small Active Space of High-Pitched Song in Bowhead Whales (Balaena mysticetus)

    DEFF Research Database (Denmark)

    Tervo, Outi M.; Christoffersen, Mads F.; Simon, Malene

    2012-01-01

    The low frequency, powerful vocalizations of blue and fin whales may potentially be detected by conspecifics across entire ocean basins. In contrast, humpback and bowhead whales produce equally loud, but more complex broadband vocalizations composed of higher frequencies that suffer from higher...... attenuation. Here we evaluate the active space of high-pitched song notes of bowhead whales (Balaena mysticetus) in Western Greenland using measurements of song source levels and ambient noise. Four independent GPS-synchronized hydrophones were deployed through holes in the ice to localize vocalizing bowhead...... whales, estimate source levels and measure ambient noise. The song had a mean apparent source level of 185 ± 2 dB rms re 1µPa and a high mean centroid frequency of 444 ± 48 Hz. Using measured ambient noise levels in the area and Arctic sound spreading models, the estimated active space of these song...

  13. Coarse mode aerosols in the High Arctic

    Science.gov (United States)

    Baibakov, K.; O'Neill, N. T.; Chaubey, J. P.; Saha, A.; Duck, T. J.; Eloranta, E. W.

    2014-12-01

    Fine mode (submicron) aerosols in the Arctic have received a fair amount of scientific attention in terms of smoke intrusions during the polar summer and Arctic haze pollution during the polar winter. Relatively little is known about coarse mode (supermicron) aerosols, notably dust, volcanic ash and sea salt. Asian dust is a regular springtime event whose optical and radiative forcing effects have been fairly well documented at the lower latitudes over North America but rarely reported for the Arctic. Volcanic ash, whose socio-economic importance has grown dramatically since the fear of its effects on aircraft engines resulted in the virtual shutdown of European civil aviation in the spring of 2010 has rarely been reported in the Arctic in spite of the likely probability that ash from Iceland and the Aleutian Islands makes its way into the Arctic and possibly the high Arctic. Little is known about Arctic sea salt aerosols and we are not aware of any literature on the optical measurement of these aerosols. In this work we present preliminary results of the combined sunphotometry-lidar analysis at two High Arctic stations in North America: PEARL (80°N, 86°W) for 2007-2011 and Barrow (71°N,156°W) for 2011-2014. The multi-years datasets were analyzed to single out potential coarse mode incursions and study their optical characteristics. In particular, CIMEL sunphotometers provided coarse mode optical depths as well as information on particle size and refractive index. Lidar measurements from High Spectral Resolution lidars (AHSRL at PEARL and NSHSRL at Barrow) yielded vertically resolved aerosol profiles and gave an indication of particle shape and size from the depolarization ratio and color ratio profiles. Additionally, we employed supplementary analyses of HYSPLIT backtrajectories, OMI aerosol index, and NAAPS (Navy Aerosol Analysis and Prediction System) outputs to study the spatial context of given events.

  14. Ultra-low dose dual-source high-pitch computed tomography of the paranasal sinus: diagnostic sensitivity and radiation dose

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, Boris; Zangos, Stefan; Friedrichs, Ingke; Bauer, Ralf W.; Kerl, Matthias; Vogl, Thomas J.; Martin M Mack, Martin M. (Clinic of the Goethe Univ., Dept. of Diagnostic and Interventional Radiology, Frankfurt (Germany)), email: boris.schell@googlemail.com; Potente, Stefan (Clinic of the Goethe Univ., Dept. of Forensic Medicine, Frankfurt (Germany))

    2012-05-15

    Background: Today's gold standard for diagnostic imaging of inflammatory diseases of the paranasal sinus is computed tomography (CT). Purpose: To evaluate diagnostic sensitivity and radiation dose of an ultra-low dose dual-source CT technique. Material and Methods: Paranasal sinuses of 14 cadaveric heads were independently evaluated by two readers using a modern dual-source CT with lowest reasonable dosage in high-pitch mode (100 kV, 10 mAs, collimation 0.6 mm, pitch value 3.0). Additionally the head part of an anthropomorphic Alderson-Rando phantom was equipped with thermoluminescent detectors to measure radiation exposure to the eye lenses and thyroid gland. Results: Diagnostic accuracy regarding sinusoidal fluid, nasal septum deviation, and mucosal swelling was 100%. Mastoid fluid was detected in 76% and 92%, respectively. In the phantom study, average measured eye lens dosage was 0.64 mGy; radiation exposure of the thyroid gland was 0.085 mGy. Conclusion: Regarding evaluation of inflammatory diseases of the paranasal sinus this study indicates sufficient accuracy of the proposed CT protocol at a very low dosage level

  15. Thermally induced nonlinear mode coupling in high power fiber amplifiers

    DEFF Research Database (Denmark)

    Johansen, Mette Marie; Hansen, Kristian Rymann; Alkeskjold, Thomas T.

    2013-01-01

    Thermally induced nonlinear mode coupling leads to transverse mode instability (TMI) in high power fiber amplifiers. A numerical model including altering mode profiles from thermal effects and waveguide perturbations predicts a TMI threshold of ~200W.......Thermally induced nonlinear mode coupling leads to transverse mode instability (TMI) in high power fiber amplifiers. A numerical model including altering mode profiles from thermal effects and waveguide perturbations predicts a TMI threshold of ~200W....

  16. Effect of performance time of the high-pitched blowing vocal exercise in the voice of women.

    Science.gov (United States)

    Moreira, Fabíola Santos; Gama, Ana Cristina Côrtes

    2017-02-16

    To analyze the results of the runtimes of one, three, five, and seven minutes of the high-pitched blowing vocal exercise in women without voice complaints and with dysphonia and vocal nodules. This is an experimental study with a consecutive and convenience sample of 60 women divided into two groups: 30 participants with dysphonia caused by vocal fold nodules (study group - SG) and 30 participants without vocal complaints (control group - CG). All participants performed the high-pitched blowing vocal exercise for one, three, five, and seven minutes. Sustained vowels /a/ and counting from one to ten were recorded before and after each exercise runtime. The recordings were randomized and evaluated by comparison task by four speech-language pathologists using the parameters grade of vocal deviation, roughness, breathiness, asthenia, strain and instability (GRBASI). The acoustic parameters analyzed were fundamental frequency, jitter, shimmer, period perturbation quotient, amplitude perturbation quotient, and harmonics-to-noise ratio. After each vocal exercise runtime, the participants responded whether they had felt vocal discomfort using a visual analogue scale. Auditory-perceptual analysis in the SG showed improved overall severity of dysphonia and breathiness after three minutes and worsening of these acoustic parameters after seven minutes of exercise performance. Participants in the SG reported self-perception of vocal discomfort after seven minutes of exercise performance. The ideal prescription time for the high-pitched blowing vocal exercise in dysphonic women is three minutes; worsening of voice quality and perception of vocal discomfort occurs after seven minutes.

  17. The Identification of High-pitched Sung Vowels in Sense and Nonsense Words by Professional Singers and Untrained Listeners.

    Science.gov (United States)

    Deme, Andrea

    2017-03-01

    High-pitched sung vowels may be considered phonetically "underspecified" because of (i) the tuning of the F 1 to the f 0 accompanying pitch raising and (ii) the wide harmonic spacing of the voice source resulting in the undersampling of the vocal tract transfer function. Therefore, sung vowel intelligibility is expected to decrease as the f 0 increases. Based on the literature of speech perception, it is often suggested that sung vowels are better perceived if uttered in consonantal (CVC) context than in isolation even at high f 0 . The results for singing, however, are contradictory. In the present study, we further investigate this question. We compare vowel identification in sense and nonsense CVC sequences and show that the positive effect of the context disappears if the number of legal choices in a perception test is similar in both conditions, meaning that any positive effect of the CVC context may only stem from the smaller number of possible responses, i.e., from higher probabilities. Additionally, it is also tested whether the training in production (i.e., singing training) may also lead to a perceptual advantage of the singers over nonsingers in the identification of high-pitched sung vowels. The results show no advantage of this kind. Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

  18. A new design of a directional coupler for high order mode multiplexing in few mode fibers

    Science.gov (United States)

    Trichili, Abderrahmen; Ben Salem, Amine; Cherif, Rim; Zghal, Mourad; Forbes, Andrew

    2014-05-01

    We propose a new and versatile design of a directional coupler able to generate and multiplex high order modes in few mode fibers. The designed device can selectively generate five high order modes and multiplex them in a few mode fiber with an overall insertion loss not exceeding 3dB at the telecommunication wavelength λ = 1550 nm. The mode dependent loss is found to be weakly dependent to the wavelength. The proposed device is very promising for high order mode multiplexing and suitable for high bit-rate optical communication systems.

  19. Roll-pitch-yaw autopilot design for nonlinear time-varying missile using partial state observer based global fast terminal sliding mode control

    Directory of Open Access Journals (Sweden)

    Awad Ahmed

    2016-10-01

    Full Text Available The acceleration autopilot design for skid-to-turn (STT missile faces a great challenge owing to coupling effect among planes, variation of missile velocity and its parameters, inexistence of a complete state vector, and nonlinear aerodynamics. Moreover, the autopilot should be designed for the entire flight envelope where fast variations exist. In this paper, a design of integrated roll-pitch-yaw autopilot based on global fast terminal sliding mode control (GFTSMC with a partial state nonlinear observer (PSNLO for STT nonlinear time-varying missile model, is employed to address these issues. GFTSMC with a novel sliding surface is proposed to nullify the integral error and the singularity problem without application of the sign function. The proposed autopilot consisting of two-loop structure, controls STT maneuver and stabilizes the rolling with a PSNLO in order to estimate the immeasurable states as an output while its inputs are missile measurable states and control signals. The missile model considers the velocity variation, gravity effect and parameters’ variation. Furthermore, the environmental conditions’ dynamics are modeled. PSNLO stability and the closed loop system stability are studied. Finally, numerical simulation is established to evaluate the proposed autopilot performance and to compare it with existing approaches in the literature.

  20. Low-dose high-pitch CT angiography of the supraaortic arteries using sinogram-affirmed iterative reconstruction.

    Directory of Open Access Journals (Sweden)

    Dietrich Beitzke

    Full Text Available OBJECTIVE: To prospectively evaluate image quality and radiation dose using a low-dose computed tomography angiography protocol and iterative image reconstruction for high-pitch dual-source CT-angiography (DSCTA of the supraaortic arteries. MATERIAL AND METHODS: DSCTA was performed in 42 patients, using either 120 kVp tube voltage, 120 mAS tube current, 2.4 pitch and filtered back projection, or 100 kVp tube voltage, 100 mAs tube current, 3.2 pitch, and sinogram affirmed iterative reconstruction. Measurements of vessel attenuation, of the contrast-to-noise ratio (CNR and the signal-to-noise ratio (SNR were performed to objectively evaluate image quality. Two readers evaluated subjective image quality and image noise, using a four-point scale. Effective dose was used to compare the differences in radiation dose. RESULTS: Low-dose protocol application showed significantly higher vessel opacification (p = 0.013, and non-significantly higher CNR and SNR values. There was no difference in the subjective image quality and image noise reading between the protocols. Effective dose was significantly lower using the low-dose protocol (1.29 ± 0.21 mSv vs. 2.92 ± 0.72 mSv; p < 0.001. CONCLUSION: The combined use of reduced tube voltage, reduced tube current, and iterative reconstruction reduces radiation dose by 55.4% in high-pitch DSCTA of the supraaortic arteries without impairment of image quality.

  1. Suppression of high order modes employing active self-imaging mode filter in large mode area strongly pumped fiber amplifier

    Science.gov (United States)

    Zhao, Xiang; Bai, Gang; Zheng, Ye; Chen, Xiaolong; Yang, Yifeng; Qi, Yunfeng; He, Bing; Zhou, Jun

    2017-10-01

    To suppress high order modes and improve the beam quality, an active self-imaging mode filter based on multimode interference and self-imaging effect is proposed in large mode area (LMA) fiber amplifier. With this filter structure, transverse mode competition and individual transverse mode power distributions in strongly pumped fiber amplifiers are theoretically demonstrated. Employing this mode selection technique in 30/400 LMA strongly pumped fiber amplifier, the percentage of the fundamental mode rises from 27.8% (without filter) to 96.3%. By the modal power decomposition, the M2 parameter of beam quality decrease dramatically from 2.24 to 1.11 (0 relative phase) and from 3.01 to 1.24 (π/2 relative phase). This study provides a new method to achieve single mode in LMA fiber amplifier and this filter would be extended to larger mode area fiber amplifier to improve the beam quality.

  2. Extending wind turbine operational conditions; a comparison of set point adaptation and LQG individual pitch control for highly turbulent wind

    Science.gov (United States)

    Engels, W. P.; Subhani, S.; Zafar, H.; Savenije, F.

    2014-06-01

    Extreme wind conditions can cause excessive loading on the turbine. This not only results in higher design loads, but when these conditions occur in practice, will also result in higher maintenance cost. Although there are already effective methods of dealing with gusts, other extreme conditions should also be examined. More specifically, extreme turbulence conditions (e.g. those specified by design load case 1.3 in IEC61400-1 ed. 3) require special attention as they can lead to design-driving extreme loads on blades, tower and other wind turbine components. This paper examines two methods to deal with extreme loads in a case of extreme turbulent wind. One method is derating the turbine, the other method is an individual pitch control (IPC) algorithm. Derating of the turbine can be achieved in two ways, one is changing the rated torque, the other is changing the rated rotor speed. The effect of these methods on fatigue loads and extreme loads is examined. Non-linear aero-elastic simulations using Phatas, show that reducing the rated rotor speed is far more effective at reducing the loads than reducing torque. Then, the IPC algorithm is proposed. This algorithm is a linear quadratic Gaussian (LQG) controller based on a time invariant model, defined in the fixed reference frame that includes the first tower and blade modes. Because this method takes the dynamics of the system into account more than conventional IPC control, it is expected that these loads dealt with more effectively, when they are particularly relevant. It is expected that in extreme turbulent the blade and tower dynamics are indeed more relevant. The effect of this algorithm on fatigue loads and pitch effort is examined and compared with the fatigue loads and pitch effort of reference IPC. Finally, the methods are compared in non-linear aero-elastic simulations with extreme turbulent wind.

  3. Embedded pitch adapters: A high-yield interconnection solution for strip sensors

    Energy Technology Data Exchange (ETDEWEB)

    Ullán, M., E-mail: miguel.ullan@imb-cnm.csic.es [Centro Nacional de Microelectronica (IMB-CNM, CSIC), Campus UAB-Bellaterra, 08193 Barcelona (Spain); Allport, P.P.; Baca, M.; Broughton, J.; Chisholm, A.; Nikolopoulos, K.; Pyatt, S.; Thomas, J.P.; Wilson, J.A. [School of Physics and Astronomy, University of Birmingham, Birmingham B15 2TT (United Kingdom); Kierstead, J.; Kuczewski, P.; Lynn, D. [Brookhaven National Laboratory, Physics Department and Instrumentation Division, Upton, NY 11973-5000 (United States); Hommels, L.B.A. [Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Fleta, C.; Fernandez-Tejero, J.; Quirion, D. [Centro Nacional de Microelectronica (IMB-CNM, CSIC), Campus UAB-Bellaterra, 08193 Barcelona (Spain); Bloch, I.; Díez, S.; Gregor, I.M.; Lohwasser, K. [DESY, Notkestrasse 85, 22607 Hamburg (Germany); and others

    2016-09-21

    A proposal to fabricate large area strip sensors with integrated, or embedded, pitch adapters is presented for the End-cap part of the Inner Tracker in the ATLAS experiment. To implement the embedded pitch adapters, a second metal layer is used in the sensor fabrication, for signal routing to the ASICs. Sensors with different embedded pitch adapters have been fabricated in order to optimize the design and technology. Inter-strip capacitance, noise, pick-up, cross-talk, signal efficiency, and fabrication yield have been taken into account in their design and fabrication. Inter-strip capacitance tests taking into account all channel neighbors reveal the important differences between the various designs considered. These tests have been correlated with noise figures obtained in full assembled modules, showing that the tests performed on the bare sensors are a valid tool to estimate the final noise in the full module. The full modules have been subjected to test beam experiments in order to evaluate the incidence of cross-talk, pick-up, and signal loss. The detailed analysis shows no indication of cross-talk or pick-up as no additional hits can be observed in any channel not being hit by the beam above 170 mV threshold, and the signal in those channels is always below 1% of the signal recorded in the channel being hit, above 100 mV threshold. First results on irradiated mini-sensors with embedded pitch adapters do not show any change in the interstrip capacitance measurements with only the first neighbors connected.

  4. Pitch Estimation, Voicing Decision, and Noise Spectrum Estimation for Speech Corrupted by High Levels of Additive Noise.

    Science.gov (United States)

    Krubsack, David Allan

    1990-01-01

    This dissertation presents two algorithms that extract parameters which are important to speech processing in high levels of noise. The first algorithm determines whether a signal containing noise corrupted human speech is voiced or not and estimates the fundamental frequency (pitch) of voiced speech. The second algorithm produces an estimate of the additive noise which is corrupting the speech. Previous research related to the voicing decision and pitch estimation has been concentrated at signal-to -noise ratios (SNRs) above 0 dB. Consequently, speech processing requiring the extraction of these parameters in higher levels of noise could not be performed with much success. The research presented in this dissertation concentrates on SNRs around and below 0 dB. Although the algorithm, based on the autocorrelation function, is designed to work well for high levels of noise, good results for the no noise case have been maintained. The idea of a confidence measure for parameter estimation is introduced. Confidence measures are defined and developed for both the voicing decision and the pitch estimation algorithms. Estimation of noise that is corrupting a speech signal has been motivated by the need to enhance the corrupted speech. Previous research has concentrated on speech which is band limited to about 3500 Hz. Therefore, the estimation of the noise corrupting high frequency speech had not been considered. The noise estimation algorithm presented in this dissertation considers the effects of high frequency speech on the noise estimate in addition to the effects of low frequency speech. A new spectral averaging method is introduced which significantly reduces the corrupting effect of the speech components on the noise estimate for SNRs above 0 dB. The algorithm is tested for stationary white noise, stationary non-white noise, and non-stationary white noise.

  5. Structural and High-Temperature Tensile Properties of Special Pitch-Coke Graphites

    Science.gov (United States)

    Kotlensky, W. V.; Martens, H. E.

    1961-01-01

    The room-temperature structural properties and the tensile properties up to 5000 F (275O C) were determined for ten grades of specially prepared petroleum-coke coal-tar-pitch graphites which were graphitized at 5430 F (3000 C). One impregnation with coal-tar pitch increased the bulk density from 1.41 to 1.57 g/cm3 and the maximum strength at 4500 F (2500 C) from 4000 to 5700 psi. None of the processing parameters studied had a marked effect on the closed porosity or the X-ray structure or the per cent graphitization. The coarse-particle filler resulted in the lowest coefficient of thermal expansion and the fine-particle filler in the highest coefficient. A marked improvement in uniformity of tensile strength was observed. A standard-deviation analysis gave a one-sigma value of approximately 150 psi for one of these special grades and values of 340-420 psi for three commercial grades.

  6. High efficiency mode-locked, cylindrical vector beam fiber laser based on a mode selective coupler.

    Science.gov (United States)

    Wan, Hongdan; Wang, Jie; Zhang, Zuxing; Cai, Yu; Sun, Bin; Zhang, Lin

    2017-05-15

    We propose and demonstrate an all-fiber passively mode-locked laser with a figure-8 cavity, which generates pulsed cylindrical vector beam output based on a mode selective coupler (MSC). The MSC made of a two mode fiber and a standard single mode fiber is used as both the intracavity transverse mode converter and mode splitter with a low insertion loss of about 0.65 dB. The slope efficiency of the fiber laser is > 3%. Through adjusting the polarization state in the laser cavity, both radially and azimuthally polarized beams have been obtained with high mode purity which are measured to be > 94%. The laser operates at 1556.3 nm with a spectral bandwidth of 3.2 nm. The mode-locked pulses have duration of 17 ns and a repetition rate of 0.66 MHz.

  7. High peak-power fiber laser based on a non filamented-core fully-aperiodic large pitch fiber

    Science.gov (United States)

    Benoit, A.; Malleville, M. A.; Du Jeu, R.; Dauliat, R.; Darwich, D.; Jamier, R.; Grimm, S.; Kobelke, Jens; Schuster, K.; Roy, P.

    2017-02-01

    In this communication, the authors report on the first high peak-power emission obtained using a solid non-filamented core fully-aperiodic large pitch fiber manufactured by the REPUSIL method which is based on the sintering and vitrification of micrometric doped silica powders. Using a simple amplifier stage based on a 75 cm long piece of a fullyaperiodic large pitch fiber with a fiber core of 50 μm, an average output power of 95 W was achieved with an available pump power of 175 W, corresponding to an optical-to-optical efficiency of 54 %. The peak power reaches about 35 kW for pulse duration of 200 ps at a repetition rate of 13.5 MHz. A recent evolution of our set-up using a seeder delivering an average power of 4 W at 1 MHz with a pulse duration of 50 ps led to the emission of 71.4W in average power corresponding to a peak power of 1.42 MW. These results present the first demonstration of high average and high peak power in pulsed regime for these fibers.

  8. High pitch, low voltage dual source CT pulmonary angiography: assessment of image quality and diagnostic acceptability with hybrid iterative reconstruction.

    Science.gov (United States)

    McLaughlin, Patrick D; Liang, T; Homiedan, M; Louis, L J; O'Connell, T W; Krzymyk, Karl; Nicolaou, S; Mayo, J R

    2015-04-01

    Increased use of CT Pulmonary angiography in suspected pulmonary embolism (PE) has driven research to minimize radiation dose while maintaining image quality and diagnostic accuracy. Following institutional review board approval, we performed a retrospective comparison study in patients with suspected PE. Patients were scanned using an ultra high pitch dual source technique (pitch = 2.6) using 120 kV (SVCTPA) (n = 54) or 100 kV (RV-CTPA) (n = 52). SV-CTPA images were reconstructed using filtered back projection (SV-wFBP) and RV-CTPA images were reconstructed using both FBP (RV-wFBP) and Iterative Reconstruction (RV-IR). Comparison of radiation dose, diagnostic ability, subjective image noise, quality, and sharpness, diagnostic agreement, signal to noise (SNR) and contrast to noise ratios (CNR) were performed. Mean effective dose was 2.56 ± 0.19 mSv for the RV protocol compared to 5.36 ± 0.60 mSv for the SV. The RV-CTPA protocol resulted in a mean DLP reduction of 52 % and mean CTDI reduction of 51 %. Pulmonary artery SNR and CNR were significantly higher on RV-IR images than SV-wFBP (p = 0.007, p = 0.003). Mean subjective image noise, quality and sharpness scores did not differ significantly between the SV-wFBP and RVIR images (p > 0.05). Subjective quality scores were significantly better for the RV-IR group compared to the RV-wFBP group (p perfect (κ = 0.891, p pitch dual source CTPA examinations acquired using a reduced voltage resulting in higher mean pulmonary artery SNR and CNR when compared to both RV-wFBP and SV-CTPA.

  9. Pitch Fork

    DEFF Research Database (Denmark)

    Williams, Peter Leslie; Overholt, Daniel

    2017-01-01

    Pitch Fork is a prototype of an alternate, actuated digital musical instrument (DMI). It uses 5 infra-red and 4 piezoelectric sensors to control an additive synthesis engine. Iron bars are used as the physical point of contact in interaction with the aim of using this materials natural acoustic p...... properties as a control signal for aspects of the digitally produced sound. This choice of material was also chosen to affect player experience. Sensor readings are relayed to a Macbook via an Arduino Mega. Mappings and audio output signal is carried out with Pure Data Extended....

  10. Study of current-mode active pixel sensor circuits using amorphous InSnZnO thin-film transistor for 50-μm pixel-pitch indirect X-ray imagers

    Science.gov (United States)

    Cheng, Mao-Hsun; Zhao, Chumin; Kanicki, Jerzy

    2017-05-01

    Current-mode active pixel sensor (C-APS) circuits based on amorphous indium-tin-zinc-oxide thin-film transistors (a-ITZO TFTs) are proposed for indirect X-ray imagers. The proposed C-APS circuits include a combination of a hydrogenated amorphous silicon (a-Si:H) p+-i-n+ photodiode (PD) and a-ITZO TFTs. Source-output (SO) and drain-output (DO) C-APS are investigated and compared. Acceptable signal linearity and high gains are realized for SO C-APS. APS circuit characteristics including voltage gain, charge gain, signal linearity, charge-to-current conversion gain, electron-to-voltage conversion gain are evaluated. The impact of the a-ITZO TFT threshold voltage shifts on C-APS is also considered. A layout for a pixel pitch of 50 μm and an associated fabrication process are suggested. Data line loadings for 4k-resolution X-ray imagers are computed and their impact on circuit performances is taken into consideration. Noise analysis is performed, showing a total input-referred noise of 239 e-.

  11. Experimental study of the mode instability onset threshold in high-power FA-LPF lasers.

    Science.gov (United States)

    Malleville, Marie-Alicia; Dauliat, Romain; Benoît, Aurélien; Leconte, Baptiste; Darwich, Dia; Jeu, Rémi du; Jamier, Raphaël; Schuster, Kay; Roy, Philippe

    2017-12-15

    We report here on an experimental investigation of the temporal behavior of transverse mode instabilities into "fully aperiodic large-pitch fibers" (FA-LPFs) operated in high-power continuous-wave laser configuration. To ensure an effective transverse single-mode emission into FA-LPFs, a perfect index matching between the active core and the background cladding materials (Δn=0) is required. The original design of such fibers enables an effective transverse single-mode emission by strengthening the higher-order mode delocalization out of the gain region, even for high heat load levels, consequently leading to the improvement of the beam spatial quality. The study was conducted over fibers of various gain region diameters, from 58 to 100 μm, for a refractive index mismatch Δn of about +8×10-5. The emitted beam is characterized using both M2 measurements and time traces to study the changeover of a stable temporal behavior to an unstable one.

  12. High-order mode based dispersion compensating modules using spatial mode conversion

    Science.gov (United States)

    Tur, M.; Menashe, D.; Japha, Y.; Danziger, Y.

    High-Order Mode Dispersion Compensating Modules (HOM-DCM) using spatial optical transformations for mode conversion are reviewed. It is shown that mode transformers using this technology can be designed to transform the LP01 mode of SMF fibers to the LP02 mode of specially designed dispersion compensating High-Order Mode Fiber (HOMF), with typical insertion loss of ~1 dB, and typical extinction ratio to other modes less than -20 dB.TheHOMFitself can provide high negative dispersion [typically in the range of 400-600 ps/(nm km)], and high negative dispersion slope, allowing efficient compensation of all types of transmission fiber. Combining two mode transformers with HOMF and possibly trim fiber for fine-tuning, results, for example, in a HOM-DCM that compensates 100 km LEAF R ® fiber, with Insertion loss mode transformers and fiber coupling within the HOMF. MPI values of < -36 dB have been shown to allow error free transmission of 10 Gb/s signals over up to 6000 km. Finally, a number of applications well suited to the properties of HOM-DCMs are reviewed.

  13. Broadband high-order mode pass filter based on mode conversion.

    Science.gov (United States)

    Ahmmed, Kazi Tanvir; Chan, Hau Ping; Li, Binghui

    2017-09-15

    We report a unique concept to implement a high-order mode pass filter using mode converters. Our proposed design method implements a high-order mode pass filter of any order, uses different mode converters available, and applies to a variety of planar lightwave circuit material platforms. We fabricate a broadband fundamental mode filter device using a Mach-Zehnder interferometer and Y-junctions to demonstrate our idea. The performance of the fabricated device is demonstrated experimentally in the wavelength range of 1.530-1.565 μm (C-band). This filter exhibits a simulated extinction ratio of 37 dB with an excess loss of 0.52 dB for the first-order mode transmission.

  14. Small Pitch Transition-Edge Sensors with Broadband High Spectral Resolution for Solar Physics

    Science.gov (United States)

    Smith, S. J.; Adams, J. S.; Eckart, M. E.; Smith, Adams; Bailey, C. N.; Bandler, S. R.; Chevenak, J. A.; Finkbeiner, F. M.; Kelley, R. L.; Kilbourne, C. A.; hide

    2012-01-01

    We are developing small pitch transition-edge sensor (TES) X-ray detectors optimized for solar astronomy. These devices are fabricated on thick Si substrates with embedded Cu heat-sink layer. We use 35 x 35 square micrometers Mo/Au TESs with 4.5 micrometer thick Au absorbers. We have tested devices with different geometric absorber stem contact areas with the TES and surrounding substrate area. This allows us to investigate the loss of athermal phonons to the substrate. Results show a correlation between thc stem contact area and a broadening in the spectral line shape indicative of athermal phonon loss. When the contact area is minimized we have obtained exceptional broadband spectral resolution of 1.28 plus or minus 0.03 eV at an energy of 1.5 keV, 1.58 plus or minus 0.07 eV at 5.9 keV and 1.96 plus or minus 0.08 eV at 8 keV. The linearity in the measured gain scale is understood in the context of the longitudinal proximity effect from the electrical bias leads resulting in transition characteristics that are strongly dependent upon TES size.

  15. Development of simultaneous pitch encoding: infants show a high voice superiority effect.

    Science.gov (United States)

    Marie, Céline; Trainor, Laurel J

    2013-03-01

    Infants must learn to make sense of real-world auditory environments containing simultaneous and overlapping sounds. In adults, event-related potential studies have demonstrated the existence of separate preattentive memory traces for concurrent note sequences and revealed perceptual dominance for encoding of the voice with higher fundamental frequency of 2 simultaneous tones or melodies. Here, we presented 2 simultaneous streams of notes (15 semitones apart) to 7-month-old infants. On 50% of trials, either the higher or the lower note was modified by one semitone, up or down, leaving 50% standard trials. Infants showed mismatch negativity (MMN) to changes in both voices, indicating separate memory traces for each voice. Furthermore, MMN was earlier and larger for the higher voice as in adults. When in the context of a second voice, representation of the lower voice was decreased and that of the higher voice increased compared with when each voice was presented alone. Additionally, correlations between MMN amplitude and amount of weekly music listening suggest that experience affects the development of auditory memory. In sum, the ability to process simultaneous pitches and the dominance of the highest voice emerge early during infancy and are likely important for the perceptual organization of sound in realistic environments.

  16. Ethnicity effects in relative pitch.

    Science.gov (United States)

    Hove, Michael J; Sutherland, Mary Elizabeth; Krumhansl, Carol L

    2010-06-01

    Absolute pitch (AP), the rare ability to identify a musical pitch, occurs at a higher rate among East Asian musicians. This has stimulated considerable research on the comparative contributions of genetic and environmental factors. Two studies examined whether a similar ethnicity effect is found for relative pitch (RP), identifying the distance or interval between two tones. Nonmusicians (n = 103) were trained to label musical intervals and were subsequently tested on interval identification. We establish similar ethnicity effects: Chinese and Korean participants consistently outperformed other participants in RP tasks, but not in a "relative rhythm" control task. This effect is not driven by previous musical or tone-language experience. The parallel with the East Asian advantage for AP suggests that enhanced perceptual-cognitive processing of pitch is more general and is not limited to highly trained musicians. This effect opens up many research questions concerning the environmental and genetic contributions related to this more general pitch-based ability.

  17. Image Quality of Coronary Arteries on Non-electrocardiography-gated High-Pitch Dual-Source Computed Tomography in Children with Congenital Heart Disease.

    Science.gov (United States)

    Kanie, Yuichiro; Sato, Shuhei; Tada, Akihiro; Kanazawa, Susumu

    2017-10-01

    This study aimed to evaluate image quality of coronary artery imaging on non-electrocardiography (ECG)-gated high-pitch dual-source computed tomography (DSCT) in children with congenital heart disease (CHD) and to assess factors affecting image quality. We retrospectively reviewed the records of 142 children with CHD who underwent non-ECG-gated high-pitch DSCT. The subjective image quality of the proximal coronary segments was graded using a five-point scale. A score coronary segments in children with CHD. Lower body weight was a factor that led to poorer image quality of the coronary arteries.

  18. Simulation study of high-frequency energetic particle driven geodesic acoustic mode

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hao, E-mail: wanghao@nifs.ac.jp; Ido, Takeshi; Osakabe, Masaki [National Institute for Fusion Science, Toki 509-5292 (Japan); Todo, Yasushi [National Institute for Fusion Science, Toki 509-5292 (Japan); The Graduate University for Advanced Studies, Toki 509-5292 (Japan)

    2015-09-15

    High-frequency energetic particle driven geodesic acoustic modes (EGAM) observed in the large helical device plasmas are investigated using a hybrid simulation code for energetic particles and magnetohydrodynamics (MHD). Energetic particle inertia is incorporated in the MHD momentum equation for the simulation where the beam ion density is comparable to the bulk plasma density. Bump-on-tail type beam ion velocity distribution created by slowing down and charge exchange is considered. It is demonstrated that EGAMs have frequencies higher than the geodesic acoustic modes and the dependence on bulk plasma temperature is weak if (1) energetic particle density is comparable to the bulk plasma density and (2) charge exchange time (τ{sub cx}) is sufficiently shorter than the slowing down time (τ{sub s}) to create a bump-on-tail type distribution. The frequency of high-frequency EGAM rises as the energetic particle pressure increases under the condition of high energetic particle pressure. The frequency also increases as the energetic particle pitch angle distribution shifts to higher transit frequency. It is found that there are two kinds of particles resonant with EGAM: (1) trapped particles and (2) passing particles with transit frequency close to the mode frequency. The EGAMs investigated in this work are destabilized primarily by the passing particles whose transit frequencies are close to the EGAM frequency.

  19. Chemical characterization of pitch deposits produced in the manufacturing of high-quality paper pulps from hemp fibers.

    Science.gov (United States)

    Gutiérrez, Ana; del Río, José C

    2005-09-01

    The composition of pitch deposits occurring in pulp sheets and mill circuits during soda/anthraquinone pulping and elemental chlorine-free pulp bleaching of bast fibers of industrial hemp (Cannabis sativa) was studied. Pitch deposits were extracted with acetone, and the extracts analyzed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). Acetone extracts (15-25% of pitch deposits) were constituted by the defoamers used at the mill and by lipophilic extractives from hemp fibers. Acetone-insoluble residues (75-85% of pitch deposits) were analyzed by pyrolysis-GC/MS in the presence and absence of tetramethylammonium hydroxide. These residues were constituted by salts of fatty acids (arising from hemp fibers) with calcium, magnesium, aluminum and other cations that were identified in the deposits. It was concluded that inappropriate use of defoamer together with the presence of multivalent ions seemed to be among the causes of hemp extractives deposition in the pitch problems reported here.

  20. Stable switching among high-order modes in polariton condensates

    Science.gov (United States)

    Sun, Yongbao; Yoon, Yoseob; Khan, Saeed; Ge, Li; Steger, Mark; Pfeiffer, Loren N.; West, Ken; Türeci, Hakan E.; Snoke, David W.; Nelson, Keith A.

    2018-01-01

    We report multistate optical switching among high-order bouncing-ball modes ("ripples") and whispering-gallery modes ("petals") of exciton-polariton condensates in a laser-generated annular trap. By tailoring the diameter and power of the annular trap, the polariton condensate can be switched among different trapped modes, accompanied by redistribution of spatial densities and superlinear increase in the emission intensities, implying that polariton condensates in this geometry could be exploited for an all-optical multistate switch. A model based on non-Hermitian modes of the generalized Gross-Pitaevskii equation reveals that this mode switching arises from competition between pump-induced gain and in-plane polariton loss. The parameters for reproducible switching among trapped modes have been measured experimentally, giving us a phase diagram for mode switching. Taken together, the experimental result and theoretical modeling advance our fundamental understanding of the spontaneous emergence of coherence and move us toward its practical exploitation.

  1. Dynamic motion modes of high temperature superconducting maglev on a 45-m long ring test line

    Science.gov (United States)

    Lei, W. Y.; Qian, N.; Zheng, J.; Jin, L. W.; Zhang, Y.; Deng, Z. G.

    2017-10-01

    With the development of high temperature superconducting (HTS) maglev, studies on the running stability have become more and more significant to ensure the operation safety. An experimental HTS maglev vehicle was tested on a 45-m long ring test line under the speed from 4 km/h to 20 km/h. The lateral and vertical acceleration signals of each cryostat were collected by tri-axis accelerometers in real time. By analyzing the phase relationship of acceleration signals on the four cryostats, several typical motion modes of the HTS maglev vehicle, including lateral, yaw, pitch and heave motions were observed. This experimental finding is important for the next improvement of the HTS maglev system.

  2. Fundamental vibrational mode in a highly inhomogeneous star

    OpenAIRE

    Bastrukov, S. I.; Chang, H. -K.; Wu, E. -H.; Molodtsova, I. V.

    2008-01-01

    The eigenfrequency problem of fundamental vibrational mode in a highly inhomogeneous star, modeled by self-gravitating mass of viscous liquid with singular density at the center, is considered in juxtaposition with that for Kelvin fundamental mode in the liquid star model with uniform density. Particular attention is given to the difference between spectral equations for the frequency and lifetime of f-mode in the singular and homogeneous star models. The newly obtained results are discussed ...

  3. Dose equations for shift-variant CT acquisition modes using variable pitch, tube current, and aperture, and the meaning of their associated CTDI{sub vol}

    Energy Technology Data Exchange (ETDEWEB)

    Dixon, Robert L., E-mail: rdixon@wfubmc.edu [Department of Radiology, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157 (United States); Boone, John M. [Departments of Radiology and Biomedical Engineering, University of California Davis, Sacramento, California 95817 (United States); Kraft, Robert A. [Department of Biomedical Engineering, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157 (United States)

    2014-11-01

    Purpose: With the increasing clinical use of shift-variant CT protocols involving tube current modulation (TCM), variable pitch or pitch modulation (PM), and variable aperture a(t), the interpretation of the scanner-reported CTDI{sub vol} is called into question. This was addressed for TCM in their previous paper published by Dixon and Boone [Med. Phys. 40, 111920 (14pp.) (2013)] and is extended to PM and concurrent TCM/PM as well as variable aperture in this work. Methods: Rigorous convolution equations are derived to describe the accumulated dose distributions for TCM, PM, and concurrent TCM/PM. A comparison with scanner-reported CTDI{sub vol} formulae clearly identifies the source of their differences with the traditional CTDI{sub vol}. Dose distribution simulations using the convolution are provided for a variety of TCM and PM scenarios including a helical shuttle used for perfusion studies (as well as constant mA)—all having the same scanner-reported CTDI{sub vol}. These new convolution simulations for TCM are validated by comparison with their previous discrete summations. Results: These equations show that PM is equivalent to TCM if the pitch variation p(z) is proportional to 1/i(z), where i(z) is the local tube current. The simulations show that the local dose at z depends only weakly on the local tube current i(z) or local pitch p(z) due to scatter from all other locations along z, and that the “local CTDI{sub vol}(z)” or “CTDI{sub vol} per slice” do not represent a local dose but rather only a relative i(z) or p(z). The CTDI-paradigm does not apply to shift-variant techniques and the scanner-reported CTDI{sub vol} for the same lacks physical significance and relevance. Conclusions: While the traditional CTDI{sub vol} at constant tube current and pitch conveys useful information (the peak dose at the center of the scan length), CTDI{sub vol} for shift-variant techniques (TCM or PM) conveys no useful information about the associated dose

  4. High order vector mode coupling mechanism based on mode matching method

    Science.gov (United States)

    Zhang, Zhishen; Gan, Jiulin; Heng, Xiaobo; Li, Muqiao; Li, Jiong; Xu, Shanhui; Yang, Zhongmin

    2017-06-01

    The high order vector mode (HOVM) coupling mechanism is investigated based on the mode matching method (MMM). In the case of strong HOVM coupling where the weakly guiding approximation fails, conventional coupling analysis methods become invalid due to the asynchronous coupling feature of the horizontal and vertical polarization components of HOVM. The MMM, which uses the interference of the local eigenmodes instead of the assumptive modes to simulate the light propagation, is adopted as a more efficient analysis method for investigating HOVM coupling processes, especially for strong coupling situations. The rules of the optimal coupling length, coupling efficiency, and mode purity in microfiber directional coupler are firstly quantitatively analyzed and summarized. Different from the specific input modes, some special new modes would be excited at the output through the strong HOVM coupling process. The analysis of HOVM coupling mechanism based on MMM could provide precise and accurate design guidance for HOVM directional coupler and mode converter, which are believed to be fundamental devices for multi-mode communication applications.

  5. On the possibility of a place code for the low pitch of high-frequency complex tones

    DEFF Research Database (Denmark)

    Santurette, Sébastien; Dau, Torsten; Oxenham, Andrew J.

    2012-01-01

    on pitch matches, and (3) listeners’ ability to hear out the individual components. No effects of relative component phase or dichotic presentation on pitch matches were found in the tested conditions. Large individual differences were found in listeners’ ability to hear out individual components. Overall......, the results are consistent with the coding of individual harmonic frequencies, based on the tonotopic activity pattern or phase locking to individual harmonics, rather than with temporal coding of single-channel interactions. However, they are also consistent with more general temporal theories of pitch...

  6. Highly efficient high power single-mode fiber amplifier utilizing the distributed mode filtering bandgap rod fiber

    DEFF Research Database (Denmark)

    Laurila, Marko; Alkeskjold, Thomas T.; Jørgensen, Mette Marie

    2012-01-01

    We report on an ytterbium doped single mode distributed mode filtering rod fiber in an amplifier configuration delivering high average output power, up to 292 watts, using a mode-locked 30ps source at 1032nm with good power conversion efficiency. We study the modal stability of the output beam...... at high average output power levels and demonstrate a 44% power improvement before the threshold-like onset of mode instabilities by operating the rod fiber in a leaky waveguide regime. We investigate the guiding dynamics of the rod fiber and explain the improved performance by thermally induced...

  7. Pitch Perfect: How Fruit Flies Control their Body Pitch Angle

    CERN Document Server

    Whitehead, Samuel C; Canale, Luca; Cohen, Itai

    2015-01-01

    Flapping insect flight is a complex and beautiful phenomenon that relies on fast, active control mechanisms to counter aerodynamic instability. To directly investigate how freely-flying D. melanogaster control their body pitch angle against such instability, we perturb them using impulsive mechanical torques and film their corrective maneuvers with high-speed video. Combining experimental observations and numerical simulation, we find that flies correct for pitch deflections of up to 40 degrees in 29 +/- 8 ms by bilaterally modulating their wings' front-most stroke angle in a manner well-described by a linear proportional-integral (PI) controller. Flies initiate this corrective process after only 10 +/- 2 ms, indicating that pitch stabilization involves a fast reflex response. Remarkably, flies can also correct for very large-amplitude pitch perturbations--greater than 150 degrees--providing a regime in which to probe the limits of the linear-response framework. Together with previous studies regarding yaw an...

  8. Pitch perception beyond the traditional existence region of pitch

    DEFF Research Database (Denmark)

    Oxenham, Andrew J.; Micheyl, Christophe; Keebler, Michael V.

    2011-01-01

    Humans’ ability to recognize musical melodies is generally limited to pure-tone frequencies below 4 or 5 kHz. This limit coincides with the highest notes on modern musical instruments and is widely believed to reflect the upper limit of precise stimulusdriven spike timing in the auditory nerve. We...... tested the upper limits of pitch and melody perception in humans using pure and harmonic complex tones, such as those produced by the human voice and musical instruments, in melody recognition and pitchmatching tasks. We found that robust pitch perception can be elicited by harmonic complex tones...... with fundamental frequencies below 2 kHz, even when all of the individual harmonics are above 6 kHz—well above the currently accepted existence region of pitch and above the currently accepted limits of neural phase locking. The results suggest that the perception of musical pitch at high frequencies...

  9. Tone language fluency impairs pitch discrimination

    Directory of Open Access Journals (Sweden)

    Isabelle ePeretz

    2011-07-01

    Full Text Available Here we present evidence that native speakers of a tone language, in which pitch contributes to word meaning, are impaired in the discrimination of falling pitches in tone sequences, as compared to speakers of a non-tone language. Both groups were presented with monotonic and isochronous sequences of five tones (i.e., constant pitch and intertone interval. They were required to detect when the fourth tone was displaced in pitch or time. While speakers of a tone language performed more poorly in the detection of downward pitch changes, they did not differ from non-tone language speakers in their perception of upward pitch changes or in their perception of subtle time changes. Moreover, this impairment cannot be attributed to low musical aptitude since the impairment remains unchanged when individual differences in musical pitch-based processing is taken into account. Thus, the impairment appears highly specific and may reflect the influence of statistical regularities of tone languages.

  10. High-pitch computed tomography pulmonary angiography with iterative reconstruction at 80 kVp and 20 mL contrast agent volume

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Guang Ming; Luo, Song; Zhou, Chang Sheng; Kong, Xiang; Zhao, Yan E.; Zheng, Ling; Zhang, Long Jiang [Jinling Hospital, Medical School of Nanjing University, Department of Medical Imaging, Nanjing, Jiangsu (China); Meinel, Felix G.; McQuiston, Andrew D. [Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States); Schoepf, U.J. [Jinling Hospital, Medical School of Nanjing University, Department of Medical Imaging, Nanjing, Jiangsu (China); Medical University of South Carolina, Department of Radiology and Radiological Science, Charleston, SC (United States)

    2014-12-15

    To evaluate the image quality, radiation dose and diagnostic accuracy of 80kVp, high-pitch CT pulmonary angiography (CTPA) with iterative reconstruction using 20 ml of contrast agent. One hundred patients with suspected pulmonary embolism (PE) were randomly divided into two groups (n = 50 each; group A, 100 kVp, 1.2 pitch, 60 ml of contrast medium and filtered back projection algorithm; group B, 80 kVp, 2.2 pitch, 20 ml of contrast medium and sinogram affirmed iterative reconstruction). Image quality, diagnostic accuracy and radiation dose were evaluated and compared. Mean CT numbers of pulmonary arteries in group B were higher than those in group A (all P < 0.001). Contrast-to-noise ratio and signal-to-noise ratio of group B were higher than those of group A (both P < 0.001). There was no significant difference in subjective image quality scores between two groups (P = 0.807). The interobserver agreement was excellent (k = 0.836). There was no significant difference in diagnostic accuracy between the two groups (P > 0.05). Compared with group A, radiation dose of group B was reduced by 50.3 % (P < 0.001). High-pitch CTPA at 80 kVp can obtain sufficient image quality in normal-weight individuals with 20 ml of contrast agent and half the radiation dose of a conventional CTPA protocol. (orig.)

  11. Image quality of ultra-low radiation exposure coronary CT angiography with an effective dose <0.1 mSv using high-pitch spiral acquisition and raw data-based iterative reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Schuhbaeck, Annika; Achenbach, Stephan; Hecker, Franziska; Rixe, Johannes [University of Giessen, Department of Cardiology, Giessen (Germany); Layritz, Christian; Eisentopf, Jasmin; Pflederer, Tobias; Gauss, Soeren; Kalender, Willi; Daniel, Werner G.; Lell, Michael; Ropers, Dieter [University of Erlangen, Departments of Cardiology and Radiology, Erlangen (Germany)

    2013-03-15

    We evaluated the potential of prospectively ECG-triggered high-pitch spiral acquisition with low tube voltage and current in combination with iterative reconstruction to achieve coronary CT angiography with sufficient image quality at an effective dose below 0.1 mSv. Contrast-enhanced coronary dual source CT angiography (2 x 128 x 0.6 mm, 80 kV, 50 mAs) in prospectively ECG-triggered high-pitch spiral acquisition mode was performed in 21 consecutive individuals (body weight <100 kg, heart rate {<=}60/min). Images were reconstructed with raw data-based filtered back projection (FBP) and iterative reconstruction (IR). Image quality was assessed on a 4-point scale (1 = no artefacts, 4 = unevaluable). Mean effective dose was 0.06 {+-} 0.01 mSv. Image noise was significantly reduced in IR (128.9 {+-} 46.6 vs. 158.2 {+-} 44.7 HU). The mean image quality score was lower for IR (1.9 {+-} 1.1 vs. 2.2 {+-} 1.0, P < 0.0001). Of 292 coronary segments, 55 in FBP and 40 in IR (P = 0.12) were graded ''unevaluable''. In patients with a body weight {<=}75 kg, both in FBP and in IR, the rates of fully evaluable segments were significantly higher in comparison to patients >75 kg. Coronary CT angiography with an estimated effective dose <0.1 mSv may provide sufficient image quality in selected patients through the combination of high-pitch spiral acquisition and raw data-based iterative reconstruction. (orig.)

  12. Development of a 55 μm pitch 8 inch CMOS image sensor for the high resolution NDT application

    Science.gov (United States)

    Kim, M. S.; Kim, G.; Cho, G.; Kim, D.

    2016-11-01

    A CMOS image sensor (CIS) with a large area for the high resolution X-ray imaging was designed. The sensor has an active area of 125 × 125 mm2 comprised with 2304 × 2304 pixels and a pixel size of 55 × 55 μm2. First batch samples were fabricated by using an 8 inch silicon CMOS image sensor process with a stitching method. In order to evaluate the performance of the first batch samples, the electro-optical test and the X-ray test after coupling with an image intensifier screen were performed. The primary results showed that the performance of the manufactured sensors was limited by a large stray capacitance from the long path length between the analog multiplexer on the chip and the bank ADC on the data acquisition board. The measured speed and dynamic range were limited up to 12 frame per sec and 55 dB respectively, but other parameters such as the MTF, NNPS and DQE showed a good result as designed. Based on this study, the new X-ray CIS with ~ 50 μm pitch and ~ 150 cm2 active area are going to be designed for the high resolution X-ray NDT equipment for semiconductor and PCB inspections etc.

  13. High power and single mode quantum cascade lasers.

    Science.gov (United States)

    Bismuto, Alfredo; Bidaux, Yves; Blaser, Stéphane; Terazzi, Romain; Gresch, Tobias; Rochat, Michel; Muller, Antoine; Bonzon, Christopher; Faist, Jerome

    2016-05-16

    We present a single mode quantum cascade laser with nearly 1 W optical power. A buried distributed feedback reflector is used on the back section for wavelength selection. The laser is 6 mm long, 3.5 μm wide, mounted episide-up and the laser facets are left uncoated. Laser emission is centered at 4.68 μm. Single-mode operation with a side mode suppression ratio of more than 30 dB is obtained in whole range of operation. Farfield measurements prove a symmetric, single transverse-mode emission in TM00-mode with typical divergences of 41° and 33° in the vertical and horizontal direction respectively. This work shows the potential for simple fabrication of high power lasers compatible with standard DFB processing.

  14. Discharge current modes of high power impulse magnetron sputtering

    Directory of Open Access Journals (Sweden)

    Zhongzhen Wu

    2015-09-01

    Full Text Available Based on the production and disappearance of ions and electrons in the high power impulse magnetron sputtering plasma near the target, the expression of the discharge current is derived. Depending on the slope, six possible modes are deduced for the discharge current and the feasibility of each mode is discussed. The discharge parameters and target properties are simplified into the discharge voltage, sputtering yield, and ionization energy which mainly affect the discharge plasma. The relationship between these factors and the discharge current modes is also investigated.

  15. Cortical pitch response components index stimulus onset/offset and dynamic features of pitch contours

    Science.gov (United States)

    Krishnan, Ananthanarayan; Gandour, Jackson T.; Ananthakrishnan, Saradha; Vijayaraghavan, Venkatakrishnan

    2014-01-01

    Voice pitch is an important information-bearing component of language that is subject to experience dependent plasticity at both early cortical and subcortical stages of processing. We’ve already demonstrated that pitch onset component (Na) of the cortical pitch response (CPR) is sensitive to flat pitch and its salience. In regards to dynamic pitch, we do not yet know whether the multiple pitch-related transient components of the CPR reflect specific temporal attributes of such stimuli. Here we examine the sensitivity of the multiple transient components of CPR to changes in pitch acceleration associated with the Mandarin high rising lexical tone. CPR responses from Chinese listeners were elicited by three citation forms varying in pitch acceleration and duration. Results showed that the pitch onset component (Na) was invariant to changes in acceleration. In contrast, Na-Pb and Pb-Nb showed a systematic increase in the interpeak latency and decrease in amplitude with increase in pitch acceleration that followed the time course of pitch change across the three stimuli. A strong correlation with pitch acceleration was observed for these two components only – a putative index of pitch-relevant neural activity associated with the more rapidly-changing portions of the pitch contour. Pc-Nc marks unambiguously the stimulus offset. We therefore propose that in the early stages of cortical sensory processing, a series of neural markers flag different temporal attributes of a dynamic pitch contour: onset of temporal regularity (Na); changes in temporal regularity between onset and offset (Na-Pb, Pb-Nb); and offset of temporal regularity (Pc-Nc). At the temporal electrode sites, the stimulus with the most gradual change in pitch acceleration evoked a rightward asymmetry. Yet within the left hemisphere, stimuli with more gradual change were indistinguishable. These findings highlight the emergence of early hemispheric preferences and their functional roles as related to

  16. High-Power Microwave Transmission and Mode Conversion Program

    Energy Technology Data Exchange (ETDEWEB)

    Vernon, Ronald J. [Univ. of Wisconsin, Madison, WI (United States)

    2015-08-14

    This is a final technical report for a long term project to develop improved designs and design tools for the microwave hardware and components associated with the DOE Plasma Fusion Program. We have developed basic theory, software, fabrication techniques, and low-power measurement techniques for the design of microwave hardware associated gyrotrons, microwave mode converters and high-power microwave transmission lines. Specifically, in this report we discuss our work on designing quasi-optical mode converters for single and multiple frequencies, a new method for the analysis of perturbed-wall waveguide mode converters, perturbed-wall launcher design for TE0n mode gyrotrons, quasi-optical traveling-wave resonator design for high-power testing of microwave components, and possible improvements to the HSX microwave transmission line.

  17. Effects of high modes on the wind-induced response of super high-rise buildings

    Science.gov (United States)

    Feng, Ruoqiang; Yan, Guirong; Ge, Jinming

    2012-09-01

    For super high-rise buildings, the vibration period of the basic mode is several seconds, and it is very close to the period of the fluctuating wind. The damping of super high-rise buildings is low, so super high-rise buildings are very sensitive to fluctuating wind. The wind load is one of the key loads in the design of super high-rise buildings. It is known that only the basic mode is needed in the wind-response analysis of tall buildings. However, for super high-rise buildings, especially for the acceleration response, because of the frequency amplification of the high modes, the high modes and the mode coupling may need to be considered. Three typical super high-rise projects with the SMPSS in wind tunnel tests and the random vibration theory method were used to analyze the effect of high modes on the wind-induced response. The conclusions can be drawn as follows. First, for the displacement response, the basic mode is dominant, and the high modes can be neglected. Second, for the acceleration response, the high modes and the mode coupling should be considered. Lastly, the strain energy of modes can only give the vibration energy distribution of the high-rise building, and it cannot describe the local wind-induced vibration of high-rise buildings, especially for the top acceleration response.

  18. Reflective dual-mode liquid crystal display possessing low power consumption and high contrast ratio under ambient light.

    Science.gov (United States)

    Kim, Taehyung; Lee, Joong Ha; Yoon, Tae-Hoon; Choi, Suk-Won

    2012-07-02

    We propose a reflective dual-mode liquid crystal display (RD-LCD) which has advantages of long memory retention time and high contrast ratio. The proposed device adopts ideal bistable characteristics, a cell thickness over pitch (d/p) of 0.25. It can realize long memory retention time, thereby reducing power consumption. In addition, an optical configuration for the RD-LCD makes low light leakages at dark state and shows good dispersion characteristics in both dark and bright states over the entire visible ranges. We experimentally confirmed retention time over 6 months in memory mode and memory and dynamic contrast ratios of 47:1 and 43:1 under ambient light, respectively. As a result, the proposed RD-LCD demonstrates convincingly that it is a candidate for green display.

  19. Evaluation of high-pitch dual-source CT angiography for evaluation of coronary and carotid-cerebrovascular arteries

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Kai [Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing 100053 (China); Li, Kuncheng, E-mail: cjr.likuncheng@vip.163.com [Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing 100053 (China); Han, Ruijuan [Department of Cardiology, Chaoyang Hospital, Capital Medical University, Beijing 100020 (China); Li, Wenhuan; Chen, Nan; Yang, Qi; Du, Xiangying; Wang, Chen [Department of Radiology, Xuanwu Hospital, Capital Medical University, Beijing 100053 (China); Liu, Guorong; Li, Yuechun [Department of Neurology Baotou Central Hospital, Inner Mongolia, Baotou 014040 (China); Zhou, Maorong [Department of Radiology, Baotou Central Hospital, Inner Mongolia, Baotou 014040 (China); Li, Ligang; Heidrun, Endt [CT BM Clinic Marketing, Siemens Healthcare, Beijing 100102 (China)

    2015-03-15

    Objectives: To explore the feasibility and diagnostic accuracy of a combined one-step high-pitch dual-source computed tomography angiography (CTA) technique for evaluation of coronary and carotid-cerebrovascular arteries. Materials and methods: 85 symptomatic patients suspected of coronary artery and cerebrovascular disease referred for simultaneous coronary and carotid-cerebrovascular CTA were included. Additional invasive angiography of the coronary and cerebral arteries was performed within 30 days in 23 and 13 patients, respectively. The objective parameters of image quality, the mean CT attenuations, image noise, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were evaluated. The subjective image quality of vessels was also assessed by 2 independent radiologists blinded to the patients’ medical history and scan protocols. The diagnostic performance of CTA including sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for the detection or exclusion of significant artery stenosis was calculated using the chi-squared test of contingency and correlated with the results of invasive angiography representing the standard of reference. Results: Image quality was rated excellent (score 1) in 95.3% (1074/1127), good (score 2) in 3.3% (37/1127), adequate (score 3) in 1.0% (11/1127), and non-diagnostic (score 4) in 0.4% (5/1127) of coronary segments. Image quality of carotid and cerebral vessels was rated mostly excellent (score 1, 95.12% [78/82]; score 2, 3.66% [3/82]; score 3, 1.22% [1/82]). The sensitivity, specificity, PPV and NPV for the detection of coronary stenosis were 92.2% (81.1–97.7%), 95.2% (91.7–97.5%), 79.6% (67.1–89.1%) and 98.3% (95.8–99.5%), respectively. For the detection of carotid and cerebral artery stenosis, CTA demonstrated a sensitivity of 92.8% (80.5–98.4%), a specificity of 93.5% (88.3–96.8%), a PPV of 79.6% (65.6–89.7%) and a NPV of 97.9% (94.1–99.5%). The effective

  20. Pitch and pitch variation in lesbian women.

    Science.gov (United States)

    Van Borsel, John; Vandaele, Jana; Corthals, Paul

    2013-09-01

    The purpose of this study was to investigate to what extent lesbian women demonstrate pitch and pitch variation that is different from that of heterosexual women. Static group comparison. The average pitch and pitch variation of a group of 34 self-identified lesbian women and an age-matched group of 68 heterosexual women were compared. The speech sample consisted of read speech. Acoustic analysis was performed by means of PRAAT. Mean fundamental frequency in the group of lesbian women was significantly lower than that of the group of heterosexual women. The lesbian woman also showed significantly less pitch variation. Lesbian women tend to demonstrate a lower average pitch and less pitch variation than heterosexual women, but this does not mean a confirmation of the popular stereotype that lesbian women are masculine women. In their assessment of clients with voice disorders, clinicians should reckon with the sociophonetic variation that is associated with sexual orientation. Copyright © 2013 The Voice Foundation. Published by Mosby, Inc. All rights reserved.

  1. Characteristics of high-confinement modes in Alcator C Mod

    Energy Technology Data Exchange (ETDEWEB)

    Snipes, J.A.; Boivin, R.L.; Christensen, C.; Fiore, C.; Garnier, D.; Goetz, J.; Golovato, S.N.; Graf, M.; Granetz, R.S.; Greenwald, M.; Hubbard, A.; Hutchinson, I.H.; Irby, J.; LaBombard, B.; Marmar, E.S.; Niemczewski, A.; OShea, P.; Porkolab, M.; Stek, P.; Takase, Y.; Terry, J.L.; Umansky, M.; Wolfe, S.M. [Plasma Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    1996-05-01

    The regime of high particle and energy confinement known as the H mode [Phys. Rev. Lett. {bold 49}, 1408 (1982)] has been extended to a unique range of operation for divertor tokamaks up to toroidal fields of nearly 8 T, line-averaged electron densities of 3{times}10{sup 20} m{sup {minus}3}, and surface power densities of nearly 0.6 MW/m{sup 2} in the compact high-field tokamak Alcator C Mod [Phys. Plasmas {bold 1}, 1511 (1994)]. H modes are achieved in Alcator C Mod with Ion Cyclotron Resonant Frequency (ICRF) heating and with Ohmic heating alone without boronization of the all molybdenum tiled first wall. Large increases in charge exchange flux are observed during the H mode over the entire range of energies from 2 to 10 keV. There appears to be an upper limit to the midplane neutral pressure, of about 0.08 Pa above which no H modes have been observed. The plasmas with the best energy confinement have the lowest midplane neutral pressures, below 0.01 Pa. There is an edge electron temperature threshold such that {ital T}{sub {ital e}}{ge}280 eV {plus_minus}40 eV for sustaining the H mode, which is equal at L{endash}H and H{endash}L transitions. The hysteresis in the threshold power between L{endash}H and H{endash}L transitions is less than 25{percent} on average. Both core and edge particle confinement improve by a factor of 2{endash}4 from L mode to H mode. Energy confinement also improves by up to a factor of 2 over L mode. {copyright} {ital 1996 American Institute of Physics.}

  2. Pitch perfect: how fruit flies control their body pitch angle.

    Science.gov (United States)

    Whitehead, Samuel C; Beatus, Tsevi; Canale, Luca; Cohen, Itai

    2015-11-01

    Flapping insect flight is a complex and beautiful phenomenon that relies on fast, active control mechanisms to counter aerodynamic instability. To directly investigate how freely flying Drosophila melanogaster control their body pitch angle against such instability, we perturbed them using impulsive mechanical torques and filmed their corrective maneuvers with high-speed video. Combining experimental observations and numerical simulation, we found that flies correct for pitch deflections of up to 40 deg in 29±8 ms by bilaterally modulating their wings' front-most stroke angle in a manner well described by a linear proportional-integral (PI) controller. Flies initiate this corrective process only 10±2 ms after the perturbation onset, indicating that pitch stabilization involves a fast reflex response. Remarkably, flies can also correct for very large-amplitude pitch perturbations--greater than 150 deg--providing a regime in which to probe the limits of the linear-response framework. Together with previous studies regarding yaw and roll control, our results on pitch show that flies' stabilization of each of these body angles is consistent with PI control. © 2015. Published by The Company of Biologists Ltd.

  3. The effect of intensity on relative pitch.

    Science.gov (United States)

    Thompson, William Forde; Peter, Varghese; Olsen, Kirk N; Stevens, Catherine J

    2012-01-01

    In two experiments, we examined the effect of intensity and intensity change on judgements of pitch differences or interval size. In Experiment 1, 39 musically untrained participants rated the size of the interval spanned by two pitches within individual gliding tones. Tones were presented at high intensity, low intensity, looming intensity (up-ramp), and fading intensity (down-ramp) and glided between two pitches spanning either 6 or 7 semitones (a tritone or a perfect fifth interval). The pitch shift occurred in either ascending or descending directions. Experiment 2 repeated the conditions of Experiment 1 but the shifts in pitch and intensity occurred across two discrete tones (i.e., a melodic interval). Results indicated that participants were sensitive to the differences in interval size presented: Ratings were significantly higher when two pitches differed by 7 semitones than when they differed by 6 semitones. However, ratings were also dependent on whether the interval was high or low in intensity, whether it increased or decreased in intensity across the two pitches, and whether the interval was ascending or descending in pitch. Such influences illustrate that the perception of pitch relations does not always adhere to a logarithmic function as implied by their musical labels, but that identical intervals are perceived as substantially different in size depending on other attributes of the sound source.

