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Sample records for doppler image-derived tei

  1. Evaluating the cardiac function of duchenne muscular dystrophy with Doppler Tei index

    International Nuclear Information System (INIS)

    Objective: To evaluate the cardiac function of early Duchenne muscular dystrophy (DMD) by left ventricular ejection fraction (LVEF) and pulse Doppler Tei index. Methods: Twenty-eight DMD patients and fifteen normal people were studied. LVEF, E/A and Tei index were measured and calculated by M-mode and Pulse wave Doppler respectively. Results: Compared with control group, Tei index and IRT were significantly high, and there were not significant difference in LVEF(%) and E/A. Conclusion: Tei index was valuable in assessing cardiac function of early DMD. (authors)

  2. Índice de Tei, nuevo indicador doppler para el estudio de la insuficiencia cardíaca Tei's index, a new doppler indicator for the study of heart failure

    Directory of Open Access Journals (Sweden)

    Javier González Fernández

    2004-08-01

    Full Text Available La mayoría de los pacientes con insuficiencia cardíaca (IC presentan afectación sistólica y diastólica combinadas; un índice derivado del doppler, conocido cono índice de Tei, permite evaluar de forma no invasiva ambas alteraciones. Se estudiaron 25 pacientes con edad promedio de 55 ± 16 años con IC. Se compararon los datos obtenidos con los de un grupo de personas sanas. Se observó un incremento de IT en los pacientes con IC. Se halló una relación estadísticamente significativa entre el IT y la fracción de eyección ventricular izquierda y el tiempo de desaceleración del pico E en el flujograma mitral de doppler. Se presentaron los resultados del seguimiento de los pacientes en un período de 3 y 6 meses. Se concluyó que aquellos que presentan el índice de Tei elevado tienen una evolución desfavorable a los 6 meses.Most of the patients with heart failure present combined systolic and diastolic affectation, an index derived from doppler known as Tei's index that allow to evaluate both alterations in a non-invasive way. 25 patients aged 55 ± 16 as an average that suffered from heart failure were studied. The obtained data were compared with those of a sound group. It was observed an increase of Tei's index among patients with heart failure. It was found a statistically significant relation between the Tei's index, the left ventricular ejection fraction and the deacceleration time of peak E in the doppler's mitral flow chart. The results of the follow-up of patients in a period from 3 to 6 months were shown. It was concluded that those with an elevated Tei's index have an unfavorable evolution at 6 months.

  3. Tissue Doppler Tei index estimation of global function of right ventricle in patients with hypertension

    International Nuclear Information System (INIS)

    Objective: An evaluation of tissue Doppler Tei index in estimating global function of right ventricle in patients with hypertension. Methods: Twenty patients with hypertension and 20 health individuals as the control group were enrolled in the study. The tricuspid annular motion was obtained by pulse-wave Doppler tissue imaging (PW-DTI). The peak systolic velocity (Sm) and its integral of velocity and time (Sm-VTI), as well as the peak velocity at early diastole(et) and at late diastole (at) were measured respectively. ICT, ET and IRT of right ventricle were taken with ECG(L II). Tel index was calculated. Results: 1 The Tei index of RV in hypertension group was significantly higher than that of the control group(0.63 ± 0.14 VS 0.50 ± 0.07. Pt and et/at of the study group were significantly lower than that of the contral group. (Sm: 12.44±3.43 vs 14.66±2.38 cm/s; Pt/at: 11.37±3.58 vs 17.97±3.95 cm/s; Pt/at: 0.83±0.23 vs 1.44±0.48; Pt and et/at(Sm-VTI, r= -0.368, P t, r=-0.507, Pt/at, r= -0.425, P<0.01). Conclusion: The Tei index of RV obtained by PW-TDI was an easy method with high sensitivity, which may be applied to assess the global function of RV in patients with hypertension. (authors)

  4. Tissue Doppler Imaging-derived Diastolic Function Assessment in Children With Sickle Cell Disease and Its Relation With Ferritin.

    Science.gov (United States)

    Olson, Michelle; Hebson, Camden; Ehrlich, Alexandra; New, Tamara; Sachdeva, Ritu

    2016-01-01

    Diastolic dysfunction has been shown to occur earlier than systolic dysfunction in iron overload states in adult patients with sickle cell disease (SCD). Tissue Doppler imaging (TDI)-derived E/E' has emerged as a noninvasive marker of diastolic function. We sought to determine diastolic function in children with SCD and study its relation with iron overload. A retrospective review of medical records of 225 pediatric patients with SCD who received an echocardiogram between January 2008 and December 2012 was performed. Echocardiographic measures including M-mode, spectral Doppler, and TDI-derived E/E' were compared with previously published data in healthy children. The left ventricular end-diastolic and end-systolic dimensions were significantly higher in SCD (P8, indicating elevated left ventricular filling pressure. However, there was no significant correlation between ferritin level and E/E' ratios. Pediatric patients with SCD have a high prevalence of elevated estimated left ventricular filling pressure, but this does not correlate with ferritin levels. PMID:26491854

  5. Questions & Answers for TEI Newcomers

    OpenAIRE

    Romary, Laurent

    2009-01-01

    This paper provides an introduction to the Text Encoding Initia-tive (TEI), focused at bringing in newcomers who have to deal with a digital document project and are looking at the capacity that the TEI environment may have to fulfil his needs. To this end, we avoid a strictly technical presentation of the TEI and concentrate on the actual issues that such projects face, with parallel made on the situation within two institutions. While a quick walkthrough the TEI technical ...

  6. Questions & Answers for TEI Newcomers

    OpenAIRE

    Romary, Laurent

    2008-01-01

    This paper provides an introduction to the Text Encoding Initia-tive (TEI), focused at bringing in newcomers who have to deal with a digital document project and are looking at the capacity that the TEI environment may have to fulfil his needs. To this end, we avoid a strictly technical presentation of the TEI and concentrate on the actual issues that such projects face, with parallel made on the situation within two institutions. While a quick walkthrough the TEI technical framework is provi...

  7. Intraoperative transesophageal echocardiographic assessment of left ventricular Tei index in congenital heart disease

    Directory of Open Access Journals (Sweden)

    Shanthi Sivanandam

    2015-01-01

    Full Text Available Background: Use of the Tei index has not been described to assess myocardial function before or after surgery in pediatric patients. This study was designed to evaluate the left ventricular (LV function using the Tei index pre- and post-cardiopulmonary bypass in patients with lesion that result in a volume loaded right ventricle (RV. Methods: Retrospective data on 55 patients who underwent repair of a cardiac defect were analyzed. Patients with volume overload RV (n = 15 were compared to patients without volume overload but with other cardiac defects (n = 40. We reviewed pre- and post-operative LV myocardial performance index (Tei index. Tei index was obtained from transesophageal Doppler echocardiogram. Results: Patients with right heart volume overload, the mean preoperative Tei index was 0.6, with a postoperative mean decrease of 0.207 (P = 0.014. Patients without right heart volume overload, the mean preoperative Tei was 0.48 with no significant postoperative change (P = 0.82. Conclusion: Pre- and post-operative transesophageal echocardiogram assessment provides an easy and quick way of evaluating LV function intra-operatively using LV Tei index. Preoperative LV Tei index was greater in the RV volume overload defects indicating diminished LV global function. This normalized in the immediate postoperative period, implying an immediate improvement in LV function. In patients without right heart volume load, consist of other cardiac defects, demonstrated no changes in the pre- and post-operative LV Tei. This implies that LV function was similar after the surgery.

  8. Encoding the Discipline: English Graduate Student Reflections on Working with TEI

    OpenAIRE

    Ives, Maura; Hierro, Victor Del; Kelsey, Bailey; Smith, Laura Catherine; Sumners, Christina

    2014-01-01

    Students in two graduate English seminars at Texas A&M were offered an introduction to TEI encoding and were surveyed as to their experiences. Four students presented short papers to the TEI meeting that incorporated both the survey responses and their own perspectives as relative newcomers to TEI. These papers demonstrate why it is important to incorporate TEI in the graduate curriculum, how that incorporation might best be approached, and what happens when TEI is viewed through a disciplina...

  9. Polytypism in the Nb3TeI7 system

    International Nuclear Information System (INIS)

    h-Nb3TeI7 represents the first polytype to be observed in a single ternary system of the layered Nb3QX7 family (Q=S, Se, Te; X=Cl, Br, I). This compound was synthesized by stoichiometric reaction of the elements at temperatures from 600 to 800 C, and was characterized by single crystal and powder X-ray diffraction. h-Nb3TeI7 crystallizes in the Nb3SBr7 structure type: space group P3m1, a=7.642(1) A, c=6.897(1) A and V=348.82(8) A3. h-Nb3TeI7 differs from the previously reported polytype, hc-Nb3TeI7, by having a simpler anion layer stacking sequence involving fewer 2?[Nb3TeI7] layers per unit cell. Complete structural determinations of the new compound h-Nb3TeI7 as well as of the previously reported hc-Nb3TeI7 are included. (orig.)

  10. Using TEI, CMDI and ISOcat in CLARIN-DK

    DEFF Research Database (Denmark)

    Hansen, Dorte Haltrup; Offersgaard, Lene; Olsen, Sussi

    2014-01-01

    This paper presents the challenges and issues encountered in the conversion of TEI header metadata into the CMDI format. The work is carried out in the Danish research infrastructure, CLARIN-DK, in order to enable the exchange of language resources nationally as well as internationally, in particular with other partners of CLARIN ERIC. The paper describes the task of converting an existing TEI specification applied to all the text resources deposited in DK-CLARIN. During the task we have tried t...

  11. Position Estimation Using Image Derivative

    Science.gov (United States)

    Mortari, Daniele; deDilectis, Francesco; Zanetti, Renato

    2015-01-01

    This paper describes an image processing algorithm to process Moon and/or Earth images. The theory presented is based on the fact that Moon hard edge points are characterized by the highest values of the image derivative. Outliers are eliminated by two sequential filters. Moon center and radius are then estimated by nonlinear least-squares using circular sigmoid functions. The proposed image processing has been applied and validated using real and synthetic Moon images.

  12. Welcome to the TEI’10 Proceedings

    DEFF Research Database (Denmark)

    Pederson, Thomas; Shaer, Orit

    2010-01-01

    We welcome you to the proceedings of the 4th ACM International Conference on Tangible, Embedded, and Embodied Interaction -- TEI'10, held in Cambridge, Massachusetts, on the 25th -27th of January 2010. TEI'10 continues the pursuit of key areas of innovation in respect to tangible, embedded, and embodied interactions. These concerns include the interlinking of digital and physical worlds through tangible and embodied interaction and the computational augmentation of everyday objects and environments in new ways through embedded technologies. Research and practice in these innovative areas lead to works of tangible interfaces, graspable interfaces, physical computing, whole-body interaction, gesture-based interfaces, and interactive surfaces. Designing such systems requires interdisciplinary thinking as their creation not only encompasses software, electronics, and mechanics, but also form, aesthetics, and social impact. The high quality, original, and diverse works in these proceedings is a testament to thegrowth and importance of the field of tangible computing. The call for papers attracted 160 submissions from approximately 20 countries spanning Africa, Asia, Canada, Europe, and the United States. All submissions were peer and blind reviewed and received at least three independent expert reviews. In total, 54 papers were accepted for an acceptance rate of 34%. The papers are a mix of 2, 4, 8 pages in length. From these contributions, the program at the conference includes 16 long talks, 8 short talks, 1 short talk and a demo, 22 demos, and 7 posters. We are proud to continue the tradition of a plenary session for all talks, demos and posters. The paper sessions are organized along five themes. Bridging the Physical and Digital Worlds is at the center of tangible computing investigations that explore the intersections of computation and physicality. Toolkits and Enabling Technologies explores the functionality of applications and technologies for users and the tools for designers and developers. Physical Interactions, Perspectives, and Design Techniques represent the emerging and refined thinking in the field that investigates embodiment, reflections and frameworks, and emerging techniques. Materials, Garments and Lights uncovers the serious investigations into new materials and expressions for tangible computing. Lastly, Learning through Physical Interaction contributes to the invaluable intersections between tangible computing and learning. In addition, the demonstrations and posters session gives concrete and vibrant evidence for the serious and diverse research in the field. We are also proud to include innovations in the conference program this year. A new track was created known as Explorations aimed at attracting thought provoking, evocative, visually and sensually rich work by a diverse group of creators. 46 submissions were received from which an expert jury accepted 10 contributions. These contributions are interwoven into the papers and demonstration tracks at the conference. Another new track is Studios, a series of 21 workshop sessions open to all conference participants that offer novel hands-on experiences ranging from the exploration of new development toolkits, to prototype design techniques, and the use of emerging or traditional materials in creatively applied way. Lastly, the Graduate Student Consortium reflects the essential need for the participation and development of new scholars in the areas of tangible computing. 38 submissions were received and 13 contributions were accepted after blind reviews by at least three independent and expert reviewers per submission.

  13. A TEI P5 Manuscript Description Adaptation for Cataloguing Digitized Arabic Manuscripts

    OpenAIRE

    Soualah, Mohammed Ourabah; Hassoun, Mohamed

    2014-01-01

    It is incumbent upon libraries holding Arabic manuscripts to provide access to digitized surrogates of their holdings. Users require access both by authority list and by content. Thus, an exhaustive cataloguing method is essential. The TEI P5 Manuscript Description module is a suitable tool for manuscript cataloguing, but it lacks certain features that would allow for exhaustive description of ancient Arabic manuscripts. In this article we make several suggestions that would augment the TEI P...

  14. The usefulness of the TEI surgery in Thessaloniki

    Directory of Open Access Journals (Sweden)

    Kourkouta L.

    2010-04-01

    Full Text Available It is a known fact that in every higher academic institution functions a surgery that aims at providing care or first aid to workers and students. Aim: The aim of the present study is to show the usefulness of surgery of TEI in Thessaloniki during its daily operation and the offer of valuable care and help not only to employees but to the students as well. Material - method: It is a retrospective-comparative research. The files of surgery of TEI in Thessaloniki were studied during 2005-2007. The descriptive statistics was used on the equitable study, recording, processing and analysis of these elements via the Excel program. Results-Discussion: By the retrospective-comparative study of pre-mentioned elements are pointed out following that at a three-year period 2005-2007 2391 individuals visited the surgery with the employees being 1052 (44% out of which 624 (59% were women and 428 (41% were men The students were 1399 (56% out of which 547 (41% were boys and 792 (59% were girls In the whole sample 975 (40,75% were men (students and employees and1416 (59,23% were women (students and employees. Regarding the reasons for which men and women visited the surgery headache (33%, hypertension (19%, control of arterial pressure (25%, dysmenorrhea (10%, gastralgia (6%, toothache (2%, lumbago (2%, dizziness (2% and measurement of blood glucose (1%. As regards the two sexes (men and women, it seems that women except for the dysmenorrhea visit mostly the surgery because of headaches, gastralgia, toothache, lumbago and dizziness. On the contrary, men usually visit the surgery because of hypertension, control of arterial pressure and measurement of blood glucose Conclusions: According to the information above, the usefulness of surgery is proved, which covers the real needs of health service and care for both employees and students.

  15. Right Ventricular Tissue Doppler in Space Flight

    Science.gov (United States)

    Hamilton, Douglas R.; Barratt, Michael R.; Sargsyan, Ashot E.; Ebert, Douglas; Garcia, Kathleen M.; Martin, David S.; Dulchavsky, Scott A.; Duncan, J. Michael

    2009-01-01

    Tissue Doppler (TD) registers movement of a given sample of cardiac tissue throughout the cardiac cycle. TD spectra of the right ventricle (RV) were obtained from a long-duration ISS crewmember as a portion of an ongoing experiment ("Braslet" test objective). To our knowledge, this is the first report of RV TD conducted in space flight, and the data represent reproducibility and fidelity of this application in space and serve as the first "space normal" data set. Methods RV TD was performed by astronaut scientists remotely guided by an ultrasound expert from Mission Control Center, Houston, TX. In four of the subjects, RV TD was acquired from the free wall near the tricuspid annulus in two separate sessions 4 to 7 days apart. A fifth subject had only one session. All digital DICOM frames were exported for off-line analysis. Systolic (S ), early diastolic (E ) and late diastolic (A ) velocities were measured. RV Tei-index was calculated using diastolic and systolic time intervals as a combined measure of myocardial performance. Results and Discussion The mean values from the first 4 subjects (8 sessions) were used as the on-orbit reference data, and subject 5 was considered as a hypothetical patient for comparison (see Table). The greatest difference was in the early diastolic A (31 %) yet the standard deviation (a) for A amongst the reference subjects was 2.25 (mean = 16.02). Of interest is the Tei index, a simple and feasible indicator of overall ventricular function; it was similar amongst all the subjects. The late diastolic A seems to compensate for the variance in E . Normal Tei index for the RV is < 0.3, yet our data show all but one subject consistently above this level, notwithstanding their nominal responses to daily exercise in microgravity. These data remind us that the physiology of RV preload in altered gravity environments is still not completely understood.

  16. Pre-operative Tei Index does not predict left ventricular function immediately after mitral valve repair

    Directory of Open Access Journals (Sweden)

    Chirojit Mukherjee

    2012-01-01

    Full Text Available Echocardiographic assessment of systolic left ventricular (LV function in patients with severe mitral regurgitation (MR undergoing mitral valve (MV repair can be challenging because the measurement of ejection fraction (EF or fractional area change (FAC in pathological states is of questionable value. The aim of our study was to evaluate the usefulness of the pre-operative Tei Index in predicting left ventricular EF or FAC immediately after MV repair. One hundred and thirty patients undergoing MV repair with sinus rhythm pre- and post-operatively were enrolled in this prospective study. Twenty-six patients were excluded due to absence of sinus rhythm post-operatively. Standard transesophageal examination(IE 33,Philips,Netherlands was performed before and after cardiopulmonary bypass according to the guidelines of the ASE/SCA. FAC was determined in the transgastric midpapillary short-axis view. LV EF was measured in the midesophageal four- and two-chamber view. For calculation of the Tei Index, the deep transgastric and the midesophageal four-chamber view were used. Statistical analysis was performed with SPSS 17.0. values are expressed as mean with standard deviation. LV FAC and EF decreased significantly after MV repair (FAC: 56±12% vs. 50±14%, P<0.001; EF: 58±11 vs. 50±12Έ P<0.001. The Tei Index decreased from 0.66±0.23 before MV repair to 0.41±0.19 afterwards (P<0.001. No relationship between pre-operative Tei Index and post-operative FAC or post-operative EF were found (FAC: r=−0.061, P=0.554; EF: r=−0.29, P=0.771. Conclusion: Pre-operative Tei Index is not a good predictor for post-operative FAC and EF in patients undergoing MV repair.

  17. Crystal structure of human cyclin-dependent kinase-2 complex with MK2 inhibitor TEI-I01800: insight into the selectivity

    Energy Technology Data Exchange (ETDEWEB)

    Fujino, Aiko; Fukushima, Kei; Kubota, Takaharu; Kosugi, Tomomi; Takimoto-Kamimura, Midori, E-mail: m.kamimura@teijin.co.jp [Teijin Pharma Limited, 4-3-2 Asahigaoka, Hino-shi, Tokyo 191-8512 (Japan)

    2013-11-01

    The Gly-rich loop of cyclin-dependent kinase 2 (CDK2) bound to TEI-I01800 as an MK2 specific inhibitor forms a ?-sheet which is a common structure in CDK2–ligand complexes. Here, the reason why TEI-I01800 does not become a strong inhibitor against CDK2 based on the conformation of TEI-I01800 is presented. Mitogen-activated protein kinase-activated protein kinase 2 (MK2 or MAPKAP-K2) is a Ser/Thr kinase from the p38 mitogen-activated protein kinase signalling pathway and plays an important role in inflammatory diseases. The crystal structure of the MK2–TEI-I01800 complex has been reported; its Gly-rich loop was found to form an ?-helix, not a ?-sheet as has been observed for other Ser/Thr kinases. TEI-I01800 is 177-fold selective against MK2 compared with CDK2; in order to understand the inhibitory mechanism of TEI-I01800, the cyclin-dependent kinase 2 (CDK2) complex structure with TEI-I01800 was determined at 2.0 Å resolution. Interestingly, the Gly-rich loop of CDK2 formed a ?-sheet that was different from that of MK2. In MK2, TEI-I01800 changed the secondary structure of the Gly-rich loop from a ?-sheet to an ?-helix by collision between Leu70 and a p-ethoxyphenyl group at the 7-position and bound to MK2. However, for CDK2, TEI-I01800 bound to CDK2 without this structural change and lost the interaction with the substituent at the 7-position. In summary, the results of this study suggest that the reason for the selectivity of TEI-I01800 is the favourable conformation of TEI-I01800 itself, making it suitable for binding to the ?-form MK2.

  18. Process' standardization and change management in higher education. The case of TEI of Athens

    Science.gov (United States)

    Chalaris, Ioannis; Chalaris, Manolis; Gritzalis, Stefanos; Belsis, Petros

    2015-02-01

    The establishment of mature operational procedures and the effort of standardizing and certifying these procedures is a particularly arduous and demanding task which requires strong commitment from management to the existing objectives, administrative stability and continuity, availability of resources, an adequate implementation team with support from all stakeholders and of course great tolerance until tangible results of the investment are shown. Ensuring these conditions, particularly in times of economic crisis, is an extremely difficult task for large organizations such as TEI of Athens where there is heterogeneity in personnel and changes in the administrative hierarchy arise plethora of additional difficulties and require an effective change management. In this work we depict the path of standardization and certification of administrative functions of TEI of Athens, with emphasis on difficulties encountered and how to address them and in particular issues of change management and the culture related to this effort. The requirement for infrastructure needed to be maintained in processes and tools process & strategic management is embodied, in order to evolve mechanisms for continuous improvement processes and storage / recovery of the resulting knowledge. The work concludes with a general design of a road map of internal audit and continuous improvement processes for a large institution of higher education.

  19. Doppler flowmeter

    Science.gov (United States)

    Karplus, Henry H. B. (Hinsdale, IL); Raptis, Apostolos C. (Downers Grove, IL)

    1983-01-01

    A Doppler flowmeter impulses an ultrasonic fixed-frequency signal obliquely into a slurry flowing in a pipe and a reflected signal is detected after having been scattered off of the slurry particles, whereby the shift in frequencies between the signals is proportional to the slurry velocity and hence slurry flow rate. This flowmeter filters the Doppler frequency-shift signal, compares the filtered and unfiltered shift signals in a divider to obtain a ratio, and then further compares this ratio against a preset fractional ratio. The flowmeter utilizes a voltage-to-frequency convertor to generate a pulsed signal having a determinable rate of repetition precisely proportional to the divergence of the ratios. The pulsed signal serves as the input control for a frequency-controlled low-pass filter, which provides thereby that the cutoff frequency of the filtered signal is known. The flowmeter provides a feedback control by minimizing the divergence. With the cutoff frequency and preset fractional ratio known, the slurry velocity and hence flow will also be determinable.

  20. The Training Evaluation Inventory (TEI)--Evaluation of Training Design and Measurement of Training Outcomes for Predicting Training Success

    Science.gov (United States)

    Ritzmann, Sandrina; Hagemann, Vera; Kluge, Annette

    2014-01-01

    Training evaluation in research and organisational contexts is vital to ensure informed decisions regarding the value of training. The present study describes the development of a valid and reliable training evaluation inventory (TEI), as it does not exist so far. The objectives were a) to construct an instrument that is theoretically and…

  1. The Training Evaluation Inventory (TEI)--Evaluation of Training Design and Measurement of Training Outcomes for Predicting Training Success

    Science.gov (United States)

    Ritzmann, Sandrina; Hagemann, Vera; Kluge, Annette

    2014-01-01

    Training evaluation in research and organisational contexts is vital to ensure informed decisions regarding the value of training. The present study describes the development of a valid and reliable training evaluation inventory (TEI), as it does not exist so far. The objectives were a) to construct an instrument that is theoretically and…

  2. Left Ventricular Diastolic and Systolic Performance: A Study Using Tei Index in Adulthood Patients with Thalassemia Major

    Directory of Open Access Journals (Sweden)

    Kaveh Mousavi Kani

    2011-04-01

    Full Text Available Introduction: Cardiac complications, including heart failure, are the most important secondary ones of the thalassemia major disease, which manifests itself in adolescence and early adulthood. Appropriate, low cost diagnostic tools available as well as knowing its related factors are the most important components of therapy in these patients, given the importance of these complications, or by examining and revealing early symptoms. Thus, in this study, we intend to examine the systolic and diastolic ventricular effects in adult patients with the help of Tei index. Methods: 70 adult patients with thalassemia major were examined in this study. Frequency of Tei index and its association with factors such as age, sex, level of packed cell injection, as well as hemosiderosis were measured in two blood levels of more than 1000 ferretins. Results: In this study, 70 youth adult patients with thalassemia major with an average age of 21.3± 2.8 years were studied, 31 were male (44.4%. Tei index were abnormal in 16 patients (24%. There is no statistically significant correlation between the Tei index and one of the variables of age, gender, number and duration of blood transfusion and deferoxamine, the hemoglobin level and the number of ferretins (P>0.05. Discussion: Study on Tei index shows that many patients are subclinically involved in the disease before the onset of clinical symptoms of heart failure, the subject which raises the need for early diagnosis of the disease; and it seems that none of the demographic factors or factors related to disease cannot be considered as a main cause or warning of the disease; and the above results can be confirmed only on the basis of paraclinical tests.

  3. Assesment of the TEI index of myocardial performance in dogs with doxorubicin-induced cardiomiopathy / Evaluación del índice de desempeño miocárdico de TEI en perros con cardiomiopatía inducida por doxorrubicina

    Scientific Electronic Library Online (English)

    MG, Sousa; D, Paulino-Junior; JPE, Pascon; GB, Pereira-Neto; R, Carareto; AA, Camacho.

    Full Text Available El desarrollo de una cardiomiopatía dosis dependiente es la principal limitación para el uso de doxorrubicina en protocolos de quimioterapia tanto en seres humanos como en animales. En estos casos, la función global del miocardio puede ser cedida, teniendo como resultado signos atribuibles a la insu [...] ficiencia cardíaca congestiva. En este estudio, nosotros investigamos la capacidad del índice de desempeño miocárdico de Tei para identificar disfunción de miocardio en perros sanos tratados con doxorrubicina a una dosis cumulativa de 210 mg/m² en un periodo de 147 días, comparándolo con otros indicadores ecográficos estándar de función sistólica y diastólica. Nuestros resultados indicaron que el índice de Tei, el tiempo de relajación isovolumétrica, el período de pre-eyección, y la relación período de pre-eyección/tiempo de eyección ventricular izquierda pudieron identificar los efectos cardiotóxicos de doxorrubicina en la función cardíaca cuando sólo 60 mg/m² habían sido administrados, mientras los parámetros estándar sistólicos y diastólicos, incluso el diámetro sistólico del ventrículo izquierdo, la fracción de eyección y la fracción de acortamiento, necesitaron por lo menos 120 mg/mg² para empeorar. Se concluye que la terapia prolongada con antraciclinas perjudica las funciones sistólica y diastólica, que pueden ser documentadas antes adicionándose el índice de Tei a la evaluación ecográfica estándar en animales que reciben doxorrubicina. Abstract in english The development of a dose-dependent cardiomyopathy is the main limitation for the use of doxorubicin in chemotherapy protocols in both humans and animals. In this setting, the global myocardial function may be compromised resulting in signs of congestive heart failure. In this study, we investigated [...] the ability of the Tei index of myocardial performance to identify myocardial dysfunction in healthy dogs receiving doxorubicin to a cumulative dose of 210 mg/m² over 147 days, comparing it with other standard echocardiographic indicators of systolic and diastolic function. Our results indicated that the Tei index, the isovolumic relaxation time, pre-ejection period and the pre-ejection period-to-left ventricular ejection time ratio were able to identify the cardiotoxic effects of doxorubicin on cardiac function when only 60 mg/m² had been administered, while the standard systolic and diastolic parameters, including left ventricular diameter at systole, ejection fraction, and fractional shortening needed at least 120 mg/mg² to deteriorate. We concluded that prolonged anthracycline therapy compromises both systolic and diastolic functions, which may be documented earlier by including the Tei index evaluation to the standard echocardiographic assessment of animals receiving doxorubicin.

  4. TEI Piraeus students' knowledge on the beneficial applications of nuclear physics: Nuclear energy, radioactivity - consequences

    CERN Document Server

    Pilakouta, Mirofora

    2011-01-01

    The recent nuclear accident in Japan revealed the confusion and the inadequate knowledge of the citizens about the issues of nuclear energy, nuclear applications, radioactivity and their consequences In this work we present the first results of an ongoing study which aims to evaluate the knowledge and the views of Greek undergraduate students on the above issues. A web based survey was conducted and 131 students from TEI Piraeus answered a multiple choice questionnaire with questions of general interest on nuclear energy, nuclear applications, radioactivity and their consequences. The survey showed that students, like the general population, have a series of faulty views on general interest nuclear issues. Furthermore, the first results indicate that our educational system is not so effective as source of information on these issues in comparison to the media and internet

  5. The Petrology of the Wong Tei Tung Stone Tool Manufacturing Site, Sham Chung, Hong Kong Sar, China

    Directory of Open Access Journals (Sweden)

    Vin Davis

    2009-09-01

    Full Text Available The Wong Tei Tung archaeological site was discovered in 2003. Two periods have been proposed: an earlier period dating to around 40,000 years bp, and a later period dating to around 7000 years bp, but these dates should be treated cautiously. Initially, reported research found a few traits of the Wong Tei Tung assemblage to be similar to South-east Asia lithics, especially the short axe and Sumatralith cores. It has been reported that the Wong Tei Tung assemblage is a lithic cluster of certain 'techno-complex' implements rather than an archaeological culture; it offers a glimpse of lithic manufacturing in adaptation to its particular coastal environment. The published evidence points to a production of stone tools that considerably exceeded anticipated immediate local need. It is likely, therefore, that products from the site were distributed widely across the Zhujiang Estuary (Pearl River area and beyond (Fig. 1: map. This article presents the results of initial investigations into the geological setting of the site; provides new petrographic descriptions using data obtained from thin sections and geochemical analyses; and makes tentative comparisons with similar archaeological stone tool manufacturing sites in Britain.

  6. Myocardial function in Saudi adolescents with vitamin D deficiency: Tissue Doppler imaging study.

    Science.gov (United States)

    Matter, Mohamed; El-Sherbiny, Enas; Elmougy, Atef; Abass, Mohamed; Aldossary, Sahar; Ali, Waleed Abu

    2016-01-01

    Vitamin D deficiency is a common health problem in Saudi Arabia especially in children and adolescents. Many studies have reported the relation between low 25-Hydroxyvitamin D (25(OH)D) levels with cardiovascular diseases risk factors as well as cardiovascular events, including stroke, myocardial infarction, and congestive heart failure. This study was conducted to evaluate the effect of 25(OH)D deficiency on the myocardial function and other echocardiographic variables in adolescent, using tissue Doppler imaging (TDI) and to correlate these parameters with 25(OH)D level. The study included 84 healthy adolescents, consecutively selected from adolescents attending the outpatient clinic of Saad Specialist Hospital, KSA between September 2013 and October 2014. The study population was classified into two groups; vitamin D deficient group with 25(OH)D level less than 20 ng/mL and normal vitamin D (control group) with 25(OH)D equal or more than 30 ng/mL. Both groups were subjected to measuring hemoglobin level, serum albumin, creatinine, total calcium, Phosphorous, intact parathyroid hormone (iPTH), B-type natriuretic peptide (BNP), and 25(OH)D levels. Both conventional and pulsed wave TDI were done for all participants. TDI measurements showed significant higher LV Tei Index and RV Tei index when compared to the control group (0.61 ± 0.11 Vs 0.32 ± 0.05 p < 0.0001), (0.54 ± 0.14 Vs 0.40 ± 0.06 p < 0.0001) respectively. Mitral and tricuspid annular systolic velocities were significantly lower in vitamin D deficient group (6.99 ± 1.92 Vs 10.69 ± 0.31 cm/sec p < 0.0001 and 12.30 ± 2.14 Vs 13.89 ± 0.29 p < 0.0001 respectively). The mitral and tricuspid E/Em ratio was significantly higher in vitamin D deficient group than control group (p < 0.0001, p 0.005) respectively. Left ventricular internal diameter at end-diastole (LVIDd) was significantly higher in vitamin D deficient group (44.72 ± 6.33 Vs 40.36 ± 6.21 p 0.003). Serum 25(OH)D level showed significant negative correlation with LV Tei index (r = -0.668, p < 0.0001), RV Tei index (r = -0.421, p < 0.0001). Vitamin D deficiency is associated with subtle systolic and diastolic myocardial dysfunction in Saudi adolescents. TDI is a useful tool for detecting early changes in the myocardium in this particular group. PMID:26778902

  7. Radon and remediation measures near B?i?a-?tei old uranium mine (Romania)

    Science.gov (United States)

    Cosma, Constantin; Cuco?, Alexandra; Papp, Botond; Begy, Robert; Dicu, Tiberiu; Moldovan, Mircea; Tru??, Lucia; Ni??, Dan; Burghele, Bety-Denissa; Suciu, Liviu; Sainz, Carlos

    2013-08-01

    B?i?a-?tei mine is an open pit mine in NW Romania (West Carpathian Mountains). It was the largest surface uranium deposit in the world. Two means of uranium transport and dissemination were used over time. The first was the natural way, represented by transportation of geological sediments by Cri?ul-B?i?a River that crosses the B?i?a surface deposit. These sediments were used as building materials (stone, gravel, sand). The second way was related to the people living in this valley, who used also the uranium waste as building material. The preliminary indoor radon concentrations measured in the buildings ranged from 40 to 4000 Bq m-3 with a mean value of 241 Bq m-3. A focused radon survey facilitated the selection of 20 houses with the highest indoor radon that were therefore proposed for remediation. To find the radon sources of these houses, systematic investigations on radon were performed. The remedial measures for these 20 houses were tested on a chosen pilot house.

  8. Christian Doppler and the Doppler effect

    Science.gov (United States)

    Toman, Kurt

    1984-04-01

    A summary is given of Doppler's life and career. He was born 180 years ago on November 29, 1803, in Salzburg, Austria. He died on March 17, 1853 in Venice. The effect bearing his name was first announced in a presentation before the Royal Bohemian Society of the Sciences in Prague on May 25, 1842. Doppler considered his work a generalization of the aberration theorem as discovered by Bradley. With it came the inference that the perception of physical phenomena can change with the state of motion of the observer. Acceptance of the principle was not without controversy. In 1852, the mathematician Petzval claimed that no useful scientific deductions can be made from Doppler's elementary equations. In 1860, Ernst Mach resolved the misunderstanding that clouded this controversy. The Doppler effect is alive and well. Its role in radio science and related disciplines is enumerated.

  9. Doppler weather radar; Doppler kisho radar

    Energy Technology Data Exchange (ETDEWEB)

    Adachi, H.; Sato, Y. [Toshiba Corp., Tokyo (Japan)

    2000-05-01

    Conventional weather radar transmits high-frequency pulses from the transmitter, and only observes the intensity of echoes reflected back from raindrops. Due to recent technological advancements in signal processing, data processing, and other fields, the capability to detect echo velocity, or Doppler velocity, based on this raindrop movement has been achieved. Processing of this Doppler velocity has enabled the system to provide more sophisticated weather information on downbursts, three-dimensional wind direction and velocity, and other weather phenomena. (author)

  10. [Principles of Doppler sonography].

    Science.gov (United States)

    Jenderka, K-V; Delorme, S

    2015-07-01

    The techniques of medical Doppler are spectral Doppler (contiuous-wave (CW) and pulse-wave (PW) Doppler) and color flow imaging (Color Doppler and Power Doppler). All are based on the fact that the frequency of an echo from a moving reflecting particle will be altered by a characteristic frequency shift determined by its velocity in relation to the source/detector. The CW Doppler will only detect flow within a pre-defined depth and will not be guided by an image, whereas the PW Doppler is carried out with B-mode guidance (Duplex doppler). The so derived curves permit to assess the temporal distribution of flow velocities and directions and flow disturbances as well. In the case of color flow imaging, a part of the interrogated tissue section is mapped for Doppler signals and then color-coded, resulting in a dynamic color map of flow, where the colors encode characteristic flow parameters (e. g. mean flow velocity plus direction). This article describes the technical and physical basics of medical Doppler techniques. PMID:26187613

  11. Soil and building material as main sources of indoor radon in B?i?a-?tei radon prone area (Romania)

    International Nuclear Information System (INIS)

    Radon contributes to over than 50% of the natural radiation dose received by people. In radon risk areas this contribution can be as high as 90–95%, leading to an exposure to natural radiation 5–10 times higher than normal. This work presents results from radon measurements (indoor, soil and exhalation from building materials) in B?i?a-?tei, a former uranium exploitation area in NW Romania. In this region, indoor radon concentrations found were as high as 5000 Bq m?3 and soil radon levels ranged from 20 to 500 kBq m?3. An important contribution from building materials to indoor radon was also observed. Our results indicate two independent sources of indoor radon in the surveyed houses of this region. One source is coming from the soil and regular building materials, and the second source being uranium waste and local radium reached material used in building construction. The soil as source of indoor radon shows high radon potential in 80% of the investigated area. Some local building materials reveal high radon exhalation rate (up to 80 mBq kg?1 h?1 from a sandy-gravel material, ten times higher than normal material). These measurements were used for the radon risk classification of this area by combining the radon potential of the soil with the additional component from building materials. Our results indicate that B?i?a-?tei area can be categorized as a radon prone area.

  12. Tendinopathy and Doppler activity

    DEFF Research Database (Denmark)

    Boesen, M I; Koenig, M J; Torp-Pedersen, S; Bliddal, H; Langberg, Henning

    2006-01-01

    Intratendinous Doppler activity has been interpreted as an equivalent of neovessels in the Achilles tendon and as a sign of tendinosis (AT).......Intratendinous Doppler activity has been interpreted as an equivalent of neovessels in the Achilles tendon and as a sign of tendinosis (AT)....

  13. Ultrasonic colour Doppler imaging

    DEFF Research Database (Denmark)

    Evans, David H; Jensen, Jørgen Arendt; Nielsen, Michael Bachmann

    2011-01-01

    Ultrasonic colour Doppler is an imaging technique that combines anatomical information derived using ultrasonic pulse-echo techniques with velocity information derived using ultrasonic Doppler techniques to generate colour-coded maps of tissue velocity superimposed on grey-scale images of tissue...... anatomy. The most common use of the technique is to image the movement of blood through the heart, arteries and veins, but it may also be used to image the motion of solid tissues such as the heart walls. Colour Doppler imaging is now provided on almost all commercial ultrasound machines, and has been...... vectors. This review briefly introduces the principles behind colour Doppler imaging and describes some clinical applications. It then describes the basic components of conventional colour Doppler systems and the methods used to derive velocity information from the ultrasound signal. Next, a number of new...

  14. Differential doppler heterodyning technique

    DEFF Research Database (Denmark)

    Lading, Lars

    1971-01-01

    Measuring velocity without disturbing the moving object is possible by use of the laser doppler heterodyning technique. Theoretical considerations on the doppler shift show that the antenna property of the photodetector can solve an apparent conflict between two different ways of calculating the...... detected doppler frequency. It is found that the doppler frequency for this particular setup is independent of the direction of detection. Investigations of the signal-to-noise ratio (SNR) show that the maximum SNR-considering the optical setup-is obtained by measuring the frequency difference between two...... doppler-shifted beams rather than by measuring the shift of a single beam by comparing it with a reference beam. Measurements seem to be in agreement with the theoretical consideration...

  15. Doppler radar flowmeter

    Energy Technology Data Exchange (ETDEWEB)

    Petlevich, Walter J. (Uniontown, PA); Sverdrup, Edward F. (Adamsburg, PA)

    1978-01-01

    A Doppler radar flowmeter comprises a transceiver which produces an audio frequency output related to the Doppler shift in frequency between radio waves backscattered from particulate matter carried in a fluid and the radiated radio waves. A variable gain amplifier and low pass filter are provided for amplifying and filtering the transceiver output. A frequency counter having a variable triggering level is also provided to determine the magnitude of the Doppler shift. A calibration method is disclosed wherein the amplifier gain and frequency counter trigger level are adjusted to achieve plateaus in the output of the frequency counter and thereby allow calibration without the necessity of being able to visually observe the flow.

  16. Doppler Lidar (DL) Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Newsom, RK

    2012-02-13

    The Doppler lidar (DL) is an active remote sensing instrument that provides range- and time-resolved measurements of radial velocity and attenuated backscatter. The principle of operation is similar to radar in that pulses of energy are transmitted into the atmosphere; the energy scattered back to the transceiver is collected and measured as a time-resolved signal. From the time delay between each outgoing transmitted pulse and the backscattered signal, the distance to the scatterer is inferred. The radial or line-of-sight velocity of the scatterers is determined from the Doppler frequency shift of the backscattered radiation. The DL uses a heterodyne detection technique in which the return signal is mixed with a reference laser beam (i.e., local oscillator) of known frequency. An onboard signal processing computer then determines the Doppler frequency shift from the spectra of the heterodyne signal. The energy content of the Doppler spectra can also be used to determine attenuated backscatter.

  17. Ultrasonic colour Doppler imaging

    DEFF Research Database (Denmark)

    Evans, David H.; Jensen, Jørgen Arendt; Nielsen, Michael Bachmann

    2011-01-01

    Ultrasonic colour Doppler is an imaging technique that combines anatomical information derived using ultrasonic pulse-echo techniques with velocity information derived using ultrasonic Doppler techniques to generate colour-coded maps of tissue velocity superimposed on grey-scale images of tissue anatomy. The most common use of the technique is to image the movement of blood through the heart, arteries and veins, but it may also be used to image the motion of solid tissues such as the heart walls...

  18. Rotational Doppler Effect

    OpenAIRE

    Halder, Amit

    2002-01-01

    A monochromatic linear source of light is rotated with certain angular frequency and when such light is analysed after reflection then a change of frequency or wavelength may be observed depending on the location of the observer. This change of frequency or wavelength is different from the classical Doppler effect [1] or relativistic Doppler effect [2]. The reason behind this shift in wavelength is that a certain time interval observed by an observer in the rotating frame is...

  19. Cosmology with Doppler Lensing

    OpenAIRE

    Bacon, David J.; Andrianomena, Sambatra; Clarkson, Chris; Bolejko, Krzysztof; Maartens, Roy

    2014-01-01

    Doppler lensing is the apparent change in object size and magnitude due to peculiar velocities. Objects falling into an overdensity appear larger on its near side, and smaller on its far side, than typical objects at the same redshifts. This effect dominates over the usual gravitational lensing magnification at low redshift. Doppler lensing is a promising new probe of cosmology, and we explore in detail how to utilize the effect with forthcoming surveys. We present cosmologi...

  20. The least-squares mixing models to generate fraction images derived from remote sensing multispectral data

    Science.gov (United States)

    Shimabukuro, Yosio Edemir; Smith, James A.

    1991-01-01

    Constrained-least-squares and weighted-least-squares mixing models for generating fraction images derived from remote sensing multispectral data are presented. An experiment considering three components within the pixels-eucalyptus, soil (understory), and shade-was performed. The generated fraction images for shade (shade image) derived from these two methods were compared by considering the performance and computer time. The derived shade images are related to the observed variation in forest structure, i.e., the fraction of inferred shade in the pixel is related to different eucalyptus ages.

  1. Right ventricular tissue Doppler assessment in space during circulating volume modification using the Braslet device

    Science.gov (United States)

    Hamilton, D. R.; Alferova, I. V.; Sargsyan, A. E.; Fincke, E. M.; Magnus, S. H.; Lonchakov, Y. V.; Dulchavsky, S. A.; Ebert, D.; Garcia, K.; Martin, D.; Matveev, V. P.; Voronkov, Y. I.; Melton, S. L.; Bogomolov, V. V.; Duncan, J. M.

    2011-05-01

    Introduction: This joint US-Russian work aims to establish a methodology for assessing cardiac function in microgravity in association with manipulation of central circulating volume. Russian Braslet-M (Braslet) occlusion cuffs were used to temporarily increase the volume of blood in the lower extremities, effectively reducing the volume in central circulation. The methodology was tested at the International Space Station (ISS) to assess the volume status of crewmembers by evaluating the responses to application and release of the cuffs, as well as to modified Valsalva and Mueller maneuvers. This case study examines the use of tissue Doppler (TD) of the right ventricular (RV) free wall. Results: Baseline TD of the RV free wall without Braslet showed early diastolic E' (16 cm/s), late diastolic A' (14 cm/s), and systolic S' (12 cm/s) velocities comparable with those in normal subjects on Earth. Braslet application caused 50% decrease of E' (8 cm/s), 45% increase of A', and no change to S'. Approximately 8 beats after the Braslet release, TD showed E' of 8 cm/s, A' of 12 cm/s, and S' of 13 cm/s. At this point after release, E' did not recover to baseline values while l A' and S' did recover. The pre-systolic cross-sectional area of the internal jugular vein without Braslet was 1.07 cm 2, and 1.13 cm 2 10 min after the Braslet was applied. The respective cross-sectional areas of the femoral vein were 0.50 and 0.54 cm 2. The RV myocardial performance Tei index was calculated by dividing the sum of the isovolumic contraction time and isovolumic relaxation time by the ejection time ((IVCT+IVRT)/ET); baseline and Braslet-on values for Tei index were 0.25 and 0.22, respectively. Braslet Tei indices are within normal ranges found in healthy terrestrial subjects and temporarily become greater than 0.4 during the dynamic Braslet release portion of the study. Conclusions: TD modality was successfully implemented in space flight for the first time. TD of RV revealed that the Braslet influenced cardiac preload and that fluid was sequestered in the lower extremity interstitial and vascular space after only 10 min of application. This report demonstrates that Braslet application has an effect on RV physiology in long-duration space flight based on TD, and that this effect is in part due to venous hemodynamics.

  2. Right Ventricular Tissue Doppler Assessment in Space During Circulating Volume Modification using the Braslet-M Device

    Science.gov (United States)

    Hamilton, D. R.; Sargsyan, A. E.; Fincke, E. M.; Magnus, S. H.; Lonchakov, Y. V.; Alferova, I. V.; Dulchavsky, S. A.; Ebert, D.; Garcia, K.; Martin, D.; Matveev, V. P.; Voronkov, Y. I.; Melton, S. L.; Duncan, J. M.; Bogomolov, V. V.

    2009-01-01

    This joint U.S. - Russian work aims to establish a methodology for assessing cardiac function in microgravity in association with manipulation of central circulating volume. Russian Braslet-M occlusion cuffs were used to temporarily increase the volume of blood in the lower extremities, which effectively reduces the volume returning to the heart in the central circulation. A novel methodology was tested on the International Space Station (ISS) to assess the volume status of crewmembers by evaluating the responses to application and release of the Braslet-on-occlusion cuffs, as well as to modified Valsalva and Mueller maneuvers. Baseline echocardiographic tissue Doppler imaging (TDI) of the right ventricular free wall with no Braslet applied shows early diastolic E' (16 cm/sec), late diastolic A' (14 cm/sec), and systolic (12 cm/sec) velocities compatible with normal subjects on Earth. TDI of the RV free wall with Braslet applied shows that early diastolic E' decreased by 50% (8 cm/sec), late diastolic A' increased by 45%, and systolic S' remains unchanged. TDI of the RV free wall approximately 8 beats after the Braslet was released shows early diastolic E' (8 cm/sec), late diastolic A' (12 cm/sec), and systolic S' (13 cm/sec) velocities. During this portion of the release, early diastolic E' did not recover to baseline values but late diastolic A' and systolic S' recovered to pre-Braslet values. The pre-systolic cross-sectional area of the internal jugular vein with Braslet off was 1.07 cm(sup 2) and 1.13 cm(sup 2) 10 min after the Braslet was applied. The presystolic cross-sectional area of the common femoral vein with Braslet off was 0.50 cm(sup 2), and was 0.54 cm(sup 2) 10 min after the Braslet was applied. The right ventricular myocardial performance Tei index also was calculated for comparison with typical values found in healthy subjects on Earth. Baseline and Braslet-on values for Tei index were 0.25 and 0.22 respectively. Braslet Tei indices are within normal ranges found in healthy subjects and temporarily become greater than 0.4 during the dynamic Braslet release portion of this study. Tissue Doppler imaging of the right ventricle revealed that the Braslet influenced cardiac preload and that fluid was sequestered in the lower-extremity interstitial and vascular space after only 10 minutes of application. This report demonstrates that Braslet application affects right ventricular physiology in long-duration space flight based on TDI and that this effect is in part due to venous hemodynamics.

  3. Doppler radar flowmeter

    Energy Technology Data Exchange (ETDEWEB)

    Petlevich, W.J.; Sverdrup, E.F.

    1978-05-23

    A Doppler radar flowmeter is described. It consists of a transceiver which produces an ausio frequency output related to the Doppler shift in frequency between radio waves backscattered from particulate matter carried in a fluid and the radiated radio waves. A variable gain amplifier and low pass filter are provided for amplifying and filtering the transceiver output. A frequency counter having a variable triggering level is provided to determine the magnitude of the Doppler shift. A calibration method is disclosed wherein the amplifier gain and frequency counter trigger level are adjusted to achieve plateaus in the output of the frequency counter and allow calibration without the necessity of being able to visually observe the flow.

  4. Pulse Doppler radar

    CERN Document Server

    Alabaster, Clive

    2012-01-01

    This book is a practitioner's guide to all aspects of pulse Doppler radar. It concentrates on airborne military radar systems since they are the most used, most complex, and most interesting of the pulse Doppler radars; however, ground-based and non-military systems are also included. It covers the fundamental science, signal processing, hardware issues, systems design and case studies of typical systems. It will be a useful resource for engineers of all types (hardware, software and systems), academics, post-graduate students, scientists in radar and radar electronic warfare sectors and milit

  5. Doppler ion program description

    International Nuclear Information System (INIS)

    The Doppler spectrometer is a conventional Czerny-Turner grating spectrometer with a 1024 channel multiple detector. Light is dispersed across the detector, and its output yields a spectrum covering approximately 200 A. The width of the spectral peak is directly proportional to the temperature of the emitting ions, and determination of the impurity ion temperature allows one to infer the plasma ion temperature. The Doppler ion software system developed at General Atomic uses a TRACOR Northern 1710-31 and an LSI-11/2. The exact configuration of Doublet III is different from TRACOR Northern systems at other facilities

  6. Doppler-musical instrument

    International Nuclear Information System (INIS)

    We propose a possible ultra-high energy resolution backscattering spectrometer optimized to spallation neutron source. A combination of multi monochromator crystal and Doppler drive provides considerable neutron flux, together with the reasonable energy range -30 < E < 30 μeV, even when the ultra-high energy resolution of ΔE∼0.03 μeV is attained. (author)

  7. Testing radon mitigation techniques in a pilot house from B?i?a-?tei radon prone area (Romania)

    International Nuclear Information System (INIS)

    This work presents the implementation and testing of several radon mitigation techniques in a pilot house in the radon prone area of B?i?a-?tei in NW part of Romania. Radon diagnostic investigations in the pilot house showed that the main source of radon was the building sub-soil and the soil near the house. The applied techniques were based on the depressurization and pressurization of the building sub-soil, on the combination of the soil depressurization system by an electric and an eolian fans. Also, there was made an application of a radon barrier membrane and a testing by the combination of the radon membrane by the soil depressurization system. Finally, the better obtained remedial efficiency was about 85%. - Highlights: • It is presents testings of most effective radon mitigation techniques in a pilot house, from a radon prone area (NW of Romania). • Diagnostic investigations showed that the main radon sources were the building sub-soil. • The applied techniques were based on the depressurization and pressurization of the building sub-soil, by an electric and eolian fans. • A radon barrier membrane was applyed and tested in the combination by the soil depressurization system. • The efficiency by the whole mitigation was about 85%

  8. Doppler radar results

    Science.gov (United States)

    Bracalente, Emedio M.

    1992-01-01

    The topics are covered in viewgraph form and include the following: (1) a summary of radar flight data collected; (2) a video of combined aft cockpit, nose camera, and radar hazard displays; (3) a comparison of airborne radar F-factor measurements with in situ and Terminal Doppler Weather Radar (TDWR) F-factors for some sample events; and (4) a summary of wind shear detection performance.

  9. Holographic laser Doppler ophthalmoscopy

    CERN Document Server

    Simonutti, Manuel; Sahel, J A; Gross, Michel; Samson, Benjamin; Magnain, Caroline; Atlan, Michael; 10.1364/OL.35.001941

    2010-01-01

    We report laser Doppler ophthalmoscopic fundus imaging in the rat eye with near-IR heterodyne holography. Sequential sampling of the beat of the reflected radiation against a frequency-shifted optical local oscillator is made onto an array detector. Wide-field maps of fluctuation spectra in the 10 Hz to 25 kHz band exhibit angiographic contrasts in the retinal vascular tree without requirement of an exogenous marker.

  10. Laser double Doppler flowmeter

    Science.gov (United States)

    Poffo, L.; Goujon, J.-M.; Le Page, R.; Lemaitre, J.; Guendouz, M.; Lorrain, N.; Bosc, D.

    2014-05-01

    The Laser Doppler flowmetry (LDF) is a non-invasive method for estimating the tissular blood flow and speed at a microscopic scale (microcirculation). It is used for medical research as well as for the diagnosis of diseases related to circulatory system tissues and organs including the issues of microvascular flow (perfusion). It is based on the Doppler effect, created by the interaction between the laser light and tissues. LDF measures the mean blood flow in a volume formed by the single laser beam, that penetrate into the skin. The size of this measurement volume is crucial and depends on skin absorption, and is not directly reachable. Therefore, current developments of the LDF are focused on the use of always more complex and sophisticated signal processing methods. On the other hand, laser Double Doppler Flowmeter (FL2D) proposes to use two laser beams to generate the measurement volume. This volume would be perfectly stable and localized at the intersection of the two laser beams. With FL2D we will be able to determine the absolute blood flow of a specific artery. One aimed application would be to help clinical physicians in health care units.

  11. Automated measurement of fetal myocardial performance index in ultrasound Doppler waveforms

    Science.gov (United States)

    Yoon, Heechul; Lee, Hyuntaek; Jeon, Kang-Won; Jung, Haekyung; Lee, Mi-Young; Won, Hye-Sung; Jeon, Eun-Jin; Yang, Eun-Ho; Choi, Jin-Young; Hong, Soon-Jae

    2014-03-01

    We introduce an automated method for myocardial performance index (MPI), also known as Tei index, which is one of the most substantial indicators in the early screening of heart defects. Since assessing fetal cardiac functions using MPI has become a routine and significant process, there have been explicit requirements to automate MPI measurements. Due to small heart sizes of fetuses, we focus on the automation of modified MPI (Mod-MPI) which uses a single Doppler gate. The proposed method detects four valve click signals in Doppler waveforms using four image features which are extracted by vertical projection of Doppler waveforms after several transformations. To evaluate performance, 88 of fetal examinations were collected from a commercial ultrasound machine, and two clinical experts measured the Mod-MPI both manually and automatically. Quantitative comparisons based on intra-class correlation coefficients (ICC) yield that intra-observer reproducibility is higher when performing the proposed method (ICC=0.951 and 0.932 for observer 1 and 2) comparing to those of manual measurements (ICC=0.868 and 0.857 for observer 1 and observer 2). Thus, our method (ICC=0.962) reveals superior inter-observer reproducibility than that of manual method (ICC=0.597). Although mean difference from observer 2 (-0.062) is over three times larger than that of observer 1 (-0.018) due to different experiences, both of mean differences are acceptable. In conclusion, the proposed MPI measurement method can improve intra- and inter-reproducibility while providing reliable results.

  12. Clinical applications of doppler ultrasound

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, K.J.W.; Burns, P.N.; Well, P.N.T.

    1987-01-01

    This book introduces a guide to the physical principles and instrumentation of duplex Doppler ultrasound and its applications in obstetrics, gynecology, neonatology, gastroentology, and evaluation of peripheral vascular disease. The book provides information needed to perform Doppler ultrasound examinations and interpret the results. An introduction to Doppler physics and instrumentation is followed by a thorough review of hemodynamics, which explains the principles underlying interpretation of Doppler signals. Of special note is the state-of-the-art coverage of new applications of Doppler in recognition of high-risk pregnancy, diagnosis of intrauterine growth retardation, investigation of neonatal blood flow, evaluation of first-trimester pregnancy, and diagnosis of gastrointestinal disease. The book also offers guidelines on the use of Doppler ultrasound in diagnosing carotid disease, deep venous thrombosis, and aorta/femoral disease.

  13. Zu lexikalisch-semantischen Problemen bei der Erstellung eines Fachglossars.Vorgestellt am Deutschen und Litauischen Urheberrecht. Termin? žodyn?lio sudarymo leksin?s semantikos problemos Vokietijos ir Lietuvos autori? teis?s kontekste

    Directory of Open Access Journals (Sweden)

    Aust?ja Galginaityt?

    2007-01-01

    Full Text Available Das Ziel dieses Beitrages ist es, die beim Erstellungsprozess eines Fachglossars zum deutschen und litauischen Urheberrecht deutlich gewordenen lexikalisch-semantischen Schwierigkeiten zu besprechen und u. a. zu zeigen, wie die festgestellten Besonderheiten in einem zweisprachigen Fachglossar berücksichtigt werden können.----- Straipsnyje aptariamos leksin?s semantikos problemos, kilusios sudarant dvikalb? Vokietijos ir Lietuvos autori? teis?s termin? žodyn?l? bei pateikiami pasi?lymai, kaip pasteb?ti ypatumai gal?t? (ir tur?t? b?ti atspindimi terminografiniuose darbuose. Su termin? semantika susijusios problemos išryšk?ja tiriant kai kurias pasirinktos srities termin? semantines savybes – analizuojant ?vairius apibr?ž?i? tipus, termin? tikslum? bei vienareikšmiškum?. Nustatyta, kad autori? teis?s termin? apibr?žtys ne visada atitinka apibr?ž?i? rašymo principus (pvz., kartais yra nepilnos. Be to, nagrin?tos srities terminijai b?dingi sinonimijos bei polisemijos reiškiniai. Sinonimija gali b?ti paaiškinama tuo, kad, pavyzdžiui, Europos S?jungos teis?s aktuose vartojam? terminij? galima laikyti savarankiška teis?s terminija, o polisemij? – tuo, kad min?tuose teis?s aktuose vartojam? t? pa?i? termin? turinys ne visada yra vienodas. Daroma išvada, kad teis?s dalykinei kalbai svarbus komunikacin?s situacijos kotekstas ir kontekstas, d?l ko yra pateisinama, kad sudarant žodyn?l? b?t? atsižvelgiama ir ? neb?tinai visiškai tikslius, vienareikšmius terminus bei (terminologiniu poži?riu vertinant ydingas apibr?žtis, pateikiamas tiriamos teis?s srities tekstuose. Sudarant termin? žodyn?l? kiekviename jo straipsnyje reik?t? stengtis pateikti kuo daugiau papildomos informacijos apie termin? (galimas kelias – nacionaliniuose, Europos S?jungos ir tarptautiniuose teis?s aktuose pateikiamas – jo apibr?žtis, vartojimo kontekste pavyzdžius, komentarus ir pan. tam, kad adresatas šia informacija remdamasis kuo geriau ir grei?iau gal?t? ?vertinti, ar si?lomas vertimo variantas yra tinkamas konkre?ioje komunikacin?je situacijoje.

  14. Laser doppler perfusion imaging

    International Nuclear Information System (INIS)

    Recording of tissue perfusion is important in assessing the influence of peripheral vascular diseases on the microcirculation. This thesis reports on a laser doppler perfusion imager based on dynamic light scattering in tissue. When a low power He-Ne laser beam sequentally scans the tissue, moving blood cells generate doppler components in the back-scattered light. A fraction of this light is detected by a photodetector and converted into an electrical signal. In the processor, a signal proportional to the tissue perfusion at each measurement site is calculated and stored. When the scanning procedure is completed, a color-coded perfusion image is presented on a monitor. To convert important aspects of the perfusion image into more quantitative parameters, data analysis functions are implemented in the software. A theory describing the dependence of the distance between individual measurement points and detector on the system amplification factor is proposed and correction algorithms are presented. The performance of the laser doppler perfusion imager was evaluated using a flow simulator. A linear relationship between processor output signal and flow through the simulator was demonstrated for blood cell concentrations below 0.2%. The median sampling depth of the laser beam was simulated by a Monte Carlo technique and estimated to 235 μm. The perfusion imager has been used in the clinic to study perfusion changes in port wine stains treated with argon laser and to investigate the intensity and extension of the cutaneous axon reflex response after electrical nerve stimulation. The fact that perfusion can be visualized without touching the tissue implies elimination of sterilization problems, thus simplifying clinical investigations of perfusion in association with diagnosis and treatment of peripheral vascular diseases. 22 refs

  15. A Multimodal Approach to Image-Derived Input Functions for Brain PET

    OpenAIRE

    Fung, Edward K.; Planeta-Wilson, Beata; Mulnix, Tim; Carson, Richard E.

    2009-01-01

    Many methods have been proposed for generating an image-derived input function (IDIF) exclusively from PET images. The purpose of this study was to assess the viability of a multimodality approach utilizing registered MR images. 3T-MR and HRRT-PET data were acquired from human subjects. Segmentation of both the left and right carotid arteries was performed in MR images using a 3D level sets method. Vessel centerlines were extracted by parameterization of the segmented voxel coordinates with e...

  16. Comparisons between PW Doppler system and enhanced FM Doppler system

    DEFF Research Database (Denmark)

    Wilhjelm, Jens E.; Pedersen, P. C.

    This paper presents a new implementation of an echo-ranging FM Doppler system with improved performance, relative to the FM Doppler system reported previously. The use of long sweeps provides a significant reduction in peak to average power ratio compared to pulsed wave (PW) emission. A PW Doppler...... system exploits the direct relationship between arrival time of the received signal and range from the transducer. In the FM Doppler systems, a similar relationship exists in the spectral domain of the demodulated received signals, so that range is represented by frequency. Thus, a shift in location of...... moving scatterers between consecutive emissions corresponds to a frequency shift in the spectral signature. The improvement relative to the earlier version of the FM Doppler system is attained by utilizing cross-correlation of real spectra rather than of magnitude spectra for assessing flow velocity...

  17. ANL Doppler flowmeter

    Energy Technology Data Exchange (ETDEWEB)

    Karplus, H.B.; Raptis, A.C.; Lee, S.; Simpson, T.

    1985-10-01

    A flowmeter has been developed for measuring flow velocity in hot slurries. The flowmeter works on an ultrasonic Doppler principle in which ultrasound is injected into the flowing fluid through the solid pipe wall. Isolating waveguides separate the hot pipe from conventional ultrasonic transducers. Special clamp-on high-tempreature transducers also can be adapted to work well in this application. Typical flows in pilot plants were found to be laminar, giving rise to broad-band Doppler spectra. A special circuit based on a servomechanism sensor was devised to determine the frequency average of such a broad spectrum. The device was tested at different pilot plants. Slurries with particulates greater than 70 m (0.003 in.) yielded good signals, but slurries with extremely fine particulates were unpredictable. Small bubbles can replace the coarse particles to provide a good signal if there are not too many. Successful operation with very fine particulate slurries may have been enhanced by the presence of microbubbles. 11 refs., 46 figs., 3 tabs.

  18. Principles of doppler tomography

    International Nuclear Information System (INIS)

    This paper shows how the radon transform can be used to determine vector fields. A scheme to determine the velocity field of a moving fluid by measurements with a continuous doppler signal is suggested. When the flow is confined to a bounded domain, as is the case in most applications, it can be uniquely decomposed into one gradiental and one rotational part. The former vanishes if the fluid is incompressible and source-free, and the latter can be completely reconstructed by the methods proposed in this paper if the domain is simply connected. Special attention is paid to laminar flow in a long cylindrical vessel with circular cross-section. Under such conditions the flow profile becomes parabolic, which makes the vessel recognizable as a typical 'N-shaped' pattern in an image describing the rotation of the velocity field. The vessel yields the same doppler tomographic pattern, no matter how it is sectioned. The ideas presented should be applicable also when studying the flow in blood vessels, even if the flow profile in these is not quite parabolic. The discrepancies only make the 'N-shape' somewhat distorted

  19. Doppler Beats or Interference Fringes?

    Science.gov (United States)

    Kelly, Paul S.

    1979-01-01

    Discusses the following: another version of Doppler beats; alternate proof of spin-1 sin-1/2 problems; some mechanisms related to Dirac's strings; Doppler redshift in oblique approach of source and observer; undergraduate experiment on noise thermometry; use of the time evolution operator; resolution of an entropy maximization controversy;…

  20. Determination of the Accuracy of Echocardiographic Parameters Mitral Inflow S/D Ratio and Tei Index to Detect Left Ventricular Dysfunction in Pediatric Patients with Mitral Regurgitation

    Directory of Open Access Journals (Sweden)

    Mohammad Hossein Arjmandnia

    2013-02-01

    Full Text Available Background and Objectives: Congenital heart diseases are one of the most common anomalies in infancy. This study was performed aimed to determine the accuracy, sensitivity and specificity of the left ventricular Tei index (TX and the systolic to diastolic duration ratio (S/D to detect ventricular dysfunction in pediatric pediatrics with congenital heart defect accompanied by mitral regurgitation.Methods: In this study, systolic and diastolic function of left ventricle was evaluated by TX and S/D ratio parameters in 66 children with mitral regurgitation (34 children with normal ventricular function and 32 patients with ventricular dysfunction and the results were compared to the findings of echocardiography. Tei index>0.5 was defined as abnormal.Results: The accuracy, sensitivity, specificity, positive and negative predictive values of S/D ratio were obtained 89.3%, 87.5%, 91%, 90% and 88.5%, respectively and for TX, 87.8%, 87.5%, 88.2%, 87.5% and 88.2%, respectively.Conclusion: The results of this study showed that in general, accuracy, sensitivity, specificity, predictive values, and likelihood ratios of TX are less than those of S/D ratio in patients with congenital heart defect accompanied by mitral regurgitation.

  1. Adaptive Spectral Doppler Estimation

    DEFF Research Database (Denmark)

    Gran, Fredrik; Jakobsson, Andreas; Jensen, Jørgen Arendt

    2009-01-01

    In this paper, 2 adaptive spectral estimation techniques are analyzed for spectral Doppler ultrasound. The purpose is to minimize the observation window needed to estimate the spectrogram to provide a better temporal resolution and gain more flexibility when designing the data acquisition sequence....... The methods can also provide better quality of the estimated power spectral density (PSD) of the blood signal. Adaptive spectral estimation techniques are known to pro- vide good spectral resolution and contrast even when the ob- servation window is very short. The 2 adaptive techniques are tested and...... compared with the averaged periodogram (Welch’s method). The blood power spectral capon (BPC) method is based on a standard minimum variance technique adapted to account for both averaging over slow-time and depth. The blood amplitude and phase estimation technique (BAPES) is based on finding a set of...

  2. Adaptive Spectral Doppler Estimation

    DEFF Research Database (Denmark)

    Gran, Fredrik; Jakobsson, Andreas; Jensen, Jørgen Arendt

    2009-01-01

    In this paper, 2 adaptive spectral estimation techniques are analyzed for spectral Doppler ultrasound. The purpose is to minimize the observation window needed to estimate the spectrogram to provide a better temporal resolution and gain more flexibility when designing the data acquisition sequence....... The methods can also provide better quality of the estimated power spectral density (PSD) of the blood signal. Adaptive spectral estimation techniques are known to pro- vide good spectral resolution and contrast even when the ob- servation window is very short. The 2 adaptive techniques are tested and...... compared with the averaged periodogram (Welch’s method). The blood power spectral capon (BPC) method is based on a standard minimum variance technique adapted to account for both averaging over slow-time and depth. The blood amplitude and phase estimation technique (BAPES) is based on finding a set of...

  3. Assessment of image-derived risk factors for natural course of unruptured cerebral aneurysms.

    Science.gov (United States)

    Ramachandran, Manasi; Retarekar, Rohini; Raghavan, Madhavan L; Berkowitz, Benjamin; Dickerhoff, Benjamin; Correa, Tatiana; Lin, Steve; Johnson, Kevin; Hasan, David; Ogilvy, Christopher; Rosenwasser, Robert; Torner, James; Bogason, Einar; Stapleton, Christopher J; Harbaugh, Robert E

    2016-02-01

    OBJECT The goal of this prospective longitudinal study was to test whether image-derived metrics can differentiate unruptured aneurysms that will become unstable (grow and/or rupture) from those that will remain stable. METHODS One hundred seventy-eight patients harboring 198 unruptured cerebral aneurysms for whom clinical observation and follow-up with imaging surveillance was recommended at 4 clinical centers were prospectively recruited into this study. Imaging data (predominantly CT angiography) at initial presentation was recorded. Computational geometry was used to estimate numerous metrics of aneurysm morphology that described the size and shape of the aneurysm. The nonlinear, finite element method was used to estimate uniform pressure-induced peak wall tension. Computational fluid dynamics was used to estimate blood flow metrics. The median follow-up period was 645 days. Longitudinal outcome data on these aneurysm patients-whether their aneurysms grew or ruptured (the unstable group) or remained unchanged (the stable group)-was documented based on follow-up at 4 years after the beginning of recruitment. RESULTS Twenty aneurysms (10.1%) grew, but none ruptured. One hundred forty-nine aneurysms (75.3%) remained stable and 29 (14.6%) were lost to follow-up. None of the metrics-including aneurysm size, nonsphericity index, peak wall tension, and low shear stress area-differentiated the stable from unstable groups with statistical significance. CONCLUSIONS The findings in this highly selected group do not support the hypothesis that image-derived metrics can predict aneurysm growth in patients who have been selected for observation and imaging surveillance. If aneurysm shape is a significant determinant of invasive versus expectant management, selection bias is a key limitation of this study. PMID:26381246

  4. Dual-Doppler Feasibility Study

    Science.gov (United States)

    Huddleston, Lisa L.

    2012-01-01

    When two or more Doppler weather radar systems are monitoring the same region, the Doppler velocities can be combined to form a three-dimensional (3-D) wind vector field thus providing for a more intuitive analysis of the wind field. A real-time display of the 3-D winds can assist forecasters in predicting the onset of convection and severe weather. The data can also be used to initialize local numerical weather prediction models. Two operational Doppler Radar systems are in the vicinity of Kennedy Space Center (KSC) and Cape Canaveral Air Force Station (CCAFS); these systems are operated by the 45th Space Wing (45 SW) and the National Weather Service Melbourne, Fla. (NWS MLB). Dual-Doppler applications were considered by the 45 SW in choosing the site for the new radar. Accordingly, the 45th Weather Squadron (45 WS), NWS MLB and the National Aeronautics and Space Administration tasked the Applied Meteorology Unit (AMU) to investigate the feasibility of establishing dual-Doppler capability using the two existing systems. This study investigated technical, hardware, and software requirements necessary to enable the establishment of a dual-Doppler capability. Review of the available literature pertaining to the dual-Doppler technique and consultation with experts revealed that the physical locations and resulting beam crossing angles of the 45 SW and NWS MLB radars make them ideally suited for a dual-Doppler capability. The dual-Doppler equations were derived to facilitate complete understanding of dual-Doppler synthesis; to determine the technical information requirements; and to determine the components of wind velocity from the equation of continuity and radial velocity data collected by the two Doppler radars. Analysis confirmed the suitability of the existing systems to provide the desired capability. In addition, it is possible that both 45 SW radar data and Terminal Doppler Weather Radar data from Orlando International Airport could be used to alleviate any radar geometry issues at the NWS MLB radar, such as the "cone of silence" or beam blockage. In the event of a radar outage at one of the sites, the multi-radar algorithms would provide continuing coverage of the area through use of the data from the remaining operational radar sites. There are several options to collect, edit, synthesize and display dual-Doppler data sets. These options include commercial packages available for purchase and a variety of freeware packages available from the National Center for Atmospheric Research (NCAR) for processing raw radar data. However, evaluation of the freeware packages revealed that they do not have sufficient documentation and configuration control to be certified for 45 SW use. Additionally, a TI data line must be installed/leased from the NWS MLB office and CCAFS to enable the receipt of NWS MLB raw radar data to use in the dual-Doppler synthesis. Integration of the TI data line into the Eastern Range infrastructure that will meet the security requirements necessary for 45 SW use is time-consuming and costly. Overall evaluation indicates that establishment of the dual-Doppler capability using the existing operational radar systems is desirable and feasible with no technical concerns. Installation of such a system represents a significant enhancement to forecasting capabilities at the 45 WS and at NWS MLB. However, data security and cost considerations must be evaluated in light of current budgetary constraints. In any case, gaining the dual-Doppler capability will provide opportunities for better visualization of the wind field and better forecasting of the onset of convection and severe weather events to support space launch operations at KSC and CCAFS.

  5. Transversal Doppler-Fizeau effect

    International Nuclear Information System (INIS)

    The relativistic calculation of the Doppler-Fizeau effect foresees a second grade redshift due to the proper time dilation of a moving object. The relevance of this relativistic effect on astrophysical observation is discussed, herein. (Auhor)

  6. Doppler characteristics of sea clutter.

    Energy Technology Data Exchange (ETDEWEB)

    Raynal, Ann Marie; Doerry, Armin Walter

    2010-06-01

    Doppler radars can distinguish targets from clutter if the target's velocity along the radar line of sight is beyond that of the clutter. Some targets of interest may have a Doppler shift similar to that of clutter. The nature of sea clutter is different in the clutter and exo-clutter regions. This behavior requires special consideration regarding where a radar can expect to find sea-clutter returns in Doppler space and what detection algorithms are most appropriate to help mitigate false alarms and increase probability of detection of a target. This paper studies the existing state-of-the-art in the understanding of Doppler characteristics of sea clutter and scattering from the ocean to better understand the design and performance choices of a radar in differentiating targets from clutter under prevailing sea conditions.

  7. Testing of Doppler Ultrasound Systems

    OpenAIRE

    Walker, Andrew

    2009-01-01

    Blood and tissue velocities are measured and analyzed in cardiac, vascular, and other applications of diagnostic ultrasound. Errors in system performance might give invalid measurements. We developed two moving string test targets and a rotating cylinder phantom (Doppler phantoms) to characterize Doppler ultrasound systems. These phantoms were initially used to measure such variables as sample volume dimensions, location of the sample volume, and the performance of the spectral analysis. Late...

  8. Relativistic Doppler-shift effects

    International Nuclear Information System (INIS)

    The lack of knowledge of relativistic distribution functions for interacting particles introduces uncertainty into the cosmological interpretation of Doppler shifts, particularly for systems such as quasars. Here we define an average Doppler shift, reducible to the nonrelativistic form in the appropriate limit. However, even for the relativistic ideal situation (Juettner distribution), second-order effects yield shift corrections after averaging. Such effects should be of interest for nuclear x-ray and ?-ray lines

  9. Adaptive Spectral Doppler Estimation

    DEFF Research Database (Denmark)

    Gran, Fredrik; Jakobsson, Andreas

    2009-01-01

    In this paper, 2 adaptive spectral estimation techniques are analyzed for spectral Doppler ultrasound. The purpose is to minimize the observation window needed to estimate the spectrogram to provide a better temporal resolution and gain more flexibility when designing the data acquisition sequence. The methods can also provide better quality of the estimated power spectral density (PSD) of the blood signal. Adaptive spectral estimation techniques are known to pro- vide good spectral resolution and contrast even when the ob- servation window is very short. The 2 adaptive techniques are tested and compared with the averaged periodogram (Welch’s method). The blood power spectral capon (BPC) method is based on a standard minimum variance technique adapted to account for both averaging over slow-time and depth. The blood amplitude and phase estimation technique (BAPES) is based on finding a set of matched filters (one for each veloc- ity component of interest) and filtering the blood process over slow-time and averaging over depth to find the PSD. The methods are tested using various experiments and simulations. First, controlled flow-rig experiments with steady laminar flow are carried out. Simulations in Field II for pul- sating flow resembling the femoral artery are also analyzed. The simulations are followed by in vivo measurement on the common carotid artery. In all simulations and experiments it was concluded that the adaptive methods display superior per- formance for short observation windows compared with the averaged periodogram. Computational costs and implementation details are also discussed.

  10. High Resolution Doppler Lidar

    Science.gov (United States)

    1996-01-01

    This Grant supported the development of an incoherent lidar system to measure winds and aerosols in the lower atmosphere. During this period the following activities occurred: (1) an active feedback system was developed to improve the laser frequency stability; (2) a detailed forward model of the instrument was developed to take into account many subtle effects, such as detector non-linearity; (3) a non-linear least squares inversion method was developed to recover the Doppler shift and aerosol backscatter without requiring assumptions about the molecular component of the signal; (4) a study was done of the effects of systematic errors due to multiple etalon misalignment. It was discovered that even for small offsets and high aerosol loadings, the wind determination can be biased by as much as 1 m/s. The forward model and inversion process were modified to account for this effect; and (5) the lidar measurements were validated using rawinsonde balloon measurements. The measurements were found to be in agreement within 1-2 m/s.

  11. Doppler weather radar; Saishin no kishokansoku gijutsu (kishoyo doppler radar)

    Energy Technology Data Exchange (ETDEWEB)

    Ishihara, M. [Meteorological Agency, Tokyo (Japan)

    1996-05-15

    The Doppler weather radar (DR) is described with the application of a precipitation phenomenon to observation as the principal object. The component along the kinetic vector`s radar beam of precipitation particles is measured using a Doppler weather radar (in which an electromagnetic wave of 3 to 10 cm is usually used). The air current in a precipitating cloud can be measured in three dimensions by the observation of a precipitating cloud using two Doppler weather radars that were located several ten kilometers away from each other. Therefore, the mechanism on the generation and growth of a precipitation phenomenon has been clarified by combining this observation and the numerical calculation on a precipitation phenomenon. The Doppler weather radar is also most suitable for the detection of a low-layer wind shear (microburst caused by the downward flow from a convective cloud, rapid change in a wind near the ground accompanying a cold front, etc.). To prevent aircraft from an accident, a plan in which Doppler weather radars are installed in the major airports of Japan has been promoted by the Japan Meteorological Agency. 3 figs.

  12. A Multimodal Approach to Image-Derived Input Functions for Brain PET

    Science.gov (United States)

    Fung, Edward K.; Planeta-Wilson, Beata; Mulnix, Tim; Carson, Richard E.

    2010-01-01

    Many methods have been proposed for generating an image-derived input function (IDIF) exclusively from PET images. The purpose of this study was to assess the viability of a multimodality approach utilizing registered MR images. 3T-MR and HRRT-PET data were acquired from human subjects. Segmentation of both the left and right carotid arteries was performed in MR images using a 3D level sets method. Vessel centerlines were extracted by parameterization of the segmented voxel coordinates with either a single polynomial curve or a B-spline curve fitted to the segmented data. These centerlines were subsequently re-registered to static PET data to maximize the accurate classification of PET voxels in the ROI. The accuracy of this approach was assessed by comparison of the area under the curve (AUC) of the IDIF to that measured from conventional automated arterial blood sampling. Our method produces curves similar in shape to that of blood sampling. The mean AUC ratio of the centerline region was 0.40±0.19 before re-registration and 0.69±0.26 after re-registration. Increasing the diameter of the carotid ROI produced a smooth reduction in AUC. Thus, even with the high resolution of the HRRT, partial volume correction is still necessary. This study suggests that the combination of PET information with MR segmented regions will demonstrate an improvement over regions based solely on MR or PET alone. PMID:20607124

  13. A Whiter Shade of Grey: A new approach to archaeological grey literature using the XML version of the TEI Guidelines

    Directory of Open Access Journals (Sweden)

    Gail Falkingham

    2005-04-01

    Full Text Available This article has arisen through the author's interest in two contemporary issues within archaeology: the production and dissemination of grey literature and the potential of XML. Grey literature is examined, with specific reference to unpublished reports literature produced in the present climate of developer-funded archaeology in England. There are concerns about the accessibility of this literature, both from within and beyond the archaeological profession. The vast majority of reports are word-processed and then printed in hard-copy format for limited distribution. The original, digital document however, has largely been seen as a by-product. Awareness of the importance of these digital reports, and their preservation must be raised. Electronic means of delivery and dissemination via the World Wide Web offer huge potential and present opportunities for new ways of working. Archaeology is not alone in seeking to promote the accessibility of grey literature; indeed there are many disciplines that have created online initiatives aiming to do just this, utilising a variety of means and a range of electronic file formats. The use of XML technology appears to offer many advantages over traditional formats, such as word-processed, PDF and even (XHTML files, particularly with regard to the manipulation and presentation of encoded electronic text. Increasingly, XML technology is being used for electronic delivery and dissemination and the pros and cons of so doing are discussed in this article. This theme has been developed by the author through a 'proof of concept' practical case study of three unpublished grey literature archaeology reports from the North Yorkshire Historic Environment Record. XML documents have been created from the original word-processed electronic reports by the manual application of XML markup, the methodology for which was devised following the XML version of the Text Encoding Initiative's TEI P4 Guidelines. The level of detail to which the reports' structure and content has been encoded has been influenced principally by a review of user needs identified by recent national surveys and the potential for export of data for the population of other heritage datasets. Through the application of CSS and XSL stylesheets, the case study demonstrates how the reports and their content may be displayed in different ways and how selected data may be extracted from the text for input into other systems, such as Historic Environment Records and the OASIS Project database. The author came to this project as a novice in the use of XML and XSLT, and learnt far more as the case study progressed. Whilst it has been possible to achieve the desired aims, it is acknowledged that this is just a starting point; more advanced users of XSLT will, no doubt, be able to produce more sophisticated ways of applying styling and transformation. Nevertheless, it is hoped that this exploration of the potential of archaeological document markup will encourage others to use and experiment with XML. The practical elements of this paper demonstrate how XML and XSLT have the power and flexibility to open up new possibilities for the presentation of grey literature on the Web, and for the repurposing of report content, above and beyond those achievable with the proprietary file formats favoured at present. There is national interest in, and call for, the development of new methods of electronic publication for archaeological reports; it is hoped that this article will contribute to this debate.

  14. Planetary Doppler Imaging

    Science.gov (United States)

    Murphy, N.; Jefferies, S.; Hart, M.; Hubbard, W. B.; Showman, A. P.; Hernandez, G.; Rudd, L.

    2014-12-01

    Determining the internal structure of the solar system's gas and ice giant planets is key to understanding their formation and evolution (Hubbard et al., 1999, 2002, Guillot 2005), and in turn the formation and evolution of the solar system. While internal structure can be constrained theoretically, measurements of internal density distributions are needed to uncover the details of the deep interior where significant ambiguities exist. To date the interiors of giant planets have been probed by measuring gravitational moments using spacecraft passing close to, or in orbit around the planet. Gravity measurements are effective in determining structure in the outer envelope of a planet, and also probing dynamics (e.g. the Cassini and Juno missions), but are less effective in probing deep structure or the presence of discrete boundaries. A promising technique for overcoming this limitation is planetary seismology (analogous to helioseismology in the solar case), postulated by Vorontsov, 1976. Using trapped pressure waves to probe giant planet interiors allows insight into the density and temperature distribution (via the sound speed) down to the planetary core, and is also sensitive to sharp boundaries, for example at the molecular to metallic hydrogen transition or at the core-envelope interface. Detecting such boundaries is not only important in understanding the overall structure of the planet, but also has implications for our understanding of the basic properties of matter at extreme pressures. Recent Doppler measurements of Jupiter by Gaulme et al (2011) claimed a promising detection of trapped oscillations, while Hedman and Nicholson (2013) have shown that trapped waves in Saturn cause detectable perturbations in Saturn's C ring. Both these papers have fueled interest in using seismology as a tool for studying the solar system's giant planets. To fully exploit planetary seismology as a tool for understanding giant planet structure, measurements need to be made from space, however, much can be learned about Jupiter and Saturn using ground-based measurements. We will present the first results from a ground-based observing campaign of Jupiter and Saturn, made from the Bok 90" telescope on Kitt Peak, intended to validate the work of Gaulme et al, and extend such observations to Saturn.

  15. General principles of carotid Doppler ultrasonography

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Whal [Dept. of Radiology, Seoul National University College of Medicine, Seoul (Korea, Republic of)

    2014-03-15

    Carotid Doppler ultrasonography is a popular tool for evaluating atherosclerosis of the carotid artery. Its two-dimensional gray scale can be used for measuring the intima-media thickness, which is very good biomarker for atherosclerosis and can aid in plaque characterization. The plaque morphology is related to the risk of stroke. The ulceration of plaque is also known as one of the strong predictors of future embolic event risk. Color Doppler ultrasonography and pulse Doppler ultrasonography have been used for detecting carotid artery stenosis. Doppler ultrasonography has unique physical properties. The operator should be familiar with the physics and other parameters of Doppler ultrasonography to perform optimal Doppler ultrasonography studies.

  16. Inverse Doppler Effects in Flute

    CERN Document Server

    Zhao, Xiao P; Liu, Song; Shen, Fang L; Li, Lin L; Luo, Chun R

    2015-01-01

    Here we report the observation of the inverse Doppler effects in a flute. It is experimentally verified that, when there is a relative movement between the source and the observer, the inverse Doppler effect could be detected for all seven pitches of a musical scale produced by a flute. Higher tone is associated with a greater shift in frequency. The effect of the inverse frequency shift may provide new insights into why the flute, with its euphonious tone, has been popular for thousands of years in Asia and Europe.

  17. Study of an image-derived SUV and a modified SUV using mouse FDG-PET

    Energy Technology Data Exchange (ETDEWEB)

    Zheng Xiujuan, E-mail: zhengxj@eie.polyu.edu.h [Department of Electronic Information Engineering, the Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong); Yu, Chin-Lung; Sha Wei; Radu, Caius; Huang, Sung-Cheng [Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at UCLA, University of California Los Angeles, CA (United States); Feng Dagan [Department of Electronic Information Engineering, the Hong Kong Polytechnic University, Hung Hom, Kowloon (Hong Kong); School of Information Technologies, the University of Sydney, Sydney (Australia)

    2011-04-15

    Introduction: Standard uptake value (SUV) is calculated without consideration of the differences in plasma 2-deoxy-2-[18F]fluoro-D-glucose (FDG) clearance. Its variability can be affected by changes of the amount of excreted FDG by renal function. Moreover, the estimation of SUV is quite sensitive to errors in the measurements of body weight and injected dose. This study aims to develop an image-based method to obtain an image-derived SUV (iSUV) and a modified SUV (mSUV) to overcome these problems. Methods: Thirty-one tumor-planted SCID mice were scanned in micro-positron emission tomography (PET) at {approx}60 min post FDG injection and then scanned in micro-computed tomographic (CT). Using image-based method, the body weight and injected dose were derived from the microPET/CT images to calculate iSUV. The volumes and the total activities of FDG within the bladder and the whole-body were also obtained to calculate mSUV. For the selected targets, the iSUVs and mSUVs were compared against their corresponding SUVs. Results: Compared with SUV factor (injected dose/body weight), iSUV factor had an average percentage error of -0.7%. The linear regressions between SUV and iSUV had a slope of 0.99 with correlation coefficient of 0.95. Compared with SUV and iSUV, coefficient of variation of mSUV decreased while the tumor-to-background separation of mSUV increased. Conclusions: Using this image-based method, the iSUV can replace SUV when the actual measurements were missing or unreliable. The mSUV can reduce the inter-subject variability and enhance the tumor-to-background separation in mouse FDG-PET studies.

  18. Glioma grade assessment by using histogram analysis of diffusion tensor imaging-derived maps

    International Nuclear Information System (INIS)

    Current endeavors in neuro-oncology include morphological validation of imaging methods by histology, including molecular and immunohistochemical techniques. Diffusion tensor imaging (DTI) is an up-to-date methodology of intracranial diagnostics that has gained importance in studies of neoplasia. Our aim was to assess the feasibility of discriminant analysis applied to histograms of preoperative diffusion tensor imaging-derived images for the prediction of glioma grade validated by histomorphology. Tumors of 40 consecutive patients included 13 grade II astrocytomas, seven oligoastrocytomas, six grade II oligodendrogliomas, three grade III oligoastrocytomas, and 11 glioblastoma multiformes. Preoperative DTI data comprised: unweighted (B0) images, fractional anisotropy, longitudinal and radial diffusivity maps, directionally averaged diffusion-weighted imaging, and trace images. Sampling consisted of generating histograms for gross tumor volumes; 25 histogram bins per scalar map were calculated. The histogram bins that allowed the most precise determination of low-grade (LG) or high-grade (HG) classification were selected by multivariate discriminant analysis. Accuracy of the model was defined by the success rate of the leave-one-out cross-validation. Statistical descriptors of voxel value distribution did not differ between LG and HG tumors and did not allow classification. The histogram model had 88.5% specificity and 85.7% sensitivity in the separation of LG and HG gliomas; specificity was improved when cases with oligodendroglial components were omitted. Constructing histograms of preoperative radiological images over the tumor volume allows representation of the grade and enables discrimination of LG and HG gliomas which has been confirmed by histopathology. (orig.)

  19. Understanding Doppler Broadening of Gamma Rays

    Energy Technology Data Exchange (ETDEWEB)

    Rawool-Sullivan, Mohini [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Sullivan, John P. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-07-03

    Doppler-broadened gamma ray peaks are observed routinely in the collection and analysis of gamma-ray spectra. If not recognized and understood, the appearance of Doppler broadening can complicate the interpretation of a spectrum and the correct identification of the gamma ray-emitting material. We have conducted a study using a simulation code to demonstrate how Doppler broadening arises and provide a real-world example in which Doppler broadening is found. This report describes that study and its results.

  20. Reverse Doppler Effect of Sound

    OpenAIRE

    Lee, Sam Hyeon; Park, Choon Mahn; Seo, Yong Mun; Wang, Zhi Guo; Kim, Chul Koo

    2009-01-01

    We report observation of reverse Doppler effect in a double negative acoustic metamaterial. The metamaterial exhibited negative phase velocity and positive group velocity. The dispersion relation is such that the wavelength corresponding to higher frequency is longer. We observed that the frequency was down-shifted for the approaching source, and up-shifted when the source receded.

  1. Temporal cloak via Doppler broadening

    Science.gov (United States)

    Jabar, M. S. Abdul; Bacha, Bakht Amin; Ahmad, Iftikhar

    2015-06-01

    In this article we propose a new scheme for a temporal cloak based on a five level experimental rubidium or cesium atomic system. In the thought experiment, a cloaking time gap is created between the enhanced subluminal and superluminal pulse caused by Doppler broadening in the medium. A cloaking time in microseconds is attained and no distortion is observed in the pulse.

  2. Anomalous Doppler effects in bulk phononic crystal

    International Nuclear Information System (INIS)

    Doppler effects in simple cubic phononic crystal are studied theoretically and numerically. In addition to observing Doppler shifts from a moving source's frequencies inside the gap, we find that Doppler shifts can be multi-order, anisotropic, and the dominant order of shift depends on the band index that the source's frequency is in.

  3. The Doppler Effect--A New Approach

    Science.gov (United States)

    Allen, J.

    1973-01-01

    Discusses the Doppler effect as it applies to different situations, such as a stationary source of sound with the observer moving, a stationary observer, and the sound source and observer both moving. Police radar, satellite surveillance radar, radar astronomy, and the Doppler navigator, are discussed as applications of Doppler shift. (JR)

  4. Correlation between the Quantifiable Parameters of Whole Solitary Pulmonary Nodules Perfusion Imaging Derived with Dynamic CT and Nodules Size

    Directory of Open Access Journals (Sweden)

    Shiyuan LIU

    2009-05-01

    Full Text Available Background and objective The solitary pulmonary nodules (SPNs is one of the most common findings on chest radiographs. The blood flow patterns of the biggest single SPNs level has been studied. This assessment may be only a limited sample of the entire region of interest (ROI and is unrepresentative of the SPNs as a volume. Ideally, SPNs volume perfusion should be measured. The aim of this study is to evaluate the correlation between the quantifiableparameters of SPNs volume perfusion imaging derived with 16-slice spiral CT and 64-slice spiral CT and nodules size. Methods Sixty-five patients with SPNs (diameter?3 cm; 42 malignant; 12 active inflammatory; 11 benign underwent multi-location dynamic contrast material-enhanced serial CT scanning mode with stable table were performed; The mean values of valid sections were calculated, as the quantifiable parameters of volume SPNs perfusion imaging derived with16-slice spiral CT and 64-slice spiral CT. The correlation between the quantifiable parameters of SPNs volume perfusion imaging derived with 16-slice spiral CT and 64-slice spiral CT and nodules size were assessed by means of linear regression analysis. Results No significant correlations were found between the nodules size and each of the peak height (PHSPN (32.15 Hu±14.55 Hu?ratio of peak height of the SPN to that of the aorta (SPN-to-A ratio(13.20±6.18%, perfusion(PSPN (29.79±19.12 mLmin-1100 g-1 and mean transit time (12.95±6.53 s (r =0.081, P =0.419; r =0.089, P =0.487; r =0.167, P =0.077; r =0.023, P =0.880. Conclusion No significant correlations were found between the quantifiable parameters of SPNs volume perfusion imaging derived with 16-slice spiral CT and 64-slice spiral CT and nodules size.