  4. Prelinguistic Infants Are Sensitive to Space-Pitch Associations Found Across Cultures

    NARCIS (Netherlands)

    Dolscheid, S.J.; Hunnius, S.; Casasanto, D.; Majid, A.

    2014-01-01

    People often talk about musical pitch using spatial metaphors. In English, for instance, pitches can be "high" or "low" (i.e., height-pitch association), whereas in other languages, pitches are described as "thin" or "thick" (i.e., thickness-pitch association). According to results from

  5. Guided-Mode-Leaky-Mode-Guided-Mode Fiber Interferometer and Its High Sensitivity Refractive Index Sensing Technology

    Directory of Open Access Journals (Sweden)

    Qi Wang

    2016-06-01

    Full Text Available A cascaded symmetrical dual-taper Mach-Zehnder interferometer structure based on guided-mode and leaky-mode interference is proposed in this paper. Firstly, the interference spectrum characteristics of interferometer has been analyzed by the Finite Difference-Beam Propagation Method (FD-BPM. When the diameter of taper waist is 20 μm–30 μm, dual-taper length is 1 mm and taper distance is 4 cm–6 cm, the spectral contrast is higher, which is suitable for sensing. Secondly, experimental research on refractive index sensitivity is carried out. A refractive index sensitivity of 62.78 nm/RIU (refractive index unit can achieved in the RI range of 1.3333–1.3792 (0%~25% NaCl solution, when the sensor structure parameters meet the following conditions: diameter of taper waist is 24 μm, dual-taper length is 837 μm and taper distance is 5.5 cm. The spectrum contrast is 0.8 and measurement resolution is 1.6 × 10−5 RIU. The simulation analysis is highly consistent with experimental results. Research shows that the sensor has promising application in low RI fields where high-precision measurement is required due to its high sensitivity and stability.

  6. Current barriers to confine high frequency common mode currents

    NARCIS (Netherlands)

    Moonen, Dominicus Johannes Guilielmus; Buesink, Frederik Johannes Karel; Leferink, Frank Bernardus Johannes

    2016-01-01

    A commercially produced three phase power line filter is submitted to a Current Barrier (CB) Electro-Magnetic Compatibility (EMC) zoning strategy as an attempt to confine high frequency common mode currents. The intent of the paper is not to show how to build a ’perfect’ filter, since this is known.

  7. A high performance switching audio amplifier using sliding mode control

    OpenAIRE

    Pillonnet, Gael; Cellier, Rémy; Abouchi, Nacer; Chiollaz, Monique

    2008-01-01

    International audience; The switching audio amplifiers are widely used in various portable and consumer electronics due to their high efficiency, but suffers from low audio performances due to inherent nonlinearity. This paper presents an integrated class D audio amplifier with low consumption and high audio performances. It includes a power stage and an efficient control based on sliding mode technique. This monolithic class D amplifier is capable of delivering up to 1W into 8Ω load at less ...

  8. Twist defect in chiral photonic structures with spatially varying pitch

    Science.gov (United States)

    Chen, Jiun-Yeu; Chen, Lien-Wen

    2005-04-01

    The properties of photonic defect modes in a chiral photonic structure were investigated using the finite element method. By stacking two cholesteric liquid crystal (ChLC) films, the defect mode due to the introduction of a twist defect was considered in both cases of chiral structures with constant pitch and spatially varying pitch. Two types of linear pitch gradients for achieving a broadband reflection were analysed, and the number of chiral pitches required for establishing the stop band was simulated. The effect of a finite sample thickness on the energy density distribution of the defect mode and on the required polarization of the incident light to excite the defect mode was studied. In both cases of constant pitch and spatially varying pitch, an unusual crossover behaviour in reflection at the defect resonance wavelength of a single circularly polarized mode appears when the structure thickness increases beyond a specific value. The energy distribution inside the sample also reveals the unusual distribution. Two different resonance wavelengths can be created by a twist defect in the ChLC composite film with linearly varying pitch, while only one resonance wavelength can be created in the identical film with constant pitch.

  9. High order shear horizontal modes for minimum remnant thickness.

    Science.gov (United States)

    Belanger, Pierre

    2014-04-01

    Thickness mapping in aging structures suffering from corrosion is challenging especially when the structure is only partially accessible. In plates the high order shear horizontal guided wave modes all have a cutoff frequency thickness product below which they cannot propagate. This property is potentially attractive to estimate the minimum remnant thickness between two transducers. When using a source and a sensor array it is possible to control the number of modes being excited and the size of the region interrogated by the technique. Finite element simulations were used to show that by exciting multiple guided wave modes simultaneously and identifying which modes are received by a sensor array it is possible to estimate the minimum remaining thickness along the propagation path. Initial experimental results showed excellent agreement with the finite element simulations when the plate is uniform and with a thickness reduction between the source and the sensor arrays the minimum remnant thickness was underestimated by approximately 20%. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. High-Energy Passive Mode-Locking of Fiber Lasers

    Directory of Open Access Journals (Sweden)

    Edwin Ding

    2012-01-01

    Full Text Available Mode-locking refers to the generation of ultrashort optical pulses in laser systems. A comprehensive study of achieving high-energy pulses in a ring cavity fiber laser that is passively mode-locked by a series of waveplates and a polarizer is presented in this paper. Specifically, it is shown that the multipulsing instability can be circumvented in favor of bifurcating to higher-energy single pulses by appropriately adjusting the group velocity dispersion in the fiber and the waveplate/polarizer settings in the saturable absorber. The findings may be used as practical guidelines for designing high-power lasers since the theoretical model relates directly to the experimental settings.

  11. Clinical application of high speed B mode echocardiography.

    Science.gov (United States)

    Kambe, T; Nishimura, K; Hibi, N; Sakakibara, T; Kato, T

    1977-06-01

    This study discusses the clinical application of high speed B mode echocardiography to a wide variety of heart diseases. We used a rapid mechanical sector scan at 30 frames per second and 120 scanning lines per frame, resulting in real time observation of cardiac structures. The sector angle was relatively wide (maximum 90 degrees). The tomograms were synchronized with the electrocardiogram and recorded on ordinary 35 mm or Polaroid film in conjunction with 8 mm cinematography. Heart cross sections could be recorded even in the presence of arrhythmia. We used a flat or focused, 10 mm diameter transducer made of lead zirconate-titanate with a resonant frequency of 2 or 3 MHz at a repetition rate of 3.6 kHz. High speed B mode echocardiography is a means of observing cross sections of the heart that can contribute to the improvement of accuracy in cardiac diagnosis.

  12. High Efficiency, High Linearity, Switch Mode Power Amplifiers for Varying envelop Signal Applications

    DEFF Research Database (Denmark)

    Tong, Tian; Sira, Daniel; Nielsen, Michael

    2009-01-01

    using switch-mode power amplifier aided by various linearization techniques can present a feasible way to achieve both high linearity and high power efficiency. In this paper two different implementations of the switch-mode power amplifier a re p resented for varying envelop applications: the RF pulse...

  13. Detection of coronary artery stenosis with sub-milliSievert radiation dose by prospectively ECG-triggered high-pitch spiral CT angiography and iterative reconstruction.

    Science.gov (United States)

    Yin, Wei-Hua; Lu, Bin; Hou, Zhi-Hui; Li, Nan; Han, Lei; Wu, Yong-Jian; Niu, Hong-Xia; Silverman, Justin R; Nicola De Cecco, Carlo; Schoepf, U Joseph

    2013-11-01

    To evaluate the diagnostic accuracy of sub-milliSievert (mSv) coronary CT angiography (cCTA) using prospectively ECG-triggered high-pitch spiral CT acquisition combined with iterative image reconstruction. Forty consecutive patients (52.9 ± 8.7 years; 30 men) underwent dual-source cCTA using prospectively ECG-triggered high-pitch spiral acquisition. The tube current-time product was set to 50 % of standard-of-care CT examinations. Images were reconstructed with sinogram-affirmed iterative reconstruction. Image quality was scored and diagnostic performance for detection of ≥50 % stenosis was determined with catheter coronary angiography (CCA) as the reference standard. CT was successfully performed in all 40 patients. Of the 601 assessable coronary segments, 543 (90.3 %) had diagnostic image quality. Per-patient sensitivity for detection of ≥50 % stenosis was 95.7 % [95 % confidence interval (CI), 76.0-99.8 %] and specificity was 94.1 % (95 % CI, 69.2-99.7 %). Per-vessel sensitivity was 89.5 % (95 % CI, 77.8-95.6 %) with 93.2 % specificity (95 % CI, 86.0-97.0 %). The area under the receiver-operating characteristic curve on per-patient and per-vessel levels was 0.949 and 0.913. Mean effective dose was 0.58 ± 0.17 mSv. Mean size-specific dose estimate was 3.14 ± 1.15 mGy. High-pitch prospectively ECG-triggered cCTA combined with iterative image reconstruction provides high diagnostic accuracy with a radiation dose below 1 mSv for detection of coronary artery stenosis. • Cardiac CT with sub-milliSievert radiation dose is feasible in many patients • High-pitch spiral CT acquisition with iterative reconstruction detects coronary stenosis accurately. • Iterative reconstruction increases who can benefit from low-radiation cardiac CT.

  14. Image quality of ultra-low-dose dual-source CT angiography using high-pitch spiral acquisition and iterative reconstruction in young children with congenital heart disease.

    Science.gov (United States)

    Zheng, Minwen; Zhao, Hongliang; Xu, Jian; Wu, Yongjie; Li, Jian

    2013-01-01

    Obtaining diagnostic CT image quality with ultra-low radiation dose in young children with congenital heart disease remains challenging. We evaluated the feasibility and image quality of prospectively electrocardiogram (ECG)-triggered high-pitch spiral acquisition with iterative reconstruction for pediatric cardiovascular CT angiography. Sixty-two consecutive pediatric patients younger than 2 years with congenital heart disease underwent prospectively ECG-triggered high-pitch spiral dual-source CT acquisition. Patients were randomly assigned into 2 groups: full tube current (40-70 mAs) scans with filtered back projection reconstruction (group A) and half tube current (20-35 mAs) scans with sinogram-affirmed iterative reconstruction (group B). Attenuation, noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and subjective image quality were compared between the 2 groups. Effective radiation dose was also estimated for both groups. No significant difference was found in the attenuation, image noise, SNR, and CNR between the 2 groups in the same evaluated anatomic regions, whereas the attenuation and image noise were slightly lower, and the SNR and CNR were slightly higher in group B. No significant difference was found in subjective image quality between the 2 groups (4.27 ± 0.73 vs. 4.34 ± 0.42; P = .813). Effective dose was 0.06 ± 0.03 mSv in group B and 0.13 ± 0.04 mSv in group A, reflecting dose savings of 53.8% by using iterative reconstruction. A combination of prospectively ECG-triggered high-pitch spiral acquisition, low tube current, and iterative reconstruction may offer diagnostic image quality in pediatric cardiovascular CT angiography with effective radiation dose < 0.1 mSv. Copyright © 2013 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.

  15. Feasibility of low-dose contrast medium high pitch CT angiography for the combined evaluation of coronary, head and neck arteries.

    Directory of Open Access Journals (Sweden)

    Zhiwei Wang

    Full Text Available PURPOSE: To evaluate the image quality and radiation dose of combined heart, head, and neck CT angiography (CTA using prospectively electrocardiography (ECG-triggered high-pitch spiral scan protocol, compared with single coronary CTA. MATERIALS AND METHODS: 151 consecutive patients were prospectively included and randomly divided into three groups. Group 1 (n = 47 underwent combined heart, neck, and head CTA using prospectively ECG-triggered high-pitch spiral (Flash scan protocol with a single-phase intravenous injection of iodinated contrast and saline flush; Group 2 (n = 51 underwent single coronary CTA with Flash scan protocol; and Group 3 (n = 53 underwent single coronary CTA with prospective sequence scan protocol. All patients were examined on a dual source CT (Definition FLASH. The image quality was determined for each CT study. RESULTS: Patients of scanning protocol Group 1, 2, and 3 showed no significant differences in age, sex, heart rates, and BMI. Evaluation of coronary artery image quality showed comparable results in the three scanning protocol groups on a per patient-based analysis. In group 1, image quality was found to be sufficient to be diagnostic in all arterial segments of carotid arteries. The mean dose-length product (DLP for group 1 was 256.3±24.5 mGy×cm and was significantly higher in comparison with group 2 (93.4±19.9 mGy×cm; p < 0.001. However, there was no significant difference of DLP between group 1 and group 3 (254.1±69.9 mGy×cm. CONCLUSIONS: The combined heart, neck, and head arteries scan using prospectively electrocardiography (ECG-triggered high-pitch spiral scan protocol in 1 single examination resulted in an excellent opacification of the aorta, the carotid arteries, and the coronary arteries and provided a good image quality with low radiation dose.

  16. Cone beam breast CT with a high pitch (75 μm), thick (500 μm) scintillator CMOS flat panel detector: Visibility of simulated microcalcifications

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Youtao; Zhong, Yuncheng; Lai, Chao-Jen; Wang, Tianpeng; Shaw, Chris C. [Department of Imaging Physics, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030 (United States)

    2013-10-15

    Purpose: To measure and investigate the improvement of microcalcification (MC) visibility in cone beam breast CT with a high pitch (75 μm), thick (500 μm) scintillator CMOS/CsI flat panel detector (Dexela 2923, Perkin Elmer).Methods: Aluminum wires and calcium carbonate grains of various sizes were embedded in a paraffin cylinder to simulate imaging of calcifications in a breast. Phantoms were imaged with a benchtop experimental cone beam CT system at various exposure levels. In addition to the Dexela detector, a high pitch (50 μm), thin (150 μm) scintillator CMOS/CsI flat panel detector (C7921CA-09, Hamamatsu Corporation, Hamamatsu City, Japan) and a widely used low pitch (194 μm), thick (600 μm) scintillator aSi/CsI flat panel detector (PaxScan 4030CB, Varian Medical Systems) were also used in scanning for comparison. The images were independently reviewed by six readers (imaging physicists). The MC visibility was quantified as the fraction of visible MCs and measured as a function of the estimated mean glandular dose (MGD) level for various MC sizes and detectors. The modulation transfer functions (MTFs) and detective quantum efficiencies (DQEs) were also measured and compared for the three detectors used.Results: The authors have demonstrated that the use of a high pitch (75 μm) CMOS detector coupled with a thick (500 μm) CsI scintillator helped make the smaller 150–160, 160–180, and 180–200 μm MC groups more visible at MGDs up to 10.8, 9, and 10.8 mGy, respectively. It also made the larger 200–212 and 212–224 μm MC groups more visible at MGDs up to 7.2 mGy. No performance improvement was observed for 224–250 μm or larger size groups. With the higher spatial resolution of the Dexela detector based system, the apparent dimensions and shapes of MCs were more accurately rendered. The results show that with the aforementioned detector, a 73% visibility could be achieved in imaging 160–180 μm MCs as compared to 28% visibility achieved by

  17. Dial A440 for absolute pitch: absolute pitch memory by non-absolute pitch possessors.

    Science.gov (United States)

    Smith, Nicholas A; Schmuckler, Mark A

    2008-04-01

    Listeners without absolute (or "perfect") pitch have difficulty identifying or producing isolated musical pitches from memory. Instead, they process the relative pattern of pitches, which remains invariant across pitch transposition. Musically untrained non-absolute pitch possessors demonstrated absolute pitch memory for the telephone dial tone, a stimulus that is always heard at the same absolute frequency. Listeners accurately classified pitch-shifted versions of the dial tone as "normal," "higher than normal" or "lower than normal." However, the role of relative pitch processing was also evident, in that listeners' pitch judgments were also sensitive to the frequency range of stimuli.

  18. High source levels and small active space of high-pitched song in bowhead whales (Balaena mysticetus.

    Directory of Open Access Journals (Sweden)

    Outi M Tervo

    Full Text Available The low-frequency, powerful vocalizations of blue and fin whales may potentially be detected by conspecifics across entire ocean basins. In contrast, humpback and bowhead whales produce equally powerful, but more complex broadband vocalizations composed of higher frequencies that suffer from higher attenuation. Here we evaluate the active space of high frequency song notes of bowhead whales (Balaena mysticetus in Western Greenland using measurements of song source levels and ambient noise. Four independent, GPS-synchronized hydrophones were deployed through holes in the ice to localize vocalizing bowhead whales, estimate source levels and measure ambient noise. The song had a mean apparent source level of 185±2 dB rms re 1 µPa @ 1 m and a high mean centroid frequency of 444±48 Hz. Using measured ambient noise levels in the area and Arctic sound spreading models, the estimated active space of these song notes is between 40 and 130 km, an order of magnitude smaller than the estimated active space of low frequency blue and fin whale songs produced at similar source levels and for similar noise conditions. We propose that bowhead whales spatially compensate for their smaller communication range through mating aggregations that co-evolved with broadband song to form a complex and dynamic acoustically mediated sexual display.

  19. Perfect pitch reconsidered.

    Science.gov (United States)

    Moulton, Calum

    2014-10-01

    Perfect pitch, or absolute pitch (AP), is defined as the ability to identify or produce the pitch of a sound without need for a reference pitch, and is generally regarded as a valuable asset to the musician. However, there has been no recent review of the literature examining its aetiology and its utility taking into account emerging scientific advances in AP research, notably in functional imaging. This review analyses the key empirical research on AP, focusing on genetic and neuroimaging studies. The review concludes that: AP probably has a genetic predisposition, although this is based on limited evidence; early musical training is almost certainly essential for AP acquisition; and, although there is evidence that it may be relevant to speech processing, AP can interfere with relative pitch, an ability on which humans rely to communicate effectively. The review calls into question the value of AP to musicians and non-musicians alike. © 2014 Royal College of Physicians.

  20. Octave bias in an absolute pitch identification task

    OpenAIRE

    Boschetti, Giulia; Prpic, Valter; De Tommaso, Matteo; Murgia, Mauro; Agostini, Tiziano

    2014-01-01

    Octave errors are common within musicians, even among absolute pitch possessors. Overall, evidence shows pitch class and octave to be perceived in a different way, even if they are highly connected. We investigated whether pitch class perception, in an absolute pitch identification task, can be influenced by the octave context, examined among two consecutive octaves. Participants, all musicians with formal musical education, showed different response patterns in the tw...

  1. Memory for Melody: Infants Use a Relative Pitch Code

    Science.gov (United States)

    Plantinga, Judy; Trainor, Laurel J.

    2005-01-01

    Pitch perception is fundamental to melody in music and prosody in speech. Unlike many animals, the vast majority of human adults store melodic information primarily in terms of relative not absolute pitch, and readily recognize a melody whether rendered in a high or a low pitch range. We show that at 6 months infants are also primarily relative…

  2. Intravenous contrast material administration at high-pitch dual-source CT pulmonary angiography: Test bolus versus bolus-tracking technique

    Energy Technology Data Exchange (ETDEWEB)

    Kerl, J. Matthias, E-mail: matthias.kerl@gmail.com [Institute for Diagnostic and Interventional Radiology, Clinic of the Goethe University, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany); Lehnert, Thomas, E-mail: Thomas.lehnert@kgu.de [Institute for Diagnostic and Interventional Radiology, Clinic of the Goethe University, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany); Schell, Boris, E-mail: boris.schell@googlemail.com [Institute for Diagnostic and Interventional Radiology, Clinic of the Goethe University, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany); Bodelle, Boris, E-mail: Boris.bodelle@kgu.de [Institute for Diagnostic and Interventional Radiology, Clinic of the Goethe University, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany); Beeres, Martin, E-mail: Martin.Beeres@kgu.de [Institute for Diagnostic and Interventional Radiology, Clinic of the Goethe University, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany); Jacobi, Volkmar, E-mail: v.jacobi@em.uni-frankfurt.de [Institute for Diagnostic and Interventional Radiology, Clinic of the Goethe University, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany); Vogl, Thomas J., E-mail: T.Vogl@em.uni-frankfurt.de [Institute for Diagnostic and Interventional Radiology, Clinic of the Goethe University, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany); Bauer, Ralf W., E-mail: ralfwbauer@aol.com [Institute for Diagnostic and Interventional Radiology, Clinic of the Goethe University, Theodor-Stern-Kai 7, 60590 Frankfurt (Germany)

    2012-10-15

    Purpose: To compare test bolus and bolus tracking for the determination of scan delay of high-pitch dual-source CT pulmonary angiography in patients with suspected pulmonary embolism using 50 ml of contrast material. Materials and methods: Data of 80 consecutive patients referred for CT pulmonary angiography were evaluated. All scans were performed on a 128-channel dual-source CT scanner with a high-pitch protocol (pitch 3.0, 100 kV, 180 mA s). Contrast enhancement was achieved by injecting 50 ml of iomeprol followed by a saline chaser of 50 ml injected at a rate of 4 ml/s. The scan delay was determined using either the test bolus (n = 40) or bolus tracking (n = 40) technique. Test bolus required another 15 ml CM to determine time to peak enhancement of the contrast bolus within the pulmonary trunk. Attenuation profiles in the pulmonary trunk and on segmental level as well as in the ascending aorta were measured to evaluate the timing techniques. Additionally, overall image quality was evaluated. Results: In all patients an adequate and homogeneous contrast enhancement of more than 250 HU was achieved in the pulmonary arteries. No statistically significant difference between test bolus and bolus tracking was found regarding attenuation of the pulmonary arteries or overall image quality. However, using bolus tracking 15 ml CM less was injected. Conclusion: A homogeneous opacification of the pulmonary arteries and sufficient image quality can be achieved with both the bolus tracking and test bolus techniques with significant lower contrast doses compared to conventional contrast material injection protocols.

  3. Mode locking of fiber lasers at high repetition rates

    Science.gov (United States)

    Usechak, Nicholas G.

    Mode-locked fiber lasers have become indispensable tools in many fields as their use is no longer relegated to the optics community. In the future, their size will decrease and their applications will become far more prevalent than they are today. At present, the field is undergoing a cardinal shift as these devices have become commercially available in the last decade. This has put an emphasis on long-term performance and reliability as these devices are beginning to be integrated into complex systems in areas as diverse as medical optics, micro-machining, forensics, and tracking as well as their obvious use as laboratory tools or sources in telecommunications. This is also resulting in a transition from research to engineering. Since the field of mode-locked lasers has been extensively studied for over forty years, one may expect that little has been overlooked. However, since the mode-locking phenomena is governed by nonlinear partial differential equations, a rich degree of effects exist and the field has not yet been exhausted. During the past two decades, the main emphasis has been on short-pulse generation; however, the main thrust of research is likely to change to producing high-power devices, which will result in limiting effects and thermal issues that are currently ignored for low-power sources. Finally, detailed studies have generally been performed numerically as analytic solutions only exist in limiting cases. In this thesis, mode-locked fiber lasers are studied experimentally, numerically, and theoretically. The experimental work focuses on high-repetition rate, mode-locked cavities, which are then modeled numerically. A semi-analytic tool, which goes beyond the prior theories and includes all of the effects experienced by steady-state, mode-locked pulses as they propagate in a laser cavity, is also derived. The only caveats to this approach are an assumption of the pulse shape and the requirement that it not change during propagation through the

  4. Diagnostic image quality of a comprehensive high-pitch dual-spiral cardiothoracic CT protocol in patients with undifferentiated acute chest pain

    Energy Technology Data Exchange (ETDEWEB)

    Bamberg, Fabian, E-mail: fbamberg@med.lmu.de [Department of Clinical Radiology, Ludwig-Maximilians University, Klinikum Grosshadern, Munich (Germany); Marcus, Roy; Sommer, Wieland; Schwarz, Florian; Nikolaou, Konstantin; Becker, Christoph R.; Reiser, Maximilian F.; Johnson, Thorsten R.C. [Department of Clinical Radiology, Ludwig-Maximilians University, Klinikum Grosshadern, Munich (Germany)

    2012-12-15

    Objective: To evaluate diagnostic image quality of high-pitch dual source comprehensive cardiothoracic CT protocol in patients presenting with acute undifferentiated chest pain. Materials and methods: Consecutive symptomatic subjects (n = 51) with undifferentiated acute chest pain underwent ECG-synchronized high-pitch dual-spiral chest CT angiography (Definition Flash, Siemens Medical Solutions, 2 × 100 kVp or 2 × 120 kV if BMI > 30, collimation: 128 × 0.6 mm, pitch: 3.2). Independent investigators determined the image quality of each cardiac and pulmonary vessel segment, measured contrast-to-noise-ratio (CNR), and determined radiation exposure. In addition, the prevalence of CT findings (pulmonary embolism (PE), aortic dissection (AD) and significant coronary stenosis (≥50%)) was determined. Univariate and multivariate analysis were performed to determine the subpopulation with highest diagnostic quality. Results: Among 51 subjects (66% male, average age: 63 ± 15.8), the prevalence of positive CT findings was moderate (overall: 11.7%). Overall, image quality of the pulmonary, aortic and coronary vasculature was good (1.26 ± 0.43 and CNR: 2.52) with an average radiation dose of 3.82 mSv and 3.2% of segments rated non-evaluable. The image quality was lowest in the coronary arteries (p = 0.02), depending on the heart rate (r = 0.52, p < 0.001). In subjects with a heart rate of ≤65 bpm (n = 30) subjective image quality and CNR of the coronary arteries were higher (1.6 ± 0.5 vs. 2.1 ± 0.5, p = 0.03 and 1.21 ± 0.3 vs. 1.02 ± 0.3, p = 0.05) with only 1.5% segments classified as non-evaluable. Conclusion: High-pitch dual-spiral comprehensive cardiothoracic CT provides low radiation exposure with excellent image quality at heart rates ≤65 bpm. In subjects with higher heart rates, image quality of the aortic and pulmonary vasculature remains excellent, while the assessment of the coronary arteries degrades substantially.

  5. Spatial Mode Control of High-Order Harmonics

    Energy Technology Data Exchange (ETDEWEB)

    Mercer, I.; Mevel, E.; Zerne, R.; LHuillier, A.; Antoine, P.; Wahlstroem, C. [Department of Physics, Lund Institute of Technology, S-221 00 Lund (Sweden)]|[Commissariat a l`Energie Atomique, DSM/DRECAM/SPAM, Centre d`Etudes de Saclay, 91191 Gif-sur-Yvette (France)

    1996-08-01

    We demonstrate that the spatial mode of high-order harmonics can be continuously controlled. The control is achieved by spatially modulating the degree of elliptical polarization of the fundamental field using birefringent optics. A highly sensitive relationship between the efficiency of harmonic generation and the degree of laser elliptical polarization leads to atoms emitting harmonics only in regions of linear polarization. The harmonics are emitted as annular beams whose angles of divergence can be continuously varied. {copyright} {ital 1996 The American Physical Society.}

  6. Processing and characterization of high resolution GaN/InGaN LED arrays at 10 micron pitch for micro display applications

    Science.gov (United States)

    Dupré, Ludovic; Marra, Marjorie; Verney, Valentin; Aventurier, Bernard; Henry, Franck; Olivier, François; Tirano, Sauveur; Daami, Anis; Templier, François

    2017-02-01

    We report the fabrication process and characterization of high resolution 873 x 500 pixels emissive arrays based on blue or green GaN/InGaN light emitting diodes (LEDs) at a reduced pixel pitch of 10 μm. A self-aligned process along with a combination of damascene metallization steps is presented as the key to create a common cathode which is expected to provide good thermal dissipation and prevent voltage drops between center and side of the micro LED matrix. We will discuss the challenges of a self-aligned technology related to the choice of a good P contact metal and will present our solutions for the realization of the metallic interconnections between the GaN contacts and the higher levels of metallization at such a small pixel pitch. Enhanced control of each technological step allows scalability of the process up to 4 inch LED wafers and production of high quality LED arrays. The very high brightness (up to 107 cd.m-2) and good external quantum efficiency (EQE) of the resulting device make these kind of micro displays suitable for augmented reality or head up display applications.

  7. High-Q Supercavity Modes in Subwavelength Dielectric Resonators.

    Science.gov (United States)

    Rybin, Mikhail V; Koshelev, Kirill L; Sadrieva, Zarina F; Samusev, Kirill B; Bogdanov, Andrey A; Limonov, Mikhail F; Kivshar, Yuri S

    2017-12-15

    Recent progress in nanoscale optical physics is associated with the development of a new branch of nanophotonics exploring strong Mie resonances in dielectric nanoparticles with a high refractive index. The high-index resonant dielectric nanostructures form building blocks for novel photonic metadevices with low losses and advanced functionalities. However, unlike extensively studied cavities in photonic crystals, such dielectric resonators demonstrate low quality factors (Q factors). Here, we uncover a novel mechanism for achieving giant Q factors of subwavelength nanoscale resonators by realizing the regime of bound states in the continuum. In contrast to the previously suggested multilayer structures with zero permittivity, we reveal strong mode coupling and Fano resonances in homogeneous high-index dielectric finite-length nanorods resulting in high-Q factors at the nanoscale. Thus, high-index dielectric resonators represent the simplest example of nanophotonic supercavities, expanding substantially the range of applications of all-dielectric resonant nanophotonics and meta-optics.

  8. Image quality and radiation dose of lower extremity CT angiography using 70 kVp, high pitch acquisition and sinogram-affirmed iterative reconstruction.

    Directory of Open Access Journals (Sweden)

    Li Qi

    Full Text Available OBJECTIVES: The purpose of this study was to assess image quality and radiation dose of lower extremity CT angiography (CTA with 70 kVp, high pitch acquisition and sinogram-affirmed iterative reconstruction (SAFIRE. METHODS: Lower extremity CTAs were performed on 44 patients: 22 patients were examined using protocol A (120 kVp, pitch of 0.85 and 120 ml of contrast agent on a first-generation dual-source CT (120 kVp group and 22 patients were evaluated with protocol B (70 kVp, pitch of 2.2 and 80 ml of contrast agent on a second-generation dual-source CT (70 kVp group. Images from the 120 kVp group were reconstructed with filtered back projection (FBP and images from the 70 kVp group with SAFIRE. The attenuation, image noise, signal-to-noise ratio (SNR and contrast-to-noise ratio (CNR were calculated. Two radiologists subjectively assessed image quality of lower extremity arteries, plantar arterial enhancement and venous contamination of all patients. Radiation dose was compared between the two groups. RESULTS: Higher mean intravascular attenuation was obtained in the 70 kVp group (70 vs. 120 kVp group, 555.4 ± 83.4 HU vs. 300.9 ± 81.4 HU, P0.05. The venous contamination score was 1.5 ± 0.8 for 120 kVp group while no venous contamination was found in 70 kVp group. The inter-observer agreement was moderate to good for both groups (0.515∼1, P<0.001. The effective dose was lower in 70 kVp group (0.3 ± 0.1 mSv than in 120 kVp group (1.6 ± 0.7 mSv(P<0.001. CONCLUSIONS: Lower extremity CTA using 70 kVp, high pitch acquisition and SAFIRE, except increasing imaging noise, allows for lower radiation dose and contrast material volume without compromising image quality.

  9. Major League Baseball pitch velocity and pitch type associated with risk of ulnar collateral ligament injury.

    Science.gov (United States)

    Keller, Robert A; Marshall, Nathan E; Guest, John-Michael; Okoroha, Kelechi R; Jung, Edward K; Moutzouros, Vasilios

    2016-04-01

    The number of Major League Baseball (MLB) pitchers requiring ulnar collateral ligament (UCL) reconstructions is increasing. Recent literature has attempted to correlate specific stresses placed on the throwing arm to risk for UCL injury, with limited results. Eighty-three MLB pitchers who underwent primary UCL reconstruction were evaluated. Pitching velocity and percent of pitch type thrown (fastball, curve ball, slider, and change-up) were evaluated 2 years before and after surgery. Data were compared with control pitchers matched for age, position, size, innings pitched, and experience. The evaluation of pitch velocity compared with matched controls found no differences in pre-UCL reconstruction pitch velocities for fastballs (91.5 vs. 91.2 miles per hour [mph], P = .69), curveballs (78.2 vs. 77.9 mph, P = .92), sliders (83.3 vs. 83.5 mph, P = .88), or change-ups (83.9 vs. 83.8 mph, P = .96). When the percentage of pitches thrown was evaluated, UCL reconstructed pitchers pitch significantly more fastballs than controls (46.7% vs. 39.4%, P = .035). This correlated to a 2% increase in risk for UCL injury for every 1% increase in fastballs thrown. Pitching more than 48% fastballs was a significant predictor of UCL injury, because pitchers over this threshold required reconstruction (P = .006). MLB pitchers requiring UCL reconstruction do not pitch at higher velocities than matched controls, and pitch velocity does not appear to be a risk factor for UCL reconstruction. However, MLB pitchers who pitch a high percentage of fastballs may be at increased risk for UCL injury because pitching a higher percent of fastballs appears to be a risk factor for UCL reconstruction. Copyright © 2016 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  10. Impaired pitch identification as a potential marker for depression.

    Science.gov (United States)

    Schwenzer, Michael; Zattarin, Eva; Grözinger, Michael; Mathiak, Klaus

    2012-04-19

    Impaired auditory performance has been considered as marker for depression. The present study tested whether pitch perception is affected in depression and whether the impairment is task-specific or reflects global dysfunction. Twelve depressive in-patients and 12 non-depressive participants, half of the sample women, volunteered. The participants performed pitch identification using a four-choice reaction task, pitch contour perception, and pitch discrimination. During pitch identification but not during pitch contour perception or pitch discrimination, depressive patients responded less accurate than non-depressive participants (F = 3.3, p = 0.047). An analysis of covariates revealed that only female but not male depressive patients identified pitches poorly (Z = -2.2, p = 0.025) and inaccurate pitch identification correlated with high scores in the Beck Depression Inventory in women (r = -0.8, p = 0.001) but not in men (r = -0.1, p = 0.745). Patients did not differ from controls in reaction time or responsiveness. Impaired pitch perception in depression is task-specific. Therefore, cognitive deficits in depression are circumscribed and not global. Reduced pitch identification in depression was associated with female sex. We suggest that impaired pitch identification merits attention as a potential marker for depression in women.

  11. Impaired pitch identification as a potential marker for depression

    Directory of Open Access Journals (Sweden)

    Schwenzer Michael

    2012-04-01

    Full Text Available Abstract Background Impaired auditory performance has been considered as marker for depression. The present study tested whether pitch perception is affected in depression and whether the impairment is task-specific or reflects global dysfunction. Methods Twelve depressive in-patients and 12 non-depressive participants, half of the sample women, volunteered. The participants performed pitch identification using a four-choice reaction task, pitch contour perception, and pitch discrimination. Results During pitch identification but not during pitch contour perception or pitch discrimination, depressive patients responded less accurate than non-depressive participants (F = 3.3, p = 0.047. An analysis of covariates revealed that only female but not male depressive patients identified pitches poorly (Z = −2.2, p = 0.025 and inaccurate pitch identification correlated with high scores in the Beck Depression Inventory in women (r = −0.8, p = 0.001 but not in men (r = −0.1, p = 0.745. Patients did not differ from controls in reaction time or responsiveness. Conclusions Impaired pitch perception in depression is task-specific. Therefore, cognitive deficits in depression are circumscribed and not global. Reduced pitch identification in depression was associated with female sex. We suggest that impaired pitch identification merits attention as a potential marker for depression in women.

  12. Consonance and pitch.

    Science.gov (United States)

    McLachlan, Neil; Marco, David; Light, Maria; Wilson, Sarah

    2013-11-01

    To date, no consensus exists in the literature as to theories of consonance and dissonance. Experimental data collected over the last century have raised questions about the dominant theories that are based on frequency relationships between the harmonics of music chords. This study provides experimental evidence that strongly challenges these theories and suggests a new theory of dissonance based on relationships between pitch perception and recognition. Experiment 1 shows that dissonance does not increase with increasing numbers of harmonics in chords as predicted by Helmholtz's (1863/1954) roughness theory, nor does it increase with fewer pitch-matching errors as predicted by Stumpf's (1898) tonal fusion theory. Dissonance was strongly correlated with pitch-matching error for chords, which in turn was reduced by chord familiarity and greater music training. This led to the proposition that long-term memory templates for common chords assist the perception of pitches in chords by providing an estimate of the chord intervals from spectral information. When recognition mechanisms based on these templates fail, the spectral pitch estimate is inconsistent with the period of the waveform, leading to cognitive incongruence and the negative affect of dissonance. The cognitive incongruence theory of dissonance was rigorously tested in Experiment 2, in which nonmusicians were trained to match the pitches of a random selection of 2-pitch chords. After 10 training sessions, they rated the chords they had learned to pitch match as less dissonant than the unlearned chords, irrespective of their tuning, providing strong support for a cognitive mechanism of dissonance. PsycINFO Database Record (c) 2013 APA, all rights reserved.

  13. Sensitivity of the cortical pitch onset response to height, time-variance, and directionality of dynamic pitch.

    Science.gov (United States)

    Bidelman, Gavin M

    2015-08-31

    Event-related brain potentials (ERPs) demonstrate that human auditory cortical responses are sensitive to changes in static pitch as indexed by the pitch onset response (POR), a negativity generated at the initiation of acoustic periodicity. Yet, it is still unclear if this brain signature is sensitive to dynamic, time-varying properties of pitch more characteristic of those found in naturalistic speech and music. Neuroelectric PORs were recorded in response to contrastive pitch patterns differing in their pitch height, time-variance, and directionality (i.e., rise vs. fall). Broadband noise followed by contiguous iterated rippled noise (producing salient pitch sweeps) was used to temporally separate neural activity coding the onset of acoustic energy from the onset of time-varying pitch. Analysis of PORs revealed distinct modulations in response latency that distinguished static from time-varying pitch contours (steady-statepitch height (highpitch sweeps (rise=fall). Our findings suggest that the POR signature provides a useful neural index of auditory cortical pitch processing for some, but not all pitch-evoking stimuli. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  14. Digitally Programmable High-Q Voltage Mode Universal Filter

    Directory of Open Access Journals (Sweden)

    D. Singh

    2013-12-01

    Full Text Available A new low-voltage low-power CMOS current feedback amplifier (CFA is presented in this paper. This is used to realize a novel digitally programmable CFA (DPCFA using transistor arrays and MOS switches. The proposed realizations nearly allow rail-to-rail swing capability at all the ports. Class-AB output stage ensures low power dissipation and high current drive capability. The proposed CFA/ DPCFA operates at supply voltage of ±0.75 V and exhibits bandwidth better than 95 MHz. An application of the DPCFA to realize a novel voltage mode high-Q digitally programmable universal filter (UF is given. Performances of all the proposed circuits are verified by PSPICE simulation using TSMC 0.25μm technology parameters.

  15. Rigorous study of supercontinuum generation by high-order optical modes

    Science.gov (United States)

    Ben Salem, Amine; Trichili, Abderrahmen; Cherif, Rim; Zghal, Mourad

    2016-09-01

    We numerically study the supercontinuum (SC) generation in a six modes photonic crystal fiber (PCF). By solving the multimode generalised Schrdinger equation, we demonstrate the generation of SC by initially exciting the fundamental mode or one of the higher order modes and then observe the energy transfer to the other high order modes. We analyze the energy transfer between degenerate modes during propagation through the few mode PCF. A detailed investigation of the nonlinear effects on the SC process through linear and nonlinear coupling is provided which confirms the energy transfer between optical degenerate modes during propagation inside the few- mode fiber.

  16. Variable Pitch Darrieus Water Turbines

    Science.gov (United States)

    Kirke, Brian; Lazauskas, Leo

    In recent years the Darrieus wind turbine concept has been adapted for use in water, either as a hydrokinetic turbine converting the kinetic energy of a moving fluid in open flow like an underwater wind turbine, or in a low head or ducted arrangement where flow is confined, streamtube expansion is controlled and efficiency is not subject to the Betz limit. Conventional fixed pitch Darrieus turbines suffer from two drawbacks, (i) low starting torque and (ii) shaking due to cyclical variations in blade angle of attack. Ventilation and cavitation can also cause problems in water turbines when blade velocities are high. Shaking can be largely overcome by the use of helical blades, but these do not produce large starting torque. Variable pitch can produce high starting torque and high efficiency, and by suitable choice of pitch regime, shaking can be minimized but not entirely eliminated. Ventilation can be prevented by avoiding operation close to a free surface, and cavitation can be prevented by limiting blade velocities. This paper summarizes recent developments in Darrieus water turbines, some problems and some possible solutions.

  17. Mode of conception of triplets and high order multiple pregnancies.

    LENUS (Irish Health Repository)

    Basit, I

    2012-03-01

    A retrospective audit was performed of all high order multiple pregnancies (HOMPs) delivered in three maternity hospitals in Dublin between 1999 and 2008. The mode of conception for each pregnancy was established with a view to determining means of reducing their incidence. A total of 101 HOMPs occurred, 93 triplet, 7 quadruplet and 1 quintuplet. Information regarding the mode of conception was available for 78 (81%) pregnancies. Twenty eight (27.7%) were spontaneous, 34 (33.7%) followedlVF\\/ICSI\\/FET treatment (in-vitro fertilisation, intracytoplasmic sperm injection, frozen embryo transfer), 16 (15.8%) resulted from Clomiphene Citrate treatment and 6 (6%) followed ovulation induction with gonadotrophins. Triplet and HOMPs are a major cause of maternal, feta land neonatal morbidity. Many are iatrogenic, arising from fertility treatments including Clomiphene. Reducing the numbers of embryos transferred will address IVF\\/ICSI\\/FET-related multiple pregnancy rates and this is currently happening in Ireland. Clomiphene and gonadotrophins should only be prescribed when appropriate resources are available to monitor patients adequately.

  18. High-m Kink/Tearing Modes in Cylindrical Geometry

    CERN Document Server

    Connor, J W; Pusztai, I; Catto, P J; Barnes, M

    2014-01-01

    The global ideal kink equation, for cylindrical geometry and zero beta, is simplified in the high poloidal mode number limit and used to determine the tearing stability parameter, $\\Delta^\\prime$. In the presence of a steep monotonic current gradient, $\\Delta^\\prime$ becomes a function of a parameter, $\\sigma_0$, characterising the ratio of the maximum current gradient to magnetic shear, and $x_s$, characterising the separation of the resonant surface from the maximum of the current gradient. In equilibria containing a current "spike", so that there is a non-monotonic current profile, $\\Delta^\\prime$ also depends on two parameters: $\\kappa$, related to the ratio of the curvature of the current density at its maximum to the magnetic shear, and $x_s$, which now represents the separation of the resonance from the point of maximum current density. The relation of our results to earlier studies of tearing modes and to recent gyro-kinetic calculations of current driven instabilities, is discussed, together with pot...

  19. Application of 70 kV Third-generation High-pitch Dual-source Coronary CT Angiography in Patients with Different Body Mass Index.

    Science.gov (United States)

    Yi, Yan; Cao, Jian; Lin, Lu; Kong, Lingyan; Jiang, Shu; Li, Xiao; Liu, Peijun; Wang, Ming; Wang, Man; Wang, Yun; Jin, Zhengyu; Wang, Yining

    2017-02-20

    Objective  To investigate the optimized range of body mass index (BMI) selection for patients undergoing 70 kV high-pitch dual-source coronary CT angiography (CCTA) on the third-generation dual-source CT (DSCT). Methods  Patients undergoing prospective high-pitch ultra-low contrast media (CM) CCTA on the third-generation DSCT using the automatic tube voltage selection at 70 kV were included and divided into three groups:group A,with BMI≤24 kg/m2;group B,with 24 kg/m2image quality results,and effective dose (ED) were evaluated and compared. Results  No significant difference was found in age (H=2.36,P=0.78),heart rate (H=3.51,P=0.80),and ED(H=1.77,P=0.12) among three groups. The noise of the aortic root in group A was (21.66±4.00)HU,which was significantly lower than that in group C [(23.61±4.20)HU](F=2.05,P=0.03). The signal to noise ratio of aortic root in group A (18.61±5.28) was significantly better than that in group C (14.75±2.58) (F=5.31,P=0.02). No other significant difference in quantitative image quality were found among the three groups (all P >0.05). Subjective image quality in group A(Z=2.91,P=0.004) and B(Z=2.27,P=0.021) were both significantly better than that in group C. Conclusion  The ultra-low tube voltage (70 kV) combined with ultra-low CM CCTA protocol on third-generation high-pitch DSCT may be better for patients with BMI<28 kg/m2 than those with BMI ≥28 kg/m2 in China.

  20. Dynamo Enhancement and Mode Selection Triggered by High Magnetic Permeability

    Science.gov (United States)

    Kreuzahler, S.; Ponty, Y.; Plihon, N.; Homann, H.; Grauer, R.

    2017-12-01

    We present results from consistent dynamo simulations, where the electrically conducting and incompressible flow inside a cylinder vessel is forced by moving impellers numerically implemented by a penalization method. The numerical scheme models jumps of magnetic permeability for the solid impellers, resembling various configurations tested experimentally in the von Kármán sodium experiment. The most striking experimental observations are reproduced in our set of simulations. In particular, we report on the existence of a time-averaged axisymmetric dynamo mode, self-consistently generated when the magnetic permeability of the impellers exceeds a threshold. We describe a possible scenario involving both the turbulent flow in the vicinity of the impellers and the high magnetic permeability of the impellers.

  1. Whispering-gallery mode resonators for highly unidirectional laser action

    Science.gov (United States)

    Wang, Qi Jie; Yan, Changling; Yu, Nanfang; Unterhinninghofen, Julia; Wiersig, Jan; Pflügl, Christian; Diehl, Laurent; Edamura, Tadataka; Yamanishi, Masamichi; Kan, Hirofumi; Capasso, Federico

    2010-01-01

    Optical microcavities can be designed to take advantage of total internal reflection, which results in resonators supporting whispering-gallery modes (WGMs) with a high-quality factor (Q factor). One of the crucial problems of these devices for practical applications such as designing microcavity lasers, however, is that their emission is nondirectional due to their radial symmetry, in addition to their inefficient power output coupling. Here we report the design of elliptical resonators with a wavelength-size notch at the boundary, which support in-plane highly unidirectional laser emission from WGMs. The notch acts as a small scatterer such that the Q factor of the WGMs is still very high. Using midinfrared (λ ∼ 10 μm) injection quantum cascade lasers as a model system, an in-plane beam divergence as small as 6 deg with a peak optical power of ∼5 mW at room temperature has been demonstrated. The beam divergence is insensitive to the pumping current and to the notch geometry, demonstrating the robustness of this resonator design. The latter is scalable to the visible and the near infrared, thus opening the door to very low-threshold, highly unidirectional microcavity diode lasers. PMID:21149678

  2. Analyses of mode filling factor of a laser end-pumped by a LD with high-order transverse modes

    Science.gov (United States)

    Han, Juhong; Wang, You; An, Guofei; Rong, Kepeng; Yu, Hang; Wang, Shunyan; Zhang, Wei; Cai, He; Xue, Liangping; Wang, Hongyuan; Zhou, Jie

    2017-05-01

    Although the concept of the mode filling factor (also named as "mode-matching efficiency") has been well discussed decades before, the concept of so-called overlap coefficient is often confused by the laser technicians because there are several different formulae for various engineering purposes. Furthermore, the LD-pumped configurations have become the mainstream of solid-state lasers since their compact size, high optical-to-optical efficiency, low heat generation, etc. As the beam quality of LDs are usually very unsatisfactory, it is necessary to investigate how the mode filling factor of a laser system is affected by a high-powered LD pump source. In this paper, theoretical analyses of an end-pumped laser are carried out based on the normalized overlap coefficient formalism. The study provides a convenient tool to describe the intrinsically complex issue of mode interaction corresponding to a laser and an end-pumped source. The mode filling factor has been studied for many cases in which the pump mode and the laser mode have been considered together in the calculation based on analyses of the rate equations. The results should be applied for analyses of any other types of lasers with the similar optical geometry.

  3. Thoraco-abdominal high-pitch dual-source CT angiography: Experimental evaluation of injection protocols with an anatomical human vascular phantom

    Energy Technology Data Exchange (ETDEWEB)

    Puippe, Gilbert D., E-mail: gilbert.puippe@usz.ch [Institute for Diagnostic and Interventional Radiology, University Hospital Zurich, Switzerland Raemistrasse 100, CH-8091 Zurich (Switzerland); Winklehner, Anna [Institute for Diagnostic and Interventional Radiology, University Hospital Zurich, Switzerland Raemistrasse 100, CH-8091 Zurich (Switzerland); Hasenclever, Peter; Plass, André [Division of Cardiac and Vascular Surgery, University Hospital Zurich, Switzerland Raemistrasse 100, CH-8091 Zurich (Switzerland); Frauenfelder, Thomas; Baumueller, Stephan [Institute for Diagnostic and Interventional Radiology, University Hospital Zurich, Switzerland Raemistrasse 100, CH-8091 Zurich (Switzerland)

    2012-10-15

    Objective: To experimentally evaluate three different contrast injection protocols at thoraco-abdominal high-pitch dual-source computed tomography angiography (CTA), with regard to level and homogeneity of vascular enhancement at different cardiac outputs. Materials and methods: A uniphasic, a biphasic as well as an individually tailored contrast protocol were tested using a human vascular phantom. Each protocol was scanned at 5 different cardiac outputs (3–5 L/min, steps of 0.5 L/min) using an extracorporeal cardiac pump. Vascular enhancement of the thoraco-abdominal aorta was measured every 5 cm. Overall mean enhancement of each protocol and mean enhancement for each cardiac output within each protocol were calculated. Enhancement homogeneity along the z-axis was evaluated for each cardiac output and protocol. Results: Overall mean enhancement was significantly higher in the uniphasic than in the other two protocols (all p < .05), whereas the difference between the biphasic and tailored protocol was not significant (p = .76). Mean enhancement among each of the 5 cardiac outputs within each protocol was significantly different (all p < .05). Only within the tailored protocol mean enhancement differed not significantly at cardiac outputs of 3.5 L/min vs. 5 L/min (484 ± 25 HU vs. 476 ± 19 HU, p = .14) and 4 vs. 5 L/min (443 ± 49 HU vs. 476 ± 19 HU, p = .05). Both, uniphasic and tailored protocol yielded homogenous enhancement at all cardiac outputs, whereas the biphasic protocol failed to achieve homogenous enhancement. Conclusion: This phantom study suggests that diagnostic and homogenous enhancement at thoraco-abdominal high-pitch dual-source CTA is feasible with either a uniphasic or an individually tailored contrast protocol.

  4. The Designs of High Efficiency Launcher of Quasi-Optical Mode Converter for High Power Gyrotrons

    Science.gov (United States)

    Minami, R.; Kasugai, A.; Takahashi, K.; Kobayashi, N.; Mitsunaka, Y.; Sakamoto, K.

    2006-01-01

    A high efficiency launcher of quasi-optical (QO) mode converters for high power gyrotrons have been designed and tested. A helical cut launcher radiates the RF power via its straight cut onto the first phase correcting mirror. The launchers have been optimized for the TE31.8 mode at 170 GHz and TE22.6 mode at 110 GHz by numerically optimizing a launcher surface. The helical cut of the launcher has been optimized by taking the taper angle into account. Further more, the amplitude of the surface perturbation have been optimized for improved focusing in order to reduce the diffraction losses at the helical cut. Low power measurement shows a good agreement with the design. High efficiency characteristics of the design have also been calculated on the assumption of frequency downshift due to the thermal expansion of the cavity and stepwise frequency tuning by changing the operating mode. Besides, the possibility of high efficiency launcher for higher mode is discussed, and these results give the prospect to high efficiency long pulse gyrotrons.

  5. High-intensity pulsed beam source with tunable operation mode

    Science.gov (United States)

    Nashilevskiy, A. V.; Kanaev, G. G.; Ezhov, V. V.; Shamanin, V. I.

    2017-05-01

    The report presents the design of an electron and an ion pulsed accelerator. The powerful high-voltage pulse generator of the accelerator and the vacuum bushing insulator is able to change the polarity of the output voltage. The low-inductance matching transformer provides an increase in the DFL output impedance by 4 times. The generator based on a high voltage pulse transformer and a pseudo spark switch is applied for DFL charging. The high-impedance magnetically insulated focusing diode with Br magnetic field and the “passive” anode was used to realize the ion beam generation mode. The plasma is formed on the surface of the anode caused by an electrical breakdown at the voltage edge pulse; as a result, the carbon ion and proton beam is generated. This beam has the following parameters: the current density is about 400 A/cm2 (in focus): the applied voltage is up to 450 kV. The accelerator is designed for the research on the interaction of the charged particle pulsed beams with materials and for the development of technological processes of a material modification.

  6. Pitch Based Sound Classification

    DEFF Research Database (Denmark)

    Nielsen, Andreas Brinch; Hansen, Lars Kai; Kjems, U

    2006-01-01

    -max output function. Both linear and quadratic inputs are used. The model is trained on 2 hours of sound and tested on publicly available data. A test classification error below 0.05 with 1 s classification windows is achieved. Further more it is shown that linear input performs as well as a quadratic......A sound classification model is presented that can classify signals into music, noise and speech. The model extracts the pitch of the signal using the harmonic product spectrum. Based on the pitch estimate and a pitch error measure, features are created and used in a probabilistic model with soft......, and that even though classification gets marginally better, not much is achieved by increasing the window size beyond 1 s....

  7. Wind turbine pitch optimization

    DEFF Research Database (Denmark)

    Biegel, Benjamin; Juelsgaard, Morten; Stoustrup, Jakob

    2011-01-01

    We consider a static wind model for a three-bladed, horizontal-axis, pitch-controlled wind turbine. When placed in a wind field, the turbine experiences several mechanical loads, which generate power but also create structural fatigue. We address the problem of finding blade pitch profiles......% compared to any constant pitch profile while sacrificing at most 7% of the maximum attainable output power. Using iterative learning, we show that very similar performance can be achieved by using only load measurements, with no knowledge of the wind field or wind turbine model....... for maximizing power production while simultaneously minimizing fatigue loads. In this paper, we show how this problem can be approximately solved using convex optimization. When there is full knowledge of the wind field, numerical simulations show that force and torque RMS variation can be reduced by over 96...

  8. Pitch matching psychometrics in electric acoustic stimulation.

    Science.gov (United States)

    Baumann, Uwe; Rader, Tobias; Helbig, Silke; Bahmer, Andreas

    2011-01-01

    Combined electric-acoustic stimulation (EAS) is a therapeutic option for patients with severe to profound mid- and high-frequency hearing loss while low-frequency hearing is mostly unaffected. The present study investigates bimodal pitch matching in EAS users as a function of the angular placement of electrodes. Results are compared with data obtained from previous pitch matching studies. Knowledge of electric and acoustic pitch mapping may be important for effective fitting to control the frequency range of acoustic and electric processing. Pitch adjustment experiments were conducted in eight subjects with residual hearing in the opposite ear as well as in the implanted ear. Four subjects received a standard 31.5-mm electrode array and four subjects received the shorter, more flexible 24-mm FLEX electrode array (PULSARCI100 or SONATATI100 stimulator, MED-EL, Innsbruck, Austria). The subjects' task was to listen to single-electrode stimuli presented at a fixed rate (800 pulses per second) via the cochlear implant and to adjust the frequency of the acoustic stimulus until the perceived pitch matched the perception of the electrically conveyed stimulus. Two to four of the most apical electrodes were tested depending on the range of the individual's residual hearing. Postoperative x rays (modified Stenver's view) were analyzed to compare individual pitch matching data in terms of the electrode arrays' insertion angle. The average mean frequency match for the most apical electrode 1 in EAS subjects implanted with the FLEX array was 583 Hz, while for the two subjects with a deep insertion of the 31.5-mm standard electrode array, the matches were 128 and 223 Hz. Because the residual hearing in the EAS subgroup was rather limited in the high-frequency range, a limited number of basal electrodes were assessed to determine the slope of the electric place/pitch function. A considerable variation in terms of the individual pitch function was observed. The slope of the pitch

  9. Automated tube voltage selection in thoracoabdominal computed tomography at high pitch using a third-generation dual-source scanner: image quality and radiation dose performance.

    Science.gov (United States)

    Lurz, Markus; Lell, Michael M; Wuest, Wolfgang; Eller, Achim; Scharf, Michael; Uder, Michael; May, Matthias Stefan

    2015-05-01

    The objective of this study was to evaluate the radiation dose and image quality performance of thoracoabdominal examinations with an automated tube voltage selection (tube voltage adaptation), tube current modulation, and high pitch using a third-generation dual-source computed tomography (CT) compared intraindividually with 120-kV examinations with tube current modulation with special attention on clinically relevant lesions in the liver, the lungs, and extrahepatic soft tissues. This study was approved by the institutional review board. Computed tomography of the body was performed using a third-generation dual-source system in 95 patients (mean body mass index, 25 kg/m²; range, 18-35 kg/m²). For 49 of these patients, all calculated tube settings and resulting dose values were recorded for each of the 12 gradual contrast weightings of the tube voltage adaptation algorithm. Spiral CT was performed for all patients with an intermediate weighting (grade 7) in a portal venous phase at 120 reference kV, 180 reference mAs, and pitch of 1.55. Objective image quality was assessed on the basis of contrast-to-noise ratio. Subjective image quality was assessed on the basis of clarity and sharpness of anatomical and pathological structures as well as interfering beam hardening and spiral and motion artifacts (heart, lungs, diaphragm). Previous examinations on a 64-slice scanner served as reference. All examinations were rated good or excellent for clinical diagnosis. Automated tube voltage selection resulted in significantly lower effective radiation dose (9.5 mSv) compared with the reference (12.0 mSv; P radiation dose reduction while substantially increasing the image quality, even at large-volume exposure.

  10. Ultra High Mode Mix in NIF NIC Implosions

    Science.gov (United States)

    Scott, Robbie; Garbett, Warren

    2017-10-01

    This work re-examines a sub-set of the low adiabat implosions from the National Ignition Campaign in an effort to better understand potential phenomenological sources of `excess' mix observed experimentally. An extensive effort has been made to match both shock-timing and backlit radiography (Con-A) implosion data in an effort to reproduce the experimental conditions as accurately as possible. Notably a 30% reduction in ablation pressure at peak drive is required to match the experimental data. The reduced ablation pressure required to match the experimental data allows the ablator to decompress, in turn causing the DT ice-ablator interface to go Rayleigh-Taylor unstable early in the implosion acceleration phase. Post-processing the runs with various mix models indicates high-mode mix from the DT ice-ablator interface may penetrate deep into the hotspot. This work offers a potential explanation of why these low-adiabat implosions exhibited significantly higher levels of mix than expected from high-fidelity multi-dimensional simulations. Through this new understanding, a possible route forward for low-adiabat implosions on NIF is suggested.

  11. Minimum component high frequency current mode rectifier | Sampe ...

    African Journals Online (AJOL)

    In this paper a current mode full wave rectifier circuit is proposed. The current mode rectifier circuit is implemented utilizing a floating current source (FCS) as an active element. The minimum component full wave rectifier utilizes only a single floating current source, two diodes and two grounded resistors. The extremely ...

  12. Impact of gain saturation on the mode instability threshold in high-power fiber amplifiers

    DEFF Research Database (Denmark)

    Hansen, Kristian Rymann; Lægsgaard, Jesper

    2014-01-01

    We present a coupled-mode model of transverse mode instability in high-power fiber amplifiers, which takes the effect of gain saturation into account. The model provides simple semi-analytical formulas for the mode instability threshold, which are valid also for highly saturated amplifiers...

  13. Effects of culture on musical pitch perception.

    Science.gov (United States)

    Wong, Patrick C M; Ciocca, Valter; Chan, Alice H D; Ha, Louisa Y Y; Tan, Li-Hai; Peretz, Isabelle

    2012-01-01

    The strong association between music and speech has been supported by recent research focusing on musicians' superior abilities in second language learning and neural encoding of foreign speech sounds. However, evidence for a double association--the influence of linguistic background on music pitch processing and disorders--remains elusive. Because languages differ in their usage of elements (e.g., pitch) that are also essential for music, a unique opportunity for examining such language-to-music associations comes from a cross-cultural (linguistic) comparison of congenital amusia, a neurogenetic disorder affecting the music (pitch and rhythm) processing of about 5% of the Western population. In the present study, two populations (Hong Kong and Canada) were compared. One spoke a tone language in which differences in voice pitch correspond to differences in word meaning (in Hong Kong Cantonese, /si/ means 'teacher' and 'to try' when spoken in a high and mid pitch pattern, respectively). Using the On-line Identification Test of Congenital Amusia, we found Cantonese speakers as a group tend to show enhanced pitch perception ability compared to speakers of Canadian French and English (non-tone languages). This enhanced ability occurs in the absence of differences in rhythmic perception and persists even after relevant factors such as musical background and age were controlled. Following a common definition of amusia (5% of the population), we found Hong Kong pitch amusics also show enhanced pitch abilities relative to their Canadian counterparts. These findings not only provide critical evidence for a double association of music and speech, but also argue for the reconceptualization of communicative disorders within a cultural framework. Along with recent studies documenting cultural differences in visual perception, our auditory evidence challenges the common assumption of universality of basic mental processes and speaks to the domain generality of culture

  14. Effects of culture on musical pitch perception.

    Directory of Open Access Journals (Sweden)

    Patrick C M Wong

    Full Text Available The strong association between music and speech has been supported by recent research focusing on musicians' superior abilities in second language learning and neural encoding of foreign speech sounds. However, evidence for a double association--the influence of linguistic background on music pitch processing and disorders--remains elusive. Because languages differ in their usage of elements (e.g., pitch that are also essential for music, a unique opportunity for examining such language-to-music associations comes from a cross-cultural (linguistic comparison of congenital amusia, a neurogenetic disorder affecting the music (pitch and rhythm processing of about 5% of the Western population. In the present study, two populations (Hong Kong and Canada were compared. One spoke a tone language in which differences in voice pitch correspond to differences in word meaning (in Hong Kong Cantonese, /si/ means 'teacher' and 'to try' when spoken in a high and mid pitch pattern, respectively. Using the On-line Identification Test of Congenital Amusia, we found Cantonese speakers as a group tend to show enhanced pitch perception ability compared to speakers of Canadian French and English (non-tone languages. This enhanced ability occurs in the absence of differences in rhythmic perception and persists even after relevant factors such as musical background and age were controlled. Following a common definition of amusia (5% of the population, we found Hong Kong pitch amusics also show enhanced pitch abilities relative to their Canadian counterparts. These findings not only provide critical evidence for a double association of music and speech, but also argue for the reconceptualization of communicative disorders within a cultural framework. Along with recent studies documenting cultural differences in visual perception, our auditory evidence challenges the common assumption of universality of basic mental processes and speaks to the domain generality of

  15. Pitch memory and exposure effects.

    Science.gov (United States)

    Ben-Haim, Moshe Shay; Eitan, Zohar; Chajut, Eran

    2014-02-01

    Recent studies indicate that the ability to represent absolute pitch values in long-term memory, long believed to be the possession of a small minority of trained musicians endowed with "absolute pitch," is in fact shared to some extent by a considerable proportion of the population. The current study examined whether this newly discovered ability affects aspects of music and auditory cognition, particularly pitch learning and evaluation. Our starting points are two well-established premises: (1) frequency of occurrence has an influence on the way we process stimuli; (2) in Western music, some pitches and musical keys are much more frequent than others. Based on these premises, we hypothesize that if absolute pitch values are indeed represented in long-term memory, pitch frequency of occurrence in music would significantly affect cognitive processes, in particular pitch learning and evaluation. Two experiments were designed to test this hypothesis in participants with no absolute pitch, most with little or no musical training. Experiment 1 demonstrated a faster response and a learning advantage for frequent pitches over infrequent pitches in an identification task. In Experiment 2, participants evaluated infrequent pitches as more pleasing than frequent pitches when presented in isolation. These results suggest that absolute pitch representation in memory may play a substantial, hitherto unacknowledged role in auditory (and specifically musical) cognition. PsycINFO Database Record (c) 2014 APA, all rights reserved.

  16. The impact of phonation mode and vocal technique on vocal fold closure in young females with normal voice quality.

    Science.gov (United States)

    De Bodt, Marc S; Clement, Gregory; Wuyts, Floris L; Borghs, Cindy; Van Lierde, Kristiane M

    2012-11-01

    Because voice quality depends substantially on vocal fold closure (VFC), voice therapists try to modify VFC by specific voice techniques or adjustments in phonation mode. This study demonstrates the impact of six different phonation modes on VFC in healthy subjects. For this study, 21 female subjects with normal voice quality were selected. The impact of different phonation modes and voice techniques was examined by fiberoptic laryngovideoendoscopy during different modes of phonation: habitual phonation, high pitch, low pitch, resonance on /m/, Coblenzer's "abspannen," and chant talk. The video recordings were judged by three experienced professionals (two Speech and Language Pathologist and one laryngologist) by means of a visual analog scale. Statistical analysis showed that only resonance on /m/ significantly improved VFC compared with habitual phonation. All other phonation modes and techniques, except low-pitched phonation, led to a significant worse closure in comparison with the closure at normal pitch. The glottic closure observed by low-pitched phonation was not significantly different than the closure at habitual pitch. Interrater agreement was moderate to very good, depending on the mode of phonation. The results of this study allow a better understanding of the impact of phonation mode and vocal therapy techniques on VFC in healthy subjects and give an indication about the impact of these methods to influence VFC. Copyright © 2012 The Voice Foundation. Published by Mosby, Inc. All rights reserved.

  17. Vocal Pitch Shift in Congenital Amusia (Pitch Deafness)

    Science.gov (United States)

    Hutchins, Sean; Peretz, Isabelle

    2013-01-01

    We tested whether congenital amusics, who exhibit pitch perception deficits, nevertheless adjust the pitch of their voice in response to a sudden pitch shift applied to vocal feedback. Nine amusics and matched controls imitated their own previously-recorded speech or singing, while the online feedback they received was shifted mid-utterance by 25…

  18. Norwegian Pitched Roof Defects

    Directory of Open Access Journals (Sweden)

    Lars Gullbrekken

    2016-06-01

    Full Text Available The building constructions investigated in this work are pitched wooden roofs with exterior vertical drainpipes and wooden load-bearing system. The aim of this research is to further investigate the building defects of pitched wooden roofs and obtain an overview of typical roof defects. The work involves an analysis of the building defect archive from the research institute SINTEF Building and Infrastructure. The findings from the SINTEF archive show that moisture is a dominant exposure factor, especially in roof constructions. In pitched wooden roofs, more than half of the defects are caused by deficiencies in design, materials, or workmanship, where these deficiencies allow moisture from precipitation or indoor moisture into the structure. Hence, it is important to increase the focus on robust and durable solutions to avoid defects both from exterior and interior moisture sources in pitched wooden roofs. Proper design of interior ventilation and vapour retarders seem to be the main ways to control entry from interior moisture sources into attic and roof spaces.

  19. Comparative analysis of low- and high-swirl confined flames and jets by proper orthogonal and dynamic mode decompositions

    Science.gov (United States)

    Markovich, D. M.; Abdurakipov, S. S.; Chikishev, L. M.; Dulin, V. M.; Hanjalić, K.

    2014-06-01

    Low-order coherent structures of non-reacting and combusting low- and high-swirl (swirl rates S = 0.41 and S = 1.0) jet flows in an open-ended cylindrical model combustor have been studied using the proper orthogonal decomposition (POD) and the dynamic mode decomposition (DMD) of high-repetition stereoscopic particle image velocimetry (PIV) velocity measurements. Lean methane-air mixture with the equivalence ratio of 0.6 was chosen for the reacting case as lean flames are generally less stable and more receptive to active control. The nonreacting and reacting flows at the same swirl rates exhibit qualitatively similar overall features characterized by highly turbulent annular jets enveloping the central retarding zone (for S = 0.41) or a recirculating bubble (for S = 1.0). At low swirl the dominant coherent structures appeared in the form of tilted ring vortices, evolving into helices as the swirl rate increases. The high-swirl flows are characterized by a pair of well-organized counter-rotating co-winding helical vortices originating in the inner and outer jet shear layers. Vortex cores were detected in both cases, but at low swirl it was less energetic and not associated with a distinct precession frequency. The core region of the low-swirl flame shows intermittent mild flow reversal without permanent central recirculation zone. The thermal expansion enhances the spreading of the reacting flow, especially at the high swirl number. Here the helices pitch is smaller and some neighbouring vortices merge into vortical sheets that act as shear shield confining the flame within the inner shear layer. Despite the significant effects of combustion on the time-averaged characteristics for the high-swirl, the dynamics of both flows were dominated by the global inviscid helical instability mode with a DMD detected conspicuous frequencies of 223 Hz for the nonreacting jet and 257 Hz for the flame.

  20. Nonlinear oscillations of TM-mode gyrotrons

    Science.gov (United States)

    Chang, Tsun-Hsu; Yao, Hsin-Yu; Su, Bo-Yuan; Huang, Wei-Chen; Wei, Bo-Yuan

    2017-12-01

    This study investigates the interaction between the relativistic electrons and the waves in cavities with fixed field profiles. Both the transverse electric (TE) and the transverse magnetic (TM) cavity modes are examined, including three first-axial modes, TE011, TM011, and TM111, and two zero-axial modes, TM010 and TM110. The first-axial modes have the same resonant frequency, so a direct comparison can be made. By sweeping the electron pitch factor (α) and the electron transit angle (Θ), the optimal converting efficiency of TM modes occurs at α = 1.5 and Θ = 1.5π, unlike the TE mode of α = 2.0 and Θ = 1.0π. The converting efficiencies of both the first-axial TM modes are much lower than that of TE011 mode. The starting currents of TM011 and TM111 modes are four times higher than that of TE011 mode, indicating that these two TM modes are very difficult to oscillate. This evidences that under the traditional operating conditions, the TM-mode gyrotrons are insignificant. However, the two unique, zero-axial TM modes have relatively high converting efficiency. The highest converting efficiency of TM110 is 27.4%, the same value as that of TE011 mode. The starting currents of TM110 mode and TE011 mode are at the same level. The results suggest that some TM-mode gyrotron oscillators are feasible and deserve further theoretical and experimental studies.

  1. Plasma channel undulator excited by high-order laser modes

    Science.gov (United States)

    Wang, Jingwei; Schroeder, Carl; Zepf, Matt; Rykovanov, Sergey

    2017-10-01

    The possibility of utilizing plasma undulators and plasma accelerators to produce compact and economical ultraviolet and X-ray radiation sources has attracted considerable interest for a few decades. This interest has been driven by the great potential to decrease the threshold for accessing such sources, which are now mainly provided by a very few dedicated large-scale synchrotron or free-electron laser (FEL) facilities. However, the typically broad radiation bandwidth of such plasma devices limits the source brightness and makes it difficult for the FEL instability to develop. Here, using multi-dimensional electromagnetic particle-in-cell simulations, we demonstrate that a plasma undulator generated by the beating of a mixture of high-order laser modes propagating inside a plasma channel, leads to a few percent radiation bandwidth. The strength of the undulator can reach unity, the period can be less than a millimeter, and the total number of undulator periods can be significantly increased by a phase locking technique based on the longitudinal density modulation. According to analytical estimates and simulations, in the fully beam loaded regime, the electron current in the undulator can reach 0.3 kA, making such an undulator a potential candidate towards a table-top FEL.

  2. Absolute pitch in Costa Rica: Distribution of pitch identification ability and implications for its genetic basis.

    Science.gov (United States)

    Chavarria-Soley, Gabriela

    2016-08-01

    Absolute pitch is the unusual ability to recognize a pitch without an external reference. The current view is that both environmental and genetic factors are involved in the acquisition of the trait. In the present study, 127 adult musicians were subjected to a musical tone identification test. Subjects were university music students and volunteers who responded to a newspaper article. The test consisted of the identification of 40 piano and 40 pure tones. Subjects were classified in three categories according to their pitch naming ability: absolute pitch (AP), high accuracy of tone identification (HA), and non-absolute pitch (non-AP). Both the percentage of correct responses and the mean absolute deviation showed a statistically significant variation between categories. A very clear pattern of higher accuracy for white than for black key notes was observed for the HA and the non-AP groups. Meanwhile, the AP group had an almost perfect pitch naming accuracy for both kinds of tones. Each category presented a very different pattern of deviation around the correct response. The age at the beginning of musical training did not differ between categories. The distribution of pitch identification ability in this study suggests a complex inheritance of the trait.

  3. The neurocognitive components of pitch processing: insights from absolute pitch.

    Science.gov (United States)

    Wilson, Sarah J; Lusher, Dean; Wan, Catherine Y; Dudgeon, Paul; Reutens, David C

    2009-03-01

    The natural variability of pitch naming ability in the population (known as absolute pitch or AP) provides an ideal method for investigating individual differences in pitch processing and auditory knowledge formation and representation. We have demonstrated the involvement of different cognitive processes in AP ability that reflects varying skill expertise in the presence of similar early age of onset of music tuition. These processes were related to different regions of brain activity, including those involved in pitch working memory (right prefrontal cortex) and the long-term representation of pitch (superior temporal gyrus). They reflected expertise through the use of context dependent pitch cues and the level of automaticity of pitch naming. They impart functional significance to structural asymmetry differences in the planum temporale of musicians and establish a neurobiological basis for an AP template. More generally, they indicate variability of knowledge representation in the presence of environmental fostering of early cognitive development that translates to differences in cognitive ability.

  4. The effect of mode scrambling on pulsed radar reflectometry applied to high shear devices

    NARCIS (Netherlands)

    Donne, A. J. H.; de M. Baar,; Cavazzana, R.

    1997-01-01

    In this article the effect of mode scrambling on the operation of pulsed radar reflectometers working in the ordinary polarization mode on devices with a high magnetic shear is studied. Mode scrambling occurs when the magnetic field changes considerably on length and/or time scales which are similar

  5. High-pitch coronary CT angiography at 70 kVp adopting a protocol of low injection speed and low volume of contrast medium

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Ruiqi; Liu, Xiao Fei; Zhao, Yu; Zhang, Liang [Dept. of Radiology, The First Affiliated Hospital of China Medical University, Shenyang (China); Tong, Jia Jie [Dept. of Radiology, Hebei General Hospital, Shijiazhuang(China)

    2017-09-15

    To evaluate the feasibility and image quality (IQ) of prospectively high-pitch coronary CT angiography (CCTA) with low contrast medium injection rate at 70 kVp. One hundred and four patients with suspected coronary artery disease (body mass index < 26 kg/m{sup 2}, sinus rhythm and heart rate < 70 beats/min) were prospectively enrolled and randomly divided into two groups. In group A and group B, 28 mL and 40 mL of 370 mgI/mL iodinated contrast media was administrated at a flow rate of 3.5 and 5 mL/s, respectively. CT values, noise, signal-to-noise ratio, contrast-to-noise ratio (CNR) of the proximal segments of coronary arteries and subjective IQ were evaluated. The CT values and noise in group A were significantly lower than those in group B (434–485 Hounsfield units [HU] vs. 772–851 HU, all p < 0.001; 17.8–22.3 vs. 23.3–26.4, all p < 0.005). The CNRs of the right coronary artery and left main artery showed no statistical difference between the two groups (42.1 ± 13.8 vs. 36.8 ± 16.0, p = 0.074; 38.7 ± 10.6 vs. 38.1 ± 17.0, p = 0.819). No statistical difference was observed between the two groups in IQ scores (3.04 ± 0.75 vs. 3.0 ± 0.79, p = 0.526) and diagnostic ratio (96.1% [50/52] vs. 94.2% [49/52], p = 0.647). Prospective high-pitch CCTA at 70 kVp with 28 mL of contrast media and injection rate of 3.5 mL/s could provide diagnostic IQ for normal-weight patients with heart rate of < 70 beats/min.

  6. Prosodic Transfer: From Chinese Lexical tone to English Pitch Accent

    Directory of Open Access Journals (Sweden)

    Marie Ploquin

    2013-01-01

    Full Text Available Chinese tones are associated with a syllable to convey meaning, English pitch accents are prominence markers associated with stressed syllables.  As both are created by pitch modulation, their pitch contours can be quite similar.  The experiment reported here examines whether native speakers of Chinese produce, when speaking English, the Chinese tone whose phonetic contour most closely matches the contour of the intended English pitch accent.  Six native speakers of Chinese recorded English and Chinese sentences, all including the segment [fan].  Results show that the subjects produced a Chinese tone 2 where a rising pitch accents was required and thus that speakers of Chinese rely on their lexical tones inventory to produce English prosody. The results obtained with falling pitch accents are much less conclusive partly because of the difficulty in measuring tone 3 due to the high level of creak that accompanies it.

  7. Adaptive slope compensation for high bandwidth digital current mode controller

    DEFF Research Database (Denmark)

    Taeed, Fazel; Nymand, Morten

    2015-01-01

    An adaptive slope compensation method for digital current mode control of dc-dc converters is proposed in this paper. The compensation slope is used for stabilizing the inner current loop in peak current mode control. In this method, the compensation slope is adapted with the variations...... in converter duty cycle. The adaptive slope compensation provides optimum controller operation in term of bandwidth over wide range of operating points. In this paper operation principle of the controller is discussed. The proposed controller is implemented in an FPGA to control a 100 W buck converter...

  8. Design of mode converters from TE circular om modes in circular waveguides to TE rectangular mo modes in rectangular waveguides for high power applications in the frequency range 1 to 30 GHz

    Science.gov (United States)

    Janzen, G.

    1984-07-01

    A mode converter for transitions from circular symmetric modes to rectangular waveguide modes and vice versa for high power applications in plasma heating experiments is described. The converter conserves the power of all circular symmetric modes emitted by a gyrotron and aligns the fields into linearly polarized modes required for effective plasma heating by electron cyclotron or by lower hybrid resonance absorption. It also allows a convenient combination of the power output of several klystrons and mode conversion into modes with low attenuation. Suitable combinations of waveguide diameter and number of sectors dividing (or combining) the power avoid the excitation of unwanted modes.

  9. Wind turbine pitch control using ICPSO-PID algorithm

    DEFF Research Database (Denmark)

    Xu, Chang; Tian, Qiangqiang; Shen, Wen Zhong

    2013-01-01

    For the traditional simplified first-order pitch-control system model, it is difficult to describe a real dynamic characteristic of a variable pitch action system, thus a complete high order mathematical model has to be developed for the pitch control of wind turbine generation (WTG). In the paper...... controller parameters quickly; and the feed-forward controller for wind speed can improve dynamics of a pitch-control system; additionally the power controller can allow a wind turbine to have a constant power output as a wind speed is over the rated one. Compared with a conventional PID, the controller...

  10. Nulling, Mode-Changing and Drifting Subpulses in the Highly ...

    Indian Academy of Sciences (India)

    Since January 2016, the Journal of Astrophysics and Astronomy has moved to Continuous Article Publishing (CAP) mode. This means that each accepted article is being published immediately online with DOI and article citation ID with starting page number 1. Articles are also visible in Web of Science immediately.

  11. Nanocrystalline core material for high-performance common mode inductors

    NARCIS (Netherlands)

    Roc'h, A.; Leferink, Frank Bernardus Johannes

    Modern power electronic semiconductors are switching very fast to reduce heat dissipation. Due to parasitic capacitances in the system, for instance, in a motor driven by an adjustable speed electrical power drive system, common mode currents are developed creating electromagnetic interference. The

  12. Pitch-verticality and pitch-size cross-modal interactions

    DEFF Research Database (Denmark)

    Bonetti, Leonardo; Costa, Marco

    2017-01-01

    Two studies were conducted on cross-modal matching between pitch and sound source localization on the vertical axis, and pitch and size. In the first study 100 Hz, 200 Hz, 600 Hz, and 800 Hz tones were emitted by a loudspeaker positioned 60 cm above or below to the participant’s ear level. Using...... a speeded classification task, 30 participants had to indicate the sound source, in 160 trials. Both reaction times and errors were analyzed. The results showed that in the congruent condition of high-pitched tones emitted from the upper loudspeaker, reaction times were significantly faster and the number...... of errors was significantly lower. Pitch is mapped on the vertical axis for sound localization. A main effect for sound source direction was also found. Tones coming from the upper loudspeaker were recognized faster and more accurately. Males were faster than females in identifying sound source direction...

  13. Pitch perception deficits in nonverbal learning disability.

    Science.gov (United States)

    Fernández-Prieto, I; Caprile, C; Tinoco-González, D; Ristol-Orriols, B; López-Sala, A; Póo-Argüelles, P; Pons, F; Navarra, J

    2016-12-01

    The nonverbal learning disability (NLD) is a neurological dysfunction that affects cognitive functions predominantly related to the right hemisphere such as spatial and abstract reasoning. Previous evidence in healthy adults suggests that acoustic pitch (i.e., the relative difference in frequency between sounds) is, under certain conditions, encoded in specific areas of the right hemisphere that also encode the spatial elevation of external objects (e.g., high vs. low position). Taking this evidence into account, we explored the perception of pitch in preadolescents and adolescents with NLD and in a group of healthy participants matched by age, gender, musical knowledge and handedness. Participants performed four speeded tests: a stimulus detection test and three perceptual categorization tests based on colour, spatial position and pitch. Results revealed that both groups were equally fast at detecting visual targets and categorizing visual stimuli according to their colour. In contrast, the NLD group showed slower responses than the control group when categorizing space (direction of a visual object) and pitch (direction of a change in sound frequency). This pattern of results suggests the presence of a subtle deficit at judging pitch in NLD along with the traditionally-described difficulties in spatial processing. Copyright © 2016. Published by Elsevier Ltd.

  14. Servo-elastic dynamics of a hydraulic actuator pitching a blade with large deflections

    DEFF Research Database (Denmark)

    Hansen, Morten Hartvig; Kallesøe, Bjarne Skovmose

    2007-01-01

    This paper deals with the servo-elastic dynamics of a hydraulic pitch actuator acting on a largely bend wind turbine blade. The compressibility of the oil and flexibility of the hoses introduce a dynamic mode in the pitch bearing degree of freedom. This mode may obtain negative damping if the pro......This paper deals with the servo-elastic dynamics of a hydraulic pitch actuator acting on a largely bend wind turbine blade. The compressibility of the oil and flexibility of the hoses introduce a dynamic mode in the pitch bearing degree of freedom. This mode may obtain negative damping...... if the proportional gain on the actuator position error is defined too large relative to the viscous forces in the hydraulic system and the total rotational inertia of the pitch bearing degree of freedom. A simple expression for the stability limit of this proportional gain is derived for tuning the gain based...

  15. Difficulties with pitch discrimination influences pitch memory performance: evidence from congenital amusia

    National Research Council Canada - National Science Library

    Jiang, Cunmei; Lim, Vanessa K; Wang, Hang; Hamm, Jeff P

    2013-01-01

    Music processing is influenced by pitch perception and memory. Additionally these features interact, with pitch memory performance decreasing as the perceived distance between two pitches decreases...

  16. The mental space of pitch height.

    Science.gov (United States)

    Rusconi, Elena; Kwan, Bonnie; Giordano, Bruno; Umiltà, Carlo; Butterworth, Brian

    2005-12-01

    Through stimulus-response compatibility we tested whether sound frequency (pitch height) elicits a mental spatial representation. Musically untrained and, mostly, trained participants were shown a stimulus-response compatibility effect (Spatial-Musical Association of Response Codes or SMARC effect). When response alternatives were either vertically or horizontally aligned, performance was better when the lower (or leftward) button had to be pressed in response to a low sound and the upper (or rightward) button had to be pressed in response to a high sound, even when pitch height was irrelevant to the task.

  17. Facial expression and vocal pitch height: Evidence of an intermodal association

    DEFF Research Database (Denmark)

    Huron, David; Dahl, Sofia; Johnson, Randolph

    2009-01-01

    Forty-four participants were asked to sing moderate, high, and low  pitches while their faces were photographed. In a two-alternative forced choice task,  independent judges selected the high-pitch faces as more friendly than the low-pitch  faces. When photographs were cropped to show only the ey...... eyebrow position and sung pitch—consistent with the role of eyebrows in signaling aggression and appeasement. Overall, the results are consistent with an inter-modal linkage between vocal and facial expressions....... region, judges still rated the high-pitch faces friendlier than the low-pitch faces. These results are consistent with prior research showing that vocal pitch height is used to signal aggression (low pitch) or appeasement (high pitch). An analysis of the facial features shows a strong correlation between...

  18. Dispersion and optical gradient force from high-order mode coupling between two hyperbolic metamaterial waveguides

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Guanghui, E-mail: gsnuwgh@163.com; Zhang, Weifeng; Lu, Jiahui; Zhao, Huijun

    2016-08-12

    We analytically study dispersion properties and optical gradient forces of different-order transverse magnetic (TM) modes in two coupled hyperbolic metamaterial waveguides (HMMWs). According to Maxwell's equations, we obtain the dispersion relation of symmetric and antisymmetric modes, and calculate optical gradient forces of different-order modes by using Maxwell stress tensor. Numerical results show that the dispersion properties are dependent on the filling ratio, and the optical gradient forces of high-order TM modes are larger than the fundamental mode when the gap between two HMMWs is very narrow, but they weaken much faster than the case of low-order TM modes with the gap width increasing. In addition, the effects of the dielectric surrounding of waveguides on the coupling effect and optical gradient force are clarified. These properties offer an avenue for various optomechanical applications in optical sensors and actuators. - Highlights: • The dependence of dispersion properties in hyperbolic metamaterials on the filling ratio is analyzed. • It is possible that the optical gradient forces of high-order modes are larger than the fundamental mode. • Optical gradient forces of high-order modes weaken much faster than the case of low-order modes. • The influence of the dielectric surrounding on the coupling effect and optical gradient force are clarified.

  19. Ultra-high Q whispering-gallery-mode bottle microresonators: properties and applications

    NARCIS (Netherlands)

    O'Shea, Danny; Junge, Christian; Nickel, Sebastian; Pöllinger, Michael; Rauschenbeutel, Arno; Kudryashov, Alexis V.; Paxton, Alan H.; Ilchenko, Vladimir S.

    2011-01-01

    Highly prolate-shaped whispering-gallery-mode "bottle microresonators" have recently attracted considerable attention due to their advantageous properties. We experimentally show that such resonators offer ultra-high quality factors, microscopic mode volumes, and near lossless in- and out-coupling

  20. Augmented Adaptive Control of a Wind Turbine in the Presence of Structural Modes

    Science.gov (United States)

    Frost, Susan A.; Balas, Mark J.; Wright, Alan D.

    2010-01-01

    Wind turbines operate in highly turbulent environments resulting in aerodynamic loads that can easily excite turbine structural modes, potentially causing component fatigue and failure. Two key technology drivers for turbine manufacturers are increasing turbine up time and reducing maintenance costs. Since the trend in wind turbine design is towards larger, more flexible turbines with lower frequency structural modes, manufacturers will want to develop methods to operate in the presence of these modes. Accurate models of the dynamic characteristics of new wind turbines are often not available due to the complexity and expense of the modeling task, making wind turbines ideally suited to adaptive control. In this paper, we develop theory for adaptive control with rejection of disturbances in the presence of modes that inhibit the controller. We use this method to design an adaptive collective pitch controller for a high-fidelity simulation of a utility-scale, variable-speed wind turbine operating in Region 3. The objective of the adaptive pitch controller is to regulate generator speed, accommodate wind gusts, and reduce the interference of certain structural modes in feedback. The control objective is accomplished by collectively pitching the turbine blades. The adaptive pitch controller for Region 3 is compared in simulations with a baseline classical Proportional Integrator (PI) collective pitch controller.

  1. Control of variable speed variable pitch wind turbine based on a disturbance observer

    Science.gov (United States)

    Ren, Haijun; Lei, Xin

    2017-11-01

    In this paper, a novel sliding mode controller based on disturbance observer (DOB) to optimize the efficiency of variable speed variable pitch (VSVP) wind turbine is developed and analyzed. Due to the highly nonlinearity of the VSVP system, the model is linearly processed to obtain the state space model of the system. Then, a conventional sliding mode controller is designed and a DOB is added to estimate wind speed. The proposed control strategy can successfully deal with the random nature of wind speed, the nonlinearity of VSVP system, the uncertainty of parameters and external disturbance. Via adding the observer to the sliding mode controller, it can greatly reduce the chattering produced by the sliding mode switching gain. The simulation results show that the proposed control system has the effectiveness and robustness.

  2. Lower extremity muscle activation during baseball pitching.

    Science.gov (United States)

    Campbell, Brian M; Stodden, David F; Nixon, Megan K

    2010-04-01

    The purpose of this study was to investigate muscle activation levels of select lower extremity muscles during the pitching motion. Bilateral surface electromyography data on 5 lower extremity muscles (biceps femoris, rectus femoris, gluteus maximus, vastus medialis, and gastrocnemius) were collected on 11 highly skilled baseball pitchers and compared with individual maximal voluntary isometric contraction (MVIC) data. The pitching motion was divided into 4 distinct phases: phase 1, initiation of pitching motion to maximum stride leg knee height; phase 2, maximum stride leg knee height to stride foot contact (SFC); phase 3, SFC to ball release; and phase 4, ball release to 0.5 seconds after ball release (follow-through). Results indicated that trail leg musculature elicited moderate to high activity levels during phases 2 and 3 (38-172% of MVIC). Muscle activity levels of the stride leg were moderate to high during phases 2-4 (23-170% of MVIC). These data indicate a high demand for lower extremity strength and endurance. Specifically, coaches should incorporate unilateral and bilateral lower extremity exercises for strength improvement or maintenance and to facilitate dynamic stabilization of the lower extremities during the pitching motion.

  3. Spiral model of pitch

    Science.gov (United States)

    Miller, James D.

    2003-10-01

    A spiral model of pitch interrelates tone chroma, tone height, equal temperament scales, and a cochlear map. Donkin suggested in 1870 that the pitch of tones could be well represented by an equiangular spiral. More recently, the cylindrical helix has been popular for representing tone chroma and tone height. Here it is shown that tone chroma, tone height, and cochlear position can be conveniently related to tone frequency via a planar spiral. For this ``equal-temperament spiral,'' (ET Spiral) tone chroma is conceived as a circular array with semitones at 30° intervals. The frequency of sound on the cent scale (re 16.351 Hz) is represented by the radius of the spiral defined by r=(1200/2π)θr, where θr is in radians. By these definitions, one revolution represents one octave, 1200 cents, 30° represents a semitone, the radius relates θ to cents in accordance with equal temperament (ET) tuning, and the arclength of the spiral matches the mapping of sound frequency to the basilar membrane. Thus, the ET Spiral gives tone chroma as θ, tone height as the cent scale, and the cochlear map as the arclength. The possible implications and directions for further work are discussed.

  4. Turbulence at the transition to the high density H-mode in Wendelstein 7-AS plasmas

    DEFF Research Database (Denmark)

    Basse, N.P.; Zoletnik, S.; Baumel, S.

    2003-01-01

    Recently a new improved confinement regime was found in the Wendelstein 7-AS (W7-AS) stellarator (Renner H. et al 1989 Plasma Phys. Control. Fusion 31 1579). The discovery of this high density high confinement mode (HDH-mode) was facilitated by the installation of divertor modules. In this paper......, measurements of short wavelength density fluctuations in the HDH-mode using collective scattering of infrared light are presented. These measurements will be contrasted to fluctuations during normal confinement operation (NC-mode). The autopower spectra of the measurements show a consistent increase...... of the fluctuation level associated with the transition from NC- to HDH-mode. Correlation calculations on a 20 mus timescale between magnetic and density fluctuations lead to the result that the fluctuations are correlated in NC- but not in HDH-mode. Finally, a comparative analysis between the enhanced D-alpha H...

  5. Non-linear interaction between high energy ions and MHD-modes

    Energy Technology Data Exchange (ETDEWEB)

    Bergkvist, Tommy

    2001-12-01

    When heating a fusion plasma with ICRE or NBI a non-Maxwellian distribution function with high energy ions is created. Ions which are in resonance with a MHD mode will interact with the electric field from the mode and in some circumstances energy will flow from the particles to the mode or opposite. A quasi-linear model for the interaction between high energy ions and a MHD mode has been developed. To solve the time evolution of the MHD mode a module has been implemented into the Monte Carlo code FIDO, which is used for calculating a 3-dimensional distribution function. The model has been tested for an internal kink mode during fishbone oscillations.

  6. High-speed dynamic-mode atomic force microscopy imaging of polymers: an adaptive multiloop-mode approach.

    Science.gov (United States)

    Ren, Juan; Zou, Qingze

    2017-01-01

    Adaptive multiloop-mode (AMLM) imaging to substantially increase (over an order of magnitude) the speed of tapping-mode (TM) imaging is tested and evaluated through imaging three largely different heterogeneous polymer samples in experiments. It has been demonstrated that AMLM imaging, through the combination of a suite of advanced control techniques, is promising to achieve high-speed dynamic-mode atomic force microscopy imaging. The performance, usability, and robustness of the AMLM in various imaging applications, however, is yet to be assessed. In this work, three benchmark polymer samples, including a PS-LDPE sample, an SBS sample, and a Celgard sample, differing in feature size and stiffness of two orders of magnitude, are imaged using the AMLM technique at high-speeds of 25 Hz and 20 Hz, respectively. The comparison of the images obtained to those obtained by using TM imaging at scan rates of 1 Hz and 2 Hz showed that the quality of the 25 Hz and 20 Hz AMLM imaging is at the same level of that of the 1 Hz TM imaging, while the tip-sample interaction force is substantially smaller than that of the 2 Hz TM imaging.

  7. High-Order Sliding Mode Control for DFIG-Based Wind Turbine Fault Ride-Through

    OpenAIRE

    Benbouzid, Mohamed; Beltran, Brice; Amirat, Yassine; Gang, Yao; Jingang, Han; Mangel, Hervé

    2013-01-01

    International audience; This paper deals with the Fault Ride-Through (FRT) capability assessment of a Doubly-Fed Induction Generator (DFIG)-based Wind Turbine (WT) using High-Order Sliding Mode (HOSM) control. Indeed, it has been recently suggested that sliding mode control is a solution of choice to the FRT problem. In this context, this paper proposes HOSM as an improved solution that handle the classical sliding mode chattering problem. Indeed, the main and attractive features of HOSMs are...

  8. Scalable mode division multiplexed transmission over a 10-km ring-core fiber using high-order orbital angular momentum modes.

    Science.gov (United States)

    Zhu, Guoxuan; Hu, Ziyang; Wu, Xiong; Du, Cheng; Luo, Wenyong; Chen, Yujie; Cai, Xinlun; Liu, Jie; Zhu, Jiangbo; Yu, Siyuan

    2018-01-22

    We propose and demonstrate a scalable mode division multiplexing scheme based on orbital angular momentum modes in ring core fibers. In this scheme, the high-order mode groups of a ring core fiber are sufficiently de-coupled by the large differential effective refractive index so that multiple-input multiple-output (MIMO) equalization is only used for crosstalk equalization within each mode group. We design and fabricate a graded-index ring core fiber that supports 5 mode groups with low inter-mode-group coupling, small intra-mode-group differential group delay, and small group velocity dispersion slope over the C-band for the high-order mode groups. We implement a two-dimensional wavelength- and mode-division multiplexed transmission experiment involving 10 wavelengths and 2 mode groups each with 4 OAM modes, transmitting 32 GBaud Nyquist QPSK signals over all 80 channels. An aggregate capacity of 5.12 Tb/s and an overall spectral efficiency of 9 bit/s/Hz over 10 km are realized, only using modular 4x4 MIMO processing with 15 taps to recover signals from the intra-mode-group mode coupling. Given the fixed number of modes in each mode group and the low inter-mode-group coupling in ring core fibres, our scheme strikes a balance in the trade-off between system capacity and digital signal processing complexity, and therefore has good potential for capacity upscaling at an expense of only modularly increasing the number of mode-groups with fixed-size (4x4) MIMO blocks.

  9. Pitch height modulates visual and haptic bisection performance in musicians

    Directory of Open Access Journals (Sweden)

    Carlotta eLega

    2014-04-01

    Full Text Available Consistent evidence suggests that pitch height may be represented in a spatial format, having both a vertical and an horizontal representation. The spatial representation of pitch height results into response compatibility effects for which high pitch tones are preferentially associated to up-right responses, and low pitch tones are preferentially associated to down-left responses (i.e., the SMARC effect, with the strength of these associations depending on individuals’ musical skills. In this study we investigated whether listening to tones of different pitch affects the representation of external space, as assessed in a visual and haptic line bisection paradigm, in musicians and non musicians. Low and high pitch tones affected the bisection performance in musicians differently, both when pitch was relevant and irrelevant for the task, and in both the visual and the haptic modality. No effect of pitch height was observed on the bisection performance of non musicians. Moreover, our data also show that musicians present a (supramodal rightward bisection bias in both the visual and the haptic modality, extending previous findings limited to the visual modality, and consistent with the idea that intense practice with musical notation and bimanual instrument training affects hemispheric lateralization.

  10. Auditory deficits in amusia extend beyond poor pitch perception.

    Science.gov (United States)

    Whiteford, Kelly L; Oxenham, Andrew J

    2017-05-01

    Congenital amusia is a music perception disorder believed to reflect a deficit in fine-grained pitch perception and/or short-term or working memory for pitch. Because most measures of pitch perception include memory and segmentation components, it has been difficult to determine the true extent of pitch processing deficits in amusia. It is also unclear whether pitch deficits persist at frequencies beyond the range of musical pitch. To address these questions, experiments were conducted with amusics and matched controls, manipulating both the stimuli and the task demands. First, we assessed pitch discrimination at low (500Hz and 2000Hz) and high (8000Hz) frequencies using a three-interval forced-choice task. Amusics exhibited deficits even at the highest frequency, which lies beyond the existence region of musical pitch. Next, we assessed the extent to which frequency coding deficits persist in one- and two-interval frequency-modulation (FM) and amplitude-modulation (AM) detection tasks at 500Hz at slow (fm=4Hz) and fast (fm=20Hz) modulation rates. Amusics still exhibited deficits in one-interval FM detection tasks that should not involve memory or segmentation. Surprisingly, amusics were also impaired on AM detection, which should not involve pitch processing. Finally, direct comparisons between the detection of continuous and discrete FM demonstrated that amusics suffer deficits in both coding and segmenting pitch information. Our results reveal auditory deficits in amusia extending beyond pitch perception that are subtle when controlling for memory and segmentation, and are likely exacerbated in more complex contexts such as musical listening. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Interaural pitch perception difference: dependence upon internal and external factors.

    Science.gov (United States)

    Mürbe, D; Kevanishvili, Z; Kuhlisch, E; Hofmann, G; Zahnert, Th

    2007-03-01

    Tone pulses were presented consecutively to one and the other ear in normally hearing musicians. The frequency of pulses in one, reference ear was fixed. That in the other, test ear varied to achieve the same pitch of tones in both ears. The frequency deviation of the test tone from the reference one was judged as the interaural pitch perception difference, IPPD. No dissimilarities in IPPDs were found between females and males. On the other hand, in both genders the IPPD scores were greater at higher than at medium and, especially, at lower tone frequencies, 2000, 1000, and 500 Hz, respectively. Also, the IPPDs displayed greater values when the reference tone was administered to the left ear, while the right ear served for the application of the test tone, LrRt, than when the reference tone was delivered to the right ear, while the test tone was applied to the left ear, RrLt. The IPPD differences under LrRt and RrLt stimulus presentations modes were prominent just at higher than at medium and, especially, at lower tone frequencies. The results are interpreted proceeding from the peculiar coding of low- and high-frequency acoustic information into brain auditory structures. Correspondingly, the IPPD is considered to be a consequence of central neural rather than of peripheral receptor events.

  12. High temperature sensing using higher-order-mode rejected sapphire-crystal fiber gratings

    Science.gov (United States)

    Zhan, Chun; Kim, Jae Hun; Lee, Jon; Yin, Stuart; Ruffin, Paul; Luo, Claire

    2007-09-01

    In this paper, we report the fabrication of higher-order-mode rejected fiber Bragg gratings (FBGs) in sapphire crystal fiber using infrared (IR) femtosecond laser illumination. The grating is tested in high temperature furnace up to 1600 degree Celsius. As sapphire fiber is only available as highly multimode fiber, a scheme to filter out higher order modes in favor for the fundamental mode is theoretically evaluated and experimentally demonstrated. The approach is to use an ultra thin sapphire crystal fiber (60 micron in diameter) to decrease the number of modes. The small diameter fiber also enables bending the fiber to certain radius which is carefully chosen to provide low loss for the fundamental mode LP01 and high loss for the other high-order modes. After bending, less-than-2-nm resonant peak bandwidth is achieved. The grating spectrum is improved, and higher resolution sensing measurement can be achieved. This mode filtering method is very easy to implement. Furthermore, the sapphire fiber is sealed with hi-purity alumina ceramic cement inside a flexible high temperature titanium tube, and the highly flexible titanium tube offers a robust packaging to sapphire fiber. Our high temperature sapphire grating sensor is very promising in extremely high temperature sensing application.

  13. High-pitch, low-voltage and low-iodine-concentration CT angiography of aorta: assessment of image quality and radiation dose with iterative reconstruction.

    Directory of Open Access Journals (Sweden)

    Yanguang Shen

    Full Text Available To assess the image quality of aorta obtained by dual-source computed tomography angiography (DSCTA, performed with high pitch, low tube voltage, and low iodine concentration contrast medium (CM with images reconstructed using iterative reconstruction (IR.One hundred patients randomly allocated to receive one of two types of CM underwent DSCTA with the electrocardiogram-triggered Flash protocol. In the low-iodine group, 50 patients received CM containing 270 mg I/mL and were scanned at low tube voltage (100 kVp. In the high-iodine CM group, 50 patients received CM containing 370 mg I/mL and were scanned at the tube voltage (120 kVp. The filtered back projection (FBP algorithm was used for reconstruction in both groups. In addition, the IR algorithm was used in the low-iodine group. Image quality of the aorta was analyzed subjectively by a 3-point grading scale and objectively by measuring the CT attenuation in terms of the signal- and contrast-to-noise ratios (SNR and CNR, respectively. Radiation and CM doses were compared.The CT attenuation, subjective image quality assessment, SNR, and CNR of various aortic regions of interest did not differ significantly between two groups. In the low-iodine group, images reconstructed by FBP and IR demonstrated significant differences in image noise, SNR, and CNR (p<0.05. The low-iodine group resulted in 34.3% less radiation (4.4 ± 0.5 mSv than the high-iodine group (6.7 ± 0.6 mSv, and 27.3% less iodine weight (20.36 ± 2.65 g than the high-iodine group (28 ± 1.98 g. Observers exhibited excellent agreement on the aortic image quality scores (κ = 0.904.CT images of aorta could be obtained within 2 s by using a DSCT Flash protocol with low tube voltage, IR, and low-iodine-concentration CM. Appropriate contrast enhancement was achieved while maintaining good image quality and decreasing the radiation and iodine doses.

  14. Investigating Enhancement Mode Gallium Nitride Power FETs in High Voltage, High Frequency Soft Switching Converters

    DEFF Research Database (Denmark)

    Nour, Yasser; Knott, Arnold; Jørgensen, Ivan Harald Holger

    2016-01-01

    of using enhancement mode gallium nitride switches to form a 50V quasi-square-wave zero-voltage-switching buck converter running at 2-6 MHz under full load. The designed converter achieved 83% efficiency converting 50V input voltage to 12.2V at 9W load.......An increased attention has been detected to develop smaller and lighter high voltage power converters in the range of 50V to 400V domain. The main applications for these converters are mainly focused for Power over Ethernet (PoE), LED lighting and AC adapters. This work will discuss a study...

  15. Investigating Enhancement Mode Gallium Nitride Power FETs in High Voltage, High Frequency Soft Switching Converters

    DEFF Research Database (Denmark)

    Nour, Yasser; Knott, Arnold; Jørgensen, Ivan Harald Holger

    2016-01-01

    An increased attention has been detected to develop smaller and lighter high voltage power converters in the range of 50V to 400V domain. The main applications for these converters are mainly focused for Power over Ethernet (PoE), LED lighting and AC adapters. This work will discuss a study of us...... of using enhancement mode gallium nitride switches to form a 50V quasi-square-wave zero-voltage-switching buck converter running at 2-6 MHz under full load. The designed converter achieved 83% efficiency converting 50V input voltage to 12.2V at 9W load....

  16. West African languages enrich the frequency code: Multi-functional pitch and multi-dimensional prosody in Ikaan polar questions

    Directory of Open Access Journals (Sweden)

    Sophie Salffner

    2017-06-01

    Full Text Available Cross-linguistically, statements tend to be pronounced with low or falling pitch and questions with high or rising pitch, a form–meaning pairing which has been attributed to the frequency code (Ohala, 1984. In many West African languages, however, questions are marked with a ‘lax’ prosody comprising falling intonation, low tones, lengthening, breathy termination, and open vowels (Rialland, 2007. This paper presents prosody findings from Ikaan (Niger-Congo; ISO 639-3: kcf and proposes a re-analysis of the West African lax question prosody to integrate it with the frequency code model. The paper shows that the pragmatic functions of statement and polar question are expressed prosodically in Ikaan. Audio recordings of statements and morphosyntactically identical polar questions by six speakers were annotated segmentally, tonally, and for the presence of prosodic question markers. Speakers mark questions by using higher onset pitch, wider drops to final low tones, final breathy voice and voicelessness, final vowel lengthening, vowel insertion, and increased intensity. Breathiness may further contrast with creaky voice and glottal stops in statements. Phonation mode, and the accompanying vowel lengthening and insertion, are argued to indicate friendliness and appeals for collaboration, linking phonation mode to similar functions of higher pitch in the frequency code.

  17. The role of femininity and averageness of voice pitch in aesthetic judgments of women's voices.

    Science.gov (United States)

    Feinberg, David R; DeBruine, Lisa M; Jones, Benedict C; Perrett, David I

    2008-01-01

    Although averageness is preferred in auditory stimuli (eg music) and non-face objects (eg wristwatches), exaggerated feminine characteristics are preferred to averageness in female faces. To establish whether or not men prefer femininity in female voices to average characteristics, we conducted a correlational study (study 1) to assess the relationship between voice pitch and attractiveness ratings. We found a positive linear relationship between voice pitch and attractiveness ratings. In study 2 we manipulated pitch in women's voices with low (lower than average), average, and high (higher than average) starting pitches and gauged men's preferences. Men preferred women's voices with raised pitch for all levels of starting pitch. These findings suggest that men prefer high voice pitch to average voice pitch in women's voices.

  18. Simple Correctors for Elimination of High-Order Modes in Corrugated Waveguide Transmission Lines.

    Science.gov (United States)

    Kowalski, Elizabeth J; Shapiro, Michael A; Temkin, Richard J

    2014-01-01

    When using overmoded corrugated waveguide transmission lines for high power applications, it is necessary to control the mode content of the system. Ideally, overmoded corrugated transmission lines operate in the fundamental HE11 mode and provide low losses for long distances. Unwanted higher order modes (HOMs), particularly LP11 and HE12, are often excited in the experimental systems due to practical misalignments in the transmission line system. This paper discusses how the unwanted modes propagate along with the fundamental mode in the transmission line system by formulating an equation that relates the center of power offset and angle of propagation of a beam (for the HE11 and LP11 modes) or the waist size and phase front radius of curvature of a beam (for the HE11 and HE12 modes). By introducing two miter bend correctors into the transmission system-miter bends that have slightly angled or ellipsoidal mirrors-the HOMs can be precisely manipulated in the system. This technique can be used to eliminate small quantities of unwanted modes, thereby creating a nearly pure fundamental mode beam with minimal losses. Examples of these applications are calculated and show the theoretical conversion of up to 10% HOM content into the fundamental HE11 mode with minimal losses.

  19. The Influence of Voice Pitch on the Evaluation of a Social Robot Receptionist

    NARCIS (Netherlands)

    Niculescu, A.I.; van Dijk, Elisabeth M.A.G.; Nijholt, Antinus; See, Swee Lan

    2011-01-01

    In this paper we present an experiment addressing the effect of voice pitch on the evaluation of a social robot receptionist. Twenty eight test participants interacted with two “female‿ robot characters: one with a high-pitched, exuberant voice, the other with a low-pitched, calm voice. Our results

  20. Radial index of Laguerre-Gaussian modes in high-order-harmonic generation

    Science.gov (United States)

    Géneaux, Romain; Chappuis, Céline; Auguste, Thierry; Beaulieu, Samuel; Gorman, Timothy T.; Lepetit, Fabien; DiMauro, Louis F.; Ruchon, Thierry

    2017-05-01

    High-order-harmonic generation (HHG) is a tabletop and tunable source of extreme ultraviolet (XUV) light. Its flexibility was lately evidenced by the production of Laguerre-Gaussian (LG) modes in the XUV with a known azimuthal index. Here we investigate the role of the radial index of LG modes in HHG. We show both numerically and experimentally that the mode content of the emitted XUV radiation can be tuned by controlling the weight of the different quantum trajectories involved in the process. The appearance of high-order radial modes is finally linked to the atomic dipole phase of HHG. These results extend the capabilities of shaping the spatial mode of ultrashort XUV pulses of light.

  1. Acceleration of FDTD mode solver by high-performance computing techniques.

    Science.gov (United States)

    Han, Lin; Xi, Yanping; Huang, Wei-Ping

    2010-06-21

    A two-dimensional (2D) compact finite-difference time-domain (FDTD) mode solver is developed based on wave equation formalism in combination with the matrix pencil method (MPM). The method is validated for calculation of both real guided and complex leaky modes of typical optical waveguides against the bench-mark finite-difference (FD) eigen mode solver. By taking advantage of the inherent parallel nature of the FDTD algorithm, the mode solver is implemented on graphics processing units (GPUs) using the compute unified device architecture (CUDA). It is demonstrated that the high-performance computing technique leads to significant acceleration of the FDTD mode solver with more than 30 times improvement in computational efficiency in comparison with the conventional FDTD mode solver running on CPU of a standard desktop computer. The computational efficiency of the accelerated FDTD method is in the same order of magnitude of the standard finite-difference eigen mode solver and yet require much less memory (e.g., less than 10%). Therefore, the new method may serve as an efficient, accurate and robust tool for mode calculation of optical waveguides even when the conventional eigen value mode solvers are no longer applicable due to memory limitation.

  2. Very High Frequency Switch-Mode Power Supplies

    DEFF Research Database (Denmark)

    Madsen, Mickey Pierre

    The importance of technology and electronics in our daily life is constantly increasing. At the same time portability and energy efficiency are currently some of the hottest topics. This creates a huge need for power converters in a compact form factor and with high efficiency, which can supply...... band gap semiconductors and integrated power supplies. Afterwards a wide range of topologies suited for operation at very high frequencies is investigated and the most promising ones are tested experimentally. Through a comparison of these topologies the class DE inverter is found to be superior...... to the other alternatives, at least for converters with hundreds of volts as input and a few tens of watts output power. A class DE inverter does however require a high side gate drive, which have never been presented before for these frequencies and voltages. This thesis presents the worlds first high side...

  3. Mode profiling of optical fibers at high laser powers

    DEFF Research Database (Denmark)

    Nielsen, Peter Carøe; Pedersen, David Bue; Simonsen, R.B.

    2008-01-01

    is obtained. Choosing a highly reflective rod material and a sufficiently high rotation speed, these measurements can be done with high laser powers, without any additional optical elements between the fiber and analyzer. The performance of the analyzer was evaluated by coupling laser light into different......This paper describes the development of a measuring equipment capable of analysing the beam profile at high optical powers emitted by delivery fibers used in manufacturing processes. Together with the optical delivery system, the output beam quality from the delivery fiber and the shape...... of the focused spot can be determined. The analyser is based on the principle of a rotating wire being swept though the laser beam, while the reflected signal is recorded [1]. By changing the incident angle of the rotating rod from 0° to 360° in relation to the fiber, the full profile of the laser beam...

  4. High-pitch computed tomography of the lung in pediatric patients. An intraindividual comparison of image quality and radiation dose to conventional 64-MDCT

    Energy Technology Data Exchange (ETDEWEB)

    Tsiflikas, I.; Thomas, C.; Ketelsen, D.; Claussen, C.D.; Schaefer, J.F. [University Hospital of Tuebingen (Germany). Diagnostic and Interventional Radiology; Seitz, G.; Warmann, S. [University Hospital of Tuebingen (Germany). Pediatric Surgery

    2014-06-15

    Purpose: The aim of this study was to investigate frequencies of typical artifacts in low-dose pediatric lung examinations using high-pitch computed tomography (HPCT) compared to MDCT, and to estimate the effective radiation dose (E{sub eff}). Materials and Methods: Institutional review board approval for this retrospective study was obtained. 35 patients (17 boys, 18 girls; mean age 112 ± 69 months) were included and underwent MDCT and follow-up scan by HPCT or vice versa (mean follow-up time 87 days), using the same tube voltage and current. The total artifact score (0-8) was defined as the sum of artifacts arising from movement, breathing or pulsation of the heart or pulmonary vessels (0 - no; 1 - moderate; 2 - severe artifacts). E{sub eff} was estimated according to the European Guidelines on Quality Criteria for Multislice Computed Tomography. The Mann-Whitney U test was used to analyze differences between the patient groups. The Spearman's rank correlation coefficient was used for correlation of ordinal variables. Results: The scan time was significantly lower for HPCT compared to MDCT (0.72 ± 0.13 s vs. 3.65 ± 0.81s; p < 0.0001). In 28 of 35 (80 %) HPCT examinations no artifacts were visible, whereas in MDCT artifacts occurred in all examinations. The frequency of pulsation artifacts and breathing artifacts was higher in MDCT compared to HPCT (100% vs. 17% and 31% vs. 6%). The total artifact score significantly correlated with the patient's age in MDCT (r=-0.42; p=0.01), but not in HPCT (r=-0.32; p=0.07). The estimated E{sub eff} was significantly lower in HPCT than in MDCT (1.29±0.31 vs. 1.47±0.37 mSv; p < 0.0001). Conclusion: Our study indicates that the use of HPCT has advantages for pediatric lung imaging with a reduction of breathing and pulsation artifacts. Moreover, the estimated E{sub eff} was lower. In addition, examinations can be performed without sedation or breath-hold without losing image quality. (orig.)

  5. Equations of motion for a rotor blade, including gravity, pitch action and rotor speed variations

    DEFF Research Database (Denmark)

    Kallesøe, Bjarne Skovmose

    2007-01-01

    This paper extends Hodges-Dowell's partial differential equations of blade motion, by including the effects from gravity, pitch action and varying rotor speed. New equations describing the pitch action and rotor speeds are also derived. The physical interpretation of the individual terms...... in the equations is discussed. The partial differential equations of motion are approximated by ordinary differential equations of motion using an assumed mode method. The ordinary differential equations are used to simulate a sudden pitch change of a rotating blade. This work is a part of a project on pitch blade...

  6. Effect of magnetic bending on the EBT high-frequency modes

    Energy Technology Data Exchange (ETDEWEB)

    El-Nadi, A.M.; Hiroe, S.; Whitson, J.C.; Hassen, H.F.; Kirolous, H.A.

    1986-02-01

    The high-frequency stability of the ELMO Bumpy Torus (EBT) device is studied when the wave vector has a finite component along the magnetic field lines. Unstable modes exist for any finite hot electron density. 9 refs., 1 fig.

  7. Finite-Bandwidth Resonances of High-Order Axial Modes (HOAM) in a Gyrotron Cavity

    OpenAIRE

    Sabchevski, Svilen; IDEHARA, Toshitaka

    2014-01-01

    Finite-bandwidth resonances of high-order axial modes (HOAM) in an open gyrotron cavity are studied numerically using the GYROSIM problem-oriented software package for modelling, simulation and computer-aided design (CAD) of gyrotron tubes.

  8. Robustness versus thermal effects of single-mode operation of vertical-cavity surface-emitting lasers with engineered leakage of high-order transverse optical modes

    Science.gov (United States)

    Kalosha, V. P.; Shchukin, V. A.; Ledentsov, N. N.; Kropp, J.-R.; Ledentsov, N. N.

    2017-02-01

    Design of the oxide-confined vertical cavity surface emitting laser (VCSEL) with enhanced engineered lateral leakage of high-order transverse optical modes is studied by three-dimensional optical modeling to evaluate the robustness of the leakage selection approach with respect to thermal effects. Both Joule heat and heat generated by the free carrier absorption of the optical mode in the doped semiconductor layers and their impact on the refractive index profile are considered. We show that for typical regimes of the VCSEL design and operation absorption-induced heat exceeds by several times the Joule heat while the shape of the generated heated domains strongly differ. Modeling shows that well defined spectral separation between the transverse optical modes persists upon increase in injection current. Further, upon increase in current the lateral extension of the fundamental mode decreases and the mode shrinks towards the center of the VCSEL structure thus reducing the lateral leakage and increasing the mode lifetime, whereas similar effect for high-order transverse modes is much weaker. Thus the preferred conditions for the lasing of the fundamental mode persist and even improve upon current increase. At high currents the fundamental mode becomes favorable at all aperture diameters, also for those where the cold cavity approximation predicts preference for the excited mode lasing.

  9. High-sensitivity imaging with lateral resonance mode atomic force microscopy.

    Science.gov (United States)

    Ding, Ren-Feng; Yang, Chih-Wen; Huang, Kuang-Yuh; Hwang, Ing-Shouh

    2016-11-03

    In the operation of a dynamic mode atomic force microscope, a micro-fabricated rectangular cantilever is typically oscillated at or near its mechanical resonance frequency. Lateral bending resonances of cantilevers are rarely used because the resonances are not expected to be detected by the beam-deflection method. In this work, we found that micro-cantilevers with a large tip produced an out-of-plane displacement in lateral resonance (LR), which could be detected with the beam-deflection method. Finite-element analysis indicated that the presence of a large tip is the major source of the out-of-plane coupling for the LR. We also imaged a heterogeneous sample by operating a cantilever in LR, torsional resonance, and tapping modes. LR mode yielded a small deformation and noise level in the height maps as well as a high contrast and small noise level in the phase maps. LR mode also had a resonance frequency that was orders of magnitude higher than that of tapping mode. Operation with LR mode may have the benefits of high-speed scanning, high-sensitivity imaging, and mapping of in-plane mechanical properties of the sample surface. In general, LR mode may become a powerful new atomic force microscopy technique for characterizing sample materials.

  10. Ultra-high Q whispering-gallery-mode bottle microresonators: properties and applications

    CERN Document Server

    O'Shea, D; Nickel, S; Poellinger, M; Rauschenbeutel, A; 10.1117/12.876790

    2011-01-01

    Highly prolate-shaped whispering-gallery-mode "bottle microresonators" have recently attracted considerable attention due to their advantageous properties. We experimentally show that such resonators offer ultra-high quality factors, microscopic mode volumes, and near lossless in- and out-coupling of light using ultra-thin optical fibers. Additionally, bottle microresonators have a simple and customizable mode structure. This enables full tunability using mechanical strain and simultaneous coupling of two ultra-thin coupling fibers in an add-drop configuration. We present two applications based on these characteristics: In a cavity quantum electrodynamics experiment, we actively stabilize the frequency of the bottle microresonator to an atomic transition and operate it in an ultra-high vacuum environment in order to couple single laser-cooled atoms to the resonator mode. In a second experiment, we show that the bottle microresonator can be used as a low-loss, narrow-band add-drop filter. Using the Kerr effect...

  11. Integrated Very High Frequency Switch Mode Power Supplies: Design Considerations

    DEFF Research Database (Denmark)

    Hertel, Jens Christian; Nour, Yasser; Knott, Arnold

    2017-01-01

    This paper presents a power supply using an increased switching frequency to minimize the size of energy storing components, thereby addressing the demands for increased power densities in power supplies. 100 MHz and higher switching frequencies have been used in resonant power converters, which...... simulations. The required spiral inductors was modeled, and simulations show Q values of as high as 14 at a switching frequency of 250 MHz. Simulations of the converter show an efficiency of 55 % with a self oscillating gate drive. However the modeled inductor was not adequate for operating with the self...

  12. Nonlinear resonances of three modes in a high-T{sub c} superconducting magnetic levitation system

    Energy Technology Data Exchange (ETDEWEB)

    Sasaki, Masahiko, E-mail: galian@z2.keio.jp; Sakaguchi, Ryunosuke; Sugiura, Toshihiko, E-mail: sugiura@mach.keio.ac.jp

    2013-11-15

    Highlights: •We studied two nonlinear vibrations of a levitated beam supported by superconductors. •One of the vibrations is combination resonance of the 1st mode and the 3rd mode. •The other vibration is autoparametric resonance of the 2nd mode. •When the amplitude of the 2nd mode is small, the combination resonance is suppressed. •Otherwise, the two resonances can be resonated simultaneously. -- Abstract: In a high-T{sub c} superconducting magnetic levitation system, an object can levitate without control and contact. So it is expected to be applied to magnetically levitated transportation. To use it safely, lightening the levitated object is necessary. But this reduces the bending stiffness of the object. Besides, the system has nonlinearity. Therefore nonlinear elastic vibration can occur. This study focused on how plural nonlinear elastic vibrations of the 1st, 2nd and 3rd modes simultaneously occur. Our numerical calculation and experiment found out that the three modes simultaneously resonate when the amplitude of the 2nd mode is large enough whereas only the 2nd mode resonates when it is small.

  13. Fast, High Resolution, and Wide Modulus Range Nanomechanical Mapping with Bimodal Tapping Mode.

    Science.gov (United States)

    Kocun, Marta; Labuda, Aleksander; Meinhold, Waiman; Revenko, Irène; Proksch, Roger

    2017-10-24

    Tapping mode atomic force microscopy (AFM), also known as amplitude modulated (AM) or AC mode, is a proven, reliable, and gentle imaging mode with widespread applications. Over the several decades that tapping mode has been in use, quantification of tip-sample mechanical properties such as stiffness has remained elusive. Bimodal tapping mode keeps the advantages of single-frequency tapping mode while extending the technique by driving and measuring an additional resonant mode of the cantilever. The simultaneously measured observables of this additional resonance provide the additional information necessary to extract quantitative nanomechanical information about the tip-sample mechanics. Specifically, driving the higher cantilever resonance in a frequency modulated (FM) mode allows direct measurement of the tip-sample interaction stiffness and, with appropriate modeling, the set point-independent local elastic modulus. Here we discuss the advantages of bimodal tapping, coined AM-FM imaging, for modulus mapping. Results are presented for samples over a wide modulus range, from a compliant gel (∼100 MPa) to stiff materials (∼100 GPa), with the same type of cantilever. We also show high-resolution (subnanometer) stiffness mapping of individual molecules in semicrystalline polymers and of DNA in fluid. Combined with the ability to remain quantitative even at line scan rates of nearly 40 Hz, the results demonstrate the versatility of AM-FM imaging for nanomechanical characterization in a wide range of applications.

  14. Modeling of Breathy Voice Quality Using Pitch-strength Estimates.

    Science.gov (United States)

    Eddins, David A; Anand, Supraja; Camacho, Arturo; Shrivastav, Rahul

    2016-11-01

    The characteristic voice quality of a speaker conveys important linguistic, paralinguistic, and vocal health-related information. Pitch strength refers to the salience of pitch sensation in a sound and was recently reported to be strongly correlated with the magnitude of perceived breathiness based on a small number of voice stimuli. The current study examined the relationship between perceptual judgments of breathiness and computational estimates of pitch strength based on the Aud-SWIPE (P-NP) algorithm for a large number of voice stimuli (330 synthetic and 57 natural). Similar to the earlier study, the current results confirm a strong relationship between estimated pitch strength and listener judgments of breathiness such that low pitch-strength values are associated with voices that have high perceived breathiness. Based on this result, a model was developed for the perception of breathy voice quality using a pitch-strength estimator. Regression functions derived between the pitch-strength estimates and perceptual judgments of breathiness obtained from matching task revealed a linear relationship for a subset of the natural stimuli. We then used this function to obtain predicted breathiness values for the synthetic and the remaining natural stimuli. Predicted breathiness values from our model were highly correlated with the perceptual data for both types of stimuli. Systematic differences between the breathiness of natural and synthetic stimuli are discussed. Copyright © 2016 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

  15. Kinematics and kinetics of elite windmill softball pitching.

    Science.gov (United States)

    Werner, Sherry L; Jones, Deryk G; Guido, John A; Brunet, Michael E

    2006-04-01

    A significant number of time-loss injuries to the upper extremity in elite windmill softball pitchers has been documented. The number of outings and pitches thrown in 1 week for a softball pitcher is typically far in excess of those seen in baseball pitchers. Shoulder stress in professional baseball pitching has been reported to be high and has been linked to pitching injuries. Shoulder distraction has not been studied in an elite softball pitching population. The stresses on the throwing shoulder of elite windmill pitchers are similar to those found for professional baseball pitchers. Descriptive laboratory study. Three-dimensional, high-speed (120 Hz) video data were collected on rise balls from 24 elite softball pitchers during the 1996 Olympic Games. Kinematic parameters related to pitching mechanics and resultant kinetics on the throwing shoulder were calculated. Multiple linear regression analysis was used to relate shoulder stress and pitching mechanics. Shoulder distraction stress averaged 80% of body weight for the Olympic pitchers. Sixty-nine percent of the variability in shoulder distraction can be explained by a combination of 7 parameters related to pitching mechanics. Excessive distraction stress at the throwing shoulder is similar to that found in baseball pitchers, which suggests that windmill softball pitchers are at risk for overuse injuries. Normative information regarding upper extremity kinematics and kinetics for elite softball pitchers has been established.

  16. Repetition suppression in auditory-motor regions to pitch and temporal structure in music.

    Science.gov (United States)

    Brown, Rachel M; Chen, Joyce L; Hollinger, Avrum; Penhune, Virginia B; Palmer, Caroline; Zatorre, Robert J

    2013-02-01

    Music performance requires control of two sequential structures: the ordering of pitches and the temporal intervals between successive pitches. Whether pitch and temporal structures are processed as separate or integrated features remains unclear. A repetition suppression paradigm compared neural and behavioral correlates of mapping pitch sequences and temporal sequences to motor movements in music performance. Fourteen pianists listened to and performed novel melodies on an MR-compatible piano keyboard during fMRI scanning. The pitch or temporal patterns in the melodies either changed or repeated (remained the same) across consecutive trials. We expected decreased neural response to the patterns (pitch or temporal) that repeated across trials relative to patterns that changed. Pitch and temporal accuracy were high, and pitch accuracy improved when either pitch or temporal sequences repeated over trials. Repetition of either pitch or temporal sequences was associated with linear BOLD decrease in frontal-parietal brain regions including dorsal and ventral premotor cortex, pre-SMA, and superior parietal cortex. Pitch sequence repetition (in contrast to temporal sequence repetition) was associated with linear BOLD decrease in the intraparietal sulcus (IPS) while pianists listened to melodies they were about to perform. Decreased BOLD response in IPS also predicted increase in pitch accuracy only when pitch sequences repeated. Thus, behavioral performance and neural response in sensorimotor mapping networks were sensitive to both pitch and temporal structure, suggesting that pitch and temporal structure are largely integrated in auditory-motor transformations. IPS may be involved in transforming pitch sequences into spatial coordinates for accurate piano performance.