  5. The micro-doppler effect in radar

    CERN Document Server

    Chen, Victor

    2011-01-01

    This highly practical resource provides you with thorough working knowledge of the micro-Doppler effect in radar, including its principles, applications and implementation with MATLAB codes. The book presents code for simulating radar backscattering from targets with various motions, generating micro-Doppler signatures, and analyzing the characteristics of targets. You find detailed descriptions of the physics and mathematics of the Doppler and micro-Doppler effect. Moreover, you learn how to derive rigid and non-rigid body motion induced micro-Doppler effect in radar scattering. The book prov

  6. Doppler indicates of uterine artery Doppler velocimetry by placental location

    Energy Technology Data Exchange (ETDEWEB)

    Han, Sung Shik; Park, Yong Won; Cho, Jae Sung; Kwon, Hye Kyeung; Kim, Jae Wook [Yonsei University College of Medicine, Seoul (Korea, Republic of)

    2001-09-15

    Our purpose was to investigate the relation between the vascular resistance of uterine artery and placental location and to establish the reference value of Doppler index in uterine artery by placental location. Placental location and flow velocity waveforms of both uterine arteries in 7,016 pregnant women after 18 weeks gestation were examined using color Doppler ultrasonography. Placental location was classified as central and lateral placental and the uterine artery with lateral placental were divided into ipsilateral uterine artery (same side of the placental) and contralateral uterine artery (opposite side of the placenta). The uterine artery with central placental was classified as the central uterine artery. Systolic-Diastolic ratio (S/D ratio) of uterine arteries by gestational weeks were calculated and compared with the placental location and perinatal outcomes. In the lateral placental group, the S/D ratio of the contralateral uterine artery was higher than the ipsilateral one (mean=2.08+0.34 vs 1.89+0.34, p=0.0001). S/D ratio of the uterine artery decreased during second trimester and the ratio after 27 weeks was a tendency to have a constant values(ipsilateral: 1.85+ 0.34, central : 1.96+ 0.40, contralateral: 2.01+0.54). S/D ratio of the uterine artery was affected by placental location. So when we evaluate Doppler spectrum of uterine artery, placental location should be considered and we established the reference value of Doppler index of uterine artery by placental location.

  7. Doppler tomography in fusion plasmas and astrophysics

    DEFF Research Database (Denmark)

    Salewski, Mirko; Geiger, B.; Heidbrink, W. W.; Jacobsen, Asger Schou; Korsholm, Søren Bang; Leipold, Frank; Madsen, Jens; Moseev, D.; Nielsen, Stefan Kragh; Rasmussen, Jesper; Stagner, L.; Steeghs, D.; Stejner Pedersen, Morten; Tardini, G.; Weiland, M.

    2015-01-01

    Doppler tomography is a well-known method in astrophysics to image the accretion flow, often in the shape of thin discs, in compact binary stars. As accretion discs rotate, all emitted line radiation is Doppler-shifted. In fast-ion Dα (FIDA) spectroscopy measurements in magnetically confined plasma......, the Dα-photons are likewise Doppler-shifted ultimately due to gyration of the fast ions. In either case, spectra of Doppler-shifted line emission are sensitive to the velocity distribution of the emitters. Astrophysical Doppler tomography has lead to images of accretion discs of binaries revealing...... bright spots, spiral structures and flow patterns. Fusion plasma Doppler tomography has led to an image of the fast-ion velocity distribution function in the tokamak ASDEX Upgrade. This image matched numerical simulations very well. Here we discuss achievements of the Doppler tomography approach, its...

  8. The Junkyard in the Jungle: Transnational, Transnatural Nature in Karen Tei Yamashita’s Through the Arc of the Rain Forest

    Directory of Open Access Journals (Sweden)

    Begoña Simal

    2010-03-01

    Full Text Available In this new millennium the relatively young field of ecocriticism has had to face important transdisciplinary, transnational, and transnatural challenges. This article attempts to demonstrate how two of the major changes that environmental criticism is currently undergoing, the transnational turn and the transnatural challenge, have both been encoded in Through the Arc of the Rain Forest (1990, the first novel published by Karen Tei Yamashita. I particularly focus on a significant episode in Through the Arc of the Rain Forest, when a peculiar anthropogenic ecosystem is discovered, and interpret it according to Leo Marx’s classic paradigm of “the machine in the garden.” I intend to prove that Yamashita’s novel not only revisits the old master theory but also revamps it by destabilizing the classic human-nature divide inherent in first-wave ecocriticism and by adding the transnational ingredient. Thus, the machine-in-the-garden paradigm is updated in order to incorporate the broadening of current environmental criticism, both literally (globalization and conceptually (transnatural nature. While at times Marx’s paradigm may metamorphose in intriguing ways, the old trope also corroborates its continuing validity. Though filtered by the sieve of globalization and shaken by the emergence of cyborg ecosystems, “the machine in the garden” has survived as a compelling ecocritical framework, even if it occasionally mutates into a junkyard in the jungle.

  9. Measurement of the Doppler power of flowing blood using ultrasound Doppler devices.

    Science.gov (United States)

    Huang, Chih-Chung; Chou, Hung-Lung; Chen, Pay-Yu

    2015-02-01

    Measurement of the Doppler power of signals backscattered from flowing blood (henceforth referred to as the Doppler power of flowing blood) and the echogenicity of flowing blood have been used widely to assess the degree of red blood cell (RBC) aggregation for more than 20 y. Many studies have used Doppler flowmeters based on an analogue circuit design to obtain the Doppler shifts in the signals backscattered from flowing blood; however, some recent studies have mentioned that the analogue Doppler flowmeter exhibits a frequency-response problem whereby the backscattered energy is lost at higher Doppler shift frequencies. Therefore, the measured Doppler power of flowing blood and evaluations of RBC aggregation obtained using an analogue Doppler device may be inaccurate. To overcome this problem, the present study implemented a field-programmable gate array-based digital pulsed-wave Doppler flowmeter to measure the Doppler power of flowing blood, in the aim of providing more accurate assessments of RBC aggregation. A clinical duplex ultrasound imaging system that can acquire pulsed-wave Doppler spectrograms is now available, but its usefulness for estimating the ultrasound scattering properties of blood is still in doubt. Therefore, the echogenicity and Doppler power of flowing blood under the same flow conditions were measured using a laboratory pulser-receiver system and a clinical ultrasound system, respectively, for comparisons. The experiments were carried out using porcine blood under steady laminar flow with both RBC suspensions and whole blood. The experimental results indicated that a clinical ultrasound system used to measure the Doppler spectrograms is not suitable for quantifying Doppler power. However, the Doppler power measured using a digital Doppler flowmeter can reveal the relationship between backscattering signals and the properties of blood cells because the effects of frequency response are eliminated. The measurements of the Doppler power and echogenicity of flowing blood were compared with those obtained in several previous studies. PMID:25542489

  10. Mapping of airborne Doppler radar data

    Energy Technology Data Exchange (ETDEWEB)

    Lee, W.; Dodge, P.; Marks, F.D. Jr.; Hildebrand, P.H. (National Center for Atmospheric Research, Boulder, CO (United States) NOAA, Miami, FL (United States))

    1994-04-01

    Two sets of equations are derived to (1) map airborne Doppler radar data from an aircraft-relative coordinate system to an earth-relative coordinate system, and (2) remove the platform motion from the observed Doppler velocities. These equations can be applied to data collected by the National Oceanic and Atmospheric Administration WP-3D system, the National Center for Atmospheric Research Electra Doppler Radar (ELDORA) system, and other airborne radar systems.

  11. Doppler Resilient Waveforms with Perfect Autocorrelation

    OpenAIRE

    Pezeshki, Ali; Calderbank, A. Robert; Moran, William; Howard, Stephen D.

    2007-01-01

    We describe a method of constructing a sequence of phase coded waveforms with perfect autocorrelation in the presence of Doppler shift. The constituent waveforms are Golay complementary pairs which have perfect autocorrelation at zero Doppler but are sensitive to nonzero Doppler shifts. We extend this construction to multiple dimensions, in particular to radar polarimetry, where the two dimensions are realized by orthogonal polarizations. Here we determine a sequence of two-by-two Alamouti ma...

  12. Doppler principle - inspiration of modern physics

    International Nuclear Information System (INIS)

    The Doppler principle not only represents a useful experimental method of velocity measurement in many fields of science and technology, it is deeply embedded in the foundations of modern relativistic and quantum physics. The discovery of the anomalous Doppler effect exactly 50 years ago and the development of microwave electronics, laser techniques and plasma physics made possible new extensive applications and a deeper understanding of the Doppler principle; this is true especially in the case of supersonic and supraluminous motions. Also, the Einstein quantum theory of radiation has been modified by including new types of quantum transitions closely related to the Doppler effect. (author) 12 refs

  13. Doppler-free two-photon spectroscopy

    International Nuclear Information System (INIS)

    Explains the method of removing the Doppler shift by using two overlapping laser beams in opposite directions. The Doppler shift of the frequency of one beam is cancelled out by that of the other. In spectroscopy this means that the resolution is governed by the natural spectrum line width (MHz) instead of the Doppler width (GHz). The method is used to study spectrum details within the Doppler width: the fine and hyperfine structure, Zeeman effect, Stark effect, isotope shift and effects of interatomic collisions. Some experiments with sodium vapour are described. The method can be extended to n-photon spectroscopy, with n beams at different frequencies. (J.S.)

  14. Intrarenal Doppler: characteristics of aging kidneys.

    Science.gov (United States)

    Terry, J D; Rysavy, J A; Frick, M P

    1992-12-01

    The normal range of Doppler findings in native kidneys has not been studied extensively. This study correlates changes in Doppler resistive index (RI) with age in patients without renal risk factors or renal disease. Young and old patients demonstrated the highest RI values (age 59, RI = 0.68), and patients in the 20-39 year age group showed the lowest values (RI = 0.59). The mean RI for all ages was 0.63. The cause of this variability is unknown. We suggest that age-related changes in Doppler values should be considered in the interpretation of renal Doppler measurements. PMID:1494196

  15. Doppler Imaging of Ap Stars

    CERN Document Server

    Kuschnig, R

    1998-01-01

    Doppler imaging, a technique which inverts spectral line profile variations of an Ap star into a two-dimensional abundance maps, provides new observational constraints on diffusion mechanism in the presence of a global magnetic field. A programme is presented here with the aim to obtain abundance distributions of at least five elements on each star, in order to study how different diffusion processes act under influence of a stellar magnetic field. The importance of this multi-element approach is demonstrated, by presenting the abundance maps of helium, magnesium, silicon, chromium and iron for the magnetic B9pSi star CU Virginis.

  16. Airborne Differential Doppler Weather Radar

    Science.gov (United States)

    Meneghini, R.; Bidwell, S.; Liao, L.; Rincon, R.; Heymsfield, G.; Hildebrand, Peter H. (Technical Monitor)

    2001-01-01

    The Precipitation Radar aboard the Tropical Rain Measuring Mission (TRMM) Satellite has shown the potential for spaceborne sensing of snow and rain by means of an incoherent pulsed radar operating at 13.8 GHz. The primary advantage of radar relative to passive instruments arises from the fact that the radar can image the 3-dimensional structure of storms. As a consequence, the radar data can be used to determine the vertical rain structure, rain type (convective/stratiform) effective storm height, and location of the melting layer. The radar, moreover, can be used to detect snow and improve the estimation of rain rate over land. To move toward spaceborne weather radars that can be deployed routinely as part of an instrument set consisting of passive and active sensors will require the development of less expensive, lighter-weight radars that consume less power. At the same time, the addition of a second frequency and an upgrade to Doppler capability are features that are needed to retrieve information on the characteristics of the drop size distribution, vertical air motion and storm dynamics. One approach to the problem is to use a single broad-band transmitter-receiver and antenna where two narrow-band frequencies are spaced apart by 5% to 10% of the center frequency. Use of Ka-band frequencies (26.5 GHz - 40 GHz) affords two advantages: adequate spatial resolution can be attained with a relatively small antenna and the differential reflectivity and mean Doppler signals are directly related to the median mass diameter of the snow and raindrop size distributions. The differential mean Doppler signal has the additional property that this quantity depends only on that part of the radial speed of the hydrometeors that is drop-size dependent. In principle, the mean and differential mean Doppler from a near-nadir viewing radar can be used to retrieve vertical air motion as well as the total mean radial velocity. In the paper, we present theoretical calculations for the differential reflectivity and Doppler as functions of the center frequency, frequency difference, and median mass diameter. For a fixed pair of frequencies, the detectability of the differential signals can be expressed as the number of independent samples required to detect rain or snow with a particular median mass diameter. Because sampling numbers on the order of 1000 are needed to detect the differential signal over a range of size distributions, the instrument must be confined to a near-nadir, narrow swath. Radar measurements from a zenith directed radar operated at 9.1 GHz and 10 GHz are used to investigate the qualitative characteristics of the differential signals. Disdrometer and rain gauge data taken at the surface, just below the radar, are used to test whether the differential signals can be used to estimate characteristics of the raindrop size distribution.

  17. Doppler tomography in fusion plasmas and astrophysics

    DEFF Research Database (Denmark)

    Salewski, Mirko; Geiger, B.

    2015-01-01

    Doppler tomography is a well-known method in astrophysics to image the accretion flow, often in the shape of thin discs, in compact binary stars. As accretion discs rotate, all emitted line radiation is Doppler-shifted. In fast-ion D? (FIDA) spectroscopy measurements in magnetically confined plasma, the D?-photons are likewise Doppler-shifted ultimately due to gyration of the fast ions. In either case, spectra of Doppler-shifted line emission are sensitive to the velocity distribution of the emitters. Astrophysical Doppler tomography has lead to images of accretion discs of binaries revealing bright spots, spiral structures and flow patterns. Fusion plasma Doppler tomography has led to an image of the fast-ion velocity distribution function in the tokamak ASDEX Upgrade. This image matched numerical simulations very well. Here we discuss achievements of the Doppler tomography approach, its promise and limits, analogies and differences in astrophysical and fusion plasma Doppler tomography and what can be learned by comparison of these applications.

  18. Microwave Doppler radar in unobtrusive health monitoring

    Science.gov (United States)

    Silva Girão, P.; Postolache, O.; Postolache, G.; Ramos, P. M.; Dias Pereira, J. M.

    2015-02-01

    This article frames the use of microwave Doppler radar in the context of ubiquitous, non-obstructive health monitoring. The use of a 24GHz CW (continuous wave) Doppler radar based on a commercial off-the-shelf transceiver for remote sensing of heart rate and respiration rate based on the acquisition and processing of the signals delivered by the radar is briefly presented.

  19. Microwave Doppler radar in unobtrusive health monitoring

    International Nuclear Information System (INIS)

    This article frames the use of microwave Doppler radar in the context of ubiquitous, non-obstructive health monitoring. The use of a 24GHz CW (continuous wave) Doppler radar based on a commercial off-the-shelf transceiver for remote sensing of heart rate and respiration rate based on the acquisition and processing of the signals delivered by the radar is briefly presented

  20. Doppler tomography in fusion plasmas and astrophysics

    International Nuclear Information System (INIS)

    Doppler tomography is a well-known method in astrophysics to image the accretion flow, often in the shape of thin discs, in compact binary stars. As accretion discs rotate, all emitted line radiation is Doppler-shifted. In fast-ion D? (FIDA) spectroscopy measurements in magnetically confined plasma, the D?-photons are likewise Doppler-shifted ultimately due to gyration of the fast ions. In either case, spectra of Doppler-shifted line emission are sensitive to the velocity distribution of the emitters. Astrophysical Doppler tomography has lead to images of accretion discs of binaries revealing bright spots, spiral structures and flow patterns. Fusion plasma Doppler tomography has led to an image of the fast-ion velocity distribution function in the tokamak ASDEX Upgrade. This image matched numerical simulations very well. Here we discuss achievements of the Doppler tomography approach, its promise and limits, analogies and differences in astrophysical and fusion plasma Doppler tomography and what can be learned by comparison of these applications. (paper)

  1. Doppler study of precordial musical murmurs.

    Science.gov (United States)

    Pennestri, F; Boccardi, L; Minardi, G; Di Segni, M; Pucci, E; Biasucci, L M; Ferrari, O; Lombardo, A; Giovannini, E; Loperfido, F

    1989-06-01

    Using phonocardiography, continuous- and pulsed-wave Doppler, 51 patients with precordial "musical" murmurs (49 with cardiac abnormalities) and 21 patients with noisy murmurs were examined. With M-mode echocardiography, fine fluttering of the structure generating the murmur was evident in 23 patients with musical murmurs and in 5 with noisy murmurs. A continuous-wave Doppler spectral signal characterized by parallel harmonics (Doppler musical signal) was evident in all patients with musical murmurs and in none with a noisy murmur. With pulsed-wave Doppler, the musical signal had less defined spectral features because of range ambiguity. Such a signal was experimentally reproduced by activating a diapason bathed in saline solution. The source of the musical murmur was established in all 51 patients by Doppler. The musical signal was associated with a valvular regurgitation signal in 36 patients and with a ventricular septal defect in 1 patient. The musical signal always disappeared when the pulsed-wave Doppler sample volume was placed 2 cm away from the generating structure. In 11 patients with musical murmur examined by color Doppler, no abnormal bidirectional flow signal was observed in the structures generating the signal. In 6 of the patients without valvular regurgitation, no flow disturbance was found. In conclusion, Doppler is valuable in determining the source of musical murmurs, and musical murmurs are caused by a vibrating structure even in the absence of flow turbulence. PMID:2729112

  2. Doppler Resilient Waveforms with Perfect Autocorrelation

    CERN Document Server

    Pezeshki, A; Moran, W; Howard, S D; Pezeshki, Ali; Moran, William; Howard, Stephen D.

    2007-01-01

    We describe a method of constructing a sequence of phase coded waveforms with perfect autocorrelation in the presence of Doppler shift. The constituent waveforms are Golay complementary pairs which have perfect autocorrelation at zero Doppler but are sensitive to nonzero Doppler shifts. We extend this construction to multiple dimensions, in particular to radar polarimetry, where the two dimensions are realized by orthogonal polarizations. Here we determine a sequence of two-by-two Alamouti matrices where the entries involve Golay pairs and for which the sum of the matrix-valued ambiguity functions vanish at small Doppler shifts. The Prouhet-Thue-Morse sequence plays a key role in the construction of Doppler resilient sequences of Golay pairs.

  3. Estimating the Doppler centroid of SAR data

    DEFF Research Database (Denmark)

    Madsen, Søren Nørvang

    1989-01-01

    After reviewing frequency-domain techniques for estimating the Doppler centroid of synthetic-aperture radar (SAR) data, the author describes a time-domain method and highlights its advantages. In particular, a nonlinear time-domain algorithm called the sign-Doppler estimator (SDE) is shown to have...... attractive properties. An evaluation based on an existing SEASAT processor is reported. The time-domain algorithms are shown to be extremely efficient with respect to requirements on calculations and memory, and hence they are well suited to real-time systems where the Doppler estimation is based on raw SAR...... data. For offline processors where the Doppler estimation is performed on processed data, which removes the problem of partial coverage of bright targets, the ΔE estimator and the CDE (correlation Doppler estimator) algorithm give similar performance. However, for nonhomogeneous scenes it is found that...

  4. Color doppler sonography in thickened gallbladder wall

    Energy Technology Data Exchange (ETDEWEB)

    Han, Sang Suk; Choi, Seok Jin; Seo, Chang Hae; Eun, Choong Ki [Inje Univ. College of Medicine, Kimhae (Korea, Republic of)

    1996-11-01

    The thickening of the gallbladder wall is a valuable finding for the diagnosis of cholecystitis, but may be seen in non-cholecystic disease as well as in acute or chronic cholecystitis. The purpose of this study is to determine the value of color Doppler sonography in differentiating the causes of thickened gallbladder wall. Ninety eight patients with thickened gallbladder wall(more than 3mm) which was not due to gallbladder cancer were prospectively evaluated with color Doppler sonography. Sixty-six cases, confirmed by pathologic reports and clinical records, were analyzed for correlation between thickened gallbladder wall and color flow signal according to the underlying causes. Of the 66 patients, 28 cases were cholecystitis and 38 cases had non-cholecystic causes such as liver cirrhosis, ascites, hepatitis, pancreatitis, renal failure, and hypoalbuminemia. Of the 28 patients with cholecystitis(12 acute, 16 chronic), 23(82%) had color Doppler flow signals in the thickened gallbladder wall. Of the 38 patients with non-cholecystic causes, eight(21%) had color Doppler flow signals. There was a statistically significant difference of color Doppler flow signals between the cholecystitis and non-cholecystic groups(p=0.0001). No significant difference of color Doppler flow signals was found between cases of acute and chronic cholecystitis. Of the 23 patients with color Doppler flow signals in 28 cases of cholecystitis, 18(78.3%) showed a linear pattern and five(21.7%) showed a spotty pattern. Of the eight patients with color Doppler flow signals in the 38 non-cholecystic cases, four(50%) showed a linear pattern and four(50%) showed a spotty pattern. In cholecystitis, a linear color Doppler flow signal pattern is a much more frequent finding than a spotty pattern. Color Doppler sonography is a useful and adequate method for determining whether a thickened gallbladder wall is the result of cholecystitis or has non-cholecystic causes.

  5. Color doppler sonography in thickened gallbladder wall

    International Nuclear Information System (INIS)

    The thickening of the gallbladder wall is a valuable finding for the diagnosis of cholecystitis, but may be seen in non-cholecystic disease as well as in acute or chronic cholecystitis. The purpose of this study is to determine the value of color Doppler sonography in differentiating the causes of thickened gallbladder wall. Ninety eight patients with thickened gallbladder wall(more than 3mm) which was not due to gallbladder cancer were prospectively evaluated with color Doppler sonography. Sixty-six cases, confirmed by pathologic reports and clinical records, were analyzed for correlation between thickened gallbladder wall and color flow signal according to the underlying causes. Of the 66 patients, 28 cases were cholecystitis and 38 cases had non-cholecystic causes such as liver cirrhosis, ascites, hepatitis, pancreatitis, renal failure, and hypoalbuminemia. Of the 28 patients with cholecystitis(12 acute, 16 chronic), 23(82%) had color Doppler flow signals in the thickened gallbladder wall. Of the 38 patients with non-cholecystic causes, eight(21%) had color Doppler flow signals. There was a statistically significant difference of color Doppler flow signals between the cholecystitis and non-cholecystic groups(p=0.0001). No significant difference of color Doppler flow signals was found between cases of acute and chronic cholecystitis. Of the 23 patients with color Doppler flow signals in 28 cases of cholecystitis, 18(78.3%) showed a linear pattern and five(21.7%) showed a spotty pattern. Of the eight patients with color Doppler flow signals in the 38 non-cholecystic cases, four(50%) showed a linear pattern and four(50%) showed a spotty pattern. In cholecystitis, a linear color Doppler flow signal pattern is a much more frequent finding than a spotty pattern. Color Doppler sonography is a useful and adequate method for determining whether a thickened gallbladder wall is the result of cholecystitis or has non-cholecystic causes

  6. Color doppler imaging of subclavian steal phenomenon

    International Nuclear Information System (INIS)

    To evaluate the characteristic color doppler imaging of vertebral artery flow in the subclavian steal phenomenon. The study group consisted of eight patients with reversed vertebral artery flow proved by color Doppler imaging. We classified this flow into two groups:(1) complete reversal;(2) partial reversal, as shown by Doppler velocity waveform. Vertebral angiography was performed in six of eight patients;color Doppler imaging and angiographic findings were compared. On color Doppler imaging, all eight cases with reversed vertebral artery flow showed no signal at the proximal subclavian or brachiocephalic artery. We confirmed shunting of six cases by performing angiography from the contralateral vertebral and basilar artery to the ipsilateral vertebral artery. On the Doppler spectrum, six cases showed complete reversal and two partial reversal. On angiography, one partial reversal case showed complete occlusion of the subclavian artery with abundant collateral circulation of muscular branches of the vertebral artery. On color Doppler imaging, a reversed vertebral artery suggests the subclavian steal phenomenon. In particular, partial reversal waveform may reflect collateral circulation

  7. Color doppler imaging of subclavian steal phenomenon

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Nari Ya; Chung, Tae Sub; Kim, Jai Keun [Yonsei Univ. College of Medicine, Seoul (Korea, Republic of)

    1997-03-01

    To evaluate the characteristic color doppler imaging of vertebral artery flow in the subclavian steal phenomenon. The study group consisted of eight patients with reversed vertebral artery flow proved by color Doppler imaging. We classified this flow into two groups:(1) complete reversal;(2) partial reversal, as shown by Doppler velocity waveform. Vertebral angiography was performed in six of eight patients;color Doppler imaging and angiographic findings were compared. On color Doppler imaging, all eight cases with reversed vertebral artery flow showed no signal at the proximal subclavian or brachiocephalic artery. We confirmed shunting of six cases by performing angiography from the contralateral vertebral and basilar artery to the ipsilateral vertebral artery. On the Doppler spectrum, six cases showed complete reversal and two partial reversal. On angiography, one partial reversal case showed complete occlusion of the subclavian artery with abundant collateral circulation of muscular branches of the vertebral artery. On color Doppler imaging, a reversed vertebral artery suggests the subclavian steal phenomenon. In particular, partial reversal waveform may reflect collateral circulation.

  8. Patient-exposure data for doppler ultrasound

    International Nuclear Information System (INIS)

    In recent years ultrasound imaging and Doppler blood flow measurements have become important tools for use in diagnostic medicine. Commercial pulse-echo imaging equipment was first introduced into commerce in 1963. The first commercial continuous wave Doppler unit was introduced to the marketplace in 1966. As equipment improved and applications developed, the industry experienced rapid growth in the 1970s. One of the more recent growth areas in the application of diagnostic ultrasound has been the use of pulsed Doppler equipment for cardiac applications. Prior to 1976, some continuous wave Doppler ultrasound was used for cardiovascular diagnosis. However, only a single manufacturer marketed a pulsed Doppler clinical instrument for cardiac or peripheral vascular diagnosis. Currently, many continuous wave and pulsed Doppler instruments are commercially available for both peripheral vascular and cardiac diagnosis. This chapter (1) briefly reviews current safety guidelines, regulations, and recommendations for diagnostic ultrasound; (2) discusses the patient-exposure intensities associated with Doppler ultrasound medical equipment and compare these levels of exposure with intensities from other medical ultrasound devices; and (3) considers some of the current information as it relates to the safety of diagnostic ultrasound

  9. IIP Update: A Packaged Coherent Doppler Wind Lidar Transceiver. Doppler Aerosol WiNd Lidar (DAWN)

    Science.gov (United States)

    Kavaya, Michael J.; Koch, Grady J.; Yu, Jirong; Trieu, Bo C.; Amzajerdian, Farzin; Singh, Upendra N.; Petros, Mulugeta

    2006-01-01

    The state-of-the-art 2-micron coherent Doppler wind lidar breadboard at NASA/LaRC will be engineered and compactly packaged consistent with future aircraft flights. The packaged transceiver will be integrated into a coherent Doppler wind lidar system test bed at LaRC. Atmospheric wind measurements will be made to validate the packaged technology. This will greatly advance the coherent part of the hybrid Doppler wind lidar solution to the need for global tropospheric wind measurements.

  10. Doppler Imaging of Exoplanets and Brown Dwarfs

    CERN Document Server

    Crossfield, Ian J M

    2014-01-01

    Doppler Imaging produces 2D global maps of rotating objects using high-dispersion spectroscopy. When applied to brown dwarfs and extrasolar planets, this technique can constrain global atmospheric dynamics and/or magnetic effects on these objects in un- precedented detail. I present the first quantitative assessment of the prospects for Doppler Imaging of substellar objects with current facilities and with future giant ground-based telescopes. Observations will have the greatest sensitivity in K band, but the H and L bands will also be useful for these purposes. To assess the number and availability of targets, I also present a compilation of all measurements of photometric variability, rotation period (P), and projected rotational velocity (v sin i) for brown dwarfs and exoplanets. Several bright objects are already accessible to Doppler Imaging with currently available instruments. With the development of giant ground-based telescopes, Doppler Imaging will become feasible for many dozens of brown dwarfs and...

  11. Laser Doppler flowmeter measures gas velocity

    Science.gov (United States)

    Foreman, W.; Huffaker, R. M.

    1966-01-01

    Utilizing the large magnitudes of Doppler shifts obtainable from a CW gas laser, local velocity vectors are measured by using the visible light from the laser. This technique is applicable for the measurement of velocity of any moving surface.

  12. Student Microwave Experiments Involving the Doppler Effect.

    Science.gov (United States)

    Weber, F. Neff; And Others

    1980-01-01

    Described is the use of the Doppler Effect with microwaves in the measurement of the acceleration due to gravity of falling objects. The experiments described add to the repertoire of quantitative student microwave experiments. (Author/DS)

  13. Intensity changes in the Doppler effect

    OpenAIRE

    Johnson, Montgomery H.; Teller, Edward

    1982-01-01

    When a source moves in any direction, the source strength and the frequencies are altered by the Doppler effect. It is shown that the source strength divided by the cube of the frequency is a Lorentz invariant.

  14. Doppler coefficient measurements in Zebra Core 5

    International Nuclear Information System (INIS)

    Measurements using a central hot loop in Zebra Core 5 are described. Results are given for the Doppler coefficients found in a number of assemblies with PuO2 and 16% PuO2/84% depleted UO2 pins, loaded with different combinations of steel, sodium or void pins. The mixed oxide results are in general about 20% more negative than was calculated using the FD2 data set, but agreement is good if the plutonium contributions in the calculations are omitted. The small positive Doppler coefficient calculated for Pu239 was not observed, and two measurements indicated instead a small negative effect. The Doppler effect in the mixed oxide systems was found to vary approximately as 1/T. The results from the empty loop and non-fissile assemblies indicate either a small negative Doppler effect in steel or alternatively the presence of an unexplained expansion effect. (author)

  15. Evaluation of a pulsed ultrasonic Doppler flowmeter

    Science.gov (United States)

    Wells, M. K.

    1973-01-01

    The in vivo application of the pulsed ultrasound Doppler velocity meter (PUDVM) for measuring arterial velocity waveforms is reported. In particular, the performance of the PUDVM is compared with a hot film anemometer of proven accuracy.

  16. High Throughput Direct Detection Doppler Lidar Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Lite Cycles, Inc. (LCI) proposes to develop a direct-detection Doppler lidar (D3L) technology called ELITE that improves the system optical throughput by more than...

  17. Laser Doppler flowmetry in microvascular surgery

    OpenAIRE

    Adrichem, L.N.A. van

    1992-01-01

    In the first part of this thesis, describing clinical and experimental studies, laser Doppler flowmetry is evaluated as diagnostic tool to assess tissue microcirculation after various microvascular operations. The second part concerns the application of laser Doppler flowmetry to investigate and to objectivate the negative effects of cigarette smoking upon the microcirculation under normal circumstances as well as after microvascular operative procedures. Success of plastic ...

  18. Doppler Effect of Mechanical Waves and Light

    OpenAIRE

    Jiacai Nie; Lianxi Ma; Junjun Yang

    2009-01-01

    We discussed the Doppler Effect of mechanical waves when the relative velocity is not in the direction of wave vector;and we found that the observed frequency changes with time, which is different from the results when the relativevelocity is along the wave vector direction. We showed a simple derivation of Doppler Effect equation for the light byusing time dilation principle and showed that the motion of light source and observer has the same effect on thefrequency shift

  19. Doppler spectral characteristics of infrainguinal vein bypasses

    DEFF Research Database (Denmark)

    Nielsen, Tina G; von Jessen, F; Sillesen, H; Schroeder, T V

    1993-01-01

    With the aim of assessing the velocity profile of femoropopliteal and femorocrural vein bypasses, 128 patients undergoing infrainguinal vein bypass surgery entered a postoperative Duplex surveillance protocol, which included clinical assessment and Duplex scanning, using Doppler spectral analysis....... Doppler spectra were obtained at three sites in each graft and the following waveform parameters recorded: maximum systolic velocity, minimum diastolic velocity and resistance index. In patent reconstructions systolic velocity decreased by 30% during the first 6 months after surgery. In the absence of...

  20. Doppler Effect of Mechanical Waves and Light

    Directory of Open Access Journals (Sweden)

    Jiacai Nie

    2009-09-01

    Full Text Available We discussed the Doppler Effect of mechanical waves when the relative velocity is not in the direction of wave vector;and we found that the observed frequency changes with time, which is different from the results when the relativevelocity is along the wave vector direction. We showed a simple derivation of Doppler Effect equation for the light byusing time dilation principle and showed that the motion of light source and observer has the same effect on thefrequency shift

  1. Gapped sampled spectrum Doppler estimation.

    Science.gov (United States)

    Liu, Paul; Liu, Dong

    2013-07-01

    Duplex and triplex transmit patterns that involve gaps in the spectrum Doppler samples allow pulse repetition frequency increases and/or frame rate increases that cannot be flexibly achieved by conventional uniformly sampled transmit schemes. We make two claims in this paper. First, previously reported nonparametric gapped sampled spectrum estimators are technically feasible for handling the duplex and triplex transmit patterns found in common medical ultrasound applications. Second, such estimators that coherently average within an axial/temporal 2-D window have superior SNR compared with their incoherent counterparts. Moreover, this fact extends to previously reported fully sampled incoherent estimators, which can be improved by using their coherent version. We verify the methods by steady-state flow phantom experiments and in vivo examples of the left clavicular artery and the ascending aorta. For the flow phantom experiments, we use the three quantitative metrics of SNR, root mean square error, and zero frequency peak full-width at half-maximum to evaluate robustness and resolution. Results indicate that through proper parameters, periodically gapped estimators can produce results similar to their fully sampled counterparts. Fourier synthesis of the spectral estimates produces the fully sampled time-domain audio signal, and we give stereo audio examples for the clavicular artery. PMID:25004500

  2. Doppler micro sense and avoid radar

    Science.gov (United States)

    Gorwara, Ashok; Molchanov, Pavlo; Asmolova, Olga

    2015-10-01

    There is a need for small Sense and Avoid (SAA) systems for small and micro Unmanned Aerial Systems (UAS) to avoid collisions with obstacles and other aircraft. The proposed SAA systems will give drones the ability to "see" close up and give them the agility to maneuver through tight areas. Doppler radar is proposed for use in this sense and avoid system because in contrast to optical or infrared (IR) systems Doppler can work in more harsh conditions such as at dusk, and in rain and snow. And in contrast to ultrasound based systems, Doppler can better sense small sized obstacles such as wires and it can provide a sensing range from a few inches to several miles. An SAA systems comprised of Doppler radar modules and an array of directional antennas that are distributed around the perimeter of the drone can cover the entire sky. These modules are designed so that they can provide the direction to the obstacle and simultaneously generate an alarm signal if the obstacle enters within the SAA system's adjustable "Protection Border". The alarm signal alerts the drone's autopilot to automatically initiate an avoidance maneuver. A series of Doppler radar modules with different ranges, angles of view and transmitting power have been designed for drones of different sizes and applications. The proposed Doppler radar micro SAA system has simple circuitry, works from a 5 volt source and has low power consumption. It is light weight, inexpensive and it can be used for a variety of small unmanned aircraft.

  3. Neural network processing of FMCW Doppler radar

    Science.gov (United States)

    Fujii, Satoshi

    1994-12-01

    We can obtain ranges and velocities of targets at same time by using a frequency modulated continuous wave (FMCW) Doppler radar. The two-dimensional Fourier transform is conventionally used as the two-dimensional (range and Doppler) spectral analysis on the received signal. The range resolution is determined by the bandwidth over which the FMCW signal is swept. The Doppler resolution is closely equal to the inverse of the coherent integration time (CIT). In this paper, we propose the spectral analysis method for FMCW Doppler radar using a Hopfield neural network, which can yield high-resolution spectra. In this method, the spectral analysis is reformulated as a minimisation problem of difference between the covariance matrixes calculated from observed data and theoretical values. This minimisation problem is mapped on the energy function of the Hopfield neural network and then letting the network converge to the minimum state of that energy function. High-resolution spectra are caused by the non-linear function of neurons and the global connectivity of the network. The performance of this method is evaluated by computer simulations and experimental results. Especially in Doppler resolution, the proposed method is demonstrated to be at least 3-times better than that processed by the conventional two-dimensional Fourier transform method. This high-resolution result contributes to shortening of the CIT and can improve time resolution of the FMCW Doppler radar system.

  4. Estimating the Doppler centroid of SAR data

    DEFF Research Database (Denmark)

    Madsen, SØren NØrvang

    1989-01-01

    After reviewing frequency-domain techniques for estimating the Doppler centroid of synthetic-aperture radar (SAR) data, the author describes a time-domain method and highlights its advantages. In particular, a nonlinear time-domain algorithm called the sign-Doppler estimator (SDE) is shown to have attractive properties. An evaluation based on an existing SEASAT processor is reported. The time-domain algorithms are shown to be extremely efficient with respect to requirements on calculations and memory, and hence they are well suited to real-time systems where the Doppler estimation is based on raw SAR data. For offline processors where the Doppler estimation is performed on processed data, which removes the problem of partial coverage of bright targets, the ?E estimator and the CDE (correlation Doppler estimator) algorithm give similar performance. However, for nonhomogeneous scenes it is found that the nonlinear SDE algorithm, which estimates the Doppler-shift on the basis of data signs alone, gives superior performance

  5. Highly sensitive image-derived indices of water-stressed plants using hyperspectral imaging in SWIR and histogram analysis

    Science.gov (United States)

    Kim, David M.; Zhang, Hairong; Zhou, Haiying; Du, Tommy; Wu, Qian; Mockler, Todd C.; Berezin, Mikhail Y.

    2015-11-01

    The optical signature of leaves is an important monitoring and predictive parameter for a variety of biotic and abiotic stresses, including drought. Such signatures derived from spectroscopic measurements provide vegetation indices – a quantitative method for assessing plant health. However, the commonly used metrics suffer from low sensitivity. Relatively small changes in water content in moderately stressed plants demand high-contrast imaging to distinguish affected plants. We present a new approach in deriving sensitive indices using hyperspectral imaging in a short-wave infrared range from 800 nm to 1600 nm. Our method, based on high spectral resolution (1.56 nm) instrumentation and image processing algorithms (quantitative histogram analysis), enables us to distinguish a moderate water stress equivalent of 20% relative water content (RWC). The identified image-derived indices 15XX nm/14XX nm (i.e. 1529 nm/1416 nm) were superior to common vegetation indices, such as WBI, MSI, and NDWI, with significantly better sensitivity, enabling early diagnostics of plant health.

  6. Doppler measurements of 238U

    International Nuclear Information System (INIS)

    Using filtered beams of neutrons from MURR at three energies (2, 24 and 144 keV), which span the energy range in which the Doppler effect of 238U is most sensitive, average transmission measurements were made for 238U metal, 238U3O8, 238UO2 and 238UC to investigate the thickness and temperature dependence of the EATCS (Effective Average Total Cross Section) of 238U. To study the self shielding effect of 238U metal, U3O8, UO2 and UC at room temperature, measurements were made for different sample thicknesses at all three energies. The selfshielding effect was larger for strongly-bonded materials (U3O8 and UO2) which have sharper resonances. EATCS were measured at 2 keV as a function of temperature between 300 K and 1295 K for 238U in U3O8, UO2 and UC. Temperature-related density effects were suppressed by measuring simultaneously the gamma-rays passing through the sample. The EATCS of 238U metal (a weakly-bonded solid) as a function of temperature was larger than the increase in the EATCS of 238U in U3O8, UO2 and UC (strongly-bonded solids). A stepwise increase was obtained in the EATCS of 238U metal at the melting point. This step is attributed to changes in the crystalling binding of 238U metal, which are directly related to the sudden change in the thermal motion of the 238U atoms. Measured values were compared with the empirical model, which employs the method of stochastically generating a set of pseudo resonance parameters from the initial resonance input parameters for both s-waves and p-waves

  7. Calibrated image-derived input functions for the determination of the metabolic uptake rate of glucose with [18F]-FDG PET

    DEFF Research Database (Denmark)

    Christensen, Anders Nymark; Reichkendler, Michala H.; Larsen, Rasmus; Auerbach, Pernille; Højgaard, Liselotte; Nielsen, Henning B.; Ploug, Thorkil; Stallknecht, Bente; Holm, Søren

    2014-01-01

    We investigated the use of a simple calibration method to remove bias in previously proposed approaches to image-derived input functions (IDIFs) when used to calculate the metabolic uptake rate of glucose (Km) from dynamic [18F]-FDG PET scans of the thigh. Our objective was to obtain nonbiased, low...

  8. Calibrated image-derived input functions for the determination of the metabolic uptake rate of glucose with [18F]-FDG PET

    DEFF Research Database (Denmark)

    Christensen, Anders Nymark; Reichkendler, Michala H.

    2014-01-01

    We investigated the use of a simple calibration method to remove bias in previously proposed approaches to image-derived input functions (IDIFs) when used to calculate the metabolic uptake rate of glucose (Km) from dynamic [18F]-FDG PET scans of the thigh. Our objective was to obtain nonbiased, low-variance Km values without blood sampling.

  9. Ultrasonography with color Doppler and power Doppler in the diagnosis of periapical lesions

    Directory of Open Access Journals (Sweden)

    Sumit Goel

    2011-01-01

    Full Text Available Aim: To evaluate the efficacy of ultrasonography (USG with color Doppler and power Doppler applications over conventional radiography in the diagnosis of periapical lesions. Materials and Methods: Thirty patients having inflammatory periapical lesions of the maxillary or mandibular anterior teeth and requiring endodontic surgery were selected for inclusion in this study. All patients consented to participate in the study. We used conventional periapical radiographs as well as USG with color Doppler and power Doppler for the diagnosis of these lesions. Their diagnostic performances were compared against histopathologic examination. All data were compared and statistically analyzed. Results: USG examination with color Doppler and power Doppler identified 29 (19 cysts and 10 granulomas of 30 periapical lesions accurately, with a sensitivity of 100% for cysts and 90.91% for granulomas and a specificity of 90.91% for cysts and 100% for granulomas. In comparison, conventional intraoral radiography identified only 21 lesions (sensitivity of 78.9% for cysts and 45.4% for granulomas and specificity of 45.4% for cysts and 78.9% for granulomas. There was definite correlation between the echotexture of the lesions and the histopathological features except in one case. Conclusions: USG imaging with color Doppler and power Doppler is superior to conventional intraoral radiographic methods for diagnosing the nature of periapical lesions in the anterior jaws. This study reveals the potential of USG examination in the study of other jaw lesions.

  10. Doppler-guided retrograde catheterization system

    Science.gov (United States)

    Frazin, Leon J.; Vonesh, Michael J.; Chandran, Krishnan B.; Khasho, Fouad; Lanza, George M.; Talano, James V.; McPherson, David D.

    1991-05-01

    The purpose of this study was to investigate a Doppler guided catheterization system as an adjunctive or alternative methodology to overcome the disadvantages of left heart catheterization and angiography. These disadvantages include the biological effects of radiation and the toxic and volume effects of iodine contrast. Doppler retrograde guidance uses a 20 MHz circular pulsed Doppler crystal incorporated into the tip of a triple lumen multipurpose catheter and is advanced retrogradely using the directional flow information provided by the Doppler waveform. The velocity detection limits are either 1 m/second or 4 m/second depending upon the instrumentation. In a physiologic flow model of the human aortic arch, multiple data points revealed a positive wave form when flow was traveling toward the catheter tip indicating proper alignment for retrograde advancement. There was a negative wave form when flow was traveling away from the catheter tip if the catheter was in a branch or bent upon itself indicating improper catheter tip position for retrograde advancement. In a series of six dogs, the catheter was able to be accurately advanced from the femoral artery to the left ventricular chamber under Doppler signal guidance without the use of x-ray. The potential applications of a Doppler guided retrograde catheterization system include decreasing time requirements and allowing safer catheter guidance in patients with atherosclerotic vascular disease and suspected aortic dissection. The Doppler system may allow left ventricular pressure monitoring in the intensive care unit without the need for x-ray and it may allow left sided contrast echocardiography. With pulse velocity detection limits of 4 m/second, this system may allow catheter direction and passage into the aortic root and left ventricle in patients with aortic stenosis. A modification of the Doppler catheter may include transponder technology which would allow precise catheter tip localization once the catheter tip is placed in the aortic root. Such technology may conceivably assist in allowing selective coronary catheterization. These studies have demonstrated that Doppler guided retrograde catheterization provides an accurate method to catheterization the aortic root and left ventricular chamber without x-ray. In humans, it may prove useful in a variety of settings including the development of invasive ultrasonic diagnostic and therapeutic technology.