  17. A high volume, batch mode {sup 129}Xe polarizer

    Energy Technology Data Exchange (ETDEWEB)

    Wojna-Pelczar, Anna, E-mail: anna.wojna.pelczar@mail.muni.cz [Central European Institute of Technology, Masaryk University, Brno (Czech Republic); Formerly: Marian Smoluchowski Institute of Physics, Jagiellonian University, Kraków (Poland); Pałasz, Tadeusz [Marian Smoluchowski Institute of Physics, Jagiellonian University, Kraków (Poland)

    2017-06-01

    Numerous designs of optical gas polarizers have been proposed, broadening possible applications of the hyperpolarized gases as contrast agents in magnetic resonance imaging. We present a home–made {sup 129}Xe polarizer based on the spin exchange optical pumping method. The polarizer operates under 1 bar of the gas mixture (at the maximum temperature of 160 °C) in a high volume optical cell (5025 cm{sup 3}). Approximately 100 cm{sup 3} of {sup 129}Xe polarized at 1.50±0.37% is produced in a single cycle of polarization. Operation under standard pressure imposes polarization transfer mainly via van der Waals molecules, resulting in the efficient spin exchange between rubidium and {sup 129}Xe atoms. The design, construction and operation of the polarizer are described in details.

  18. Investigation of a metallic photonic crystal high power microwave mode converter

    Directory of Open Access Journals (Sweden)

    Dong Wang

    2015-02-01

    Full Text Available It is demonstrated that an L band metallic photonic crystal TEM-TE11 mode converter is suitable for narrow band high power microwave application. The proposed mode converter is realized by partially filling metallic photonic crystals along azimuthal direction in a coaxial transmission line for phase-shifting. A three rows structure is designed and simulated by commercial software CST Microwave Studio. Simulation results show that its conversion efficiency is 99% at the center frequency 1.58 GHz. Over the frequency range of 1.56-1.625 GHz, the conversion efficiency exceeds 90 %, with a corresponding bandwidth of 4.1 %. This mode converter has a gigawatt level power handling capability which is suitable for narrow band high power microwave application. Using magnetically insulated transmission line oscillator(MILO as a high power microwave source, particle-in-cell simulation is carried out to test the performance of the mode converter. The expected TE11 mode microwave output is obtained and the MILO works well. Mode conversion performance of the converter is tested by far-field measurement method. And the experimental result confirms the validity of our design. Then, high power microwave experiment is carried out on a Marx-driven Blumlein water line pulsed power accelerator. Microwave frequency, radiated pattern and power are measured in the far-field region and the results agree well with simulation results. The experiment also reveals that no microwave breakdown or pulse shortening took place in the experimental setup.

  19. Whispering gallery mode lasing in high quality GaAs/AlAs pillar microcavities

    Science.gov (United States)

    Jaffrennou, P.; Claudon, J.; Bazin, M.; Malik, N. S.; Reitzenstein, S.; Worschech, L.; Kamp, M.; Forchel, A.; Gérard, J.-M.

    2010-02-01

    We report whispering gallery mode (WGM) lasing from high quality GaAs/AlAs micropillars with embedded InAs quantum dots, under continuous optical pumping. For temperatures ranging from 5 to 100 K, simultaneous lasing from TE1,1,m WGMs is observed for pillar diameters in the 3-4 μm range. Spectral linewidths and energy shifts of the lasing modes are analyzed as a function of the pump power. Thanks to the efficient heat sinking provided by the micropillar geometry, a clear line narrowing is observed above threshold. Moreover, the lasing mode energy remains stable for pump power as large as six times the lasing threshold.

  20. Highly tunable large core single-mode liquid crystal photonic bandgap fiber

    DEFF Research Database (Denmark)

    Alkeskjold, Thomas Tanggaard; Lægsgaard, Jesper; Bjarklev, Anders Overgaard

    2006-01-01

    We demonstrate a highly tunable photonic bandgap fiber, which has a large-core diameter of 25 mu m and an effective mode area of 440 mu m(2). The tunability is achieved by infiltrating the air holes of a photonic crystal fiber with an optimized liquid-crystal mixture having a large temperature...... gradient of the refractive indices at room temperature. A bandgap tuning sensitivity of 27 nm/degrees C is achieved at room temperature. The insertion loss is estimated to be less than 0.5 dB and caused mainly by coupling loss between the index-guided mode and the bandgap-guided mode. (c) 2006 Optical...

  1. A Concept of Multi-Mode High Spectral Resolution Lidar Using Mach-Zehnder Interferometer

    Directory of Open Access Journals (Sweden)

    Jin Yoshitaka

    2016-01-01

    Full Text Available In this paper, we present the design of a High Spectral Resolution Lidar (HSRL using a laser that oscillates in a multi-longitudinal mode. Rayleigh and Mie scattering components are separated using a Mach-Zehnder Interferometer (MZI with the same free spectral range (FSR as the transmitted laser. The transmitted laser light is measured as a reference signal with the same MZI. By scanning the MZI periodically with a scanning range equal to the mode spacing, we can identify the maximum Mie and the maximum Rayleigh signals using the reference signal. The cross talk due to the spectral width of each laser mode can also be estimated.

  2. Changes in pitch height elicit both language-universal and language-dependent changes in neural representation of pitch in the brainstem and auditory cortex.

    Science.gov (United States)

    Krishnan, Ananthanarayan; Suresh, Chandan H; Gandour, Jackson T

    2017-03-27

    Language experience shapes encoding of pitch-relevant information at both brainstem and cortical levels of processing. Pitch height is a salient dimension that orders pitch from low to high. Herein we investigate the effects of language experience (Chinese, English) in the brainstem and cortex on (i) neural responses to variations in pitch height, (ii) presence of asymmetry in cortical pitch representation, and (iii) patterns of relative changes in magnitude of pitch height between these two levels of brain structure. Stimuli were three nonspeech homologs of Mandarin Tone 2 varying in pitch height only. The frequency-following response (FFR) and the cortical pitch-specific response (CPR) were recorded concurrently. At the Fz-linked T7/T8 site, peak latency of Na, Pb, and Nb decreased with increasing pitch height for both groups. Peak-to-peak amplitude of Na-Pb and Pb-Nb increased with increasing pitch height across groups. A language-dependent effect was restricted to Na-Pb; the Chinese had larger amplitude than the English group. At temporal sites (T7/T8), the Chinese group had larger amplitude, as compared to English, across stimuli, but also limited to the Na-Pb component and right temporal site. In the brainstem, F0 magnitude decreased with increasing pitch height; Chinese had larger magnitude across stimuli. A comparison of CPR and FFR responses revealed distinct patterns of relative changes in magnitude common to both groups. CPR amplitude increased and FFR amplitude decreased with increasing pitch height. Experience-dependent effects on CPR components vary as a function of neural sensitivity to pitch height within a particular temporal window (Na-Pb). Differences between the auditory brainstem and cortex imply distinct neural mechanisms for pitch extraction at both levels of brain structure. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

  3. Modified Adaptive Control for Region 3 Operation in the Presence of Wind Turbine Structural Modes

    Science.gov (United States)

    Frost, Susan Alane; Balas, Mark J.; Wright, Alan D.

    2010-01-01

    Many challenges exist for the operation of wind turbines in an efficient manner that is reliable and avoids component fatigue and failure. Turbines operate in highly turbulent environments resulting in aerodynamic loads that can easily excite turbine structural modes, possibly causing component fatigue and failure. Wind turbine manufacturers are highly motivated to reduce component fatigue and failure that can lead to loss of revenue due to turbine down time and maintenance costs. The trend in wind turbine design is toward larger, more flexible turbines that are ideally suited to adaptive control methods due to the complexity and expense required to create accurate models of their dynamic characteristics. In this paper, we design an adaptive collective pitch controller for a high-fidelity simulation of a utility-scale, variable-speed horizontal axis wind turbine operating in Region 3. The objective of the adaptive pitch controller is to regulate generator speed, accommodate wind gusts, and reduce the excitation of structural modes in the wind turbine. The control objective is accomplished by collectively pitching the turbine blades. The adaptive collective pitch controller for Region 3 was compared in simulations with a baseline classical Proportional Integrator (PI) collective pitch controller. The adaptive controller will demonstrate the ability to regulate generator speed in Region 3, while accommodating gusts, and reducing the excitation of certain structural modes in the wind turbine.

  4. Quasi-B-mode generated by high-frequency gravitational waves and corresponding perturbative photon fluxes

    Energy Technology Data Exchange (ETDEWEB)

    Li, Fangyu, E-mail: cqufangyuli@hotmail.com [Institute of Gravitational Physics, Department of Physics, Chongqing University, Chongqing 400044 (China); Wen, Hao [Institute of Gravitational Physics, Department of Physics, Chongqing University, Chongqing 400044 (China); State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing 100190 (China); Fang, Zhenyun [Institute of Gravitational Physics, Department of Physics, Chongqing University, Chongqing 400044 (China); Wei, Lianfu; Wang, Yiwen; Zhang, Miao [Quantum Optoelectronics Laboratory, Southwest Jiaotong University, Chengdu 610031 (China)

    2016-10-15

    Interaction of very low-frequency primordial (relic) gravitational waves (GWs) to cosmic microwave background (CMB) can generate B-mode polarization. Here, for the first time we point out that the electromagnetic (EM) response to high-frequency GWs (HFGWs) would produce quasi-B-mode distribution of the perturbative photon fluxes. We study the duality and high complementarity between such two B-modes, and it is shown that such two effects are from the same physical origin: the tensor perturbation of the GWs and not the density perturbation. Based on this quasi-B-mode in HFGWs and related numerical calculation, it is shown that the distinguishing and observing of HFGWs from the braneworld would be quite possible due to their large amplitude, higher frequency and very different physical behaviors between the perturbative photon fluxes and background photons, and the measurement of relic HFGWs may also be possible though face to enormous challenge.

  5. Quasi-B-mode generated by high-frequency gravitational waves and corresponding perturbative photon fluxes

    Directory of Open Access Journals (Sweden)

    F.Y. Fangyu Li

    2016-10-01

    Full Text Available Interaction of very low-frequency primordial (relic gravitational waves (GWs to cosmic microwave background (CMB can generate B-mode polarization. Here, for the first time we point out that the electromagnetic (EM response to high-frequency GWs (HFGWs would produce quasi-B-mode distribution of the perturbative photon fluxes. We study the duality and high complementarity between such two B-modes, and it is shown that such two effects are from the same physical origin: the tensor perturbation of the GWs and not the density perturbation. Based on this quasi-B-mode in HFGWs and related numerical calculation, it is shown that the distinguishing and observing of HFGWs from the braneworld would be quite possible due to their large amplitude, higher frequency and very different physical behaviors between the perturbative photon fluxes and background photons, and the measurement of relic HFGWs may also be possible though face to enormous challenge.

  6. SEMICONDUCTOR DEVICES: A novel high voltage start up circuit for an integrated switched mode power supply

    Science.gov (United States)

    Hao, Hu; Xingbi, Chen

    2010-09-01

    A novel high voltage start up circuit for providing an initial bias voltage to an integrated switched mode power supply (SMPS) is presented. An enhanced mode VDMOS transistor, the gate of which is biased by a floating p-island, is used to provide start up current and sustain high voltage. An NMOS transistor having a high source to ground breakdown voltage is included to extend the bias voltage range to the SMPS. Simulation results indicate that the high voltage start up circuit can start and restart as designed. The proposed structure is believed to be more energy saving and cost-effective compared with other solutions.

  7. Discriminating male and female voices: differentiating pitch and gender.

    Science.gov (United States)

    Latinus, Marianne; Taylor, Margot J

    2012-04-01

    Gender is salient, socially critical information obtained from faces and voices, yet the brain processes underlying gender discrimination have not been well studied. We investigated neural correlates of gender processing of voices in two ERP studies. In the first, ERP differences were seen between female and male voices starting at 87 ms, in both spatial-temporal and peak analyses, particularly the fronto-central N1 and P2. As pitch differences may drive gender differences, the second study used normal, high- and low-pitch voices. The results of these studies suggested that differences in pitch produced early effects (27-63 ms). Gender effects were seen on N1 (120 ms) with implicit pitch processing (study 1), but were not seen with manipulations of pitch (study 2), demonstrating that N1 was modulated by attention. P2 (between 170 and 230 ms) discriminated male from female voices, independent of pitch. Thus, these data show that there are two stages in voice gender processing; a very early pitch or frequency discrimination and a later more accurate determination of gender at the P2 latency.

  8. Impaired memory for pitch in congenital amusia.

    Science.gov (United States)

    Gosselin, Nathalie; Jolicoeur, Pierre; Peretz, Isabelle

    2009-07-01

    We examined memory for pitch in congenital amusia in two tasks. In one task, we varied the pitch distance between the target and comparison tone from 4 to 9 semitones and inserted either a silence or 6 interpolated tones between the tones to be compared. In a second task, we manipulated the number of pitches to be retained in sequences of length 1, 3, or 5. Amusics' sensitivity to pitch distance was exacerbated by the presence of interpolated tones, and amusics' performance was more strongly affected by the number of pitches to maintain in memory than controls. A pitch perception deficit could not account for the pitch memory deficit of amusics.

  9. Measurements of High Order Modes in High Phase Advance Damped Detuned Accelerating Structure for NLC

    CERN Document Server

    Khabiboulline, N; Carter, H

    2004-01-01

    The RF Technology Development group at Fermilab is working together with the NLC and JLC groups at SLAC and KEK on developing technology for room temperature X-band accelerating structures for a future linear collider. We have built several series of structures for high gradient tests. We have also built 150° phase advance per cell, 60 cm long, damped and detuned structures (HDDS or FXC series). Some of these structures will be used for the 8-pack test at SLAC by the end of 2004, as part of the JLC/NLC effort to demonstrate the readiness of room temperature RF technology for a linear collider. HDSS structures are very close to the final design for the linear collider, and it was very interesting to study the properties of high order modes in the structures produced by semi-industrial methods. In this study advanced RF technique and methods developed at Fermilab for structure low power testing and tuning have been used. The results of these measurements are presented in this paper.

  10. Perceiving pitch absolutely: comparing absolute and relative pitch possessors in a pitch memory task

    National Research Council Canada - National Science Library

    Schulze, Katrin; Gaab, Nadine; Schlaug, Gottfried

    2009-01-01

    .... The aim of this fMRI study was to examine the neural network underlying AP using a pitch memory experiment and contrasting two groups of musicians with each other, those that have AP and those that do...

  11. Vibration Mode Observation of Piezoelectric Disk-type Resonator by High Frequency Laser Doppler Vibrometer

    Science.gov (United States)

    Matsumura, Takeshi; Esashi, Masayoshi; Harada, Hiroshi; Tanaka, Shuji

    For future mobile phones based on cognitive radio technology, a compact multi-band RF front-end architecture is strongly required and an integrated multi-band RF filter bank is a key component in it. Contour-mode resonators are receiving increased attention for a multi-band filter solution, because its resonant frequency is mainly determined by its size and shape, which are defined by lithography. However, spurious responses including flexural vibration are also excited due to its thin structure. To improve resonator performance and suppress spurious modes, visual observation with a laser probe system is very effective. In this paper, we have prototyped a mechanically-coupled disk-array filter, which consists of a Si disk and 2 disk-type resonators of higher-order wine-glass mode, and observed its vibration modes using a high-frequency laser-Doppler vibrometer (UHF-120, Polytec, Inc.). As a result, it was confirmed that higher order wine-glass mode vibration included a compound displacement, and that its out-of-plane vibration amplitude was much smaller than other flexural spurious modes. The observed vibration modes were compared with FEM (Finite Element Method) simulation results. In addition, it was also confirmed that the fabrication error, e.g. miss-alignment, induced asymmetric vibration.

  12. Pitch strength of normal and dysphonic voices

    OpenAIRE

    Shrivastav, Rahul; Eddins, David A.; Anand, Supraja

    2012-01-01

    Two sounds with the same pitch may vary from each other based on saliency of their pitch sensation. This perceptual attribute is called “pitch strength.” The study of voice pitch strength may be important in quantifying of normal and pathological qualities. The present study investigated how pitch strength varies across normal and dysphonic voices. A set of voices (vowel /a/) selected from the Kay Elemetrics Disordered Voice Database served as the stimuli. These stimuli demonstrated a wide ra...

  13. Context effects on pitch perception in musicians and nonmusicians

    DEFF Research Database (Denmark)

    Brattico, E; Naatanen, R; Tervaniemi, M

    2001-01-01

    Behavioral evidence indicates that musical context facilitates pitch discrimination. In the present study, we sought to determine whether pitch context and its familiarity might affect brain responses to pitch change even at the preattentive level. Ten musicians and 10 nonmusicians, while...... arithmetically determined tone frequencies, the deviant not causing any change of mode. The no-context condition included only third-position tones. All deviants elicited the change-specific mismatch negativity component of the event-related potentials in both groups of subjects. In both musicians...... is generally enhanced in a familiar context. Moreover, the latency of the mismatch negativity was shorter for musicians than for nonmusicians in both the familiar and unfamiliar conditions, whereas no difference between groups was observed in the no-context condition. This finding indicates that, in response...

  14. High power L-band mode-locked fiber laser based on topological insulator saturable absorber.

    Science.gov (United States)

    Meng, Yichang; Semaan, Georges; Salhi, Mohamed; Niang, Alioune; Guesmi, Khmaies; Luo, Zhi-Chao; Sanchez, Francois

    2015-09-07

    We demonstrate a passive mode-locked Er:Yb doped double-clad fiber laser using a microfiber-based topological insulator (Bi(2)Se(3)) saturable absorber (TISA). By optimizing the cavity loss and output coupling ratio, the mode-locked fiber laser can operate in L-band with high average output power. With the highest pump power of 5 W, 91st harmonic mode locking of soliton bunches with average output power of 308 mW was obtained. This is the first report that the TISA based erbium-doped fiber laser operating above 1.6 μm and is also the highest output power yet reported in TISA based passive mode-locked fiber laser.

  15. Low- and high-mode separation of short wavelength turbulence in dithering Wendelstein 7-AS plasmas

    DEFF Research Database (Denmark)

    Basse, N.P.; Zoletnik, S.; Saffman, M.

    2002-01-01

    measurements can be fitted with the same exponents in L- and H-mode. Correlations between the density fluctuations, the H-alpha-signal and magnetic fluctuations as measured by Mirnov coils were analyzed. Correlation calculations using 50 ms time windows (several dithering periods) with time lag steps of 100......) stellarator [H. Renner , Plasma Phys. Control. Fusion 31, 1579 (1989)]. The experimental setup and discharge properties are described. H-alpha-light observing an inner limiter was used to separate low confinement (L)- and H-mode phases of the plasma; the separated density fluctuations are characterized....... It was found that L- (H-) mode fluctuations dominate at high (low) frequencies, respectively, and that they possess well-defined and distinguishable scaling properties. Wavenumber spectra for L- and H-mode measurements are calculated and fitted by power-laws and exponential functions. The separated...

  16. Nonlinear resonances of three modes in a high-Tc superconducting magnetic levitation system

    Science.gov (United States)

    Sasaki, Masahiko; Sakaguchi, Ryunosuke; Sugiura, Toshihiko

    2013-11-01

    In a high-Tc superconducting magnetic levitation system, an object can levitate without control and contact. So it is expected to be applied to magnetically levitated transportation. To use it safely, lightening the levitated object is necessary. But this reduces the bending stiffness of the object. Besides, the system has nonlinearity. Therefore nonlinear elastic vibration can occur. This study focused on how plural nonlinear elastic vibrations of the 1st, 2nd and 3rd modes simultaneously occur. Our numerical calculation and experiment found out that the three modes simultaneously resonate when the amplitude of the 2nd mode is large enough whereas only the 2nd mode resonates when it is small.

  17. Endlessly single-mode photonic crystal fiber as a high resolution probe.

    Science.gov (United States)

    Valtna-Lukner, Heli; Repän, Jaagup; Valdma, Sandhra-Mirella; Piksarv, Peeter

    2016-11-20

    We sample ultra-broadband light, focused onto a diffraction-limited spot, to an endlessly single-mode photonic crystal fiber (ESM) and detect both the field amplitude and phase using a SEA TADPOLE interferometer. We resolve spatial features up to 2.5 times finer than the fiber mode size while sampling the periodic features of the bipolar oscillating field in the transverse section. The resolution enhancement is expected also in other types of single-mode fibers in intensity measurements and leads to an inexpensive method for characterizing the point-spread function of such optical fields, e.g., diffraction-limited spots from microscope objectives. In addition, we demonstrate the guidance of a high-NA light field in the fine structure of an ESM fiber mode. The results are especially valuable for devices where a fiber tip acts as an input slit and defines the spatial resolution, e.g., fiber-based interferometers, spectrometers, and sensors.

  18. Rapid pitch correction in choir singers.

    Science.gov (United States)

    Grell, Anke; Sundberg, Johan; Ternström, Sten; Ptok, Martin; Altenmüller, Eckart

    2009-07-01

    Highly and moderately skilled choral singers listened to a perfect fifth reference, with the instruction to complement the fifth such that a major triad resulted. The fifth was suddenly and unexpectedly shifted in pitch, and the singers' task was to shift the fundamental frequency of the sung tone accordingly. The F0 curves during the transitions often showed two phases, an initial quick and large change followed by a slower and smaller change, apparently intended to fine-tune voice F0 to complement the fifth. Anesthetizing the vocal folds of moderately skilled singers tended to delay the reaction. The means of the response times varied in the range 197- 259 ms depending on direction and size of the pitch shifts, as well as on skill and anesthetization.

  19. Voice Pitch Influences Perceptions of Sexual Infidelity

    Directory of Open Access Journals (Sweden)

    Jillian J.M. O'Connor

    2011-01-01

    Full Text Available Sexual infidelity can be costly to members of both the extra-pair and the paired couple. Thus, detecting infidelity risk is potentially adaptive if it aids in avoiding cuckoldry or loss of parental and relationship investment. Among men, testosterone is inversely related to voice pitch, relationship and offspring investment, and is positively related to the pursuit of short-term relationships, including extra-pair sex. Among women, estrogen is positively related to voice pitch, attractiveness, and the likelihood of extra-pair involvement. Although prior work has demonstrated a positive relationship between men's testosterone levels and infidelity, this study is the first to investigate attributions of infidelity as a function of sexual dimorphism in male and female voices. We found that men attributed high infidelity risk to feminized women's voices, but not significantly more often than did women. Women attributed high infidelity risk to masculinized men's voices at significantly higher rates than did men. These data suggest that voice pitch is used as an indicator of sexual strategy in addition to underlying mate value. The aforementioned attributions may be adaptive if they prevent cuckoldry and/or loss of parental and relationship investment via avoidance of partners who may be more likely to be unfaithful.

  20. Voice pitch influences perceptions of sexual infidelity.

    Science.gov (United States)

    O'Connor, Jillian J M; Re, Daniel E; Feinberg, David R

    2011-02-28

    Sexual infidelity can be costly to members of both the extra-pair and the paired couple. Thus, detecting infidelity risk is potentially adaptive if it aids in avoiding cuckoldry or loss of parental and relationship investment. Among men, testosterone is inversely related to voice pitch, relationship and offspring investment, and is positively related to the pursuit of short-term relationships, including extra-pair sex. Among women, estrogen is positively related to voice pitch, attractiveness, and the likelihood of extra-pair involvement. Although prior work has demonstrated a positive relationship between men's testosterone levels and infidelity, this study is the first to investigate attributions of infidelity as a function of sexual dimorphism in male and female voices. We found that men attributed high infidelity risk to feminized women's voices, but not significantly more often than did women. Women attributed high infidelity risk to masculinized men's voices at significantly higher rates than did men. These data suggest that voice pitch is used as an indicator of sexual strategy in addition to underlying mate value. The aforementioned attributions may be adaptive if they prevent cuckoldry and/or loss of parental and relationship investment via avoidance of partners who may be more likely to be unfaithful.

  1. A study of the eigenvectors of the low-frequency vibrational modes in crystalline adenosine via high pressure Raman spectroscopy.

    Science.gov (United States)

    Lee, Scott A; Pinnick, David A; Anderson, A

    2014-12-01

    High-pressure Raman spectroscopy has been used to study the eigenvectors and eigenvalues of the vibrational modes of crystalline adenosine at 295 K by evaluating the logarithmic derivative of the vibrational frequency with respect to pressure: [Formula: see text]. Crystalline samples of molecular materials such as adenosine will have vibrational modes that are localized within a molecular unit ("internal" modes) as well as modes in which the molecular units vibrate against each other ("external" modes). The value of the logarithmic derivative is found to be a diagnostic probe of the nature of the eigenvector of the vibrational modes. Stretching modes which are predominantly internal to the molecule have low logarithmic derivatives while external modes have higher logarithmic derivatives. Particular interest is paid to the low-frequency (≤150 cm(-1)) modes. Based on the pressure dependence of its logarithmic derivative, a mode near 49 cm(-1) is identified as internal mode. The other modes below 400 cm(-1) have pressure dependences of their logarithmic derivatives consistent with being either (1) modes which are mainly external, meaning that the molecules of the unit cell vibrate against each other in translational or librational motions (or linear combinations thereof), or (2) torsional or bending modes involving a large number of atoms, mainly within a molecule. The modes above 400 cm(-1) all have pressure dependences of their logarithmic derivatives consistent with being mainly internal modes.

  2. Nonlinear MHD simulations of QH-mode DIII-D plasmas and implications for ITER high Q scenarios

    Science.gov (United States)

    Liu, F.; Huijsmans, G. T. A.; Loarte, A.; Garofalo, A. M.; Solomon, W. M.; Hoelzl, M.; Nkonga, B.; Pamela, S.; Becoulet, M.; Orain, F.; Van Vugt, D.

    2018-01-01

    In nonlinear MHD simulations of DIII-D QH-mode plasmas it has been found that low n kink/peeling modes (KPMs) are unstable and grow to a saturated kink-peeling mode. The features of the dominant saturated KPMs, which are localised toroidally by nonlinear coupling of harmonics, such as mode frequencies, density fluctuations and their effect on pedestal particle and energy transport, are in good agreement with the observations of the edge harmonic oscillation typically present in DIII-D QH-mode experiments. The nonlinear evolution of MHD modes including both kink-peeling modes and ballooning modes, is investigated through MHD simulations by varying the pedestal current and pressure relative to the initial conditions of DIII-D QH-mode plasma. The edge current and pressure at the pedestal are key parameters for the plasma either saturating to a QH-mode regime or a ballooning mode dominant regime. The influence of E × B flow and its shear on the QH-mode plasma has been investigated. E × B flow shear has a strong stabilisation effect on the medium to high-n modes but is destabilising for the n = 2 mode. The QH-mode extrapolation results of an ITER Q = 10 plasma show that the pedestal currents are large enough to destabilise n = 1–5 KPMs, leading to a stationary saturated kink-peeling mode.

  3. Image quality, radiation dose, and diagnostic accuracy of prospectively ECG-triggered high-pitch coronary CT angiography at 70 kVp in a clinical setting: comparison with invasive coronary angiography

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Long Jiang; Qi, Li; Zhou, Chang Sheng; Zhao, Yan E.; Li, Xie; Lu, Guang Ming [Jinling Hospital, Medical School of Nanjing University, Department of Medical Imaging, Nanjing, Jiangsu (China); Wang, Yining; Cao, Jian; Jin, Zhengyu [Peking Union Medical College Hospital, Department of Radiology, Beijing (China); Schoepf, U.J. [Jinling Hospital, Medical School of Nanjing University, Department of Medical Imaging, Nanjing, Jiangsu (China); Medical University of South Carolina, Division of Cardiovascular Imaging, Charleston, SC (United States); Meinel, Felix G. [Medical University of South Carolina, Division of Cardiovascular Imaging, Charleston, SC (United States); Ludwig-Maximilians-University Hospital, Institute for Clinical Radiology, Munich (Germany); Bayer, Richard R. [Medical University of South Carolina, Division of Cardiovascular Imaging, Charleston, SC (United States); Gong, Jian Bin [Jinling Hospital, Medical School of Nanjing University, Department of Cardiology, Nanjing, Jiangsu (China)

    2016-03-15

    To investigate image quality, radiation dose, and diagnostic performance of prospectively ECG-triggered high-pitch coronary CT angiography (CCTA) at 70 kVp compared to invasive coronary angiography (ICA) as reference standard. Forty-three patients underwent prospectively ECG-triggered high-pitch CCTA at 70 kVp using 30 cc (11 g iodine) contrast medium and ICA. Subjective and objective image quality was evaluated for each CCTA study. CCTA performance for diagnosing ≥50 % stenosis was assessed. Results were stratified according to heart rate (HR), body mass index (BMI), Agatston score, and image quality. At CCTA, 94.3 % (500/530) of coronary segments were of diagnostic quality. Using ICA as reference standard, sensitivity and accuracy were 100 % and 93.0 % on a per-patient basis. Per-vessel and per-segment performances were 92.2 % and 89.5 %; 79.5 % and 88.3 %, respectively. No differences were found in diagnostic accuracy between different HR, BMI, and calcification subgroups (all P > 0.05) on a per-patient basis. However, low image quality reduced diagnostic accuracy on a per-patient, per-vessel and per-segment basis (all P < 0.05). The mean effective radiation dose was 0.2 ± 0.0 mSv. Our presented protocol results in an effective radiation dose of 0.2 mSv and high diagnostic accuracy for stenosis detection in a selected, non-obese population. (orig.)

  4. A HIGH PERFORMANCE FULLY DIFFERENTIAL PURE CURRENT MODE OPERATIONAL AMPLIFIER AND ITS APPLICATIONS

    Directory of Open Access Journals (Sweden)

    SEYED JAVAD AZHARI

    2012-08-01

    Full Text Available In this paper a novel high performance all current-mode fully-differential (FD Current mode Operational Amplifier (COA in BIPOLAR technology is presented. The unique true current mode simple structure grants the proposed COA the largest yet reported unity gain frequency while providing low voltage low power operation. Benefiting from some novel ideas, it also exhibits high gain, high common mode rejection ratio (CMRR, high power supply rejection ratio (PSRR, high output impedance, low input impedance and most importantly high current drive capability. Its most important parameters are derived and its performance is proved by PSPICE simulations using 0.8 μm BICMOS process parameters at supply voltage of ±1.2V indicating the values of 82.4 dB,52.3º, 31.5 Ω, 31.78 MΩ, 179.2 dB, 2 mW and 698 MHz for gain, phase margin, input impedance, output impedance, CMRR, power and unity gain frequency respectively. Its CMRR also shows very high frequency of 2.64 GHz at zero dB. Its very high PSRR+/PSRR- of 182 dB/196 dB makes the proposed COA a highly suitable block in Mixed-Mode (SOC chips. Most favourably it can deliver up to ±1.5 mA yielding a high current drive capability exceeding 25. To demonstrate the performance of the proposed COA, it is used to realize a constant bandwidth voltage amplifier and a high performance Rm amplifier.

  5. Giant Faraday Rotation of High-Order Plasmonic Modes in Graphene-Covered Nanowires.

    Science.gov (United States)

    Kuzmin, Dmitry A; Bychkov, Igor V; Shavrov, Vladimir G; Temnov, Vasily V

    2016-07-13

    Plasmonic Faraday rotation in nanowires manifests itself in the rotation of the spatial intensity distribution of high-order surface plasmon polariton (SPP) modes around the nanowire axis. Here we predict theoretically the giant Faraday rotation for SPPs propagating on graphene-coated magneto-optically active nanowires. Upon the reversal of the external magnetic field pointing along the nanowire axis some high-order plasmonic modes may be rotated by up to ∼100° on the length scale of about 500 nm at mid-infrared frequencies. Tuning the carrier concentration in graphene by chemical doping or gate voltage allows for controlling SPP-properties and notably the rotation angle of high-order azimuthal modes. Our results open the door to novel plasmonic applications ranging from nanowire-based Faraday isolators to the magnetic control in quantum-optical applications.

  6. QUIESCENT H-MODE, AN ELM-FREE HIGH-CONFINEMENT MODE ON DIII-D WITH POTENTIAL FOR STATIONARY STATE OPERATION

    Energy Technology Data Exchange (ETDEWEB)

    WEST,WP; BURRELL,KH; deGRASSIE,JS; DOYLE,EJ; GREENFIELD,CM; LASNIER,CJ; SNYDER,PB; ZENG,L

    2003-08-01

    OAK-B135 The quiescent H-mode (QH-mode) is an ELM-free and stationary state mode of operation discovered on DIII-D. This mode achieves H-mode levels of confinement and pedestal pressure while maintaining constant density and radiated power. The elimination of edge localized modes (ELMs) and their large divertor loads while maintaining good confinement and good density control is of interest to next generation tokamaks. This paper reports on the correlations found between selected parameters in a QH-mode database developed from several hundred DIII-D counter injected discharges. Time traces of key plasma parameters from a QH-mode discharge are shown. On DIII-D the negative going plasma current (a) indicates that the beam injection direction is counter to the plasma current direction, a common feature of all QH-modes. The D{sub {alpha}} time behavior (c) shows that soon after high powered beam heating (b) is applied, the discharge makes a transition to ELMing H-mode, then the ELMs disappear, indicating the start of the QH period that lasts for the remainder of the high power beam heating (3.5 s). Previously published work showing density and temperature profiles indicates that long-pulse, high-triangularity QH discharges develop an internal transport barrier in combination with the QH edge barrier. These discharges are known as quiescent, double-barrier discharges (QDB). The H-factor (d) and stored energy (c) rise then saturate at a constant level and the measured axial and minimum safety factors remain above 1.0 for the entire QH duration. During QDB operation the performance of the plasma can be very good, with {beta}{sub N}*H{sub 89L} product reaching 7 for > 10 energy confinement times. These discharges show promise that a stationary state can be achieved.

  7. Preparation and Characterization of Mesophase Pitch via Co-Carbonization of Waste Polyethylene]Petroleum Pitch

    National Research Council Canada - National Science Library

    Youliang Cheng Lu Yang Tao Luo Changqing Fang Jian Su Jian Hui

    2015-01-01

    The low-cost petroleum pitch and waste polyethylene (WPE) were used as raw materials to prepare the mesophase pitch by co-carbonization method and the forming mechanization of mesophase pitch was also investigated...

  8. Comparison of pitch rate history effects on dynamic stall

    Science.gov (United States)

    Chandrasekhara, M. S.; Carr, Lawrence W.; Ahmed, S.

    1992-01-01

    Dynamic stall of an airfoil is a classic case of forced unsteady separated flow. Flow separation is brought about by large incidences introduced by the large amplitude unsteady pitching motion of an airfoil. One of the parameters that affects the dynamic stall process is the history of the unsteady motion. In addition, the problem is complicated by the effects of compressibility that rapidly appear over the airfoil even at low Mach numbers at moderately high angles of attack. Consequently, it is of interest to know the effects of pitch rate history on the dynamic stall process. This abstract compares the results of a flow visualization study of the problem with two different pitch rate histories, namely, oscillating airfoil motion and a linear change in the angle of attack due to a transient pitching motion.

  9. Controlled assembly of organic whispering-gallery-mode microlasers as highly sensitive chemical vapor sensors.

    Science.gov (United States)

    Gao, Miaomiao; Wei, Cong; Lin, Xianqing; Liu, Yuan; Hu, Fengqin; Zhao, Yong Sheng

    2017-03-09

    We demonstrate the fabrication of organic high Q active whispering-gallery-mode (WGM) resonators from π-conjugated polymer by a controlled emulsion-solvent-evaporation method, which can simultaneously provide optical gain and act as an effective resonant cavity. By measuring the shift of their lasing modes on exposure to organic vapor, we successfully monitored the slight concentration variation in the chemical gas. These microlaser sensors demonstrated high detection sensitivity and good signal repeatability under continuous chemical gas treatments. The results offer an effective strategy to design miniaturized optical sensors.

  10. High Order Sliding Mode Control of Doubly-fed Induction Generator under Unbalanced Grid Faults

    DEFF Research Database (Denmark)

    Zhu, Rongwu; Chen, Zhe; Wu, Xiaojie

    2013-01-01

    This paper deals with a doubly-fed induction generator-based (DFIG) wind turbine system under grid fault conditions such as: unbalanced grid voltage, three-phase grid fault, using a high order sliding mode control (SMC). A second order sliding mode controller, which is robust with respect...... to matched internal or external disturbances, fast transient response and finite reaching time, is employed to reduce chattering phenomenon caused by high frequency switching of SMC, which serious exists in lower order SMC, and to overcome parameter dependence of traditional proportional integral (PI...

  11. Complexity control algorithm based on adaptive mode selection for interframe coding in high efficiency video coding

    Science.gov (United States)

    Chen, Gang; Yang, Bing; Zhang, Xiaoyun; Gao, Zhiyong

    2017-07-01

    The latest high efficiency video coding (HEVC) standard significantly increases the encoding complexity for improving its coding efficiency. Due to the limited computational capability of handheld devices, complexity constrained video coding has drawn great attention in recent years. A complexity control algorithm based on adaptive mode selection is proposed for interframe coding in HEVC. Considering the direct proportionality between encoding time and computational complexity, the computational complexity is measured in terms of encoding time. First, complexity is mapped to a target in terms of prediction modes. Then, an adaptive mode selection algorithm is proposed for the mode decision process. Specifically, the optimal mode combination scheme that is chosen through offline statistics is developed at low complexity. If the complexity budget has not been used up, an adaptive mode sorting method is employed to further improve coding efficiency. The experimental results show that the proposed algorithm achieves a very large complexity control range (as low as 10%) for the HEVC encoder while maintaining good rate-distortion performance. For the lowdelayP condition, compared with the direct resource allocation method and the state-of-the-art method, an average gain of 0.63 and 0.17 dB in BDPSNR is observed for 18 sequences when the target complexity is around 40%.

  12. Impurity confinement and transport in high confinement regimes without edge localized modes on DIII-D

    Energy Technology Data Exchange (ETDEWEB)

    Grierson, B. A., E-mail: bgriers@pppl.gov; Nazikian, R. M.; Solomon, W. M. [Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States); Burrell, K. H.; Garofalo, A. M.; Belli, E. A.; Staebler, G. M.; Evans, T. E.; Smith, S. P.; Chrobak, C. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); Fenstermacher, M. E. [Lawerence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550 (United States); McKee, G. R. [Department of Engineering Physics, University of Wisconsin-Madison, Madison, Wisconsin 53796 (United States); Orlov, D. M. [Center for Energy Research, University of California San Diego, 9500 Gilman Dr., La Jolla, California 92093-0417 (United States); Chrystal, C. [University of California San Diego, 9500 Gilman Dr., La Jolla, California 92093-0417 (United States)

    2015-05-15

    Impurity transport in the DIII-D tokamak [J. L. Luxon, Nucl. Fusion 42, 614 (2002)] is investigated in stationary high confinement (H-mode) regimes without edge localized modes (ELMs). In plasmas maintained by resonant magnetic perturbation (RMP), ELM-suppression, and QH-mode, the confinement time of fluorine (Z = 9) is equivalent to that in ELMing discharges with 40 Hz ELMs. For selected discharges with impurity injection, the impurity particle confinement time compared to the energy confinement time is in the range of τ{sub p}/τ{sub e}≈2−3. In QH-mode operation, the impurity confinement time is shown to be smaller for intense, coherent magnetic, and density fluctuations of the edge harmonic oscillation than weaker fluctuations. Transport coefficients are derived from the time evolution of the impurity density profile and compared to neoclassical and turbulent transport models NEO and TGLF. Neoclassical transport of fluorine is found to be small compared to the experimental values. In the ELMing and RMP ELM-suppressed plasma, the impurity transport is affected by the presence of tearing modes. For radii larger than the mode radius, the TGLF diffusion coefficient is smaller than the experimental value by a factor of 2–3, while the convective velocity is within error estimates. Low levels of diffusion are observed for radii smaller than the tearing mode radius. In the QH-mode plasma investigated, the TGLF diffusion coefficient is higher inside of ρ=0.4 and lower outside of 0.4 than the experiment, and the TGLF convective velocity is more negative by a factor of approximately 1.7.

  13. Disorders of pitch production in tone deafness

    Directory of Open Access Journals (Sweden)

    Simone eDalla Bella

    2011-07-01

    Full Text Available Singing is as natural as speaking for the majority of people. Yet some individuals (i.e., 10-15% are inaccurate singers, typically performing or imitating pitches and melodies inaccurately. This condition, commonly referred to as tone deafness, has been observed both in the presence and absence of deficient pitch perception. In this article we review the existing literature concerning normal singing, poor-pitch singing, and, briefly, the sources of this condition. Considering that pitch plays a prominent role in the structure of both music and speech we also focus on the possibility that pitch production (or imitation is similarly impaired in poor-pitch singers. Preliminary evidence from our laboratory on poor-pitch singing suggests that pitch imitation may be selectively inaccurate in the music domain without being affected in speech. This finding points to separability of mechanisms subserving pitch production in music and language.

  14. Musical Activity Tunes Up Absolute Pitch Ability

    DEFF Research Database (Denmark)

    Dohn, Anders; Garza-Villarreal, Eduardo A.; Ribe, Lars Riisgaard

    2014-01-01

    Absolute pitch (AP) is the ability to identify or produce pitches of musical tones without an external reference. Active AP (i.e., pitch production or pitch adjustment) and passive AP (i.e., pitch identification) are considered to not necessarily coincide, although no study has properly compared...... these abilities. Using a novel computerized pitch adjustment test, we investigated active AP ability in musicians with and without AP (ages 18-43). We found a significant correlation between active and passive AP indicating that AP possessors (APs) identify and produce pitch equally well. Furthermore, we found...... that APs generally undershoot when adjusting musical pitch, a tendency that decreases when musical activity increases. Finally, APs are less accurate when adjusting the pitch to black key targets than to white key targets. Hence, AP ability may be partly practice-dependent and we speculate that APs may...

  15. Individual blade pitch for yaw control

    Science.gov (United States)

    Navalkar, S. T.; van Wingerden, J. W.; van Kuik, G. A. M.

    2014-06-01

    Individual pitch control (IPC) for reducing blade loads has been investigated and proven successful in recent literature. For IPC, the multi-blade co-ordinate (MBC) transformation is used to process the blade load signals from the rotating to a stationary frame of reference. In the stationary frame of reference, the yaw error of a turbine can be appended to generate IPC actions that are able to achieve turbine yaw control for a turbine in free yaw. In this paper, IPC for yaw control is tested on a high-fidelity numerical model of a commercially produced wind turbine in free yaw. The tests show that yaw control using IPC has the distinct advantage that the yaw system loads and support structure loading are substantially reduced. However, IPC for yaw control also shows a reduction in IPC blade load reduction potential and causes a slight increase in pitch activity. Thus, the key contribution of this paper is the concept demonstration of IPC for yaw control. Further, using IPC for yaw as a tuning parameter, it is shown how the best trade-off between blade loading, pitch activity and support structure loading can be achieved for wind turbine design.

  16. Biomechanics of youth windmill softball pitching.

    Science.gov (United States)

    Werner, Sherry L; Guido, John A; McNeice, Ryan P; Richardson, Jasper L; Delude, Neil A; Stewart, Gregory W

    2005-04-01

    Limited research attention has been paid to the potentially harmful windmill softball pitch. No information is available regarding lower extremity kinetics in softball pitching. The stresses on the throwing arm of youth windmill pitchers are clinically significant and similar to those found for college softball pitchers. Descriptive laboratory study. Three-dimensional, high-speed (240-Hz) video and stride foot force plate (1200 Hz) data were collected on fastballs from 53 youth softball pitchers. Kinematic parameters related to pitching mechanics and resultant kinetics on the throwing-arm elbow and shoulder joints were calculated. Kinetic parameters were compared to those reported for baseball pitchers. Elbow and shoulder joint loads were similar to those found for baseball pitchers and college softball pitchers. Shoulder distraction stress averaged 94% body weight for the youth pitchers. Stride foot ground reaction force patterns were not similar to those reported for baseball pitchers. Vertical and braking force components under the stride foot were in excess of body weight. Excessive distraction stress and joint torques at the throwing-arm elbow and shoulder are similar to those found in baseball pitchers, which suggests that windmill softball pitchers are at risk for overuse injuries. Normative information regarding upper and lower extremity kinematics and kinetics for 12- to 19-year-old softball pitchers has been established.

  17. A study of the eigenvectors of the vibrational modes in crystalline cytidine via high-pressure Raman spectroscopy.

    Science.gov (United States)

    Lee, Scott A; Pinnick, David A; Anderson, A

    2015-01-01

    Raman spectroscopy has been used to study the eigenvectors and eigenvalues of the vibrational modes of crystalline cytidine at 295 K and high pressures by evaluating the logarithmic derivative of the vibrational frequency ω with respect to pressure P: [Formula: see text]. Crystalline samples of molecular materials have strong intramolecular bonds and weak intermolecular bonds. This hierarchy of bonding strengths causes the vibrational optical modes localized within a molecular unit ("internal" modes) to be relatively high in frequency while the modes in which the molecular units vibrate against each other ("external" modes) have relatively low frequencies. The value of the logarithmic derivative is a useful diagnostic probe of the nature of the eigenvector of the vibrational modes because stretching modes (which are predominantly internal to the molecule) have low logarithmic derivatives while external modes have higher logarithmic derivatives. In crystalline cytidine, the modes at 85.8, 101.4, and 110.6 cm(-1) are external in which the molecules of the unit cell vibrate against each other in either translational or librational motions (or some linear combination thereof). All of the modes above 320 cm(-1) are predominantly internal stretching modes. The remaining modes below 320 cm(-1) include external modes and internal modes, mostly involving either torsional or bending motions of groups of atoms within a molecule.

  18. Feeding at a high pitch: Source parameters of narrow band,high-frequency clicks from echolocating off-shore hourglassdolphins and coastal Hector's dolphins

    DEFF Research Database (Denmark)

    Kyhn, Line Anker; Tougaard, Jakob; Jensen, Frants Havmand

    2009-01-01

    (Lagenorhynchus cruciger) and Hector's dolphins (Cephalorhynchus hectori ) were made in the Drake Passage between Tierra del Fuego and the Antarctic Peninsular and Banks Peninsular Akaroa Harbour, New Zealand with a four element hydrophone array. Analysis of source parameters shows that both species produce...... narrow band high-frequency (NBHF) echolocation clicks. Coastal Hector's dolphins produce clicks with a mean peak frequency of 129 kHz, 3 dB bandwidth of 20 kHz, 57 ys, 10 dB duration, and mean apparent source level (ASL) of 177 dB re 1 yPa (p.-p.). The oceanic hourglass dolphins produce clicks with mean...... peak frequency of 126 kHz, 3 dB bandwidth of 8 kHz, 116 ys, 10 dB duration, and a mean estimated ASL of 197 dB re 1 yPa (p.-p.). Thus, hourglass dolphins apparently produce clicks of higher source level, which should allow them to detect prey at more than twice the distance compared to Hector...

  19. Feeding at a high pitch: source parameters of narrow band, high-frequency clicks from echolocating off-shore hourglass dolphins and coastal Hector's dolphins.

    Science.gov (United States)

    Kyhn, Line A; Tougaard, J; Jensen, F; Wahlberg, M; Stone, G; Yoshinaga, A; Beedholm, K; Madsen, P T

    2009-03-01

    Toothed whales depend on echolocation for orientation and prey localization, and source parameters of echolocation clicks from free-ranging animals therefore convey valuable information about the acoustic physiology and behavioral ecology of the recorded species. Recordings of wild hourglass (Lagenorhynchus cruciger) and Hector's dolphins (Cephalorhynchus hectori) were made in the Drake Passage (between Tierra del Fuego and the Antarctic Peninsular) and Banks Peninsular (Akaroa Harbour, New Zealand) with a four element hydrophone array. Analysis of source parameters shows that both species produce narrow band high-frequency (NBHF) echolocation clicks. Coastal Hector's dolphins produce clicks with a mean peak frequency of 129 kHz, 3 dB bandwidth of 20 kHz, 57 micros, 10 dB duration, and mean apparent source level (ASL) of 177 dB re 1 microPa(p.-p.). The oceanic hourglass dolphins produce clicks with mean peak frequency of 126 kHz, 3 dB bandwidth of 8 kHz, 116 micros, 10 dB duration, and a mean estimated ASL of 197 dB re 1 microPa(p.-p.). Thus, hourglass dolphins apparently produce clicks of higher source level, which should allow them to detect prey at more than twice the distance compared to Hector's dolphins. The observed source parameter differences within these two NBHF species may be an adaptation to a coastal cluttered environment versus a deep water, pelagic habitat.

  20. High-sensitivity monitoring of micromechanical vibration using optical whispering gallery mode resonators

    Energy Technology Data Exchange (ETDEWEB)

    Schliesser, A; Anetsberger, G; Riviere, R; Arcizet, O; Kippenberg, T J [Max-Planck-Institut fuer Quantenoptik, Hans-Kopfermann-Strasse 1, 85748 Garching (Germany)], E-mail: tjk@mpq.mpg.de

    2008-09-15

    The inherent coupling of optical and mechanical modes in high finesse optical microresonators provides a natural, highly sensitive transduction mechanism for micromechanical vibration. Using homodyne and polarization spectroscopy techniques, we achieve shot-noise limited displacement sensitivities of 10{sup -19} m Hz{sup -1/2}. In an unprecedented manner, this enables the detection and study of a variety of mechanical modes, which are identified as radial breathing, flexural and torsional modes using three-dimensional finite element modeling. Furthermore, a broadband equivalent displacement noise is measured and found to agree well with models for thermorefractive noise in silica dielectric cavities. Implications for ground-state cooling, displacement sensing and Kerr squeezing are discussed.

  1. Design and experiment of a cross-shaped mode converter for high-power microwave applications

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Shengren, E-mail: 785751053@qq.com; Yuan, Chengwei; Zhong, Huihuang; Fan, Yuwei [College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha 410073 (China)

    2013-12-15

    A compact mode converter, which is capable of converting a TM{sub 01} mode into a circularly polarized TE{sub 11} mode, was developed and experimentally studied with high-power microwaves. The converter, consisting of two turnstile junctions, is very short along the wave propagation direction, and therefore is suitable for designing compact and axially aligned high-power microwave radiation systems. In this paper, the principle of a converter working at 1.75 GHz is demonstrated, as well as the experimental results. The experimental and simulation results are in good agreement. At the center frequency, the conversion efficiency is more than 95%, the measured axial ratio is about 0.4 dB, and the power-handing capacity is excess of 1.9 GW.

  2. Design and experiment of a cross-shaped mode converter for high-power microwave applications

    Science.gov (United States)

    Peng, Shengren; Yuan, Chengwei; Zhong, Huihuang; Fan, Yuwei

    2013-12-01

    A compact mode converter, which is capable of converting a TM01 mode into a circularly polarized TE11 mode, was developed and experimentally studied with high-power microwaves. The converter, consisting of two turnstile junctions, is very short along the wave propagation direction, and therefore is suitable for designing compact and axially aligned high-power microwave radiation systems. In this paper, the principle of a converter working at 1.75 GHz is demonstrated, as well as the experimental results. The experimental and simulation results are in good agreement. At the center frequency, the conversion efficiency is more than 95%, the measured axial ratio is about 0.4 dB, and the power-handing capacity is excess of 1.9 GW.

  3. First-principles study on the high-pressure behavior of the zone-center modes of lonsdaleite silicon

    Science.gov (United States)

    Wu, B. R.

    2000-01-01

    Using a first-principles method, I have studied the static and vibrational properties of the lonsdaleite-silicon. The frequencies of the Raman active modes of the lonsdaleite-Si at ambient pressure agree very well with the experimental results. Among these Raman active modes, the E2g mode can be an indication mode of the lonsdaleite-Si. The high-pressure behavior of the zone-center modes of the lonsdaleite-Si is first studied and a pressure-induced mode softening is found. The E2u mode of the lonsdaleite-Si exhibits red shift under compression and its frequency decreases to zero as the applied pressure increases to around 14 GPa. The pressure-induced mode softening of the E2u mode indicates that the lonsdaleite-Si has a phase transition before the applied pressure reaches 14 GPa.

  4. Usual Modes of Marijuana Consumption Among High School Students in Colorado.

    Science.gov (United States)

    Johnson, Renee M; Brooks-Russell, Ashley; Ma, Ming; Fairman, Brian J; Tolliver, Rickey L; Levinson, Arnold H

    2016-07-01

    The purpose of this study was to assess the prevalence of modes of marijuana consumption among Colorado youth and explore variation by demographics, access, substance use, and risk perceptions. Data are from a 2013 survey of Colorado high school students (N = 25,197; 50.5% female). The outcome variable was usual mode of marijuana consumption (i.e., smoking, vaporizing, ingesting edibles, or other) among those reporting past 30-day marijuana use. Classification variables included sex, grade level, race/ethnicity, sexual orientation, current alcohol and cigarette use, frequent marijuana use, early marijuana use (students who use marijuana report that they usually use a mode of consumption other than smoking. Among students reporting past 30-day marijuana use, 85% said smoking was their usual mode of consumption. The remainder reported that their usual mode of consumption was vaporizing (6%), ingesting edibles (5%), or another method (4%). Boys, Whites, Asians, and 12th graders were the most likely to report vaporizing. High perceived harmfulness was associated with vaporizing or ingesting edibles. The majority of Colorado youth who use marijuana usually smoke it. Youth may be using vaporizers and ingesting edibles as a way to reduce the harm associated with inhaling combusted smoke.

  5. Design, simulation, and experimental results of a 110 GHz high-power gyrotron mode converter

    Energy Technology Data Exchange (ETDEWEB)

    Denison, D.R.; Blank, M.; Chu, T.S.; Hogge, J.P.; Kreischer, K.E.; Temkin, R.J. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Plasma Fusion Center; Harper, B.; Lorbeck, J.A.; Vernon, R.J. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Plasma Fusion Center]|[Univ. of Wisconsin, Madison, WI (United States)

    1996-12-31

    The authors present the design, computer simulation, and experimental results of a quasi-optical mode converter for use in a 110 GHz high-power gyrotron. The particular gyrotron under test generates a right-handed TE{sub 22.6} circular waveguide mode, and is designed to produce megawatt power levels over pulse durations on the order of 5s. This high power level provides a rigorous constraint on the output-beam shape; namely, that the peaking factor be approximately 2.0. Such a peaking factor corresponds to a nearly flat power distribution across the output window to allow for proper cooling of the window. To that end, the mode converter employs a rippled-wall waveguide mode transformer/beam launcher, and a pair of toroidal focusing mirrors to produce a Gaussian-like beam. Two shaping mirrors follow, and convert the Gaussian beam into a quasi-optical beam with a flat power distribution. The rippled-wall launcher was designed using standard coupled mode theory, and the toroidal mirrors derive from Gaussian beam analysis. The shaping mirrors result from a vector diffraction synthesis procedure developed at UW.

  6. Failure modes of large surface avalanche photo diodes in high-energy physics environments

    Science.gov (United States)

    Anzivino, G.; Bai, J.; Bencheikh, B.; Contin, A.; DeSalvo, R.; Fagen, S.; He, H.; Liu, L.; Lundin, M.; Madden, R. M.; Mondardini, M. R.; Szawlowski, M.; Wang, K.; Xia, X.; Yang, C.; Zhao, M.

    1999-06-01

    Large area avalanche photo diodes (APD), a new and very promising type of light detector, were tested at high gain on a beam line and suddenly failed. A detailed study of the failure modes showed that these devices, if used at low gain and with special care, may actually be used in high-energy physics environments and indicates the road of development toward radiation hard, large area APDs. No problem was found when APDs are operated in absence of highly ionizing particles.

  7. A 20 Mfps high frame-depth CMOS burst-mode imager with low power in-pixel NMOS-only passive amplifier

    Science.gov (United States)

    Wu, L.; San Segundo Bello, D.; Coppejans, P.; Craninckx, J.; Wambacq, P.; Borremans, J.

    2017-02-01

    This paper presents a 20 Mfps 32 × 84 pixels CMOS burst-mode imager featuring high frame depth with a passive in-pixel amplifier. Compared to the CCD alternatives, CMOS burst-mode imagers are attractive for their low power consumption and integration of circuitry such as ADCs. Due to storage capacitor size and its noise limitations, CMOS burst-mode imagers usually suffer from a lower frame depth than CCD implementations. In order to capture fast transitions over a longer time span, an in-pixel CDS technique has been adopted to reduce the required memory cells for each frame by half. Moreover, integrated with in-pixel CDS, an in-pixel NMOS-only passive amplifier alleviates the kTC noise requirements of the memory bank allowing the usage of smaller capacitors. Specifically, a dense 108-cell MOS memory bank (10fF/cell) has been implemented inside a 30μm pitch pixel, with an area of 25 × 30μm2 occupied by the memory bank. There is an improvement of about 4x in terms of frame depth per pixel area by applying in-pixel CDS and amplification. With the amplifier's gain of 3.3, an FD input-referred RMS noise of 1mV is achieved at 20 Mfps operation. While the amplification is done without burning DC current, including the pixel source follower biasing, the full pixel consumes 10μA at 3.3V supply voltage at full speed. The chip has been fabricated in imec's 130nm CMOS CIS technology.

  8. A hierarchy of high-order theories for modes in an elastic layer

    DEFF Research Database (Denmark)

    Sorokin, Sergey V.; Chapman, C. John

    2015-01-01

    A hierarchy of high-order theories for symmetric and skew-symmetric modes in an infinitely long elastic layer of the constant thickness is derived. For each member of the hierarchy, boundary conditions for layers of the finite length are formulated. The forcing problems at several approximation...

  9. Low-jitter and high-power 40 GHz all-active mode-locked lasers

    DEFF Research Database (Denmark)

    Yvind, Kresten; Larsson, David; Christiansen, Lotte Jin

    2004-01-01

    A novel design strategy for the epitaxial structure of monolithic mode-locked semiconductor lasers is presented. Using an all-active design, we fabricate 40-GHz lasers generating 2.8-ps almost chirp-free pulses with record low high-frequency jitter and more than 7-mW fiber coupled output power....

  10. High Performance Large Mode-Area Ytterbium-doped Photonic Crystal Fiber for Fiber Lasers

    Energy Technology Data Exchange (ETDEWEB)

    Chen Wei; Lu Peixiang [Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074 (China); Li Shiyu; Wang Dongxiang, E-mail: chenwei@fiberhome.com.cn [State Key Laboratory of Optical Communication Technologies and Networks, Fiberhome Telecommunication Technologies Co. Ltd, 430074 (China)

    2011-02-01

    In this letter, large-mode-area double-cladding ytterbium-doped photonic crystal fiber was designed in theory and fabricated in practice. This fiber we have fabricated successfully has endless single mode operation performance and large inner-cladding numerical aperture of more than 0.75. The struts width between large air-holes in the outer-cladding is about 0.22 {mu}m. The photonic crystal fiber has a mode-area about 1465.7{mu}m{sup 2}. Due to the material being pure silica and air, such structures have excellent capacity to with-stand high temperature. The laser light can have very good beam quality, even diffraction-limited beam quality because of the single-mode core. This fabrication technical breakthrough of novelty high performance double-cladding ytterbium-doped photonic crystal fibers will give contributions to the high power fiber lasers and promote the progress of technology in the fields of high power lasers.

  11. Senior High School Students' Preference and Reasoning Modes about Nuclear Energy Use.

    Science.gov (United States)

    Yang, Fang-Ying; Anderson, O. Roger

    2003-01-01

    Examines senior high school students' cognitive orientation toward scientific or social information, designated as information preference, and associated preferential reasoning modes when presented with an environmental issue concerning nuclear energy usage. Investigates the association of information preference variable with academic and personal…

  12. Theoretical and experimental study of high-Q resonant modes in terahertz optical systems

    NARCIS (Netherlands)

    Jellema, Willem; Withington, S.; Trappe, Neil; Murphy, J. A.; Wild, Wolfgang

    2004-01-01

    The existence of multiple reflections in terahertz optical system causes numerous problems in applications ranging from astronomical to medical instrumentation. We have performed a detailed theoretical study, using waveguide and free-space modal matching, of the high-Q modes that appear on THz

  13. Structural integrity and potential failure modes of hanford high-level waste tanks

    Energy Technology Data Exchange (ETDEWEB)

    Han, F.C.

    1996-09-30

    Structural Integrity of the Hanford High-Level Waste Tanks were evaluated based on the existing Design and Analysis Documents. All tank structures were found adequate for the normal operating and seismic loads. Potential failure modes of the tanks were assessed by engineering interpretation and extrapolation of the existing engineering documents.

  14. Pitch Strength as an Outcome Measure for Treatment of Dysphonia.

    Science.gov (United States)

    Kopf, Lisa M; Jackson-Menaldi, Cristina; Rubin, Adam D; Skeffington, Jean; Hunter, Eric J; Skowronski, Mark D; Shrivastav, Rahul

    2017-03-16

    Measurement of treatment outcomes is critical for the spectrum of voice treatments (ie, surgical, behavioral, or pharmacological). Outcome measures typically include visual (eg, stroboscopic data), auditory (eg, Consensus Auditory-Perceptual Evaluation of Voice; Grade, Roughness, Breathiness, Asthenia, Strain), and objective correlates of vocal fold vibratory characteristics, such as acoustic signals (eg, harmonics-to-noise ratio, cepstral peak prominence) or patient self-reported questionnaires (eg, Voice Handicap Index, Voice-Related Quality of Life). Subjective measures often show high variability, whereas most acoustic measures of voice are only valid for signals where some degree of periodicity can be assumed. However, this assumption is often invalid for dysphonic voices where signal periodicity is suspect. Furthermore, many of these measures are not useful in isolation for diagnostic purposes. We evaluated a recently developed algorithm (Auditory Sawtooth Waveform Inspired Pitch Estimator-Prime [Auditory-SWIPE']) for estimating pitch and pitch strength for dysphonic voices. Whereas fundamental frequency is a physical attribute of a signal, pitch is its psychophysical correlate. As such, the perception of pitch can extend to most signals irrespective of their periodicity. Post hoc analyses were conducted for three groups of patients evaluated and treated for voice problems at a major voice center: (1) muscle tension dysphonia/functional dysphonia, (2) vocal fold mass(es), and (3) presbyphonia. All patients were recorded before and after surgical/behavioral treatment for voice disorders. Pitch and pitch strength for each speaker were computed with the Auditory-SWIPE' algorithm. Comparison of pre- and posttreatment data provides support for pitch strength as a measure of treatment outcomes for dysphonic voices. Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

  15. Renal stone characterization using high resolution imaging mode on a photon counting detector CT system

    Science.gov (United States)

    Ferrero, A.; Gutjahr, R.; Henning, A.; Kappler, S.; Halaweish, A.; Abdurakhimova, D.; Peterson, Z.; Montoya, J.; Leng, S.; McCollough, C.

    2017-03-01

    In addition to the standard-resolution (SR) acquisition mode, a high-resolution (HR) mode is available on a research photon-counting-detector (PCD) whole-body CT system. In the HR mode each detector consists of a 2x2 array of 0.225 mm x 0.225 mm subpixel elements. This is in contrast to the SR mode that consists of a 4x4 array of the same subelements, and results in 0.25 mm isotropic resolution at iso-center for the HR mode. In this study, we quantified ex vivo the capabilities of the HR mode to characterize renal stones in terms of morphology and mineral composition. Forty pure stones - 10 uric acid (UA), 10 cystine (CYS), 10 calcium oxalate monohydrate (COM) and 10 apatite (APA) - and 14 mixed stones were placed in a 20 cm water phantom and scanned in HR mode, at radiation dose matched to that of routine dual-energy stone exams. Data from micro CT provided a reference for the quantification of morphology and mineral composition of the mixed stones. The area under the ROC curve was 1.0 for discriminating UA from CYS, 0.89 for CYS vs COM and 0.84 for COM vs APA. The root mean square error (RMSE) of the percent UA in mixed stones was 11.0% with a medium-sharp kernel and 15.6% with the sharpest kernel. The HR showed qualitatively accurate characterization of stone morphology relative to micro CT.

  16. Digital control of high-frequency switched-mode power converters

    CERN Document Server

    Corradini, Luca; Mattavelli, Paolo; Zane, Regan

    This book is focused on the fundamental aspects of analysis, modeling and design of digital control loops around high-frequency switched-mode power converters in a systematic and rigorous manner Comprehensive treatment of digital control theory for power converters Verilog and VHDL sample codes are provided Enables readers to successfully analyze, model, design, and implement voltage, current, or multi-loop digital feedback loops around switched-mode power converters Practical examples are used throughout the book to illustrate applications of the techniques developed Matlab examples are also

  17. Characterization of coal- and petroleum-derived binder pitches and the interaction of pitch/coke mixtures in pre-baked carbon anodes

    Science.gov (United States)

    Suriyapraphadilok, Uthaiporn

    Carbon anodes are manufactured from calcined petroleum coke (i.e. sponge coke) and recycled anode butts as fillers, and coal tar pitch (SCTP) as the binder. During the manufacturing of carbon anodes, coal tar pitch is mixed with calcined petroleum coke. The mix of binder, filler and some additives is heated to about 50°C above the softening point of the pitch, typically 160°C. This temperature is sufficient to enable the pitch to wet the coke particles. The mix is then either extruded, vibrated, or pressed to form a green anode. The binding between coke and pitch is very important to the anode properties. There are different binder pitches used in this work, which were standard coal tar pitch (SCTP-2), petroleum pitch (PP-1), gasification pitch (GP-115), coal-extract pitch (WVU-5), and co-coking pitches (HTCCP and OXCCP). Petroleum pitch is a residue produced from heat-treatment and distillation of petroleum fractions. Production of coal-extract pitch involves a prehydrogenation of coal followed by extraction using a dipolar solvent. Gasification pitches are distilled by-product tars produced from the coal gasification process. Co-coking pitch was developed in this work and was obtained from the liquid distillate of co-coking process of coal and heavy petroleum residue. Understanding of composition and structures of pitches from different sources and processes would lead to greater understanding of the binding properties of pitch in carbon anodes and was one of the main focuses in this study. Characterization of pitches by using different techniques including gas chromatography/mass spectrometry (GC/MS), high performance liquid chromatography (HPLC), matrix-assisted laser desorption ionization/mass spectrometry (MALDI/MS), 1H and 13C solution-state nuclear magnetic resonance (NMR), and 13C solid-state NMR yield important chemistry and structural information. The binding, or in other words the interactions in the pitch/coke mixture, is another interest in this

  18. Ultra-high pitch chest computed tomography at 70 kVp tube voltage in an anthropomorphic pediatric phantom and non-sedated pediatric patients. Initial experience with 3{sup rd} generation dual-source CT

    Energy Technology Data Exchange (ETDEWEB)

    Hagelstein, Claudia; Henzler, Thomas; Haubenreisser, Holger; Meyer, Mathias; Sudarski, Sonja; Schoenberg, Stefan O.; Neff, K. Wolfgang; Weis, Meike [Univ. Medical Center Mannheim (Germany). Inst. of Clinical Radiology and Nuclear Medicine

    2016-07-01

    Minimizing radiation dose while at the same time preserving image quality is of particular importance in pediatric chest CT. Very recently, CT imaging with a tube voltage of 70 kVp has become clinically available. However, image noise is inversely proportional to the tube voltage. We aimed to investigate radiation dose and image quality of pediatric chest CT performed at 70 kVp in an anthropomorphic pediatric phantom as well as in clinical patients. An anthropomorphic pediatric phantom, which resembles a one-year-old child in physiognomy, was scanned on the 3{sup rd} generation dual-source CT (DSCT) system at 70 kVp and 80 kVp and a fixed ultra low tube-current of 8 mAs to solely evaluate the impact of lowering tube voltage. After the phantom measurements, 18 pediatric patients (mean 29.5 months; range 1-91 months; 21 examinations) underwent 3.2 high-pitch chest CT on the same DSCT system at 70 kVp tube voltage without any sedation. Radiation dose and presence of motion artifacts was compared to a retrospectively identified patient cohort examined at 80 kVp on a 16-slice single-source-CT (SSCT; n = 15; 14/15 with sedation; mean 30.7 months; range 0-96 months; pitch = 1.5) or on a 2{sup nd} generation DSCT without any sedation (n = 6; mean 32.8 months; range 4-61 months; pitch = 3.2). Radiation dose in the phantom scans was reduced by approximately 40% when using a tube voltage of 70 kVp instead of 80 kVp. In the pediatric patient group examined at 70 kVp age-specific effective dose (ED; mean 0.5 ± 0.2 mSv) was significantly lower when compared to the retrospective cohort scanned at 80 kVp on the 16-slice-SSCT (mean ED: 1.0 ± 0.3 mSv; p < 0.0001) and also considerably lower when compared to the cohort scanned at 80 kVp on the 2{sup nd} generation DSCT (mean ED: 0.9 ± 0.5 mSv). None of the prospective, sedation-free CT examinations showed any motion artifacts whereas 13/15 examinations of the retrospective patient cohort scanned at 80 kVp with a pitch of 1

  19. Ultra-high pitch chest computed tomography at 70 kVp tube voltage in an anthropomorphic pediatric phantom and non-sedated pediatric patients: Initial experience with 3(rd) generation dual-source CT.

    Science.gov (United States)

    Hagelstein, Claudia; Henzler, Thomas; Haubenreisser, Holger; Meyer, Mathias; Sudarski, Sonja; Schoenberg, Stefan O; Neff, K Wolfgang; Weis, Meike

    2016-12-01

    Minimizing radiation dose while at the same time preserving image quality is of particular importance in pediatric chest CT. Very recently, CT imaging with a tube voltage of 70 kVp has become clinically available. However, image noise is inversely proportional to the tube voltage. We aimed to investigate radiation dose and image quality of pediatric chest CT performed at 70 kVp in an anthropomorphic pediatric phantom as well as in clinical patients. An anthropomorphic pediatric phantom, which resembles a one-year-old child in physiognomy, was scanned on the 3(rd) generation dual-source CT (DSCT) system at 70 kVp and 80 kVp and a fixed ultra low tube-current of 8 mAs to solely evaluate the impact of lowering tube voltage. After the phantom measurements, 18 pediatric patients (mean 29.5 months; range 1-91 months; 21 examinations) underwent 3.2 high-pitch chest CT on the same DSCT system at 70 kVp tube voltage without any sedation. Radiation dose and presence of motion artifacts was compared to a retrospectively identified patient cohort examined at 80 kVp on a 16-slice single-source-CT (SSCT; n=15; 14/15 with sedation; mean 30.7 months; range 0-96 months; pitch=1.5) or on a 2(nd) generation DSCT without any sedation (n=6; mean 32.8 months; range 4-61 months; pitch=3.2). Radiation dose in the phantom scans was reduced by approximately 40% when using a tube voltage of 70 kVp instead of 80 kVp. In the pediatric patient group examined at 70 kVp age-specific effective dose (ED; mean 0.5±0.2 mSv) was significantly lower when compared to the retrospective cohort scanned at 80 kVp on the 16-slice-SSCT (mean ED: 1.0±0.3 mSv; p<0.0001) and also considerably lower when compared to the cohort scanned at 80 kVp on the 2(nd) generation DSCT (mean ED: 0.9±0.5 mSv). None of the prospective, sedation-free CT examinations showed any motion artifacts whereas 13/15 examinations of the retrospective patient cohort scanned at 80 kVp with a pitch of 1.5 showed motion artifacts. 3.2 high-pitch

  20. A 20 GHz, high efficiency dual mode TWT for the ACTS program. [Advanced Communications Technology Satellite

    Science.gov (United States)

    Muennemann, Frank; Dombro, Louis; Long, Jin

    1986-01-01

    The development of a 50 W/10 W dual mode K-band downlink TWT is examined, and its performance is evaluated. The designs of the electron gun, RF circuit, and collector for the TWT, which is enclosed in a capsule, are described. It is observed that the high power mode (HPM) power output is at 50 GHz and the low power mode (LPM) output is at 12 GHz; the saturated gain is 52.5 dB for HPM and 3 dB for LPM; the AM-PM is 4.2 dB; the HPM dc power output is 104 W; and the LPM dc output is 42 W; and the efficiency is 45 percent for the HPM and 28.6 percent for the LPM.

  1. High order sliding mode control of a DFIM supplied by two power inverters

    Directory of Open Access Journals (Sweden)

    Zinelaabidine Boudjema

    2015-06-01

    Full Text Available Traditional vector control structures which include proportional-integral (PI regulator for the speed of a doubly fed induction motor (DFIM driven have some disadvantages such as parameter tuning complications, mediocre dynamic performances and reduced robustness. Thus, based on the analysis of the mathematical model of a DFIM supplied by two indirect inverters, this paper addresses a nonlinear control algorithm based on high order sliding mode. The conventional sliding mode control has large chattering on the electromagnetic torque developed by the DFIM. In order to solve this problem, the second order sliding mode technique is used. The simulation results show the effectiveness of the proposed method especially in chattering-free behavior, response to sudden load torque variations and robustness against machine parameters variations.

  2. Drift stabilization of ballooning modes in a high-langβrang LHD configuration

    Science.gov (United States)

    Brocher, L.; Cooper, W. A.; Graves, J. P.; Cooper, G. A.; Narushima, Y.; Watanabe, K. Y.

    2010-02-01

    Ideal MHD yields at best inconclusive predictions about the stability of the LHD heliotron for langβrang >= 3%. We investigate the impact of the drift stabilization of ballooning modes for the inward-shifted LHD configuration (vacuum magnetic axis R0 ~ 3.5 m). The background equilibrium is considered anisotropic in which the neutral beam ions contribute about 1/4 fraction of the total diamagnetic beta, langβdiarang. A drift corrected ballooning mode equation obtained from the linearized gyrokinetic equation is expanded assuming that the hot particle drifts are much larger than the mode frequency. The fast particle pressure gradients contribute weakly to both the instability drive and the diamagnetic drift stabilization (which is dominated by the thermal ion diamagnetic drifts) for langβdiarang in [0, 4.8]%. In the single-fluid limit (diamagnetic drifts ignored), the thermal pressure gradients drive ballooning modes in a broad region encompassing the outer 60-90% of the plasma volume at langβdiarang ≈ 4.8%. To stabilize these modes, we find that diamagnetic drift corrections must be invoked (mainly due to the thermal ions). The energetic ion diamagnetic drifts play a role only for low wave number values, kα <= 8. It has been verified that the fast particle drift ordering imposed by the model is amply satisfied for on-axis hot particle to thermal density Nh0/Ni0 ≈ 1% even at high langβdiarang.

  3. Anticipated Degradation Modes of Metallic Engineered Barriers for High-Level Nuclear Waste Repositories

    Science.gov (United States)

    Rodríguez, Martín A.

    2014-03-01

    Metallic engineered barriers must provide a period of absolute containment to high-level radioactive waste in geological repositories. Candidate materials include copper alloys, carbon steels, stainless steels, nickel alloys, and titanium alloys. The national programs of nuclear waste management have to identify and assess the anticipated degradation modes of the selected materials in the corresponding repository environment, which evolves in time. Commonly assessed degradation modes include general corrosion, localized corrosion, stress-corrosion cracking, hydrogen-assisted cracking, and microbiologically influenced corrosion. Laboratory testing and modeling in metallurgical and environmental conditions of similar and higher aggressiveness than those expected in service conditions are used to evaluate the corrosion resistance of the materials. This review focuses on the anticipated degradation modes of the selected or reference materials as corrosion-resistant barriers in nuclear repositories. These degradation modes depend not only on the selected alloy but also on the near-field environment. The evolution of the near-field environment varies for saturated and unsaturated repositories considering backfilled and unbackfilled conditions. In saturated repositories, localized corrosion and stress-corrosion cracking may occur in the initial aerobic stage, while general corrosion and hydrogen-assisted cracking are the main degradation modes in the anaerobic stage. Unsaturated repositories would provide an oxidizing environment during the entire repository lifetime. Microbiologically influenced corrosion may be avoided or minimized by selecting an appropriate backfill material. Radiation effects are negligible provided that a thick-walled container or an inner shielding container is used.

  4. [Preliminary study of individualized contrast injection protocols in triple-rule-out computed tomography angiography using a high-pitch dual-source technique].

    Science.gov (United States)

    Li, Jinyan; Zhang, Guowei; Wang, Ximing; Duan, Yanhua; Ji, Xiaopeng; Cao, Ting; Sun, Wenyue; Qi, Yaodong

    2015-08-04

    To assess the feasibility of individual contrast injection protocols in triple-rule-out computed tomography examination using a dual-source Flash-chest-pain technique. From April to August 2014, 63 patients with undifferentiated acute chest pain underwent ECG-synchronized dual-spiral chest CT angiography. 31 Patients, who all had low (individual triphasic contrast protocol based on weight (350 mgI/ml, A: 0.7 ml/kg, setting 10 s duration time; B: 8 s mixture of the contrast agent and saline at the same rate; C: 6-7 s saline at the same rate). In contrast, the other patients, who had random heart rate, underwent TRO CT angiography in a traditional retrospectively mode with an identical biphasic contrast protocol (350 mgI/ml, A: contrast agent 90 ml, B: saline 40 ml, injection rate 5 ml/s). Quantitative image analysis assessed vessel attenuation of aorta, coronary and pulmonary artery, signal-to-noise ratio (SNR) and contrast-to noise ratio (CNR). Subjective image was assessed on a 5 point scale (1: excellent, 5:non-diagnosis) by two blind observers. The effective dose was calculated from the dose length product (DLP) using a conversion coefficient of 0.017 mSv·mGy(-1)·cm(-1). There was no significant difference of aorta and coronary artery attenuation, noise, SNR, CNR or subjective image quality between both patient groups. Pulmonary artery attenuation was lower in test group than in control group, but it also can meet the diagnostic criteria. Moreover, the mean contrast agent and the effective dose were lower in test group than in control group (72±10) vs (90±0) ml, Pindividual contrast protocol along with dual-source high-pith technique, is capable of achieving satisfactory image which could meet the diagnostic requirements with lower contrast agent and lower effective dose.

  5. Reliable Fluid Power Pitch Systems

    DEFF Research Database (Denmark)

    Liniger, Jesper; Pedersen, Henrik Clemmensen; Soltani, Mohsen

    2015-01-01

    The key objectives of wind turbine manufactures and buyers are to reduce the Total Cost of Ownership and Total Cost of Energy. Among others, low downtime of a wind turbine is important to increase the amount of energy produced during its lifetime. Historical data indicate that pitch systems accou...

  6. Beethoven's Last Piano Sonata and Those Who Follow Crocodiles: Cross-Domain Mappings of Auditory Pitch in a Musical Context

    Science.gov (United States)

    Eitan, Zohar; Timmers, Renee

    2010-01-01

    Though auditory pitch is customarily mapped in Western cultures onto spatial verticality (high-low), both anthropological reports and cognitive studies suggest that pitch may be mapped onto a wide variety of other domains. We collected a total number of 35 pitch mappings and investigated in four experiments how these mappings are used and…

  7. High frequency switched-mode stimulation can evoke postsynaptic responses in cerebellar principal neurons

    Directory of Open Access Journals (Sweden)

    Marijn Van Dongen

    2015-03-01

    Full Text Available This paper investigates the efficacy of high frequency switched-mode neural stimulation. Instead of using a constant stimulation amplitude, the stimulus is switched on and off repeatedly with a high frequency (up to 100kHz duty cycled signal. By means of tissue modeling that includes the dynamic properties of both the tissue material as well as the axon membrane, it is first shown that switched-mode stimulation depolarizes the cell membrane in a similar way as classical constant amplitude stimulation.These findings are subsequently verified using in vitro experiments in which the response of a Purkinje cell is measured due to a stimulation signal in the molecular layer of the cerebellum of a mouse. For this purpose a stimulator circuit is developed that is able to produce a monophasic high frequency switched-mode stimulation signal. The results confirm the modeling by showing that switched-mode stimulation is able to induce similar responses in the Purkinje cell as classical stimulation using a constant current source. This conclusion opens up possibilities for novel stimulation designs that can improve the performance of the stimulator circuitry. Care has to be taken to avoid losses in the system due to the higher operating frequency.

  8. Absolute Pitch Twin Study and Segregation Analysis

    National Research Council Canada - National Science Library

    Theusch, Elizabeth; Gitschier, Jane

    2011-01-01

    Absolute pitch is a rare pitch-naming ability with unknown etiology. Some scientists maintain that its manifestation depends solely on environmental factors, while others suggest that genetic factors contribute...

  9. First-principles method for high-$Q$ photonic crystal cavity mode calculations

    CERN Document Server

    Mahmoodian, Sahand; Poulton, Christopher G; Dossou, Kokou B; Botten, Lindsay C; McPhedran, Ross C; de Sterke, C Martijn

    2012-01-01

    We present a first-principles theory to compute radiation properties of ultra-high quality factor photonic crystal (PC) cavities using a basis of bound PC waveguide states. This method is used to compute the far-field radiation pattern and quality factor of cavity modes $\\sim 100$ times more rapidly than conventional finite-difference time domain methods. Our method provides a simple rule for engineering the PC cavity far-field radiation pattern in high $Q$ cavities.

  10. VAMOS: A variable mode high acceptance spectrometer for identifying reaction products induced by SPIRAL beams

    CERN Document Server

    Savajols, H

    2003-01-01

    The study of reactions induced by the SPIRAL beams at GANIL requires new techniques: the low intensity of secondary beams implies the need of a very high efficiency detection system; the study of nearly or completely unknown nuclei, over a wide range of masses and energies, needs a very efficient method for attributing a reaction product to a nucleus. The variable mode high acceptance spectrometer VAMOS is being designed and built especially for this purpose.

  11. The Significance of the Right Dorsolateral Prefrontal Cortex for Pitch Memory in Non-musicians Depends on Baseline Pitch Memory Abilities

    Directory of Open Access Journals (Sweden)

    Nora K. Schaal

    2017-12-01

    Full Text Available Pitch memory is a resource which is shared by music and language. Neuroimaging studies have shown that the right dorsolateral prefrontal cortex (DLPFC is activated during pitch memory processes. The present study investigated the causal significance of this brain area for pitch memory in non-musicians by applying cathodal and sham transcranial direct current stimulation (tDCS over the right DLPFC and examining the impact on offline pitch and visual memory span performances. On the overall sample (N = 22 no significant modulation effect of cathodal stimulation on the pitch span task was found. However, when dividing the sample by means of a median split of pre-test pitch memory abilities into a high and low performing group, a selective effect of significantly impaired pitch memory after cathodal tDCS in good performers was revealed. The visual control task was not affected by the stimulation in either group. The results support previous neuroimaging studies that the right DLPFC is involved in pitch memory processes in non-musicians and highlights the importance of baseline pitch memory abilities for the modulatory effect of tDCS.

  12. The Significance of the Right Dorsolateral Prefrontal Cortex for Pitch Memory in Non-musicians Depends on Baseline Pitch Memory Abilities.

    Science.gov (United States)

    Schaal, Nora K; Kretschmer, Marina; Keitel, Ariane; Krause, Vanessa; Pfeifer, Jasmin; Pollok, Bettina

    2017-01-01

    Pitch memory is a resource which is shared by music and language. Neuroimaging studies have shown that the right dorsolateral prefrontal cortex (DLPFC) is activated during pitch memory processes. The present study investigated the causal significance of this brain area for pitch memory in non-musicians by applying cathodal and sham transcranial direct current stimulation (tDCS) over the right DLPFC and examining the impact on offline pitch and visual memory span performances. On the overall sample ( N = 22) no significant modulation effect of cathodal stimulation on the pitch span task was found. However, when dividing the sample by means of a median split of pre-test pitch memory abilities into a high and low performing group, a selective effect of significantly impaired pitch memory after cathodal tDCS in good performers was revealed. The visual control task was not affected by the stimulation in either group. The results support previous neuroimaging studies that the right DLPFC is involved in pitch memory processes in non-musicians and highlights the importance of baseline pitch memory abilities for the modulatory effect of tDCS.

  13. Transformasi Pitch Suara Manusia Menggunakan Metode PSOLA

    Directory of Open Access Journals (Sweden)

    SUSETYO BAGAS BHASKORO

    2016-02-01

    Full Text Available Abstrak Kemampuan pengubahan suara yang dilakukan Dubber untuk beragam bentuk suara menjadi perhatian khusus dengan melakukan rekayasa suara, di dalam perkembangan teknologi di kenal sebuah teknikpitch shifting yang digunakan untuk mengubah suara manusia di bagian timbre dan pitch. Penelitian ini menggunakan metodepitch shifting PSOLA (Pitch Synchronous Overlap Add untuk merubah pitch sekaligus timbre suara. Proses yang dilakukan meliputi perekaman suara sehingga didapatkan sinyal suara. Sinyal hasil perekaman kemudian diolah untuk menemukan posisi pitch dari sinyal pada domain waktu. Setelah posisi pitch diketahui, jarak antar pitch akan dikalikan dengan bilangan skala pergeseran yang sudah ditentukan. Hasil dari perkalian tersebut adalah perubahan pada pitch suara, sehingga menghasilkan suara yang lebih tinggi atau lebih rendah. Perubahan juga terjadi pada timbre sehingga menghasilkan karakter suara yang berbeda dengan suara aselinya.Hasil pengujian pitch dan timbre dengan menggunakan metode PSOLA menunjukkan keberhasilan mencapai 98% berdasarkan sinyal sinus. Kata kunci: Pitch, Timbre,Pitch Shifting, PSOLA. Abstract The ability of converts sound done in various forms of a dubber sound, becomes a special attention in doing an engineering design sound. In the development of technology the pitch of shifting know a technique that is used to turn the human voice in the timbre and  pitch. This study using methods  pitch  shifting psola (pitch synchronous overlap add to change the pitch as well as the timbre sound. The process was about recording a sound so obtained up a noise. Recording signals then processed the results to find the position of the pitch signals on the domain of time. After the position of the pitch known, the distance between the pitch will be multiplied by the number of the scale of a shift that had been determined. The result of the multiplication of the sound is a change in pitch , so producing a higher or lower, Also

  14. Encoding pitch contours using current steering

    OpenAIRE

    Luo, Xin; Landsberger, David M.; Padilla, Monica; Srinivasan, Arthi G.

    2010-01-01

    This study investigated cochlear implant (CI) users’ ability to perceive pitch cues from time-varying virtual channels (VCs) to identify pitch contours. Seven CI users were tested on apical, medial, and basal electrode pairs with stimulus durations from 100 to 1000 ms. In one stimulus set, 9 pitch contours were created by steering current between the component electrodes and the VC halfway between the electrodes. Another stimulus set only contained 3 pitch contours (flat, falling, and rising)...

  15. Low Vocal Pitch Preference Drives First Impressions Irrespective of Context in Male Voices but Not in Female Voices.

    Science.gov (United States)

    Tsantani, Maria S; Belin, Pascal; Paterson, Helena M; McAleer, Phil

    2016-08-01

    Vocal pitch has been found to influence judgments of perceived trustworthiness and dominance from a novel voice. However, the majority of findings arise from using only male voices and in context-specific scenarios. In two experiments, we first explore the influence of average vocal pitch on first-impression judgments of perceived trustworthiness and dominance, before establishing the existence of an overall preference for high or low pitch across genders. In Experiment 1, pairs of high- and low-pitched temporally reversed recordings of male and female vocal utterances were presented in a two-alternative forced-choice task. Results revealed a tendency to select the low-pitched voice over the high-pitched voice as more trustworthy, for both genders, and more dominant, for male voices only. Experiment 2 tested an overall preference for low-pitched voices, and whether judgments were modulated by speech content, using forward and reversed speech to manipulate context. Results revealed an overall preference for low pitch, irrespective of direction of speech, in male voices only. No such overall preference was found for female voices. We propose that an overall preference for low pitch is a default prior in male voices irrespective of context, whereas pitch preferences in female voices are more context- and situation-dependent. The present study confirms the important role of vocal pitch in the formation of first-impression personality judgments and advances understanding of the impact of context on pitch preferences across genders.

  16. Avoidance High-Frequency Chattering Second-Order Sliding Mode Controller Design: Buck Converter in Wind Power System

    Directory of Open Access Journals (Sweden)

    Yigeng Huangfu

    2012-01-01

    Full Text Available This paper mainly discussed a method of high-frequency second-order sliding mode control for Buck converter in wind power systems. Because the wind energy of nature is always unpredictable and intermittent, the robust control such as sliding mode control is adopted in past literatures. In order to remove the high frequency chattering problem when the traditional sliding mode achieves convergence, the second order sliding mode algorithm is reviewed firstly. Meanwhile, the Buck converter taken as a step-down converter is usually adopted in wind power system, because of its simple structure and good linearity. Under those conditions, the second order sliding mode controller is designed based on Buck converter, especially in high-power wind generation system. The experimental results illustrate that the theory of second order sliding mode can be used in high-power Buck converter. It provides one novel avoidance high frequency chattering method for the technology development of new energy generation system.

  17. Trophic mode conversion and nitrogen deprivation of microalgae for high ammonium removal from synthetic wastewater.

    Science.gov (United States)

    Wang, Jinghan; Zhou, Wenguang; Yang, Haizhen; Wang, Feng; Ruan, Roger

    2015-11-01

    In this study, a well-controlled three-stage process was proposed for high ammonium removal from synthetic wastewater using selected promising microalgal strain UMN266. Three trophic modes (photoautotrophy, heterotrophy, and mixotrophy), two N sufficiency conditions (N sufficient and N deprived), two inoculum modes (photoautotrophic and heterotrophic), and different NH4(+)-N concentrations were compared to investigate the effect of trophic mode conversion and N deprivation on high NH4(+)-N removal by UMN266. Results showed that photoautotrophic inoculum with trophic mode conversion from heterotrophy to photoautotrophy and N deprivation in Stage 2 turned was the optimum plan for NH4(+)-N removal, and average removal rates were 12.4 and 19.1mg/L/d with initial NH4(+)-N of 80 and 160mg/L in Stage 3. Mechanism investigations based on algal biomass carbon (C) and N content, cellular composition, and starch content confirmed the above optimum plan and potential of UMN266 as bioethanol feedstock. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. High-Q lattice mode matched structural resonances in terahertz metasurfaces

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Ningning; Zhang, Weili, E-mail: weili.zhang@okstate.edu [School of Electrical and Computer Engineering, Oklahoma State University, Stillwater, Oklahoma 74078 (United States); Singh, Ranjan, E-mail: ranjans@ntu.edu.sg [Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371 (Singapore); Centre for Disruptive Photonic Technologies, The Photonics Institute, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore)

    2016-07-11

    The quality (Q) factor of metamaterial resonances is limited by the radiative and non-radiative losses. At terahertz frequencies, the dominant loss channel is radiative in nature since the non-radiative losses are low due to high conductivity of metals. Radiative losses could be suppressed by engineering the meta-atom structure. However, such suppression usually occurs at the fundamental resonance mode which is typically a closed mode resonance such as an inductive-capacitive resonance or a Fano resonance. Here, we report an order of magnitude enhancement in Q factor of all the structural eigenresonances of a split-ring resonator fueled by the lattice mode matching. We match the fundamental order diffractive mode to each of the odd and even eigenresonances, thus leading to a tremendous line-narrowing of all the resonances. Such precise tailoring and control of the structural resonances in a metasurface lattice could have potential applications in low-loss devices, sensing, and design of high-Q metamaterial cavities.

  19. Shoulder and Scapular Kinematics during the Windmill Softball Pitch

    Science.gov (United States)

    Backus, Sherry I.; Kraszewski, Andrew; Kontaxis, Andreas; Gibbons, Mandi; Bido, Jennifer; Graziano, Jessica; Hafer, Jocelyn; Jones, Kristofer J.; Hillstrom, Howard; Fealy, Stephen

    2013-01-01

    Objectives: Pitch count has been studied extensively in the overhand throwing athlete. However, pitch count and fatigue have not been systematically evaluated in the female windmill (underhand) throwing athlete. Direct kinematic measurements of the glenohumeral and scapulo-thoracic joint have not to be correlated and determined. The purpose is to measure scapular kinematics for the high school female windmill softball pitcher and identify kinematic adaptions and changes in pitching performance due to fatigue. Methods: Eight female high school softball pitchers without previous shoulder injury were enrolled. Three-dimensional (3D) motion of the humerus, scapula and trunk were recorded with surface markers at 250 Hz. Marker placement and the anatomical calibration of bony landmarks followed recommendations by the ISB (Wu et al. 2005) and Kontaxis et al (2009). A custom marker cluster was used to dynamically track the scapula (Karduna et al. 2001). The pitching mound was at regulation distance (43’) from the strike zone target. All athletes completed 105 pitches in sets of 15 with a rest of 5 minutes between sets. Ball speed recorded with a radar gun, 3D angular rotations of the glenohumeral joint, scapulo-thoracic joint and thorax with respect to the room were calculated for all throws. The last five pitches of every set were averaged for analysis. Results: Ball speed (Figure 1, n=8 subjects) and peak glenohumeral, scapulo-thoracic and thoracic angular rotations (n=4 subjects) were consistent across all sets. Examples of kinematics at two of these joints are presented across all sets (Figure 2, n=4). Data across all planes demonstrated similar consistency. Conclusion: This study presents a systematic protocol for the study of fatigue during windmill softball pitching. To our knowledge, this is one of the first studies to analyze glenohumeral as well as scapulo-thoracic kinematics during this task. The consistency in the glenohumeral, scapulo-thoracic and torso

  20. Normal-Hearing Listeners’ and Cochlear Implant Users’ Perception of Pitch Cues in Emotional Speech

    Directory of Open Access Journals (Sweden)

    Steven Gilbers

    2015-10-01

    Full Text Available In cochlear implants (CIs, acoustic speech cues, especially for pitch, are delivered in a degraded form. This study’s aim is to assess whether due to degraded pitch cues, normal-hearing listeners and CI users employ different perceptual strategies to recognize vocal emotions, and, if so, how these differ. Voice actors were recorded pronouncing a nonce word in four different emotions: anger, sadness, joy, and relief. These recordings’ pitch cues were phonetically analyzed. The recordings were used to test 20 normal-hearing listeners’ and 20 CI users’ emotion recognition. In congruence with previous studies, high-arousal emotions had a higher mean pitch, wider pitch range, and more dominant pitches than low-arousal emotions. Regarding pitch, speakers did not differentiate emotions based on valence but on arousal. Normal-hearing listeners outperformed CI users in emotion recognition, even when presented with CI simulated stimuli. However, only normal-hearing listeners recognized one particular actor’s emotions worse than the other actors’. The groups behaved differently when presented with similar input, showing that they had to employ differing strategies. Considering the respective speaker’s deviating pronunciation, it appears that for normal-hearing listeners, mean pitch is a more salient cue than pitch range, whereas CI users are biased toward pitch range cues.

  1. Design of short high-power TE11-HE11 mode converters in highly overmoded corrugated waveguides

    Science.gov (United States)

    Thumm, Manfred; Jacobs, Annemarie; Sorolla Ayza, Mario

    1991-02-01

    A theoretical parametric study of TE11 to HE11 mode conversion in highly oversized, circumferentially corrugated circular waveguides with different inner diameters is presented for various frequencies in the range of 28 to 140 GHz. The depth of the annular slots is tapered gradually from one half to one quarter wavelength. Computer-aided optimization of converter length, shape of corrugations, and nonlinear slot depth variation has been achieved with a scattering matrix code employing the modal field matching techniques (modular analysis concept). Relatively short mode transducers with matched converter lengths are feasible. The optimum conversion lengths are L1 roughly 0.5 lambda(B) (short converter) and L2 roughly 1.2 lambda(B) (long converter), where lambda(B) is the beat wavelength of the TE11 and TM11 modes in the corresponding smooth-walled circular waveguide. The predicted performances of short and long mode transducers are practically identical. Experimental results taken at 70 GHz are in excellent agreement with the theoretically predicted performance data. In all cases the HE11 output mode purity is 99 percent to 99.5 percent. The maximum cross-polarization and input-reflection levels are below -29 dB and -50 dB, respectively.

  2. Investigation of polyvinylidene fluoride (PVDF) films in identifying high-frequency vibration modes of flexible plates.

    Science.gov (United States)

    Chuang, Kuo-Chih; Liou, Hong-Cin; Ma, Chien-Ching

    2014-06-01

    Compared with piezoelectric ceramics such as lead zirconate titanate (PZT) ceramics, the low density and high compliance of the PVDF films make them a more suitable choice in modal testing, especially for detecting high-frequency modes in flexible or inflatable structures. In this work, dynamic sensing performances of PVDF films for flexible structures in modal testing are examined, with considerations including the repeatability of the impact source, the accuracy of the sensing responses, and the influences of the nodal lines on the frequency spectra of the transient responses. Two flexible plates with different boundary conditions and thickness are considered. Experimental results, compared with FEM computations or theoretical predictions, demonstrate the excellent dynamic sensing performance of the PVDF film in modal testing applications, especially for identification of high-frequency modes on flexible structures.

  3. High-order harmonic generation from polyatomic molecules including nuclear motion and a nuclear modes analysis

    DEFF Research Database (Denmark)

    Madsen, Christian Bruun; Abu-Samha, Mahmoud; Madsen, Lars Bojer

    2010-01-01

    as a nuclear correlation function. We express the nuclear correlation function in terms of Franck-Condon factors, which allows us to decompose nuclear motion into modes and identify the modes that are dominant in the high-order harmonic generation process. We show results for the isotopes CH4 and CD4......We present a generic approach for treating the effect of nuclear motion in high-order harmonic generation from polyatomic molecules. Our procedure relies on a separation of nuclear and electron dynamics where we account for the electronic part using the Lewenstein model and nuclear motion enters...... and thereby provide direct theoretical support for a recent experiment [S. Baker et al., Science 312, 424 (2006)] that uses high-order harmonic generation to probe the ultrafast structural nuclear rearrangement of ionized methane....

  4. High Energy, Single-Mode, All-Solid-State and Tunable UV Laser Transmitter

    Science.gov (United States)

    Prasad, Narasimha S.; Singh, Upendra N.; Hovis, FLoyd

    2007-01-01

    A high energy, single mode, all solid-state Nd:YAG laser primarily for pumping an UV converter is developed. Greater than 1 J/pulse at 50 HZ PRF and pulse widths around 22 ns have been demonstrated. Higher energy, greater efficiency may be possible. Refinements are known and practical to implement. Technology Demonstration of a highly efficient, high-pulse-energy, single mode UV wavelength generation using flash lamp pumped laser has been achieved. Greater than 90% pump depletion is observed. 190 mJ extra-cavity SFG; IR to UV efficiency > 21% (> 27% for 1 mJ seed). 160 mJ intra-cavity SFG; IR to UV efficiency up to 24% Fluence laser is being refined to match or exceed the above UV converter results. Currently the Nd:YAG pump laser development is a technology demonstration. System can be engineered for compact packaging.

  5. From tone to pitch in Sepedi

    CSIR Research Space (South Africa)

    Barnard, E

    2010-05-01

    Full Text Available " or "low". Automatic pitch extraction was then used to estimate the fundamental frequencies of the voiced segments of each of these syllables. Statistical analysis of the resulting pitch contours confirms that the mean pitch frequencies of the syllabic...

  6. Cross-Cultural Perspectives on Pitch Memory

    Science.gov (United States)

    Trehub, Sandra E.; Schellenberg, E. Glenn; Nakata, Takayuki

    2008-01-01

    We examined effects of age and culture on children's memory for the pitch level of familiar music. Canadian 9- and 10-year-olds distinguished the original pitch level of familiar television theme songs from foils that were pitch-shifted by one semitone, whereas 5- to 8-year-olds failed to do so (Experiment 1). In contrast, Japanese 5- and…

  7. Design of a high power TM01 mode launcher optimized for manufacturing by milling

    Energy Technology Data Exchange (ETDEWEB)

    Dal Forno, Massimo [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2016-12-15

    Recent research on high-gradient rf acceleration found that hard metals, such as hard copper and hard copper-silver, have lower breakdown rate than soft metals. Traditional high-gradient accelerating structures are manufactured with parts joined by high-temperature brazing. The high temperature used in brazing makes the metal soft; therefore, this process cannot be used to manufacture structures out of hard metal alloys. In order to build the structure with hard metals, the components must be designed for joining without high-temperature brazing. One method is to build the accelerating structures out of two halves, and join them by using a low-temperature technique, at the symmetry plane along the beam axis. The structure has input and output rf power couplers. We use a TM01 mode launcher as a rf power coupler, which was introduced during the Next Linear Collider (NLC) work. The part of the mode launcher will be built in each half of the structure. This paper presents a novel geometry of a mode launcher, optimized for manufacturing by milling. The coupler was designed for the CERN CLIC working frequency f = 11.9942 GHz; the same geometry can be scaled to any other frequency.

  8. Combustion Mode Design with High Efficiency and Low Emissions Controlled by Mixtures Stratification and Fuel Reactivity

    Directory of Open Access Journals (Sweden)

    Hu eWang

    2015-08-01

    Full Text Available This paper presents a review on the combustion mode design with high efficiency and low emissions controlled by fuel reactivity and mixture stratification that have been conducted in the authors’ group, including the charge reactivity controlled homogeneous charge compression ignition (HCCI combustion, stratification controlled premixed charge compression ignition (PCCI combustion, and dual-fuel combustion concepts controlled by both fuel reactivity and mixture stratification. The review starts with the charge reactivity controlled HCCI combustion, and the works on HCCI fuelled with both high cetane number fuels, such as DME and n-heptane, and high octane number fuels, such as methanol, natural gas, gasoline and mixtures of gasoline/alcohols, are reviewed and discussed. Since single fuel cannot meet the reactivity requirements under different loads to control the combustion process, the studies related to concentration stratification and dual-fuel charge reactivity controlled HCCI combustion are then presented, which have been shown to have the potential to achieve effective combustion control. The efforts of using both mixture and thermal stratifications to achieve the auto-ignition and combustion control are also discussed. Thereafter, both charge reactivity and mixture stratification are then applied to control the combustion process. The potential and capability of thermal-atmosphere controlled compound combustion mode and dual-fuel reactivity controlled compression ignition (RCCI/highly premixed charge combustion (HPCC mode to achieve clean and high efficiency combustion are then presented and discussed. Based on these results and discussions, combustion mode design with high efficiency and low emissions controlled by fuel reactivity and mixtures stratification in the whole operating range is proposed.

  9. Single Longitudinal Mode, High Repetition Rate, Q-switched Ho:YLF Laser for Remote Sensing

    Science.gov (United States)

    Bai, Yingxin; Yu, Jirong; Petzar, Paul; Petros, M.; Chen, Songsheng; Trieu, Bo; Lee, Nyung; Singh, U.

    2009-01-01

    Ho:YLF/LuLiF lasers have specific applications for remote sensing such as wind-speed measurement and carbon dioxide (CO2) concentration measurement in the atmosphere because the operating wavelength (around 2 m) is located in the eye-safe range and can be tuned to the characteristic lines of CO2 absorption and there is strong backward scattering signal from aerosol (Mie scattering). Experimentally, a diode pumped Ho:Tm:YLF laser has been successfully used as the transmitter of coherent differential absorption lidar for the measurement of with a repetition rate of 5 Hz and pulse energy of 75 mJ [1]. For highly precise CO2 measurements with coherent detection technique, a laser with high repetition rate is required to averaging out the speckle effect [2]. In addition, laser efficiency is critically important for the air/space borne lidar applications, because of the limited power supply. A diode pumped Ho:Tm:YLF laser is difficult to efficiently operate in high repetition rate due to the large heat loading and up-conversion. However, a Tm:fiber laser pumped Ho:YLF laser with low heat loading can be operated at high repetition rates efficiently [3]. No matter whether wind-speed or carbon dioxide (CO2) concentration measurement is the goal, a Ho:YLF/LuLiF laser as the transmitter should operate in a single longitudinal mode. Injection seeding is a valid technique for a Q-switched laser to obtain single longitudinal mode operation. In this paper, we will report the new results for a single longitudinal mode, high repetition rate, Q-switched Ho:YLF laser. In order to avoid spectral hole burning and make injection seeding easier, a four mirror ring cavity is designed for single longitudinal mode, high repetition rate Q-switched Ho:YLF laser. The ramp-fire technique is chosen for injection seeding.

  10. Pitch and Plasticity: Insights from the Pitch Matching of Chords by Musicians with Absolute and Relative Pitch

    Directory of Open Access Journals (Sweden)

    Neil M. McLachlan

    2013-12-01

    Full Text Available Absolute pitch (AP is a form of sound recognition in which musical note names are associated with discrete musical pitch categories. The accuracy of pitch matching by non-AP musicians for chords has recently been shown to depend on stimulus familiarity, pointing to a role of spectral recognition mechanisms in the early stages of pitch processing. Here we show that pitch matching accuracy by AP musicians was also dependent on their familiarity with the chord stimulus. This suggests that the pitch matching abilities of both AP and non-AP musicians for concurrently presented pitches are dependent on initial recognition of the chord. The dual mechanism model of pitch perception previously proposed by the authors suggests that spectral processing associated with sound recognition primes waveform processing to extract stimulus periodicity and refine pitch perception. The findings presented in this paper are consistent with the dual mechanism model of pitch, and in the case of AP musicians, the formation of nominal pitch categories based on both spectral and periodicity information.

  11. Neural mechanisms underlying melodic perception and memory for pitch.

    Science.gov (United States)

    Zatorre, R J; Evans, A C; Meyer, E

    1994-04-01

    The neural correlates of music perception were studied by measuring cerebral blood flow (CBF) changes with positron emission tomography (PET). Twelve volunteers were scanned using the bolus water method under four separate conditions: (1) listening to a sequence of noise bursts, (2) listening to unfamiliar tonal melodies, (3) comparing the pitch of the first two notes of the same set of melodies, and (4) comparing the pitch of the first and last notes of the melodies. The latter two conditions were designed to investigate short-term pitch retention under low or high memory load, respectively. Subtraction of the obtained PET images, superimposed on matched MRI scans, provides anatomical localization of CBF changes associated with specific cognitive functions. Listening to melodies, relative to acoustically matched noise sequences, resulted in CBF increases in the right superior temporal and right occipital cortices. Pitch judgments of the first two notes of each melody, relative to passive listening to the same stimuli, resulted in right frontal-lobe activation. Analysis of the high memory load condition relative to passive listening revealed the participation of a number of cortical and subcortical regions, notably in the right frontal and right temporal lobes, as well as in parietal and insular cortex. Both pitch judgment conditions also revealed CBF decreases within the left primary auditory cortex. We conclude that specialized neural systems in the right superior temporal cortex participate in perceptual analysis of melodies; pitch comparisons are effected via a neural network that includes right prefrontal cortex, but active retention of pitch involves the interaction of right temporal and frontal cortices.

  12. High-Energy Four-Wave Mixing, with Large-Mode-Area Higher-Order Modes in Optical Fibres

    DEFF Research Database (Denmark)

    Rishøj, Lars Søgaard; Steinvurzel, P. E.; Chen, Y.

    2012-01-01

    We demonstrate, for the first time, four-wave mixing, in the 1-μm spectral regime, in an LMA silica fiber. Pumping a 618-μm2 LP07 mode (λo = 1038.4 nm) with a 1064.6-nm Nd:YAG laser results in the generation of modulation instability, and multiple Stokes/anti-Stokes lines, opening up the prospect...

  13. Biconical-taper-assisted fiber interferometer with modes coupling enhancement for high-sensitive curvature measurement

    Science.gov (United States)

    Wo, Jianghai; Sun, Qizhen; Li, Xiaolei; Liu, Deming; Shum, Perry Ping

    2014-04-01

    A modal interferometer based on multimode-singlemode-multimode fiber structure built with a biconical taper for fiber curvature measurement is proposed and experimentally demonstrated. Due to the tapered singlemode fiber acting as a high-efficient mode power converter to enhance the modes coupling, curvature sensor with improved sensitivity is achieved by monitoring the defined fringe visibility of the interference spectrum. The measuring range can be tuned by changing the waist diameter of the fiber taper. Meanwhile, the sensor shows an intrinsic ability to overcome the influence of temperature cross-sensitivity and the power fluctuation of light source. The advantages of easy fabrication, high-quality spectrum with improved sensitivity, and small hysteresis will provide great potential for practical applications of the sensor.

  14. Review of self-focusing of high power lasers in large-mode-area optical fibers

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Chujun; Li Ying; Lei Dajun; Yang Hua; Wen Shuangchun; Fan Dianyuan; Wen Jianguo, E-mail: scwen@vip.sina.com [Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education, School of Computer and Communication, Hunan University, Changsha 410082 (China)

    2011-02-01

    The main progress about the self-focusing of high power lasers in large-mode-area optical fiber has been reviewed. The theoretical models including the self-focusing effects have been discussed. Some different views on the whole beam self focusing and small scale self-focusing effects in optical fiber have been introduced. Moreover, the possible methods exceeding the bulk-media self-focusing threshold have been discussed and explored.

  15. High efficiency Yb3+-doped phosphate single-mode fibre laser

    Science.gov (United States)

    Franczyk, M.; Stępień, R.; Piechal, B.; Pysz, D.; Stawicki, K.; Siwicki, B.; Buczyński, R.

    2017-10-01

    We report on a ytterbium-doped phosphate glass single-mode fibre laser, 4 cm long, with a maximum output power of 11.6 W and a slope efficiency of 66.6%. We developed the double-clad fibre with a 19 µm diameter step-index core and a pump waveguide with a high numerical aperture due to external air-cladding. The estimated pump absorption in the fibre exceeded 700 dB m-1.

  16. Amorphous selenium direct detection CMOS digital x-ray imager with 25 micron pixel pitch

    Science.gov (United States)

    Scott, Christopher C.; Abbaszadeh, Shiva; Ghanbarzadeh, Sina; Allan, Gary; Farrier, Michael; Cunningham, Ian A.; Karim, Karim S.

    2014-03-01

    We have developed a high resolution amorphous selenium (a-Se) direct detection imager using a large-area compatible back-end fabrication process on top of a CMOS active pixel sensor having 25 micron pixel pitch. Integration of a-Se with CMOS technology requires overcoming CMOS/a-Se interfacial strain, which initiates nucleation of crystalline selenium and results in high detector dark currents. A CMOS-compatible polyimide buffer layer was used to planarize the backplane and provide a low stress and thermally stable surface for a-Se. The buffer layer inhibits crystallization and provides detector stability that is not only a performance factor but also critical for favorable long term cost-benefit considerations in the application of CMOS digital x-ray imagers in medical practice. The detector structure is comprised of a polyimide (PI) buffer layer, the a-Se layer, and a gold (Au) top electrode. The PI layer is applied by spin-coating and is patterned using dry etching to open the backplane bond pads for wire bonding. Thermal evaporation is used to deposit the a-Se and Au layers, and the detector is operated in hole collection mode (i.e. a positive bias on the Au top electrode). High resolution a-Se diagnostic systems typically use 70 to 100 μm pixel pitch and have a pre-sampling modulation transfer function (MTF) that is significantly limited by the pixel aperture. Our results confirm that, for a densely integrated 25 μm pixel pitch CMOS array, the MTF approaches the fundamental material limit, i.e. where the MTF begins to be limited by the a-Se material properties and not the pixel aperture. Preliminary images demonstrating high spatial resolution have been obtained from a frst prototype imager.

  17. High-resolution measurement of differential mode delay of few-mode fiber using phase reference technique for swept-frequency interferometry

    Science.gov (United States)

    Ohno, Shingo; Iida, Daisuke; Toge, Kunihiro; Manabe, Tetsuya

    2018-01-01

    A method is described for the high-resolution measurement of the differential mode delay (DMD) of few-mode fiber based on the frequency-modulated continuous wave (FMCW) technique. With the conventional approach, a wider optical bandwidth is required for higher resolution, however, the effect of chromatic dispersion becomes critical and limits the actual resolution. This paper proposes and demonstrates a phase reference technique for FMCW signals that achieves high-resolution measurements without increasing the optical bandwidth. We can also further improve the resolution of our proposed method by reducing the phase fluctuation with signal averaging. The feasibility of the proposed method is confirmed experimentally with several kinds of FMFs including an offset-spliced fiber where mode couplings occur.

  18. All-optical tunable buffering with coupled ultra-high Q whispering gallery mode microcavities.

    Science.gov (United States)

    Yoshiki, Wataru; Honda, Yoshihiro; Tetsumoto, Tomohiro; Furusawa, Kentaro; Sekine, Norihiko; Tanabe, Takasumi

    2017-09-06

    All-optical tunable buffering was recently achieved on a chip by using dynamically tuned coupled mode induced transparency, which is an optical analogue of electromagnetically induced transparency. However, the small Q s of about 105 used in those systems were limiting the maximum buffering time to a few hundred ps. Although employing an ultra-high Q whispering gallery mode (WGM) microcavity can significantly improve the maximum buffering time, the dynamic tuning of the WGM has remained challenging because thermo-optic and pressure tunings, which are widely used for WGM microcavities, have a very slow response. Here we demonstrate all-optical tunable buffering utilizing coupled ultra-high Q WGM cavities and the Kerr effect. The Kerr effect can change the refractive index instantaneously, and this allowed us to tune the WGM cavity very quickly. In addition, from among the various WGM cavities we employed a silica toroid microcavity for our experiments because it has an ultra-high Q factor (>2 × 107) and a small mode volume, and can be fabricated on a chip. Use of the Kerr effect and the silica toroid microcavity enabled us to observe an on-chip all-optical tunable buffering operation and achieve a maximum buffering time of 20 ns.

  19. Aerodynamic control with passively pitching wings

    Science.gov (United States)

    Gravish, Nick; Wood, Robert

    Flapping wings may pitch passively under aerodynamic and inertial loads. Such passive pitching is observed in flapping wing insect and robot flight. The effect of passive wing pitch on the control dynamics of flapping wing flight are unexplored. Here we demonstrate in simulation and experiment the critical role wing pitching plays in yaw control of a flapping wing robot. We study yaw torque generation by a flapping wing allowed to passively rotate in the pitch axis through a rotational spring. Yaw torque is generated through alternating fast and slow upstroke and and downstroke. Yaw torque sensitively depends on both the rotational spring force law and spring stiffness, and at a critical spring stiffness a bifurcation in the yaw torque control relationship occurs. Simulation and experiment reveal the dynamics of this bifurcation and demonstrate that anomalous yaw torque from passively pitching wings is the result of aerodynamic and inertial coupling between the pitching and stroke-plane dynamics.

  20. Glenohumeral rotational motion and strength and baseball pitching biomechanics.

    Science.gov (United States)

    Hurd, Wendy J; Kaufman, Kenton R

    2012-01-01

    Addressing loss of shoulder range of motion and rotator cuff weakness in injury-prevention programs might be an effective strategy for preventing throwing arm injuries in baseball pitchers. However, the influence of these clinical measures on pitching biomechanics is unclear. To evaluate the relationships among clinical measures of shoulder rotational motion and strength and 3-dimensional pitching biomechanics and to evaluate the presence of coupling between the shoulder and the elbow during pitching to provide insight into the influence of clinical shoulder characteristics on elbow biomechanics. Cross-sectional study. Biomechanics laboratory. A total of 27 uninjured male high school baseball pitchers (age = 16 ± 1.1 years, height = 183 ± 7 cm, mass = 83 ± 12 kg). Clinical measures included shoulder internal- and external-rotation range of motion and peak isometric internal- and external-rotator strength. Three-dimensional upper extremity biomechanics were assessed as participants threw from an indoor pitching mound to a target at regulation distance. Linear regressions were used to assess the influence of clinical measures on the peak shoulder internal and external rotation moments and the peak elbow-adduction moment. We found a positive relationship between clinically measured internal-rotator strength and shoulder external-rotation moment (R(2) = 0.181, P = .04) during pitching. We also noted an inverse relationship between clinically measured external-rotation motion and the elbow-adduction moment (R(2) = 0.160, P = .04) and shoulder internal-rotation moment (R(2) = 0.250, P = .008) during pitching. We found a positive relationship between peak shoulder internal-rotation moment and the peak elbow-adduction moment (R(2) = 0.815, P biomechanics and how these clinical measures might contribute to throwing arm injuries in the baseball pitcher. A relationship also was identified between peak shoulder and elbow moments in the throwing arm during pitching

  1. Perceiving pitch absolutely: Comparing absolute and relative pitch possessors in a pitch memory task

    Directory of Open Access Journals (Sweden)

    Schlaug Gottfried

    2009-08-01

    Full Text Available Abstract Background The perceptual-cognitive mechanisms and neural correlates of Absolute Pitch (AP are not fully understood. The aim of this fMRI study was to examine the neural network underlying AP using a pitch memory experiment and contrasting two groups of musicians with each other, those that have AP and those that do not. Results We found a common activation pattern for both groups that included the superior temporal gyrus (STG extending into the adjacent superior temporal sulcus (STS, the inferior parietal lobule (IPL extending into the adjacent intraparietal sulcus (IPS, the posterior part of the inferior frontal gyrus (IFG, the pre-supplementary motor area (pre-SMA, and superior lateral cerebellar regions. Significant between-group differences were seen in the left STS during the early encoding phase of the pitch memory task (more activation in AP musicians and in the right superior parietal lobule (SPL/intraparietal sulcus (IPS during the early perceptual phase (ITP 0–3 and later working memory/multimodal encoding phase of the pitch memory task (more activation in non-AP musicians. Non-significant between-group trends were seen in the posterior IFG (more in AP musicians and the IPL (more anterior activations in the non-AP group and more posterior activations in the AP group. Conclusion Since the increased activation of the left STS in AP musicians was observed during the early perceptual encoding phase and since the STS has been shown to be involved in categorization tasks, its activation might suggest that AP musicians involve categorization regions in tonal tasks. The increased activation of the right SPL/IPS in non-AP musicians indicates either an increased use of regions that are part of a tonal working memory (WM network, or the use of a multimodal encoding strategy such as the utilization of a visual-spatial mapping scheme (i.e., imagining notes on a staff or using a spatial coding for their relative pitch height for pitch

  2. Design of a High Performance Green-Mode PWM Controller IC with Smart Sensing Protection Circuits

    Directory of Open Access Journals (Sweden)

    Shen-Li Chen

    2014-08-01

    Full Text Available A design of high performance green-mode pulse-width-modulation (PWM controller IC with smart sensing protection circuits for the application of lithium-ion battery charger (1.52 V ~ 7.5 V is investigated in this paper. The protection circuits architecture of this system mainly bases on the lithium battery function and does for the system design standard of control circuit. In this work, the PWM controller will be with an automatic load sensing and judges the system operated in the operating mode or in the standby mode. Therefore, it reduces system’s power dissipation effectively and achieves the saving power target. In the same time, many protection sensing circuits such as: (1 over current protection (OCP and under current protection (UCP, (2 over voltage protection (OVP and under voltage protection (UVP, (3 loading determintion and short circuit protection (SCP, (4 over temperature protection (OTP, (5 VDD surge-spiking protection are included. Then, it has the characteristics of an effective monitoring the output loading and the harm prevention as a battery charging. Eventually, this green-mode pulse-width-modulation (PWM controller IC will be that the operation voltage is 3.3 V, the operation frequency is 0.98 MHz, and the output current range is from 454 mA to 500 mA. Meanwhile, the output convert efficiency is range from 74.8 % to 91 %, the power dissipation efficiency in green-mode is 25 %, and the operation temperature range is between -20 0C ~ 114 0C.

  3. Effects of excitation around jet preferred mode Strouhal number in high-speed jets

    Science.gov (United States)

    Kuo, Ching-Wen; Cluts, Jordan; Samimy, Mo

    2017-04-01

    It has been widely reported in the literature that the jet preferred mode Strouhal number varies over a large range of 0.2-0.6, depending upon the facility where the measurement is made as well as the measurement techniques and the location in the jet plume where the measurement is taken. This study investigates this wide variation and potential explanations for it. Active flow control is used to show that the jet is receptive to excitation over a large range of Strouhal numbers and azimuthal modes. The wide variation in the preferred mode Strouhal number is shown to be tightly linked to the evolution, spacing, and scale of the coherent flow structures, which dominate the jet shear layer's development. The low-end of the range is determined by the minimum Strouhal number at which structures begin to interact with one another in the jet plume. Below this range, structures have no significant effect on the plume's statistical properties. For Strouhal numbers at the high-end of the range, the development of coherent flow structures shifts upstream toward the nozzle exit and the structures disintegrate earlier in the jet plume. The earlier development and disintegration prevent these structures from strongly impacting the entire flowfield. The results imply that upstream perturbations in the flow present in various facilities could be responsible for the variations in the measured jet preferred mode Strouhal number. Experimental results from schlieren imaging and near- and far-field microphone measurements are used to investigate the preferred mode Strouhal number across this range.

  4. Dynamics of fluidic devices with applications to rotor pitch links

    Science.gov (United States)

    Scarborough, Lloyd H., III

    impedance. At low frequency, the pitch link must have high impedance to pass through the pilot's collective and cyclic commands to control the aircraft. At higher frequencies, however, the pitch-link impedance can be tuned to change the blade pitching response to higher harmonic loads. Active blade control to produce higher harmonic pitch motions has been shown to reduce hub loads and increase rotor efficiency. This work investigates whether fluidic pitch links can passively provide these benefits. An analytical model of a fluidic pitch link is derived and incorporated into a rotor aeroelastic simulation for a rotor similar to that of the UH-60. Eighty-one simulations with varied fluidic pitch link parameters demonstrate that their impedance can be tailored to reduce rotor power and all six hub forces and moments. While no impedance was found that simultaneously reduced all components, the results include cases with reductions in the lateral 4/rev hub force of up to 91% and 4/rev hub pitching moment of up to 67%, and main rotor power of up to 5%.

  5. Photonic crystal nanofiber air-mode cavity with high Q-factor and high sensitivity for refractive index sensing

    Science.gov (United States)

    Ma, Xiaoxue; Chen, Xin; Nie, Hongrui; Yang, Daquan

    2018-01-01

    Recently, due to its superior characteristics and simple manufacture, such as small size, low loss, high sensitivity and convenience to couple, the optical fiber sensor has become one of the most promising sensors. In order to achieve the most effective realization of light propagation by changing the structure of sensors, FOM(S •Q/λres) ,which is determined by two significant variables Q-factor and sensitivity, as a trade-off parameter should be optimized to a high value. In typical sensors, a high Q can be achieved by confining the optical field in the high refractive index dielectric region to make an interaction between analytes and evanescent field of the resonant mode. However, the ignored sensitivity is relatively low with a high Q achieved, which means that the resonant wavelength shift changes non-obviously when the refractive index increases. Meanwhile, the sensitivity also leads to a less desirable FOM. Therefore, a gradient structure, which can enhance the performance of sensors by achieving high Q and high sensitivity, has been developed by Kim et al. later. Here, by introducing parabolic-tapered structure, the light field localized overlaps strongly and sufficiently with analytes. And based on a one-dimensional photonic-crystal nanofiber air-mode cavity, a creative optical fiber sensor is proposed by combining good stability and transmission characteristics of fiber and strengths of tapered structure, realizing excellent FOM {4.7 x 105 with high Q-factors (Q{106) and high sensitivities (<700 nm/RIU).

  6. Biceps activity during windmill softball pitching: injury implications and comparison with overhand throwing.

    Science.gov (United States)

    Rojas, Idubijes L; Provencher, Matthew T; Bhatia, Sanjeev; Foucher, Kharma C; Bach, Bernard R; Romeo, Anthony A; Wimmer, Markus A; Verma, Nikhil N

    2009-03-01

    Windmill pitching produces high forces and torques at the shoulder and elbow, making the biceps labrum complex susceptible to overuse injury. Little is known about the muscle firing patterns during a windmill pitch. Biceps muscle activity is greater during a windmill pitch than during an overhand throw. Descriptive laboratory study. Seven female windmill pitchers underwent motion analysis and surface electromyography evaluation of their biceps muscles during windmill and overhand throwing. Marker motion analysis, muscle activity, and ball release were captured simultaneously. Surface electromyography trials were collected and related to the athletes' phases of pitching and throwing, identified based on predefined softball and baseball pitching mechanics. Throws were of similar velocity (24 m/s, 53 mph, P = .71), but peak biceps brachii muscle activation during the windmill pitch was significantly greater than during the overhand throw when normalized (38% vs 19% manual muscle test, P = .02). The highest muscle activity occurred at the 9-o'clock phase of the windmill pitch, during which the biceps brachii undergoes eccentric contraction. In the overhand throw, the highest level of biceps activity occurred during arm cocking. In female athletes, biceps brachii activity during the windmill pitch is higher than during an overhand throw and is most active during the 9-o'clock and follow-through phases of the pitch. Repetitive eccentric biceps contractions may help explain the high incidence of anterior shoulder pain clinically observed in elite windmill pitchers. Injury prevention and treatment mechanisms should focus on the phases with the highest muscle activity.

  7. Sub-20nm hybrid lithography using optical, pitch-division, and e-beam

    Science.gov (United States)

    Belledent, J.; Smayling, M.; Pradelles, J.; Pimenta-Barros, P.; Barnola, S.; Mage, L.; Icard, B.; Lapeyre, C.; Soulan, S.; Pain, L.

    2012-03-01

    A roadmap extending far beyond the current 22nm CMOS node has been presented several times. [1] This roadmap includes the use of a highly regular layout style which can be decomposed into "lines and cuts."[2] The "lines" can be done with existing optical immersion lithography and pitch division with self-aligned spacers.[3] The "cuts" can be done with either multiple exposures using immersion lithography, or a hybrid solution using either EUV or direct-write ebeam.[ 4] The choice for "cuts" will be driven by the availability of cost-effective, manufacturing-ready equipment and infrastructure. Optical lithography improvements have enabled scaling far beyond what was expected; for example, soft x-rays (aka EUV) were in the semiconductor roadmap as early as 1994 since optical resolution was not expected for sub-100nm features. However, steady improvements and innovations such as Excimer laser sources and immersion photolithography have allowed some manufacturers to build 22nm CMOS SOCs with single-exposure optical lithography. With the transition from random complex 2D shapes to regular 1D-patterns at 28nm, the "lines and cuts" approach can extend CMOS logic to at least the 7nm node. The spacer double patterning for lines and optical cuts patterning is expected to be used down to the 14nm node. In this study, we extend the scaling to 18nm half-pitch which is approximately the 10-11nm node using spacer pitch division and complementary e-beam lithography. For practical reasons, E-Beam lithography is used as well to expose the "mandrel" patterns that support the spacers. However, in a production mode, it might be cost effective to replace this step by a standard 193nm exposure and applying the spacer technique twice to divide the pitch by 3 or 4. The Metal-1 "cut" pattern is designed for a reasonably complex logic function with ~100k gates of combinatorial logic and flip-flops. Since the final conductor is defined by a Damascene process, the "cut" patterns become islands

  8. A high pressure study of the eigenvectors of the infra-red active vibrational modes of crystalline adenosine.

    Science.gov (United States)

    Starkey, Carl A; Lee, Scott A; Anderson, Anthony

    2016-01-01

    High-pressure infrared spectroscopy has been used to study the eigenvectors and eigenvalues of the vibrational modes of crystalline adenosine at 298 K by evaluating the logarithmic derivative of the vibrational frequency with respect to pressure: [Formula: see text]. Crystalline samples of molecular materials such as adenosine have vibrational modes that are localized within a molecular unit ("internal" modes) as well as modes in which the molecular units vibrate against each other ("external" modes). The value of the logarithmic derivative is that it is a diagnostic probe of the nature of the eigenvector of these vibrational modes. Stretching modes, which are predominantly internal to the molecule, have low logarithmic derivatives while external modes have higher logarithmic derivatives. Particular attention is paid to modes in the 800-1000 cm(-1) range since modes in that region of the vibrational spectrum are found to be sensitive to the conformation of double-helical DNA. Since the sugar pucker is different for the various conformations of DNA, this fact suggests that these modes involve the motion of atoms in the sugar group. The vibrations of the hydrogen atoms are also of interest to study since the vibrational frequency of hydrogen atoms involved in hydrogen bonds has a negative pressure derivative. Such behavior clearly shows which hydrogen atoms are involved in hydrogen bonding.

  9. Pulsed differential holographic measurements of vibration modes of high temperature panels

    Science.gov (United States)

    Evensen, D. A.; Aprahamian, R.; Overoye, K. R.