  11. Doppler radar imaging of spherical planetary surfaces

    International Nuclear Information System (INIS)

    A new approach to making radar reflectivity images of spherical planetary objects uses echo spectra acquired as a function of rotational phase and at an arbitrary number of subradar latitudes. If only equatorial views are used then the image will have a north-south ambiguity. If non-equatorial views are used than unambiguous images are possible. The technique is tailored for depolarized or diffuse (nonspecular) polarized backscatter and works best when the limb darkening is minimal. In developing the Doppler-radar imaging system, the target's reflectivity distribution is expanded in a truncated spherical harmonic series and the distribution of echo power in rotational phase and Doppler frequency is obtained as a linear, analytic function of the series coefficients. To estimate the coefficients from an observed phase-Doppler distribution, the inversion is cast as a least-squares problem and solved using singular value decomposition. The result is a linear imaging system whose capabilities and sensitivity to such factors as subradar latitude coverage and signal-to-noise ratio are easily explored with simulations. Doppler-radar imaging can be used with existing radar telescopes to map the diffuse component of echoes from the inner planets and to make north-south ambiguous reflectivity maps of the icy Galilean satellites. SNRs needed for Doppler-radar imaging of the largest asteroids, Io, and Titan would be accessible upon implementation of upgrades proposed for the Arecibo telescope

  12. Doppler radar imaging of spherical planetary surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Hudson, R.S.; Ostro, S.J. (California Institute of Technology, Pasadena (USA))

    1990-07-10

    A new approach to making radar reflectivity images of spherical planetary objects uses echo spectra acquired as a function of rotational phase and at an arbitrary number of subradar latitudes. If only equatorial views are used then the image will have a north-south ambiguity. If non-equatorial views are used than unambiguous images are possible. The technique is tailored for depolarized or diffuse (nonspecular) polarized backscatter and works best when the limb darkening is minimal. In developing the Doppler-radar imaging system, the target's reflectivity distribution is expanded in a truncated spherical harmonic series and the distribution of echo power in rotational phase and Doppler frequency is obtained as a linear, analytic function of the series coefficients. To estimate the coefficients from an observed phase-Doppler distribution, the inversion is cast as a least-squares problem and solved using singular value decomposition. The result is a linear imaging system whose capabilities and sensitivity to such factors as subradar latitude coverage and signal-to-noise ratio are easily explored with simulations. Doppler-radar imaging can be used with existing radar telescopes to map the diffuse component of echoes from the inner planets and to make north-south ambiguous reflectivity maps of the icy Galilean satellites. SNRs needed for Doppler-radar imaging of the largest asteroids, Io, and Titan would be accessible upon implementation of upgrades proposed for the Arecibo telescope.

  13. The EVE Doppler Sensitivity and Flare Observations

    Science.gov (United States)

    Hudson, H. S.; Woods, T. N.; Chamberlin, P. C.; Didkovsky, L.; Del Zanna, G.

    2011-01-01

    The Extreme-ultraviolet Variability Experiment (EVE) obtains continuous EUV spectra of the Sun viewed as a star. Its primary objective is the characterization of solar spectral irradiance, but its sensitivity and stability make it extremely interesting for observations of variability on time scales down to the limit imposed by its basic 10 s sample interval. In this paper we characterize the Doppler sensitivity of the EVE data. We find that the 30.4 nm line of He II has a random Doppler error below 0.001 nm (1 pm, better than 10 km/s as a redshift), with ample stability to detect the orbital motion of its satellite, the Solar Dynamics Observatory (SDO). Solar flares also displace the spectrum, both because of Doppler shifts and because of EVE's optical layout, which (as with a slitless spectrograph) confuses position and wavelength. As a flare develops, the centroid of the line displays variations that reflect Doppler shifts and therefore flare dynamics. For the impulsive phase of the flare SOL2010-06-12, we find the line centroid to have a redshift of 16.8 +/- 5.9 km/s relative to that of the flare gradual phase (statistical errors only). We find also that high-temperature lines, such as Fe XXIV 19.2 nm, have well-determined Doppler components for major flares, with decreasing apparent blueshifts as expected from chromospheric evaporation flows.

  14. Development of the doppler electron velocimeter: theory.

    Energy Technology Data Exchange (ETDEWEB)

    Reu, Phillip L.

    2007-03-01

    Measurement of dynamic events at the nano-scale is currently impossible. This paper presents the theoretical underpinnings of a method for making these measurements using electron microscopes. Building on the work of Moellenstedt and Lichte who demonstrated Doppler shifting of an electron beam with a moving electron mirror, further work is proposed to perfect and utilize this concept in dynamic measurements. Specifically, using the concept of ''fringe-counting'' with the current principles of transmission electron holography, an extension of these methods to dynamic measurements is proposed. A presentation of the theory of Doppler electron wave shifting is given, starting from the development of the de Broglie wave, up through the equations describing interference effects and Doppler shifting in electron waves. A mathematical demonstration that Doppler shifting is identical to the conceptually easier to understand idea of counting moving fringes is given by analogy to optical interferometry. Finally, potential developmental experiments and uses of a Doppler electron microscope are discussed.

  15. Noninvasive image derived heart input function for CMRglc measurements in small animal slow infusion FDG PET studies

    Science.gov (United States)

    Xiong, Guoming; Cumming, Paul; Todica, Andrei; Hacker, Marcus; Bartenstein, Peter; Böning, Guido

    2012-12-01

    Absolute quantitation of the cerebral metabolic rate for glucose (CMRglc) can be obtained in positron emission tomography (PET) studies when serial measurements of the arterial [18F]-fluoro-deoxyglucose (FDG) input are available. Since this is not always practical in PET studies of rodents, there has been considerable interest in defining an image-derived input function (IDIF) by placing a volume of interest (VOI) within the left ventricle of the heart. However, spill-in arising from trapping of FDG in the myocardium often leads to progressive contamination of the IDIF, which propagates to underestimation of the magnitude of CMRglc. We therefore developed a novel, non-invasive method for correcting the IDIF without scaling to a blood sample. To this end, we first obtained serial arterial samples and dynamic FDG-PET data of the head and heart in a group of eight anaesthetized rats. We fitted a bi-exponential function to the serial measurements of the IDIF, and then used the linear graphical Gjedde-Patlak method to describe the accumulation in myocardium. We next estimated the magnitude of myocardial spill-in reaching the left ventricle VOI by assuming a Gaussian point-spread function, and corrected the measured IDIF for this estimated spill-in. Finally, we calculated parametric maps of CMRglc using the corrected IDIF, and for the sake of comparison, relative to serial blood sampling from the femoral artery. The uncorrected IDIF resulted in 20% underestimation of the magnitude of CMRglc relative to the gold standard arterial input method. However, there was no bias with the corrected IDIF, which was robust to the variable extent of myocardial tracer uptake, such that there was a very high correlation between individual CMRglc measurements using the corrected IDIF with gold-standard arterial input results. Based on simulation, we furthermore find that electrocardiogram-gating, i.e. ECG-gating is not necessary for IDIF quantitation using our approach.

  16. Noninvasive image derived heart input function for CMRglc measurements in small animal slow infusion FDG PET studies.

    Science.gov (United States)

    Xiong, Guoming; Paul, Cumming; Todica, Andrei; Hacker, Marcus; Bartenstein, Peter; Böning, Guido

    2012-12-01

    Absolute quantitation of the cerebral metabolic rate for glucose (CMRglc) can be obtained in positron emission tomography (PET) studies when serial measurements of the arterial [(18)F]-fluoro-deoxyglucose (FDG) input are available. Since this is not always practical in PET studies of rodents, there has been considerable interest in defining an image-derived input function (IDIF) by placing a volume of interest (VOI) within the left ventricle of the heart. However, spill-in arising from trapping of FDG in the myocardium often leads to progressive contamination of the IDIF, which propagates to underestimation of the magnitude of CMRglc. We therefore developed a novel, non-invasive method for correcting the IDIF without scaling to a blood sample. To this end, we first obtained serial arterial samples and dynamic FDG-PET data of the head and heart in a group of eight anaesthetized rats. We fitted a bi-exponential function to the serial measurements of the IDIF, and then used the linear graphical Gjedde-Patlak method to describe the accumulation in myocardium. We next estimated the magnitude of myocardial spill-in reaching the left ventricle VOI by assuming a Gaussian point-spread function, and corrected the measured IDIF for this estimated spill-in. Finally, we calculated parametric maps of CMRglc using the corrected IDIF, and for the sake of comparison, relative to serial blood sampling from the femoral artery. The uncorrected IDIF resulted in 20% underestimation of the magnitude of CMRglc relative to the gold standard arterial input method. However, there was no bias with the corrected IDIF, which was robust to the variable extent of myocardial tracer uptake, such that there was a very high correlation between individual CMRglc measurements using the corrected IDIF with gold-standard arterial input results. Based on simulation, we furthermore find that electrocardiogram-gating, i.e. ECG-gating is not necessary for IDIF quantitation using our approach. PMID:23160517

  17. Analysis of Doppler lidar wind measurements

    Science.gov (United States)

    Srivastava, R. C.

    1986-01-01

    Doppler lidar and multiple Doppler radar data were obtained in a convectively mixed planetary boundary layer. The lidar measurements were possible due to scattering from existing aerosols; radar reflecting chaff was released in the atmosphere to make it visible to the multiple Doppler radar network. The data were analyzed to obtain detailed horizontal wind structures. The divergence of the horizontal wind was calculated and the anelastic continuity equation integrated to obtain vertical air motions. Differences between the areally averaged quantities and the grid point values provided a measure of the fluctuations in the wind components or the turbulent wind fluctuations. Vertical profiles of the mean winds and quantities related to the turbulent kinetic energy components and the turbulent momentum transfers were also calculated.

  18. Diabetic Nephropathy : Evaluation with Doppler Ultrasonography

    Energy Technology Data Exchange (ETDEWEB)

    Sim, Jung Suk; Kim, Seung Hyup; Kang, Heung Sik; Park, Jae Hyung; Han, Man Chung [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    1996-06-15

    To compare Doppler ultrasonography with laboratory tests in evaluation of diabetic nephropathy. Fifty-five patients (mean age = 60, M : F = 26 : 29) with diabetes mellitus underwent renal Doppler ultrasonography. Resistive indices were compared with degree of proteinuria, serum creatinine level, and creatinine clearance rate. Eighteen patients who showed no proteinuria or microscopic proteinuria had a mean resistive index (RI) of 0.72 (SD, 0.05), 16 patients with macroscopic proteinuria without nephrotic syndrome had a mean RI of 0.82 (SD, 0.13), and 21 patients with nephrotic syndrome had a mean RI of 0.90 (SD, 0.12). Renal RI correlated highly with serum creatinine level (r = 0.62) and creatinine clearance rate (r = -0.43). Renal Doppler ultrasonography provides a useful indication of renal function in diabetic nephropathy but cannot offer an advantage over conventional laboratory test

  19. Research on the Laser Doppler Torque Sensor

    International Nuclear Information System (INIS)

    Based on laser Doppler effect, single section rotational speed of a rotating shaft was measured. By measuring the two sections rotational speed, the difference of the rotational speed between the two could be made. Integrating the rotational speed difference, the relative torsional angle of the two sections under the action of torsional virbration was received, so the rotating shaft torque was gotten. Non-contact torque measurement of rotary machine was achieved. The system was designed and the experiment was done on the torque experiment equipment. The result of experimentation indicate that the relative error between Laser Doppler and conventional torque measuring method that was less than 0.2%, and the measurement accuracy of Laser Doppler was high

  20. Diabetic Nephropathy : Evaluation with Doppler Ultrasonography

    International Nuclear Information System (INIS)

    To compare Doppler ultrasonography with laboratory tests in evaluation of diabetic nephropathy. Fifty-five patients (mean age = 60, M : F = 26 : 29) with diabetes mellitus underwent renal Doppler ultrasonography. Resistive indices were compared with degree of proteinuria, serum creatinine level, and creatinine clearance rate. Eighteen patients who showed no proteinuria or microscopic proteinuria had a mean resistive index (RI) of 0.72 (SD, 0.05), 16 patients with macroscopic proteinuria without nephrotic syndrome had a mean RI of 0.82 (SD, 0.13), and 21 patients with nephrotic syndrome had a mean RI of 0.90 (SD, 0.12). Renal RI correlated highly with serum creatinine level (r = 0.62) and creatinine clearance rate (r = -0.43). Renal Doppler ultrasonography provides a useful indication of renal function in diabetic nephropathy but cannot offer an advantage over conventional laboratory test

  1. Arm locking with Doppler estimation errors

    International Nuclear Information System (INIS)

    At the University of Florida we developed the University of Florida LISA Interferometer Simulator (UFLIS) in order to study LISA interferometry with hardware in the loop at a system level. One of the proposed laser frequency stabilization techniques in LISA is arm locking. Arm locking uses an adequately filtered linear combination of the LISA arm signals as a frequency reference. We will report about experiments in which we demonstrated arm locking using UFLIS. During these experiments we also discovered a problem associated with the Doppler shift of the return beam. The initial arm locking publications assumed that this Doppler shift can perfectly be subtracted inside the phasemeter or adds an insignificant offset to the sensor signal. However, the remaining Doppler knowledge error will cause a constant change in the laser frequency if unaccounted for. Several ways to circumvent this problem have been identified. We performed detailed simulations and started preliminary experiments to verify the performance of the proposed new controller designs.

  2. Burst Format Design for Optimum Joint Estimation of Doppler-Shift and Doppler-Rate in Packet Satellite Communications

    OpenAIRE

    Luca Giugno; Francesca Zanier; Marco Luise

    2007-01-01

    This paper considers the problem of optimizing the burst format of packet transmission to perform enhanced-accuracy estimation of Doppler-shift and Doppler-rate of the carrier of the received signal, due to relative motion between the transmitter and the receiver. Two novel burst formats that minimize the Doppler-shift and the Doppler-rate Cramér-Rao bounds (CRBs) for the joint estimation of carrier phase/Doppler-shift and of the Doppler-rate are derived, and a data-aided (DA) estimatio...

  3. Evaluation of a simplified Doppler frequency shifter

    Science.gov (United States)

    Marr, R. A.; Lammers, U. H. W.

    1990-09-01

    Mechanical Doppler frequency shifting of a millimeter or submillimeter wave signal provides a means to implement a sensitive and highly coherent heterodyne receiver in a laboratory system. The rotary shifter which was described by Lammers et al. (1990), is a precision-machined device suitable for use down to submillimeter wavelengths. It was found at 140 GHz, however, that the coherence of such a system is not affected by mechanical imprecision of the frequency shifter, and that the system dynamic range is only moderately affected by mechanical imprecision and by certain design simplifications. Several versions of simpler and less precise Doppler frequency shifters were built. Their performance at 140 GHz is described.

  4. Long-range, noncoherent laser Doppler velocimeter.

    Science.gov (United States)

    Bloom, S H; Kremer, R; Searcy, P A; Rivers, M; Menders, J; Korevaar, E

    1991-11-15

    An experimental demonstration of a long-range, noncoherent laser Doppler velocimeter (LDV) is presented. The LDV detects incoming Doppler-shifted signal photons by using the sharp spectral absorption features in atomic or molecular vapors. The edge of the absorption feature is used to convert changes in frequency to large changes in transmission. Preliminary measurements of wind velocity using seeded aerosols showed that the LDV results agreed with mechanical anemometer measurements to within the accuracy of the LDV measurements. With optimization the LDV will provide accurate range-resolved and vibration-tolerant wind-speed measurements at large distances. PMID:19784143

  5. A visual demo of the Doppler effect

    Science.gov (United States)

    Papacosta, Pangratios

    2010-09-01

    Most physics teachers are familiar with the standard classroom demonstration of the Doppler effect. We invite students to explain the periodic variation of the pitch produced when we swirl a sounding buzzer over our heads. Students are quick to connect this phenomenon to everyday life experiences such as listening to the sound of the siren of a fast-approaching police car or the bell of an approaching train. In addition to these aural experiences, our understanding of the Doppler effect can be strengthened with a useful visual metaphor.

  6. Transcranial Doppler velocimetry in aneurysmal subarachnoid haemorrhage

    DEFF Research Database (Denmark)

    Staalsø, J M; Edsen, T; Romner, B; Olsen, Niels Vidiendal

    2013-01-01

    BACKGROUND: /st>Transcranial Doppler measurements of the middle cerebral artery flow velocity are widely used as an indicator of vasospasm after aneurysmal subarachnoid haemorrhage (SAH). We investigated inter- and intraoperator agreement in SAH patients and healthy volunteers using colour......-coded transcranial Doppler (TCCD), with the secondary aim of describing prediction of angiographic vasospasm and mortality. METHODS: /st>Sixty patients and 70 healthy controls were each examined in duplicate by alternating operators. A total of 939 measurements divided on 201 examination sets were conducted by four...

  7. Doppler-ultralydundersøgelse af underekstremitetsarteriosklerose

    DEFF Research Database (Denmark)

    Rørdam, P; von Jessen, F; Sillesen, H H; Schroeder, T V

    1992-01-01

    Arteriography, which requires resources and is not entirely without risk, has hitherto been a prerequisite for reconstructive surgery in cases of symptom-producing arteriosclerosis in the lower limbs. As an alternative, indirect Doppler ultrasonic examination has been employed but does not appear...... to be suitable in the clinical routine. On the basis of a review of the literature, it is suggested that, employing a combination of ultrasonic picture scanning and Doppler ultrasonic duplex scanning, it may be possible to diagnose significant solitary stenoses or short occlusions in the aorto...

  8. Wind field measurements using doppler radar systems; Messungen von Windfeldern mit Doppler-Radaranlagen

    Energy Technology Data Exchange (ETDEWEB)

    Gekat, F.; Hannesen, R.; Kadner, G.; Kammer, A. [Gematronik GmbH, Neuss (Germany)

    2002-07-01

    The function of a doppler radar system and its application in wind field mesurement is described. Evaluation methods are presented, and the example of an oil well fire is discussed as a practical application. [German] In dieser Arbeit wird die Funktionsweise eines Doppler-Radargeraetes beschrieben, wobei der Schwerpunkt auf die Messung von Windgeschwindigkeiten gelegt wird. Die wichtigsten Auswertungsmethoden zur Ermittlung des Windfeldes mit einem einzelnen Geraet werden vorgestellt. Als Beispiel fuer den Einsatz eines Doppler-Radargeraetes in einer Katastrophensituation werden einige Bilder der Beobachtung einer brennenden Oelbohrstelle gezeigt. (orig.)

  9. TCSP ER-2 DOPPLER RADAR (EDOP) V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The EDOP provides vertically profiled reflectivity and Doppler velocity at aircraft nadir along the flight track. The ER-2 Doppler radar (EDOP) is an X-band (9.6...

  10. TCSP ER-2 DOPPLER RADAR (EDOP) V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The EDOP provides vertically profiled reflectivity and Doppler velocity at aircraft nadir along the flight track. The ER-2 Doppler radar (EDOP) is an X-band (9.6...

  11. Fish embryo multimodal imaging by laser Doppler digital holography

    CERN Document Server

    Verrier, Nicolas; Picart, Pascal; Gross, Michel

    2015-01-01

    A laser Doppler imaging scheme combined to an upright microscope is proposed. Quantitative Doppler imaging in both velocity norm and direction, as well as amplitude contrast of either zebrafish flesh or vasculature is demonstrated.

  12. Operational Bright-Band Snow Level Detection Using Doppler Radar

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A method to detect the bright-band snow level from radar reflectivity and Doppler vertical velocity data collection with an atmospheric profiling Doppler radar. The...

  13. 21 CFR 892.1550 - Ultrasonic pulsed doppler imaging system.

    Science.gov (United States)

    2010-04-01

    21 Food and Drugs 8 ...2010-04-01 false Ultrasonic pulsed doppler imaging system. 892...Section 892.1550 Food and Drugs FOOD AND DRUG ADMINISTRATION... § 892.1550 Ultrasonic pulsed doppler imaging system....

  14. Acoustic micro-Doppler radar for human gait imaging.

    Science.gov (United States)

    Zhang, Zhaonian; Pouliquen, Philippe O; Waxman, Allen; Andreou, Andreas G

    2007-03-01

    A portable acoustic micro-Doppler radar system for the acquisition of human gait signatures in indoor and outdoor environments is reported. Signals from an accelerometer attached to the leg support the identification of the components in the measured micro-Doppler signature. The acoustic micro-Doppler system described in this paper is simpler and offers advantages over the widely used electromagnetic wave micro-Doppler radars. PMID:17407918

  15. Rotational Doppler effect in left-handed materials

    OpenAIRE

    Luo, Hailu; Wen, Shuangchun; Shu, Weixing; Tang, Zhixiang; Zou, Yanhong; Fan, Dianyuan

    2008-01-01

    We explain the rotational Doppler effect associated with light beams carrying with orbital angular momentum in left-handed materials (LHMs). We demonstrate that the rotational Doppler effect in LHMs is unreversed, which is significantly different from the linear Doppler effect. The physics underlying this intriguing effect is the combined contributions of negative phase velocity and inverse screw of wave-front. In the normal dispersion region, the rotational Doppler effect i...

  16. Ultrasonic Doppler color in glaucoma: Concordance study

    International Nuclear Information System (INIS)

    Our study demonstrates that US color Doppler is a non invasive, reliable and reproducible method for the evaluation of the orbitary flow in normal and glaucomatous patients. However is suggested that every group evaluates the inter and intraobserver variability because of the lack of universal reference velocity measurements

  17. Measurements of the Doppler effect at Phenix

    International Nuclear Information System (INIS)

    A measurement of the Doppler effect has been performed at Phenix. Large corrections were necessary. Thus the measurement has been done again on another way. Results agree. A comparison has been made with the results of a theoretical calculation performed with the CARNAVAL IV ''formulaire''

  18. HF Doppler Radar Observations of Geomagnetic Pulsations.

    Czech Academy of Sciences Publication Activity Database

    Fišer, Ji?í; Chum, Jaroslav

    Prague : Matfyzpress, 2014, s. 304-309. ISBN 978-80-7378-276-4. [Week of Doctoral Students /23./ : focused on physical study branches. Prague (CZ), 03.06.2014-05.06.2014] R&D Projects: GA ?R(CZ) GAP209/12/2440 Institutional support: RVO:68378289 Keywords : Doppler sounding * ionosphere * geomagnetic pulsations Subject RIV: DG - Athmosphere Sciences, Meteorology

  19. The Doppler effect measurement on 238U

    International Nuclear Information System (INIS)

    The UO2 sample was irradiated in the RB zero power reactor in order to determine the Doppler effect on the 238 U by measuring the change in the 238 capture cross section with temperature. The measurement was meant to verify the indigenous developed computer codes and nuclear data library

  20. Method for Canceling Ionospheric Doppler Effect

    Science.gov (United States)

    Vessot, R. F. C.

    1982-01-01

    Unified transponder system with hydrogen-maser oscillators at both stations can compensate for both motional and ionospheric components of Doppler shift. Appropriate choices of frequency shift in output of mixer m3. System exploits proportionality between dispersive component of frequency shift and reciprocal of frequency to achieve cancellation of dispersive component at output.

  1. Spectroscopic observation of the rotational Doppler effect

    OpenAIRE

    Barreiro, S.; Tabosa, J. W. R.; Failache, H.; Lezama, A.

    2006-01-01

    We report on the first spectroscopic observation of the rotational Doppler shift associated with light beams carrying orbital angular momentum. The effect is evidenced as the broadening of a Hanle/EIT coherence resonance on Rb vapor when the two incident Laguerre-Gaussian laser beams have opposite topological charges. The observations closely agree with theoretical predictions.

  2. Rubidium Atomic Line Filtered (RALF) Doppler Velocimetry

    Science.gov (United States)

    Fajardo, Mario; Molek, Christopher; Vesely, Annamaria

    2015-06-01

    We report the successful proof-of-concept demonstration of the Rubidium Atomic Line Filtered (RALF) Doppler velocimetry technique. RALF is a high-velocity and high-acceleration adaptation of the Global Doppler Velocimetry (GDV) method developed in the 1990s by aerodynamics researchers. Laser velocimetry techniques in common use within the shock physics community (e . g . VISAR, Fabry-Perot, PDV) decode the Doppler shift of light reflected from a moving surface via interference phenomena. In contrast, RALF employs a completely different physical principle: the frequency-dependent near-resonant optical transmission of a Rb/N2 gas cell, to convert the Doppler shift of reflected ?0 ~ 780.24 nm light directly into transmitted light intensity. The single-point RALF apparatus used in these experiments is fiber optic based, and incorporates a simultaneous PDV measurement channel as an ``internal standard'' for validation of the RALF results. Future plans include ``line-RALF'' experiments with streak camera detection, and two-dimensional surface velocity mapping using pulsed laser illumination and gated intensified CCD camera detection. [RW PA#4931

  3. Frequency stability comparison of diode lasers locked to Doppler and sub-Doppler resonances

    Science.gov (United States)

    Affolderbach, C.; Andreeva, Ch.; Cartaleva, Stefka S.; Mileti, Gaetano; Slavov, Dimitar G.

    2004-06-01

    We present a systematic quantitative comparison of the performance parameters of two Extended Cavity Diode Lasers (ECDL), stabilized to Doppler and sub-Doppler profiles. The experimental study is carried out on Rb atomic vapour cells. The frequency shift of the resonance under investigation with respect to a reference resonance is measured and analyzed, in dependence on the modulation amplitude, cell temperature, laser power, applied magnetic field and misalignment of the pump-probe beams angle. The Allan variance is measured for both locking methods. It shows that the stabilization to the Doppler profile results in about one order of magnitude lower stability than the one to SA resonances for the short-term measurement. However, the stability achieved using both methods is sufficient for many applications and for some of them the simplicity of the Doppler locking method can be advantageous.

  4. Doppler echocardiography: Quantitative methods of pulsed and continuous wave cardiac doppler

    International Nuclear Information System (INIS)

    This book is written in workbook format and presents basic physical principles involved in the Doppler flow velocity recording in both normal and abnormal states. Formulas necessary in the computation of valve gradients, valve areas, and cardiac outputs are included

  5. On acceleration dependence of Doppler effect in light

    Indian Academy of Sciences (India)

    Sanjay M Wagh

    2013-09-01

    Using only the geometric relationships of suitable locations, we analyse Doppler effect in light to show how the acceleration of the source also contributes to the Doppler shift. We further propose that an experiment be performed using cyclotron-type devices to determine the acceleration dependence of the Doppler shift.

  6. Equipment for flow measurements according to the ultrasonic Doppler method

    International Nuclear Information System (INIS)

    An instrument for flow measurements according to the ultrasonic Doppler method is described. It consists of an applicator with an ultrasonic oscillator and, connected to it, a Doppler instrument for the Doppler flow record. The angle of incidence of the ultrasonic beam may be taken into account, flow measurement independent of the angle thus becoming possible. (RW)

  7. 21 CFR 892.1550 - Ultrasonic pulsed doppler imaging system.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ultrasonic pulsed doppler imaging system. 892.1550... (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1550 Ultrasonic pulsed doppler imaging system. (a) Identification. An ultrasonic pulsed doppler imaging system is a device that combines...

  8. Applications of doppler effect in navigation and oceanography

    Digital Repository Service at National Institute of Oceanography (India)

    Joseph, A.

    . The Doppler effect is also used in sports, through Doppler radar systems to measure ball speed. Navigation technology received a boost in the 1960s with the introduction of the satellite navigation system, which applies the Doppler effect. In this system...

  9. Two-detector doppler broadening of annihilation radiation in metals

    International Nuclear Information System (INIS)

    Recently, a new digitalized 2-Detector Doppler Broadening Spectrometer is developed. 10 pure metal samples are studied with this system. The results show the relationship between 2-D Doppler broadening spectra and electronic structure of these elements. This article introduces the spectrometer, data analysis, the Doppler broadening of 10 pure metal samples, and the discussion about these results. (author)

  10. Princípios físicos do Doppler em ultra-sonografia Physical principles of Doppler ultrasonography

    OpenAIRE

    Cibele Figueira Carvalho; Maria Cristina Chammas; Giovanni Guido Cerri

    2008-01-01

    A ultra-sonografia Doppler é um método relativamente recente dentro da rotina veterinária que fornece informações em tempo real da arquitetura vascular e dos aspectos hemodinâmicos dos vasos sanguíneos examinados em diversos órgãos vitais. Pode determinar a presença, a direção e o tipo de fluxo sanguíneo. Esta revisão de literatura compila as informações sobre os princípios físicos da ultra-sonografia Doppler. A ampliação do conhecimento desta tecnologia possibilita a melhor compreensão das a...

  11. Assessment of coronary flow reserve with transthoracic Doppler echocardiography: comparison with intracoronary Doppler method.

    OpenAIRE

    Kim, S. M.; Shim, W J; Lim, H.E.; Hwang, G. S.; Song, W. H.; Lim, D S; Kim, Y. H.; Seo, H. S.; Oh, D. J.; Ro, Y. M.

    2000-01-01

    To evaluate the feasibility and usefulness of transthoracic Doppler echocardiography (TTDE) as a non-invasive method in recording distal anterior descending (LAD) coronary flow velocity, we compared coronary flow reserve (CFR) measured by TTDE with measurements by intracoronary Doppler wire (ICDW). Twenty-one patients without LAD stenosis were studied. ICDW performed at baseline and after intracoronary injection of 18 microg adenosine. TTDE was performed at baseline and after intravenous aden...

  12. Doppler speedometer for micro-organisms

    International Nuclear Information System (INIS)

    Objective of Investigations: Development and creation of the Doppler speedometer for micro-organisms which allows to evaluate, in a real temporal scale, variations in the state of water suspension of micro-organisms under the effect of chemical, physical and other external actions. Statement of the Problem The main problem is absence of reliable, accessible for users and simple, in view of application, Doppler speedometers for micro-organisms. Nevertheless, correlation Doppler spectrometry in the regime of heterodyning the supporting and cell-scattered laser radiation is welt known. The main idea is that the correlation function of photo-current pulses bears an information on the averages over the assembly of cell velocities. For solving the biological problems, construction of auto-correlation function in the real-time regime with the delay time values comprising, function in the real-time regime with the delay time values comprising, nearly, 100 me (10 khz) or higher is needed. Computers of high class manage this problem using but the program software. Due to this, one can simplify applications of the proposed techniques provided he creates the Doppler speedometer for micro-organism on a base of the Pentium. Expected Result Manufactured operable mock-up of the Doppler speedometer for micro-organisms in a form of the auxiliary computer block which allows to receive an information, in the real time scale, on the results of external effects of various nature on the cell assembly in transparent medium with a small volume of the studied cell suspension

  13. Doppler effect measurements of 238U

    International Nuclear Information System (INIS)

    Beams of filtered neutrons at 24 +- 0.9 keV and 144 +- 12 keV from the University of Missouri Research Facility MURR were used to measure the Doppler effect of 238U metal and 238U in U3O8. The Doppler effect is caused by the broadening of the nuclear resonances in the total cross sections due to the thermal motions of the nuclei. From good geometry transmission measurements, the effective average total cross section EATCS for both kinds of sample were measured as functions of sample thickness and temperature. The temperature of the Doppler effect measurements ranged from 38 to 11000K. Temperature related density effects were removed by measuring simultaneously the gamma rays passing through the samples. Good agreement was obtained when these density changes were compared to areal density changes calculated from measured linear expansion coefficients. The EATCS data were fit with cross sections calculated from a ladder of resonances as a function of sample thickness at room temperature. This ladder was generated from a set of nuclear parameters. The set of nuclear parameters agrees with other sets used to fit 238U cross section data at lower neutron energies. The total cross sections extrapolated to zero thickness are 13.5 +- 0.2 barns at 24 keV and 11.9 +- 0.2 barns at 144 keV. THe value at 24 keV agrees with the ENDF/B-IV, while the value at 14 keV agrees with the ENDF/B-IV, while the value at 144 keV is approx. 4% greater. An expression was developed to relate the data to the Doppler coefficient in fast reactors. The absolute value of the Doppler coefficient at the two energies agreed wih values obtained from other methods

  14. A Multiple-Doppler Synthesis and Continuity Adjustment Technique (MUSCAT) to Recover Wind Components from Doppler Radar Measurements

    OpenAIRE

    Bousquet, Olivier; Chong, Michel

    1998-01-01

    A new approach is presented to account for a simultaneous solution of the three wind components from at least a pair of Doppler radar observations, which could remove potential drawbacks of an iterative (nonsimultaneous) solution of Cartesian dual-Doppler analysis techniques. The multiple-Doppler synthesis and continuity adjustment technique (MUSCAT) is derived from the extended overdetermined dual-Doppler (EODD) variational formalism that contains the basis for a simultaneous (noniterative) ...

  15. The Novel Nonlinear Adaptive Doppler Shift Estimation Technique and the Coherent Doppler Lidar System Validation Lidar

    Science.gov (United States)

    Beyon, Jeffrey Y.; Koch, Grady J.

    2006-01-01

    The signal processing aspect of a 2-m wavelength coherent Doppler lidar system under development at NASA Langley Research Center in Virginia is investigated in this paper. The lidar system is named VALIDAR (validation lidar) and its signal processing program estimates and displays various wind parameters in real-time as data acquisition occurs. The goal is to improve the quality of the current estimates such as power, Doppler shift, wind speed, and wind direction, especially in low signal-to-noise-ratio (SNR) regime. A novel Nonlinear Adaptive Doppler Shift Estimation Technique (NADSET) is developed on such behalf and its performance is analyzed using the wind data acquired over a long period of time by VALIDAR. The quality of Doppler shift and power estimations by conventional Fourier-transform-based spectrum estimation methods deteriorates rapidly as SNR decreases. NADSET compensates such deterioration in the quality of wind parameter estimates by adaptively utilizing the statistics of Doppler shift estimate in a strong SNR range and identifying sporadic range bins where good Doppler shift estimates are found. The authenticity of NADSET is established by comparing the trend of wind parameters with and without NADSET applied to the long-period lidar return data.

  16. [Echo-Doppler study of musical heart murmurs].

    Science.gov (United States)

    Boccardi, L; Pennestrì, F; Minardi, G; Di Segni, M; Pucci, E; Biasucci, L M; Loperfido, F; Ferrari, O; Giovannini, E

    1988-04-01

    The origin of systolic or diastolic musical murmurs was investigated by means of echo-doppler examination in 51 patients with various cardiac diseases. In all cases a typical doppler spectrum was identified, showing bi-directional clusters of frequencies which were concentric in systole and parallel in diastole. The doppler audio signal was musical. A similar echo-doppler signal was obtained by a diapason vibrating in isotonic solution. These data allowed us to identify the site of the vibrating cardiac structure causing the typical echo-doppler spectrum and characteristic audio signal. PMID:3181660

  17. Applications of Doppler imaging in the musculoskeletal system.

    Science.gov (United States)

    Teh, James

    2006-01-01

    Pathological conditions affecting the musculoskeletal system often result in alterations of regional blood flow. The assessment of a Doppler signal in inflammatory or infective processes complements the grayscale findings, helping to evaluate the severity of disease. Doppler imaging can also be used to determine therapeutic response or help guide injections. In addition, Doppler interrogation enables vascular characterization of solid masses. The presence of a Doppler signal can also help differentiate solid from cystic lesions. This article reviews the wide range of applications for Doppler imaging of the musculoskeletal system. PMID:16399237

  18. The Multiple Doppler Radar Workshop, November 1979.

    Science.gov (United States)

    Carbone, R. E.; Harris, F. I.; Hildebrand, P. H.; Kropfli, R. A.; Miller, L. J.; Moninger, W.; Strauch, R. G.; Doviak, R. J.; Johnson, K. W.; Nelson, S. P.; Ray, P. S.; Gilet, M.

    1980-10-01

    The findings of the Multiple Doppler Radar Workshop are summarized by a series of six papers. Part I of this series briefly reviews the history of multiple Doppler experimentation, fundamental concepts of Doppler signal theory, and organization and objectives of the Workshop. Invited presentations by dynamicists and cloud physicists are also summarized.Experimental design and procedures (Part II) are shown to be of critical importance. Well-defined and limited experimental objectives are necessary in view of technological limitations. Specified radar scanning procedures that balance temporal and spatial resolution considerations are discussed in detail. Improved siting for suppression of ground clutter as well as scanning procedures to minimize errors at echo boundaries are discussed. The need for accelerated research using numerically simulated proxy data sets is emphasized.New technology to eliminate various sampling limitations is cited as an eventual solution to many current problems in Part III. Ground clutter contamination may be curtailed by means of full spectral processing, digital filters in real time, and/or variable pulse repetition frequency. Range and velocity ambiguities also may be minimized by various pulsing options as well as random phase transmission. Sidelobe contamination can be reduced through improvements in radomes, illumination patterns, and antenna feed types. Radar volume-scan time can be sharply reduced by means of wideband transmission, phased array antennas, multiple beam antennas, and frequency agility.Part IV deals with synthesis of data from several radars in the context of scientific requirements in cumulus clouds, widespread precipitation, and severe convective storms. The important temporal and spatial scales are examined together with the accuracy required for vertical air motion in each phenomenon. Factors that introduce errors in the vertical velocity field are identified and synthesis techniques are discussed separately for the dual Doppler and multiple Doppler cases. Various filters and techniques, including statistical and variational approaches, are mentioned. Emphasis is placed on the importance of experiment design and procedures, technological improvements, incorporation of all information from supporting sensors, and analysis priority for physically simple cases. Integrated reliability is proposed as an objective tool for radar siting.Verification of multiple Doppler-derived vertical velocity is discussed in Part V. Three categories of verification are defined as direct, deductive, and theoretical/numerical. Direct verification consists of zenith-pointing radar measurements (from either airborne or ground-based systems), air motion sensing aircraft, instrumented towers, and tracking of radar chaff. Deductive sources include mesonetworks, aircraft (thermodynamic and microphysical) measurements, satellite observations, radar reflectivity, multiple Doppler consistency, and atmospheric soundings. Theoretical/numerical sources of verification include proxy data simulation, momentum checking, and numerical cloud models. New technology, principally in the form of wide bandwidth radars, is seen as a development that may reduce the need for extensive verification of multiple Doppler-derived vertical air motions. Airborne Doppler radar is perceived as the single most important source of verification within the bounds of existing technology.Nine stages of data processing and display are identified in Part VI. The stages are identified as field checks, archival, selection, editing, coordinate transformation, synthesis of Cartesian fields, filtering, display, and physical analysis. Display of data is considered to be a problem critical to assimilation of data at all stages. Interactive computing systems and software are concluded to be very important, particularly for the editing stage. Three- and 4-dimensional displays are considered essential for data assimilation, particularly at the physical analysis stage. The concept of common data tape formats is approved both for data in radar s

  19. Power and color Doppler ultrasound settings for inflammatory flow

    DEFF Research Database (Denmark)

    Torp-Pedersen, Søren; Christensen, Robin; Szkudlarek, Marcin; Ellegaard, Karen; D'Agostino, Maria Antonietta; Iagnocco, Annamaria; Naredo, Esperanza; Balint, Peter; Wakefield, Richard J; Torp-Pedersen, Arendse; Terslev, Lene

    2015-01-01

    OBJECTIVE: To determine how settings for power and color Doppler ultrasound sensitivity vary on different high- and intermediate-range ultrasound machines and to evaluate the impact of these changes on Doppler scoring of inflamed joints. METHODS: Six different types of ultrasound machines were used....... On each machine, the factory setting for superficial musculoskeletal scanning was used unchanged for both color and power Doppler modalities. The settings were then adjusted for increased Doppler sensitivity, and these settings were designated study settings. Eleven patients with rheumatoid arthritis...... (RA) with wrist involvement were scanned on the 6 machines, each with 4 settings, generating 264 Doppler images for scoring and color quantification. Doppler sensitivity was measured with a quantitative assessment of Doppler activity: color fraction. Higher color fraction indicated higher sensitivity...

  20. Design of a Doppler reflectometer for KSTAR

    Energy Technology Data Exchange (ETDEWEB)

    Lee, K. D., E-mail: kdlee@nfri.re.kr; Nam, Y. U.; Seo, Seong-Heon; Kim, Y. S. [National Fusion Research Institute, Yuseong, Daejeon 305-333 (Korea, Republic of)

    2014-11-15

    A Doppler reflectometer has been designed to measure the poloidal propagation velocity on the Korea Superconducting Tokamak Advanced Research (KSTAR) tokamak. It has the operating frequency range of V-band (50-75 GHz) and the monostatic antenna configuration with extraordinary mode (X-mode). The single sideband modulation with an intermediate frequency of 50 MHz is used for the heterodyne measurement with the 200 MHz in-phase and quadrature (I/Q) phase detector. The corrugated conical horn antenna is used to approximate the Gaussian beam propagation and it is installed together with the oversized rectangular waveguides in the vacuum vessel. The first commissioning test of the Doppler reflectometer system on the KSTAR tokamak is planned in the 2014 KSTAR experimental campaign.

  1. Considerations for Calibrating a Laser Doppler Anemometer

    Energy Technology Data Exchange (ETDEWEB)

    Duncan, Michael L [ORNL; Keck, Joe [ORNL

    2010-01-01

    Laser Doppler Anemometers have long been the device-of-choice for air velocity measurements due to their avoidance of turbulence induced by insertion-method air velocity measurement devices. At first glance, the use of a Laser Doppler Anemometer (LDA) for calibrating air velocity meters appears to be a relatively simple and straightforward process. As is typical in most metrological applications the process becomes much more complex when attempting to use the apparatus to make high-performance, metrology measurements. This paper focuses on the considerations for calibration of a LDA beginning with a discussion why an LDA needs to be calibrated. Other areas of discussion include alignment of the optics, dealing with imperfections in the alignment process, establishing the traceability of measurements from the apparatus and design and development of and experiences with using a calibration apparatus.

  2. Spatial and Wavenumber Resolution of Doppler Reflectometry

    CERN Document Server

    Surkov, A; Surkov, Alexander; Gusakov, Evgeniy

    2004-01-01

    Doppler reflectometry spatial and wavenumber resolution is analyzed within the framework of the linear Born approximation in slab plasma model. Explicit expression for its signal backscattering spectrum is obtained in terms of wavenumber and frequency spectra of turbulence which is assumed to be radially statistically inhomogeneous. Scattering efficiency for both back and forward scattering (in radial direction) is introduced and shown to be inverse proportional to the square of radial wavenumber of the probing wave at the fluctuation location thus making the spatial resolution of diagnostics sensitive to density profile. It is shown that in case of forward scattering additional localization can be provided by the antenna diagram. It is demonstrated that in case of backscattering the spatial resolution can be better if the turbulence spectrum at high radial wavenumbers is suppressed. The improvement of Doppler reflectometry data localization by probing beam focusing onto the cut-off is proposed and described....

  3. Minior Actinide Doppler Coefficient Measurement Assessment

    International Nuclear Information System (INIS)

    The 'Minor Actinide Doppler Coefficient Measurement Assessment' was a Department of Energy (DOE) U-NERI funded project intended to assess the viability of using either the FLATTOP or the COMET critical assembly to measure high temperature Doppler coefficients. The goal of the project was to calculate using the MCNP5 code the gram amounts of Np-237, Pu-238, Pu-239, Pu-241, AM-241, AM-242m, Am-243, and CM-244 needed to produce a 1E-5 in reactivity for a change in operating temperature 800C to 1000C. After determining the viability of using the assemblies and calculating the amounts of each actinide an experiment will be designed to verify the calculated results. The calculations and any documented experiments are designed to support the Advanced Fuel Cycle Initiative in conducting safety analysis of advanced fast reactor or accelerator-driven transmutation systems with fuel containing high minor actinide content

  4. Laser Doppler measurement of cutaneous blood flow

    International Nuclear Information System (INIS)

    Laser Doppler velocimetry is an instrument system which has only recently been applied to the evaluation and quantitation of perfusion in the micro-vascular bed. The instrument is based on the Doppler principle, but uses low power laser light rather than the more commonly used ultrasound, and has a sample volume of approximately 1 mm/sup 3/. As it is non-invasive, it can be used on any skin surface or exposed microvascular bed and provides a continuous semi-quantitative measure of microcirculatory perfusion, it has a number of advantages as compared to other cutaneous blood flow measurement techniques. Initial studies have shown that it is easily used, and it has demonstrated good correlation with both xenon radio-isotope clearance and microsphere deposition techniques. Areas of current evaluation and utilization are in most major areas of medicine and surgery and include plastic, vascular and orthopaedic surgery, dermatology, gastro-enterology, rheumatology, burns and anaesthesiology

  5. Transcranial Doppler sonography in familial hemiplegic migraine

    Energy Technology Data Exchange (ETDEWEB)

    Pierelli, F.; Pauri, F.; Cupini, L.M.; Fiermonte, G.; Rizzo, P.A. (Universita la Sapienza, Roma (Italy))

    1991-02-01

    A patient affected by familial hemiplegic migraine underwent transcranial Doppler sonography twice: the first during a spontaneous attack with right hemiparesis and aphasia, the second during a headachefree period. During the attack the following haemodynamic changes were seen: (a) bilateral increase in the middle cerebral artery and anterior cerebral artery blood flow velocities (this increase was more pronounced on the left side), (b) decreased systo-diastolic ratio and pulsatility index on the right side, (c) increased systo-diastolic ratio and pulsatility index on the left side. The results indicate that during the attack in this familial hemiplegic migraine patient, a diffuse vasoconstriction of the basal cerebral arteries developed. Moreover, transcranial Doppler sonography data suggest that a prolonged vasoconstriction of the peripheral arterioles could play a role in determining the neurological symptoms in this syndrome. 13 refs., 1 figs., 1 tab.

  6. Color Doppler US of the penis

    Energy Technology Data Exchange (ETDEWEB)

    Bertolotto, Michele (ed.) [Trieste Univ. Ospedale di Cattinara (Italy). Dept. Radiology

    2008-07-01

    This book provides a comprehensive reference and practical guide on the application of US to penile diseases and conditions. After introductory chapters on technical requirements and penile anatomy, subsequent chapters offer a systematic overview of the diverse applications of color Doppler US. The topics covered include erectile dysfunction, Peyronie's disease, priapism, trauma, tumors, the postoperative penis, inflammation, and fibrosis. Each topic is introduced by a clinical overview with the purpose of clarifying the problems and elucidating what the urologist may expect from color Doppler US. Thereafter, performance of the US study is explained and the pathological anatomy reviewed. High-quality images obtained with high-end US equipment are included. Each chapter also contains a section on the diagnostic information provided by other imaging modalities, and in particular MRI. (orig.)

  7. Doppler Spectrum Estimation by Ramanujan Fourier Transforms

    CERN Document Server

    Lagha, M; Lagha, Mohand; Bensebti, Messaoud

    2006-01-01

    The Doppler spectrum estimation of a weather radar signal in a classic way can be made by two methods, temporal one based in the autocorrelation of the successful signals, whereas the other one uses the estimation of the power spectral density PSD by using Fourier transforms. We introduces a new tool of signal processing based on Ramanujan sums cq(n), adapted to the analysis of arithmetical sequences with several resonances p/q. These sums are almost periodic according to time n of resonances and aperiodic according to the order q of resonances. New results will be supplied by the use of Ramanujan Fourier Transform (RFT) for the estimation of the Doppler spectrum for the weather radar signal.