    1972-01-01

    Holography is a lensless imaging technique which can be applied to measure static or dynamic displacements of structures. Conventional holography cannot be readily applied to measure vibration modes of high-temperature structures, due to difficulties caused by thermal convection currents. The present report discusses the use of pulsed differential holography, which is a technique for recording structural motions in the presence of random fluctuations such as turbulence. An analysis of the differential method is presented, and demonstration experiments were conducted using heated stainless steel plates. Vibration modes were successfully recorded for the heated plates at temperatures of 1000, 1600, and 2000 F. The technique appears promising for such future measurments as vibrations of the space shuttle TPS panels or recording flutter of aeroelastic models in a wind-tunnel.

  10. High-resistance GaN epilayers with low dislocation density via growth mode modification

    Science.gov (United States)

    Xu, Z. Y.; Xu, F. J.; Wang, J. M.; Lu, L.; Yang, Z. J.; Wang, X. Q.; Shen, B.

    2016-09-01

    High-resistance GaN with low dislocation density adopting growth mode modification has been investigated by metalorganic chemical vapor deposition. The sheet resistance of the order of 1016 Ω/sq has been achieved at room temperature by diminishing the oxygen impurity level close to the substrate with an AlN blocking layer. Attributed to this method which offers more freedom to tailor the growth mode, a three-dimensional (3D) growth process is introduced by adjusting the growth pressure and temperature at the initial stage of the GaN epitaxy to improve the crystalline quality. The large 3D GaN grains formed during this period roughen the surface, and the following coalescence of the GaN grains causes threading dislocations bending, which finally remarkably reduces the dislocation density.

  11. Survey of degradation modes of candidate materials for high-level radioactive-waste disposal containers

    Energy Technology Data Exchange (ETDEWEB)

    Strum, M.J.; Weiss, H.; Farmer, J.C. (Lawrence Livermore National Lab., CA (USA)); Bullen, D.B. (Science and Engineering Associates, Inc., Pleasanton, CA (USA))

    1988-06-01

    This volume surveys the effects of welding on the degradation modes of three austenitic alloys: Types 304L and 316L stainless steels and Alloy 825. These materials are candidates for the fabrication of containers for the long-term storage of high-level nuclear waste. The metallurgical characteristics of fusion welds are reviewed here and related to potential degradation modes of the containers. Three specific areas are discussed in depth: (1) decreased resistance to corrosion in the forms of preferential corrosion, sensitization, and susceptibility to stress corrosion cracking, (2) hot cracking in the heat-affected zone and the weld zone, and (3) formation of intermetallic phases. The austenitic alloys are ranked as follows in terms of overall weldability: Alloy 825 (best) > Type 316L stainless steel > Type 304L stainless steel (worst). 108 refs., 31 figs., 7 tabs.

  12. High-frequency Born synthetic seismograms based on coupled normal modes

    Science.gov (United States)

    Pollitz, Fred F.

    2011-01-01

    High-frequency and full waveform synthetic seismograms on a 3-D laterally heterogeneous earth model are simulated using the theory of coupled normal modes. The set of coupled integral equations that describe the 3-D response are simplified into a set of uncoupled integral equations by using the Born approximation to calculate scattered wavefields and the pure-path approximation to modulate the phase of incident and scattered wavefields. This depends upon a decomposition of the aspherical structure into smooth and rough components. The uncoupled integral equations are discretized and solved in the frequency domain, and time domain results are obtained by inverse Fourier transform. Examples show the utility of the normal mode approach to synthesize the seismic wavefields resulting from interaction with a combination of rough and smooth structural heterogeneities. This approach is applied to an ∼4 Hz shallow crustal wave propagation around the site of the San Andreas Fault Observatory at Depth (SAFOD).

  13. A study and classification of non-linear high frequency ionospheric instabilities by coupled mode theory.

    Science.gov (United States)

    Harker, K. J.

    1972-01-01

    Two basic high-frequency ionospheric instabilities are discussed - i.e., the three-wave parametric interaction, and the oscillating two-stream instability. In the parametric instability, the ion-acoustic wave has a complex frequency, whereas in the oscillating two-stream instability the ion-acoustic frequency is purely imaginary. The parametric instability is shown to be the only one whose threshold depends on the ion collision frequency. A coupled-mode theory is proposed which permits study and classification of high-frequency instabilities on a unified basis.

  14. Strong Scattering of High Power Millimeter Waves in Tokamak Plasmas with Tearing Modes

    DEFF Research Database (Denmark)

    Westerhof, E.; Nielsen, Stefan Kragh; Oosterbeek, J.W.

    2009-01-01

    In tokamak plasmas with a tearing mode, strong scattering of high power millimeter waves, as used for heating and noninductive current drive, is shown to occur. This new wave scattering phenomenon is shown to be related to the passage of the O point of a magnetic island through the high power...... heating beam. The density determines the detailed phasing of the scattered radiation relative to the O-point passage. The scattering power depends strongly nonlinearly on the heating beam power. ©2009 The American Physical Society...

  15. Supplementary High-Input Impedance Voltage-Mode Universal Biquadratic Filter Using DVCCs

    Directory of Open Access Journals (Sweden)

    Jitendra Mohan

    2012-01-01

    Full Text Available To further extend the existing knowledge on voltage-mode universal biquadratic filter, in this paper, a new biquadratic filter circuit with single input and multiple outputs is proposed, employing three differential voltage current conveyors (DVCCs, three resistors, and two grounded capacitors. The proposed circuit realizes all the standard filter functions, that is, high-pass, band-pass, low-pass, notch, and all-pass filters simultaneously. The circuit enjoys the feature of high-input impedance, orthogonal control of resonance angular frequency (o, and quality factor (Q via grounded resistor and the use of grounded capacitors which is ideal for IC implementation.

  16. Comparison of high order modes damping techniques for 800 MHz single cell superconducting cavities

    CERN Document Server

    Shashkov, Ya V; Zobov, M M

    2014-01-01

    Currently, applications of 800 MHz harmonic cavities in both bunch lengthening and shortening regimes are under consideration and discussion in the framework of the High Luminosity LHC project. In this paper we study electromagnetic characteristics of high order modes (HOM) for a single cell 800 MHz superconducting cavity and arrays of such cavities connected by drifts tubes. Different techniques for the HOM damping such as beam pipe grooves, coaxial-notch loads, fluted beam pipes etc. are investigated and compared. The influence of the sizes and geometry of the drift tubes on the HOM damping is analyzed.

  17. Design of High-Voltage Switch-Mode Power Amplifier Based on Digital-Controlled Hybrid Multilevel Converter

    National Research Council Canada - National Science Library

    Hou, Yanbin; Sun, Wanrong; Ren, Aifeng; Liu, Shuming

    2016-01-01

    ...) and hybrid multilevel converter. Under the control of input signal, cascaded power converters with separate DC sources operate in PSM switch mode to directly generate high-voltage and high-power output...

  18. Reliability, failure modes, and degradation mechanisms in high power single- and multi-mode InGaAs-AlGaAs strained quantum well lasers

    Science.gov (United States)

    Sin, Yongkun; Presser, Nathan; Lingley, Zachary; Brodie, Miles; Foran, Brendan; Moss, Steven C.

    2016-03-01

    High power single-mode (SM) and multi-mode (MM) InGaAs-AlGaAs strained quantum well (QW) lasers are critical components for both telecommunications and potential space satellite communications systems. However, little has been reported on failure modes of state-of-the-art SM InGaAs-AlGaAs strained QW lasers although it is crucial to understand failure modes and underlying degradation mechanisms in developing these lasers that meet lifetime requirements for space satellite systems, where extremely high reliability of these lasers is required. Our present study addresses the aforementioned issues by performing long-term life tests under different test conditions followed by failure mode analysis (FMA) and physics of failure investigation. We performed long-term accelerated life-tests on state-of-the-art SM and MM InGaAs-AlGaAs strained QW lasers under ACC (automatic current control) mode. Our life-tests have accumulated over 25,000 test hours for SM lasers and over 35,000 test hours for MM lasers. FMA was performed on failed SM lasers using electron beam induced current (EBIC). This technique allowed us to identify failure types by observing dark line defects. All the SM failures we studied showed catastrophic and sudden degradation and all of these failures were bulk failures. Our group previously reported that bulk failure or COBD (catastrophic optical bulk damage) is the dominant failure mode of MM InGaAs-AlGaAs strained QW lasers. To the best of our knowledge, this is the first report demonstrating that the dominant failure mode of both SM and MM InGaAs-AlGaAs strained QW lasers is the bulk failure. Since degradation mechanisms responsible for COBD are still not well understood, we also employed other techniques including focused ion beam (FIB) processing and high-resolution TEM to further study dark line defects and dislocations in post-aged SM and MM lasers. Our long-term life test results and FMA results are reported.

  19. Children’s identification of familiar songs from pitch and timing cues

    Directory of Open Access Journals (Sweden)

    Anna eVolkova

    2014-08-01

    Full Text Available The goal of the present study was to ascertain whether children with normal hearing and prelingually deaf children with cochlear implants could use pitch or timing cues alone or in combination to identify familiar songs. Children 4-7 years of age were required to identify the theme songs of familiar TV shows in a simple task with excerpts that preserved (1 the relative pitch and timing cues of the melody but not the original instrumentation, (2 the timing cues only (rhythm, meter, and tempo, and (3 the relative pitch cues only (pitch contour and intervals. Children with normal hearing performed at high levels and comparably across the three conditions. The performance of child implant users was well above chance levels when both pitch and timing cues were available, marginally above chance with timing cues only, and at chance with pitch cues only. This is the first demonstration that children can identify familiar songs from monotonic versions—timing cues but no pitch cues—and from isochronous versions—pitch cues but no timing cues. The study also indicates that, in the context of a very simple task, young implant users readily identify songs from melodic versions that preserve pitch and timing cues.

  20. Comparison of individual pitch and smart rotor control strategies for load reduction

    Science.gov (United States)

    Plumley, C.; Leithead, W.; Jamieson, P.; Bossanyi, E.; Graham, M.

    2014-06-01

    Load reduction is increasingly seen as an essential part of controller and wind turbine design. On large multi-MW wind turbines that experience high levels of wind shear and turbulence across the rotor, individual pitch control and smart rotor control are being considered. While individual pitch control involves adjusting the pitch of each blade individually to reduce the cyclic loadings on the rotor, smart rotor control involves activating control devices distributed along the blades to alter the local aerodynamics of the blades. Here we investigate the effectiveness of using a DQ-axis control and a distributed (independent) control for both individual pitch and trailing edge flap smart rotor control. While load reductions are similar amongst the four strategies across a wide range of variables, including blade root bending moments, yaw bearing and shaft, the pitch actuator requirements vary. The smart rotor pitch actuator has reduced travel, rates, accelerations and power requirements than that of the individual pitch controlled wind turbines. This benefit alone however would be hard to justify the added design complexities of using a smart rotor, which can be seen as an alternative to upgrading the pitch actuator and bearing. In addition, it is found that the independent control strategy is apt at roles that the collective pitch usually targets, such as tower motion and speed control, and it is perhaps here, in supplementing other systems, that the future of the smart rotor lies.

  1. Pitch perception and production in congenital amusia: Evidence from Cantonese speakers

    Science.gov (United States)

    Liu, Fang; Chan, Alice H. D.; Ciocca, Valter; Roquet, Catherine; Peretz, Isabelle; Wong, Patrick C. M.

    2016-01-01

    This study investigated pitch perception and production in speech and music in individuals with congenital amusia (a disorder of musical pitch processing) who are native speakers of Cantonese, a tone language with a highly complex tonal system. Sixteen Cantonese-speaking congenital amusics and 16 controls performed a set of lexical tone perception, production, singing, and psychophysical pitch threshold tasks. Their tone production accuracy and singing proficiency were subsequently judged by independent listeners, and subjected to acoustic analyses. Relative to controls, amusics showed impaired discrimination of lexical tones in both speech and non-speech conditions. They also received lower ratings for singing proficiency, producing larger pitch interval deviations and making more pitch interval errors compared to controls. Demonstrating higher pitch direction identification thresholds than controls for both speech syllables and piano tones, amusics nevertheless produced native lexical tones with comparable pitch trajectories and intelligibility as controls. Significant correlations were found between pitch threshold and lexical tone perception, music perception and production, but not between lexical tone perception and production for amusics. These findings provide further evidence that congenital amusia is a domain-general language-independent pitch-processing deficit that is associated with severely impaired music perception and production, mildly impaired speech perception, and largely intact speech production. PMID:27475178

  2. Heroes and Villains: The Relationship between Pitch Tessitura and Sociability of Operatic Characters

    Directory of Open Access Journals (Sweden)

    Daniel Shanahan

    2015-01-01

    Full Text Available Research in speech prosody and ethology suggests that pitch height indexes positive and negative social affects, in the sense that higher pitched voices are used to convey friendliness, whereas lower pitched voices are used to convey aggression (Bolinger, 1964. Research concerning animal calls suggests that this association generalizes to many species. In a study of the calls for 56 species, Morton (1977, 1994 proposed a sound-size model in which large size (and low pitch is associated with aggression, whereas small size (and high pitch is associated with friendliness, fear, or appeasement. We examine whether this association can be observed in music. Specifically, the results of three studies are reported in which the pitch-height of various voices is related to estimates of the sociability of the corresponding operatic characters. Results indeed indicate an association between lower-pitched voices and less sociable characters, in contrast to higher-pitched voices being associated with more sociable characters. In addition, older male characters tend to exhibit lower-pitched voices, consistent with known physiological changes (Linville, 2004; Reubold, Harrington & Kleber, 2010.

  3. Return to Oz: voice pitch facilitates assessments of men's body size.

    Science.gov (United States)

    Pisanski, Katarzyna; Fraccaro, Paul J; Tigue, Cara C; O'Connor, Jillian J M; Feinberg, David R

    2014-08-01

    Listeners associate low voice pitch (fundamental frequency and/or harmonics) and formants (vocal-tract resonances) with large body size. Although formants reliably predict size within sexes, pitch does not reliably predict size in groups of same-sex adults. Voice pitch has therefore long been hypothesized to confound within-sex size assessment. Here we performed a knockout test of this hypothesis using whispered and 3-formant sine-wave speech devoid of pitch. Listeners estimated the relative size of men with above-chance accuracy from voiced, whispered, and sine-wave speech. Critically, although men's pitch and physical height were unrelated, the accuracy of listeners' size assessments increased in the presence rather than absence of pitch. Size assessments based on relatively low pitch yielded particularly high accuracy (70%-80%). Results of Experiment 2 revealed that amplitude, noise, and signal degradation of unvoiced speech could not explain this effect; listeners readily perceived formant shifts in manipulated whispered speech. Rather, in Experiment 3, we show that the denser harmonic spectrum provided by low pitch allowed for better resolution of formants, aiding formant-based size assessment. These findings demonstrate that pitch does not confuse body size assessment as has been previously suggested, but instead facilitates accurate size assessment by providing a carrier signal for vocal-tract resonances.

  4. Impact of pitching rate on yeast fermentation performance and beer flavour.

    Science.gov (United States)

    Verbelen, P J; Dekoninck, T M L; Saerens, S M G; Van Mulders, S E; Thevelein, J M; Delvaux, F R

    2009-02-01

    The volumetric productivity of the beer fermentation process can be increased by using a higher pitching rate (i.e. higher inoculum size). However, the impact of the pitching rate on crucial fermentation and beer quality parameters has never been assessed systematically. In this study, five pitching rates were applied to lab-scale fermentations to investigate its impact on the yeast physiology and beer quality. The fermentation rate increased significantly and the net yeast growth was lowered with increasing pitching rate, without affecting significantly the viability and the vitality of the yeast population. The build-up of unsaturated fatty acids in the initial phase of the fermentation was repressed when higher yeast concentrations were pitched. The expression levels of the genes HSP104 and HSP12 and the concentration of trehalose were higher with increased pitching rates, suggesting a moderate exposure to stress in case of higher cell concentrations. The influence of pitching rate on aroma compound production was rather limited, with the exception of total diacetyl levels, which strongly increased with the pitching rate. These results demonstrate that most aspects of the yeast physiology and flavour balance are not significantly or negatively affected when the pitching rate is changed. However, further research is needed to fully optimise the conditions for brewing beer with high cell density populations.

  5. Traceability strategy for gear-pitch-measuring instruments: development and calibration of a multiball artifact

    Science.gov (United States)

    Kondo, Yohan; Sasajima, Kazuyuki; Osawa, Sonko; Sato, Osamu; Komori, Masaharu

    2009-06-01

    There is a strong demand to ensure the traceability of gear-measuring instruments (GMIs). We propose a multiball artifact (MBA) for the evaluation of pitch-measuring accuracy. The aim of the MBA is to transfer the minimum uncertainty from a calibrated value at the National Metrology Institute of Japan (NMIJ) to a measured value of GMIs at a shop floor. The MBA is composed of equally spaced high-accuracy balls around an axis. The pitch-measuring accuracy of GMIs is evaluated by measuring the angular pitch deviation of the balls instead of the angular pitch deviation of a gear. We calibrated the angular pitch deviation using a coordinate measuring instrument (CMM) at the NMIJ and adapting a multiple-orientation technique. We proposed a calibration strategy of the angular pitch deviation. The calibration value of the pitch deviation for the MBA at the NMIJ was obtained with a measurement uncertainty (U95) of 0.2 µm. We evaluated the pitch-measuring accuracy of a GMI using the calibrated MBA. Each value of U95 for the cumulative and single pitch deviations for the left and right flanks was less than or equal to 0.5 µm. The small uncertainty was transferred from the NMIJ to the GMI.

  6. Production of Highly Charged Heavy Ions by means of a Hybrid Source in Dc mode and in Afterglow Mode

    Science.gov (United States)

    Gammino, S.; Ciavola, G.; Torrisi, L.; Andò, L.; Celona, L.; Presti, M.; Manciagli, S.; Picciotto, A.; Mezzasalma, A. M.; Krása, J.; Láska, L.; Pfeifer, M.; Wolowski, J.; Woryna, E.; Parys, P.; Shirkov, G. D.; Hitz, D.

    2005-03-01

    The ECLISSE experiment has been carried out by coupling a Laser Ion Source (based on a Nd:YAG laser (0.9 J / 9 ns, laser power densities metal samples without the use of ovens or sputtering technics were obtained in a variety of experimental conditions. The maximum charge states obtained from the ECRIS were 38+ for Ta and 41+ for Au. The peak current was obtained for 25+ and 29+ respectively and it was in the order of some tens of μA. In this work the analysis of some preliminary results obtained in afterglow mode will be also presented. We employed microwave pulse (length 4 msec) and laser pulse (length 9 nsec) with the same frequency (30 Hz) and variable relative phase. For appropriate phase values, a current enhancement of about one order of magnitude was observed.

  7. Upper tropospheric water vapour variability at high latitudes – Part 1: Influence of the annular modes

    Directory of Open Access Journals (Sweden)

    C. E. Sioris

    2016-03-01

    Full Text Available Seasonal and monthly zonal medians of water vapour in the upper troposphere and lower stratosphere (UTLS are calculated for both Atmospheric Chemistry Experiment (ACE instruments for the northern and southern high-latitude regions (60–90° N and 60–90° S. Chosen for the purpose of observing high-latitude processes, the ACE orbit provides sampling of both regions in 8 of 12 months of the year, with coverage in all seasons. The ACE water vapour sensors, namely MAESTRO (Measurements of Aerosol Extinction in the Stratosphere and Troposphere Retrieved by Occultation and the Fourier Transform Spectrometer (ACE-FTS are currently the only satellite instruments that can probe from the lower stratosphere down to the mid-troposphere to study the vertical profile of the response of UTLS water vapour to the annular modes. The Arctic oscillation (AO, also known as the northern annular mode (NAM, explains 64 % (r = −0.80 of the monthly variability in water vapour at northern high latitudes observed by ACE-MAESTRO between 5 and 7 km using only winter months (January to March, 2004–2013. Using a seasonal time step and all seasons, 45 % of the variability is explained by the AO at 6.5 ± 0.5 km, similar to the 46 % value obtained for southern high latitudes at 7.5 ± 0.5 km explained by the Antarctic oscillation or southern annular mode (SAM. A large negative AO event in March 2013 produced the largest relative water vapour anomaly at 5.5 km (+70 % over the ACE record. A similarly large event in the 2010 boreal winter, which was the largest negative AO event in the record (1950–2015, led to > 50 % increases in water vapour observed by MAESTRO and ACE-FTS at 7.5 km.

  8. Ultra-high negative dispersion compensating square lattice based single mode photonic crystal fiber with high nonlinearity

    Science.gov (United States)

    Islam, Md. Ibadul; Khatun, Maksuda; Ahmed, Kawsar

    2017-04-01

    This paper presents dispersion tailoring of photonic crystal fibers creating artificial defect along one of the regular square axes. A finite element method (FEM) has been enforced for numerical investigation of several guiding properties of the PCF covering a broad wavelength range about 1340-1640 nm over the telecommunication windows. According to simulation, the proposed PCF has obtained a strictly single-mode fiber, which has an ultra-high negative dispersion of about -584.60 to -2337.60 ps/(nm-km) and also possible to cover the highest nonlinearity order of 131.91 W-1 km-1 under the operating wavelength. Moreover, the proposed PCF structure experimentally focuses on higher nonlinear coefficient, which successfully compensates the chromatic dispersion of standard single mode in entire band of interest and greatly applicable to the optical transmission system. Additionally, the single mode behavior of S-PCF is explicated by employing V parameter. In our dispersion sensitive analysis, this fiber is significantly more robust due to successfully achieve ultra-high negative dispersion, which gains more promiscuous compared to the prior best results.

  9. Dual mode operation, highly selective nanohole array-based plasmonic colour filters

    Science.gov (United States)

    Fouladi Mahani, Fatemeh; Mokhtari, Arash; Mehran, Mahdiyeh

    2017-09-01

    Taking advantage of nanostructured metal films as plasmonic colour filters (PCFs) has been evolved remarkably as an alternative to the conventional technologies of chemical colour filtering. However, most of the proposed PCFs depict a poor colour purity focusing on generating either the additive or subtractive colours. In this paper, we present dual mode operation PCFs employing an opaque aluminium film patterned with sub-wavelength holes. Subtractive colours like cyan, magenta, and yellow are the results of reflection mode of these filters yielding optical efficiencies as high as 70%-80% and full width at half maximum of the stop-bands up to 40-50 nm. The colour selectivity of the transmission mode for the additive colours is also significant due to their enhanced performance through the utilization of a relatively thick aluminium film in contact with a modified dielectric environment. These filters provide a simple design with one-step lithography in addition to compatibility with the conventional CMOS processes. Moreover, they are polarization insensitive due to their symmetric geometry. A complete palette of pure subtractive and additive colours has been realized with potential applications, such as multispectral imaging, CMOS image sensors, displays, and colour printing.

  10. A differential low-voltage high gain current-mode integrated RF receiver front-end

    Science.gov (United States)

    Chunhua, Wang; Minglin, Ma; Jingru, Sun; Sichun, Du; Xiaorong, Guo; Haizhen, He

    2011-02-01

    A differential low-voltage high gain current-mode integrated RF front end for an 802.11b WLAN is proposed. It contains a differential transconductance low noise amplifier (Gm-LNA) and a differential current-mode down converted mixer. The single terminal of the Gm-LNA contains just one MOS transistor, two capacitors and two inductors. The gate-source shunt capacitors, Cx1 and Cx2, can not only reduce the effects of gate-source Cgs on resonance frequency and input-matching impedance, but they also enable the gate inductance Lg1,2 to be selected at a very small value. The current-mode mixer is composed of four switched current mirrors. Adjusting the ratio of the drain channel sizes of the switched current mirrors can increase the gain of the mixer and accordingly increase the gain of RF receiver front-end. The RF front-end operates under 1 V supply voltage. The receiver RFIC was fabricated using a chartered 0.18 μm CMOS process. The integrated RF receiver front-end has a measured power conversion gain of 17.48 dB and an input referred third-order intercept point (IIP3) of -7.02 dBm. The total noise figure is 4.5 dB and the power is only 14 mW by post-simulations.

  11. Sliding-Mode Control Applied for Robust Control of a Highly Unstable Aircraft

    Science.gov (United States)

    Vetter, Travis Kenneth

    2002-01-01

    An investigation into the application of an observer based sliding mode controller for robust control of a highly unstable aircraft and methods of compensating for actuator dynamics is performed. After a brief overview of some reconfigurable controllers, sliding mode control (SMC) is selected because of its invariance properties and lack of need for parameter identification. SMC is reviewed and issues with parasitic dynamics, which cause system instability, are addressed. Utilizing sliding manifold boundary layers, the nonlinear control is converted to a linear control and sliding manifold design is performed in the frequency domain. An additional feedback form of model reference hedging is employed which is similar to a prefilter and has large benefits to system performance. The effects of inclusion of actuator dynamics into the designed plant is heavily investigated. Multiple Simulink models of the full longitudinal dynamics and wing deflection modes of the forward swept aero elastic vehicle (FSAV) are constructed. Additionally a linear state space models to analyze effects from various system parameters. The FSAV has a pole at +7 rad/sec and is non-minimum phase. The use of 'model actuators' in the feedback path, and varying there design, is heavily investigated for the resulting effects on plant robustness and tolerance to actuator failure. The use of redundant actuators is also explored and improved robustness is shown. All models are simulated with severe failure and excellent tracking, and task dependent handling qualities, and low pilot induced oscillation tendency is shown.

  12. Dual pitch plasmonic devices for polarization enhanced colour based sensing

    Science.gov (United States)

    Langley, D.; Balaur, E.; Sadatnajafi, C.; Abbey, B.

    2016-12-01

    Plasmonic devices provide a unique sensitivity to changes in the permittivity of the immediate, near-surface environment. In this work we explore the use of dual pitch plasmonic devices combined with microfluidics for polarization enhanced colour sensing of a chemicals' refractive index. We demonstrate that the use of cross-shaped apertures can produce polarization tunable color based sensing in the optical regime and show that the spectral variations as a function of the incident polarization can be decomposed into contributions from the two orthogonal modes that characterize the dual pitch plasmonic device. Finally we demonstrate that the use of the full colour spectrum in the visible range in combination with polarization control enables sensing `by-eye' of refractive index changes below 1 × 10-3 RIU.

  13. Analysis of the Cause of High External Q Modes in the JLab High Gradient Prototype Cryomodule Renascence

    Energy Technology Data Exchange (ETDEWEB)

    Li, Z.; Akcelik, V.; Xiao, L.; Lee, L.; Ng, C.; Ko, K.; /SLAC; Wang, H.; Marhauser, F.; Sekutowicz, J.; Reece, C.; Rimmer, R.; /Jefferson Lab

    2008-06-27

    The Renascence cryomodule [1] installed in CEBAF in 2007 consists of 8 cavities as shown in Figure 1. The first three cavities (No.1-No.3) in the upstream end are of the Low Loss (LL) shape design, and the remaining 5 cavities (No.4-No.8) on the beam downstream end are the High Gradient (HG) shape design. The fundamental power couplers (FPCs) are the rectangular waveguides, and the little cylindrical structures are the HOM couplers. The locations of the FPC in the last four cavities are mirrored about the beam z axis. Cavities No.4 and No.5 form a back-to-back cavity pair. Among the HG cavities installed in the Renascence cryomodule, the only identifiable difference from their fabrication documentation is that cavity No.5 received an extra EBW pass on one equator weld, specifically cell 5. The non-uniform mechanical tuning required to compensate the fundamental mode tune and flatness for the extra shrinkage of this cell is believed to contribute the most significant differences from the other HG cavities. Beam based instability studies on this cryomodule in CEBAF have shown a significant beam breakup (BBU) threshold current reduction, well below design value. Frequency spectrum peaked by the off-sided beam power indicated the cause is due to abnormal high Q modes in the cavity No.5. Measured beam off-axis position at the cavity No.5 does not correspond to the shunt impedances calculated for an ideal cavity. Low power RF measurements have identified that the problematic modes are in the second dipole band (TM110 like). Three of the modes have external Qs two orders magnitude higher than the others, while the rest of modes in the first two dipole bands are normal in terms of the design values. The cause of this abnormality and the future impact on the BBU was not able to be resolved due to the limitations of information that can be obtained from the measurements. It is important to understand the cause of this abnormality so that effective QA/QC measures can be

  14. Characterization of pitches by solid state nuclear magnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Grint, A.; Proud, G.P.; Poplett, I.J.F.; Bartle, K.D.; Wallace, S.; Matthews, R.S. (The British Petroleum Company plc, Sunbury-on-Thames (UK). BP Research Centre)

    1989-11-01

    Solid petroleum, ethylene-cracker, and coal tar pitches were characterized by {sup 13}C cross-polarization-magic-angle-spinning nuclear magnetic resonance spectroscopy (CP/MAS n.m.r.) and by dipolar dephasing. The relative numbers of carbon atoms were determined by peak synthesis of the dipolar dephased (DD) spectrum and of the difference spectrum between the CP/MAS and DD spectra. Spectra and derived structural information obtained in this way were in good agreement with high-resolution n.m.r. spectra of pitch in solution. Solid state n.m.r. is shown to be an attractive alternative to the recording of spectra of pitches in reactive solvents. 11 refs., 3 figs., 3 tabs.

  15. Pitch Correlogram Clustering for Fast Speaker Identification

    Directory of Open Access Journals (Sweden)

    Nitin Jhanwar

    2004-12-01

    Full Text Available Gaussian mixture models (GMMs are commonly used in text-independent speaker identification systems. However, for large speaker databases, their high computational run-time limits their use in online or real-time speaker identification situations. Two-stage identification systems, in which the database is partitioned into clusters based on some proximity criteria and only a single-cluster GMM is run in every test, have been suggested in literature to speed up the identification process. However, most clustering algorithms used have shown limited success, apparently because the clustering and GMM feature spaces used are derived from similar speech characteristics. This paper presents a new clustering approach based on the concept of a pitch correlogram that captures frame-to-frame pitch variations of a speaker rather than short-time spectral characteristics like cepstral coefficient, spectral slopes, and so forth. The effectiveness of this two-stage identification process is demonstrated on the IVIE corpus of 110 speakers. The overall system achieves a run-time advantage of 500% as well as a 10% reduction of error in overall speaker identification.

  16. High-wavenumber Solar f-mode Strengthening Prior to Active Region Formation

    Science.gov (United States)

    Singh, Nishant K.; Raichur, Harsha; Brandenburg, Axel

    2016-12-01

    We report a systematic strengthening of the local solar surface or fundamental f-mode one to two days prior to the emergence of an active region (AR) in the same (corotating) location. Except for a possibly related increase in the kurtosis of the magnetic field, no indication can be seen in the magnetograms at that time. Our study is motivated by earlier numerical findings of Singh et al., which showed that, in the presence of a nonuniform magnetic field that is concentrated a few scale heights below the surface, the f-mode fans out in the diagnostic kω diagram at high wavenumbers. Here we explore this possibility using data from the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory and show for six isolated ARs, 11130, 11158, 11242, 11105, 11072, and 11768, that at large latitudinal wavenumbers (corresponding to horizontal scales of around 3000 {km}), the f-mode displays strengthening about two days prior to AR formation and thus provides a new precursor for AR formation. Furthermore, we study two ARs, 12051 and 11678, apart from a magnetically quiet patch lying next to AR 12529, to demonstrate the challenges in extracting such a precursor signal when a newly forming AR emerges in a patch that lies in close proximity to one or several already existing ARs, which are expected to pollute neighboring patches. We then discuss plausible procedures for extracting precursor signals from regions with crowded environments. The idea that the f-mode is perturbed days before any visible magnetic activity occurs at the surface can be important in constraining dynamo models aimed at understanding the global magnetic activity of the Sun.

  17. Gravitational Waves from F-modes Excited by the Inspiral of Highly Eccentric Neutron Star Binaries

    Energy Technology Data Exchange (ETDEWEB)

    Chirenti, Cecilia [Centro de Matemática, Computação e Cognição, UFABC, 09210-170 Santo André-SP (Brazil); Gold, Roman [Perimeter Institute for Theoretical Physics, 31 Caroline Street North, Waterloo, ON N2L 2Y5 (Canada); Miller, M. Coleman [Department of Astronomy and Joint Space-Science Institute, University of Maryland, College Park, MD 20742-2421 (United States)

    2017-03-01

    As gravitational wave instrumentation becomes more sensitive, it is interesting to speculate about subtle effects that could be analyzed using upcoming generations of detectors. One such effect that has great potential for revealing the properties of very dense matter is fluid oscillations of neutron stars. These have been found in numerical simulations of the hypermassive remnants of double neutron star mergers and of highly eccentric neutron star orbits. Here we focus on the latter and sketch out some ideas for the production, gravitational-wave detection, and analysis of neutron star oscillations. These events will be rare (perhaps up to several tens per year could be detected using third-generation detectors such as the Einstein Telescope or the Cosmic Explorer), but they would have unique diagnostic power for the analysis of cold, catalyzed, dense matter. Furthermore, these systems are unusual in that analysis of the tidally excited f-modes of the stars could yield simultaneous measurements of their masses, moments of inertia, and tidal Love numbers, using the frequency, damping time, and amplitude of the modes. They would thus present a nearly unique opportunity to test the I-Love-Q relation observationally. The analysis of such events will require significant further work in nuclear physics and general relativistic nonlinear mode coupling, and thus we discuss further directions that will need to be pursued. For example, we note that for nearly grazing encounters, numerical simulations show that the energy delivered to the f-modes may be up to two orders of magnitude greater than predicted in the linear theory.

  18. Electric Control Substituting Pitch Control for Large Wind Turbines

    Directory of Open Access Journals (Sweden)

    Jon Kjellin

    2013-01-01

    turbine has fixed pitch and is only controlled electrically accommodated by passive stall of the blades. By electrically controlling the generator rotational speed with the inverter, passive stall regulation is enabled. The first results on experimental verification of stall regulation in gusty wind speeds are presented. The experiments show that the control system can keep the turbine rotational speed constant even at very gusty winds. It is concluded that electrical control accommodated by passive stall is sufficient as control of the wind turbine even at high wind speeds and can substitute mechanical control such as blade pitch.

  19. Training English Listeners to Identify Pitch-Accent Patterns in Tokyo Japanese

    Science.gov (United States)

    Shport, Irina A.

    2016-01-01

    The high-variability training paradigm (multiple words, phonetic contexts, and talkers) has been successful for perceptual learning of tone contrasts. Here, it is extended to training native English listeners on Tokyo Japanese pitch-accent contrasts. Participants had no previous experience with lexically contrastive pitch patterns. They learned to…

  20. Do You See What I'm Singing? Visuospatial Movement Biases Pitch Perception

    Science.gov (United States)

    Connell, Louise; Cai, Zhenguang G.; Holler, Judith

    2013-01-01

    The nature of the connection between musical and spatial processing is controversial. While pitch may be described in spatial terms such as "high" or "low", it is unclear whether pitch and space are associated but separate dimensions or whether they share representational and processing resources. In the present study, we asked participants to…

  1. Risk of depression enhances auditory Pitch discrimination in the brain as indexed by the mismatch negativity.

    Science.gov (United States)

    Bonetti, L; Haumann, N T; Vuust, P; Kliuchko, M; Brattico, E

    2017-10-01

    Depression is a state of aversion to activity and low mood that affects behaviour, thoughts, feelings and sense of well-being. Moreover, the individual depression trait is associated with altered auditory cortex activation and appraisal of the affective content of sounds. Mismatch negativity responses (MMNs) to acoustic feature changes (pitch, timbre, location, intensity, slide and rhythm) inserted in a musical sequence played in major or minor mode were recorded using magnetoencephalography (MEG) in 88 subclinical participants with depression risk. We found correlations between MMNs to slide and pitch and the level of depression risk reported by participants, indicating that higher MMNs correspond to higher risk of depression. Furthermore we found significantly higher MMN amplitudes to mistuned pitches within a major context compared to MMNs to pitch changes in a minor context. The brains of individuals with depression risk are more responsive to mistuned and fast pitch stimulus changes, even at a pre-attentive level. Considering the altered appraisal of affective contents of sounds in depression and the relevance of spectral pitch features for those contents in music and speech, we propose that individuals with subclinical depression risk are more tuned to tracking sudden pitch changes. Copyright © 2017 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. All rights reserved.

  2. Difficulties with pitch discrimination influences pitch memory performance: evidence from congenital amusia.

    Science.gov (United States)

    Jiang, Cunmei; Lim, Vanessa K; Wang, Hang; Hamm, Jeff P

    2013-01-01

    Music processing is influenced by pitch perception and memory. Additionally these features interact, with pitch memory performance decreasing as the perceived distance between two pitches decreases. This study examined whether or not the difficulty of pitch discrimination influences pitch retention by testing individuals with congenital amusia. Pitch discrimination difficulty was equated by determining an individual's threshold with a two down one up staircase procedure and using this to create conditions where two pitches (the standard and the comparison tones) differed by 1x, 2x, and 3x the threshold setting. For comparison with the literature a condition that employed a constant pitch difference of four semitones was also included. The results showed that pitch memory performance improved as the discrimination between the standard and the comparison tones was made easier for both amusic and control groups, and more importantly, that amusics did not show any pitch retention deficits when the discrimination difficulty was equated. In contrast, consistent with previous literature, amusics performed worse than controls when the physical pitch distance was held constant at four semitones. This impaired performance has been interpreted as evidence for pitch memory impairment in the past. However, employing a constant pitch distance always makes the difference closer to the discrimination threshold for the amusic group than for the control group. Therefore, reduced performance in this condition may simply reflect differences in the perceptual difficulty of the discrimination. The findings indicate the importance of equating the discrimination difficulty when investigating memory.

  3. Difficulties with pitch discrimination influences pitch memory performance: evidence from congenital amusia.

    Directory of Open Access Journals (Sweden)

    Cunmei Jiang

    Full Text Available Music processing is influenced by pitch perception and memory. Additionally these features interact, with pitch memory performance decreasing as the perceived distance between two pitches decreases. This study examined whether or not the difficulty of pitch discrimination influences pitch retention by testing individuals with congenital amusia. Pitch discrimination difficulty was equated by determining an individual's threshold with a two down one up staircase procedure and using this to create conditions where two pitches (the standard and the comparison tones differed by 1x, 2x, and 3x the threshold setting. For comparison with the literature a condition that employed a constant pitch difference of four semitones was also included. The results showed that pitch memory performance improved as the discrimination between the standard and the comparison tones was made easier for both amusic and control groups, and more importantly, that amusics did not show any pitch retention deficits when the discrimination difficulty was equated. In contrast, consistent with previous literature, amusics performed worse than controls when the physical pitch distance was held constant at four semitones. This impaired performance has been interpreted as evidence for pitch memory impairment in the past. However, employing a constant pitch distance always makes the difference closer to the discrimination threshold for the amusic group than for the control group. Therefore, reduced performance in this condition may simply reflect differences in the perceptual difficulty of the discrimination. The findings indicate the importance of equating the discrimination difficulty when investigating memory.

  4. Nozzle designs with pitch precursor ablatives

    Science.gov (United States)

    Blevins, H. R.; Bedard, R. J.

    1976-01-01

    Recent developments in carbon phenolic ablatives for solid rocket motor nozzles have yielded a pitch precursor carbon fiber offering significant raw material availability and cost saving advantages as compared to conventional rayon precursor material. This paper discusses the results of an experimental program conducted to assess the thermal performance and characterize the thermal properties of pitch precursor carbon phenolic ablatives. The end result of this program is the complete thermal characterization of pitch fabric, pitch mat, hybrid pitch/rayon fabric and pitch mat molding compound. With these properties determined an analytic capability now exists for predicting the thermal performance of these materials in rocket nozzle liner applications. Further planned efforts to verify material performance and analytical prediction procedures through actual rocket motor firings are also discussed.

  5. Development and evaluation of wheel-controlled pitch-adjustable electrolarynx.

    Science.gov (United States)

    Wang, Li; Feng, Yijun; Yang, Ze; Niu, Haijun

    2017-08-01

    Tone is important in tonal languages, especially in Mandarin. However, there is presently no commercially available electrolarynx (EL) for laryngectomized Mandarin speakers. Moreover, few studies have focused on this area. Our purpose is to design an EL that produces the four Mandarin tones and to evaluate its performance. We designed a wheel-controlled pitch-adjustable EL and manufactured a prototype (Wheel-EL). Using monosyllables, disyllabic segments, and frequently used phrases, we evaluated speech produced by Wheel-EL and by monotone (M-TruTone) and variable-frequency modes (V-TruTone) of the commercially available TruTone EL. The pitch contours of the high-level (HL), middle-rising (MR), and falling-rising (FR) tones produced by Wheel-EL most closely matched the natural speech characteristics of a native speaker. However, redundant sounds were generated in the high-falling (HF) tone. The statistical accuracy of Wheel-EL's tone and word perception was significantly higher than that of other EL types. However, no significant differences existed in acceptability among the three EL speech types. Wheel-EL produces better HL, MR, and FR tones in Mandarin than either M-TruTone or V-TruTone. Nevertheless, redundant sounds affect HF phonation. Accurate tone judgment can improve the intelligibility of EL speech in Mandarin but has no obvious effect on acceptability.

  6. AIR ATMOSPHERIC-PRESSURE DISCHARGERS FOR OPERATION IN HIGH-FREQUENCY SWITCHING MODE.

    Directory of Open Access Journals (Sweden)

    L.S. Yevdoshenko

    2013-10-01

    Full Text Available Operation of two designs of compact multigap dischargers has been investigated in a high-frequency switching mode. It is experimentally revealed that the rational length of single discharge gaps in the designs is 0.3 mm, and the maximum switching frequency is 27000 discharges per second under long-term stable operation of the dischargers. It is shown that in pulsed corona discharge reactors, the pulse front sharpening results in increasing the operating electric field strength by 1.3 – 1.8 times.

  7. Common mode noise modeling and its suppression in ultra-high efficiency full bridge boost converter

    DEFF Research Database (Denmark)

    Makda, Ishtiyaq Ahmed; Nymand, Morten; Madawala, Udaya

    2013-01-01

    In this paper, common mode noise modeling of low-voltage high-current isolated full bridge boost dc-dc converters intended for fuel cell application is presented. Due to the tightly coupled primary and secondary windings of the transformer, such converter has inherently large capacitive coupling...... with the CISPR-A requirements. Finally, a 3kW dc-dc converter including filters has been built and tested to verify the theoretical model. Experimental results confirm the theoretical analysis of the converter....

  8. Synchronization of a coupled Hodgkin-Huxley neurons via high order sliding-mode feedback

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar-Lopez, R. [Division de Ciencias Basicas e Ingenieria, Universidad Autonoma Metropolitana, Av. San Pablo No. 180, Reynosa-Tamaulipas, 02200 Azcapotzalco, Mexico, D.F. (Mexico)], E-mail: raguilar@correo.azc.uam.mx; Martinez-Guerra, R. [Departamento de Control Automatico, CINVESTAV-IPN, Apartado Postal 14-740, Mexico, D.F. C.P. 07360 (Mexico)], E-mail: rguerra@ctrl.cinvestav.mx

    2008-07-15

    This work deals with the synchronizations of two both coupled Hodgkin-Huxley (H-H) neurons, where the master neuron posses inner noise and the slave neuron is considered in a resting state, (without inner noise) and an exciting state (with inner noise). The synchronization procedure is done via a feedback control, considering a class of high order sliding-mode controller which provides chattering reduction and finite time synchronization convergence, with a satisfactory performance. Theoretical analysis is done in order to show the closed-loop stability of the proposed controller and the calculated finite time for convergence. The main results are illustrated via numerical experiments.

  9. Top-Down Modulation on the Perception and Categorization of Identical Pitch Contours in Speech and Music

    Directory of Open Access Journals (Sweden)

    Joey L. Weidema

    2016-06-01

    Full Text Available Whether pitch in language and music is governed by domain-specific or domain-general cognitive mechanisms is contentiously debated. The aim of the present study was to investigate whether mechanisms governing pitch contour perception operate differently when pitch information is interpreted as either speech or music. By modulating listening mode, this study aspired to demonstrate that pitch contour perception relies on domain-specific cognitive mechanisms, which are regulated by top-down influences from language and music. Three groups of participants (Mandarin speakers, Dutch speaking non-musicians, and Dutch musicians were exposed to identical pitch contours, and tested on their ability to identify these contours in a language and musical context. Stimuli consisted of disyllabic words spoken in Mandarin, and melodic tonal analogues, embedded in a linguistic and melodic carrier phrase, respectively. Participants classified identical pitch contours as significantly different depending on listening mode. Top-down influences from language appeared to alter the perception of pitch contour in speakers of Mandarin. This was not the case for non-musician speakers of Dutch. Moreover, this effect was lacking in Dutch speaking musicians. The classification patterns of pitch contours in language and music seem to suggest that domain-specific categorization is modulated by top-down influences from language and music.

  10. Heavy vehicle pitch dynamics and suspension tuning

    OpenAIRE

    Cao, Dongpu; Rakheja, Subhash; Su, Chun-Yi

    2008-01-01

    The influence of suspension tuning of passenger cars on bounce and pitch ride performance has been explored in a number of studies, while only minimal efforts have been made for establishing similar rules for heavy vehicles. This study aims to explore pitch dynamics and suspension tunings of a two-axle heavy vehicle with unconnected suspension, which could also provide valuable information for heavy vehicles with coupled suspensions. Based on a generalised pitch-plane model of a two-axle heav...

  11. Mode decomposition methods for flows in high-contrast porous media. Global-local approach

    KAUST Repository

    Ghommem, Mehdi

    2013-11-01

    In this paper, we combine concepts of the generalized multiscale finite element method (GMsFEM) and mode decomposition methods to construct a robust global-local approach for model reduction of flows in high-contrast porous media. This is achieved by implementing Proper Orthogonal Decomposition (POD) and Dynamic Mode Decomposition (DMD) techniques on a coarse grid computed using GMsFEM. The resulting reduced-order approach enables a significant reduction in the flow problem size while accurately capturing the behavior of fully-resolved solutions. We consider a variety of high-contrast coefficients and present the corresponding numerical results to illustrate the effectiveness of the proposed technique. This paper is a continuation of our work presented in Ghommem et al. (2013) [1] where we examine the applicability of POD and DMD to derive simplified and reliable representations of flows in high-contrast porous media on fully resolved models. In the current paper, we discuss how these global model reduction approaches can be combined with local techniques to speed-up the simulations. The speed-up is due to inexpensive, while sufficiently accurate, computations of global snapshots. © 2013 Elsevier Inc.

  12. Tracking of pitch probabilities in congenital amusia.

    Science.gov (United States)

    Omigie, Diana; Pearce, Marcus T; Stewart, Lauren

    2012-06-01

    Auditory perception involves not only hearing a series of sounds but also making predictions about future ones. For typical listeners, these predictions are formed on the basis of long-term schematic knowledge, gained over a lifetime of exposure to the auditory environment. Individuals with a developmental disorder known as congenital amusia show marked difficulties with music perception and production. The current study investigated whether these difficulties can be explained, either by a failure to internalise the statistical regularities present in music, or by a failure to consciously access this information. Two versions of a melodic priming paradigm were used to probe participants' abilities to form melodic pitch expectations, in an implicit and an explicit manner. In the implicit version (Experiment 1), participants made speeded, forced-choice discriminations concerning the timbre of a cued target note. In the explicit version (Experiment 2), participants used a 1-7 rating scale to indicate the degree to which the pitch of the cued target note was expected or unexpected. Target notes were chosen to have high or low probability in the context of the melody, based on the predictions of a computational model of melodic expectation. Analysis of the data from the implicit task revealed a melodic priming effect in both amusic and control participants whereby both groups showed faster responses to high probability than low probability notes rendered in the same timbre as the context. However, analysis of the data from the explicit task revealed that amusic participants were significantly worse than controls at using explicit ratings to differentiate between high and low probability events in a melodic context. Taken together, findings from the current study make an important contribution in demonstrating that amusic individuals track melodic pitch probabilities at an implicit level despite an impairment, relative to controls, when required to make explicit

  13. Particle Distribution Modification by Low Amplitude Modes

    Energy Technology Data Exchange (ETDEWEB)

    White, R. B.; Gorelenkov, N.; Heidbrink, W. W.; Van Zeeland, M. A.

    2009-08-28

    Modification of a high energy particle distribution by a spectrum of low amplitude modes is investigated using a guiding center code. Only through resonance are modes effective in modifying the distribution. Diagnostics are used to illustrate the mode-particle interaction and to find which effects are relevant in producing significant resonance, including kinetic Poincare plots and plots showing those orbits with time averaged mode-particle energy transfer. Effects of pitch angle scattering and drag are studied, as well as plasma rotation and time dependence of the equilibrium and mode frequencies. A specific example of changes observed in a DIII-D deuterium beam distribution in the presence of low amplitude experimentally validated Toroidal Alfven (TAE) eigenmodes and Reversed Shear Alfven (RSAE) eigenmodes is examined in detail. Comparison with experimental data shows that multiple low amplitude modes can account for significant modification of high energy beam particle distributions. It is found that there is a stochastic threshold for beam profile modification, and that the experimental amplitudes are only slightly above this threshold.

  14. Adsorption detection for polylysine biomolecules based on high-Q silica capillary whispering gallery mode microresonator

    Science.gov (United States)

    Wu, Jixuan; Liu, Bo; Zhang, Hao; Song, Binbin

    2017-11-01

    A silica-capillary-based whispering gallery mode (WGM) microresonator has been proposed and experimentally demonstrated for the real-time monitoring of the polylysine adsorption process. The spectral characteristics of the WGM resonance dips with high quality factor and good wavelength selectivity have been investigated to evaluate the dynamic process for the binding of polylysine with a capillary surface. The WGM transmission spectrum shows a regular shift with increments of observation time, which could be exploited for the analysis of the polylysine adsorption process. The proposed WGM microresonator system possesses desirable qualities such as high sensitivity, fast response, label-free method, high detection resolution and compactness, which could find promising applications in histology and related bioengineering areas.

  15. Drilling Performance of Rock Drill by High-Pressure Water Jet under Different Configuration Modes

    Directory of Open Access Journals (Sweden)

    Songyong Liu

    2017-01-01

    Full Text Available In the rock drilling progress, the resistant force results in tools failure and the low drilling efficiency; thus, it is necessary to reduce the tools failure and enhance the drilling efficiency. In this paper, different configuration modes of drilling performance assisted with water jet are explored based on the mechanism and experiment analysis of rock drilling assisted with water jet. Moreover, the rotary sealing device with high pressure is designed to achieve the axial and rotation movement simultaneously as well as good sealing effect under high-pressure water jet. The results indicate that the NDB and NFB have better effects on drilling performance compared with that of NSB. Moreover, the high-pressure water jet is helpful not only to reduce the drill rod deflection, but also to reduce the probability of drill rod bending and improve the drill rod service life.

  16. Mode decomposition methods for flows in high-contrast porous media. A global approach

    KAUST Repository

    Ghommem, Mehdi

    2014-01-01

    We apply dynamic mode decomposition (DMD) and proper orthogonal decomposition (POD) methods to flows in highly-heterogeneous porous media to extract the dominant coherent structures and derive reduced-order models via Galerkin projection. Permeability fields with high contrast are considered to investigate the capability of these techniques to capture the main flow features and forecast the flow evolution within a certain accuracy. A DMD-based approach shows a better predictive capability due to its ability to accurately extract the information relevant to long-time dynamics, in particular, the slowly-decaying eigenmodes corresponding to largest eigenvalues. Our study enables a better understanding of the strengths and weaknesses of the applicability of these techniques for flows in high-contrast porous media. Furthermore, we discuss the robustness of DMD- and POD-based reduced-order models with respect to variations in initial conditions, permeability fields, and forcing terms. © 2013 Elsevier Inc.

  17. Detonation mode and frequency analysis under high loss conditions for stoichiometric propane-oxygen

    KAUST Repository

    Jackson, Scott

    2016-03-24

    The propagation characteristics of galloping detonations were quantified with a high-time-resolution velocity diagnostic. Combustion waves were initiated in 30-m lengths of 4.1-mm inner diameter transparent tubing filled with stoichiometric propane-oxygen mixtures. Chemiluminescence from the resulting waves was imaged to determine the luminous wave front position and velocity every 83.3 μ. As the mixture initial pressure was decreased from 20 to 7 kPa, the wave was observed to become increasingly unsteady and transition from steady detonation to a galloping detonation. While wave velocities averaged over the full tube length smoothly decreased with initial pressure down to half of the Chapman-Jouguet detonation velocity (DCJ) at the quenching limit, the actual propagation mechanism was seen to be a galloping wave with a cycle period of approximately 1.0 ms, corresponding to a cycle length of 1.3-2.0 m or 317-488 tube diameters depending on the average wave speed. The long test section length of 7300 tube diameters allowed observation of up to 20 galloping cycles, allowing for statistical analysis of the wave dynamics. In the galloping regime, a bimodal velocity distribution was observed with peaks centered near 0.4 DCJ and 0.95 DCJ. Decreasing initial pressure increasingly favored the low velocity mode. Galloping frequencies ranged from 0.8 to 1.0 kHz and were insensitive to initial mixture pressure. Wave deflagration-to-detonation transition and detonation failure trajectories were found to be repeatable in a given test and also across different initial mixture pressures. The temporal duration of wave dwell at the low and high velocity modes during galloping was also quantified. It was found that the mean wave dwell duration in the low velocity mode was a weak function of initial mixture pressure, while the mean dwell time in the high velocity mode depended exponentially on initial mixture pressure. Analysis of the velocity histories using dynamical systems ideas

  18. Discriminating the occurrence of pitch canker fungus in Pinus ...

    African Journals Online (AJOL)

    ... paper explores the utility of transformed high spatial resolution QuickBird imagery and artificial neural networks for the detection and mapping of pitch canker disease. Individual tree crowns were delineated using an automated segmentation and classification approach within an object-based image analysis environment.

  19. Highly resolved global distribution of tropospheric NO2 using GOME narrow swath mode data

    Directory of Open Access Journals (Sweden)

    S. Beirle

    2004-01-01

    Full Text Available The Global Ozone Monitoring Experiment (GOME allows the retrieval of tropospheric vertical column densities (VCDs of NO2 on a global scale. Regions with enhanced industrial activity can clearly be detected, but the standard spatial resolution of the GOME ground pixels (320x40km2 is insufficient to resolve regional trace gas distributions or individual cities. Every 10 days within the nominal GOME operation, measurements are executed in the so called narrow swath mode with a much better spatial resolution (80x40km2. We use this data (1997-2001 to construct a detailed picture of the mean global tropospheric NO2 distribution. Since - due to the narrow swath - the global coverage of the high resolution observations is rather poor, it has proved to be essential to deseasonalize the single narrow swath mode observations to retrieve adequate mean maps. This is done by using the GOME backscan information. The retrieved high resolution map illustrates the shortcomings of the standard size GOME pixels and reveals an unprecedented wealth of details in the global distribution of tropospheric NO2. Localised spots of enhanced NO2 VCD can be directly associated to cities, heavy industry centers and even large power plants. Thus our result helps to check emission inventories. The small spatial extent of NO2 'hot spots' allows us to estimate an upper limit of the mean lifetime of boundary layer NOx of 17h on a global scale. The long time series of GOME data allows a quantitative comparison of the narrow swath mode data to the nominal resolution. Thus we can analyse the dependency of NO2 VCDs on pixel size. This is important for comparing GOME data to results of new satellite instruments like SCIAMACHY (launched March 2002 on ENVISAT, OMI (launched July 2004 on AURA or GOME II (to be launched 2005 with an improved spatial resolution.

  20. High precision cross-correlated imaging in few-mode fibers

    Science.gov (United States)

    Muliar, Olena; Usuga Castaneda, Mario A.; Kristensen, Torben; Tanggaard Alkeskjold, Thomas; Rottwitt, Karsten; Lægsgaard, Jesper

    2017-01-01

    The trend of increasing data traffic in conventional communication systems demands utilizing new methods for data transmission, which in combination with traditional techniques, enable overcoming the predicted capacity limit. Mode division multiplexing (MDM), where higher-order modes (HOMs) in a few-mode fiber (FMF) are used as multiple spatial communication channels, comes in this context as a viable approach to enable the optimization of high-capacity links. From this perspective, it becomes highly necessary to possess a diagnostic tool for the precise modal characterization of FMFs. Among existing approaches for modal content analysis, several methods as S2, C2 in time and frequency domain are available. In this contribution we will present an improved time-domain cross-correlated (C2) imaging technique for the experimental evaluation of modal properties in HOM fibers over a broad range of wavelengths. Our modified setup makes it possible to adjust the time resolution of the system according to the needs of the required fiber measurement. We show that by tuning the spectral shape of the source (SuperK EXTREME filtered by SuperK Select), we enhance the time resolution of the system, which allows us to distinguishing differential time delays between HOMs in the picosecond timescale. Broad wavelength scanning in combination with spectral shaping, allows us to estimate the modal behavior of FMF without prior knowledge of the fiber parameters. We performed our demonstration at wavelengths from 850nm to 1100nm which can be easily extended to other wavelengths of interest just by replacing components with the appropriate coating. The method presented here aims to serve as flexible diagnostic tool that can be implemented in MDM systems for judicious evaluation of modal dispersion in FMFs.

  1. Generating high-peak-power structured lights in selectively pumped passively Q-switched lasers with astigmatic mode transformations

    Science.gov (United States)

    Chang, C. C.; Hsieh, Y. H.; Lee, C. Y.; Sung, C. L.; Tuan, P. H.; Tung, J. C.; Liang, H. C.; Chen, Y. F.

    2017-12-01

    Various high-order Hermite–Gaussian (HG) modes with high repetition rates and high peak powers are systematically generated by designing the cavity configuration to satisfy the criterion of the passive Q-switching. For the HG m,0 modes with the order m  =  1–9, the pulse repetition rate can exceed 100 kHz with peak power higher than 0.3 kW. For the HG m,m modes with the order m  =  1–10, the pulse repetition rate can be up to 37 kHz with peak power higher than 0.35 kW. Furthermore, the high-order HG beams is transformed by using an astigmatic mode converter to generate various structured lights with optical vortices. Experimental patterns of the transformed high-order HG beams in the propagation are theoretically analyzed and the phase structures are numerically manifested.

  2. Development of advanced blade pitching kinematics for cycloturbines and cyclorotors

    Science.gov (United States)

    Adams, Zachary Howard

    Cycloturbines and cyclorotors are established concepts for extracting freesteam fluid energy and producing thrust which promise to exceed the performance of traditional horizontal axis turbines and rotors while maintaining unique operational advantages. However, their potential is not yet realized in widespread applications. A central barrier to their proliferation is the lack of fundamental understanding of the aerodynamic interaction between the turbine and the freestream flow. In particular, blade pitch must be precisely actuated throughout the revolution to achieve the proper blade angle of attack and maximize performance. So far, there is no adequate method for determining or implementing the optimal blade pitching kinematics for cyclorotors or cycloturbines. This dissertation bridges the pitching deficiency by introducing a novel low order model to predict improved pitch kinematics, experimentally demonstrating improved performance, and evaluating flow physics with a high order Navier-Stokes computational code. The foundation for developing advanced blade pitch motions is a low order model named Fluxline Theory. Fluid calculations are performed in a coordinate system fixed to streamlines whose spatial locations are not pre-described in order to capture the flow expansion/contraction and bending through the turbine. A transformation then determines the spatial location of streamlines through the rotor disk and finally blade element method integrations determine the power and forces produced. Validation against three sets of extant cycloturbine experimental data demonstrates improvement over other existing streamtube models. Fluxline Theory was extended by removing dependence on a blade element model to better understand how turbine-fluid interaction impacts thrust and power production. This pure momentum variation establishes a cycloturbine performance limit similar to the Betz Limit for horizontal axis wind turbines, as well as the fluid deceleration required

  3. Observation of energy oscillation between strongly-coupled counter-propagating ultra-high Q whispering gallery modes.

    Science.gov (United States)

    Yoshiki, Wataru; Chen-Jinnai, Akitoshi; Tetsumoto, Tomohiro; Tanabe, Takasumi

    2015-11-30

    We report the first experimental observation of an energy oscillation between two coupled ultra-high Q whispering gallery modes in the time domain. Two counter-propagating whispering gallery modes in a silica toroid microcavity were employed for this purpose. The combination of a large coupling coefficient between the two modes and an ultra-high Q factor, which creates a large Γ value of > 10, results in a clear energy oscillation. Our measurement is based on a drop-port measurement technique, which enables us to observe the light energy in the two modes directly. The oscillation period measured in the time domain precisely matched that inferred from mode splitting in the frequency domain, and the measured results showed excellent agreement with results calculated with the developed numerical model.

  4. Factors influencing the separation of oligonucleotides using reversed-phase/ion-exchange mixed-mode high performance liquid chromatography columns.

    Science.gov (United States)

    Biba, Mirlinda; Jiang, Eileen; Mao, Bing; Zewge, Daniel; Foley, Joe P; Welch, Christopher J

    2013-08-23

    New mixed-mode columns consisting of reversed-phase and ion-exchange separation modes were evaluated for the analysis of short RNA oligonucleotides (∼20mers). Conventional analysis for these samples typically involves using two complementary methods: strong anion-exchange liquid chromatography (SAX-LC) for separation based on charge, and ion-pair reversed-phase liquid chromatography (IP-RPLC) for separation based on hydrophobicity. Recently introduced mixed-mode high performance liquid chromatography (HPLC) columns combine both reversed-phase and ion-exchange modes, potentially offering a simpler analysis by combining the benefits of both separation modes into a single method. Analysis of a variety of RNA oligonucleotide samples using three different mixed-mode stationary phases showed some distinct benefits for oligonucleotide separation and analysis. When using these mixed-mode columns with typical IP-RPLC mobile phase conditions, such as ammonium acetate or triethylammonium acetate as the primary ion-pair reagent, the separation was mainly based on the IP-RPLC mode. However, when changing the mobile phase conditions to those more typical for SAX-LC, such as salt gradients with NaCl or NaBr, very different separation patterns were observed due to mixed-mode interactions. In addition, the Scherzo SW-C18 and SM-C18 columns with sodium chloride or sodium bromide salt gradients also showed significant improvements in peak shape. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. The Advanced Bionics High Resolution Mode: stimulation rates up to 5000 pps.

    Science.gov (United States)

    Buechner, Andreas; Frohne-Büchner, Carolin; Gaertner, Lutz; Stoever, Timo; Battmer, Rolf D; Lenarz, Thomas

    2010-01-01

    The technology of stimulation rates between 1500 and 5000 pulses per second per channel (pps/ch) brings a benefit for all users. However, the fastest possible rate does not necessarily lead to best hearing performance in each individual subject. Individual optimization of stimulation rate is recommended. The aim of this study was to investigate the effect of high stimulation rates on speech perception ability. Thirteen subjects with at least 3 months of experience with conventional Clarion speech coding strategies were recruited into cross-over studies. The first study investigated stimulation rates of 1500, 2000 and 3000 pps/ch, the second study investigated rates of 2500 and 5000 pps/ch. Speech perception data were collected for testing in quiet and in competing noise. On average, speech perception performance increased significantly when changing from conventional speech coding strategies to High Resolution Mode. Subjects who preferred continous interleaved sampling (CIS) in standard mode appeared to obtain better results with rates of 2500 or 3000 pps/ch than with 5000 pps/ch. The stimulation rate that led to best performance provided the highest stimulation current efficiency in the majority of subjects.

  6. Characterization of enhanced D{alpha} high-confinement modes in Alcator {ital C}-Mod

    Energy Technology Data Exchange (ETDEWEB)

    Greenwald, M.; Boivin, R.; Bonoli, P.; Budny, R.; Fiore, C.; Goetz, J.; Granetz, R.; Hubbard, A.; Hutchinson, I.; Irby, J.; LaBombard, B.; Lin, Y.; Lipschultz, B.; Marmar, E.; Mazurenko, A.; Mossessian, D.; Sunn Pedersen, T.; Pitcher, C.S.; Porkolab, M.; Rice, J.; Rowan, W.; Snipes, J.; Schilling, G.; Takase, Y.; Terry, J.; Wolfe, S.; Weaver, J.; Welch, B.; Wukitch, S. [MIT-Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States)

    1999-05-01

    Regimes of high-confinement mode have been studied in the Alcator {ital C}-Mod tokamak [Hutchinson {ital et al.}, Phys. Plasmas {bold 1}, 1511 (1994)]. Plasmas with no edge localized modes (ELM-free) have been compared in detail to a new regime, enhanced D{alpha} (EDA). EDA discharges have only slightly lower energy confinement than comparable ELM-free ones, but show markedly reduced impurity confinement. Thus EDA discharges do not accumulate impurities and typically have a lower fraction of radiated power. The edge gradients in EDA seem to be relaxed by a continuous process rather than an intermittent one as is the case for standard ELMy discharges and thus do not present the first wall with large periodic heat loads. This process is probably related to fluctuations seen in the plasma edge. EDA plasmas are more likely at low plasma current (q{gt}3.7), for moderate plasma shaping, (triangularity {approximately}0.35{endash}0.55), and for high neutral pressures. As observed in soft x-ray emission, the pedestal width is found to scale with the same parameters that determine the EDA/ELM-free boundary. {copyright} {ital 1999 American Institute of Physics.}

  7. High Power Fast Wave Coupling and Heating in H-mode Plasmas on DIII-D

    Science.gov (United States)

    Pinsker, R. I.; Buttery, R. J.; Luce, T. C.; Porkolab, M.; Diem, S.; Kaufman, M.; Ryan, P. M.; Hosea, J. C.; Nagy, A.; Perkins, R.; Solomon, W. M.; Maggiora, R.; Milanesio, D.

    2012-10-01

    Up to 2.5 MW of fast wave (FW) heating power has been coupled to the core of ELMing H-mode discharges with βN<=2.5 in conjunction with 3-7 MW of neutral beam injection and 2.6 MW of electron cyclotron heating. Core FW heating efficiency has been found experimentally to approach 100% in the Advanced Inductive regime, consistent with the excellent absorption predicted by ray-tracing models in this high βe regime. Low antenna loading (high rf voltages) characteristic of such regimes makes increasing the FW power challenging. A study of techniques to enhance FW antenna loading has been carried out in DIII-D, with emphasis on maintenance of good confinement. The loading is in absolute agreement with modeling when edge density profiles measured with reflectometry are used in the model. Recent work extending the range of H-mode regimes to which FW heating has been applied and on increasing the FW power coupled to those regimes is described.

  8. Prospectively ECG-triggered high-pitch coronary angiography with third-generation dual-source CT at 70 kVp tube voltage: feasibility, image quality, radiation dose, and effect of iterative reconstruction.

    Science.gov (United States)

    Hell, Michaela M; Bittner, Daniel; Schuhbaeck, Annika; Muschiol, Gerd; Brand, Michael; Lell, Michael; Uder, Michael; Achenbach, Stephan; Marwan, Mohamed

    2014-01-01

    Low tube voltage reduces radiation exposure in coronary CT angiography (CTA). Using 70 kVp tube potential has so far not been possible because CT systems were unable to provide sufficiently high tube current with low voltage. We evaluated feasibility, image quality (IQ), and radiation dose of coronary CTA using a third-generation dual-source CT system capable of producing 450 mAs tube current at 70 kVp tube voltage. Coronary CTA was performed in 26 consecutive patients with suspected coronary artery disease, selected for body weight Image noise was lower in IR vs FBP (60 ± 10 HU vs 74 ± 8 HU; P < .001). In patients <100 kg and with a regular heart rate <60 beats/min, third-generation dual-source CT using high-pitch spiral acquisition and 70 kVp tube voltage is feasible and provides both robust IQ and very low radiation exposure. Copyright © 2014 Society of Cardiovascular Computed Tomography. Published by Elsevier Inc. All rights reserved.

  9. Parasites pitched against nature: Pitch Lake water protects guppies (Poecilia reticulata) from microbial and gyrodactylid infections.

    Science.gov (United States)

    Schelkle, Bettina; Mohammed, Ryan S; Coogan, Michael P; McMullan, Mark; Gillingham, Emma L; VAN Oosterhout, Cock; Cable, Joanne

    2012-11-01

    SUMMARY The enemy release hypothesis proposes that in parasite depleted habitats, populations will experience relaxed selection and become more susceptible (or less tolerant) to pathogenic infections. Here, we focus on a population of guppies (Poecilia reticulata) that are found in an extreme environment (the Pitch Lake, Trinidad) and examine whether this habitat represents a refuge from parasites. We investigated the efficacy of pitch in preventing microbial infections in Pitch Lake guppies, by exposing them to dechlorinated water, and reducing gyrodactylid infections on non-Pitch Lake guppies by transferring them to Pitch Lake water. We show that (i) natural prevalence of ectoparasites in the Pitch Lake is low compared to reference populations, (ii) Pitch Lake guppies transferred into aquarium water develop microbial infections, and (iii) experimentally infected guppies are cured of their gyrodactylid infections both by natural Pitch Lake water and by dechlorinated water containing solid pitch. These results indicate a role for Pitch Lake water in the defence of guppies from their parasites and suggest that Pitch Lake guppies might have undergone enemy release in this extreme environment. The Pitch Lake provides an ideal ecosystem for studies on immune gene evolution in the absence of parasites and long-term evolutionary implications of hydrocarbon pollution for vertebrates.

  10. Music therapy for chronic tinnitus: variability of tinnitus pitch in the course of therapy.

    Science.gov (United States)

    Hutter, Elisabeth; Grapp, Miriam; Argstatter, Heike; Bolay, Hans Volker

    2014-04-01

    In general, tinnitus pitch has been observed to be variable across time for most patients experiencing tinnitus. Some tinnitus therapies relate to the dominant tinnitus pitch in order to adjust therapeutic interventions. As studies focusing on tinnitus pitch rarely conduct consecutive pitch matching in therapeutic settings, little is known about the course and variability of tinnitus pitch during therapeutic interventions. The purpose of this study was to investigate the variability and development of tinnitus pitch in the course of therapeutic interventions. Tinnitus pitch was suspected to be highly variable. The researchers conducted a descriptive, retrospective analysis of data. A total of 175 adult patients experiencing chronic tinnitus served as participants. All patients had received a neuro-music therapy according to the "Heidelberg Model of Music Therapy for Chronic Tinnitus." During therapeutic interventions lasting for 5 consecutive days, the individual tinnitus frequency was assessed daily by means of a tinnitus pitch-matching procedure. The extent of variability in tinnitus pitch was calculated by mean ratios of frequencies between subsequent tinnitus measurements. Analysis of variance of repeated measures and post hoc paired samples t-tests were used for comparison of means in tinnitus frequencies, and the test-retest reliability of measurements was obtained by the Pearson product-moment correlation coefficient. Tinnitus pitch displayed a variability of approximately 3/5 to 4/5 octaves per day. Overall, the mean frequency declined in the course of the therapy. Detailed analysis revealed three groups of patients with diverging tinnitus progression. The test-retest reliability between assessments turned out to be robust (r = 0.74 or higher). Considerable variation in tinnitus pitch was found. Consequently, a frequent rechecking of tinnitus frequency is suggested during frequency-specific acoustic stimulation in order to train appropriate frequency bands

  11. HIGH-SPEED HOT EXTRUSION IN HIGH TEMPERATURE MECHANICAL TREATMENT MODE OF BIMETALLIC ROD PARTS OF THE STAMPS

    Directory of Open Access Journals (Sweden)

    I. V. Kachanov

    2016-01-01

    Full Text Available Processes of high-speed shaping change and especially high-speed hot extrusion create efficient conditions for treatment of low plastic and difficult-to-form materials which are widely used in tool making production. Due to the fact that high-speed stamping provides accurate billets with increased mechanical properties, it can be used as a technological process for manufacturing rod parts of die tooling operating under the increased loads and high wear. The purpose of the paper is to carry out experimental investigation of the possibility to obtain bimetallic rod stamping tooling by high-speed hot extrusion in high-temperature mode treatment in order to save die steels and improve the quality of the products obtained. Microstructures of the bimetallic compounds obtained with the help of high-speed hot extrusion method for compositions of structural and high-alloy steels have been investigated and their high quality has been proved during the investigations. Dependences of micro-hardness distribution have been established outbound two steel contact plane in the zone of connection that are characterized by a minimum micro-hardness value in the connection joint. Availability of more plastic zone in the contact plane contributes to reduction of residual stresses due to their relaxation in this zone and higher joint strength. 

  12. High-Input and Low-Output Impedance Voltage-Mode Universal DDCC and FDCCII Filter

    Science.gov (United States)

    Chen, Hua-Pin; Yang, Wan-Shing

    Despite the extensive literature on current conveyor-based universal (namely, low-pass, band-pass, high-pass, notch, and all-pass) biquads with three inputs and one output, no filter circuits have been reported to date which simultaneously achieve the following seven important features: (i) employment of only two current conveyors, (ii) employment of only grounded capacitors, (iii) employment of only grounded resistors, (iv) high-input and low-output impedance, (v) no need to employ inverting type input signals, (vi) no need to impose component choice conditions to realize specific filtering functions, and (vii) low active and passive sensitivity performances. This letter describes a new voltage-mode biquad circuit that satisfies all the above features simultaneously, and without trade-offs.

  13. A Low Voltage High Gain Transformer Noise-Canceling Current Mode Ultrawideband CMOS Low Noise Amplifier

    Science.gov (United States)

    Sun, Jingru; Cao, Xiaodong; Wang, Chunhua; Liu, Jinjiang; Zhao, Manfeng

    2012-03-01

    This paper presents a novel current mode differential UWB LNA. A common-gate stage with transformer realizes a low noise input matching and produces a current gain. The output of the LNA is differential current, which can avoid the current-to-voltage conversion. The LNA is simulated with TSMC 0.18 μm RF CMOS process. Simulation results show that the max noise figure is only 2.65 dB, transconductance gain is larger than 18.7 dB, input reflection coefficient is lower than -9.9 dB, and third order input intercept point is about 2.8 dBm over 3-5 GHz. With a voltage of 0.8 V, the power consumption is 11 mW. A comparison with conventional UWB LNA shows that this LNA has advantages of low voltage, low noise, high gain, and high linearity.

  14. A differential low-voltage high gain current-mode integrated RF receiver front-end

    Energy Technology Data Exchange (ETDEWEB)

    Wang Chunhua; Ma Minglin; Sun Jingru; Du Sichun; Guo Xiaorong; He Haizhen, E-mail: wch1227164@sina.com [School of Information Science and Technology, Hunan University, Changsha 410082 (China)

    2011-02-15

    A differential low-voltage high gain current-mode integrated RF front end for an 802.11b WLAN is proposed. It contains a differential transconductance low noise amplifier (G{sub m}-LNA) and a differential current-mode down converted mixer. The single terminal of the G{sub m}-LNA contains just one MOS transistor, two capacitors and two inductors. The gate-source shunt capacitors, C{sub x1} and C{sub x2}, can not only reduce the effects of gate-source C{sub gs} on resonance frequency and input-matching impedance, but they also enable the gate inductance L{sub g1,2} to be selected at a very small value. The current-mode mixer is composed of four switched current mirrors. Adjusting the ratio of the drain channel sizes of the switched current mirrors can increase the gain of the mixer and accordingly increase the gain of RF receiver front-end. The RF front-end operates under 1 V supply voltage. The receiver RFIC was fabricated using a chartered 0.18 {mu}m CMOS process. The integrated RF receiver front-end has a measured power conversion gain of 17.48 dB and an input referred third-order intercept point (IIP3) of -7.02 dBm. The total noise figure is 4.5 dB and the power is only 14 mW by post-simulations. (semiconductor integrated circuits)

  15. High-peak-power, high-repetition-rate LD end-pumped Nd:YVO4 burst mode laser

    Science.gov (United States)

    Pan, Hu; Yan, Renpeng; Fa, Xin; Yu, Xin; Ma, Yufei; Fan, Rongwei; Li, Xudong; Chen, Deying; Zhou, Zhongxiang

    2016-06-01

    A compact high-peak-power, high-repetition-rate burst mode laser is achieved by an acousto-optical Q-switched Nd:YVO4 1064 nm laser directly pumped at 878.6 nm. Pulse trains with 10-100 pulses are obtained using acousto-optical Q-switch at repetition rates of 10-100 kHz under a pulsed pumping with a 1 ms duration. At the maximum pump energy of 108.5 mJ, the pulse energy of 10 kHz burst mode laser reaches 44 mJ corresponding to a single pulse energy of 4.4 mJ and an optical-to-optical efficiency of 40.5 %.The maximum peak power of ~468.1 kW at 10 kHz is obtained with a pulse width of 9.4 ns. The beam quality factor is measured to be M 2 ~1.5 and the pulse jitter is estimated to be less than 1 % in both amplitude and time region.

  16. Objective correlates of pitch salience using pupillometry

    DEFF Research Database (Denmark)

    Bianchi, Federica; Santurette, Sébastien; Wendt, Dorothea

    2014-01-01

    Although objective correlates of pitch salience have been investigated in several neuroimaging studies, the results remain controversial. In the present study, a novel approach to objectively estimate pitch salience was used. Pupil dilation was measured as an indicator of the required effort in p...

  17. Individual Pitch Control Using LIDAR Measurements

    DEFF Research Database (Denmark)

    Mirzaei, Mahmood; Henriksen, Lars Christian; Poulsen, Niels Kjølstad

    2012-01-01

    In this work the problem of individual pitch control of a variable-speed variable-pitch wind turbine in the full load region is considered. Model predictive control (MPC) is used to solve the problem. However as the plant is nonlinear and time varying, a new approach is proposed to simplify...

  18. Learning Novel Musical Pitch via Distributional Learning

    Science.gov (United States)

    Ong, Jia Hoong; Burnham, Denis; Stevens, Catherine J.

    2017-01-01

    Because different musical scales use different sets of intervals and, hence, different musical pitches, how do music listeners learn those that are in their native musical system? One possibility is that musical pitches are acquired in the same way as phonemes, that is, via distributional learning, in which learners infer knowledge from the…

  19. Bifurcation and chaos in high-frequency peak current mode Buck converter

    Science.gov (United States)

    Chang-Yuan, Chang; Xin, Zhao; Fan, Yang; Cheng-En, Wu

    2016-07-01

    Bifurcation and chaos in high-frequency peak current mode Buck converter working in continuous conduction mode (CCM) are studied in this paper. First of all, the two-dimensional discrete mapping model is established. Next, reference current at the period-doubling point and the border of inductor current are derived. Then, the bifurcation diagrams are drawn with the aid of MATLAB. Meanwhile, circuit simulations are executed with PSIM, and time domain waveforms as well as phase portraits in i L-v C plane are plotted with MATLAB on the basis of simulation data. After that, we construct the Jacobian matrix and analyze the stability of the system based on the roots of characteristic equations. Finally, the validity of theoretical analysis has been verified by circuit testing. The simulation and experimental results show that, with the increase of reference current I ref, the corresponding switching frequency f is approaching to low-frequency stage continuously when the period-doubling bifurcation happens, leading to the converter tending to be unstable. With the increase of f, the corresponding I ref decreases when the period-doubling bifurcation occurs, indicating the stable working range of the system becomes smaller. Project supported by the National Natural Science Foundation of China (Grant No. 61376029), the Fundamental Research Funds for the Central Universities, China, and the College Graduate Research and Innovation Program of Jiangsu Province, China (Grant No. SJLX15_0092).

  20. Transverse Electromagnetic Mode Conversion for High-Harmonic Self-Probing Spectroscopy

    Directory of Open Access Journals (Sweden)

    Antoine Camper

    2015-02-01

    Full Text Available We report on high-order harmonic (HHG two-source interferometry (TSI in molecular gases. We used a 0-\\(\\pi\\ phase plate to create two bright spots at the focus of a lens by converting a Gaussian laser beam into a TEM please define \\(_{01}\\ Transverse Electromagnetic Mode. The two bright foci produce two synchronized HHG sources. One of them is used to probe on-going dynamics in the generating medium, while the other serves to heterodyne the signal. The interference of the emissions in the far–field gives access to the phase difference between the two sources. In self–probing HHG phase spectroscopy, one of the two sources is used as a reference while the other one probes some on goin dynamics in the generating medium. We first compute overlap integrals to investigate the mode conversion efficiency. We then establish a clear relation between the laser phase-front curvature and the far-field overlap of the two HHG beams. Both Fresnel diffraction calculations and an experimental lens position scan are used to reveal variations of the phase front inclination in each source. We show that this arrangement offers \\(\\frac{\\lambda_{XUV}}{100}\\ precision, enabling extremely sensitive phase measurements. Finally, we use this compact setup for TSI and measure phase variations across the molecular alignment revival of nitrogen and in vibrating sulfur hexafluoride. In both gases, the phase variations change sign around the ionization threshold of the investigated molecule.

  1. Digital Implementation of Method for Discontinuous Current Mode Compensation Of High-Performance Line-Commutated Converters

    CERN Document Server

    Maestri, S; Uicich, G; Gomez Costa, J; Petrocelli, R; CERN. Geneva. TE Department

    2010-01-01

    Many high-performance power converters at CERN are implemented with thyristors, mostly in CCM (Continuous Conduction Mode) due to their better dynamic response. In DCM (Discontinuous Conduction Mode), the converter reduces its small-signal gain, producing a degraded time response which can lead to instability. Several of these converters use digital regulation, allowing the implementation of complex non- linear control techniques. Therefore, a strategy to control the converters in DCM (Discontinuous Conduction Mode) can be implemented, bearing in mind that their standard operation (sampling time, measured signals, acquisition system) can not be drastically changed. This report presents the implementation of a new method to control line-commutated converters in discontinuous conduction mode (DCM). The method is based on the modfication of the thyristor's ring angle _ using a linear approximation, yielding nearly the same dynamic performance as in continuous conduction mode. The _ring angle is corrected by addi...

  2. Assessment of single-bolus contrast administration technique using hybrid dual-source ECG-gated thoracic and dual-source non-ECG-gated high-pitch abdominopelvic CT acquisitions for procedural planning before transcatheter aortic valve replacement.

    Science.gov (United States)

    Walker, Wendy L; Boll, Daniel T; Bueno, Juliana M; Kiefer, Todd L; Vavalle, John P; Gaca, Jeffrey G; Harrison, J Kevin; Hughes, G Chad; Wang, Andrew; Hurwitz, Lynne M

    2015-01-01

    This study aimed to assess vascular contrast opacification and homogeneity using single-bolus contrast administration with hybrid thoracic and abdominopelvic computed tomographic angiography in patients with severe aortic valve stenosis. Combination electrocardiogram-gated thoracic and dual-source, high-pitch abdominopelvic computed tomographic angiography examinations of 50 patients with severe aortic stenosis between December 2013 and March 2014 were reviewed. Contrast administration was individualized to patient-specific physiology. Image analysis of vascular opacification was obtained and interdependencies of vascular contrast and homogeneity of contrast distribution were assessed. The mean volume of contrast administered was 106 ± 11.7 mL. Mean attenuation was 371 ± 90.7 Hounsfield units (HU) in the thoracic aorta and 388 ± 95.9 HU in the abdominal aorta. Homogeneous opacification was obtained throughout with coefficient of variation of 11%. Procedural planning for transcatheter aortic valve replacement can be achieved using a single-injection bolus contrast protocol in combination with a 2-part multidetector computed tomographic image acquisition technique with optimal opacification of major arterial structures.

  3. Investigation on pitch system loads by means of an integral multi body simulation approach

    Science.gov (United States)

    Berroth, J.; Jacobs, G.; Kroll, T.; Schelenz, R.

    2016-09-01

    In modern horizontal axis wind turbines the rotor blades are adjusted by three individual pitch systems to control power output. The pitch system consists of either a hydraulic or an electrical actuator, the blade bearing, the rotor blade itself and the control. In case of an electrical drive a gearbox is used to transmit the high torques that are required for blade pitch angle adjustment. In this contribution a new integral multi body simulation approach is presented that enables detailed assessment of dynamic pitch system loads. The simulation results presented are compared and evaluated with measurement data of a 2 MW-class reference wind turbine. Major focus of this contribution is on the assessment of non linear tooth contact behaviour incorporating tooth backlash for the single gear stages and the impact on dynamic pitch system loads.

  4. Dissociation of procedural and semantic memory in absolute-pitch processing.

    Science.gov (United States)

    Hsieh, I-Hui; Saberi, Kourosh

    2008-06-01

    We describe two memory-retrieval systems in absolute-pitch (AP) processing and propose existence of a universal internal pitch template to which subpopulations of musicians selectively gain access through the two systems. In Experiment I, AP and control musicians adjusted the frequency of a pure tone to match the pitch of a visually displayed randomly selected musical note. In Experiment II the same subjects vocally produced within 2s the pitch associated with a randomly selected musical note label. AP musicians, but not controls, were highly accurate in frequency matching. Surprisingly, both AP and non-AP groups were extremely accurate in voicing the target pitch as determined from an FFT of the recorded voiced notes (i.e., sigma=0.97, 0.90 semitones, respectively). Spectrogram analysis showed that notes voiced by non-AP musicians are accurate from onset of voicing suggesting that pitch accuracy does not result from an auditory-motor feedback loop. Findings support existence of two memory-retrieval systems for musical pitch: a semantic associative form of memory used by AP musicians, and a more widespread form of procedural memory which allows precise access to internal pitch representations through the vocal-motor system.

  5. The strange physics of low frequency mirror mode turbulence in the high temperature plasma of the magnetosheath

    Directory of Open Access Journals (Sweden)

    R. A. Treumann

    2004-01-01

    Full Text Available Mirror mode turbulence is the lowest frequency perpendicular magnetic excitation in magnetized plasma proposed already about half a century ago by Rudakov and Sagdeev (1958 and Chandrasekhar et al. (1958 from fluid theory. Its experimental verification required a relatively long time. It was early recognized that mirror modes for being excited require a transverse pressure (or temperature anisotropy. In principle mirror modes are some version of slow mode waves. Fluid theory, however, does not give a correct physical picture of the mirror mode. The linear infinitesimally small amplitude physics is described correctly only by including the full kinetic theory and is modified by existing spatial gradients of the plasma parameters which attribute a small finite frequency to the mode. In addition, the mode is propagating only very slowly in plasma such that convective transport is the main cause of flow in it. As the lowest frequency mode it can be expected that mirror modes serve as one of the dominant energy inputs into plasma. This is however true only when the mode grows to large amplitude leaving the linear stage. At such low frequencies, on the other hand, quasilinear theory does not apply as a valid saturation mechanism. Probably the dominant processes are related to the generation of gradients in the plasma which serve as the cause of drift modes thus transferring energy to shorter wavelength propagating waves of higher nonzero frequency. This kind of theory has not yet been developed as it has not yet been understood why mirror modes in spite of their slow growth rate usually are of very large amplitudes indeed of the order of |B/B0|2~O(1. It is thus highly reasonable to assume that mirror modes are instrumental for the development of stationary turbulence in high temperature plasma. Moreover, since the magnetic field in mirror turbulence forms extended though slightly oblique magnetic bottles, low parallel energy particles can be trapped

  6. Variability of a "force signature" during windmill softball pitching and relationship between discrete force variables and pitch velocity.

    Science.gov (United States)

    Nimphius, Sophia; McGuigan, Michael R; Suchomel, Timothy J; Newton, Robert U

    2016-06-01

    This study assessed reliability of discrete ground reaction force (GRF) variables over multiple pitching trials, investigated the relationships between discrete GRF variables and pitch velocity (PV) and assessed the variability of the "force signature" or continuous force-time curve during the pitching motion of windmill softball pitchers. Intraclass correlation coefficient (ICC) for all discrete variables was high (0.86-0.99) while the coefficient of variance (CV) was low (1.4-5.2%). Two discrete variables were significantly correlated to PV; second vertical peak force (r(5)=0.81, p=0.03) and time between peak forces (r(5)=-0.79; p=0.03). High ICCs and low CVs support the reliability of discrete GRF and PV variables over multiple trials and significant correlations indicate there is a relationship between the ability to produce force and the timing of this force production with PV. The mean of all pitchers' curve-average standard deviation of their continuous force-time curves demonstrated low variability (CV=4.4%) indicating a repeatable and identifiable "force signature" pattern during this motion. As such, the continuous force-time curve in addition to discrete GRF variables should be examined in future research as a potential method to monitor or explain changes in pitching performance. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. Design of high-speed burst mode clock and data recovery IC for passive optical network

    Science.gov (United States)

    Yan, Minhui; Hong, Xiaobin; Huang, Wei-Ping; Hong, Jin

    2005-09-01

    Design of a high bit rate burst mode clock and data recovery (BMCDR) circuit for gigabit passive optical networks (GPON) is described. A top-down design flow is established and some of the key issues related to the behavioural level modeling are addressed in consideration for the complexity of the BMCDR integrated circuit (IC). Precise implementation of Simulink behavioural model accounting for the saturation of frequency control voltage is therefore developed for the BMCDR, and the parameters of the circuit blocks can be readily adjusted and optimized based on the behavioural model. The newly designed BMCDR utilizes the 0.18um standard CMOS technology and is shown to be capable of operating at bit rate of 2.5Gbps, as well as the recovery time of one bit period in our simulation. The developed behaviour model is verified by comparing with the detailed circuit simulation.

  8. The high-order cyclotron modes in Fermi liquid of Q2D layered conductors

    Directory of Open Access Journals (Sweden)

    O.V.Kirichenko

    2005-01-01

    Full Text Available The propagation of electromagnetic waves in layered conductors at the presence of an external magnetic field is investigated theoretically. At certain orientations of a magnetic field concerning the layers of the conductor the collisionless absorption is absent and weakly damping collective modes can propagate even under the strong spatial dispersion. In a short-wave limit the existence of electromagnetic waves with frequencies near the cyclotron resonances is possible at an arbitrary orientation of the wave vector with respect to an external magnetic field. We have obtained the spectrum of waves with the frequencies near the cyclotron resonances of high order with regard to the Fermi-liquid interaction of the electrons.

  9. Continuous high order sliding mode controller design for a flexible air-breathing hypersonic vehicle.

    Science.gov (United States)

    Wang, Jie; Zong, Qun; Su, Rui; Tian, Bailing

    2014-05-01

    This paper investigates the problem of tracking control with uncertainties for a flexible air-breathing hypersonic vehicle (FAHV). In order to overcome the analytical intractability of this model, an Input-Output linearization model is constructed for the purpose of feedback control design. Then, the continuous finite time convergence high order sliding mode controller is designed for the Input-Output linearization model without uncertainties. In addition, a nonlinear disturbance observer is applied to estimate the uncertainties in order to compensate the controller and disturbance suppression, where disturbance observer and controller synthesis design is obtained. Finally, the synthesis of controller and disturbance observer is used to achieve the tracking for the velocity and altitude of the FAHV and simulations are presented to illustrate the effectiveness of the control strategies. Copyright © 2014 ISA. Published by Elsevier Ltd. All rights reserved.

  10. Universal nonlinear scattering in ultra-high Q whispering gallery-mode resonators.

    Science.gov (United States)

    Lin, Guoping; Diallo, Souleymane; Dudley, John M; Chembo, Yanne K

    2016-06-27

    Universal nonlinear scattering processes such as Brillouin, Raman, and Kerr effects are fundamental light-matter interactions of particular theoretical and experimental importance. They originate from the interaction of a laser field with an optical medium at the lattice, molecular, and electronic scale, respectively. These nonlinear effects are generally observed and analyzed separately, because they do not often occur concomitantly. In this article, we report the simultaneous excitation of these three fundamental interactions in mm-size ultra-high Q whispering gallery mode resonators under continuous wave pumping. Universal nonlinear scattering is demonstrated in barium fluoride and strontium fluoride, separately. We further propose a unified theory based on a spatiotemporal formalism for the understanding of this phenomenology.

  11. Low-threshold stimulated Brillouin scattering in high-Q whispering gallery mode tellurite microspheres.

    Science.gov (United States)

    Guo, Changlei; Che, Kaijun; Zhang, Pan; Wu, Jinshu; Huang, Yantang; Xu, Huiying; Cai, Zhiping

    2015-12-14

    We demonstrate the first observation of stimulated Brillouin scattering (SBS) in a high-Q whispering gallery mode tellurite microsphere. Tellurite glass with composition of 70TeO₂-20ZnO-5Na₂O-5La₂O₃ (molar ratio) was prepared in-house using a melt-quenching technique. Moreover, tellurite microspheres with Q in excess of 13 millions at 1550 nm were fabricated by melting tellurite microwires using a CO₂ laser. By pumping the tellurite microspheres with a tunable single frequency laser, SBS is further realized with a threshold as low as 0.58 mW. At last, the beat notes between the pump and the Stokes signals were measured, which indicated the Brillouin frequency shift is at the 8.2 GHz band for our tellurite glass. Our results could propel significant applications utilizing SBS by employing tellurite microspheres.

  12. Semiconductor laser engineering, reliability and diagnostics a practical approach to high power and single mode devices

    CERN Document Server

    Epperlein, Peter W

    2013-01-01

    This reference book provides a fully integrated novel approach to the development of high-power, single-transverse mode, edge-emitting diode lasers by addressing the complementary topics of device engineering, reliability engineering and device diagnostics in the same book, and thus closes the gap in the current book literature. Diode laser fundamentals are discussed, followed by an elaborate discussion of problem-oriented design guidelines and techniques, and by a systematic treatment of the origins of laser degradation and a thorough exploration of the engineering means to enhance the optical strength of the laser. Stability criteria of critical laser characteristics and key laser robustness factors are discussed along with clear design considerations in the context of reliability engineering approaches and models, and typical programs for reliability tests and laser product qualifications. Novel, advanced diagnostic methods are reviewed to discuss, for the first time in detail in book literature, performa...

  13. High-order sliding mode observer for fractional commensurate linear systems with unknown input

    KAUST Repository

    Belkhatir, Zehor

    2017-05-20

    In this paper, a high-order sliding mode observer (HOSMO) is proposed for the joint estimation of the pseudo-state and the unknown input of fractional commensurate linear systems with single unknown input and a single output. The convergence of the proposed observer is proved using a Lyapunov-based approach. In addition, an enhanced variant of the proposed fractional-HOSMO is introduced to avoid the peaking phenomenon and thus to improve the estimation results in the transient phase. Simulation results are provided to illustrate the performance of the proposed fractional observer in both noise-free and noisy cases. The effect of the observer’s gains on the estimated pseudo-state and unknown input is also discussed.

  14. Optical Absorption in Commercial Single Mode Optical Fibers in a High Energy Physics Radiation Field

    CERN Document Server

    Wijnands, T; Kuhnhenn, J; Hoeffgen, S K; Weinand, U

    2008-01-01

    This paper reports on the radiation induced attenuation of light at 1310 nm and 1550 nm in 12 commercially available single mode (SM) optical fibers. The fiber samples are exposed to gamma rays from a 60Co source and to a high energy physics radiation field. The attenuation is studied as a function of total dose, dose rate, light power and temperature. Radiation hard fibers from one manufacturer show an extraordinary low attenuation for light at 1310 nm that does not exceed 5 dB/km even after a total dose of 1 MGy. 2500 km of this type of fiber have been produced by the manufacturer and quality assurance measurements of the production batches are presently ongoing.

  15. Unusually high-pitched neonate distress calls of the open-habitat Mongolian gazelle ( Procapra gutturosa) and their anatomical and hormonal predictors

    Science.gov (United States)

    Volodin, Ilya A.; Volodina, Elena V.; Frey, Roland; Kirilyuk, Vadim E.; Naidenko, Sergey V.

    2017-06-01

    In neonate ruminants, the acoustic structure of vocalizations may depend on sex, vocal anatomy, hormonal profiles and body mass and on environmental factors. In neonate wild-living Mongolian gazelles Procapra gutturosa, hand-captured during biomedical monitoring in the Daurian steppes at the Russian-Mongolian border, we spectrographically analysed distress calls and measured body mass of 22 individuals (6 males, 16 females). For 20 (5 male, 15 female) of these individuals, serum testosterone levels were also analysed. In addition, we measured relevant dimensions of the vocal apparatus (larynx, vocal folds, vocal tract) in one stillborn male Mongolian gazelle specimen. Neonate distress calls of either sex were high in maximum fundamental frequency (800-900 Hz), but the beginning and minimum fundamental frequencies were significantly lower in males than in females. Body mass was larger in males than in females. The levels of serum testosterone were marginally higher in males. No correlations were found between either body mass or serum testosterone values and any acoustic variable for males and females analysed together or separately. We discuss that the high-frequency calls of neonate Mongolian gazelles are more typical for closed-habitat neonate ruminants, whereas other open-habitat neonate ruminants (goitred gazelle Gazella subgutturosa, saiga antelope Saiga tatarica and reindeer Rangifer tarandus) produce low-frequency (fundamental frequency of distress calls of neonate Mongolian gazelles is their very short, atypical vocal folds (4 mm) compared to the 7-mm vocal folds of neonate goitred gazelles, producing distress calls as low as 120 Hz.

  16. Convolutional Pitch Target Approximation Model for Speech Synthesis

    OpenAIRE

    Na, Xingyu; Garner, Philip N.

    2013-01-01

    In this paper, we investigate pitch contour modelling in speech synthesis based on segmental units. A convolutional pitch target approximation model is proposed. This model allows jointly stochastic modelling of framewise pitch and pitch contour of longer units, of which the intuitive relations are revealed by a convolutional target approximation filter. The pitch contour is stylized by a linear representation called pitch target. In synthesis stage, the likelihood of the framewise model and ...

  17. Influence of musical and psychoacoustical training on pitch discrimination.

    Science.gov (United States)

    Micheyl, Christophe; Delhommeau, Karine; Perrot, Xavier; Oxenham, Andrew J

    2006-09-01

    This study compared the influence of musical and psychoacoustical training on auditory pitch discrimination abilities. In a first experiment, pitch discrimination thresholds for pure and complex tones were measured in 30 classical musicians and 30 non-musicians, none of whom had prior psychoacoustical training. The non-musicians' mean thresholds were more than six times larger than those of the classical musicians initially, and still about four times larger after 2h of training using an adaptive two-interval forced-choice procedure; this difference is two to three times larger than suggested by previous studies. The musicians' thresholds were close to those measured in earlier psychoacoustical studies using highly trained listeners, and showed little improvement with training; this suggests that classical musical training can lead to optimal or nearly optimal pitch discrimination performance. A second experiment was performed to determine how much additional training was required for the non-musicians to obtain thresholds as low as those of the classical musicians from experiment 1. Eight new non-musicians with no prior training practiced the frequency discrimination task for a total of 14 h. It took between 4 and 8h of training for their thresholds to become as small as those measured in the classical musicians from experiment 1. These findings supplement and qualify earlier data in the literature regarding the respective influence of musical and psychoacoustical training on pitch discrimination performance.

  18. Shoulder muscle firing patterns during the windmill softball pitch.

    Science.gov (United States)

    Maffet, M W; Jobe, F W; Pink, M M; Brault, J; Mathiyakom, W

    1997-01-01

    The purpose of this study was to describe the activity of eight shoulder muscles during the windmill fast-pitch softball throw. Ten collegiate female pitchers were analyzed with intramuscular electromyography, high-speed cinematography, and motion analysis. The supraspinatus muscle fired maximally during arm elevation from the 6 to 3 o'clock position phase, centralizing the humeral head within the glenoid. The posterior deltoid and teres minor muscles acted maximally from the 3 to 12 o'clock position phase to continue arm elevation and externally rotate the humerus. The pectoralis major muscle accelerated the arm from the 12 o'clock position to ball release phase. The serratus anterior muscle characteristically acted to position the scapula for optimal glenohumeral congruency, and the subscapularis muscle functioned as an internal rotator and to protect the anterior capsule. Although the windmill softball pitch is overtly different from the baseball pitch, several surprising similarities were revealed. The serratus anterior and pectoralis major muscles work in synchrony and seem to have similar functions in both pitches. Although the infraspinatus and teres minor muscles are both posterior cuff muscles, they are characteristically uncoupled during the 6 to 3 o'clock position phase, with the infraspinatus muscle acting more independently below 90 degrees. Subscapularis muscle activity seems important in dynamic anterior glenohumeral stabilization and as an internal rotator in both the baseball and softball throws.

  19. Highly Tm3+ doped germanate glass and its single mode fiber for 2.0 μm laser

    OpenAIRE

    Xin Wen; Guowu Tang; Qi Yang; Xiaodong Chen; Qi Qian; Qinyuan Zhang; Zhongmin Yang

    2016-01-01

    Highly Tm3+ doped optical fibers are urgently desirable for 2.0??m compact single-frequency fiber laser and high-repetition-rate mode-locked fiber laser. Here, we systematically investigated the optical parameters, energy transfer processes and thermal properties of Tm3+ doped barium gallo-germanate (BGG) glasses. Highly Tm3+ doped BGG glass single mode (SM) fibers were fabricated by the rod-in-tube technique. The Tm3+ doping concentration reaches 7.6???1020 ions/cm3, being the reported highe...

  20. A Generalized Subspace Least Mean Square Method for High-resolution Accurate Estimation of Power System Oscillation Modes

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Peng; Zhou, Ning; Abdollahi, Ali

    2013-09-10

    A Generalized Subspace-Least Mean Square (GSLMS) method is presented for accurate and robust estimation of oscillation modes from exponentially damped power system signals. The method is based on orthogonality of signal and noise eigenvectors of the signal autocorrelation matrix. Performance of the proposed method is evaluated using Monte Carlo simulation and compared with Prony method. Test results show that the GSLMS is highly resilient to noise and significantly dominates Prony method in tracking power system modes under noisy environments.

  1. Gender and vocal production mode discrimination using the high frequencies for speech and singing

    Directory of Open Access Journals (Sweden)

    Brian B Monson

    2014-10-01

    Full Text Available Humans routinely create acoustical energy at frequencies above 6 kHz during vocalization, but this frequency range is often not represented in communication devices and speech perception research. Recent advancements toward HD voice and extended bandwidth hearing aids have increased the interest in the high frequencies. The potential perceptual information provided by high-frequency energy (HFE is not well characterized. We found that humans can accomplish tasks of gender discrimination and vocal production mode discrimination (speech vs. singing when presented with acoustic stimuli containing only HFE at both amplified and normal levels. Performance in these tasks was robust in the presence of low-frequency masking noise. No substantial learning effect was observed. Listeners also were able to identify the sung and spoken text (excerpts from The Star-Spangled Banner with very few exposures. These results add to the increasing evidence that the high frequencies provide at least redundant information about the vocal signal, suggesting that its representation in communication devices (e.g., cell phones, hearing aids, and cochlear implants and speech/voice synthesizers could improve these devices and benefit normal-hearing and hearing-impaired listeners.

  2. Encoding pitch contours using current steering.

    Science.gov (United States)

    Luo, Xin; Landsberger, David M; Padilla, Monica; Srinivasan, Arthi G

    2010-09-01

    This study investigated cochlear implant (CI) users' ability to perceive pitch cues from time-varying virtual channels (VCs) to identify pitch contours. Seven CI users were tested on apical, medial, and basal electrode pairs with stimulus durations from 100 to 1000 ms. In one stimulus set, 9 pitch contours were created by steering current between the component electrodes and the VC halfway between the electrodes. Another stimulus set only contained 3 pitch contours (flat, falling, and rising). VC discrimination was also tested on the same electrodes. The total current level of dual-electrode stimuli was linearly interpolated between those of single-electrode stimuli to minimize loudness changes. The results showed that pitch contour identification (PCI) scores were similar across electrode locations, and significantly improved at longer durations. For durations longer than 300 ms, 2 subjects had nearly perfect 9-contour identification, and 5 subjects perfectly identified the 3 basic contours. Both PCI and VC discrimination varied greatly across subjects. Cumulative d(') values for VC discrimination were significantly correlated with 100-, 200-, and 500-ms PCI scores. These results verify the feasibility of encoding pitch contours using current steering, and suggest that identification of such pitch contours strongly relies on CI users' sensitivity to VCs.

  3. The role of pitch and temporal diversity in the perception and production of musical sequences.

    Science.gov (United States)

    Prince, Jon B; Pfordresher, Peter Q

    2012-10-01

    In two experiments we explored how the dimensions of pitch and time contribute to the perception and production of musical sequences. We tested how dimensional diversity (the number of unique categories in each dimension) affects how pitch and time combine. In Experiment 1, 18 musically trained participants rated the complexity of sequences varying only in their diversity in pitch or time; a separate group of 18 pianists reproduced these sequences after listening to them without practice. Overall, sequences with more diversity were perceived as more complex, but pitch diversity influenced ratings more strongly than temporal diversity. Further, although participants perceived sequences with high levels of pitch diversity as more complex, errors were more common in the sequences with higher diversity in time. Sequences in Experiment 2 exhibited diversity in both pitch and time; diversity levels were a subset of those tested in Experiment 1. Again diversity affected complexity ratings and errors, but there were no statistical interactions between dimensions. Nonetheless, pitch diversity was the primary factor in determining perceived complexity, and again temporal errors occurred more often than pitch errors. Additionally, diversity in one dimension influenced error rates in the other dimension in that both error types were more frequent relative to Experiment 1. These results suggest that although pitch and time do not interact directly, they are nevertheless not processed in an informationally encapsulated manner. The findings also align with a dimensional salience hypothesis, in which pitch is prioritised in the processing of typical Western musical sequences. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. Low is large: spatial location and pitch interact in voice-based body size estimation.

    Science.gov (United States)

    Pisanski, Katarzyna; Isenstein, Sari G E; Montano, Kelyn J; O'Connor, Jillian J M; Feinberg, David R

    2017-05-01

    The binding of incongruent cues poses a challenge for multimodal perception. Indeed, although taller objects emit sounds from higher elevations, low-pitched sounds are perceptually mapped both to large size and to low elevation. In the present study, we examined how these incongruent vertical spatial cues (up is more) and pitch cues (low is large) to size interact, and whether similar biases influence size perception along the horizontal axis. In Experiment 1, we measured listeners' voice-based judgments of human body size using pitch-manipulated voices projected from a high versus a low, and a right versus a left, spatial location. Listeners associated low spatial locations with largeness for lowered-pitch but not for raised-pitch voices, demonstrating that pitch overrode vertical-elevation cues. Listeners associated rightward spatial locations with largeness, regardless of voice pitch. In Experiment 2, listeners performed the task while sitting or standing, allowing us to examine self-referential cues to elevation in size estimation. Listeners associated vertically low and rightward spatial cues with largeness more for lowered- than for raised-pitch voices. These correspondences were robust to sex (of both the voice and the listener) and head elevation (standing or sitting); however, horizontal correspondences were amplified when participants stood. Moreover, when participants were standing, their judgments of how much larger men's voices sounded than women's increased when the voices were projected from the low speaker. Our results provide novel evidence for a multidimensional spatial mapping of pitch that is generalizable to human voices and that affects performance in an indirect, ecologically relevant spatial task (body size estimation). These findings suggest that crossmodal pitch correspondences evoke both low-level and higher-level cognitive processes.

  5. Perception of the pitch and naturalness of popular music by cochlear implant users.

    Science.gov (United States)

    Grasmeder, Mary L; Verschuur, Carl A

    2015-09-01

    To assess the perceived pitch and naturalness of popular music by cochlear implant (CI) users. Eleven experienced post-lingually deafened adult CI users rated the pitch, naturalness, and clarity of a popular song with 10 frequency allocation settings, including the default. The alternative settings all had logarithmic frequency spacing and frequency shifts of less than one octave compared with the default map. For maps which were perceived as having incorrect pitch, participants adjusted the pitch of the song in real time using a slider, in order to normalize it, and the amount of adjustment was recorded. The default map was rated as having close to correct pitch. Naturalness rating was negatively correlated with basal shift from a baseline logarithmic map, which was the same as the default map for basal electrodes (R(2) = 0.77). Ratings of the clarity of the lyrics were adversely affected by basal shift. The majority of participants were able to rate and adjust pitch appropriately. The frequency shift in the map was highly correlated with participants' adjustments of the pitch slider (R(2) = 0.94), but the adjustments were less than expected for the majority of participants. The pitch ratings for the default allocation suggest that participants have acclimatized to their processors' frequency allocations. Adjustment of the pitch of the song was possible for the majority and suggested that all but one participant was experiencing frequency compression. Expansion of the frequency allocation might help to alleviate this. Adjustment of the pitch of a popular song could be helpful for tuning CIs.

  6. X-mode HF Pump-induced Phenomena at High Heater Frequencies in the High Latitude Ionosphere F-region

    Science.gov (United States)

    Blagoveshchenskaya, N. F.; Borisova, T. D.; Kalishin, A. S.; Yeoman, T. K.; Häggström, I.

    2015-12-01

    Experimental results concentrating on X-mode HF-induced phenomena in the high latitude ionosphere F region are discussed. Experiments have been carried out at the HF Heating facility at Tromsø with an effective radiated power of 450 - 650 MW at high heater frequencies of 6.2 - 8.0 MHz. Multi-instriment diagnostics included the European Incoherent Scatter (EISCAT) UHF radar at 931 MHz at Tromsø, the Finland CUTLASS (Co-operative UK Twin Located Auroral Sounding System) radar, the stimulated electromagnetic emission (SEE) equipment at Tromsø, and the HF receiver near St. Petersburg for the observations of narrow band SEE features. The key parameter considered is the ratio between the heater frequency and critical frequency of the F2 layer (fH/foF2). We have analyzed the behaviors of small-scale artificial field-aligned irregularities (FAIs) and HF-enhanced plasma and ion lines (HFPLs and HFILs) depending on the pump proximity to the critical frequency. It was shown that the HFPLs and HFILs coexisted with FAIs throughout the whole heater pulse when fH/foF2 > 1 as well as fH/foF2 ≤ 1. It is indicative that parametric decay instability was not quenched by fully developed FAIs. The comparison between contrasting O/X mode HF-induced phenomena, when the heater frequency is below or near the critical frequency of F2 layer, is made. It was found that an X-mode HF pumping is able to excite different narrow band spectral components in the SEE spectra (within 1 kHz of pump frequency), such as ion acoustic, electrostatic ion cyclotron, and electrostatic ion cyclotron harmonic waves (otherwise known as neutralized ion Bernstein waves) observed at a long distance from the HF Heating facility. It was suggested that these spectral component can be attributed to the stimulated Brillion scatter (SBS) process. The results obtained show that an X-polarized electromagnetic wave scattered by SBS can propagate more than one thousand km without significant attenuation.

  7. Timing matters: the processing of pitch relations

    Science.gov (United States)

    Weise, Annekathrin; Grimm, Sabine; Trujillo-Barreto, Nelson J.; Schröger, Erich

    2014-01-01

    The human central auditory system can automatically extract abstract regularities from a variant auditory input. To this end, temporarily separated events need to be related. This study tested whether the timing between events, falling either within or outside the temporal window of integration (~350 ms), impacts the extraction of abstract feature relations. We utilized tone pairs for which tones within but not across pairs revealed a constant pitch relation (e.g., pitch of second tone of a pair higher than pitch of first tone, while absolute pitch values varied across pairs). We measured the mismatch negativity (MMN; the brain’s error signal to auditory regularity violations) to second tones that rarely violated the pitch relation (e.g., pitch of second tone lower). A Short condition in which tone duration (90 ms) and stimulus onset asynchrony between the tones of a pair were short (110 ms) was compared to two conditions, where this onset asynchrony was long (510 ms). In the Long Gap condition, the tone durations were identical to Short (90 ms), but the silent interval was prolonged by 400 ms. In Long Tone, the duration of the first tone was prolonged by 400 ms, while the silent interval was comparable to Short (20 ms). Results show a frontocentral MMN of comparable amplitude in all conditions. Thus, abstract pitch relations can be extracted even when the within-pair timing exceeds the integration period. Source analyses indicate MMN generators in the supratemporal cortex. Interestingly, they were located more anterior in Long Gap than in Short and Long Tone. Moreover, frontal generator activity was found for Long Gap and Long Tone. Thus, the way in which the system automatically registers irregular abstract pitch relations depends on the timing of the events to be linked. Pending that the current MMN data mirror established abstract rule representations coding the regular pitch relation, neural processes building these templates vary with timing. PMID:24966823

  8. Timing matters: The processing of pitch relations

    Directory of Open Access Journals (Sweden)

    Annekathrin eWeise

    2014-06-01

    Full Text Available The human central auditory system can automatically extract abstract regularities from a variant auditory input. To this end, temporarily separated events need to be related. This study tested whether the timing between events, falling either within or outside the temporal window of integration (~350 ms, impacts the extraction of abstract feature relations. We utilized tone pairs for which tones within but not across pairs revealed a constant pitch relation (e.g. pitch of 2nd tone of a pair higher than pitch of 1st tone, while absolute pitch values varied across pairs. We measured the Mismatch Negativity (MMN; the brain’s error signal to auditory regularity violations to 2nd tones that rarely violated the pitch relation (e.g. pitch of 2nd tone lower. A Short condition in which tone duration (90 ms and stimulus onset asynchrony between the tones of a pair were short (110 ms was compared to two conditions, where this onset asynchrony was long (510 ms. In the Long Gap condition the tone durations were identical to Short (90 ms, but the silent interval was prolonged by 400 ms. In Long Tone the duration of the first tone was prolonged by 400 ms, while the silent interval was comparable to Short (20 ms. Results show a frontocentral MMN of comparable amplitude in all conditions. Thus, abstract pitch relations can be extracted even when the within-pair timing exceeds the integration period. Source analyses indicate MMN generators in the supratemporal cortex. Interestingly, they were located more anterior in Long Gap than in Short and Long Tone. Moreover, frontal generator activity was found for Long Gap and Long Tone. Thus, the way in which the system automatically registers irregular abstract pitch relations depends on the timing of the events to be linked. Pending that the current MMN data mirror established abstract rule representations coding the regular pitch relation, neural processes building these templates vary with timing.

  9. Orthodontic bracket shear bond strengths produced by two high-power light-emitting diode modes and halogen light.

    Science.gov (United States)

    Türkkahraman, Hakan; Küçükeşmen, H Cenker

    2005-09-01

    The aim of this in vitro study was to compare the shear bond strength of orthodontic brackets cured with two different high-power light-emitting diode (LED) polymerization modes with traditional halogen polymerization. A total of forty-five extracted human premolar teeth were randomly divided into three groups. Each group consisted of 15 teeth mounted in an acrylic block. Following a standard enamel etching protocol, orthodontic brackets were cured on the first group of teeth with fast-mode LED, the second group with soft-start mode LED, and on the last group with a halogen light. After bonding, the shear bond strengths of the brackets were tested with a universal testing machine. The results showed that brackets cured with soft-start mode LED produced the highest shear bond strengths (23.86 +/- 6.20 MPa). No significant difference was found between fast-mode LED (17.14 +/- 5.75 MPa) and the halogen group (17.38 +/- 5.41 MPa) (P > .05). The LED is effective for bonding metal brackets to teeth, and the soft-start mode gives higher bond strengths than the fast mode.

  10. Effects of harmonic roving on pitch discrimination

    DEFF Research Database (Denmark)

    Santurette, Sébastien; de Kérangal, Mathilde le Gal; Joshi, Suyash Narendra

    2015-01-01

    external noise in the physical stimulus (Lu and Dosher, 2008). The present study used this approach to attempt to quantify the “internal noise” involved in pitch coding of harmonic complex tones by estimating the amount of harmonic roving required to impair pitch discrimination performance. It remains...... performance may help clarify pitch coding mechanisms. As training on frequency discrimination tasks has been found to result in a reduction of internal noise (Jones et al., 2013), it was also investigated whether the effect of harmonic roving varied with musical training...

  11. Single-mode temperature and polarisation-stable high-speed 850nm vertical cavity surface emitting lasers

    Science.gov (United States)

    Nazaruk, D. E.; Blokhin, S. A.; Maleev, N. A.; Bobrov, M. A.; Kuzmenkov, A. G.; Vasil'ev, A. P.; Gladyshev, A. G.; Pavlov, M. M.; Blokhin, A. A.; Kulagina, M. M.; Vashanova, K. A.; Zadiranov, Yu M.; Fefelov, A. G.; Ustinov, V. M.

    2014-12-01

    A new intracavity-contacted design to realize temperature and polarization-stable high-speed single-mode 850 nm vertical cavity surface emitting lasers (VCSELs) grown by molecular-beam epitaxy is proposed. Temperature dependences of static and dynamic characteristics of the 4.5 pm oxide aperture InGaAlAs VCSEL were investigated in detail. Due to optimal gain-cavity detuning and enhanced carrier localization in the active region the threshold current remains below 0.75 mA for the temperature range within 20-90°C, while the output power exceeds 1 mW up to 90°C. Single-mode operation with side-mode suppression ratio higher than 30 dB and orthogonal polarization suppression ratio more than 18 dB was obtained in the whole current and temperature operation range. Device demonstrates serial resistance less than 250 Ohm, which is rather low for any type of single-mode short- wavelength VCSELs. VCSEL demonstrates temperature robust high-speed operation with modulation bandwidth higher than 13 GHz in the entire temperature range of 20-90°C. Despite high resonance frequency the high-speed performance of developed VCSELs was limited by the cut-off frequency of the parasitic low pass filter created by device resistances and capacitances. The proposed design is promising for single-mode high-speed VCSEL applications in a wide spectral range.

  12. Superior time perception for lower musical pitch explains why bass-ranged instruments lay down musical rhythms.

    Science.gov (United States)

    Hove, Michael J; Marie, Céline; Bruce, Ian C; Trainor, Laurel J

    2014-07-15

    The auditory environment typically contains several sound sources that overlap in time, and the auditory system parses the complex sound wave into streams or voices that represent the various sound sources. Music is also often polyphonic. Interestingly, the main melody (spectral/pitch information) is most often carried by the highest-pitched voice, and the rhythm (temporal foundation) is most often laid down by the lowest-pitched voice. Previous work using electroencephalography (EEG) demonstrated that the auditory cortex encodes pitch more robustly in the higher of two simultaneous tones or melodies, and modeling work indicated that this high-voice superiority for pitch originates in the sensory periphery. Here, we investigated the neural basis of carrying rhythmic timing information in lower-pitched voices. We presented simultaneous high-pitched and low-pitched tones in an isochronous stream and occasionally presented either the higher or the lower tone 50 ms earlier than expected, while leaving the other tone at the expected time. EEG recordings revealed that mismatch negativity responses were larger for timing deviants of the lower tones, indicating better timing encoding for lower-pitched compared with higher-pitch tones at the level of auditory cortex. A behavioral motor task revealed that tapping synchronization was more influenced by the lower-pitched stream. Results from a biologically plausible model of the auditory periphery suggest that nonlinear cochlear dynamics contribute to the observed effect. The low-voice superiority effect for encoding timing explains the widespread musical practice of carrying rhythm in bass-ranged instruments and complements previously established high-voice superiority effects for pitch and melody.

  13. Quasi-linear diffusion coefficients for highly oblique whistler mode waves

    Science.gov (United States)

    Albert, J. M.

    2017-05-01

    Quasi-linear diffusion coefficients are considered for highly oblique whistler mode waves, which exhibit a singular "resonance cone" in cold plasma theory. The refractive index becomes both very large and rapidly varying as a function of wave parameters, making the diffusion coefficients difficult to calculate and to characterize. Since such waves have been repeatedly observed both outside and inside the plasmasphere, this problem has received renewed attention. Here the diffusion equations are analytically treated in the limit of large refractive index μ. It is shown that a common approximation to the refractive index allows the associated "normalization integral" to be evaluated in closed form and that this can be exploited in the numerical evaluation of the exact expression. The overall diffusion coefficient formulas for large μ are then reduced to a very simple form, and the remaining integral and sum over resonances are approximated analytically. These formulas are typically written for a modeled distribution of wave magnetic field intensity, but this may not be appropriate for highly oblique whistlers, which become quasi-electrostatic. Thus, the analysis is also presented in terms of wave electric field intensity. The final results depend strongly on the maximum μ (or μ∥) used to model the wave distribution, so realistic determination of these limiting values becomes paramount.

  14. Simulation of Double Tearing Modes with plasmoids in High Lundquist Number Regim

    Science.gov (United States)

    Ma, J.; Guo, W.

    2017-10-01

    A conservative perturbed MHD model and a flux vector splitting (FVS) based high order of accuracy finite difference method was applied to investigate the nonlinear evolution of double tearing modes(DTM) in 2D geometry with Lundquist number higher than 1.0e +4. With high spatial resolution approach, the results show the existence of multiple plasmoids generation. The effects of current sheets separation and guiding field upon secondary islands are investigated. It is also find that while the symmetry is well preserved during the simulation, a new quasi-stationary state with two pairs of islands can form after the explosive stage. For larger distance between rational surfaces two fast reconnections during one evolution can take place. Recently work, the numerical capability is extended to cylindrical geometry and validation during the linear and nonlinear DTM simulation in helical symmetry are performed. Work suppoted by National Natural Science Foundation of China under Grant No. 11475219 and the Science Foundation of the Institute of Plasma Physics, Chinese Academy of Sciences (DSJJ-15-JC02).

  15. Sliding Mode Pulsed Averaging IC Drivers for High Brightness Light Emitting Diodes

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Anatoly Shteynberg, PhD

    2006-08-17

    This project developed new Light Emitting Diode (LED) driver ICs associated with specific (uniquely operated) switching power supplies that optimize performance for High Brightness LEDs (HB-LEDs). The drivers utilize a digital control core with a newly developed nonlinear, hysteretic/sliding mode controller with mixed-signal processing. The drivers are flexible enough to allow both traditional microprocessor interface as well as other options such as “on the fly” adjustment of color and brightness. Some other unique features of the newly developed drivers include • AC Power Factor Correction; • High power efficiency; • Substantially fewer external components should be required, leading to substantial reduction of Bill of Materials (BOM). Thus, the LED drivers developed in this research : optimize LED performance by increasing power efficiency and power factor. Perhaps more remarkably, the LED drivers provide this improved performance at substantially reduced costs compared to the present LED power electronic driver circuits. Since one of the barriers to market penetration for HB-LEDs (in particular “white” light LEDs) is cost/lumen, this research makes important contributions in helping the advancement of SSL consumer acceptance and usage.

  16. Pitch control for ships with diesel mechanical and hybrid propulsion : Modelling, validation and performance quantification

    NARCIS (Netherlands)

    Geertsma, R.D.; Negenborn, R.R.; Visser, K.; Loonstijn, M.A.; Hopman, J.J.

    2017-01-01

    Ships, in particular service vessels, need to reduce fuel consumption, emissions and cavitation noise while maintaining manoeuvrability and preventing engine overloading. Diesel mechanical propulsion with controllable pitch propellers can provide high fuel efficiency with good manoeuvrability.

  17. Harmonic Training and the formation of pitch representation in a neural network model of the auditory brain

    Directory of Open Access Journals (Sweden)

    Nasir eAhmad

    2016-03-01

    Full Text Available Attempting to explain the perceptual qualities of pitch has proven to be, and remains, a difficult problem. The wide range of sounds which illicit pitch and a lack of agreement across neurophysiological studies on how pitch is encoded by the brain have made this attempt more difficult. In describing the potential neural mechanisms by which pitch may be processed, a number of neural networks have been proposed and implemented. However, no unsupervised neural networks with biologically accurate cochlear inputs have yet been demonstrated. This paper proposes a simplified system in which pitch representing neurons are easily produced under a highly biological setting. Purely unsupervised regimes of neural network learning are implemented and these prove to be sufficient in identifying the pitch of sounds with a variety of spectral profiles, including missing fundamental sounds.

  18. Actively mode-locked Tm(3+)-doped silica fiber laser with wavelength-tunable, high average output power.

    Science.gov (United States)

    Kneis, Christian; Donelan, Brenda; Berrou, Antoine; Manek-Hönninger, Inka; Robin, Thierry; Cadier, Benoît; Eichhorn, Marc; Kieleck, Christelle

    2015-04-01

    A diode-pumped, actively mode-locked high-power thulium (Tm3+)-doped double-clad silica fiber laser is demonstrated, providing an average output power in mode-locked (continuous wave) operation of 53 W (72 W) with a slope efficiency of 34% (38%). Mode-locking in the 6th-harmonic order was obtained by an acousto-optic modulator driven at 66 MHz without dispersion compensation. The shortest measured output pulse width was 200 ps. Owing to a diffraction grating as cavity end mirror, the central wavelength could be tuned from 1.95 to 2.13 μm. The measured beam quality in mode-locked and continuous wave operation has been close to the diffraction limit.

  19. TE01 mode converter for highly overmoded circular waveguide at 188 GHz

    DEFF Research Database (Denmark)

    Rybalko, Oleksandr; Zhurbenko, Vitaliy; Ardenkjær-Larsen, Jan Henrik

    2016-01-01

    A design of a G-band TE01 mode converter is presented in this work. It consists of a TE01 mode launcher followed by a tapered waveguide section. Full-wave simulated reflection coefficient of stainless steel converter is better than −15 dB and transmission coefficient is better than −1.5 d...

  20. Voice Pitch Influences Perceptions of Sexual Infidelity

    National Research Council Canada - National Science Library

    O'Connor, Jillian J.M; Re, Daniel E; Feinberg, David R

    2011-01-01

    .... Among men, testosterone is inversely related to voice pitch, relationship and offspring investment, and is positively related to the pursuit of short-term relationships, including extra-pair sex...

  1. Surface Electromyography of the Forearm Musculature During the Windmill Softball Pitch.

    Science.gov (United States)

    Remaley, D Trey; Fincham, Bryce; McCullough, Bryan; Davis, Kirk; Nofsinger, Charles; Armstrong, Charles; Stausmire, Julie M

    2015-01-01

    Previous studies investigating the windmill softball pitch have focused primarily on shoulder musculature and function, collecting limited data on elbow and forearm musculature. Little information is available in the literature regarding the forearm. This study documents forearm muscle electromyographic (EMG) activity that has not been previously published. Elbow and upper extremity overuse injuries are on the rise in fast-pitch softball pitchers. This study attempts to describe forearm muscle activity in softball pitchers during the windmill softball pitch. Overuse injuries can be prevented if a better understanding of mechanics is defined. Descriptive laboratory study. Surface EMG and high-speed videography was used to study forearm muscle activation patterns during the windmill softball pitch on 10 female collegiate-level pitchers. Maximum voluntary isometric contraction of each muscle was used as a normalizing value. Each subject was tested during a single laboratory session per pitcher. Data included peak muscle activation, average muscle activation, and time to peak activation for 6 pitch types: fastball, changeup, riseball, curveball, screwball, and dropball. During the first 4 phases, muscle activity (seen as signal strength on the EMG recordings) was limited and static in nature. The greatest activation occurred in phases 5 and 6, with increased signal strength, evidence of stretch-shortening cycle, and different muscle characteristics with each pitch style. These 2 phases of the windmill pitch are where the arm is placed in the 6 o'clock position and then at release of the ball. The flexor carpi ulnaris signal strength was significantly greater than the other forearm flexors. Timing of phases 1 through 5 was successively shorter for each pitch. There was a secondary pattern of activation in the flexor carpi ulnaris in phase 4 for all pitches except the fastball and riseball. During the 6 pitches, the greatest muscular activity was in phases 5 and 6

  2. Pitch synchronous transform warping in voice conversion

    OpenAIRE

    Vích, R. (Robert); Vondra, M. (Martin)

    2012-01-01

    In this paper a new voice conversion algorithm is presented, which transforms the utterance of a source speaker into the utterance of a target speaker. The voice conversion approach is based on pitch synchronous speech analysis, Discrete Cosine Transform (DCT), nonlinear spectral warping with spectrum interpolation and pitch synchronous speech synthesis with overlapping using the speech production model. The DCT speech model contains also information about the phase properties of the modeled ...