  8. Renal duplex Doppler ultrasound findings in diabetics

    International Nuclear Information System (INIS)

    The correlation between clinical-laboratory findings and renal duplex Doppler ultrasound findings was studied in 45 patients with diabetes mellitus to see the role of duplex Doppler ultrasound in the detection of diabetic nephropathy. The resistive indices in patients with elevated serum creatinine, BUN, proteinuria, and systolic blood pressure levels were statistically significantly higher than those in patients with normal levels (p<0.05). Also resistive indics in patients with retinopathy were higher than that in patients without retinopathy (p<0.05). But the ultrasound morphologic changes of kidney such as renal length, cortical eye-catching, and corticomedullarycontrast were not well correlated with clinical-laboratory data and resistive index. The resistive index of the kidney in conjunction with clinical-laboratory data in diabetics may be helpful in the evaluation of diabetic nephropathy

  9. Measuring Doppler Beaming with Kepler and TESS

    Science.gov (United States)

    Mayorga, Laura; Jackiewicz, Jason

    2016-01-01

    The Kepler mission offered unparalleled insight into stellar systems. Due to Kepler's high precision photometry, we can study the reflected light from a planet, the ellipsoidal variations of a star, and the small Doppler beaming signal due to the gravitational interaction between a planet and host star. To predict how the beaming signal varies as a function of stellar system parameters, we numerically simulate the beaming signals both Kepler and the upcoming Transiting Exoplanet Survey Satellite (TESS) would detect. We predict what mass planets TESS will be capable of detecting given the solar neighborhood population of stars and known population of exoplanets. Doppler beaming is largest for massive, short-period planets around cool stars and is more easily detectable by Kepler than TESS. Kepler's advantage is its bluer bandpass, longer time baseline, and higher precision.

  10. Color Doppler US of the penis

    International Nuclear Information System (INIS)

    This book provides a comprehensive reference and practical guide on the application of US to penile diseases and conditions. After introductory chapters on technical requirements and penile anatomy, subsequent chapters offer a systematic overview of the diverse applications of color Doppler US. The topics covered include erectile dysfunction, Peyronie's disease, priapism, trauma, tumors, the postoperative penis, inflammation, and fibrosis. Each topic is introduced by a clinical overview with the purpose of clarifying the problems and elucidating what the urologist may expect from color Doppler US. Thereafter, performance of the US study is explained and the pathological anatomy reviewed. High-quality images obtained with high-end US equipment are included. Each chapter also contains a section on the diagnostic information provided by other imaging modalities, and in particular MRI. (orig.)

  11. [Catheter-induced femoral artery lesions: diagnosis with B-mode ultrasound, Doppler ultrasound and color Doppler ultrasound].

    Science.gov (United States)

    Steinkamp, H J; Jochens, R; Zendel, W; Zwicker, C; Hepp, W; Felix, R

    1992-10-01

    A total of 44 patients were evaluated to compare the value of B-mode sonography, Doppler sonography and colour coded Doppler sonography. All patients were studied because of suspected lesions of the femoral arteries following diagnostic and/or therapeutic cardiac catheterisation. B-mode sonography was unable to reliably differentiate between haematoma and pseudo-aneurysms, a.v.-fistula or combined lesions. Colour coded Doppler sonography can better demonstrate haematoma and thrombi in pseudo-aneurysms. The neck of a pseudoaneurysm can be exactly depicted by colour coded Doppler sonography. A.v.-fistula is shown by colour coded Doppler sonography based on typical colour coding and the Doppler spectrum. Combined lesions of pseudo-aneurysm and a.v.-fistula cannot reliably be detected by colour coded Doppler sonography, duplex sonography and B-mode sonography. PMID:1439718

  12. Spatial and Wavenumber Resolution of Doppler Reflectometry

    OpenAIRE

    Gusakov, Evgeniy; Surkov, Alexander

    2004-01-01

    Doppler reflectometry spatial and wavenumber resolution is analyzed within the framework of the linear Born approximation in slab plasma model. Explicit expression for its signal backscattering spectrum is obtained in terms of wavenumber and frequency spectra of turbulence which is assumed to be radially statistically inhomogeneous. Scattering efficiency for both back and forward scattering (in radial direction) is introduced and shown to be inverse proportional to the squar...

  13. Sub-Nyquist Radar via Doppler Focusing

    OpenAIRE

    Bar-Ilan, Omer; Eldar, Yonina C

    2012-01-01

    We investigate the problem of a monostatic pulse-Doppler radar transceiver trying to detect targets, sparsely populated in the radar's unambiguous time-frequency region. Several past works employ compressed sensing (CS) algorithms to this type of problem, but either do not address sample rate reduction, impose constraints on the radar transmitter, propose CS recovery methods with prohibitive dictionary size, or perform poorly in noisy conditions. Here we describe a sub-Nyquist sampling and re...

  14. Radar target micro-doppler signature classification

    OpenAIRE

    Smith, G. E.

    2008-01-01

    This thesis reports on research into the field of Micro-Doppler Signature (μ-DS) based radar Automatic Target Recognition (ATR) with additional contributions to general radar ATR methodology. The μ-DS based part of the research contributes to three distinct areas: time domain classification; frequency domain classification; and multiperspective μ-DS classification that includes the development of a theory for the multistatic μ-DS. The contribution to general radar ATR is the proposal of a ...

  15. Influence of Doppler ultrasound on fetal activity.

    OpenAIRE

    Murrills, A J; Barrington, P; Harris, P. D.; Wheeler, T

    1983-01-01

    A randomised and double blind study of 100 subjects and 50 controls was performed to confirm or refute a report from Cardiff in 1975 that continuous Doppler ultrasound, as used in fetal heart rate monitoring, increases fetal movement by over 90%. The results showed such an effect to be most unlikely (power greater than 0.99). A total of 150 pregnant mothers recorded fetal movements for 30 minutes while connected to a specially modified cardiotocograph, the ultrasound being switched on at rand...

  16. Doppler Spectrum Estimation by Ramanujan Fourier Transforms

    OpenAIRE

    Lagha, Mohand; Bensebti, Messaoud

    2006-01-01

    The Doppler spectrum estimation of a weather radar signal in a classic way can be made by two methods, temporal one based in the autocorrelation of the successful signals, whereas the other one uses the estimation of the power spectral density PSD by using Fourier transforms. We introduces a new tool of signal processing based on Ramanujan sums cq(n), adapted to the analysis of arithmetical sequences with several resonances p/q. These sums are almost periodic according to ti...

  17. Colour Doppler ultrasound of the penis

    Energy Technology Data Exchange (ETDEWEB)

    Wilkins, C.J.; Sriprasad, S.; Sidhu, P.S. E-mail: paulsidhu@compuserve.com

    2003-07-01

    Because it is a superficial structure, the penis is ideally suited to ultrasound imaging. A number of disease processes, including Peyronie's disease, penile fractures and penile tumours, are clearly visualized with ultrasound. An assessment of priapism can also be made using spectral Doppler waveform technology. Furthermore, dynamic assessment of cavernosal arterial changes after pharmaco-stimulation allows diagnosis of arterial and venogenic causes for impotence. This pictorial review illustrates the range of diseases encountered with ultrasound of the penis.

  18. Rotational Doppler beaming in eclipsing binaries

    OpenAIRE

    Groot, Paul J

    2011-01-01

    In eclipsing binaries the stellar rotation of the two components will cause a rotational Doppler beaming during eclipse ingress and egress when only part of the eclipsed component is covered. For eclipsing binaries with fast spinning components this photometric analogue of the well-known spectroscopic Rossiter-McLaughlin effect can exceed the strength of the orbital effect. Example light curves are shown for a detached double white dwarf binary, a massive O-star binary and a...

  19. Poincare's relativistic Doppler-Fizeau formula

    OpenAIRE

    Pierseaux, Yves

    2006-01-01

    We deduce from Poincare's ellipsoidal wavefronts a relativistic Doppler-Fizeau formula that is not the same as 1905 Einstein's one. Longitudinally, Einstein's formula and Poincare's formula are the same. The question of an experimental test is connected with the possibility or the impossibility of directly measuring the relativistic transverse effect. Hasselkamp's 1978 experiment becomes a crucial experiment because Poincare's relativistic kinematics predicts an expansion of...

  20. Blazar sequence - an artefact of Doppler boosting

    OpenAIRE

    Nieppola, E.; Valtaoja, E.; Tornikoski, M.; Hovatta, T.; Kotiranta, M.

    2008-01-01

    The blazar sequence is a scenario in which the bolometric luminosity of the blazar governs the appearance of its spectral energy distribution. The most prominent result is the significant negative correlation between the synchrotron peak frequencies and the synchrotron peak luminosities of the blazar population. Observational studies of the blazar sequence have, in general, neglected the effect of Doppler boosting. We study the dependence of both the synchrotron peak frequen...

  1. Doppler-free magnetic optical activity

    OpenAIRE

    Giraud-Cotton, S.; Kaftandjian, V.P.; Talin, B

    1980-01-01

    The theory of Doppler-free magnetic optical activity associated with a single absorption line is presented. The transmission of tunable laser light, linearly polarized, through a dilute gaseous medium along a steady magnetic field is studied in the presence of a second counterpropagating saturating laser. The third order non linear susceptibility is calculated for a two-level system exhibiting a normal Zeeman effect, with arbitrary J values.

  2. Colour Doppler ultrasound of the penis

    International Nuclear Information System (INIS)

    Because it is a superficial structure, the penis is ideally suited to ultrasound imaging. A number of disease processes, including Peyronie's disease, penile fractures and penile tumours, are clearly visualized with ultrasound. An assessment of priapism can also be made using spectral Doppler waveform technology. Furthermore, dynamic assessment of cavernosal arterial changes after pharmaco-stimulation allows diagnosis of arterial and venogenic causes for impotence. This pictorial review illustrates the range of diseases encountered with ultrasound of the penis

  3. Image processing techniques for Doppler global velocimetry

    OpenAIRE

    Manners, R. J.; Ainsworth, Roger

    1997-01-01

    There is a demand for a whole field velocimetry technique which offers the capability of rapid characterisation of complex engineering flow fields. This thesis describes a research programme aimed at the development of a reliable Doppler global velocimeter, suited to the measurement of such flows. The programme of work undertaken is discussed with reference both to research undertaken elsewhere and to previous work on the system at Oxford. While much of the underlying technology required for ...

  4. Doppler sonographic findings in testicular microlithiasis

    Directory of Open Access Journals (Sweden)

    Selim Serter

    2008-08-01

    Full Text Available OBJECTIVE: The aim of this prospective study was to compare the resistive index (RI values, which is a parameter of testicular parenchymal perfusion, in testicular microlithiasis (TM cases and normal cases. MATERIALS AND METHODS: 2179 volunteers, all healthy men (17-42 years of age from the Annual Army Reserve Officer Training Corps training camp were included in the study. A screening scrotal ultrasound was performed and all men diagnosed with TM underwent a scrotal Doppler ultrasonography scan (US. US examinations were performed for subjects with TM and without TM as a control group and RI was determined. RESULTS: 53 men with TM were identified in the 2179 US. Spectral Doppler examination was applied to 50 randomly selected cases (100 testicles without TM and 92 testicles with TM, 39 cases (78 testicles with bilateral and 14 cases with unilateral involvement. However, 48 normal testicles (17 bilateral and 14 unilateral and 47 testicles with TM (15 bilateral and 17 unilateral, 10 of which were cases with bilateral TM where flow from the centripetal artery could be obtained and analyzed were included in the statistical analysis for resistive indices. There was no significant difference regarding the RI and spectral examinations between subjects with and without TM. An interesting finding was the twinkling artifact observed in three cases. CONCLUSION: Microliths did not alter the RI values and thus had no influence on testicular perfusion on Doppler US examination.

  5. Precise Doppler Monitoring of Barnard's Star

    CERN Document Server

    Choi, Jieun; Marcy, Geoffrey W; Howard, Andrew W; Fischer, Debra A; Johnson, John A; Isaacson, Howard; Wright, Jason T

    2012-01-01

    We present 248 precise Doppler measurements of Barnard's Star (Gl 699), the second nearest star system to Earth, obtained from Lick and Keck Observatories during 25 years between 1987 and 2012. The early precision was 20 \\ms{} but was 2 \\ms{} during the last 8 years, constituting the most extensive and sensitive search for Doppler signatures of planets around this stellar neighbor. We carefully analyze the 136 Keck radial velocities spanning 8 years by first applying a periodogram analysis to search for nearly circular orbits. We find no significant periodic Doppler signals with amplitudes above $\\sim$2 \\ms{}, setting firm upper limits on the minimum mass (\\msini) of any planets with orbital periods from 0.1 to 1000 days. Using a Monte Carlo analysis for circular orbits, we determine that planetary companions to Barnard's Star with masses above 2 \\mearth{} and periods below 10 days would have been detected. Planets with periods up to 2 years and masses above 10 \\mearth{} (0.03 \\mjup) are also ruled out. A sim...

  6. Doppler Lidar for Wind Measurements on Venus

    Science.gov (United States)

    Singh, Upendra N.; Emmitt, George D.; Yu, Jirong; Kavaya, Michael J.

    2010-01-01

    NASA Langley Research Center has a long history of developing 2-micron laser transmitter for wind sensing. With support from NASA Laser Risk Reduction Program (LRRP) and Instrument Incubator Program (IIP), NASA Langley Research Center has developed a state-of-the-art compact lidar transceiver for a pulsed coherent Doppler lidar system for wind measurement. The transmitter portion of the transceiver employs the high-pulse-energy, Ho:Tm:LuLiF, partially conductively cooled laser technology developed at NASA Langley. The transceiver is capable of 250 mJ pulses at 10 Hz. It is very similar to the technology envisioned for coherent Doppler lidar wind measurements from Earth and Mars orbit. The transceiver is coupled to the large optics and data acquisition system in the NASA Langley VALIDAR mobile trailer. The large optics consists of a 15-cm off-axis beam expanding telescope, and a full-hemispheric scanner. Vertical and horizontal vector winds are measured, as well as relative backscatter. The data acquisition system employs frequency domain velocity estimation and pulse accumulation. It permits real-time display of the processed winds and archival of all data. This lidar system was recently deployed at Howard University facility in Beltsville, Mary-land, along with other wind lidar systems. Coherent Doppler wind lidar ground-based wind measurements and comparisons with other sensors will be presented. A simulation and data product for wind measurement at Venus will be presented.

  7. Computer vision approach for ultrasound Doppler angle estimation.

    Science.gov (United States)

    Saad, Ashraf A; Loupas, Thanasis; Shapiro, Linda G

    2009-12-01

    Doppler ultrasound is an important noninvasive diagnostic tool for cardiovascular diseases. Modern ultrasound imaging systems utilize spectral Doppler techniques for quantitative evaluation of blood flow velocities, and these measurements play a crucial rule in the diagnosis and grading of arterial stenosis. One drawback of Doppler-based blood flow quantification is that the operator has to manually specify the angle between the Doppler ultrasound beam and the vessel orientation, which is called the Doppler angle, in order to calculate flow velocities. In this paper, we will describe a computer vision approach to automate the Doppler angle estimation. Our approach starts with the segmentation of blood vessels in ultrasound color Doppler images. The segmentation step is followed by an estimation technique for the Doppler angle based on a skeleton representation of the segmented vessel. We conducted preliminary clinical experiments to evaluate the agreement between the expert operator's angle specification and the new automated method. Statistical regression analysis showed strong agreement between the manual and automated methods. We hypothesize that the automation of the Doppler angle will enhance the workflow of the ultrasound Doppler exam and achieve more standardized clinical outcome. PMID:18488268

  8. Principales aplicaciones del Doppler color transvaginal Main applications of transvaginal color doppler

    Directory of Open Access Journals (Sweden)

    Miguel Pérez Ramírez

    1997-12-01

    Full Text Available Se realiza una revisión bibliográfica acerca de esta novedosa técnica ecográfica (doppler color. Se indican sus principales aplicaciones en Obstetricia durante el primer trimestre del embarazo debido a sus manifiestas ventajas sobre otras técnicas. Se destaca también la importancia que tiene para la detección y control de afecciones de la esfera ginecológica.A bibliographic review is made on this novel echographic technique (doppler color. Its main applications in Obstetrics during the first trimester of pregnancy are suggested due to its advantages upon other techniques. The importance of this technique for the detection and control of disorders within the gynecologic field are also highlighted.

  9. Recommendations for terminology and display for doppler echocardiography

    International Nuclear Information System (INIS)

    Doppler echocardiography has recently emerged as a major noninvasive technique with many applications in cardiology. To a large extent, this has been based upon a combination of clinical and engineering advances which now make possible the use of quantitative Doppler echocardiography in combination with two-dimensional imaging for measurement of volume flows, transvalve gradients, and other physiologic flow parameters which reflect cardiac function. It was the purpose of this Committee to provide a glossary of terms which could be used in standard fashion for papers and discussions related to Doppler echocardiography. As part of its task, the Committee also undertook an attempt to recommend a standard for display of Doppler information which would be useful, both for manufacturers and for clinicians. The document, therefore, includes: Section I, the Committee's recommendations for Doppler display. Section II, the glossary of Doppler terms, related to engineering and to clinical applications

  10. Shigeo Satomura: 60 years of Doppler ultrasound in medicine.

    Science.gov (United States)

    Coman, Ioan M; Popescu, Bogdan A

    2015-01-01

    This year we celebrate 60 years since Shigeo Satomura published the first measurements of the Doppler shift of ultrasonic signals from a beating heart. He demonstrated that Doppler signals can be retrieved from heart movements when insonated with 3 MHz ultrasonic waves. Later, togheter with Ziro Kaneko, he constructed the first Doppler flowmeter to measure the blood flow velocities in peripheral and extracranial brain-supplying vessels using ultrasounds. They proved that ultrasonic Doppler signals from arteries and veins can be recorded from the surface of the skin and pioneered transcutaneous flow analysis in systole and diastole in both normal and diseased blood vessels. These were the first medical applications of Doppler sonography and impressive technologic innovations have been continuing ever since. Over time, Doppler techniques became a key player in diagnostic ultrasound for hemodynamic assessment, replacing cardiac catheterization in many clinical settings. PMID:26699126

  11. Doppler radar wind field retrieval over the Po Valley

    OpenAIRE

    Goh, Y. K.; Holt, A.R.; P. P. Alberoni

    2006-01-01

    Although methods of using multiple Doppler radars to study wind fields have long been proposed, and many research studies have been made, very few operational radar operators adopt methods which require the use of specific scanning strategies to allow the extraction of wind information. Here we report a collaborative study on dual-Doppler radars based on two Doppler radars in the Po valley, Italy. Unusually, the radars are only about 90 km apart, though operated by the same authority. The win...

  12. Ionospheric Doppler measurements by means of HF-radar techniques

    OpenAIRE

    Altadill, D.; C.Bianchi

    2005-01-01

    Studies of the dynamics of the ionosphere and its related phenomena are mainly based on Doppler Drift measurements. The time variation (ionisation/recombination) of plasma density, thermospheric wind and others can be observed by means of HF-radars. The technique of Doppler Drift measurements is a quite complex technique that is now affordable by means of an advanced ionospheric sounder. The combination of vertical sounding and interferometric Doppler detection discloses the Doppl...

  13. Spacecraft Doppler Tracking as a Xylophone Detector of Gravitational Radiation

    Science.gov (United States)

    Tinto, M.

    1995-01-01

    Spacecraft Doppler tracking is discussed for detecting gravitational waves in which Doppler data recorded on the ground are linearly combined with Doppler measurements made on board a spacecraft. A new method is derived for removing from combined data the frequency fluctuations due to the Earth troposphere, ionosphere, and mechanical vibrations of the antenna on the ground. The remaining non-zero gravitational wave signal could be used for detecting gravitational waves.

  14. Analysis on rotational Doppler Effect based on modal expansion method

    CERN Document Server

    Zhou, Hailong; Zhang, Pei; Zhang, Xinliang

    2015-01-01

    We theoretically investigate the optical rotational Doppler Effect using modal expansion method. We find that the frequency shift content is only determined by the surface of spinning object and the reduced Doppler shift is linear to the change of mode index. The theoretical model makes us better understand the physical processes of rotational Doppler Effect. It can provide theoretical guidance for many related applications, such as detection of rotating bodies, detection of OAM and frequency shift.

  15. Doppler-like effect and doubtful expansion of universe

    OpenAIRE

    Szaraniec, Edward

    2003-01-01

    The distance contraction, as observed in electrical soundings over horizontally stratified earth (static system), is identified as a counterpart of Doppler shift in dynamical systems. Identification of Doppler-like effect in a stock-still systems makes it possible to give an al-ternative answer to the question about an effective cause of the Doppler shift, which sounds: the inhomogeneities. This answer opens different static as well as kinematic possibilities, which challeng...

  16. Analysis on rotational Doppler Effect based on modal expansion method

    OpenAIRE

    Zhou, Hailong; Dong, Jianji; Zhang, Pei; Zhang, Xinliang

    2015-01-01

    We theoretically investigate the optical rotational Doppler Effect using modal expansion method. We find that the frequency shift content is only determined by the surface of spinning object and the reduced Doppler shift is linear to the change of mode index. The theoretical model makes us better understand the physical processes of rotational Doppler Effect. It can provide theoretical guidance for many related applications, such as detection of rotating bodies, detection of...

  17. The Impact of Stellar Oscillations on Doppler Velocity Planet Searches

    OpenAIRE

    O'Toole, S. J.; Tinney, C. G.; Jones, H. R. A.

    2007-01-01

    We present a quantitative investigation of the effect of stellar oscillations on Doppler velocity planet searches. Using data from four asteroseismological observation campaigns, we find a power law relationship between the noise impact of these oscillations on Doppler velocities and both the luminosity-to-mass of the target stars, and observed integration times. Including the impact of oscillation jitter should improve the quality of Keplerian fits to Doppler velocity data....

  18. Minimally destructive, Doppler measurement of a quantized, superfluid flow

    OpenAIRE

    Kumar, A.; Anderson, N; Phillips, W. D.; Eckel, S.; Campbell, G. K.; Stringari, S.

    2015-01-01

    The Doppler effect, the shift in the frequency of sound due to motion, is present in both classical gases and quantum superfluids. Here, we perform an in-situ, minimally destructive measurement, of the persistent current in a ring-shaped, superfluid Bose-Einstein condensate using the Doppler effect. Phonon modes generated in this condensate have their frequencies Doppler shifted by a persistent current. This frequency shift will cause a standing-wave phonon mode to be "dragg...

  19. Interpretation of Doppler blood flow velocity waveforms using neural networks.

    OpenAIRE

    Baykal, N.; Reggia, J. A.; Yalabik, N.; Erkmen, A.; Beksac, M. S.

    1994-01-01

    Doppler umbilical artery blood flow velocity waveform measurement is used in perinatal surveillance for the evaluation of pregnancy status. There is an ongoing debate on the predictive value of Doppler measurements concerning the critical effect of the selection of parameters for the evaluation of Doppler output. In this paper, we describe how neural network methods can be used both to discover relevant classification features and subsequently to classify patients. Classification accuracy var...

  20. Applications of Doppler ultrasound in clinical vascular disease

    Science.gov (United States)

    Barnes, R. W.; Hokanson, D. E.; Sumner, D. S.; Strandness, D. E., Jr.

    1975-01-01

    Doppler ultrasound has become the most useful and versatile noninvasive technique for objective evaluation of clinical vascular disease. Commercially available continuous-wave instruments provide qualitative and quantitative assessment of venous and arterial disease. Pulsed Doppler ultrasound was developed to provide longitudinal and transverse cross-sectional images of the arterial lumen with a resolution approaching that of conventional X-ray techniques. Application of Doppler ultrasound in venous, peripheral arterial, and cerebrovascular diseases is reviewed.

  1. Doppler Uterine Artery Flow Velocimetry in Prediction of Preterm Labor

    OpenAIRE

    Mahyar Mohammadi Fard; Alireza Mirgholami; Masoud Pezeshki Rad

    2009-01-01

    "nIntroduction: To evaluate the role of Doppler waveforms of the uterine vessels in predicting preterm labor. "nMaterials and Methods: This was a retrospective analysis of the uterine artery Doppler findings of 28 15-25 week singleton pregnancies with a spontaneous preterm labor were compared to 326 pregnancies delivered at term. 354 women who presented to our medical center from April 20, 2008 to November 20, 2008 were enrolled in the study. Pulsed-wave Doppler measurements were ma...

  2. Is tissue Doppler echocardiography the Holy Grail for the intensivist?

    OpenAIRE

    Poelaert, Jan; Roosens, Carl

    2007-01-01

    Assessment of left ventricular diastolic function in the critically ill patient remains a difficult issue in clinical practice. Combined use of routine transmitral and pulmonary venous Doppler patterns in conjunction with tissue Doppler imaging have been claimed to allow bedside diagnosis of diastolic dysfunction. Although in the previous issue of Critical Care it was clearly demonstrated there might be a difference in load dependency of the early myocardial tissue Doppler velocity between la...

  3. Characterization of the image-derived carotid artery input function using independent component analysis for the quantitation of [18F] fluorodeoxyglucose positron emission tomography images

    Science.gov (United States)

    Chen, K.; Chen, X.; Renaut, R.; Alexander, G. E.; Bandy, D.; Guo, H.; Reiman, E. M.

    2007-12-01

    We previously developed a noninvasive technique for the quantification of fluorodeoxyglucose (FDG) positron emission tomography (PET) images using an image-derived input function obtained from a manually drawn carotid artery region. Here, we investigate the use of independent component analysis (ICA) for more objective identification of the carotid artery and surrounding tissue regions. Using FDG PET data from 22 subjects, ICA was applied to an easily defined cubical region including the carotid artery and neighboring tissue. Carotid artery and tissue time activity curves and three venous samples were used to generate spillover and partial volume-corrected input functions and to calculate the parametric images of the cerebral metabolic rate for glucose (CMRgl). Different from a blood-sampling-free ICA approach, the results from our ICA approach are numerically well matched to those based on the arterial blood sampled input function. In fact, the ICA-derived input functions and CMRgl measurements were not only highly correlated (correlation coefficients >0.99) to, but also highly comparable (regression slopes between 0.92 and 1.09), with those generated using arterial blood sampling. Moreover, the reliability of the ICA-derived input function remained high despite variations in the location and size of the cubical region. The ICA procedure makes it possible to quantify FDG PET images in an objective and reproducible manner. Image-derived input function by ICA for FDG-PET.

  4. Evaluating Peripheral Vascular Injuries: Is Color Doppler Enough for Diagnosis?

    Directory of Open Access Journals (Sweden)

    Mohd Lateef Wani

    2014-03-01

    Full Text Available Background:: Vascular injury poses a serious threat to limb and life. Thus, diagnosis should be made immediately with minimally invasive methods. Doppler is a good aid in diagnosis of vascular injury. Methods:: The present prospective study was conducted on 150 patients who presented with soft signs (the signs which are suggestive but not confirmatory of vascular injury. They were subjected to color Doppler examination before exploration. The patients with the features of vascular injury on color Doppler were subjected to exploration. On the other hand, those who had normal Doppler were subjected to CT- angiography. Then, the findings of the exploration were matched with those of color Doppler. The data were analyzed using the SPSS statistical software. Results:: Out of the 150 Doppler examinations, 110 (73.33% were reported as positive, while 40 were reported as negative for vascular injury. These were subjected to CT-angiography and seven of them had the features of vascular injury on CT-angiography. All the patients with positive Doppler or CT angiography findings were subjected to exploration. Doppler had a sensitivity of 94% and specificity of 82.5% in diagnosis of vascular injury using Binary classification test. Conclusions:: Color Doppler is an easily available, reliable, and handy method of diagnosing a vascular injury. It has a very high sensitivity and specificity in diagnosis of vascular injuries.

  5. EUV Doppler Imaging for CubeSat Platforms Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Mature the design and fabricate the Flare Initiation Doppler Imager (FIDI) instrument to demonstrate low-spacecraft-resource EUV technology (most notably,...

  6. Eliminating Doppler Effects in Synthetic-Aperture Radar Optical Processors

    Science.gov (United States)

    Constantindes, N. J.; Bicknell, T. J.

    1984-01-01

    Pair of photodetectors generates correction signals. Instrument detects Doppler shifts in radar and corrects processing parameters so ambiguities caused by shifts not manifested as double or overlapping images.

  7. Calculation of the Doppler broadening function using Fourier analysis

    International Nuclear Information System (INIS)

    An efficient and precise method for calculation of Doppler broadening function is very important to obtain average group microscopic cross sections, self shielding factors, resonance integrals and others reactor physics parameter. In this thesis two different methods for calculation of Doppler broadening function and interference term will be presented. The main method is based on a new integral form for Doppler broadening function ?(x,?) which gives a mathematical interpretation of the approximation proposed by Bethe and Placzek, as the convolution of the Lorentzian function with a Gaussian function. This interpretation besides leading to a new integral form for ?(x,?), enables to obtain a simple analytic solution for the Doppler broadening function. (author)

  8. Burst Format Design for Optimum Joint Estimation of Doppler-Shift and Doppler-Rate in Packet Satellite Communications

    Directory of Open Access Journals (Sweden)

    Luca Giugno

    2007-05-01

    Full Text Available This paper considers the problem of optimizing the burst format of packet transmission to perform enhanced-accuracy estimation of Doppler-shift and Doppler-rate of the carrier of the received signal, due to relative motion between the transmitter and the receiver. Two novel burst formats that minimize the Doppler-shift and the Doppler-rate Cramér-Rao bounds (CRBs for the joint estimation of carrier phase/Doppler-shift and of the Doppler-rate are derived, and a data-aided (DA estimation algorithm suitable for each optimal burst format is presented. Performance of the newly derived estimators is evaluated by analysis and by simulation, showing that such algorithms attain their relevant CRBs with very low complexity, so that they can be directly embedded into new-generation digital modems for satellite communications at low SNR.

  9. Respiratory effort energy estimation using Doppler radar.

    Science.gov (United States)

    Shahhaidar, Ehsaneh; Yavari, Ehsan; Young, Jared; Boric-Lubecke, Olga; Stickley, Cris

    2012-01-01

    Human respiratory effort can be harvested to power wearable biosensors and mobile electronic devices. The very first step toward designing a harvester is to estimate available energy and power. This paper describes an estimation of the available power and energy due to the movements of the torso during breathing, using Doppler radar by detecting breathing rate, torso displacement, torso movement velocity and acceleration along the sagittal movement of the torso. The accuracy of the detected variables is verified by two reference methods. The experimental result obtained from a healthy female human subject shows that the available power from circumferential movement can be higher than the power from the sagittal movement. PMID:23365993

  10. Moessbauer spectroscopy - applications of the Doppler principle

    International Nuclear Information System (INIS)

    Moessbauer spectroscopy is an experimental method based on the application of the Doppler principle in the velocity modulation system for variation of ?-ray energy. The object of observations is a resonating nucleus. From Moessbauer spectra one can gain information on the electronic and magnetic environment (based on hyperfine interactions) and on the vibrational states of atoms (based on the Debey-Waller factor). It is a typical microscopic method which has found applications in all disciplines of natural sciences as well as in medicine, art, archaeology and materials science. (author) 5 figs., 37 refs

  11. [Transvaginal color Doppler in ovarian neoplasms].

    Science.gov (United States)

    Martínez, J; Vaccaro, H; Amor, F; Gana, J A; González, E

    1993-01-01

    Thirty one patients with clinical and sonographic diagnosis of ovarian tumor were studied prospectively, with Transvaginal Color Doppler. There were 24 benign and 7 malignant tumors (4 stage I borderline, I stage IA cistoadenocarcinoma and 2 adenocarcinoma stage III). Six malignant tumors had resistance indexes (IR) from 0.17 to 0.55. In one borderline no vascular signal was obtained. The probability of malignancy increased inversely with the IR from 60%, with RI below 0.60 to 100% with IR below 0.4. PMID:7991859

  12. An improved instantaneous laser Doppler velocity system

    Science.gov (United States)

    Desio, Charles V.; Olcmen, Semih; Schinetsky, Philip

    2016-02-01

    In this paper, improvements made on a single velocity component instantaneous laser Doppler velocimetry (ILDV) system are detailed. The ILDV system developed in this research effort is capable of measuring a single velocity component at a rate as high as two megahertz. The current system accounts for the effects of the laser intensity variation on the measured velocity and eliminates the use of a Pockels cell used in previous ILDV systems. The system developed in the current effort was tested using compressible, subsonic jet flows. The ILDV system developed would be most beneficial where a high data capture rate is needed such as in shock tubes, and high-speed wind tunnels.

  13. Transmission media effects on precise Doppler tracking

    Science.gov (United States)

    Callahan, P. S.

    1978-01-01

    The effects of the transmission media - the earth's troposphere and ionosphere, and the solar wind - on precise Doppler tracking are discussed. The charged particle effects can be largely removed by dual frequency observations; however there are limitations to these corrections (besides system noise and/or finite integration times) including the effects of magnetic fields, diffraction, and differential refraction, all of which must be carefully evaluated. The earth's troposphere can contribute an error of delta f/f approximately 10 to the minus 14th power.

  14. Observation of sub-Doppler absorption in the /Lambda-type three-level Doppler-broadened cesium system

    OpenAIRE

    Wang, Junmin; Wang, Yanhua; Yan, Shubin; Liu, Tao; Zhang, Tiancai

    2003-01-01

    Thanks to the atomic coherence in coupling laser driven atomic system, sub-Doppler absorption has been observed in Doppler-broadened cesium vapor cell via the /Lambda-type three-level scheme. The linewidth of the sub-Doppler absorption peak become narrower while the frequency detuning of coupling laser increases. The results are in agreement with the theoretical prediction by G. Vemuri et al.[PRA,Vol.53(1996) p.2842].

  15. Doppler ultrasound scan during normal gestation: umbilical circulation; Ecografia Doppler en la gestacion normal: circulacion umbilical

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz, T.; Sabate, J.; Martinez-Benavides, M. M.; Sanchez-Ramos, J. [Hospital Virgen Macarena. Sevilla (Spain)

    2002-07-01

    To determine normal umbilical circulation patterns by means of Doppler ultrasound scan in a healthy gestating population without risk factors and with normal perinatal results, and to evaluate any occurring modifications relative to gestational age by obtaining records kept during pregnancy. One hundred and sixteen pregnant women carrying a single fetus have been studied. These women had no risk factors, with both clinical and analytical controls, as well as ultrasound scans, all being normal. There were performed a total of 193 Doppler ultrasound scans between weeks 15 and 41 of gestation, with blood-flow analysis in the arteries and vein of the umbilical cord. The obtained information was correlated with parameters that evaluate fetal well-being (fetal monitoring and/or oxytocin test) and perinatal result (delivery type, birth weight, Apgar score). Statistical analysis was performed with the programs SPSS 6.0.1 for Windows and EPIINFO 6.0.4. With pulsed Doppler, the umbilical artery in all cases demonstrated a biphasic morphology with systolic and diastolic components and without retrograde blood flow. As the gestation period increased, there was observed a progressive decrease in resistance along with an increase in blood-flow velocity during the diastolic phase. The Doppler ultrasound scan is a non-invasive method that permits the hemodynamic study of umbilical blood circulation. A knowledge of normal blood-flow signal morphology, as well as of the normal values for Doppler indices in relation to gestational age would permit us to utilize this method in high-risk pregnancies. (Author) 30 refs.

  16. Fusion of Telescopic and Doppler Radar Data

    Science.gov (United States)

    Navara, M.; Matousek, M.; Drbohlav, O.

    2014-09-01

    We study the possibilities of observations of satellites at circular LEO orbits simultaneously by a telescope and a bistatic continuous-wave Doppler radar. Telescopic images allow for trajectory determination except for its distance (and hence height). Assuming a circular orbit, the height can be computed from the angular speed, but this is often impossible for LEO objects which do not remain in the field of view during the whole exposure time. To restore the missing information, we use Doppler radar data from a radio astronomy network, originally designed for detection of meteors. Using simulated perturbations of real radar data we studied their influence on the estimates of (i) permanent parameters of trajectory (orbital elements), (ii) instantaneous parameters of trajectory, (iii) distance and height estimates if the other parameters are given by the telescopic data. We derived recommendations for the optimal positions of the transmitter and receivers leading to the best resolution. We also discuss possible ways of improvement of this technique. Fusion results are shown on a suite of several matched radar and telescopic satellite fly-over data.

  17. Color doppler imaging of hepatic tumors

    International Nuclear Information System (INIS)

    To evaluate the color Doppler imaging patterns of hepatoma, hemangioma, and metastasis. The study comprised 37 patients with liver mass lesions: 12 patients had hepatoma, 15 had hemangiomas and 10 had metastatic liver cancers. All 37, who showed hepatic mass on gray scale ultrasonogrphy, were analyzed prospectively. Color mapping of tumors was performed for these patients, and the fastest or next fastest vessel was spectrally analysed to show blood pattern and to measure peak velocity. In all the 12 patients with hepatoma, spectral analysis revealed exteusive pulsating arterial blood flow within the tumor;peak velocities were 7?65cm/sec(mean 34cm/sec). In ten hemangiomas(66%) color mapping revealed blood flow within the tumor and spectral analysis revealed this possibility in eight of the ten tumors. In none of these patients was a pulsating continous wave observed; peak velocity was 5?21cm/sec (mean 12.8cm/sec). In no mestastatic tumors was blood flow observed. Color Doppler imaging is helpful in the differentiation of hepatoma, hemangioma, and metastatic tumor in the liver

  18. Windowed multipole for cross section Doppler broadening

    Science.gov (United States)

    Josey, C.; Ducru, P.; Forget, B.; Smith, K.

    2016-02-01

    This paper presents an in-depth analysis on the accuracy and performance of the windowed multipole Doppler broadening method. The basic theory behind cross section data is described, along with the basic multipole formalism followed by the approximations leading to windowed multipole method and the algorithm used to efficiently evaluate Doppler broadened cross sections. The method is tested by simulating the BEAVRS benchmark with a windowed multipole library composed of 70 nuclides. Accuracy of the method is demonstrated on a single assembly case where total neutron production rates and 238U capture rates compare within 0.1% to ACE format files at the same temperature. With regards to performance, clock cycle counts and cache misses were measured for single temperature ACE table lookup and for windowed multipole. The windowed multipole method was found to require 39.6% more clock cycles to evaluate, translating to a 7.9% performance loss overall. However, the algorithm has significantly better last-level cache performance, with 3 fewer misses per evaluation, or a 65% reduction in last-level misses. This is due to the small memory footprint of the windowed multipole method and better memory access pattern of the algorithm.

  19. Color Doppler Ultrasonographic Features of Hashimoto's Thyroiditis

    International Nuclear Information System (INIS)

    Color Doppler ultrasonographic(US) features of 28 patients with Hashimato's thyroiditis were evaluated with regard to echo and color-flow patterns. Correlation of color-flow pattern with thyroid function was performed. All 28 patients showed varying degrees of diffuse enlargement of the thyroid gland and a heterogeneous echo pattern.Color-flow pattern of increased blood flow. Low to moderate, focally increased blood flow was seen in 26 patients(92.8%). Of these 26 patients, 24 patients showed subclinical hypothyroidism or euthyroidism. Two patients who showed hyperthyroidism showed several pieces of focally increased color flow, Which was noted during both systole and diastole. Diffuse, multifocal color-flow throughout thyroid gland was seen in two patients with Hashimato's thyroiditis: one with clinical hypothyroidism and the other with subclinical hypothyroidism. Even though Hashimoto's thyroiditis showed variable color-flow patterns, we believe that heterogenous parenchymal echopattern with low or moderately increased flow is a rather characteristic feature of Hashimoto's thyroiditis, and we suggest that color Doppler US provides additional information for evaluation of Hashimoto's thyroiditis

  20. The Doppler Wind and Temperature Sounder

    Science.gov (United States)

    McHugh, Martin; Fritts, Dave; Gordley, Larry

    2014-06-01

    The Doppler Wind and Temperature Sounder (DWTS) is novel sensor concept for measuring global winds and temperatures from cloud-top to the thermosphere. This will significantly improve medium- and long-range weather forecasts and enable more advanced tracking of severe storms. The approach uses the inherent high spectral resolution from gas filter correlation radiometry to simultaneously measure the Doppler shift and linewidth of limb emission spectra as viewed from low-Earth orbit. DWTS images the limb through low-pressure gas cells containing CO2, NO and NO2. We describe here how very accurate vector winds and kinetic temperatures can be inferred from these observations. Profiles of temperature and wind can be measured day and night continuously from 15 to over 250 km at intervals of 10 km along-track with less than 2% uncertainty. A constellation of 6-12 DWTS instruments on small satellites would provide unprecedented observations of global atmospheric dynamics from the lower stratosphere into the middle thermosphere, greatly improving weather and storm forecasting. We present the current status and plans to realize this important mission.

  1. Doppler peaks a fingerprint of topological defects

    CERN Document Server

    Durrer, R; Sakellariadou, M; Durrer, Ruth; Gangui, Alejandro; Sakellariadou, Mairi

    1995-01-01

    The fluctuations in the cosmic microwave background (CMB) on large angular scales (> few degrees) are caused by perturbations in the gravitational field via the Sachs--Wolfe effect. On intermediate scales, 0.1^\\circ\\lsim\\theta\\lsim 2^\\circ, the dominant contribution is due to coherent oscillations in the baryon radiation plasma before recombination. Unless the universe is reionized at some redshift z>50, these oscillations lead to the `Doppler peaks' in the angular power spectrum. In structure formation scenarios based on inflation the position of the first peak is typically at \\ell\\sim 200, with a height which is 4 -- 6 times that of the Sachs--Wolfe `plateau'. Here we present a corresponding study for perturbations induced by global textures. We find that the first Doppler peak is reduced to an amplitude comparable to that of the Sachs--Wolfe contribution, and that it is shifted to \\ell\\sim 350. We believe that our analysis can be easily extended to other types of global topological defects and general glob...

  2. CAMEX-4 ER-2 DOPPLER RADAR V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The ER-2 Doppler radar (EDOP) is an X-band (9.6 GHz) Doppler radar mounted in the nose of ER-2. The instrument has two fixed antennas, one pointing at nadir and the...

  3. The Doppler and gravitational components of the cosmological redshift

    International Nuclear Information System (INIS)

    We decompose the cosmological redshift in the standard Friedmann cosmologies into two shifts: a Doppler shift attributable to the recession of the galaxies, and a gravitational shift attributable to the curvature of the universe. For galaxies nearby enough for their recessional motion to be non-relativistic, we interpret our results for the Doppler and gravitational shifts with the aid of Birkhoff's theorem. (author)

  4. Musculoskeletal colour/power Doppler in sports medicine

    DEFF Research Database (Denmark)

    Boesen, M I; Boesen, M; Langberg, Henning; Koenig, M J; Boesen, A; Bliddal, H; Torp-Pedersen, S

    2010-01-01

    This review article discusses the aspects of sports medicine where musculoskeletal Doppler ultrasound has valuable contribution in diagnosis and/or treatment of some of the typical musculoskeletal sports injuries. Also, conditions where the Doppler ultrasound has no value are discussed. Some...

  5. Micro-Doppler classification of riders and riderless horses

    Science.gov (United States)

    Tahmoush, David

    2014-05-01

    Micro-range Micro-Doppler can be used to isolate particular parts of the radar signature, and in this case we demonstrate the differences in the signature between a walking horse versus a walking horse with a rider. Using micro-range micro-Doppler, we can distinguish the radar returns from the rider as separate from the radar returns of the horse.

  6. CAMEX-4 ER-2 DOPPLER RADAR V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The ER-2 Doppler radar (EDOP) is an X-band (9.6 GHz) Doppler radar mounted in the nose of ER-2. The instrument has two fixed antennas, one pointing at nadir and the...

  7. Diagnosis of aortic dissection by color-coded doppler

    International Nuclear Information System (INIS)

    Using a new ultrasound technique, the Color-Coded Doppler Echocardiography, the thoracic extension of a previously diagnosed dissecting aneurysm of the abdominal aorta was detected in an asymptomatic patient. The Color-Coded Doppler seems to be a reliable method in diagnosing aortic dissecting aneurysm and the technique of choice for the follow-up of the chronic forms of disease

  8. "An analysis of the classical Doppler Effect"[1] revisited

    OpenAIRE

    Rothenstein, Bernhard; Nafornita, Corina

    2004-01-01

    After having shown that the formula which describes the Doppler effect in the general case holds only in the case of the "very high" frequency assumption, we derive free of assumptions Doppler formulas for two scenarios presented in the revisited paper.

  9. Cervicocranial artery dissection. Detection by Doppler ultrasound and MR angiography

    International Nuclear Information System (INIS)

    Purpose: To evaluate pulsed Doppler ultrasound and MR angiography (MRA) in the diagnosis of cervicocranial dissection. Material and Methods: Fourteen patients with cervicocranial artery dissection were examined over a 3-year period. Twelve patients had dissection of the extracranial part of the internal carotid artery, and 2 had vertebral artery dissection. All patients were examined with pulsed Doppler ultrasound. In addition, all patients had conventional angiography (n=9) and/or MR imaging including MRA (n=9). Results: Doppler ultrasound disclosed unspecific abnormalities in 11 of 14 dissected vessels; 3 patients had false-negative Doppler findings. MRA showed vessel abnormalities in 9 of 9 patients; 2 vessels were occluded, and 7 vessels had changes typical of dissection (double lumen and/or string sign). Twelve patients had follow-up examinations with pulsed Doppler ultrasound (n=12), conventional angiography (n=3), and MRA/MR (n=11). Follow-up Doppler showed complete or partial normalization in 6 of 9 patients, all confirmed by either angiography or MRA. Conclusion: Our findings suggest that Doppler ultrasound may be used in follow-up of pathologic Doppler findings in known dissections, and that MRA may replace angiography in the confirmative diagnosis of cervicocranial dissection. (orig.)

  10. Ionospheric Doppler measurements by means of HF-radar techniques

    Directory of Open Access Journals (Sweden)

    D. Altadill

    2005-06-01

    Full Text Available Studies of the dynamics of the ionosphere and its related phenomena are mainly based on Doppler Drift measurements. The time variation (ionisation/recombination of plasma density, thermospheric wind and others can be observed by means of HF-radars. The technique of Doppler Drift measurements is a quite complex technique that is now affordable by means of an advanced ionospheric sounder. The combination of vertical sounding and interferometric Doppler detection discloses the Doppler sources. The echo signal contains the Doppler shift in frequency imposed on the wave carrier by each point source where the signal is reflected. Other phenomena like environmental noise and the intrinsic error of the measurements that, together with the change in time of the refractive index, affect the measurements in various ways impeding to better quantify the results.

  11. One way Doppler extractor. Volume 1: Vernier technique

    Science.gov (United States)

    Blasco, R. W.; Klein, S.; Nossen, E. J.; Starner, E. R.; Yanosov, J. A.

    1974-01-01

    A feasibility analysis, trade-offs, and implementation for a One Way Doppler Extraction system are discussed. A Doppler error analysis shows that quantization error is a primary source of Doppler measurement error. Several competing extraction techniques are compared and a Vernier technique is developed which obtains high Doppler resolution with low speed logic. Parameter trade-offs and sensitivities for the Vernier technique are analyzed, leading to a hardware design configuration. A detailed design, operation, and performance evaluation of the resulting breadboard model is presented which verifies the theoretical performance predictions. Performance tests have verified that the breadboard is capable of extracting Doppler, on an S-band signal, to an accuracy of less than 0.02 Hertz for a one second averaging period. This corresponds to a range rate error of no more than 3 millimeters per second.

  12. Analysis of Doppler effect with JAERI-Fast set

    International Nuclear Information System (INIS)

    Temperature dependence of group cross sections in the JAERI-Fast set versions I, IR, II and IIR has been tested from the analysis of Doppler experiments performed with two different methods. One is Doppler reactivity measurement for the whole core of SEFOR assembly, and the other sample Doppler reactivity measurement for natural UO2 in FCA assemblies V-1, V-2, VI-1 and VI-2, ZPR-6-7, ZPR-3-47, and ZPPR-2 and 3. Doppler effects were calculated with one- and two-dimensional diffusion 1-st order perturbation code DOPP2D. The results calculated with the JAERI-Fast set versions II and IIR are in good agreement with the experimental ones. In these calculation, resonance heterogeneity effect, stainless-stell buffer effect and plate heterogeneity effect are considered, and these effects contribute significantly to Doppler effect. (auth.)

  13. Use of GPS network data for HF Doppler measurements interpretation

    CERN Document Server

    Petrova, Inna R; Latypov, Ruslan R

    2014-01-01

    The method of measurement of Doppler frequency shift of ionospheric signal - HF Doppler technique - is one of well-known and widely used methods of ionosphere research. It allows to research various disturbances in the ionosphere. There are some sources of disturbances in the ionosphere. These are geomagnetic storms, solar flashes, metrological effects, atmospheric waves. This method allows to find out the influence of earthquakes, explosions and other processes on the ionosphere, which occur near to the Earth. HF Doppler technique has the high sensitivity to small frequency variations and the high time resolution, but interpretation of results is difficult. In this work we make an attempt to use GPS data for Doppler measurements interpretation. Modeling of Doppler frequency shift variations with use of TEC allows to separate ionosphere disturbances of medium scale.

  14. Avaliação dos tumores hepáticos ao Doppler Doppler evaluation of liver tumors

    Directory of Open Access Journals (Sweden)

    Márcio Martins Machado

    2004-10-01

    Full Text Available Os avanços recentes na ultra-sonografia têm ampliado a possibilidade de detecção de tumores hepáticos. Isto tem auxiliado na perspectiva de melhora do prognóstico destes pacientes, à medida que novas técnicas terapêuticas têm surgido. Neste artigo os autores relatam achados ao Doppler que podem auxiliar na identificação e caracterização dos tumores hepáticos, avaliando dados do Doppler colorido, pulsado e do Doppler de amplitude ("power Doppler". Fazem, também, referência a novas modalidades de imagem, como o uso da harmônica.Recent advances in ultrasound have optimized the detection of liver tumors and helped to improve the prognosis of patients with this condition as newly developed and improved therapeutic modalities have been established. The authors review important Doppler findings which may help in the identification and characterization of some hepatic tumors through the evaluation of color Doppler, pulsed Doppler and power Doppler features. New imaging methods such as the use of harmonics imaging are also reviewed.

  15. The recondite intricacies of Zeeman Doppler mapping

    CERN Document Server

    Stift, M J; Cowley, C R

    2011-01-01

    We present a detailed analysis of the reliability of abundance and magnetic maps of Ap stars obtained by Zeeman Doppler mapping (ZDM). It is shown how they can be adversely affected by the assumption of a mean stellar atmosphere instead of appropriate "local" atmospheres corresponding to the actual abundances in a given region. The essenceof the difficulties was already shown by Chandrasekhar's picket-fence model. The results obtained with a suite of Stokes codes written in the Ada programming language and based on modern line-blanketed atmospheres are described in detail. We demonstrate that the high metallicity values claimed to have been found in chemically inhomogeneous Ap star atmospheres would lead to local temperature structures, continuum and line intensities, and line shapes that differ significantly from those predicted by a mean stellar atmosphere. Unfortunately, past applications of ZDM have consistently overlooked the intricate aspects of metallicity with their all-pervading effects. The erroneou...

  16. DC coupled Doppler radar physiological monitor.

    Science.gov (United States)

    Zhao, Xi; Song, Chenyan; Lubecke, Victor; Boric-Lubecke, Olga

    2011-01-01

    One of the challenges in Doppler radar systems for physiological monitoring is a large DC offset in baseband outputs. Typically, AC coupling is used to eliminate this DC offset. Since the physiological signals of interest include frequency content near DC, it is not desirable to simply use AC coupling on the radar outputs. While AC coupling effectively removes DC offset, it also introduces a large time delay and distortion. This paper presents the first DC coupled IQ demodulator printed circuit board (PCB) design and measurements. The DC coupling is achieved by using a mixer with high LO to RF port isolation, resulting in a very low radar DC offset on the order of mV. The DC coupled signals from the PCB radar system were successfully detected with significant LNA gain without saturation. Compared to the AC coupled results, the DC coupled results show great advantages of less signal distortion and more accurate rate estimation. PMID:22254704

  17. Implementation of Doppler backscattering for MAST

    CERN Document Server

    Hillesheim, J C; Peebles, W A; Meyer, H; Meakins, A; Field, A R; Dunai, D; Carr, M; Hawkes, N

    2014-01-01

    A sixteen channel millimeter-wave diagnostic system, covering the frequency range 30-75 GHz, has been installed on MAST [B. Lloyd et al., Nucl. Fusion 43, 1665 (2003)] and has been successfully used for both Doppler backscattering (DBS) and conventional (normal-incidence) fluctuation reflectometry. DBS has become a well-established and versatile diagnostic technique for the measurement of intermediate- k ($k_{\\bot} \\rho_i \\sim 1$, and higher) density fluctuations and flows in magnetically confined fusion experiments. The $180^{\\circ}$ backscattering for DBS requires three dimensional wave-vector matching between the launched beam and the plasma fluctuations inducing the scattering, which are expected to be highly elongated along the magnetic field. The large pitch angle in MAST means that DBS implementation depends strongly on the capability to accurately launch the probing beam at a toroidal and poloidal angle that is matched to the magnetic field at the scattering location. We report on the scattering consi...

  18. Phase Doppler Anemometry as an Ejecta Diagnostic

    Science.gov (United States)

    Bell, David; Chapman, David

    2015-06-01

    When a shock wave is incident on a free surface, micron sized pieces of the material can be ejected from the surface. Phase Doppler Anemometry (PDA) is being developed to simultaneously measure the size and velocity of the individual shock induced ejecta particles. The measurements will provide an insight into ejecta phenomena. The results from experiments performed on the 13 mm bore light gas gun at the Institute of Shock Physics, Imperial College London are presented. Specially grooved tin targets were shocked at pressures of up to 14 GPa, below the melt on release pressure, to generate ejecta particles. The experiments are the first time that PDA has been successfully fielded on dynamic ejecta experiments. The results and the current state of the art of the technique are discussed along with the future improvements required to further improve performance and increase usability.

  19. Position finding using simple Doppler sensors

    Directory of Open Access Journals (Sweden)

    S. Schelkshorn

    2007-06-01

    Full Text Available An increasing number of modern applications and services is based on the knowledge of the users actual position. Depending on the application a rough position estimate is sufficient, e. g. services in cellular networks that use the information about the users actual cell. Other applications, e. g. navigation systems use the GPS-System for accurate position finding. Beyond these outdoor applications a growing number of indoor applications requires position information. The previously mentioned methods for position finding (mobile cell, GPS are not usable for these indoor applications.

    Within this paper we will present a system that relies on the simultaneous measurement of doppler signals at four different positions to obtain position and velocity of an unknown object. It is therefore suiteable for indoor usage, extendig already existing wireless infrastructure.

  20. Quadrature detection of a Doppler signal.

    Science.gov (United States)

    Hogenboom, D O; Dimarzio, C A

    1998-05-01

    We have employed a quadrature detection technique to measure theDoppler signal from a moving target. We mix a circularly polarizedreference with a linearly polarized signal to produce an output thatcontains the real and the imaginary parts of the interference field inthe two output polarizations. We are thus able to measure thein-phase and the quadrature components of an interferometric signalsimultaneously by splitting the output with a polarizing beamsplitter. We present data that demonstrate our ability through thistechnique to obtain both the amplitude and the frequency of vibrationof an audio speaker. We also demonstrate the technique's abilityto give one access to the direction of motion and instantaneousposition of the target. PMID:18273194

  1. LISA data analysis; 1, Doppler demodulation

    CERN Document Server

    Cornish, N; Cornish, Neil; Larson, Shane

    2003-01-01

    The orbital motion of the Laser Interferometer Space Antenna (LISA) produces amplitude, phase and frequency modulation of a gravitational wave signal. The modulations have the effect of spreading a monochromatic gravitational wave signal across a range of frequencies. The modulations encode useful information about the source location and orientation, but they also have the deleterious affect of spreading a signal across a wide bandwidth, thereby reducing the strength of the signal relative to the instrument noise. We describe a simple method for removing the dominant, Doppler, component of the signal modulation. The demodulation reassembles the power from a monochromatic source into a narrow spike, and provides a quick way to determine the sky locations and frequencies of the brightest gravitational wave sources.

  2. Transcranial doppler, EEG and SEP monitoring

    Directory of Open Access Journals (Sweden)

    A. Opp

    2009-07-01

    Full Text Available The role of neuromonitoring in the prevention of cerebral damage associated with cardiosurgical interventions has not yet been clearly elucidated. Reliable randomised studies from evidence-based medicine showing a clear reduction of risk do not exist. Numerous studies and reviews however, have confirmed that non-invasive procedures for monitoring neuronal or neurophysiological changes before, during and after interventions within the heart or the major thoracic vessels are available and provide early indications of damage.Technological modalities and clinical indications for non invasive cerebral monitoring were evaluated:Electroencephalography (EEG with processed EEG, bispectral index (BIS and the evoked potential for use with spinal cord functionNear infrared spectroscopy (NIRS for assessment of cerebral perfusion and oxygenationTranscranial Doppler sonography (TCDS for assessment of cerebral circulation and perfusionMultimodality monitoring as a combination of EEG, NIRS and TCDS.

  3. Microscale Heat Conduction Models and Doppler Feedback

    Energy Technology Data Exchange (ETDEWEB)

    Hawari, Ayman I.; Ougouag, Abderrafi

    2015-01-22

    The objective of this project is to establish an approach for providing the fundamental input that is needed to estimate the magnitude and time- dependence of the Doppler feedback mechanism in Very High Temperature reactors. This mechanism is the foremost contributor to the passive safety of gas-cooled, graphite-moderated high temperature reactors that use fuel based on Tristructural-Isotropic (TRISO) coated particles. Therefore, its correct prediction is essential to the conduct of safety analyses for these reactors. Since the effect is directly dependent on the actual temperature reached by the fuel during transients, the underlying phenomena of heat deposition, heat transfer and temperature rise must be correctly predicted. To achieve the above objective, this project will explore an approach that accounts for lattice effects as well as local temperature variations and the correct definition of temperature and related local effects.

  4. Widefield laser doppler velocimeter: development and theory.

    Energy Technology Data Exchange (ETDEWEB)

    Hansche, Bruce David; Reu, Phillip L.; Massad, Jordan Elias

    2007-03-01

    The widefield laser Doppler velocimeter is a new measurement technique that significantly expands the functionality of a traditional scanning system. This new technique allows full-field velocity measurements without scanning, a drawback of traditional measurement techniques. This is particularly important for tests in which the sample is destroyed or the motion of the sample is non-repetitive. The goal of creating ''velocity movies'' was accomplished during the research, and this report describes the current functionality and operation of the system. The mathematical underpinnings and system setup are thoroughly described. Two prototype experiments are then presented to show the practical use of the current system. Details of the corresponding hardware used to collect the data and the associated software to analyze the data are presented.

  5. Wind Field Measurements With Airborne Doppler Lidar

    Science.gov (United States)

    Menzies, Robert T.

    1999-01-01

    In collaboration with lidar atmospheric remote sensing groups at NASA Marshall Space Flight Center and National Oceanic and Atmospheric Administration (NOAA) Environmental Technology Laboratory, we have developed and flown the Multi-center Airborne Coherent Atmospheric Wind Sensor (MACAWS) lidar on the NASA DC-8 research aircraft. The scientific motivations for this effort are: to obtain measurements of subgrid scale (i.e. 2-200 km) processes and features which may be used to improve parameterizations in global/regional-scale models; to improve understanding and predictive capabilities on the mesoscale; and to assess the performance of Earth-orbiting Doppler lidar for global tropospheric wind measurements. MACAWS is a scanning Doppler lidar using a pulsed transmitter and coherent detection; the use of the scanner allows 3-D wind fields to be produced from the data. The instrument can also be radiometrically calibrated and used to study aerosol, cloud, and surface scattering characteristics at the lidar wavelength in the thermal infrared. MACAWS was used to study surface winds off the California coast near Point Arena, with an example depicted in the figure below. The northerly flow here is due to the Pacific subtropical high. The coastal topography interacts with the northerly flow in the marine inversion layer, and when the flow passes a cape or point that juts into the winds, structures called "hydraulic expansion fans" are observed. These are marked by strong variation along the vertical and cross-shore directions. The plots below show three horizontal slices at different heights above sea level (ASL). Bottom plots are enlargements of the area marked by dotted boxes above. The terrain contours are in 200-m increments, with the white spots being above 600-m elevation. Additional information is contained in the original.

  6. Clutter reduction using Doppler sonar in a harbor environment.

    Science.gov (United States)

    Yang, T C; Schindall, J; Huang, Chen-Fen; Liu, Jin-Yuan

    2012-11-01

    A high frequency experiment was conducted in the Woods Hole Harbor in Massachusetts to evaluate the effectiveness of Doppler sonar for discriminating targets from reverberation. Using a pulsed linear frequency modulated signal, one finds that the matched filtered outputs are filled with high-level discrete backscattered returns, referred to as clutter, which are often confused with the target echo. The high level non-target returns have an amplitude distribution that is heavy-tailed. Using a Doppler-sensitive binary-phase-shift-keying signal coded with an m-sequence, the target echo and clutter can be separated by Doppler and delay, and tracked using the Doppler spectrogram (Dopplergram). The Doppler filtered time series show a background reverberation with a Rayleigh-like amplitude distribution, with an improved signal-to-(peak) reverberation ratio compared with that without Doppler filtering. The reduced reverberation level with Doppler processing decreases the probability of false alarm (Pfa) for a given threshold level. Conversely, for a given Pfa, the higher signal-to-(peak) reverberation ratio implies a higher probability of detection. Transmission loss measurement was conducted to estimate some of the system parameters, e.g., the source level and target strength relative to the noise level. PMID:23145591

  7. [The use of Doppler in the second half of pregnancy].

    Science.gov (United States)

    Komacki, Jakub; Skrzypczak, Jana

    2015-08-01

    The article is a review of the literature on the use and clinical applicability of Doppler examination in the second half of pregnancy Nowadays, despite its accessibility Doppler ultrasound in pregnancy is often contraindicated. At the same time, the is no evidence of clinical utility of Doppler studies in a low-risk pregnancy The main indications for Doppler examinations in pregnancy include intrauterine growth restriction (IUGR), suspicion of fetal anemia, and complications of monochorionic twin pregnancy As far as IUGR is concerned, Doppler allows to diagnose IUGR associated with placental insufficiency and to differentiate IUGR from small for gestational age fetuses (SGA). Doppler is also very useful in making the decision about the time of delivery of IUGR fetuses. The assessment of the peak systolic velocity in the middle cerebral artery (PSV-MVA) reduced the rate of invasive procedures due to fetal anemia by approximately 70%. Complications of the second half of pregnancy which are indications for Doppler ultrasound include selective IUGR, TTTS and TAPS. Similarly to the first trimester, the mid-trimester assessment of the blood flow in the uterine arteries plays an important role in the prediction of preeclampsia and IUGR, especially early-onset forms of these complications. PMID:26492713

  8. Pulsed Doppler echocardiographic analysis of mitral regurgitation after myocardial infarction.

    Science.gov (United States)

    Loperfido, F; Biasucci, L M; Pennestri, F; Laurenzi, F; Gimigliano, F; Vigna, C; Rossi, E; Favuzzi, A; Santarelli, P; Manzoli, U

    1986-10-01

    In 72 patients with previous myocardial infarction (MI), mitral regurgitation (MR) was assessed by pulsed-wave Doppler echocardiography and compared with physical and 2-dimensional echocardiographic findings. MR was found by Doppler in 29 of 42 patients (62%) with anterior MI, 11 of 30 (37%) with inferior MI (p less than 0.01) and in none of 20 normal control subjects. MR was more frequent in patients who underwent Doppler study 3 months after MI than in those who underwent Doppler at discharge (anterior MI = 83% vs 50%, p less than 0.01; inferior MI = 47% vs 27%, p = not significant). Of 15 patients who underwent Doppler studies both times, 3 (all with anterior MI) had MR only on the second study. Of the patients with Doppler MR, 12 of 27 (44%) with a left ventricular (LV) ejection fraction (EF) greater than 30% and 1 of 13 (8%) with an EF of 30% or less (p less than 0.01) had an MR systolic murmur. Mitral prolapse or eversion and papillary muscle fibrosis were infrequent in MI patients, whether or not Doppler MR was present. The degree of Doppler MR correlated with EF (r = -0.61), LV systolic volume (r = 0.47), and systolic and diastolic mitral anulus circumference (r = 0.52 and 0.51, respectively). Doppler MR was present in 24 of 28 patients (86%) with an EF of 40% or less and in 16 of 44 (36%) with EF more than 40% (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3766410

  9. Sub-Doppler laser cooling of potassium atoms

    OpenAIRE

    Landini, M.; Roy, S.; L. Carcagn\\xec; Trypogeorgos, D.; Fattori, M.; Inguscio, M.; Modugno, G.

    2011-01-01

    We investigate sub-Doppler laser cooling of bosonic potassium isotopes, whose small hyperfine splitting has so far prevented cooling below the Doppler temperature. We find instead that the combination of a dark optical molasses scheme that naturally arises in this kind of systems and an adiabatic ramping of the laser parameters allows to reach sub-Doppler temperatures for small laser detunings. We demonstrate temperatures as low as 25(3)microK and 47(5)microK in high-density...

  10. Sub-Doppler laser cooling of potassium atoms

    Energy Technology Data Exchange (ETDEWEB)

    Landini, M. [LENS and Dipartimento di Fisica e Astronomia, Universita di Firenze, I-50019 Sesto Fiorentino (Italy); INFN, Sezione di Firenze, I-50019 Sesto Fiorentino (Italy); Dipartimento di fisica, Universita di Trento, I-38123 Povo (Trento) (Italy); Roy, S.; Carcagni, L.; Trypogeorgos, D. [LENS and Dipartimento di Fisica e Astronomia, Universita di Firenze, I-50019 Sesto Fiorentino (Italy); Fattori, M.; Inguscio, M.; Modugno, G. [LENS and Dipartimento di Fisica e Astronomia, Universita di Firenze, I-50019 Sesto Fiorentino (Italy); INFN, Sezione di Firenze, I-50019 Sesto Fiorentino (Italy)

    2011-10-15

    We investigate the sub-Doppler laser cooling of bosonic potassium isotopes, whose small hyperfine splitting has so far prevented cooling below the Doppler temperature. We find instead that the combination of a dark optical molasses scheme that naturally arises in this kind of system and an adiabatic ramping of the laser parameters allows us to reach sub-Doppler temperatures for small laser detunings. We demonstrate temperatures as low as 25{+-}3 {mu}K and 47{+-}5 {mu}K in high-density samples of the two isotopes {sup 39}K and {sup 41}K, respectively. Our findings should find application to other atomic systems.

  11. Sub-Doppler laser cooling of potassium atoms

    CERN Document Server

    Landini, M; Carcagni', L; Trypogeorgos, D; Fattori, M; Inguscio, M; Modugno, G

    2011-01-01

    We investigate sub-Doppler laser cooling of bosonic potassium isotopes, whose small hyperfine splitting has so far prevented cooling below the Doppler temperature. We find instead that the combination of a dark optical molasses scheme that naturally arises in this kind of systems and an adiabatic ramping of the laser parameters allows to reach sub-Doppler temperatures for small laser detunings. We demonstrate temperatures as low as 25(3)microK and 47(5)microK in high-density samples of the two isotopes 39K and 41K, respectively. Our findings will find application to other atomic systems.

  12. Rotational Doppler Effect: A Probe for Molecular Orbitals Anisotropy.

    Science.gov (United States)

    Miao, Quan; Travnikova, Oksana; Gel'mukhanov, Faris; Kimberg, Victor; Sun, Yu-Ping; Thomas, T Darrah; Nicolas, Christophe; Patanen, Minna; Miron, Catalin

    2015-05-01

    The vibrationally resolved X-ray photoelectron spectra of X2?g+(3?g?1) and B2?u+(2?u?1) states of N2+ were recorded for different photon energies and orientations of the polarization vector. Clear dependencies of the spectral line widths on the X-ray polarization as well as on the symmetry of the final electronic states are observed. Contrary to the translational Doppler, the rotational Doppler broadening is sensitive to the photoelectron emission anisotropy. On the basis of theoretical modeling, we suggest that the different rotational Doppler broadenings observed for gerade and ungerade final states result from a Young's double-slit interference phenomenon. PMID:26263315

  13. Laser Doppler anemometer signal processing for blood flow velocity measurements

    Science.gov (United States)

    Borozdova, M. A.; Fedosov, I. V.; Tuchin, V. V.

    2015-03-01

    A new method for analysing the signal in a laser Doppler anemometer based on the differential scheme is proposed, which provides the flow velocity measurement in strongly scattering liquids, particularly, blood. A laser Doppler anemometer intended for measuring the absolute blood flow velocity in animal and human near-surface arterioles and venules is developed. The laser Doppler anemometer signal structure is experimentally studied for measuring the flow velocity in optically inhomogeneous media, such as blood and suspensions of scattering particles. The results of measuring the whole and diluted blood flow velocity in channels with a rectangular cross section are presented.

  14. [Feasibility study of the Doppler exploration of the renal artery].

    Science.gov (United States)

    Milon, P; Clavier, E; Genevois, A; Benozio, M

    1990-03-01

    Using arteriography as a reference, the authors investigate the feasibility of pulsed doppler exploration of the normal or pathological renal arteries in 46 successive patients. The poor sensitivity of pulsed doppler, mainly due to the considerable anatomical variations of the renal pedicle, does not currently allow using this technique for the detection of renal arterial stenosis. When combined with angiography, pulsed doppler becomes a definite asset in therapeutic radiology to help in the choice of a treatment and in follow-up. PMID:2191123

  15. Processor operated correlator with applications to laser Doppler signals

    DEFF Research Database (Denmark)

    Bisgaard, C.; Johnsen, B.; Hassager, Ole

    1984-01-01

    A 64-channel correlator is designed with application to the processing of laser Doppler anemometry signals in the range 200 Hz to 250 kHz. The correlator is processor operated to enable the consecutive sampling of 448 correlation functions at a rate up to 500 Hz. Software is described to identify a...... Doppler frequency from each correlation and the system is especially designed for transient flow signals. Doppler frequencies are determined with an accuracy of about 0.1%. Review of Scientific Instruments is copyrighted by The American Institute of Physics....

  16. Diagnostic sensitivity and specificity of Doppler ultrasound in rheumatoid arthritis

    DEFF Research Database (Denmark)

    Terslev, L.; Recke, P. von der; Torp-Pedersen, S.; Koenig, M.J.; Bliddal, H.

    2008-01-01

    Objective. To evaluate the sensitivity and specificity of Doppler ultrasound (DUS) in diagnosing arthritis in the wrist and hands, and, if possible, to define a cutoff level for our ultrasound measures for inflammation, resistive index (RI), and color fraction. Methods. Using DUS, 88 patients with...... active RA were selected for study and 27 healthy controls. A total of 419 joints were examined. The synovial vascularization was determined by color Doppler and spectral Doppler estimating the color fraction (the percentage of color pixels inside the synovium was the region of interest) and RI in wrist...

  17. A Rayleigh Doppler frequency estimator derived from maximum likelihood theory

    DEFF Research Database (Denmark)

    Hansen, Henrik; Affes, Sofiéne; Mermelstein, Paul

    Reliable estimates of Rayleigh Doppler frequency are useful for the optimization of adaptive multiple access wireless receivers. The adaptation parameters of such receivers are sensitive to the amount of Doppler and automatic reconfiguration to the speed of terminal movement can optimize cell...... capacities in low and high speed situations. We derive a Doppler frequency estimator using the maximum likelihood method and Jakes model (1974) of a Rayleigh fading channel. This estimator requires an FFT and simple post-processing only. Its performance is verified through simulations and found to yield good...

  18. A Rayleigh Doppler Frequency Estimator Derived from Maximum Likelihood Theory

    DEFF Research Database (Denmark)

    Hansen, Henrik; Affes, Sofiene; Mermelstein, Paul

    1999-01-01

    Reliable estimates of Rayleigh Doppler frequency are useful for the optimization of adaptive multiple access wireless receivers.The adaptation parameters of such receivers are sensitive to the amount of Doppler and automatic reconfiguration to the speed of terminalmovement can optimize cell...... capacities in low and high speed situations.We derive a Doppler frequency estimatorusing the maximum likelihood method and Jakes model [\\ref{Jakes}] of a Rayleigh fading channel. This estimator requires an FFT and simple post-processing only. Its performance is verifiedthrough simulations and found to yield...

  19. A comparison of Doppler optical coherence tomography methods

    OpenAIRE

    Liu, Gangjun; Lin, Alexander J; TROMBERG, BRUCE J.; Chen, Zhongping

    2012-01-01

    Abstract: We compare, in detail, the phase-resolved color Doppler (PRCD), phase-resolved Doppler variance (PRDV) and intensity-based Doppler variance (IBDV) methods. All the methods are able to quantify flow speed when the flow rate is within a certain range, which is dependent on the adjacent A-line time interval. While PRCD is most sensitive when the flow direction is along the probing beam, PRDV and IBDV can be used to measure the flow when the flow direction is near perpendicular to the p...

  20. Sub-Doppler laser cooling of potassium atoms

    International Nuclear Information System (INIS)

    We investigate the sub-Doppler laser cooling of bosonic potassium isotopes, whose small hyperfine splitting has so far prevented cooling below the Doppler temperature. We find instead that the combination of a dark optical molasses scheme that naturally arises in this kind of system and an adiabatic ramping of the laser parameters allows us to reach sub-Doppler temperatures for small laser detunings. We demonstrate temperatures as low as 25±3 ?K and 47±5 ?K in high-density samples of the two isotopes 39K and 41K, respectively. Our findings should find application to other atomic systems.

  1. Laboratory evaluation of microwave Doppler velocimeter for solid flow measurements

    Science.gov (United States)

    Wu, Z.; Wang, H. G.; Isa, M.; Liu, C. G.

    2014-04-01

    Pneumatic-conveyed solid flows are common in many industrial processes. The flow speed may be high and varying. The density of solids may also change with time. The mass flow rate is usually difficult to quantify for such multphase flows. On the other hand, microwave Doppler radar has been used as a device for velocity measurement or motion detection. It would be feasible to use such a device for solid flow measurements. In this paper, the principle of using microwave Doppler radar for such an application is investigated. Experimental results obtained using a microwave Doppler velocimeter for different types of solid flows in a laboratory environment are presented.

  2. Interferometric millimeter wave and THz wave doppler radar

    Science.gov (United States)

    Liao, Shaolin; Gopalsami, Nachappa; Bakhtiari, Sasan; Raptis, Apostolos C.; Elmer, Thomas

    2015-08-11

    A mixerless high frequency interferometric Doppler radar system and methods has been invented, numerically validated and experimentally tested. A continuous wave source, phase modulator (e.g., a continuously oscillating reference mirror) and intensity detector are utilized. The intensity detector measures the intensity of the combined reflected Doppler signal and the modulated reference beam. Rigorous mathematics formulas have been developed to extract bot amplitude and phase from the measured intensity signal. Software in Matlab has been developed and used to extract such amplitude and phase information from the experimental data. Both amplitude and phase are calculated and the Doppler frequency signature of the object is determined.

  3. Advances in Direct Detection Doppler Lidar Technology and Techniques

    Science.gov (United States)

    Gentry, Bruce; Einaudi, Franco (Technical Monitor)

    2001-01-01

    In this paper we will describe the ground based Doppler lidar system which is mounted in a modified delivery van to allow field deployment and operations. The system includes an aerosol double edge receiver optimized for aerosol backscatter Doppler measurements at 1064 nm and a molecular double edge receiver which operates at 355 nm. The lidar system will be described including details of the injection seeded diode pumped laser transmitter and the piezoelectrically tunable high spectral resolution Fabry Perot etalon which is used to measure the Doppler shift. Examples of tropospheric wind profiles obtained with the system will also be presented to demonstrate its capabilities.

  4. The Next Generation Airborne Polarimetric Doppler Radar

    Science.gov (United States)

    Vivekanandan, J.; Lee, Wen-Chau; Loew, Eric; Salazar, Jorge; Chandrasekar, V.

    2013-04-01

    NCAR's Electra Doppler radar (ELDORA) with a dual-beam slotted waveguide array using dual-transmitter, dual-beam, rapid scan and step-chirped waveform significantly improved the spatial scale to 300m (Hildebrand et al. 1996). However, ELDORA X-band radar's penetration into precipitation is limited by attenuation and is not designed to collect polarimetric measurements to remotely estimate microphysics. ELDORA has been placed on dormancy because its airborne platform (P3 587) was retired in January 2013. The US research community has strongly voiced the need to continue measurement capability similar to the ELDORA. A critical weather research area is quantitative precipitation estimation/forecasting (QPE/QPF). In recent years, hurricane intensity change involving eye-eyewall interactions has drawn research attention (Montgomery et al., 2006; Bell and Montgomery, 2006). In the case of convective precipitation, two issues, namely, (1) when and where convection will be initiated, and (2) determining the organization and structure of ensuing convection, are key for QPF. Therefore collocated measurements of 3-D winds and precipitation microphysics are required for achieving significant skills in QPF and QPE. Multiple radars in dual-Doppler configuration with polarization capability estimate dynamical and microphysical characteristics of clouds and precipitation are mostly available over land. However, storms over complex terrain, the ocean and in forest regions are not observable by ground-based radars (Bluestein and Wakimoto, 2003). NCAR/EOL is investigating potential configurations for the next generation airborne radar that is capable of retrieving dynamic and microphysical characteristics of clouds and precipitation. ELDORA's slotted waveguide array radar is not compatible for dual-polarization measurements. Therefore, the new design has to address both dual-polarization capability and platform requirements to replace the ELDORA system. NCAR maintains a C-130 aircraft in its fleet for airborne atmospheric measurements, including dropsonde, and in situ sampling and remote sensing of clouds, chemistry and aerosols. Therefore, the addition of a precipitation radar to the NSF/NCAR C-130 platform will produce transformational change in its mission. This new design can be cloned for C-130s operated by a number of agencies, including NOAA and the Air Force hurricane reconnaissance fleet. This paper presents a possible configuration of a novel, airborne phased array radar (APAR) to be installed on the NSF/NCAR C-130 aircraft with improved spatial resolution and polarimetric capability to meet or exceed that of ELDORA. The preliminary design, an update of the APAR project, and a future plan will be presented. References: Bell, M. M. , M. T. Montgomery, 2008: Observed Structure, Evolution, and Potential Intensity of Category 5 Hurricane Isabel (2003) from 12 to 14 September. Monthly Weather Review, Vol. 136, Issue 6, pp. 2023-2046. Hildebrand, P. H., W.-C. Lee, C. A. Walther, C. Frush, M. Randall, E. Loew, R. Neitzel, R. Parsons, J. Testud, F. Baudin, and A. LeCornec, 1996: The ELDORA/ASTRAIA airborne Doppler weather radar: High resolution observations from TOGA COARE. Bull. Amer. Metoro. Soc., 77, 213-232 Howard B. Bluestein, Roger M. Wakimoto, 2003: Mobile Radar Observations of Severe Convective Storms re Convective Storms. Meteorological Monographs, Vol. 30, Issue 52, pp. 105-105. Montgomery, M. T., M. M. Bell, S. D. Aberson, M. L. Black, 2006: Hurricane Isabel (2003): New Insights into the Physics of Intense Storms. Part I: Mean Vortex Structure and Maximum Intensity Estimates. Bull. of the American Meteorl. Soc., Vol. 87, Issue 10, pp. 1335-1347.

  5. Evaluation of a meteorological airborne pulse Doppler radar

    Science.gov (United States)

    Trotter, B. L.; Strauch, R. G.; Frush, C. L.

    1980-07-01

    An X-band airborne radar has been modified to provide a Doppler radar capability. The Doppler radar has been tested to prove the system concept usable. Tests were conducted at Norman, Oklahoma, from May 30 to June 9 of 1978 and in Miami, Florida, on December 1 through December 5, 1979. Optimally the tests would have used meteorological targets for measurement of radial velocities, however, most tests had to be conducted with chaff and ground returns. The tests did show that the airborne Doppler radar will measure velocities that are comparable to those measured by a ground based Doppler radar and those that can be computed by a high accuracy inertial navigation system. The error in the measured radial velocities, when compared to other sensors, is much less than the estimated RMS error of 2 meters/second.

  6. Doppler-free spectroscopy in driven three-level systems

    CERN Document Server

    Rapol, U D; Rapol, Umakant D.; Natarajan, Vasant

    2004-01-01

    We demonstrate two techniques for studying the features of three-level systems driven by two lasers (called control and probe), when the transitions are Doppler broadened as in room-temperature vapor. For $\\Lambda$-type systems, the probe laser is split to produce a counter-propagating pump beam that saturates the transition for the zero-velocity atoms. Probe transmission then shows Doppler-free peaks, which can even have sub-natural linewidth. For V-type systems, the transmission of the control beam is detected as the probe laser is scanned. The signal shows Doppler-free peaks when the probe laser is resonant with transitions for the zero-velocity group. Both techniques greatly simplify the study of three-level systems since theoretical predictions can be directly compared without complications from Doppler broadening and the presence of multiple hyperfine levels in the spectrum.

  7. Ultrasonic Doppler methods to extract signatures of a walking human.

    Science.gov (United States)

    Mehmood, Asif; Sabatier, James M; Damarla, Thyagaraju

    2012-09-01

    Extraction of Doppler signatures that characterize human motion has attracted a growing interest in recent years. These Doppler signatures are generated by various components of the human body while walking, and contain unique features that can be used for human detection and recognition. Although, a significant amount of research has been done in radio frequency regime for human Doppler signature extraction, considerably less has been done in acoustics. In this work, 40 kHz ultrasonic sonar is employed to measure the Doppler signature generated by the motion of body segments using different electronic and signal processing schemes. These schemes are based on both analog and digital demodulation with homodyne and heterodyne receiver circuitry. The results and analyses from these different schemes are presented. PMID:22979839

  8. WIMS-AECL calculations for the Doppler coefficient of reactivity

    International Nuclear Information System (INIS)

    The Doppler coefficient of reactivity is an important parameter in the evaluation of reactor transients. The Doppler feedback, associated with changes in fuel temperature when a reactor goes from hot zero power to hot full power, is a relatively small effect which is difficult to measure directly. WIMS-AECL calculations of the Doppler coefficient of reactivity are in excellent agreement with those predicted by MCNP-3A. It is shown that the WIMS-AECL lattice code, together with the WIMS ENDF/B-V data library, can predict the Doppler coefficient of light-water reactor fuel with good accuracy. The results can be used in SLOWPOKE, MAPLE, or other reactor calculations. 7 refs., 8 tabs

  9. CAMEX-4 MIPS 915 MHZ DOPPLER WIND PROFILER V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The University of Alabama in Huntsville (UAH) Mobile Integrated Profiling System (MIPS) is a mobile atmospheric profiling system. It includes a 915 MHz Doppler...

  10. Doppler Signatures of the Atmospheric Circulation on Hot Jupiters

    CERN Document Server

    Showman, Adam P; Lewis, Nikole K; Shabram, Megan

    2013-01-01

    The meteorology of hot Jupiters has been characterized primarily with thermal measurements, but recent observations suggest the possibility of directly detecting the winds by observing the Doppler shift of spectral lines seen during transit. Motivated by these observations, we show how Doppler measurements can place powerful constraints on the meteorology. We show that the atmospheric circulation--and Doppler signature--of hot Jupiters splits into two regimes. Under weak stellar insolation, the day-night thermal forcing generates fast zonal jet streams from the interaction of atmospheric waves with the mean flow. In this regime, air along the terminator (as seen during transit) flows toward Earth in some regions and away from Earth in others, leading to a Doppler signature exhibiting superposed blue- and redshifted components. Under intense stellar insolation, however, the strong thermal forcing damps these planetary-scale waves, inhibiting their ability to generate jets. Strong frictional drag likewise damps...

  11. Extracting and analyzing micro-Doppler from ladar signatures

    Science.gov (United States)

    Tahmoush, Dave

    2015-05-01

    Ladar and other 3D imaging modalities have the capability of creating 3D micro-Doppler to analyze the micro-motions of human subjects. An additional capability to the recognition of micro-motion is the recognition of the moving part, such as the hand or arm. Combined with measured RCS values of the body, ladar imaging can be used to ground-truth the more sensitive radar micro-Doppler measurements and associate the moving part of the subject with the measured Doppler and RCS from the radar system. The 3D ladar signatures can also be used to classify activities and actions on their own, achieving an 86% accuracy using a micro-Doppler based classification strategy.

  12. The Doppler Effect: A Consideration of Quasar Redshifts.

    Science.gov (United States)

    Gordon, Kurtiss J.

    1980-01-01

    Provides information on the calculation of the redshift to blueshift ratio introduced by the transverse Doppler effect at relativistic speeds. Indicates that this shift should be mentioned in discussions of whether quasars are "local" rather than "cosmological" objects. (GS)

  13. Laser Doppler technology applied to atmospheric environmental operating problems

    Science.gov (United States)

    Weaver, E. A.; Bilbro, J. W.; Dunkin, J. A.; Jeffreys, H. B.

    1976-01-01

    Carbon dioxide laser Doppler ground wind data were very favorably compared with data from standard anemometers. As a result of these measurements, two breadboard systems were developed for taking research data: a continuous wave velocimeter and a pulsed Doppler system. The scanning continuous wave laser Doppler velocimeter developed for detecting, tracking and measuring aircraft wake vortices was successfully tested at an airport where it located vortices to an accuracy of 3 meters at a range of 150 meters. The airborne pulsed laser Doppler system was developed to detect and measure clear air turbulence (CAT). This system was tested aboard an aircraft, but jet stream CAT was not encountered. However, low altitude turbulence in cumulus clouds near a mountain range was detected by the system and encountered by the aircraft at the predicted time.

  14. A Digital Multigate Doppler Method for High Frequency Ultrasound

    Directory of Open Access Journals (Sweden)

    Weibao Qiu

    2014-07-01

    Full Text Available Noninvasive visualization of blood flow with high frequency Doppler ultrasound has been extensively used to assess the morphology and hemodynamics of the microcirculation. A completely digital implementation of multigate pulsed-wave (PW Doppler method was proposed in this paper for high frequency ultrasound applications. Analog mixer was eliminated by a digital demodulator and the same data acquisition path was shared with traditional B-mode imaging which made the design compact and flexible. Hilbert transform based quadrature demodulation scheme was employed to achieve the multigate Doppler acquisition. A programmable high frequency ultrasound platform was also proposed to facilitate the multigate flow visualization. Experimental results showed good performance of the proposed method. Parabolic velocity gradient inside the vessel and velocity profile with different time slots were acquired to demonstrate the functionality of the multigate Doppler. Slow wall motion was also recorded by the proposed method.

  15. Value of intraplacental villous artery Doppler measurements in severe preeclampsia.

    Directory of Open Access Journals (Sweden)

    Lacin S

    1996-10-01

    Full Text Available Blood flow velocity waveforms were recorded by color Doppler ultrasound from intraplacental villous and umbilical arteries in 20 normal and 23 severe preeclamptic pregnancies. The results of the resistance index measurements in intraplacental villous arteries were 0.51 +/- 0.037 and 0.55 +/- 0.052 in healthy controls and preeclamptics respectively, which was not significantly different. Resistance indices showed a decrease through the umbilical cord from fetus to placenta in both groups. We also noted that Doppler examination of the umbilical cord might be an early indicator of fetal compromise. Detectable intraplacental villous flows were in normal limits even in patients with abnormally high umbilical resistance indices and failure to detect villous artery color Doppler flow signals is probably associated with fetal compromise. We conclude that Doppler measurements from the intraplacental arteries cannot be used in clinical management of patients with severe preeclampsia.

  16. GRIP DOPPLER AEROSOL WIND LIDAR (DAWN) V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The Doppler Aerosol WiNd (DAWN), a pulsed lidar, operated aboard a NASA DC-8 aircraft during the Genesis and Rapid Intensification Processes (GRIP) field campaign....

  17. Estimation of amputation level with a laser Doppler flowmeter

    DEFF Research Database (Denmark)

    Gebuhr, Peter Henrik; Jørgensen, J P; Vollmer-Larsen, B; Nielsen, S L; Alsbjørn, B

    1989-01-01

    Leg amputation levels were decided in 24 patients suffering from atherosclerosis, using the conventional techniques of segmental blood pressure and radioisotope skin clearance. The skin microcirculation was measured and recorded before operation with a laser doppler flowmeter. A high correlation...

  18. Doppler electron velocimetry : notes on creating a practical tool.

    Energy Technology Data Exchange (ETDEWEB)

    Reu, Phillip L.; Milster, Tom (University of Arizona)

    2008-11-01

    The Doppler electron velocimeter (DEV) has been shown to be theoretically possible. This report attempts to answer the next logical question: Is it a practical instrument? The answer hinges upon whether enough electrons are available to create a time-varying Doppler current to be measured by a detector with enough sensitivity and bandwidth. The answer to both of these questions is a qualified yes. A target Doppler frequency of 1 MHz was set as a minimum rate of interest. At this target a theoretical beam current signal-to-noise ratio of 25-to-1 is shown for existing electron holography equipment. A detector is also demonstrated with a bandwidth of 1-MHz at a current of 10 pA. Additionally, a Linnik-type interferometer that would increase the available beam current is shown that would offer a more flexible arrangement for Doppler electron measurements over the traditional biprism.

  19. CAMEX-4 MIPS 915 MHZ DOPPLER WIND PROFILER V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The University of Alabama in Huntsville (UAH) Mobile Integrated Profiling System (MIPS) is a mobile atmospheric profiling system. It includes a 915 MHz Doppler...

  20. Coherent Doppler Lidar for Precision Navigation of Spacecrafts

    Science.gov (United States)

    Amzajerdian, Farzin; Pierrottet, Diego; Petway, Larry; Hines, Glenn; Lockhard, George; Barnes, Bruce

    2011-01-01

    A fiber-based coherent Doppler lidar, utilizing an FMCW technique, has been developed and its capabilities demonstrated through two successful helicopter flight test campaigns. This Doppler lidar is expected to play a critical role in future planetary exploration missions because of its ability in providing the necessary data for soft landing on the planetary bodies and for landing missions requiring precision navigation to the designated location on the ground. Compared with radars, the Doppler lidar can provide significantly higher precision velocity and altitude data at a much higher rate without concerns for measurement ambiguity or target clutter. Future work calls for testing the Doppler lidar onboard a rocket-powered free-flyer platform operating in a closed-loop with the vehicle s guidance, navigation, and control (GN&C) unit.

  1. Doppler ultrasound in obstetrics and gynecology. 2. rev. and enl. ed.

    International Nuclear Information System (INIS)

    The second edition of Doppler Ultrasound in Obstetrics and Gynecology has been expanded and comprehensively updated to present the current standards of practice in Doppler ultrasound and the most recent developments in the technology. Doppler Ultrasound in Obstetrics and Gynecology encompasses the full spectrum of clinical applications of Doppler ultrasound for the practicing obstetrician-gynecologist, including the latest advances in 3D and color Doppler and the newest techniques in 4D fetal echocardiography. Written by preeminent experts in the field, the book covers the basic and physical principles of Doppler ultrasound; the use of Doppler for fetal examination, including fetal cerebral circulation; Doppler echocardiography of the fetal heart; and the use of Doppler for postdated pregnancy and in cases of multiple gestation. Chapters on the use of Doppler for gynecologic investigation include ultrasound in ectopic pregnancy, for infertility, for benign disorders and for gynecologic malignancies. (orig.)