  3. Influence of a helical pitch on orthoconic antiferroelectric liquid crystals performance

    Science.gov (United States)

    Bennis, N.; Dąrowski, R.; Rejmer, W.; Spadło, A.; Quintana, X.; Otón, J. M.

    2011-03-01

    Orthoconic antiferroelectric liquid crystals, whose half cone angle is 45°, are of interest in display technology because they are capable of providing greyscale in passively addressing waveform while exhibiting very good contrast. However, orthoconic antiferroelectrics having short pitch are difficult to be aligned, this makes surface stabilized alignment unfeasible. In this case, dynamic behaviour is usually poor, avoiding electronic addressing with standard electronics. In this work, we report the helical pitch measurements of OAFLC mixtures and we compare electrooptical performance of high and low pitch OAFLCs.

  4. A novel PI pitch controller and energy capacitor system for reducing wind power fluctuations and keeping micro-grid stable subsequent islanding occurrence

    Energy Technology Data Exchange (ETDEWEB)

    Kamel, R.M.; Chaouachi, A.; Nagasaka, K.

    2010-07-01

    This paper presented a newly developed model for simulating the transient dynamic performance of a micro-grid (MG) during and following an islanding process. Changes in wind speed result in high variability in the power output of wind turbines which lead to fluctuations in frequency and voltage of the MG, particularly during islanding mode. The newly proposed PI pitch controller and energy storage ultra capacitor is meant to smooth the output power from a wind turbine in order to reduce frequency and voltage fluctuations. Improvement of the MG performance confirmed the effects of the proposed controllers.

  5. Determination of football pitch locations from video footage and official pitch markings.

    Science.gov (United States)

    Alcock, Alison; Hunter, Adam; Brown, Nicholas

    2009-06-01

    The ability to determine a specific location on a football (soccer) pitch from television footage would provide a cost-effective method of obtaining competition-specific information on many professional and international teams. This study presents the accuracy and reliability of a new method of calculating ball location from simulated television coverage and known pitch markings. The coordinates of 99 markers of known location on a football pitch were digitized from video. An intersection point was determined from the equations of two lines that form pitch markings and the relationship from this point to other known pitch coordinates was calculated using a curve-fitting based method. Average error between known and reconstructed measures was 0.21 m for pitch width and 0.11 m for pitch length from a view simulating television coverage. Inter- and intra-rater reliability analyses showed researchers could consistently reconstruct pitch locations to within less than half a metre. The accuracy and reliability of this method will be sufficient for most practical uses in an applied sport environment, although the level of accuracy required will depend on the specific application. This method could be applied to other sports to determine specific locations on a pitch or court or to improve current competition analysis systems.

  6. Perceptual Pitch Deficits Coexist with Pitch Production Difficulties in Music but Not Mandarin Speech

    Directory of Open Access Journals (Sweden)

    Wu-xia eYang

    2014-01-01

    Full Text Available Congenital amusia is a musical disorder that mainly affects pitch perception. Among Mandarin speakers, some amusics also have difficulties in processing lexical tones (tone agnosics. To examine to what extent these perceptual deficits may be related to pitch production impairments in music and Mandarin speech, 8 amusics, 8 tone agnosics, and 12 age- and IQ-matched normal native Mandarin speakers were asked to imitate music note sequences and Mandarin words of comparable lengths. The results indicated that both the amusics and tone agnosics underperformed the controls on musical pitch production. However, tone agnosics performed no worse than the amusics, suggesting that lexical tone perception deficits may not aggravate musical pitch production difficulties. Moreover, these three groups were all able to imitate lexical tones with perfect intelligibility. Taken together, the current study shows that perceptual musical pitch and lexical tone deficits might coexist with musical pitch production difficulties. But at the same time these perceptual pitch deficits might not affect lexical tone production or the intelligibility of the speech words that were produced. The perception-production relationship for pitch among individuals with perceptual pitch deficits may be, therefore, domain-dependent.

  7. Perceptual pitch deficits coexist with pitch production difficulties in music but not Mandarin speech.

    Science.gov (United States)

    Yang, Wu-Xia; Feng, Jie; Huang, Wan-Ting; Zhang, Cheng-Xiang; Nan, Yun

    2013-01-01

    Congenital amusia is a musical disorder that mainly affects pitch perception. Among Mandarin speakers, some amusics also have difficulties in processing lexical tones (tone agnosics). To examine to what extent these perceptual deficits may be related to pitch production impairments in music and Mandarin speech, eight amusics, eight tone agnosics, and 12 age- and IQ-matched normal native Mandarin speakers were asked to imitate music note sequences and Mandarin words of comparable lengths. The results indicated that both the amusics and tone agnosics underperformed the controls on musical pitch production. However, tone agnosics performed no worse than the amusics, suggesting that lexical tone perception deficits may not aggravate musical pitch production difficulties. Moreover, these three groups were all able to imitate lexical tones with perfect intelligibility. Taken together, the current study shows that perceptual musical pitch and lexical tone deficits might coexist with musical pitch production difficulties. But at the same time these perceptual pitch deficits might not affect lexical tone production or the intelligibility of the speech words that were produced. The perception-production relationship for pitch among individuals with perceptual pitch deficits may be, therefore, domain-dependent.

  8. Absence of modulatory action on haptic height perception with musical pitch

    Directory of Open Access Journals (Sweden)

    Michele eGeronazzo

    2015-09-01

    Full Text Available Although acoustic frequency is not a spatial property of physical objects, in common language, pitch, i.e., the psychological correlated of frequency, is often labeled spatially (i.e., high in pitch or low in pitch. Pitch-height is known to modulate (and interact with the response of participants when they are asked to judge spatial properties of non-auditory stimuli (e.g., visual in a variety of behavioral tasks. In the current study we investigated whether the modulatory action of pitch-height extended to the haptic estimation of height of a virtual step.We implemented a HW/SW setup which is able to render virtual 3D objects (stair-steps haptically through a PHANTOM device, and to provide real-time continuous auditory feedback depending on the user interaction with the object. The haptic exploration was associated with a sinusoidal tone whose pitch varied as a function of the interaction point’s height within (i a narrower and (ii a wider pitch range, or (iii a random pitch variation acting as a control audio condition. Explorations were also performed with no sound (haptic only. Participants were instructed to explore the virtual step freely, and to communicate height estimation by opening their thumb and index finger to mimic the step riser height, or verbally by reporting the height in centimeters of the step riser. We analyzed the role of musical expertise by dividing participants into non musicians and musicians. Results showed no effects of musical pitch on high-realistic haptic feedback. Overall there is no difference between the two groups in the proposed multimodal conditions. Additionally, we observed a different haptic response distribution between musicians and non musicians when estimations of the auditory conditions are matched with estimations in the no sound condition.

  9. Active and passive stabilization of body pitch in insect flight.

    Science.gov (United States)

    Ristroph, Leif; Ristroph, Gunnar; Morozova, Svetlana; Bergou, Attila J; Chang, Song; Guckenheimer, John; Wang, Z Jane; Cohen, Itai

    2013-08-06

    Flying insects have evolved sophisticated sensory-motor systems, and here we argue that such systems are used to keep upright against intrinsic flight instabilities. We describe a theory that predicts the instability growth rate in body pitch from flapping-wing aerodynamics and reveals two ways of achieving balanced flight: active control with sufficiently rapid reactions and passive stabilization with high body drag. By glueing magnets to fruit flies and perturbing their flight using magnetic impulses, we show that these insects employ active control that is indeed fast relative to the instability. Moreover, we find that fruit flies with their control sensors disabled can keep upright if high-drag fibres are also attached to their bodies, an observation consistent with our prediction for the passive stability condition. Finally, we extend this framework to unify the control strategies used by hovering animals and also furnish criteria for achieving pitch stability in flapping-wing robots.

  10. High-resolution monochromator using a high-efficiency single-mode x-ray resonator at Laue incidence.

    Science.gov (United States)

    Wu, Yu-Hsin; Tsai, Yi-Wei; Liu, Wen-Chung; Chih, Yu-Chieh; Chang, Shih-Lin

    2017-07-01

    We report a high-resolution and high-efficiency monochromator with energy resolution, ΔE/E∼2.08*10-7, utilizing a hard x-ray single-mode Fabry-Perot (FP) resonator at Laue incidence at 14.4388 keV. Instead of using multiple-crystal diffraction via several asymmetric-cut crystals, a 3 meV single-peak is generated from the interference of a Si-made two-plate cavity with a thickness of 70 μm and a gap of 45 μm, where a (0-40) Laue reflection is used to excite the backreflection (12 4 0) for the enhancement of the FP efficiency. Due to the large angular acceptance of (12 4 0) and (0-40), the energy tunability can be achieved by changing the incident angle into the resonator. The application of x-ray resonators at Laue incidence as a monochromator can be further implemented to x-ray optics.

  11. Multi-pitch Estimation using Semidefinite Programming

    DEFF Research Database (Denmark)

    Jensen, Tobias Lindstrøm; Vandenberghe, Lieven

    2017-01-01

    Multi-pitch estimation concerns the problem of estimating the fundamental frequencies (pitches) and amplitudes/phases of multiple superimposed harmonic signals with application in music, speech, vibration analysis etc. In this paper we formulate a complex-valued multi-pitch estimator via a semide......Multi-pitch estimation concerns the problem of estimating the fundamental frequencies (pitches) and amplitudes/phases of multiple superimposed harmonic signals with application in music, speech, vibration analysis etc. In this paper we formulate a complex-valued multi-pitch estimator via...... a semidefinite programming representation of an atomic decomposition over a continuous dictionary of complex exponentials and extend this to real-valued data via a real semidefinite pro-ram with the same dimensions (i.e. half the size). We further impose a continuous frequency constraint naturally occurring from...... assuming a Nyquist sampled signal by adding an additional semidefinite constraint. We show that the proposed estimator has superior performance compared to state- of-the-art methods for separating two closely spaced fundamentals and approximately achieves the asymptotic Cramér-Rao lower bound....

  12. On the Perceptual Subprocess of Absolute Pitch

    Directory of Open Access Journals (Sweden)

    Seung-Goo Kim

    2017-10-01

    Full Text Available Absolute pitch (AP is the rare ability of musicians to identify the pitch of tonal sound without external reference. While there have been behavioral and neuroimaging studies on the characteristics of AP, how the AP is implemented in human brains remains largely unknown. AP can be viewed as comprising of two subprocesses: perceptual (processing auditory input to extract a pitch chroma and associative (linking an auditory representation of pitch chroma with a verbal/non-verbal label. In this review, we focus on the nature of the perceptual subprocess of AP. Two different models on how the perceptual subprocess works have been proposed: either via absolute pitch categorization (APC or based on absolute pitch memory (APM. A major distinction between the two views is that whether the AP uses unique auditory processing (i.e., APC that exists only in musicians with AP or it is rooted in a common phenomenon (i.e., APM, only with heightened efficiency. We review relevant behavioral and neuroimaging evidence that supports each notion. Lastly, we list open questions and potential ideas to address them.

  13. High power wavelength linearly swept mode locked fiber laser for OCT imaging.

    Science.gov (United States)

    Liu, George Y; Mariampillai, Adrian; Standish, Beau A; Munce, Nigel R; Gu, Xijia; Vitkin, I Alex

    2008-09-01

    We report a long coherence length, high power, and wide tuning range wavelength linearly swept fiber mode-locked laser based on polygon scanning filters. An output power of 52.6 mW with 112 nm wavelength tuning range at 62.6 kHz sweeping rate has been achieved. The coherence length is long enough to enable imaging over 8.1 mm depth when the sensitivity decreases by 8.7 dB (1/e(2)). The Fourier components are still distinguishable when the ranging depth exceeds 15 mm, which corresponds to 30 mm optical path difference in air. The parameters that are critical to OCT imaging quality such as polygon filter linewidth, the laser coherence length, output power, axial resolution and the Fourier sensitivity have been investigated theoretically and experimentally. Since the wavelength is swept linearly with time, an analytical approach has been developed for transforming the interference signal from equidistant spacing in wavelength to equidistant spacing in frequency. Axial resolution of 7.9 microm in air has been achieved experimentally that approaches the theoretical limit.

  14. High Resolution Switching Mode Inductance-to-Frequency Converter with Temperature Compensationti

    Science.gov (United States)

    Matko, Vojko; Milanović, Miro

    2014-01-01

    This article proposes a novel method for the temperature-compensated inductance-to-frequency converter with a single quartz crystal oscillating in the switching oscillating circuit to achieve better temperature stability of the converter. The novelty of this method lies in the switching-mode converter, the use of additionally connected impedances in parallel to the shunt capacitances of the quartz crystal, and two inductances in series to the quartz crystal. This brings a considerable reduction of the temperature influence of AT-cut crystal frequency change in the temperature range between 10 and 40 °C. The oscillator switching method and the switching impedances connected to the quartz crystal do not only compensate for the crystal's natural temperature characteristics but also any other influences on the crystal such as ageing as well as from other oscillating circuit elements. In addition, the method also improves frequency sensitivity in inductance measurements. The experimental results show that through high temperature compensation improvement of the quartz crystal characteristics, this switching method theoretically enables a 2 pH resolution. It converts inductance to frequency in the range of 85–100 μH to 2–560 kHz. PMID:25325334

  15. High resolution switching mode inductance-to-frequency converter with temperature compensation.

    Science.gov (United States)

    Matko, Vojko; Milanović, Miro

    2014-10-16

    This article proposes a novel method for the temperature-compensated inductance-to-frequency converter with a single quartz crystal oscillating in the switching oscillating circuit to achieve better temperature stability of the converter. The novelty of this method lies in the switching-mode converter, the use of additionally connected impedances in parallel to the shunt capacitances of the quartz crystal, and two inductances in series to the quartz crystal. This brings a considerable reduction of the temperature influence of AT-cut crystal frequency change in the temperature range between 10 and 40 °C. The oscillator switching method and the switching impedances connected to the quartz crystal do not only compensate for the crystal's natural temperature characteristics but also any other influences on the crystal such as ageing as well as from other oscillating circuit elements. In addition, the method also improves frequency sensitivity in inductance measurements. The experimental results show that through high temperature compensation improvement of the quartz crystal characteristics, this switching method theoretically enables a 2 pH resolution. It converts inductance to frequency in the range of 85-100 µH to 2-560 kHz.

  16. High power burst-mode optical parametric amplifier with arbitrary pulse selection.

    Science.gov (United States)

    Pergament, M; Kellert, M; Kruse, K; Wang, J; Palmer, G; Wissmann, L; Wegner, U; Lederer, M J

    2014-09-08

    We present results from a unique burst-mode femtosecond non-collinear optical parametric amplifier (NOPA) under development for the optical - x-ray pump-probe experiments at the European X-Ray Free-Electron Laser Facility. The NOPA operates at a burst rate of 10 Hz, a duty cycle of 2.5% and an intra-burst repetition rate of up to 4.5 MHz, producing high fidelity 15 fs pulses at a center wavelength of 810 nm. Using dispersive amplification filtering of the super-continuum seed pulses allows for selectable pulse duration up to 75 fs, combined with a tuning range in excess of 100 nm whilst remaining nearly transform limited. At an intra-burst rate of 188 kHz the single pulse energy from two sequential NOPA stages reached 180 µJ, corresponding to an average power of 34W during the burst. Acousto- and electro-optic switching techniques enable the generation of transient free bursts of required length and the selection of arbitrary pulse sequences inside the burst.

  17. MHD stability analysis and global mode identification preparing for high beta operation in KSTAR

    Science.gov (United States)

    Park, Y. S.; Sabbagh, S. A.; Berkery, J. W.; Jiang, Y.; Ahn, J. H.; Han, H. S.; Bak, J. G.; Park, B. H.; Jeon, Y. M.; Kim, J.; Hahn, S. H.; Lee, J. H.; Ko, J. S.; in, Y. K.; Yoon, S. W.; Oh, Y. K.; Wang, Z.; Glasser, A. H.

    2017-10-01

    H-mode plasma operation in KSTAR has surpassed the computed n = 1 ideal no-wall stability limit in discharges exceeding several seconds in duration. The achieved high normalized beta plasmas are presently limited by resistive tearing instabilities rather than global kink/ballooning or RWMs. The ideal and resistive stability of these plasmas is examined by using different physics models. The observed m/ n = 2/1 tearing stability is computed by using the M3D-C1 code, and by the resistive DCON code. The global MHD stability modified by kinetic effects is examined using the MISK code. Results from the analysis explain the stabilization of the plasma above the ideal MHD no-wall limit. Equilibrium reconstructions used include the measured kinetic profiles and MSE data. In preparation for plasma operation at higher beta utilizing the planned second NBI system, three sets of 3D magnetic field sensors have been installed and will be used for RWM active feedback control. To accurately determine the dominant n-component produced by low frequency unstable RWMs, an algorithm has been developed that includes magnetic sensor compensation of the prompt applied field and the field from the induced current on the passive conductors. Supported by US DOE Contracts DE-FG02-99ER54524 and DE-SC0016614.

  18. Colorimetry and SERS dual-mode detection of telomerase activity: combining rapid screening with high sensitivity.

    Science.gov (United States)

    Zong, Shenfei; Wang, Zhuyuan; Chen, Hui; Hu, Guohua; Liu, Min; Chen, Peng; Cui, Yiping

    2014-01-01

    As an important biomarker and therapeutic target, telomerase has attracted considerable attention concerning its detection and monitoring. Here, we present a colorimetry and surface enhanced Raman scattering (SERS) dual-mode telomerase activity detection method, which has several distinctive advantages. First, colorimetric functionality allows rapid preliminary discrimination of telomerase activity by the naked eye. Second, the employment of SERS technique results in greatly improved detection sensitivity. Third, the combination of colorimetry and SERS into one detection system can ensure highly efficacious and sensitive screening of numerous samples. Besides, the avoidance of polymerase chain reaction (PCR) procedures further guarantees fine reliability and simplicity. Generally, the presented method is realized by an "elongate and capture" procedure. To be specific, gold nanoparticles modified with Raman molecules and telomeric repeat complementary oligonucleotide are employed as the colorimetric-SERS bifunctional reporting nanotag, while magnetic nanoparticles functionalized with telomerase substrate oligonucleotide are used as the capturing substrate. Telomerase can synthesize and elongate telomeric repeats onto the capturing substrate. The elongated telomeric repeats subsequently facilitate capturing of the reporting nanotag via hybridization between telomeric repeat and its complementary strand. The captured nanotags can cause a significant difference in the color and SERS intensity of the magnetically separated sediments. Thus both the color and SERS can be used as indicators of the telomerase activity. With fast screening ability and outstanding sensitivity, we anticipate that this method would greatly promote practical application of telomerase-based early-stage cancer diagnosis.

  19. Small-signal analysis of ultra-high-speed 30 GHz VCSELs using an advanced multi-mode approach

    Science.gov (United States)

    Hamad, Wissam; Bou Sanayeh, Marwan; Hamad, Hassan; Hamad, Mustapha; Georges, Semaan; Hofmann, Werner

    2017-05-01

    Vertical-cavity surface-emitting lasers (VCSELs) have emerged as a pioneering solution for many high-speed data communication challenges. Therefore, higher bandwidth optical interconnects with data rates in the range of 100 Gbit/s require directly modulated VCSELs with ultimate speed ratings. The small-signal modulation response of a VCSEL can be isolated from the entire system, thus providing accurate information on the intrinsic laser dynamics. Until now, it is assumed that the dynamic behavior of oxide-confined multi-mode VCSELs can be fully modeled using the single-mode rate equations developed for edge-emitters, even though the deviation between the single-mode based model and the measured data is substantially large. Using an advanced theoretical approach, rate equations for multi-mode VCSELs were developed and the small-signal modulation response of ultra-high speed devices with split carrier reservoirs corresponding with the resonating modes were analyzed. Based on this theoretical work, and including gain compression in the model, the analyzed VCSELs showed modulation bandwidth around and exceeding 30 GHz. The common set of figures of merit is extended consistently to explain dynamic properties caused by the coupling of the different reservoirs. Furthermore, beside damping and relaxation oscillation frequency, the advanced model, with gain compression included, can reveal information on the photon lifetime and highlights high-speed effects such as reduced damping in VCSELs due to a negative gain compression factor.

  20. Pitch Memory in Nonmusicians and Musicians: Revealing Functional Differences Using Transcranial Direct Current Stimulation.

    Science.gov (United States)

    Schaal, N K; Krause, V; Lange, K; Banissy, M J; Williamson, V J; Pollok, B

    2015-09-01

    For music and language processing, memory for relative pitches is highly important. Functional imaging studies have shown activation of a complex neural system for pitch memory. One region that has been shown to be causally involved in the process for nonmusicians is the supramarginal gyrus (SMG). The present study aims at replicating this finding and at further examining the role of the SMG for pitch memory in musicians. Nonmusicians and musicians received cathodal transcranial direct current stimulation (tDCS) over the left SMG, right SMG, or sham stimulation, while completing a pitch recognition, pitch recall, and visual memory task. Cathodal tDCS over the left SMG led to a significant decrease in performance on both pitch memory tasks in nonmusicians. In musicians, cathodal stimulation over the left SMG had no effect, but stimulation over the right SMG impaired performance on the recognition task only. Furthermore, the results show a more pronounced deterioration effect for longer pitch sequences indicating that the SMG is involved in maintaining higher memory load. No stimulation effect was found in both groups on the visual control task. These findings provide evidence for a causal distinction of the left and right SMG function in musicians and nonmusicians. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  1. The SEMATECH Berkeley MET: extending EUV learning to 16-nm half pitch

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Christopher N.; Baclea-an, Lorie Mae; Denham, Paul E.; George, Simi; Goldberg, Kenneth A.; Jones, Michael; Smith, Nathan; Wallow, Thomas; Montgomery, Warren; Naulleau, Patrick P.

    2011-03-18

    Several high-performing resists identified in the past two years have been exposed at the 0.3-numerical-aperture (NA) SEMATECH Berkeley Microfield Exposure Tool (BMET) with an engineered dipole illumination optimized for 18-nm half pitch. Five chemically amplified platforms were found to support 20-nm dense patterning at a film thickness of approximately 45 nm. At 19-nm half pitch, however, scattered bridging kept all of these resists from cleanly resolving larger areas of dense features. At 18-nm half pitch, none of the resists were are able to cleanly resolve a single line within a bulk pattern. With this same illumination a directly imageable metal oxide hardmask showed excellent performance from 22-nm half pitch to 17-nm half pitch, and good performance at 16-nm half pitch, closely following the predicted aerial image contrast. This indicates that observed limitations of the chemically amplified resists are indeed coming from the resist and not from a shortcoming of the exposure tool. The imageable hardmask was also exposed using a Pseudo Phase-Shift-Mask technique and achieved clean printing of 15-nm half pitch lines and modulation all the way down to the theoretical 12.5-nm resolution limit of the 0.3-NA SEMATECH BMET.

  2. Thermal Reactivity and Structure of Carbonized Binder Pitches

    OpenAIRE

    Madshus, Stian

    2005-01-01

    Pitches are used on a large scale in the manufacture of carbon anodes for the production of primary aluminium. The role of the pitch is to act as a binder between the petroleum coke grains. The structure of the carbonized pitch binder (pitch coke) has an important impact on the overall performance of the anode. Even though the binder pitch is the minor constituent in an anode, it is impossible to make a good quality anode without a good quality binder pitch. Pitch is an extremely complex ...

  3. Controllable damping of high-Q violin modes in fused silica suspension fibers

    Science.gov (United States)

    Dmitriev, A. V.; Mescheriakov, S. D.; Tokmakov, K. V.; Mitrofanov, V. P.

    2010-01-01

    Fused silica fiber suspension of the test masses will be used in the interferometric gravitational wave detectors of the next generation. This allows a significant reduction of losses in the suspension and thermal noise associated with the suspension. Unfortunately, unwanted violin modes may be accidentally excited in the suspension fibers. The Q-factor of the violin modes also exceeds 108. They have a ring-down time that is too long and may complicate the stable control of the interferometer. Results of the investigation of a violin mode active damping system are described. An original sensor and actuator were especially developed to realize the effective coupling of a thin, optically transparent, non-conducting fused silica fiber with an electric circuit. The damping system allowed the changing of the violin mode's damping rate over a wide range.

  4. High Performance Spatial Filter Array Based on Signal Mode Fiber Bundle Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Loveraging on Agiltron's experience in optical fiber components, Agiltron proposed a coherent single-mode fiber (SMF) spatial filter array (SFA) with a gradient...

  5. High Fidelity Multi-Mode Hyperspectral Multispectral Imager with Programmable Spectral Resolution Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase II proposal introduces a fast multi-mode hyperspectral-multispectral (MM-HS-MS) sensor with programmable spectral resolution. The sensor brings the...

  6. Controllable damping of high-Q violin modes in fused silica suspension fibers

    Energy Technology Data Exchange (ETDEWEB)

    Dmitriev, A V; Mescheriakov, S D; Mitrofanov, V P [Faculty of Physics, Moscow State University, Moscow 119991 (Russian Federation); Tokmakov, K V, E-mail: dmitriev@hbar.phys.msu.r, E-mail: mitr@hbar.phys.msu.r [Present address: Department of Physics, SUPA, University of Strathclyde, Glasgow G4 0NG (United Kingdom)

    2010-01-21

    Fused silica fiber suspension of the test masses will be used in the interferometric gravitational wave detectors of the next generation. This allows a significant reduction of losses in the suspension and thermal noise associated with the suspension. Unfortunately, unwanted violin modes may be accidentally excited in the suspension fibers. The Q-factor of the violin modes also exceeds 10{sup 8}. They have a ring-down time that is too long and may complicate the stable control of the interferometer. Results of the investigation of a violin mode active damping system are described. An original sensor and actuator were especially developed to realize the effective coupling of a thin, optically transparent, non-conducting fused silica fiber with an electric circuit. The damping system allowed the changing of the violin mode's damping rate over a wide range.

  7. Survey of degradation modes of candidate materials for high-level radioactive-waste disposal containers

    Energy Technology Data Exchange (ETDEWEB)

    Farmer, J.C.; Van Konynenburg, R.A.; McCright, R.D. (Lawrence Livermore National Lab., CA (USA)); Gdowski, G.E. (Science and Engineering Associates, Inc., Pleasanton, CA (USA))

    1988-06-01

    Three copper-based alloys, CDA 102 (oxygen-free, high-purity copper), CDA 613 (aluminum bronze), and CDA 715 (Cu-30Ni), are candidates for the fabrication of high-level radioactive-waste disposal containers. Waste will include spent fuel assemblies from reactors as well as borosilicate glass, and will be sent to the prospective repository site at Yucca Mountain in Nye County, Nevada. The decay of radionuclides will result in the generation of substantial heat and in fluxes of gamma radiation outside the containers. In this environment, container materials might degrade by atmospheric oxidation, general aqueous phase corrosion, localized corrosion (LC), and stress corrosion cracking (SCC). This volume is a critical survey of available data on pitting and crevice corrosion of the copper-based candidates. Pitting and crevice corrosion are two of the most common forms of LC of these materials. Data on the SCC of these alloys is surveyed in Volume 4. Pitting usually occurs in water that contains low concentrations of bicarbonate and chloride anions, such as water from Well J-13 at the Nevada Test Site. Consequently, this mode of degradation might occur in the repository environment. Though few quantitative data on LC were found, a tentative ranking based on pitting corrosion, local dealloying, crevice corrosion, and biofouling is presented. CDA 102 performs well in the categories of pitting corrosion, local dealloying, and biofouling, but susceptibility to crevice corrosion diminishes its attractiveness as a candidate. The cupronickel alloy, CDA 715, probably has the best overall resistance to such localized forms of attack. 123 refs., 11 figs., 3 tabs.

  8. Survey of degradation modes of candidate materials for high-level radioactive-waste disposal containers

    Energy Technology Data Exchange (ETDEWEB)

    Farmer, J.C.; Van Konynenburg, R.A.; McCright, R.D. (Lawrence Livermore National Lab., CA (USA)); Bullen, D.B. (Science and Engineering Associates, Inc., Pleasanton, CA (USA))

    1988-04-01

    Three iron- to nickel-based austenitic alloys (Types 304L and 316L stainless steels and Alloy 825) are being considered as candidate materials for the fabrication of high-level radioactive-waste containers. Waste will include fuel assemblies from reactors as well as high-level waste in borosilicate glass forms, and will be sent to the prospective repository at Yucca Mountain, Nevada. The decay of radionuclides in the repository will result in the generation of substantial heat and in fluences of gamma radiation. Container materials may undergo any of several modes of degradation in this environment, including atmospheric oxidation; uniform aqueous phase corrosion; pitting; crevice corrosion; sensitization and intergranular stress corrosion cracking (IGSCC); and transgranular stress corrosion cracking (TGSCC). This report is an analysis of data relevant to the pitting, crevice corrosion, and stress corrosion cracking (SCC) of the three austenitic candidate alloys. The candidates are compared in terms of their susceptibilities to these forms of corrosion. Although all three candidates have demonstrated pitting and crevice corrosion in chloride-containing environments, Alloy 825 has the greatest resistance to these types of localized corrosion (LC); such resistance is important because pits can penetrate the metal and serve as crack initiation sites. Both Types 304L and 316L stainless steels are susceptible to SCC in acidic chloride media. In contrast, SCC has not been documented in Alloy 825 under comparable conditions. Gamma radiation has been found to enhance SCC in Types 304 and 304L stainless steels, but it has no detectable effect on the resistance of Alloy 825 to SCC. Furthermore, while the effects of microbiologically induced corrosion have been observed for 300-series stainless steels, nickel-based alloys such as Alloy 825 seem to be immune to such problems. 211 refs., 49 figs., 10 tabs.

  9. Coupling single NV-centres to high-Q whispering gallery modes of a preselected frequency-matched microresonator

    Energy Technology Data Exchange (ETDEWEB)

    Schietinger, Stefan; Benson, Oliver [Nano-Optics, Institute of Physics, Humboldt-Universitaet zu Berlin, Hausvogteiplatz 5-7, D-10117 Berlin (Germany)], E-mail: schietinger@physik.hu-berlin.de

    2009-06-14

    In this paper, we report the controlled coupling of fluorescence from a single NV-centre in a single nanodiamond to the high-Q modes of a preselected microsphere. Microspheres from an ensemble with a finite size distribution can be characterized precisely via white light Mie-scattering. The mode spectrum of individual spheres can be determined with high precision. A sphere with an appropriate spectrum can be selected, and a nanodiamond containing a single NV-centre can be coupled to it. The spectral position of the calculated lowest order whispering gallery modes are found to be in very good agreement with the experimentally observed resonances of the coupled fluorescence from the single NV-re.

  10. Differential mode EMI filter design for ultra high efficiency partial parallel isolated full-bridge boost converter

    DEFF Research Database (Denmark)

    Makda, Ishtiyaq Ahmed; Nymand, M.

    2013-01-01

    This paper presents a practical method to design a Differential Mode EMI filter for fuel cell powered isolated full bridge dc-dc boost converter. As the input voltage of such converter is inherently low with very high dc and ripple currents and since the EMI limits also does not change for such a......This paper presents a practical method to design a Differential Mode EMI filter for fuel cell powered isolated full bridge dc-dc boost converter. As the input voltage of such converter is inherently low with very high dc and ripple currents and since the EMI limits also does not change...... for such application, it calls for a carefully optimized EMI filter which is designed and implemented in this work. Moreover, the negative input impedance of the regulated converter is extremely low; well-designed filter damping branch is also included. Differential mode noise is analyzed analytically for a 3KW/400V...

  11. 80 GHz AlGaInAs/InP colliding-pulse mode-locked laser with high pulse power

    Science.gov (United States)

    Zhao, Pengchao; Liu, Anjin; Zheng, Wanhua

    2016-12-01

    We theoretically analyze the impact of a saturable absorber (SA) length on the pulse power of a semiconductor mode-locked laser and find that in the range of the SA length from 1.5 to 7%, a laser with a longer SA can generate pulses with a higher power. Based on the simulation, we demonstrate a colliding-pulse mode-locked laser with an 80 µm SA. The device generates pulses at 80 GHz, with a pulse width of 1.75 ps, peak power of 188 mW, pulse energy of 0.33 pJ, and time-bandwidth product of 0.51. The results provide new possibilities for the design of high-repetition frequency high-pulse power mode-locked lasers.

  12. High-power single spatial mode AlGaAs channeled-substrate-planar semiconductor diode lasers for spaceborne communications

    Science.gov (United States)

    Connolly, J. C.; Carlin, D. B.; Ettenberg, M.

    1989-01-01

    A high power single spatial mode channeled substrate planar AlGaAs semiconductor diode laser was developed. The emission wavelength was optimized at 860 to 880 nm. The operating characteristics (power current, single spatial mode behavior, far field radiation patterns, and spectral behavior) and results of computer modeling studies on the performance of the laser are discussed. Reliability assessment at high output levels is included. Performance results on a new type of channeled substrate planar diode laser incorporating current blocking layers, grown by metalorganic chemical vapor deposition, to more effectively focus the operational current to the lasing region was demonstrated. The optoelectronic behavior and fabrication procedures for this new diode laser are discussed. The highlights include single spatial mode devices with up to 160 mW output at 8600 A, and quantum efficiencies of 70 percent (1 W/amp) with demonstrated operating lifetimes of 10,000 h at 50 mW.

  13. Access to a New Plasma Edge State with High Density and Pressures using Quiescent H-mode

    Energy Technology Data Exchange (ETDEWEB)

    Solomon, Wayne M. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Snyder, P. B. [General Atomics, San Diego, CA (United States); Burrell, K. H. [General Atomics, San Diego, CA (United States); Fenstermacher, M. E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Garofalo, A. M. [General Atomics, San Diego, CA (United States); Grierson, B. A. [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Loarte, A. [ITER Organization, St. Paul Lez Durance (France); McKee, G. R. [Univ. of Wisconsin, Madison, WI (United States); Nazikian, R [Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Osborne, T. H. [General Atomics, San Diego, CA (United States)

    2014-07-01

    A path to a new high performance regime has been discovered in tokamaks that could improve the attractiveness of a fusion reactor. Experiments on DIII-D using a quiescent H-mode edge have navigated a valley of improved edge peeling-ballooning stability that opens up with strong plasma shaping at high density, leading to a doubling of the edge pressure over standard edge localized mode (ELM)ing H-mode at these parameters. The thermal energy confinement time increases both as a result of the increased pedestal height and improvements in the core transport and reduced low-k turbulence. Calculations of the pedestal height and width as a function of density using constraints imposed by peeling-ballooning and kinetic-ballooning theory are in quantitative agreement with the measurements.

  14. Modeling of Beams’ Multiple-Contact Mode with an Application in the Design of a High-g Threshold Microaccelerometer

    Directory of Open Access Journals (Sweden)

    Kai Li

    2011-05-01

    Full Text Available Beam’s multiple-contact mode, characterized by multiple and discrete contact regions, non-uniform stoppers’ heights, irregular contact sequence, seesaw-like effect, indirect interaction between different stoppers, and  complex coupling relationship between loads and deformation is studied. A novel analysis method and a novel high speed calculation model are developed for multiple-contact mode under mechanical load and electrostatic load, without limitations on stopper height and distribution, providing the beam has stepped or curved shape. Accurate values of deflection, contact load, contact region and so on are obtained directly, with a subsequent validation by CoventorWare. A new concept design of high-g threshold microaccelerometer based on multiple-contact mode is presented, featuring multiple acceleration thresholds of one sensitive component and consequently small sensor size.

  15. Modal–Physical Hybrid System Identification of High-rise Building via Subspace and Inverse-Mode Methods

    Directory of Open Access Journals (Sweden)

    Kohei Fujita

    2017-08-01

    Full Text Available A system identification (SI problem of high-rise buildings is investigated under restricted data environments. The shear and bending stiffnesses of a shear-bending model (SB model representing the high-rise buildings are identified via the smart combination of the subspace and inverse-mode methods. Since the shear and bending stiffnesses of the SB model can be identified in the inverse-mode method by using the lowest mode of horizontal displacements and floor rotation angles, the lowest mode of the objective building is identified first by using the subspace method. Identification of the lowest mode is performed by using the amplitude of transfer functions derived in the subspace method. Considering the resolution in measuring the floor rotation angles in lower stories, floor rotation angles in most stories are predicted from the floor rotation angle at the top floor. An empirical equation of floor rotation angles is proposed by investigating those for various building models. From the viewpoint of application of the present SI method to practical situations, a non-simultaneous measurement system is also proposed. In order to investigate the reliability and accuracy of the proposed SI method, a 10-story building frame subjected to micro-tremor is examined.

  16. Automated aberration compensation in high numerical aperture systems for arbitrary laser modes (Conference Presentation)

    Science.gov (United States)

    Hering, Julian; Waller, Erik H.; von Freymann, Georg

    2017-02-01

    Since a large number of optical systems and devices are based on differently shaped focal intensity distributions (point-spread-functions, PSF), the PSF's quality is crucial for the application's performance. E.g., optical tweezers, optical potentials for trapping of ultracold atoms as well as stimulated-emission-depletion (STED) based microscopy and lithography rely on precisely controlled intensity distributions. However, especially in high numerical aperture (NA) systems, such complex laser modes are easily distorted by aberrations leading to performance losses. Although different approaches addressing phase retrieval algorithms have been recently presented[1-3], fast and automated aberration compensation for a broad variety of complex shaped PSFs in high NA systems is still missing. Here, we report on a Gerchberg-Saxton[4] based algorithm (GSA) for automated aberration correction of arbitrary PSFs, especially for high NA systems. Deviations between the desired target intensity distribution and the three-dimensionally (3D) scanned experimental focal intensity distribution are used to calculate a correction phase pattern. The target phase distribution plus the correction pattern are displayed on a phase-only spatial-light-modulator (SLM). Focused by a high NA objective, experimental 3D scans of several intensity distributions allow for characterization of the algorithms performance: aberrations are reliably identified and compensated within less than 10 iterations. References 1. B. M. Hanser, M. G. L. Gustafsson, D. A. Agard, and J. W. Sedat, "Phase-retrieved pupil functions in wide-field fluorescence microscopy," J. of Microscopy 216(1), 32-48 (2004). 2. A. Jesacher, A. Schwaighofer, S. Frhapter, C. Maurer, S. Bernet, and M. Ritsch-Marte, "Wavefront correction of spatial light modulators using an optical vortex image," Opt. Express 15(9), 5801-5808 (2007). 3. A. Jesacher and M. J. Booth, "Parallel direct laser writing in three dimensions with spatially dependent

  17. A Bayesian Account of Vocal Adaptation to Pitch-Shifted Auditory Feedback.

    Directory of Open Access Journals (Sweden)

    Richard H R Hahnloser

    Full Text Available Motor systems are highly adaptive. Both birds and humans compensate for synthetically induced shifts in the pitch (fundamental frequency of auditory feedback stemming from their vocalizations. Pitch-shift compensation is partial in the sense that large shifts lead to smaller relative compensatory adjustments of vocal pitch than small shifts. Also, compensation is larger in subjects with high motor variability. To formulate a mechanistic description of these findings, we adapt a Bayesian model of error relevance. We assume that vocal-auditory feedback loops in the brain cope optimally with known sensory and motor variability. Based on measurements of motor variability, optimal compensatory responses in our model provide accurate fits to published experimental data. Optimal compensation correctly predicts sensory acuity, which has been estimated in psychophysical experiments as just-noticeable pitch differences. Our model extends the utility of Bayesian approaches to adaptive vocal behaviors.

  18. Sensing Performance Analysis on Quartz Tuning Fork-Probe at the High Order Vibration Mode for Multi-Frequency Scanning Probe Microscopy

    Directory of Open Access Journals (Sweden)

    Xiaofei Zhang

    2018-01-01

    Full Text Available Multi-frequency scanning near-field optical microscopy, based on a quartz tuning fork-probe (QTF-p sensor using the first two orders of in-plane bending symmetrical vibration modes, has recently been developed. This method can simultaneously achieve positional feedback (based on the 1st in-plane mode called the low mode and detect near-field optically induced forces (based on the 2nd in-plane mode called the high mode. Particularly, the high mode sensing performance of the QTF-p is an important issue for characterizing the tip-sample interactions and achieving higher resolution microscopic imaging but the related researches are insufficient. Here, we investigate the vibration performance of QTF-p at high mode based on the experiment and finite element method. The frequency spectrum characteristics are obtained by our homemade laser Doppler vibrometer system. The effects of the properties of the connecting glue layer and the probe features on the dynamic response of the QTF-p sensor at the high mode are investigated for optimization design. Finally, compared with the low mode, an obvious improvement of quality factor, of almost 50%, is obtained at the high mode. Meanwhile, the QTF-p sensor has a high force sensing sensitivity and a large sensing range at the high mode, indicating a broad application prospect for force sensing.

  19. Sensing Performance Analysis on Quartz Tuning Fork-Probe at the High Order Vibration Mode for Multi-Frequency Scanning Probe Microscopy.

    Science.gov (United States)

    Zhang, Xiaofei; Gao, Fengli; Li, Xide

    2018-01-24

    Multi-frequency scanning near-field optical microscopy, based on a quartz tuning fork-probe (QTF-p) sensor using the first two orders of in-plane bending symmetrical vibration modes, has recently been developed. This method can simultaneously achieve positional feedback (based on the 1st in-plane mode called the low mode) and detect near-field optically induced forces (based on the 2nd in-plane mode called the high mode). Particularly, the high mode sensing performance of the QTF-p is an important issue for characterizing the tip-sample interactions and achieving higher resolution microscopic imaging but the related researches are insufficient. Here, we investigate the vibration performance of QTF-p at high mode based on the experiment and finite element method. The frequency spectrum characteristics are obtained by our homemade laser Doppler vibrometer system. The effects of the properties of the connecting glue layer and the probe features on the dynamic response of the QTF-p sensor at the high mode are investigated for optimization design. Finally, compared with the low mode, an obvious improvement of quality factor, of almost 50%, is obtained at the high mode. Meanwhile, the QTF-p sensor has a high force sensing sensitivity and a large sensing range at the high mode, indicating a broad application prospect for force sensing.

  20. Sensorimotor Mismapping in Poor-pitch Singing.

    Science.gov (United States)

    He, Hao; Zhang, Wei-Dong

    2017-09-01

    This study proposes that there are two types of sensorimotor mismapping in poor-pitch singing: erroneous mapping and no mapping. We created operational definitions for the two types of mismapping based on the precision of pitch-matching and predicted that in the two types of mismapping, phonation differs in terms of accuracy and the dependence on the articulation consistency between the target and the intended vocal action. The study aimed to test this hypothesis by examining the reliability and criterion-related validity of the operational definitions. A within-subject design was used in this study. Thirty-two participants identified as poor-pitch singers were instructed to vocally imitate pure tones and to imitate their own vocal recordings with the same articulation as self-targets and with different articulation from self-targets. Definitions of the types of mismapping were demonstrated to be reliable with the split-half approach and to have good criterion-related validity with findings that pitch-matching with no mapping was less accurate and more dependent on the articulation consistency between the target and the intended vocal action than pitch-matching with erroneous mapping was. Furthermore, the precision of pitch-matching was positively associated with its accuracy and its dependence on articulation consistency when mismapping was analyzed on a continuum. Additionally, the data indicated that the self-imitation advantage was a function of articulation consistency. Types of sensorimotor mismapping lead to pitch-matching that differs in accuracy and its dependence on the articulation consistency between the target and the intended vocal action. Additionally, articulation consistency produces the self-advantage. Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.

  1. Colorimetry and SERS dual-mode detection of telomerase activity: combining rapid screening with high sensitivity

    Science.gov (United States)

    Zong, Shenfei; Wang, Zhuyuan; Chen, Hui; Hu, Guohua; Liu, Min; Chen, Peng; Cui, Yiping

    2014-01-01

    As an important biomarker and therapeutic target, telomerase has attracted considerable attention concerning its detection and monitoring. Here, we present a colorimetry and surface enhanced Raman scattering (SERS) dual-mode telomerase activity detection method, which has several distinctive advantages. First, colorimetric functionality allows rapid preliminary discrimination of telomerase activity by the naked eye. Second, the employment of SERS technique results in greatly improved detection sensitivity. Third, the combination of colorimetry and SERS into one detection system can ensure highly efficacious and sensitive screening of numerous samples. Besides, the avoidance of polymerase chain reaction (PCR) procedures further guarantees fine reliability and simplicity. Generally, the presented method is realized by an ``elongate and capture'' procedure. To be specific, gold nanoparticles modified with Raman molecules and telomeric repeat complementary oligonucleotide are employed as the colorimetric-SERS bifunctional reporting nanotag, while magnetic nanoparticles functionalized with telomerase substrate oligonucleotide are used as the capturing substrate. Telomerase can synthesize and elongate telomeric repeats onto the capturing substrate. The elongated telomeric repeats subsequently facilitate capturing of the reporting nanotag via hybridization between telomeric repeat and its complementary strand. The captured nanotags can cause a significant difference in the color and SERS intensity of the magnetically separated sediments. Thus both the color and SERS can be used as indicators of the telomerase activity. With fast screening ability and outstanding sensitivity, we anticipate that this method would greatly promote practical application of telomerase-based early-stage cancer diagnosis.As an important biomarker and therapeutic target, telomerase has attracted considerable attention concerning its detection and monitoring. Here, we present a colorimetry and

  2. Three-mode factor analysis of data on retention in normal-phase high-performance liquid chromatography

    NARCIS (Netherlands)

    Ligny, C.L. de; Spanjer, M.C.; Houwelingen, J.C. van; Weesie, H.M.

    1984-01-01

    It is shown that the Snyder equation is not quite satisfactory for fitting retention data in normal-phase high-performance liquid chromatography (HPLC) on chemically bonded phases. This equation is a special case of the mathematical—statistical three-mode factor analysis model. This model, in its

  3. Mixed Stimulus-Induced Mode Selection in Neural Activity Driven by High and Low Frequency Current under Electromagnetic Radiation

    Directory of Open Access Journals (Sweden)

    Lulu Lu

    2017-01-01

    Full Text Available The electrical activities of neurons are dependent on the complex electrophysiological condition in neuronal system, the three-variable Hindmarsh-Rose (HR neuron model is improved to describe the dynamical behaviors of neuronal activities with electromagnetic induction being considered, and the mode transition of electrical activities in neuron is detected when external electromagnetic radiation is imposed on the neuron. In this paper, different types of electrical stimulus impended with a high-low frequency current are imposed on new HR neuron model, and mixed stimulus-induced mode selection in neural activity is discussed in detail. It is found that mode selection of electrical activities stimulated by high-low frequency current, which also changes the excitability of neuron, can be triggered owing to adding the Gaussian white noise. Meanwhile, the mode selection of the neuron electrical activity is much dependent on the amplitude B of the high frequency current under the same noise intensity, and the high frequency response is selected preferentially by applying appropriate parameters and noise intensity. Our results provide insights into the transmission of complex signals in nerve system, which is valuable in engineering prospective applications such as information encoding.

  4. Highly compliant guided-mode resonance nanogratings: From theory to application in mechanical strain sensing

    Science.gov (United States)

    Foland, Steven J.

    This work reports the theory, design, fabrication, and characterization of highly-compliant polymer-based guided-mode resonance (GMR) grating devices. GMR devices have been widely researched in recent years for their applications in telecommunications and biosensing. The vast majority of GMR-based sensors are fabricated and characterized on rigid transparent substrates, and are designed to respond to changes in the optical properties of their surrounding media. While useful in a number of conventional sensing configurations, the applications of rigid gratings for mechanical sensing are extremely limited. To enable a GMR sensor to respond to mechanical stimuli, both the grating and its substrate must be compliant, a property inherent to the devices presented herein. An extensive toolset is required for the design of such resonant optical devices; this dissertation defines the theoretical and simulations models used for the analysis of these dynamic grating devices, and provides a clear understanding of both their strengths and limitations. These tools include a waveguide-theory based theoretical model for rapid approximation of grating resonance conditions, and finite element method (FEM) simulation for full-field solutions to Maxwell's equations. A number of challenges which arise when attempting to fabricate nanostructures on a thin polymer are also addressed, and a fabrication process is developed to enable a practical embodiment of the proposed devices. The results of this process are subwavelength titanium dioxide (TiO2) gratings embedded at the surface of compliant polydimethylsiloxane (PDMS) structures. Both a one-dimensional, membrane-embedded GMR grating for local measurement of microfluidic channel pressure, and a two-dimensional, slab-embedded GMR grating for biaxial strain detection are discussed, demonstrated, and evaluated. Additionally, potential improvements to the devices' performance and suggestions for future work are provided.

  5. Pipe leak diagnostic using high frequency piezoelectric pressure sensor and automatic selection of intrinsic mode function

    Science.gov (United States)

    Yusop, Hanafi M.; Ghazali, M. F.; Yusof, M. F. M.; Remli, M. A. Pi; Kamarulzaman, M. H.

    2017-10-01

    In a recent study, the analysis of pressure transient signals could be seen as an accurate and low-cost method for leak and feature detection in water distribution systems. Transient phenomena occurs due to sudden changes in the fluid’s propagation in pipelines system caused by rapid pressure and flow fluctuation due to events such as closing and opening valves rapidly or through pump failure. In this paper, the feasibility of the Hilbert-Huang transform (HHT) method/technique in analysing the pressure transient signals in presented and discussed. HHT is a way to decompose a signal into intrinsic mode functions (IMF). However, the advantage of HHT is its difficulty in selecting the suitable IMF for the next data postprocessing method which is Hilbert Transform (HT). This paper reveals that utilizing the application of an integrated kurtosis-based algorithm for a z-filter technique (I-Kaz) to kurtosis ratio (I-Kaz-Kurtosis) allows/contributes to/leads to automatic selection of the IMF that should be used. This technique is demonstrated on a 57.90-meter medium high-density polyethylene (MDPE) pipe installed with a single artificial leak. The analysis results using the I-Kaz-kurtosis ratio revealed/confirmed that the method can be used as an automatic selection of the IMF although the noise level ratio of the signal is low. Therefore, the I-Kaz-kurtosis ratio method is recommended as a means to implement an automatic selection technique of the IMF for HHT analysis.

  6. Influences of Dynamic Level and Pitch Register on the Vibrato Rates and Widths of Violin and Viola Players

    Science.gov (United States)

    MacLeod, Rebecca B.

    2008-01-01

    The purpose of this study was to investigate possible influences of pitch register and dynamic level on vibrato rates and widths of university and high school violin and viola players. Analysis showed that pitch register significantly affected the vibrato rates and widths of the performers. Musicians vibrated 0.32 Hz faster and approximately 26…

  7. Absolute and relative pitch: Global versus local processing of chords.

    Science.gov (United States)

    Ziv, Naomi; Radin, Shulamit

    2014-01-01

    Absolute pitch (AP) is the ability to identify or produce notes without any reference note. An ongoing debate exists regarding the benefits or disadvantages of AP in processing music. One of the main issues in this context is whether the categorical perception of pitch in AP possessors may interfere in processing tasks requiring relative pitch (RP). Previous studies, focusing mainly on melodic and interval perception, have obtained inconsistent results. The aim of the present study was to examine the effect of AP and RP separately, using isolated chords. Seventy-three musicians were categorized into four groups of high and low AP and RP, and were tested on two tasks: identifying chord types (Task 1), and identifying a single note within a chord (Task 2). A main effect of RP on Task 1 and an interaction between AP and RP in reaction times were found. On Task 2 main effects of AP and RP, and an interaction were found, with highest performance in participants with both high AP and RP. Results suggest that AP and RP should be regarded as two different abilities, and that AP may slow down reaction times for tasks requiring global processing.

  8. Assessing the relationship between high lightning events and storm mode in northern and central Alabama

    Science.gov (United States)

    Willis, Morgan Terry

    Lightning is a dangerous and deadly hazard, yet it is often underestimated by the public and excluded from severe weather watches and warnings used by the National Weather Service. Previous studies have analyzed the relationship of lightning and storm intensity in relation to severe weather, but none have analyzed this relationship across all storm modes in an area including Northern and Central Alabama. This study attempts to assess the relationship between cloud-to-ground (CG) lightning and storm mode in storm events which occurred on lightning hazard days in Northern and Central Alabama during the years of 2007 to 2011. Storm variables for analysis included lightning flash rate, aspect ratio, total convective area above 20 dBZ, maximum convective area above 40 dBZ, and percent maximum convective area. Results show that lightning flash rates vary by season and storm mode. PCA and Cluster Analysis identified a total of 5 clusters of varying lightning flash rate and convective intensity. The storm mode events include non-summer linear, an anomalous MCS associated with a triple point frontal outflow boundary, summer airmass, non-seasonal weak, and summer MCS/MCC. Information obtained during this thesis has the potential to aid forecasters and emergency managers in Northern and Central Alabama by associating lightning flash rates with storm mode characteristics observed on lightning hazard days.

  9. Chemical composition of free tropospheric aerosol for PM1 and coarse mode at the high alpine site Jungfraujoch

    Directory of Open Access Journals (Sweden)

    J. Cozic

    2008-01-01

    Full Text Available The chemical composition of submicron (fine mode and supermicron (coarse mode aerosol particles has been investigated at the Jungfraujoch high alpine research station (3580 m a.s.l., Switzerland as part of the GAW aerosol monitoring program since 1999. A clear seasonality was observed for all major components throughout the period with low concentrations in winter (predominantly free tropospheric aerosol and higher concentrations in summer (enhanced vertical transport of boundary layer pollutants. In addition, mass closure was attempted during intensive campaigns in March 2004, February–March 2005 and August 2005. Ionic, carbonaceous and non-refractory components of the aerosol were quantified as well as the PM1 and coarse mode total aerosol mass concentrations. A relatively low conversion factor of 1.8 for organic carbon (OC to particulate organic matter (OM was found in winter (February–March 2005. Organics, sulfate, ammonium, and nitrate were the major components of the fine aerosol fraction that were identified, while calcium and nitrate were the only two measured components contributing to the coarse mode. The aerosol mass concentrations for fine and coarse mode aerosol measured during the intensive campaigns were not typical of the long-term seasonality due largely to dynamical differences. Average fine and coarse mode concentrations during the intensive field campaigns were 1.7 μg m−3 and 2.4 μg m−3 in winter and 2.5 μg m−3 and 2.0 μg m−3 in summer, respectively. The mass balance of aerosols showed higher contributions of calcium and nitrate in the coarse mode during Saharan dust events (SDE than without SDE.

  10. Short-term forecasting of high resolution local DNI maps with multiple fish-eye cameras in stereoscopic mode

    Science.gov (United States)

    Blanc, Philippe; Massip, Pierre; Kazantzidis, Andreas; Tzoumanikas, Panagiotis; Kuhn, Pascal; Wilbert, Stefan; Schüler, David; Prahl, Christoph

    2017-06-01

    Nowcasting of high resolution maps of direct normal irradiance (DNI) is of interest to efficiently operate Concentrated Solar Power plants. The paper presents a state-of-the-art and innovative methodology, developed in the framework of the FP7 DNICast project, to derive nowcasting of DNI maps from fish-eye cameras in stereoscopic mode. This methodology has been applied at the Plataforma Solar de Almeria: fish-eye cameras at distances from each other between 500 m and 900 m have been used in stereoscopic mode to produce nowcasted 1-min time series of decametric DNI maps.

  11. Memory for pitch in congenital amusia: beyond a fine-grained pitch discrimination problem.

    Science.gov (United States)

    Williamson, Victoria Jane; Stewart, Lauren

    2010-08-01

    Congenital amusia is a disorder that affects the perception and production of music. While amusia has been associated with deficits in pitch discrimination, several reports suggest that memory deficits also play a role. The present study investigated short-term memory span for pitch-based and verbal information in 14 individuals with amusia and matched controls. Analogous adaptive-tracking procedures were used to generate tone and digit spans using stimuli that exceeded psychophysically measured pitch perception thresholds. Individuals with amusia had significantly smaller tone spans, whereas their digits spans were a similar size to those of controls. An automated operation span task was used to determine working memory capacity. Working memory deficits were seen in only a small subgroup of individuals with amusia. These findings support the existence of a pitch-specific component within short-term memory and suggest that congenital amusia is more than a disorder of fine-grained pitch discrimination.

  12. High-Q MgF₂ whispering gallery mode resonators for refractometric sensing in aqueous environment.

    Science.gov (United States)

    Sedlmeir, Florian; Zeltner, Richard; Leuchs, Gerd; Schwefel, Harald G L

    2014-12-15

    We present our experiments on refractometric sensing with ultrahigh-Q, crystalline, birefringent magnesium fluoride (MgF₂) whispering gallery mode resonators. The difference to fused silica which is most commonly used for sensing experiments is the small refractive index of MgF₂ which is very close to that of water. Compared to fused silica this leads to more than 50% longer evanescent fields and a 4.25 times larger sensitivity. Moreover the birefringence amplifies the sensitivity difference between TM and TE type modes which will enhance sensing experiments based on difference frequency measurements. We estimate the performance of our resonators and compare them with fused silica theoretically and present experimental data showing the interferometrically measured evanescent field decay and the sensitivity of mm-sized MgF₂ whispering gallery mode resonators immersed in water. These data show reasonable agreement with the developed theory. Furthermore, we observe stable Q factors in water well above 1 × 10⁸.

  13. Transverse mode instability in high-power ytterbium doped fiber ampliers

    DEFF Research Database (Denmark)

    Hansen, Kristian Rymann

    the otherwise nearly diffraction-limited beam quality of fiber amplifiers, was discovered. The latter effect has impeded the further power scaling of fiber lasers, since the mode instability sets in when the average power exceeds a certain threshold. The purpose of the research presented in this thesis...... based on the beam propagation method, and the second is by a formulation of a coupled-mode model of thermally induced mode instability. The former approach is used to study the effect of quantum defect heating on the guiding properties of the fiber, while the latter provides a simplified description......The last couple of decades have brought an impressive growth in the output power of rare-earth doped fiber lasers and amplifiers, reaching the kW average power regime in both CW and pulsed systems. As a result, even though fiber lasers have excellent heat dissipation properties, thermal effects due...

  14. D33 mode piezoelectric diaphragm based acoustic transducer with high sensitivity

    KAUST Repository

    Shen, Zhiyuan

    2013-01-01

    This paper presents the design, fabrication, and characterization of an acoustic transducer using a piezoelectric freestanding bulk diaphragm as the sensing element. The diaphragm bearing the spiral electrode operates in d 33 mode, which allows the in-plane deformation of the diaphragm to be converted to the out-of-plane deformation and generates an acoustic wave in the same direction. A finite element code is developed to reorient the material polarization distribution according to the poling field calculated. The first four resonance modes have been simulated and verified by impedance and velocity spectra. The sensitivity and the sound pressure level of the transducer were characterized. The realized sensitivity of 126.21 μV/Pa at 1 kHz is nearly twenty times of the sensitivity of a sandwich d31 mode transducer. © 2012 Elsevier B.V.

  15. Design of a tuned mass damper for high quality factor suspension modes in Advanced LIGO.

    Science.gov (United States)

    Robertson, N A; Fritschel, P; Shapiro, B; Torrie, C I; Evans, M

    2017-03-01

    We discuss the requirements, design, and performance of a tuned mass damper which we have developed to damp the highest frequency pendulum modes of the quadruple suspensions which support the test masses in the two advanced detectors of the Laser Interferometric Gravitational-Wave Observatory. The design has to meet the requirements on mass, size, and level of damping to avoid unduly compromising the suspension thermal noise performance and to allow retrofitting of the dampers to the suspensions with minimal changes to the existing suspensions. We have produced a design satisfying our requirements which can reduce the quality factor of these modes from ∼500 000 to less than 10 000, reducing the time taken for the modes to damp down from several hours to a few minutes or less.

  16. Single-band high absorption and coupling between localized surface plasmons modes in a metamaterials absorber

    Science.gov (United States)

    Zhong, Min; Liu, Shui Jie; Xu, Bang Li; Wang, Jie; Huang, Hua Qing

    2017-10-01

    In this paper, we design and simulate a metamaterials absorbers based on the resonance of the local surface plasmon (LSP) mode. The damping constant of gold layer is optimized in simulations to eliminate the effect of the inappropriate material parameters on the electromagnetic properties of the proposed metamaterial absorber. The horizontal distance between two metal particles is optimized in simulations and a perfect absorption resonance peak is achieved due to the strong coupling of LSP modes. A new absorption peak is obtained when the horizontal distance is 0 nm. The vertical distance between the new metal particles and the bottom metal layer is reduced, which leads to the absorption peak reduce based on the reduction of the intensity of LSP modes. A new absorption peak is obtained when the new metallic particle and the bottom gold layer form a whole structure.

  17. Study of the enhancement-mode AlGaN/GaN high electron mobility transistor with split floating gates

    Science.gov (United States)

    Wang, Hui; Wang, Ning; Jiang, Ling-Li; Zhao, Hai-Yue; Lin, Xin-Peng; Yu, Hong-Yu

    2017-11-01

    In this work, the charge storage based split floating gates (FGs) enhancement mode (E-mode) AlGaN/GaN high electron mobility transistors (HEMTs) are studied. The simulation results reveal that under certain density of two dimensional electron gas, the variation tendency of the threshold voltage (Vth) with the variation of the blocking dielectric thickness depends on the FG charge density. It is found that when the length sum and isolating spacing sum of the FGs both remain unchanged, the Vth shall decrease with the increasing FGs number but maintaining the device as E-mode. It is also reported that for the FGs HEMT, the failure of a FG will lead to the decrease of Vth as well as the increase of drain current, and the failure probability can be improved significantly with the increase of FGs number.

  18. High-power terahertz optical pulse generation with a dual-wavelength harmonically mode-locked Yb:YAG laser

    Science.gov (United States)

    Zhuang, W. Z.; Chang, M. T.; Su, K. W.; Huang, K. F.; Chen, Y. F.

    2013-07-01

    We report on high-power terahertz optical pulse generation with a dual-wavelength harmonically mode-locked Yb:YAG laser. A semiconductor saturable absorber mirror is developed to achieve synchronously mode-locked operation at two spectral bands centered at 1031.67 and 1049.42 nm with a pulse duration of 1.54 ps and a pulse repetition rate of 80.3 GHz. With a diamond heat spreader to improve the heat removal efficiency, the average output power can be up to 1.1 W at an absorbed pump power of 5.18 W. The autocorrelation traces reveal that the mode-locked pulse is modulated with a beat frequency of 4.92 THz and displays a modulation depth to be greater than 80%.

  19. Demonstration of a High-Order Mode Input Coupler for a 220-GHz Confocal Gyrotron Traveling Wave Tube

    Science.gov (United States)

    Guan, Xiaotong; Fu, Wenjie; Yan, Yang

    2018-02-01

    A design of high-order mode input coupler for 220-GHz confocal gyrotron travelling wave tube is proposed, simulated, and demonstrated by experimental tests. This input coupler is designed to excite confocal TE 06 mode from rectangle waveguide TE 10 mode over a broadband frequency range. Simulation results predict that the optimized conversion loss is about 2.72 dB with a mode purity excess of 99%. Considering of the gyrotron interaction theory, an effective bandwidth of 5 GHz is obtained, in which the beam-wave coupling efficiency is higher than half of maximum. The field pattern under low power demonstrates that TE 06 mode is successfully excited in confocal waveguide at 220 GHz. Cold test results from the vector network analyzer perform good agreements with simulation results. Both simulation and experimental results illustrate that the reflection at input port S11 is sensitive to the perpendicular separation of two mirrors. It provides an engineering possibility for estimating the assembly precision.

  20. Study of high frequency MHD modes from ECE radiometer in Tore Supra

    Directory of Open Access Journals (Sweden)

    Dubuit N.

    2012-09-01

    Full Text Available Tore Supra ECE diagnostic has been recently upgraded to study MHD modes driven by energetic particles up to 400 kHz. To improve the measurement sensitivity, the ECE signals of the 32 channels radiometer were amplified just below the saturation limit and sources of noise were investigated in order to keep it as low as possible. With such an improvement, fast