  2. Doppler ultrasound in obstetrics and gynecology. 2. rev. and enl. ed.

    Energy Technology Data Exchange (ETDEWEB)

    Maulik, D. [Winthrop Univ. Hospital, Mineola, NY (United States). Dept. of Obstetrics and Gynecology; Zalud, I. (eds.) [Kapiolani Medical Center for Women and Children, Honolulu, HI (United States)

    2005-07-01

    The second edition of Doppler Ultrasound in Obstetrics and Gynecology has been expanded and comprehensively updated to present the current standards of practice in Doppler ultrasound and the most recent developments in the technology. Doppler Ultrasound in Obstetrics and Gynecology encompasses the full spectrum of clinical applications of Doppler ultrasound for the practicing obstetrician-gynecologist, including the latest advances in 3D and color Doppler and the newest techniques in 4D fetal echocardiography. Written by preeminent experts in the field, the book covers the basic and physical principles of Doppler ultrasound; the use of Doppler for fetal examination, including fetal cerebral circulation; Doppler echocardiography of the fetal heart; and the use of Doppler for postdated pregnancy and in cases of multiple gestation. Chapters on the use of Doppler for gynecologic investigation include ultrasound in ectopic pregnancy, for infertility, for benign disorders and for gynecologic malignancies. (orig.)

  3. Using doppler radar images to estimate aircraft navigational heading error

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin W. (Albuquerque, NM); Jordan, Jay D. (Albuquerque, NM); Kim, Theodore J. (Albuquerque, NM)

    2012-07-03

    A yaw angle error of a motion measurement system carried on an aircraft for navigation is estimated from Doppler radar images captured using the aircraft. At least two radar pulses aimed at respectively different physical locations in a targeted area are transmitted from a radar antenna carried on the aircraft. At least two Doppler radar images that respectively correspond to the at least two transmitted radar pulses are produced. These images are used to produce an estimate of the yaw angle error.

  4. Analysis of Radar Doppler Signature from Human Data

    OpenAIRE

    M. Andrić; Bujaković, D.; B. BONDZULIĆ; Simić, S.; Zrnić, B.

    2014-01-01

    This paper presents the results of time (autocorrelation) and time-frequency (spectrogram) analyses of radar signals returned from the moving human targets. When a radar signal falls on the human target which is moving toward or away from the radar, the signals reflected from different parts of his body produce a Doppler shift that is proportional to the velocity of those parts. Moving parts of the body causes the characteristic Doppler signature. The main contribution comes from the torso wh...

  5. A Human Gait Classification Method Based on Radar Doppler Spectrograms

    OpenAIRE

    Fok Hing Chi Tivive; Abdesselam Bouzerdoum; Amin, Moeness G.

    2010-01-01

    An image classification technique, which has recently been introduced for visual pattern recognition, is successfully applied for human gait classification based on radar Doppler signatures depicted in the time-frequency domain. The proposed method has three processing stages. The first two stages are designed to extract Doppler features that can effectively characterize human motion based on the nature of arm swings, and the third stage performs classification. Three types of arm motion are...

  6. Holographic laser Doppler imaging of microvascular blood flow

    OpenAIRE

    Magnain, C.; Castel, A.; Boucneau, T.; Simonutti, M.; Ferezou, I.; Rancillac, A.; Vitalis, T; Sahel, J. A.; Paques, M; Atlan, M.

    2014-01-01

    We report on local superficial blood flow monitoring in biological tissue from laser Doppler holographic imaging. In time averaging recording conditions, holography acts as a narrowband bandpass filter, which, combined with a frequency shifted reference beam, permits frequency selective imaging in the radiofrequency range. These Doppler images are acquired with an off axis Mach Zehnder interferometer. Microvascular hemodynamic components mapping is performed in the cerebral ...

  7. DELAY-DOPPLER PERFORMANCE OF HYPERBOLIC FREQUENCY MODULATION WAVEFORMS

    OpenAIRE

    A.NAGAJYOTHI; Raja Rajeswari, K.

    2013-01-01

    Doppler effect plays a vital role and cannot be neglected for high velocity radars. When the velocity between the target and radar is very high compared to the velocity of transmitted waveform, then the received signal suffers Doppler distortion and will not match with the matched filter. Due to this, linear frequency modulation waveform suffers from a considerable signal loss. Use of hyperbolic frequency modulation eliminates this adverse effect. In this paper hyperbolic frequenc...

  8. Doppler Tomography in Cataclysmic Variables: an historical perspective

    OpenAIRE

    Echevarria, J.

    2012-01-01

    To mark the half-century anniversary of this newly-born field of Cataclysmic Variables, a special emphasis is made in this review, on the Doppler Effect as a tool in astrophysics. The Doppler Effect was in fact, discovered almost 170 years ago, and has been since, one of the most important tools which helped to develop modern astrophysics. We describe and discuss here, its use in Cataclysmic Variables which, combined with another important tool, the tomography, first devised...

  9. Precision Measuring of Velocities via the Relativistic Doppler Effect

    OpenAIRE

    Ozernoy, Leonid M.

    1997-01-01

    Just as the ordinary Doppler effect serves as a tool to measure radial velocities of celestial objects, so can the relativistic Doppler effect be implemented to measure a combination of radial and transverse velocities by using recent improvements in observing techniques. A key element that makes a further use of this combination feasible is the periodicity in changes of the orbital velocity direction for the source. Two cases are considered: (i) a binary star; and (ii) a so...

  10. A Modified Modulation Recognition Method against Doppler Effects

    OpenAIRE

    Yaqin Zhao; Song Chen; Hang Yu; Zhenguo Shi

    2011-01-01

    In this study, we present a modified modulation recognition method- the way to seek the slope (TW-STS), based on decision theory, which can classify 7 kinds of basic digital modulation signals well under the influence of Doppler Effect. The proposed scheme is obtained by analyzing the influence to instantaneous amplitude, instantaneous phase and instantaneous frequency caused by Doppler Effect and modifying the original modulation recognition model. It can retrain the influence well and then ...

  11. Special Theory of Relativity through the Doppler Effect

    OpenAIRE

    Moriconi, M

    2006-01-01

    We present the special theory of relativity taking the Doppler effect as the starting point, and derive several of its main effects, such as time dilation, length contraction, addition of velocities, and the mass-energy relation, and assuming energy and momentum conservation, we discuss how to introduce the 4-momentum in a natural way. We also use the Doppler effect to explain the "twin paradox", and its version on a cylinder. As a by-product we discuss Bell's spaceship para...

  12. Narrowing of EIT resonance in a Doppler Broadened Medium

    OpenAIRE

    Javan, Ali; Kocharovskaya, Olga; Lee, Hwang; Scully, Marlan O.

    2001-01-01

    We derive an analytic expression for the linewidth of EIT resonance in a Doppler broadened system. It is shown here that for relatively low intensity of the driving field the EIT linewidth is proportional to the square root of intensity and is independent of the Doppler width, similar to the laser induced line narrowing effect by Feld and Javan. In the limit of high intensity we recover the usual power broadening case where EIT linewidth is proportional to the intensity and ...

  13. Blood flow measurement by laser Doppler method in orofacial region

    OpenAIRE

    Grga ?urica; Dželetovi? Bojan; Živkovi? Slavoljub; Kršljak Elena

    2010-01-01

    Laser Doppler is a noninvasive, objective, reproducible and painless method for measuring blood flow in tissue microcirculation. This method is based on the Doppler effect, the change in frequency of light reflecting from blood cells in motion. Light from helium-neon laser through optical fibers and probes is directed to the surface of the tissue in which the flow is measured. Light portion is reflected from the cells in motion and changes the frequency while another portion is reflecte...

  14. Observations of 2D Doppler backscattering on MAST

    OpenAIRE

    Thomas, D A; Brunner, K. J.; Freethy, S J; Huang, B. K.; Shevchenko, V. F.; Vann, R. G. L.

    2015-01-01

    The Synthetic Aperture Microwave Imaging (SAMI) diagnostic has conducted proof-of-principle 2D Doppler backscattering (DBS) experiments on MAST. SAMI actively probes the plasma edge using a wide (+-40 degrees vertical and horizontal) and tuneable (10-35.5 GHz) beam. The Doppler backscattered signal is digitised in vector form using an array of eight Vivaldi PCB antennas. This allows the receiving array to be focused in any direction within the field of view simultaneously to...

  15. Influence of Doppler Bin Width on GPS Acquisition Probabilities

    OpenAIRE

    Geiger, Bernhard C.; Vogel, Christian

    2011-01-01

    Acquisition is a search in two continuous dimensions, where the digital algorithms require a partitioning of the search space into cells. Depending on the partitioning of the Doppler frequency domain, more than one cell might contain significant signal energy. We present an expression for the expected values of the cells' energies to analyze the impact of the Doppler bin width on detection and false alarm probabilities.

  16. Considerations for Designing a Space Based Coherent Doppler Lidar

    Science.gov (United States)

    Spiers, Gary D.; Kavaya, Michael J.

    1999-01-01

    An orbiting coherent Doppler lidar for measuring winds is required to provide two basic pieces of data to the user community. The first is the line of sight wind velocity and the second is knowledge of the position at which the measurement was made. In order to provide this information in regions of interest the instrument is also required to have a certain backscatter sensitivity level. This paper outlines some of the considerations necessary in designing a coherent Doppler lidar for this purpose.

  17. Observing crosswind over urban terrain using scintillometer and Doppler lidar

    OpenAIRE

    D. van Dinther; Wood, C.R.; Hartogensis, O. K.; A. Nordbo; E. J. O'Connor

    2015-01-01

    In this study, the crosswind (wind component perpendicular to a path, U⊥) is measured by a scintillometer and Doppler lidar above the urban environment of Helsinki, Finland, for 3 weeks. The scintillometer allows acquisition of a path-averaged value of U⊥ (U⊥), while the Doppler lidar allows acquisition of path-resolved U⊥ (U⊥ (x), where x is the position along the path). The goal of this study is to evaluate t...

  18. The impact of airborne Doppler lidar observations on ECMWF forecasts

    OpenAIRE

    Weissmann, Martin; Cardinali, Carla

    2006-01-01

    During the Atlantic THORPEX Regional Campaign (A-TReC) in autumn 2003, the airborne Doppler lidar of the Deutsches Zentrum für Luft- und Raumfahrt (DLR) was used to observe wind in predicted sensitive regions. In eight flights, the system measured a total of 1600 wind profiles that were experimentally assimilated in the global assimilation system at ECMWF. The present study assesses the impact of these Doppler lidar measurements in Numerical Weather Prediction (NWP). It is shown that lidar ob...

  19. Aircraft wake vortex measurement with airborne coherent Doppler lidar

    OpenAIRE

    Rahm, S; Smalikho, I.

    2008-01-01

    An experiment for airborne Doppler lidar measurement of wake vortices generated by a large transport aircraft in the free atmosphere has been successfully carried out. In this paper, the description of the experiment, data processing procedure, and measurement results are given. It was shown that the use of smoke generators placed on large transport aircraft wings allows some high-quality wake vortex measurements with 2 ?m coherent Doppler lidar installed in a second aircraft.

  20. Color doppler ultrasound diagonosis in cesarean scar pregnancy

    International Nuclear Information System (INIS)

    Objective: To study the sonographic characteristics of cesarean scar pregnancy(CSP), and the value of color Doppler in the diagnosis of CSP. Methods: Twelve cases of CSP were all confirmed by transabdominal and transvaginal ultrasound. Results: The ultrasonogram of CSP could be divided into gestational sac type and mixed mass type. Conclusion: Color Doppler can give guidance to the early diagnosis, treatment and following-up of CSP because of the sonographic specifity of CSP. (authors)

  1. Doppler velocimetry for predicting fetal death in a twin pregnancy.

    OpenAIRE

    Soikkeli, Pia; Dubiel, Mariusz; Gudmundsson, Saemundur

    2002-01-01

    Diagnosis of discordant twins is easily accomplished with modern ultrasound equipment, though diagnosing twin-to-twin transfusion syndrome (TTS) at an early stage might be a problem. The possibility of excluding TTS by Doppler ultrasound is demonstrated in a case with early severe growth restriction of one fetus. Characteristic blood velocity changes in a dying fetus are also illustrated. The Doppler technique has become an accepted method in obstetrics for antenatal surveillance, perm...

  2. Experimental Observation of Reversed Doppler Effects in Acoustic Metamaterials

    OpenAIRE

    Zhai, Shilong; Zhao, Xiaopeng; Liu, Song; Luo, Chunrong

    2015-01-01

    This paper reports an experimental observation of broadband reversed Doppler effects using an acoustic metamaterial with seven flute-like double-meta-molecule clusters. Simulations and experiments verify that this locally resonant acoustic metamaterial with simultaneous negative elastic modulus and mass density can realize negative refraction in a broad frequency range. The constructed metamaterial exhibits broadband reversed Doppler effects. The frequency shift increases co...

  3. Gravitational waves from coalescing binaries and Doppler experiments

    OpenAIRE

    Bertotti, Bruno; Vecchio, Alberto; Iess, Luciano

    1998-01-01

    Doppler tracking of interplanetary spacecraft provides the only method presently available for broad-band searches of low frequency gravitational waves. The instruments have a peak sensitivity around the reciprocal of the round-trip light-time T of the radio link connecting the Earth to the space-probe and therefore are particularly suitable to search for coalescing binaries containing massive black holes in galactic nuclei. A number of Doppler experiments -- the most recent involving the pro...

  4. Doppler techniques for blood microcirculation monitoring in dentistry

    Science.gov (United States)

    Starukhin, Pavel Y.; Kharish, Natalia A.; Ulyanov, Sergey S.; Lepilin, Alexander V.; Tuchin, Valery V.

    1997-12-01

    Some physiological aspects of paradont structure and blood microcirculation are described. Results of Monte-Carlo simulations of Doppler shift are presented for model of random medium that containing moving particles. The single- layered and two-layered configurations of the medium are considered. Doppler shift of the frequency of incident laser light is investigated as a function of such parameters as absorption coefficient, scattering coefficient, and thickness of the medium.

  5. New developments in photon Doppler velocimetry

    International Nuclear Information System (INIS)

    Photon Doppler velocimetry (PDV) has made the transition among many experimental groups from being a new diagnostic to being routinely fielded as a means of obtaining velocity data in high-speed test applications. Indeed, research groups both within and outside of the shock physics community have taken note of PDV's robust, high-performance measurement capabilities. As PDV serves as the primary diagnostic in an increasing number of experiments, it will continue to find new applications and enable the measurement of previously un-measurable phenomena. This paper provides a survey of recent developments in PDV system design and feature extraction as well as a discussion of new applications for PDV. More specifically, changes at the system level have enabled the collection of data sets that are far richer than those previously attainable in terms of spatial and temporal coverage as well as improvements over PDV's previously measurable velocity ranges. And until recently, PDV data have been analyzed almost exclusively in the frequency-domain; although the use of additional data analysis techniques is beginning to show promise, particularly as it pertains to extracting information from a PDV signal about surface motion that is not along the beam's axis.

  6. Doppler radar detection of vortex hazard indicators

    Science.gov (United States)

    Nespor, Jerald D.; Hudson, B.; Stegall, R. L.; Freedman, Jerome E.

    1994-01-01

    Wake vortex experiments were conducted at White Sands Missile Range, NM using the AN/MPS-39 Multiple Object Tracking Radar (MOTR). The purpose of these experiments was twofold. The first objective was to verify that radar returns from wake vortex are observed for some time after the passage of an aircraft. The second objective was to verify that other vortex hazard indicators such as ambient wind speed and direction could also be detected. The present study addresses the Doppler characteristics of wake vortex and clear air returns based upon measurements employing MOTR, a very sensitive C-Band phased array radar. In this regard, the experiment was conducted so that the spectral characteristics could be determined on a dwell to-dwell basis. Results are presented from measurements of the backscattered power (equivalent structure constant), radial velocity and spectral width when the aircraft flies transverse and axial to the radar beam. The statistics of the backscattered power and spectral width for each case are given. In addition, the scan strategy, experimental test procedure and radar parameters are presented.

  7. Selection Functions in Doppler Planet Searches

    CERN Document Server

    O'Toole, S J; Jones, H R A; Butler, R P; Marcy, G W; Carter, B; Bailey, J

    2008-01-01

    We present a preliminary analysis of the sensitivity of Anglo-Australian Planet Search data to the orbital parameters of extrasolar planets. To do so, we have developed new tools for the automatic analysis of large-scale simulations of Doppler velocity planet search data. One of these tools is the 2-Dimensional Keplerian Lomb-Scargle periodogram, that enables the straightforward detection of exoplanets with high eccentricities (something the standard Lomb-Scargle periodogram routinely fails to do). We used this technique to re-determine the orbital parameters of HD20782b, with one of the highest known exoplanet eccentricities (e=0.97+/-0.01). We also derive a set of detection criteria that do not depend on the distribution functions of fitted Keplerian orbital parameters (which we show are non-Gaussian with pronounced, extended wings). Using these tools, we examine the selection functions in orbital period, eccentricity and planet mass of Anglo-Australian Planet Search data for three planets with large-scale ...

  8. Hydronephrosis and pregnancy: study with Doppler echography

    International Nuclear Information System (INIS)

    An 18-month study was performed to establish the normal intrarenal resistance index during pregnancy, in order to determine whether it differed significantly depending on the week of gestation or the degree of hydronephrosis. For this purpose , the flow velocity waves obtained in right kidney were analyzed in a group of 112 patients on the basis of 209 explorations. The kidneys were classified as grade 0,I,II, or III according to the degree of hydronephrosis. Doppler signal sampling was carried out at the level of the corticomedullary junction. From the results of the study it can be deduced that the index of intrarenal resistance during pregnancy is similar to that of the general population, that there are no significant differences among the groups with different degree of hydronephrosis and that the index does not vary according to the different weeks of gestation. These findings suggest that, during pregnancy, a pathological resistance index in a kidney should not be attributed to the physiological changes associated with normal gestation. (Author) 21 refs

  9. Single mode, extreme precision Doppler spectrographs

    CERN Document Server

    Schwab, Christian; Betters, Christopher H; Bland-Hawthorn, Joss; Mahadevan, Suvrath

    2012-01-01

    The 'holy grail' of exoplanet research today is the detection of an earth-like planet: a rocky planet in the habitable zone around a main-sequence star. Extremely precise Doppler spectroscopy is an indispensable tool to find and characterize earth-like planets; however, to find these planets around solar-type stars, we need nearly one order of magnitude better radial velocity (RV) precision than the best current spectrographs provide. Recent developments in astrophotonics (Bland-Hawthorn & Horton 2006, Bland-Hawthorn et al. 2010) and adaptive optics (AO) enable single mode fiber (SMF) fed, high resolution spectrographs, which can realize the next step in precision. SMF feeds have intrinsic advantages over multimode fiber or slit coupled spectrographs: The intensity distribution at the fiber exit is extremely stable, and as a result the line spread function of a well-designed spectrograph is fully decoupled from input coupling conditions, like guiding or seeing variations (Ihle et al. 2010). Modal noise, a...

  10. Muscle activity characterization by laser Doppler Myography

    Science.gov (United States)

    Scalise, Lorenzo; Casaccia, Sara; Marchionni, Paolo; Ercoli, Ilaria; Primo Tomasini, Enrico

    2013-09-01

    Electromiography (EMG) is the gold-standard technique used for the evaluation of muscle activity. This technique is used in biomechanics, sport medicine, neurology and rehabilitation therapy and it provides the electrical activity produced by skeletal muscles. Among the parameters measured with EMG, two very important quantities are: signal amplitude and duration of muscle contraction, muscle fatigue and maximum muscle power. Recently, a new measurement procedure, named Laser Doppler Myography (LDMi), for the non contact assessment of muscle activity has been proposed to measure the vibro-mechanical behaviour of the muscle. The aim of this study is to present the LDMi technique and to evaluate its capacity to measure some characteristic features proper of the muscle. In this paper LDMi is compared with standard superficial EMG (sEMG) requiring the application of sensors on the skin of each patient. sEMG and LDMi signals have been simultaneously acquired and processed to test correlations. Three parameters has been analyzed to compare these techniques: Muscle activation timing, signal amplitude and muscle fatigue. LDMi appears to be a reliable and promising measurement technique allowing the measurements without contact with the patient skin.

  11. Transcranial Doppler sonography in adult hydrocephalic patients.

    Science.gov (United States)

    Rainov, N G; Weise, J B; Burkert, W

    2000-03-01

    Transcranial Doppler sonography (TCD) is a noninvasive technique for measurement of cerebral blood flow velocity (CBFV) in the major arteries of the circle of Willis. Dynamic changes in the pulsatility index (PI) and the resistance index (RI), as calculated from TCD data, allow for an assessment of the forces acting on the terminal vasculature of the brain. The present study was designed to investigate a possible relationship between TCD parameters and intracranial pressure (ICP) changes in adult patients with hypertensive hydrocephalus. Blood flow velocity in the middle cerebral artery (MCA) was studied by TCD in 29 hydrocephalus patients and in 20 healthy controls. ICP was measured in the patient group before ventricular shunting and was correlated with TCD data. The mean CBFV in hydrocephalic patients prior to ventriculoperitoneal shunting was significantly lower than in the control group. Compared to normal persons, systolic and end-diastolic CBFV values in patients were significantly decreased, suggesting an increased distal cerebrovascular resistance. PI and RI values in patients with elevated ICP prior to shunting were significantly increased in comparison to those of normal persons. There was a statistically significant positive correlation of preshunting ICP and mean preshunting values of RI (r=0.50, P35 mm Hg (n=6), the changes described above were more pronounced than in the subgroup with preshunting ICP values hydrocephalus, although an exact noninvasive measurement of ICP by TCD seems impossible. Changes in the RI and PI indices appear to be useful indicators of elevated ICP. PMID:10809485

  12. Image-based tracking laser Doppler vibrometer

    International Nuclear Information System (INIS)

    An innovative version of the tracking laser Doppler vibrometer based on image acquisition and processing (iTLDV) is proposed. The iTLDV is developed for tracking of arbitrary motions; the system is feedback controlled and allows measuring the vibrations of a moving target by driving moving mirrors via position signals of the target obtained from a charge-coupled-device camera and an image processing algorithm. The tracking system developed has been applied to an industrial test case subject to self-excited vibrations, in order to verify the performances and limits in the operating conditions. The system demonstrates its ability to measure vibration time histories on a windscreen wiper in operative conditions. This test case represents a challenging measurement problem, since no other measurement techniques are available that are able to extract such data. Some examples of obtained data are shown, which highlight the potential of iTLDV. In addition, position accuracy and measurement uncertainty are discussed. For the windscreen wiper, the worst position accuracy is estimate as ±1.2 mm along the wiper axis, while the measurement uncertainty mainly depends on the commercial vibrometer applied in the setup (about ±2% depending on operative conditions)

  13. Satellite Doppler Fixation and International Boundaries

    Science.gov (United States)

    Leppard, N. A. G.

    1980-01-01

    International boundaries have seldom been completely defined in geodetic terms. The existence of natural resources, which ignore the arbitrary boundaries of man, assume considerable importance when division of those resources becomes a point of issue between potential owners. This is particularly so when the boundary is illdefined in a geodetic sense. World-wide satellite reference systems, like natural resources, also have little regard for the internally less precise national or international systems. When the one is used to define the location of the other, great care must be taken to ensure equitable division, for financial gain and loss can be considerable. The definition of position is complicated by the existence of the two ephemerides for the N.N.S.S. satellites and the number of alternative reduction procedures available. The definition of the position of the Frigg Gas Field in the North Sea is an example of how the United Kingdom and Norway resolved the geodetic problem of reconciling geodetic and Doppler data.

  14. Doppler cooling of a Coulomb crystal

    CERN Document Server

    Morigi, G; Morigi, Giovanna; Eschner, Juergen

    2001-01-01

    We study theoretically Doppler laser-cooling of a cluster of 2-level atoms confined in a linear ion trap. Using several consecutive steps of averaging we derive, from the full quantum mechanical master equation, an equation for the total mechanical energy of the one dimensional crystal, defined on a coarse-grained energy scale whose grid size is smaller than the linewidth of the electronic transition. This equation describes the cooling dynamics for an arbitrary number of ions and in the quantum regime. We discuss the validity of the ergodic assumption (i.e. that the phase space distribution is only a function of energy). From our equation we derive the semiclassical limit (i.e. when the mechanical motion can be treated classically) and the Lamb-Dicke limit (i.e. when the size of the mechanical wave function is much smaller than the laser wavelength). We find a Fokker-Planck equation for the total mechanical energy of the system, whose solution is in agreement with previous analytical calculations which were ...

  15. Miniature laser Doppler anemometer for sensor concepts

    Science.gov (United States)

    Damp, Stephan

    1991-07-01

    Laser Doppler Anemometry (LDA) is well established in fluid dynamic research. Most wind tunnel and water tunnel experiments are supported by LDA measurements due to their ability to measure instantaneous velocities with high precision. However, the classical LDA equipment is very voluminous, has large power consumption and needs skilled staff for operation. Because LDA is a nonintrusive measuring procedure with no calibration needs, its use outside the laboratory would be very interesting. Process control and calibration of classical fluid sensors can be considered to be the main applications. Along with semiconductor lasers and detectors instead of gas lasers and photomultipliers, a dramatic reduction in spatial volume and power consumption results. Therefore, essential requirements for a sensor concept are fulfilled. The paper presents a miniaturized LDA as a sensor head. It has the dimensions of 4.7 cm by 4.5 cm by 5.7 cm. It consumes less than 3 W electrical power on a 12 V power supply. The measuring distance is 9.5 cm. The velocity range which can be covered reaches from 5 m/s up to 500 m/s.

  16. Muscle activity characterization by laser Doppler Myography

    International Nuclear Information System (INIS)

    Electromiography (EMG) is the gold-standard technique used for the evaluation of muscle activity. This technique is used in biomechanics, sport medicine, neurology and rehabilitation therapy and it provides the electrical activity produced by skeletal muscles. Among the parameters measured with EMG, two very important quantities are: signal amplitude and duration of muscle contraction, muscle fatigue and maximum muscle power. Recently, a new measurement procedure, named Laser Doppler Myography (LDMi), for the non contact assessment of muscle activity has been proposed to measure the vibro-mechanical behaviour of the muscle. The aim of this study is to present the LDMi technique and to evaluate its capacity to measure some characteristic features proper of the muscle. In this paper LDMi is compared with standard superficial EMG (sEMG) requiring the application of sensors on the skin of each patient. sEMG and LDMi signals have been simultaneously acquired and processed to test correlations. Three parameters has been analyzed to compare these techniques: Muscle activation timing, signal amplitude and muscle fatigue. LDMi appears to be a reliable and promising measurement technique allowing the measurements without contact with the patient skin

  17. Doppler-Resolved Kinetics of Saturation Recovery.

    Science.gov (United States)

    Forthomme, Damien; Hause, Michael L; Yu, Hua-Gen; Dagdigian, Paul J; Sears, Trevor J; Hall, Gregory E

    2015-07-16

    Frequency-modulated laser transient absorption has been used to monitor the ground-state rotational energy-transfer rates of CN radicals in a double-resonance, depletion recovery experiment. When a pulsed laser is used to burn a hole in the equilibrium ground-state population of one rotational state without velocity selection, the population recovery rate is found to depend strongly on the Doppler detuning of a narrow-band probe laser. Similar effects should be apparent for any relaxation rate process that competes effectively with velocity randomization. Alternative methods of extracting thermal rate constants in the presence of these non-thermal conditions are evaluated. Total recovery rate constants, analogous to total removal rate constants in an experiment preparing a single initial rotational level, are in good agreement with quantum scattering calculations, but are slower than previously reported experiments and show qualitatively different rotational state dependence between Ar and He collision partners. Quasi-classical trajectory studies confirm that the differing rotational state dependence is primarily a kinematic effect. PMID:25815527

  18. Analysis of Radar Doppler Signature from Human Data

    Directory of Open Access Journals (Sweden)

    M. ANDRIĆ

    2014-04-01

    Full Text Available This paper presents the results of time (autocorrelation and time-frequency (spectrogram analyses of radar signals returned from the moving human targets. When a radar signal falls on the human target which is moving toward or away from the radar, the signals reflected from different parts of his body produce a Doppler shift that is proportional to the velocity of those parts. Moving parts of the body causes the characteristic Doppler signature. The main contribution comes from the torso which causes the central Doppler frequency of target. The motion of arms and legs induces modulation on the returned radar signal and generates sidebands around the central Doppler frequency, referred to as micro-Doppler signatures. Through analyses on experimental data it was demonstrated that the human motion signature extraction is better using spectrogram. While the central Doppler frequency can be determined using the autocorrelation and the spectrogram, the extraction of the fundamental cadence frequency using the autocorrelation is unreliable when the target is in the clutter presence. It was shown that the fundamental cadence frequency increases with increasing dynamic movement of people and simultaneously the possibility of its extraction is proportional to the degree of synchronization movements of persons in the group.

  19. One-way Doppler extractor. [for positions of orbiting vehicles

    Science.gov (United States)

    Nossen, E. J.; Starner, E. R.

    1977-01-01

    This paper presents a feasibility analysis, tradeoffs, and implementation for a one-way Doppler extractor system. A Doppler error analysis is discussed which shows that quantization error is a primary source of Doppler measurement error. Several competing extraction techniques are compared, and a 'Vernier' technique is presented which obtains high Doppler resolution with low-speed logic. Parameter tradeoffs and sensitivities for this Vernier technique are discussed, leading to a hardware design configuration. Also presented is a performance evaluation of the resulting breadboard model that verifies the theoretical performance predictions. The breadboard model contains the circuitry to interface with an S-band transponder, to extract the Doppler and time-interval counts, to compute navigational parameters by means of a microprocessor, and to display the results. Performance tests have verified that the breadboard is capable of extracting Doppler, on an S-band signal, to an accuracy of better than 0.02 hertz for a one-second averaging period. This corresponds to a range rate error of no more than 3 millimeters per second.

  20. Low-Frequency Gravitational Wave Searches Using Spacecraft Doppler Tracking

    Directory of Open Access Journals (Sweden)

    Armstrong J. W.

    2006-01-01

    Full Text Available This paper discusses spacecraft Doppler tracking, the current-generation detector technology used in the low-frequency (~millihertz gravitational wave band. In the Doppler method the earth and a distant spacecraft act as free test masses with a ground-based precision Doppler tracking system continuously monitoring the earth-spacecraft relative dimensionless velocity $2 Delta v/c = Delta u/ u_0$, where $Delta u$ is the Doppler shift and $ u_0$ is the radio link carrier frequency. A gravitational wave having strain amplitude $h$ incident on the earth-spacecraft system causes perturbations of order $h$ in the time series of $Delta u/ u_0$. Unlike other detectors, the ~1-10 AU earth-spacecraft separation makes the detector large compared with millihertz-band gravitational wavelengths, and thus times-of-flight of signals and radio waves through the apparatus are important. A burst signal, for example, is time-resolved into a characteristic signature: three discrete events in the Doppler time series. I discuss here the principles of operation of this detector (emphasizing transfer functions of gravitational wave signals and the principal noises to the Doppler time series, some data analysis techniques, experiments to date, and illustrations of sensitivity and current detector performance. I conclude with a discussion of how gravitational wave sensitivity can be improved in the low-frequency band.

  1. Doppler Monitoring of the WASP-47 Multiplanet System

    Science.gov (United States)

    Dai, Fei; Winn, Joshua N.; Arriagada, Pamela; Butler, R. Paul; Crane, Jeffrey D.; Johnson, John Asher; Shectman, Stephen A.; Teske, Johanna K.; Thompson, Ian B.; Vanderburg, Andrew; Wittenmyer, Robert A.

    2015-11-01

    We present precise Doppler observations of WASP-47, a transiting planetary system featuring a hot Jupiter with both inner and outer planetary companions. This system has an unusual architecture and also provides a rare opportunity to measure planet masses in two different ways: the Doppler method, and the analysis of transit-timing variations (TTV). Based on the new Doppler data, obtained with the Planet Finder Spectrograph on the Magellan/Clay 6.5 m telescope, the mass of the hot Jupiter is 370+/- 29 {M}\\oplus . This is consistent with the previous Doppler determination as well as the TTV determination. For the inner planet WASP-47e, the Doppler data lead to a mass of 12.2+/- 3.7 {M}\\oplus , in agreement with the TTV-based upper limit of WASP-47d, the Doppler mass constraint of 10.4+/- 8.4 {M}\\oplus is consistent with the TTV-based measurement of {15.2}-7.6+6.7 {M}\\oplus . This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.

  2. Doppler Monitoring of the WASP-47 Multiplanet System

    CERN Document Server

    Dai, Fei; Arriagada, Pamela; Butler, R Paul; Crane, Jeffrey D; Johnson, John Asher; Shectman, Stephen A; Teske, Johanna K; Thompson, Ian B; Vanderburg, Andrew; Wittenmyer, Robert A

    2015-01-01

    We present precise Doppler observations of WASP-47, a transiting planetary system featuring a hot Jupiter with both inner and outer planetary companions. This system has an unusual architecture and also provides a rare opportunity to measure planet masses in two different ways: the Doppler method, and the analysis of transit-timing variations (TTV). Based on the new Doppler data, obtained with the Planet Finder Spectrograph on the Magellan/Clay 6.5m telescope, the mass of the hot Jupiter is $370 \\pm 29~M_{\\oplus}$. This is consistent with the previous Doppler determination as well as the TTV determination. For the inner planet WASP-47e, the Doppler data lead to a mass of $12.2\\pm 3.7~ M_{\\oplus}$, in agreement with the TTV-based upper limit of $<$22~$M_{\\oplus}$ ($95\\%$ confidence). For the outer planet WASP-47d, the Doppler mass constraint of $10.4\\pm 8.4~M_{\\oplus}$ is consistent with the TTV-based measurement of $15.2^{+6.7}_{-7.6}~ M_{\\oplus}$.

  3. Atratividade de adultos de Chrysoperla externa (Hagen, 1861 aos compostos voláteis de coentro, endro e erva-doce (Apiaceae em condições de laboratório

    Directory of Open Access Journals (Sweden)

    André Luis Santos Resende

    2015-02-01

    Full Text Available Espécies de Apiaceae dispõem de óleos essenciais, nos quais podem ocorrer compostos voláteis, que funcionam como sinais para atração e manutenção de inimigos naturais nas áreas cultivadas. Com base nestas características, este trabalho objetivou avaliar a atratividade aos adultos do predador Chrysoperla externa. Foram utilizados folhas e caules de coentro, endro e erva-doce, coletados aos 30 e 60 dias após a semeadura. As plantas foram dispostas em olfatômetro de quatro vias (formato de "X" disponibilizando-se os odores para machos e fêmeas, virgens e acasalados, em testes de livre escolha. Ao serem liberados individualmente no interior do olfatômetro, foram cronometrados cinco minutos e contabilizado o tempo total de permanência do inseto em cada braço do aparelho. Os dados foram analisados pelo teste c², com frequência esperada de 25%. Estudou-se o rendimento de óleo essencial das três espécies de plantas, 30 e 60 dias após a semeadura, utilizando-se do método de hidrodestilação. A composição química dos óleos foi determinada por cromatografia gasosa acoplada a espectrômetro de massas. Verificou-se que adultos virgens têm preferência por plantas de coentro, enquanto os acasalados preferem plantas de erva-doce, ambas coletadas aos 30 dias. Plantas com 60 dias não proporcionaram resposta atrativa aos adultos de C. externa. O rendimento de óleo tendeu a aumentar com o desenvolvimento fenológico da planta. A composição química do óleo de coentro revelou, como componentes majoritários, o (2E-decenal e decanal e, para erva-doce, a maior concentração foi de (E-anetol.

  4. Single Mode, Extreme Precision Doppler Spectrographs

    Science.gov (United States)

    Schwab, Christian; Leon-Saval, Sergio G.; Betters, Christopher H.; Bland-Hawthorn, Joss; Mahadevan, Suvrath

    2014-04-01

    The `holy grail' of exoplanet research today is the detection of an earth-like planet: a rocky planet in the habitable zone around a main-sequence star. Extremely precise Doppler spectroscopy is an indispensable tool to find and characterize earth-like planets; however, to find these planets around solar-type stars, we need nearly one order of magnitude better radial velocity (RV) precision than the best current spectrographs provide. Recent developments in astrophotonics (Bland-Hawthorn & Horton 2006, Bland-Hawthorn et al. 2010) and adaptive optics (AO) enable single mode fiber (SMF) fed, high resolution spectrographs, which can realize the next step in precision. SMF feeds have intrinsic advantages over multimode fiber or slit coupled spectrographs: The intensity distribution at the fiber exit is extremely stable, and as a result the line spread function of a well-designed spectrograph is fully decoupled from input coupling conditions, like guiding or seeing variations (Ihle et al. 2010). Modal noise, a limiting factor in current multimode fiber fed instruments (Baudrand & Walker 2001), can be eliminated by proper design, and the diffraction limited input to the spectrograph allows for very compact instrument designs, which provide excellent optomechanical stability. A SMF is the ideal interface for new, very precise wavelength calibrators, like laser frequency combs (Steinmetz et al. 2008, Osterman et al. 2012), or SMF based Fabry-Perot Etalons (Halverson et al. 2013). At near infrared wavelengths, these technologies are ready to be implemented in on-sky instruments, or already in use. We discuss a novel concept for such a spectrograph.

  5. Hands-Free Transcranial Color Doppler Probe

    Science.gov (United States)

    Chin, Robert; Madala, Srihdar; Sattler, Graham

    2012-01-01

    Current transcranial color Doppler (TCD) transducer probes are bulky and difficult to move in tiny increments to search and optimize TCD signals. This invention provides miniature motions of a TCD transducer probe to optimize TCD signals. The mechanical probe uses a spherical bearing in guiding and locating the tilting crystal face. The lateral motion of the crystal face as it tilts across the full range of motion was achieved by minimizing the distance between the pivot location and the crystal face. The smallest commonly available metal spherical bearing was used with an outer diameter of 12 mm, a 3-mm tall retaining ring, and 5-mm overall height. Small geared motors were used that would provide sufficient power in a very compact package. After confirming the validity of the basic positioning concept, optimization design loops were completed to yield the final design. A parallel motor configuration was used to minimize the amount of space wasted inside the probe case while minimizing the overall case dimensions. The distance from the front edge of the crystal to the edge of the case was also minimized to allow positioning of the probe very close to the ear on the temporal lobe. The mechanical probe is able to achieve a +/-20deg tip and tilt with smooth repeatable action in a very compact package. The enclosed probe is about 7 cm long, 4 cm wide, and 1.8 cm tall. The device is compact, hands-free, and can be adjusted via an innovative touchscreen. Positioning of the probe to the head is performed via conventional transducer gels and pillows. This device is amendable to having advanced software, which could intelligently focus and optimize the TCD signal.

  6. Longitudinal study of aortic isthmus Doppler in appropriately grown and small-for-gestational-age fetuses with normal and abnormal umbilical artery Doppler.

    LENUS (Irish Health Repository)

    Kennelly, M M

    2012-04-01

    To establish reference ranges using longitudinal data for aortic isthmus (AoI) Doppler indices in appropriate-for-gestational-age (AGA) fetuses and to document the longitudinal trends in a cohort of small-for-gestational-age (SGA) fetuses with normal umbilical artery Doppler and in fetuses with intrauterine growth restriction (IUGR) and abnormal umbilical artery Doppler.

  7. Comparison between oscillometric- and Doppler-ABI in elderly individuals

    Directory of Open Access Journals (Sweden)

    Takahashi I

    2013-03-01

    Full Text Available Ikuno Takahashi,1,3 Kyoji Furukawa,2 Waka Ohishi,1 Tetsuya Takahashi,3 Masayasu Matsumoto,3 Saeko Fujiwara11Department of Clinical Studies, 2Department of Statistics, Radiation Effects Research Foundation (RERF, Hiroshima, Japan; 3Department of Clinical Neuroscience and Therapeutics, Hiroshima University, Hiroshima, JapanAbstract: Peripheral arterial disease (PAD generally remains under-recognized, mainly due to the specialized technical skills required to detect the low values of the ankle-brachial index (ABI. As a simpler and faster alternative to the standard method using continuous-wave Doppler ultrasound, we evaluated automated oscillometric ABI measurement by VP-2000 with an elderly cohort of 113 subjects (age range, 61 to 88 years. The standard deviation in ABIs measured by the Doppler method was statistically greater than that measured by the oscillometric method for each of the two legs (P < 0.001. Correlations in ABIs between the two methods were 0.46 for the left leg and 0.61 for the right leg; this result appears to have been caused by interobserver variation in the Doppler ABI measurements. While the trend showing greater differences between average oscillometric- and Doppler-ABIs was significant at the lower ABI ranges, there was little indication of differences in measurements having an average ABI > 1.1. The difference between the methods was suggestively larger in subjects who were smokers than in non-smokers (P = 0.09, but the difference was not affected by other potential atherosclerotic risk factors, including age at examination (P > 0.50. A larger difference at lower ABIs led to better PAD detection by the Doppler method compared to the oscillometric method (sensitivity = 50%, specificity = 100%, although the overall agreement was not small (Cohen's Kappa = 0.65. Our findings indicate that oscillometric devices can provide more accurate estimation of the prevalence of PAD in elderly individuals than the conventional Doppler method.Keywords: ankle-brachial index, oscillometry, Doppler, peripheral arterial disease

  8. DOPPLER SIGNATURES OF THE ATMOSPHERIC CIRCULATION ON HOT JUPITERS

    International Nuclear Information System (INIS)

    The meteorology of hot Jupiters has been characterized primarily with thermal measurements, but recent observations suggest the possibility of directly detecting the winds by observing the Doppler shift of spectral lines seen during transit. Motivated by these observations, we show how Doppler measurements can place powerful constraints on the meteorology. We show that the atmospheric circulation—and Doppler signature—of hot Jupiters splits into two regimes. Under weak stellar insolation, the day-night thermal forcing generates fast zonal jet streams from the interaction of atmospheric waves with the mean flow. In this regime, air along the terminator (as seen during transit) flows toward Earth in some regions and away from Earth in others, leading to a Doppler signature exhibiting superposed blueshifted and redshifted components. Under intense stellar insolation, however, the strong thermal forcing damps these planetary-scale waves, inhibiting their ability to generate jets. Strong frictional drag likewise damps these waves and inhibits jet formation. As a result, this second regime exhibits a circulation dominated by high-altitude, day-to-night airflow, leading to a predominantly blueshifted Doppler signature during transit. We present state-of-the-art circulation models including non-gray radiative transfer to quantify this regime shift and the resulting Doppler signatures; these models suggest that cool planets like GJ 436b lie in the first regime, HD 189733b is transitional, while planets hotter than HD 209458b lie in the second regime. Moreover, we show how the amplitude of the Doppler shifts constrains the strength of frictional drag in the upper atmospheres of hot Jupiters. If due to winds, the ?2 km s–1 blueshift inferred on HD 209458b may require drag time constants as short as 104-106 s, possibly the result of Lorentz-force braking on this planet's hot dayside.

  9. Doppler ultrasound imaging techniques for assessment of synovial inflammation

    Directory of Open Access Journals (Sweden)

    Filippucci E

    2013-09-01

    Full Text Available Emilio Filippucci,1 Fausto Salaffi,1 Marina Carotti,2 Walter Grassi1 1Rheumatology Department, Polytechnic University of the Marche, Ancona, Italy; 2Department of Radiology, Polytechnic University of the Marche, Ancona, Italy Abstract: Ultrasound is an evolving technique, and the rapid progress made in ultrasound technology over the past ten years has dramatically increased its range of applications in rheumatology. One of the most exciting advances is the use of Doppler ultrasound imaging in the assessment of blood flow abnormalities at the synovial tissue level in patients with chronic inflammatory arthritis. This review describes the Doppler techniques available and their main applications in patients with inflammatory arthritis, discusses the evidence supporting their use, and outlines the latest advances in hardware and software. Spectral, color, and power Doppler allow sensitive assessment of vascular abnormalities at the synovial tissue level. Use of contrast agents enhances visualization of the small synovial vessels using color or power Doppler ultrasound and allows for accurate characterization of the rheumatoid pannus. Doppler techniques represent a unique method for assessment of synovial inflammation, showing blood flow characteristics in real time. They are safe, noninvasive, cost-effective, and have high sensitivity in revealing and monitoring synovitis. However, several questions still need to be answered. In the near future, the Doppler techniques described here, together with upcoming hardware and software facilities, will be investigated further and a consensus will be reached on their feasibility and appropriate use in daily rheumatologic practice. Keywords: power and color Doppler techniques, ultrasound, contrast media, synovitis, rheumatoid arthritis

  10. Cross-correlation Doppler global velocimetry (CC-DGV)

    Science.gov (United States)

    Cadel, Daniel R.; Lowe, K. Todd

    2015-08-01

    A flow velocimetry method, cross-correlation Doppler global velocimetry (CC-DGV), is presented as a robust, simplified, and high dynamic range implementation of the Doppler global/planar Doppler velocimetry technique. A sweep of several gigahertz of the vapor absorption spectrum is used for each velocity sample, with signals acquired from both Doppler-shifted scattered light within the flow and a non-Doppler shifted reference beam. Cross-correlation of these signals yields the Doppler shift between them, averaged over the duration of the scan. With presently available equipment, velocities from 0 ms-1 to over 3000 ms-1 can notionally be measured simultaneously, making the technique ideal for high speed flows. The processing routine is shown to be robust against large changes in the vapor pressure of the iodine cell, benefiting performance of the system in facilities where ambient conditions cannot be easily regulated. Validation of the system was performed with measurements of a model wind turbine blade boundary layer made in a 1.83 m by 1.83 m subsonic wind tunnel for which laser Doppler velocimetry (LDV) measurements were acquired alongside the CC-DGV results. CC-DGV uncertainties of ±1.30 ms-1, ±0.64 ms-1, and ±1.11 ms-1 were determined for the orthogonal stream-wise, transverse-horizontal, and transverse-vertical velocity components, and root-mean-square deviations of 2.77 ms-1 and 1.34 ms-1 from the LDV validation results were observed for Reynolds numbers of 1.5 million and 2 million, respectively. Volumetric mean velocity measurements are also presented for a supersonic jet, with velocity uncertainties of ±4.48 ms-1, ±16.93 ms-1, and ±0.50 ms-1 for the orthogonal components, and self-validation done by collapsing the data with a physical scaling.

  11. Doppler Signatures of the Atmospheric Circulation on Hot Jupiters

    Science.gov (United States)

    Showman, Adam P.; Fortney, Jonathan J.; Lewis, Nikole K.; Shabram, Megan

    2013-01-01

    The meteorology of hot Jupiters has been characterized primarily with thermal measurements, but recent observations suggest the possibility of directly detecting the winds by observing the Doppler shift of spectral lines seen during transit. Motivated by these observations, we show how Doppler measurements can place powerful constraints on the meteorology. We show that the atmospheric circulation—and Doppler signature—of hot Jupiters splits into two regimes. Under weak stellar insolation, the day-night thermal forcing generates fast zonal jet streams from the interaction of atmospheric waves with the mean flow. In this regime, air along the terminator (as seen during transit) flows toward Earth in some regions and away from Earth in others, leading to a Doppler signature exhibiting superposed blueshifted and redshifted components. Under intense stellar insolation, however, the strong thermal forcing damps these planetary-scale waves, inhibiting their ability to generate jets. Strong frictional drag likewise damps these waves and inhibits jet formation. As a result, this second regime exhibits a circulation dominated by high-altitude, day-to-night airflow, leading to a predominantly blueshifted Doppler signature during transit. We present state-of-the-art circulation models including non-gray radiative transfer to quantify this regime shift and the resulting Doppler signatures; these models suggest that cool planets like GJ 436b lie in the first regime, HD 189733b is transitional, while planets hotter than HD 209458b lie in the second regime. Moreover, we show how the amplitude of the Doppler shifts constrains the strength of frictional drag in the upper atmospheres of hot Jupiters. If due to winds, the ~2 km s-1 blueshift inferred on HD 209458b may require drag time constants as short as 104-106 s, possibly the result of Lorentz-force braking on this planet's hot dayside.

  12. Doppler Signatures of the Atmospheric Circulation of Hot Jupiters

    Science.gov (United States)

    Showman, Adam P.; Fortney, J. J.; Lewis, N. K.; Shabram, M.

    2011-09-01

    To date, the exotic meteorology of hot Jupiters has primarily been characterized with thermal measurements, providing only indirect clues to the wind regime. Recently, however, Snellen et al. (2010) presented high-resolution groundbased transit spectra of HD209458b containing an apparent 2 km/sec blueshift, which they interpreted as a signature of atmospheric winds flowing from dayside to nightside toward Earth along the planet's terminator. Motivated by these observations, we describe the types of Doppler signatures generated by the atmospheric circulation and show how Doppler measurements can place powerful constraints on the meteorology. We show that, depending on parameters, the atmospheric circulation--and Doppler signature--of hot Jupiters splits into two regimes. At moderate stellar insolation, the day-night thermal forcing generates fast east-west jet streams from the interaction of standing planetary-scale waves with the mean flow. In this regime, air along the terminator (as seen during transit) flows toward Earth in some regions and away from Earth in others, leading to a bimodal Doppler signature exhibiting distinct, superposed blue- and redshifted velocity peaks. Under more intense stellar insolation, however, the thermal forcing is so strong that it damps these planetary-scale waves, inhibiting their ability to generate jet streams. As a result, this second regime exhibits a circulation dominated primarily by high-altitude, day-to-night airflow along both terminators rather than longitudinally symmetric jets. This causes air to flow toward Earth along most of the terminator, leading to a predominantly blueshifted Doppler signature during transit. We present state-of-the-art 3D circulation models including nongrey radiative transfer to quantify this regime shift and the resulting Doppler signatures; these models suggest that HD189733b lies in the first regime while HD209458b lies in the second regime. Moreover, we show how the amplitude of the Doppler shifts place strong constraints on the strength of frictional drag in the upper atmospheres of hot Jupiters.

  13. Doppler broadening induced spectral shift effects on reactor safety

    International Nuclear Information System (INIS)

    It is commonly accepted that the resonance reaction rate of any material increases when the temperature is raised. However, in a nuclear reactor the increase in resonance reaction rates with temperature at relatively high energy shifts the neutron spectrum in such a way that a net decrease in the neutron flux results at lower energies. This finding suggested that the spectral shift could significantly affect the Doppler reactivity change, warranting further investigations. The objective was to study the physical characteristics of this new phenomenon and its effects on reactor safety. The desirability of studying this effect was strengthened by the presence of discrepancies between the calculated and measured integral experiments. An exact Doppler broadening kernel, based on the Maxwellian distribution of nuclear velocities, and an accurate integral transport method NDCRAB, capable of including resonance overlap of all materials present in the reactor cell, were used in this study. The ZPR-6 Assembly 7 benchmark, a typical LMFBR reactor, was used to quantify the Doppler reactivity change for an increase in fuel temperature and to analyze the natural UO3 sample Doppler worth in this assembly. The quantification of the various components of the Doppler reactivity change shows that the fissile material, 239Pu, has a large negative Doppler effect and contributes a large fraction to the total negative effect. The calculated Doppler effect of the natural UO3 sample in this assembly was in good agreement with the measured value. The calculated and measured values for an increase in sample temperature from 293-0K to 11000K wre -0.887 Ih/kgU and -0.868 Ih/kgU

  14. Re-Normalization Method of Doppler Lidar Signal for Error Reduction

    International Nuclear Information System (INIS)

    In this paper, we presented a re-normalization method for the fluctuations of Doppler signals from the various noises mainly due to the frequency locking error for a Doppler lidar system. For the Doppler lidar system, we used an injection-seeded pulsed Nd:YAG laser as the transmitter and an iodine filter as the Doppler frequency discriminator. For the Doppler frequency shift measurement, the transmission ratio using the injection-seeded laser is locked to stabilize the frequency. If the frequency locking system is not perfect, the Doppler signal has some error due to the frequency locking error. The re-normalization process of the Doppler signals was performed to reduce this error using an additional laser beam to an Iodine cell. We confirmed that the renormalized Doppler signal shows the stable experimental data much more than that of the averaged Doppler signal using our calibration method, the reduced standard deviation was 4.838 Χ 10-3

  15. Re-Normalization Method of Doppler Lidar Signal for Error Reduction

    Energy Technology Data Exchange (ETDEWEB)

    Park, Nakgyu; Baik, Sunghoon; Park, Seungkyu; Kim, Donglyul [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Kim, Dukhyeon [Hanbat National Univ., Daejeon (Korea, Republic of)

    2014-05-15

    In this paper, we presented a re-normalization method for the fluctuations of Doppler signals from the various noises mainly due to the frequency locking error for a Doppler lidar system. For the Doppler lidar system, we used an injection-seeded pulsed Nd:YAG laser as the transmitter and an iodine filter as the Doppler frequency discriminator. For the Doppler frequency shift measurement, the transmission ratio using the injection-seeded laser is locked to stabilize the frequency. If the frequency locking system is not perfect, the Doppler signal has some error due to the frequency locking error. The re-normalization process of the Doppler signals was performed to reduce this error using an additional laser beam to an Iodine cell. We confirmed that the renormalized Doppler signal shows the stable experimental data much more than that of the averaged Doppler signal using our calibration method, the reduced standard deviation was 4.838 ? 10{sup -3}.

  16. Renal Power Doppler Ultrasonographic Evaluation of Children With Acute Pyelonephritis

    Directory of Open Access Journals (Sweden)

    Ali Pahlusi

    2011-10-01

    Full Text Available Urinary tract infections are common in children. The available gold standard method for diagnosis, Tc-99m dimercaptosuccinic acid scan is expensive and exposes patients to considerable amount of radiation. This study was performed to compare and assess the efficacy of Power Doppler Ultrasound versus Tc-99m DMSA scan for diagnosis of acute pyelonephritis. A quasi experimental study was conducted on 34 children with mean age of 2.8?2.7 years who were hospitalized with their first episode of febrile urinary tract infection. All children were evaluated in the first 3 days of admission by Doppler Ultrasound and Tc-99m DMSA scan. Patients with congenital structural anomalies were excluded. Each kidney was divided into three zones. The comparison between efficacy of Doppler Ultrasound and DMSA scan was carried out based on number of patients and on classified renal units. Based on the number of patients enrolled; the sensitivity, specificity, positive and negative predictive values and accuracy of Doppler Ultrasound were 89%, 53%, 70%, 80% and 74%, respectively but based on the renal units, it was 66%, 81%, 46%, 91% and 79% , respectively. Although Doppler Ultrasound has the potential for identifying acute pyelonephritis in children, but it is still soon to replace DMSA scan.

  17. Blood flow measurement by laser Doppler method in orofacial region

    Directory of Open Access Journals (Sweden)

    Grga ?urica

    2010-01-01

    Full Text Available Laser Doppler is a noninvasive, objective, reproducible and painless method for measuring blood flow in tissue microcirculation. This method is based on the Doppler effect, the change in frequency of light reflecting from blood cells in motion. Light from helium-neon laser through optical fibers and probes is directed to the surface of the tissue in which the flow is measured. Light portion is reflected from the cells in motion and changes the frequency while another portion is reflected from the static tissue maintaining the same frequency as the initial light. The total reflected light, with changed and original frequency, reaches photo detector in the same probe where the emitter is and it is transformed into electrical impulse. In the orofacial region the laser Doppler method is used to examine blood flow in the mandible, teeth pulp and masticator muscles. A significant drawback of the laser Doppler method is its sensitivity to the ambient conditions during measuring and the fact that blood flow is measured in all blood vessels of examined microregion. Therefore, the circulation of isolated individual blood vessels can not be monitored. Laser Doppler method can give reliable indicators of blood flow in mouth tissue and method is acceptable for the patients.

  18. Doppler ultrasonographic imaging of obstruction of inferior vena cava

    International Nuclear Information System (INIS)

    Budd-Chiari syndrome is a rare condition caused by hepatic venous outflow obstruction. Although liver biopsy and venography have been considered to be conclusive in the diagnosis of Budd-Chiari syndrome, those procedures involve a great deal of disecomfort and risk for the patient. As the recently developed Doppler ultrasonography is able to define the direction of blood flow and measure the blood flow velocity and volume in the portal vein, inferior vena cava(IVC) and hepatic vein, it can be used in the diagnosis of Budd-Chiari syndrome. We analyzed Doppler ultrasonographic findings in two patients with membraneous obstruction of the IVC, suspected from Doppler ultrasonographic findings and confirmed by venocavography. Doppler ultrasonography demonstrated reversed laminar flow on inspiration and no significant flow on expiration in the dilated IVC proximal to the stenosis and turbulent flow in the proximal portion of the stenosis. After balloon dilatation, the flow was changed and directed normally. These findings correlated very well with venocavographic findings. Our results suggest that Doppler ultrasonography is a simple, non-invasive and effective method for the initial evaluation of patients suspected of having obstruction of the IVC and the evaluation of therapeutic effect

  19. Doppler Uterine Artery Flow Velocimetry in Prediction of Preterm Labor

    Directory of Open Access Journals (Sweden)

    Mahyar Mohammadi Fard

    2009-01-01

    Full Text Available "nIntroduction: To evaluate the role of Doppler waveforms of the uterine vessels in predicting preterm labor. "nMaterials and Methods: This was a retrospective analysis of the uterine artery Doppler findings of 28 15-25 week singleton pregnancies with a spontaneous preterm labor were compared to 326 pregnancies delivered at term. 354 women who presented to our medical center from April 20, 2008 to November 20, 2008 were enrolled in the study. Pulsed-wave Doppler measurements were made of the maternal uterine arteries. These women were followed up until delivery. "nResults: The uterine artery mean resistance index (RI was 0.76 and 0.66 in the preterm and term delivery groups, respectively (P < 0.05. Bilateral diastolic notches were present in 41% of the preterm deliveries and 27% of the controls (P < 0.05. The mean pulsatility index (PI was 1.40 and 1.83 (46% in the term and preterm delivery groups, respectively (P < 0.05. "nConclusion: Doppler of the uterine vessels could prove to be a good predictor of preterm labor. "nKey words: premature labor, prenatal diagnosis, uterus blood supply, pregnancy, ultrasound, color Doppler.  

  20. Ovarian and uterine periovulatory Doppler ultrasonography in bitches / Ultrassonografia Doppler ovariana e uterina em cadelas

    Scientific Electronic Library Online (English)

    Claudia C., Barbosa; Mírley B., Souza; Sarah R.R.A., Scalercio; Ticiana F.P., Silva; Sheyla F.S., Domingues; Lúcia D.M., Silva.

    2013-09-01

    Full Text Available Este trabalho teve como objetivo descrever as características ultrassonográficas uterinas e ovarianas, e dopplervelocimétricas das suas artérias nos dias periovulatórios em cadelas. Quinze ciclos estrais em 10 animais foram avaliados. As características ultrassonográficas, índices de resistência (IR [...] ) e índices de pulsatilidade (IP) do útero e dos ovários em cada animal foram registrados 5 dias antes e depois da ovulação (D0). Os dados foram analisados estatisticamente e os resultados foram expressos em média ± erro padrão da média (P Abstract in english This paper aims to describe the uterine and ovarian ultrasonographic characteristics and Doppler velocimetric features of their arteries in bitches during the periovulatory period. Fifteen estrous cycles in 10 animals were evaluated. The ultrasonographic characteristics, resistance indices (RI) and [...] pulsatility indices (PI) of the uterus and ovaries in each animal were recorded 5 days before and after ovulation (D0). The data were statistically analyzed, and the results were expressed as the mean ± standard error of mean (P

  1. Three-dimensional laser cooling at the Doppler limit

    CERN Document Server

    Chang, Rockson; Bouton, Quentin; Fang, Yami; Klafka, Tobias; Audo, Kevin; Aspect, Alain; Westbrook, Christoph I; Clément, David

    2014-01-01

    Many predictions of the theory of Doppler cooling of 2-level atoms, notably the celebrated minimum achievable temperature $T_D=\\hbar \\Gamma/2 k_B$, have never been verified in a three-dimensional geometry. Here, we show that, despite their degenerate level structure, we can use Helium-4 atoms to achieve a situation in which these predictions can be verified. We make measurements of atomic temperatures, magneto-optical trap sizes, and the sensitivity of optical molasses to a power imbalance in the laser beams, finding excellent agreement with the Doppler theory. We show that the special properties of Helium, particularly its small mass and narrow transition linewidth, prevent effective sub-Doppler cooling with red-detuned optical molasses.

  2. Non-intrusive Shock Measurements Using Laser Doppler Vibrometers

    Science.gov (United States)

    Statham, Shannon M.; Kolaini, Ali R.

    2012-01-01

    Stud mount accelerometers are widely used by the aerospace industry to measure shock environments during hardware qualification. The commonly used contact-based sensors, however, interfere with the shock waves and distort the acquired signature, which is a concern not actively discussed in the community. To alleviate these interference issues, engineers at the Jet Propulsion Laboratory are investigating the use of non-intrusive sensors, specifically Laser Doppler Vibrometers, as alternatives to the stud mounted accelerometers. This paper will describe shock simulation tests completed at the Jet Propulsion Laboratory, compare the measurements from stud mounted accelerometers and Laser Doppler Vibrometers, and discuss the advantages and disadvantages of introducing Laser Doppler Vibrometers as alternative sensors for measuring shock environments.

  3. Sensor system for metallic targets including doppler radar and radiometer

    Energy Technology Data Exchange (ETDEWEB)

    Lindner, K.

    1985-04-16

    In a sensor system including Doppler radar, a radiometer and circuits for comparing the target information received by the two devices, a receiving mixer comprising a mixer oscillator is employed both for transmitting the CW Doppler radar emission signal and for transforming the frequency of the returning radar echo and radiometer signal. At the output of the mixer, the Doppler signal is obtained as a low-frequency signal and the radiometer signal as an IF signal, so that both can easily be separated and individually processed. The radiometer signal is checked only for a jump in the noise temperature. With such a jump present and if simultaneously a radar target is detected, the presence of a metallic target is inferred.

  4. A Human Gait Classification Method Based on Radar Doppler Spectrograms

    Directory of Open Access Journals (Sweden)

    Amin MoenessG

    2010-01-01

    Full Text Available An image classification technique, which has recently been introduced for visual pattern recognition, is successfully applied for human gait classification based on radar Doppler signatures depicted in the time-frequency domain. The proposed method has three processing stages. The first two stages are designed to extract Doppler features that can effectively characterize human motion based on the nature of arm swings, and the third stage performs classification. Three types of arm motion are considered: free-arm swings, one-arm confined swings, and no-arm swings. The last two arm motions can be indicative of a human carrying objects or a person in stressed situations. The paper discusses the different steps of the proposed method for extracting distinctive Doppler features and demonstrates their contributions to the final and desirable classification rates.

  5. Spaceborne Doppler Precipitation Radar: System Configurations and Performance Analysis

    Science.gov (United States)

    Tanelli, Simone; Im, Eastwood

    2004-01-01

    Knowledge of the global distribution of the vertical velocity of precipitation is important in in the study of energy transportation in the atmosphere, the climate and weather. Such knowledge can only be directly acquired with the use of spaceborne Doppler precipitation radars. Although the high relative speed of the radar with respect to the rainfall particles introduces significant broadening in the Doppler spectrum, recent studies have shown that the average vertical velocity can be measured to acceptable accuracy levels by appropriate selection of radar parameters. Furthermore, methods to correct for specific errors arising from NUBF effects and pointing uncertainties have recently been developed. In this paper we will present the results of the trade studies on the performances of a spaceborne Doppler radar with different system parameters configurations.

  6. Color Doppler imaging of the eye and orbit.

    Science.gov (United States)

    Lieb, W E

    1998-11-01

    Since the development of A- and B-scan ultrasound technique in the 1950s, significant progress in ophthalmic ultrasound has appeared. As the technology advances and ultrasound systems improve their ability to acquire and detect ultrasonic signals and to analyze them in terms of a spatial resolution and frequency distribution, there is no doubt that the extent of clinical applications will expand accordingly. Nevertheless, the fundamental physical restrictions of ultrasonography and Doppler will always remain the same. For ophthalmology, we hope that less expensive color Doppler systems with specifically designed probes, improved two-dimensional resolution, and Doppler spectrum acquisition will become more widely available. Because CDI allows for the first time a noninvasive assessment of the retrobulbar vasculature, we feel that many applications of this technology will develop for ophthalmology. PMID:9884688

  7. Development of Dual Beam High Speed Doppler OFD

    Energy Technology Data Exchange (ETDEWEB)

    Park, Tae Jin; Oh, Wang Yuhl [Dept. of Mechanical Engineering, Korea Advance Institute of Science and Technology, Daejeon (Korea, Republic of); Kim, Sun Hee [Korea Railroad Research Institute, Uiwang (Korea, Republic of)

    2013-06-15

    This paper describes development of a high speed Doppler OFDI system for non-invasive vascular imaging. Doppler OFDI (optical frequency domain imaging) is one of the phase-resolved second generation OCT (optical coherence tomography) techniques for high resolution imaging of moving elements in biological tissues. To achieve a phase-resolved imaging, two temporally separated measurements are required. In a conventional Doppler OCT, a pair of massively oversampled successive A-lines is used to minimize de-correlation noise at the expense of significant imaging speed reduction. To minimize a de-correlation noise between targeted two measurements without suffering from significant imaging speed reduction, several methods have been developed such as an optimized scanning pattern and polarization multiplexed dual beam scanning. This research represent novel imaging technique using frequency multiplexed dual beam illumination to measure exactly same position with aimed time interval. Developed system has been verified using a tissue phantom and mouse vessel imaging.

  8. Lorentz invariance and the rotor Doppler shift experiments

    International Nuclear Information System (INIS)

    It is shown that 'Rotor Doppler shift Experiments' provide a way to distinguish Einstein's Special Relativity (SR) from Lorentz's Aether Theory (LAT). Misconceptions in previous papers involving the Doppler shift experiments are examined. The theoretical and experimental data available on rotor Doppler shift experiments are analysed. Two models of SR violating theories are used to predict the output of a recently proposed experiment by Torr and Kolen. The first one corresponds to (strict) LAT and the other to an extended form of LAT. Contrary to the first, the second theory leads to results in agreement with the preliminary experimental data of Torr et al indicating a breakdown both of SR and strict LAT. (Author)

  9. Ballistics and ash plumes discriminated by Doppler radar

    Science.gov (United States)

    Valade, Sébastien; Donnadieu, Franck

    2011-11-01

    Small scale eruptive ash plumes at Arenal volcano (Costa Rica) were recorded using a ground-based Doppler radar (VOLDORAD). The time-velocity distribution of the mass load (i.e., Doppler radargrams) exhibits two contrasted dynamics recorded simultaneously, evidenced by distinctive velocities, life spans, and transit speeds through the radar beam. Synthetic Doppler radargrams computed with a simple ballistic model indicate that the short-lived signal is consistent with the instantaneous projection of ballistics blocks accompanying the ash plume emission. The mass of centimeter- to decimeter-sized ballistics is confidently estimated at 0.5-7 tons, whereas the ash plume mass is loosely constrained at 5.8 × 102 tons, assuming a particle diameter of 2 mm close to the vent. These quantitative estimates of the mass proportion either falling on the slopes of the volcano or ejected into the atmosphere could help in the modeling and monitoring of tephra dispersal.

  10. Optoelectronic measurement in deformation of blast shock with Doppler effect

    Science.gov (United States)

    Shao, Lei; Liu, Hongli; Jiang, Chengzhi

    2009-11-01

    This paper attempts to explore the feasibility of a system based on laser Doppler technique which has been established to realize remote dynamic measurement of high velocity deformation parameters of explosion vessel. It aims at developing a stable and reliable non-contact instrument with high precision for the measuring of explosion on site. Doppler signal's SNR is very low in remote measurement of explosion vessel, a moving solid object with high velocity. To enhance signal intensity, restrain noise and extract weak Doppler signal is the key to realizing remote measurement with high precision. Both optical structure optimizing and digital signal processing used to solve the arduous problem above will be discussed in this paper. The test results prove that the relative error of the instrument is less than 1% in measuring displacement.

  11. Manipulating the spin-dependent splitting by geometric Doppler effect.

    Science.gov (United States)

    Liu, Yachao; Ke, Yougang; Zhou, Junxiao; Luo, Hailu; Wen, Shuangchun

    2015-06-29

    We report the manipulation of spin-dependent splitting by geometric Doppler effect based on dielectric metasurfaces. The extrapolation of rotational Doppler effect from temporal to spatial coordinate gives the phase change when the local optical axes of dielectric metasurfaces are rotating in space. Therefore, the continuous variation of local optical axes in a certain direction will introduce a phase gradient in the same direction at the beam cross section. This is additive to the phase gradient appeared when breaking the rotational symmetry of linearly polarized cylindrical vector beams, which leads to the deflections of different spin components of light, i.e., photonic spin Hall effect. Hence, it is possible to manipulate the spin-dependent splitting by introducing the geometric Doppler effect. Theoretically and experimentally, we show that the magnitude and orientation of the spin-dependent splitting are both tunable when changing the spatial rotation rate of local optical axes and incident polarization. PMID:26191680

  12. Diagnosis of subclavian steal syndrome using color doppler ultrasonography

    International Nuclear Information System (INIS)

    Objective: To evaluate the diagnostic value of color Doppler ultrasonography in subclavian steal syndrome (SSS). Methods: The sonographic appearance and the hemodynamic data of extracranial vertebral, subclavian, innominate arteries in 30 patients with SSS were displayed with color Doppler ultrasonography, and do tourniquet test. Results: The insidious group included 6 cases (20.0%), the partial group included 14 cases (46.6%) and the completed group included 10 (33.3%). The accurately diagnosed cases by ultrasound were 28 (93.3%). The misdiagnosed cases were 2 (6.7%, all in the insidious group). Conclusion: Color Doppler ultrasonography can be prompted to subclavian steal the lesion site, extent and causes, while effectively evaluate the hemodynamic changes in the clinical diagnosis of SSS is the preferred method of imaging examination. (authors)

  13. [Transcranial Doppler and color duplex ultrasound. Familiar and new uses].

    Science.gov (United States)

    Baumgartner, R W; Baumgartner, I B

    1996-04-01

    Transcranial Doppler and color-coded duplex sonography provide reliable information on cross-flow through the circle of Willis, stenoses, occlusions and vasospasm of the major basal cerebral arteries. The CO2 and acetazolamide tests allow quantitative evaluation of the hemodynamic impact of obstructive cerebrovascular disease. Furthermore, transcranial Doppler sonography is used for detection of enhanced intracranial pressure, confirmation of brain death, detection of cerebral microemboli ("high intensity transient signals" = "HITS"), and patent foramen ovale. In the future, cerebral microemboli may become a marker for embolic activity of both occlusive carotid artery and cardiac disease. Transcranial color-coded duplex sonography identifies intracranial hemorrhage, cerebrovascular malformations, and hydrocephalus, but is inferior to neuroradiological techniques. Transpulmonary contrast agents make the examination of patients with inadequate insonation windows feasible, and increase diagnostic confidence in transcranial ultrasonography. Transcranial power-based color-coded duplex sonography ("power Doppler") may further improve transcranial ultrasonography, and visualize flow in smaller vessels. PMID:8685694

  14. Automatic human micro-Doppler signature separation by Hough transform

    Science.gov (United States)

    Zhang, Jun; Jin, Tian; Qiu, Lei; Zhou, Zhimin

    2015-12-01

    The micro-Doppler signature is one of the most prominent information for target classification and identification. As Hough transform (HT) is an efficient tool for detecting weak straight target traces in the image, an HT based algorithm is proposed for micro-Doppler signature separation of multiple persons. Few seconds data is processed at one time to ensure human motion traces approximate to straight lines in the radar slow time-range image. Taking HT to the slow time-range image, each human's motion trace can be recovered through recursively searching the peaks in HT space. Applying time-frequency transform to the range cells around each recovered line, the human micro-Doppler signature can be achieved and separated. Experimental results are given to illustrate the validity of the proposed algorithm.

  15. Lorentz invariance and the rotor Doppler shift experiments

    International Nuclear Information System (INIS)

    It is shown that 'Rotor Doppler shift Experiments' provide a way to distinguish Einstein's Special Relativity (SR) from Lorentz's Aether Theory (LAT). Misconceptions in previous papers involving the Doppler shift experiments are examined. The theoretical and experimental data available on rotor Doppler shift experiments are analysed. Two models of SR violating theories are used to predict the output of a recently proposed experiment by Torr and Kolen. The first one corresponds to (strict) LAT and the other to an extended form of LAT Contrary to the first, the second theory leads to results in agreement with the preliminary experimental data of Torr et al indicating a breakdown both of SR and strict LAT. (Author)

  16. Assessment of endometrial receptivity by Color Doppler and ultrasound imaging

    Directory of Open Access Journals (Sweden)

    Lili? Vekoslav

    2007-01-01

    Full Text Available Introduction: Color Doppler sonography is a new method used to investigate changes during the menstrual cycle in infertile women. The objective of this study was to investigate the correlation of uterine and endomterial-subendomterial blood flow in infertile women using ultrasound and color Doppler sonography. Material and methods: A prospective clinical study included 65 infertile women divided into three groups. Transvaginal ultrasound examination was performed on days XI, XIV and XX. All results were statistically analyzed. We investigated the correlation between cycles, pregnancy outcome and distribution of endomterial-subendomterial blood flow, as well as uterine arterial blood flow. Results and conclusion: Endomterial-subendometerial blood flow distribution pattern assessed by transvaginal color Doppler, as well as good flow in uterine vessels, are necessery for good pregnancy rates. Thin endomterium, undetectable subendomterial blood flow and higher uterine arterial resistance, were associated with low pregnancy rate and poor outcome.

  17. Assessment of right ventricular systolic function by tissue Doppler echocardiography

    DEFF Research Database (Denmark)

    Kjærgaard, Jesper

    2012-01-01

    This thesis summarizes a series of studies performed in order to assess the clinical usefulness of a novel echocardiographic technology that allows non-invasive assessment of regional right ventricular myocardial velocities and deformation: tissue Doppler echocardiography. While the technology is a...... pharmacological pulmonary vasodilatation is established in normal subjects. The diagnostic and prognostic importance of adding tissue Doppler echocardiography to conventional echocardiographic and clinical parameters was evaluated in studies on patients with diseases associated with different modes of impact on...... right ventricular hemodynamics: pulmonary embolism, Arrhythmogenic right ventricular cardiomyopathy and pulmonary regurgitation, the latter in an animal model. The conclusions of the thesis are: Color tissue Doppler echocardiography accurately measures velocities, SR and strain in vitro. No systematic...

  18. Doppler Spectrum from Moving Scatterers in a Random Environment

    DEFF Research Database (Denmark)

    Andersen, Jørgen Bach; Nielsen, Jesper Ødum; Pedersen, Gert Frølund; Bauch, Gerhard; Dietl, Guido

    2009-01-01

    A random non-line-of-sight environment with stationary transmitter and receiver is considered. In such an environment movement of a scatterer will lead to perturbations of the otherwise static channel with a resulting Doppler spectrum. This is quite a general situation in outdoor environments with...... moving traffic or indoor situations with moving people. Here we study the latter situation in detail with experimental results from a large office environment. A general theory of Doppler spectra is developed. The impact of a scatterer depends on the angular distribution of scattered energy, and uniform...... as well as sharply peaked distributions are considered in the theory. The Doppler spectra are in all cases sharply peaked at zero frequency due to forward scattering, but the actually measured distribution depends on the degree and type of activity in the environment, as well as the spectrum...

  19. Micro-range micro-doppler for dismount classification

    Science.gov (United States)

    Tahmoush, Dave

    2013-05-01

    This paper presents a processing technique that can be used to detect and classify pedestrians group based on the micro- Doppler signature gathered with a millimeter wave radar. The evaluation of the number of pedestrians moving in a group can be a difficult task using a traditional micro-Doppler spectrogram because of a tendency for people to partially synchronize their steps when walking together. The new approach, based on multi-range variation as well as the micro-Doppler variations, provides promising results. The range-spectrogram processing technique was developed and tested using a database composed of hundreds of pedestrian and vehicle signatures gathered in an urban test site over a two year period in a variety of weather conditions. We associate image detections with radar detections through motion extracted from both radar and imagery. We also explain how radar and video together can produce an inexpensive alternative to 3-D imaging.

  20. Holographic laser Doppler imaging of microvascular blood flow

    CERN Document Server

    Magnain, C; Boucneau, T; Simonutti, M; Ferezou, I; Rancillac, A; Vitalis, T; Sahel, J A; Paques, M; Atlan, M

    2014-01-01

    We report on local superficial blood flow monitoring in biological tissue from laser Doppler holographic imaging. In time averaging recording conditions, holography acts as a narrowband bandpass filter, which, combined with a frequency shifted reference beam, permits frequency selective imaging in the radiofrequency range. These Doppler images are acquired with an off axis Mach Zehnder interferometer. Microvascular hemodynamic components mapping is performed in the cerebral cortex of the mouse and the eye fundus of the rat with near-infrared laser light without any exogenous marker. These measures are made from a basic inverse method analysis of local first order optical fluctuation spectra at low radiofrequencies, from 0 Hz to 100 kHz. Local quadratic velocity is derived from Doppler broadenings induced by fluid flows, with elementary diffusing wave spectroscopy formalism in backscattering configuration. We demonstrate quadratic mean velocity assessment in the 0.1 to 10 millimeters per second range in vitro ...

  1. The Doppler paradigm and the APEX-EPOS-ORANGE quandary

    International Nuclear Information System (INIS)

    The experimental detection of the sharp lines of the (e+e-) Puzzle is viewed as a struggle against Doppler broadening. Gedanken experiments which are realistic in zeroth order of detail are analyzed to show that the ORANGE and EPOS/I geometries select narrower slices of a Doppler broadened line than spherically inclusive (APEX and EPOS/II -like) apparati. Roughly speaking, the latter require event-by-event Doppler reconstruction simply to regain an even footing with the former. This suggests that APEX' or EPOS/II's coincident pair distributions must be statistically superior to those of EPOS/I or ORANGE in order to support a comparable inference about sharp structure. Under such circumstances, independent alternative data is invaluable. Therefore, a corroboration of Sakai's 330.1 keV (+ or e- bombardments of U and Th targets could prove crucial

  2. Doppler term in the galaxy two-point correlation function: wide-angle, velocity, Doppler lensing and cosmic acceleration effects

    CERN Document Server

    Raccanelli, Alvise; Jeong, Donghui; Neyrinck, Mark C; Szalay, Alexander S

    2016-01-01

    We study the parity-odd part (that we shall call Doppler term) of the linear galaxy two-point correlation function that arises from wide-angle, velocity, Doppler lensing and cosmic acceleration effects. As it is important at low redshift and at large angular separations, the Doppler term is usually neglected in the current generation of galaxy surveys. For future wide-angle galaxy surveys such as Euclid, SPHEREx and SKA, however, we show that the Doppler term must be included. The effect of these terms is dominated by the magnification due to relativistic aberration effects and the slope of the galaxy redshift distribution and it generally mimics the effect of the local type primordial non-Gaussianity with the effective nonlinearity parameter $f_{\\rm NL}^{\\rm eff}$ of a few, we show that this would affect forecasts on measurements of $f_{\\rm NL}$ at low-redshift. Our results show that a survey at low redshift with large number density over a wide area of the sky could detect the Doppler term with a signal-to-...

  3. Can the ductus venosus doppler predict the hemoglobinopathies?

    Science.gov (United States)

    Karateke, Atilla; Silfeler, Dilek Benk; Güngören, Arif; Kurt, Raziye Keskin; Okyay, Ay?e Güler; Dokuyucu, Recep; Ulutas, Turker; Un, Burak; Paksoy, Hacer; Hakverdi, Ali Ulvi

    2015-01-01

    Objective: The aim of our study was to investigate the ductus venosus doppler between 11-13+6 (week-day) in pregnant women with hemoglobinopaties and its relation with fetal outcomes. Material and methods: A total of 100 pregnant women with hemoglobinopathies and 100 healthy pregnant women were included in our study. Ultrasonography (USG) was performed to all pregnant women and the ductus venosus doppler (DVD) flows were evaluated. The results were statistically analyzed. Results: The mean hemoglobin level was significantly lower in hemoglobinopathy group (9.7 ± 0.7) than control group (10.67 ± 0.82) (P<0.001). There was a significant relationship between Vmax, Vmin, S/D and reverse ‘a’ wave in fetuses with hemoglobinopathies. Vmax, Vmin and S/D parameters were higher in the group of hemoglobinopathies (respectively mean value, 31.3 ± 1.66, 8.90 ± 0.81, 2.97 ± 0.49). Reverse ‘a’ wave was detected especially in all fetuses with sickle cell anemia. There was no significantly relationship between the groups in terms of PI, RI and HR. In a logistic regression analyses, fetal hemoglobinopathy was independently associated with Vmin (? = 1.07, P = 0.001), S/D (? = 2.61, P = 0.001) and reverse ‘a’ wave (? = 2.46, P = 0.004). Conclusion: Pregnant women with hemoglobinopathies had changed ductus venosus doppler values in compared to normal pregnant women. Maternal anemia may cause this doppler changes. Furthermore all fetuses with sickle cell anemia (n = 5) had abnormal ductus venosus doppler findings. Further studies are needed to investigate the relationship between abnormal ductus venosus doppler findings and fetuses diagnosed with sickle cell anemia. PMID:26064361

  4. UltraFast Doppler ultrasonography for hepatic vessels of liver recipients: preliminary experiences

    Energy Technology Data Exchange (ETDEWEB)

    Hur, Bo Yun; Lee, Jae Young; Chu, A Jung; Kim, Se Hyung; Han, Joon Koo; Choi, Byung Ihn [Seoul National University Hospital, Seoul (Korea, Republic of)

    2015-01-15

    The purpose of this study was to investigate the value of UltraFast Doppler ultrasonography (US) for evaluating hepatic vessels in liver recipients. Thirty-nine liver Doppler US sessions were conducted in 20 liver recipients. Each session consisted of UltraFast and conventional liver Doppler US in a random order. We compared the velocities and phasicities of the hepatic vessels, duration of each Doppler study, occurrence of technical failures, and differences in clinical decisions. The velocities and resistive index values of hepatic vessels showed a strong positive correlation between the two Doppler studies (mean R=0.806; range, 0.710 to 0.924). The phasicities of the hepatic vessels were the same in both Doppler US exams. With respect to the duration of the Doppler US exam, there was no significant difference between the UltraFast (251±99 seconds) and conventional (231±117 seconds) Doppler studies (P=0.306). In five poor breath-holders, in whom the duration of conventional Doppler US was longer, UltraFast Doppler US (272±157 seconds) required a shorter time than conventional Doppler US (381±133 seconds; P=0.005). There was no difference between the two techniques with respect to technical failures and clinical decisions. UltraFast Doppler US is clinically equivalent to conventional Doppler US with advantages for poor breath-holders during the post-liver transplantation work-up.

  5. UltraFast Doppler ultrasonography for hepatic vessels of liver recipients: preliminary experiences

    International Nuclear Information System (INIS)

    The purpose of this study was to investigate the value of UltraFast Doppler ultrasonography (US) for evaluating hepatic vessels in liver recipients. Thirty-nine liver Doppler US sessions were conducted in 20 liver recipients. Each session consisted of UltraFast and conventional liver Doppler US in a random order. We compared the velocities and phasicities of the hepatic vessels, duration of each Doppler study, occurrence of technical failures, and differences in clinical decisions. The velocities and resistive index values of hepatic vessels showed a strong positive correlation between the two Doppler studies (mean R=0.806; range, 0.710 to 0.924). The phasicities of the hepatic vessels were the same in both Doppler US exams. With respect to the duration of the Doppler US exam, there was no significant difference between the UltraFast (251±99 seconds) and conventional (231±117 seconds) Doppler studies (P=0.306). In five poor breath-holders, in whom the duration of conventional Doppler US was longer, UltraFast Doppler US (272±157 seconds) required a shorter time than conventional Doppler US (381±133 seconds; P=0.005). There was no difference between the two techniques with respect to technical failures and clinical decisions. UltraFast Doppler US is clinically equivalent to conventional Doppler US with advantages for poor breath-holders during the post-liver transplantation work-up.

  6. Large Doppler Compensation for Mobile OFDM Based Underwater Acoustic Communication

    Directory of Open Access Journals (Sweden)

    Zhengrong Pan

    2013-01-01

    Full Text Available In this study, large Doppler compensation for Orthogonal Frequency Division Multiplexing (OFDM suitable for mobile underwater acoustic communication is proposed. The scheme is applicable to underwater acoustic communication between rapidly moving platforms. Considering the structural characteristics of OFDM symbols, re-sampling and time-frequency differential code mapping are used to realize the broadband and narrowband Doppler compensation. The experimental results prove the feasibility of the proposed scheme. In addition, the error performance of this scheme in different Signal-to-Noise Ratio (SNR and different relative speed is given.

  7. Fano-Doppler laser cooling of hybrid nanostructures.

    Science.gov (United States)

    Ridolfo, Alessandro; Saija, Rosalba; Savasta, Salvatore; Jones, Philip H; Iatì, Maria Antonia; Maragò, Onofrio M

    2011-09-27

    Laser cooling the center-of-mass motion of systems that exhibit Fano resonances is discussed. We find that cooling occurs for red or blue detuning of the laser frequency from resonance depending on the Fano factor associated with the resonance. The combination of the Doppler effect with the radiation cross-section quenching typical of quantum interference yields temperatures below the conventional Doppler limit. This scheme opens perspectives for controlling the motion of mesoscopic systems such as hybrid nanostructures at the quantum regime and the exploration of motional nonclassical states at the nanoscale. PMID:21806014

  8. Numerical stud of glare spot phase Doppler anemometry

    OpenAIRE

    Hespel, Camille; Ren, Kuan Fang; Gréhan, Gérard; Onofri, Fabrice

    2008-01-01

    The phase Doppler anemometry has (PDA) been developed to measure simultaneously the velocity and the size of droplets. When the concentration of particles is high, tightly focused beams must be used, as in the dual burst PDA. The latter permits an access to the refractive index of the particle, but the effect of wave front curvature of the incident beams becomes evident. In this paper, we introduce a glare spot phase Doppler anemometry which uses two large beams. The images of the particle fo...

  9. Feasibility assessment of Doppler radar long-term physiological measurements.

    Science.gov (United States)

    Massagram, Wansuree; Lubecke, Victor M; Boric-Lubecke, Olga

    2011-01-01

    In this paper we examine the feasibility of applying doppler radar technique for a long-term health monitoring. Doppler radar was used to detect and eliminate periods of significant motion. This technique was verified using a human study on 17 subjects, and it was determined that for 15 out of 17 subjects there was no significant motion for over 85% of the measurement interval in supine positions. Majority of subjects exhibited significantly less motion in supine position, which is promising for sleep monitoring, and monitoring of hospitalized patients. PMID:22254615

  10. Doppler shifts in the coma of Comet P/Halley

    International Nuclear Information System (INIS)

    The relative radial velocities across 70-100 arcsecs of the coma of Comet P/Halley were measured on four days in 1985-1986 on coude CCD spectrograms in order to search for detectable Doppler shifts. The measurements show a trend of positive velocity with respect to projected distance from the nucleus. The shifts are most clearly observed at r = 1.1 AU, where the relative velocity at 10000 km amounted to 3-4 km/s. The Doppler shifts represent an integration through the whole coma. It is suggested that a proper model of the comet is needed to convert the shifts into true outflow velocities. 14 refs

  11. Multigroup Free-atom Doppler-broadening Approximation. Theory

    Energy Technology Data Exchange (ETDEWEB)

    Gray, Mark Girard [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-11-06

    Multigroup cross sections at a one target temperature can be Doppler-broadened to multigroup cross sections at a higher target temperature by matrix multiplication if the group structure suf- ficiently resolves the original temperature continuous energy cross section. Matrix elements are the higher temperature group weighted averages of the integral over the lower temperature group boundaries of the free-atom Doppler-broadening kernel. The results match theory for constant and 1/v multigroup cross sections at 618 lanl group structure resolution.

  12. Doppler-broadening of positron annihilation in a biological environment

    International Nuclear Information System (INIS)

    The aim of this study was to investigate the Doppler effect of the 511 keV ? peak from positron annihilation in biological matter: The broadening of the annihilation peak is due to positron annihilation with electrons that have high momentum. In aqueous solutions annihilation depends on the temperature and it is linked positronium formation. Measurements in vivo, on human brain, were taken during the diagnosis of positron emission tomography (PET) on healthy patients by injecting them with the beta emitter of short lifetime 18F. The Doppler-broadening in biological tissues rich in water content decreased significantly compared to biological solutions and water

  13. Determination of Doppler Effect on nuclear resonances of uranium-238

    International Nuclear Information System (INIS)

    This paper deals with theoretical and experimental study of Doppler effect on 238U resonances. The chosen experimental method was based on measuring gamma activities of irradiated UO2 samples with natural uranium since this activity depends on the total absorption in 238U dependent on the temperature of the sample. Special electrical heater was used for heating the samples irradiated in the core of RB reactor. Due to significant perturbation of neutron flux caused by the presence of the heater it was necessary to develop a model for calculation of Doppler effect on 238U in the used sample. Scintillation NaI(Tl) detector was used for gamma activity measurements

  14. Aerial ultrasonic micro Doppler sonar detection range in outdoor environments.

    Science.gov (United States)

    Bradley, Marshall; Sabatier, James M

    2012-03-01

    Current research demonstrates that micro Doppler sonar has the capability to uniquely identify the presence of a moving human, making it an attractive component in surveillance systems for border security applications. Primary environmental factors that limit sonar performance are two-way spreading losses, ultrasonic absorption, and backscattered energy from the ground that appears at zero Doppler shift in the sonar signal processor. Spectral leakage from the backscatter component has a significant effect on sonar performance for slow moving targets. Sonar performance is shown to rapidly decay as the sensor is moved closer to the ground due to increasing surface backscatter levels. PMID:22423809

  15. Spectral fine structure effects on material and doppler reactivity worth

    International Nuclear Information System (INIS)

    New formulations concerning the fine structure effects on the reactivity worth of resonances are developed and conclusions are derived following the extension to more general types of perturbations which include: the removal of resonance material at finite temperatures and the temperature variation of part of the resonance material. It is concluded that the flux method can overpredict the reactivity worth of resonance materials more than anticipated. Calculations on the Doppler worth were carried out; the results can be useful for asessing the contribution of the fine structure effects to the large discrepancy that exists between the calculated and measured small sample Doppler worths. (B.G.)

  16. Prenatal color Doppler ultrasonographic diagnosis of fetal tetralogy of Fallot

    International Nuclear Information System (INIS)

    Objective: To investigate the sonographic findings of tetralogy of Fallot in fetuses. Methods: The data of color Doppler ultrasonography and follow-up results of 5 fetal tetralogy of Fallot were analyzed retrospectively, and their abnormal ultrasound imaging characteristic were summarized. Results: Two cases were proved tetralogy of Fallot by autopsy, and three cases were confirmed to be tetralogy of Fallot by echocardiography after birth. The image features were the main aorta situated above the ventricular septal defect, pulmonary stenosis, no obvious thickening of the right wall. Conclusion: Fetal tetralogy of Fallot have characteristic ultrasound images, prenatal color Doppler ultrasonographic can diagnoses fetal tetralogy of Fallot correctly and has important clinical value. (authors)

  17. The Dependence of the Resonance Integral on the Doppler Effect

    International Nuclear Information System (INIS)

    The Doppler sensitive contributions to the resonance integral for metal and oxide cylinders have been calculated using tables compiled by Adler, Hinman and Nordheim. The temperatures 20, 200, 350, 500 and 650 deg C have been investigated for the pure metal and 20, 300, 600, 900 and 1200 deg C for the oxide. Contributions from the separate resonances in the resolved region and for certain energies in the unresolved region are accounted for in detail. Integration over adequate statistical distributions has been carried out for the resonance parameters in the unresolved region. The increase in the resonance integral at elevated temperatures due to the Doppler effect is given separately in tables and diagrams

  18. Void effects on BWR Doppler and void reactivity feedback

    International Nuclear Information System (INIS)

    The significance of steam voids and control rods on the Doppler feedback in a gadolinia shimmed BWR is demonstrated. The importance of bypass voids when determining void feedback is also shown. Calculations were done using a point model, i.e., feedback was expressed in terms of reactivity coefficients which were determined for individual four-bundle configurations and then appropriately combined to yield reactor results. For overpower transients the inclusion of the void effect of control rods is to reduce Doppler feedback. For overpressurization transients the inclusion of the effect of bypass void wil increase the reactivity due to void collapse. (author)

  19. Doppler controlled dynamics of a mirror attached to a spring

    OpenAIRE

    Karrai, Khaled; Favero, Ivan; Metzger, Constanze

    2007-01-01

    A laser beam directed at a mirror attached onto a flexible mount extracts thermal energy from its mechanical Brownian motion by Doppler effect. For a normal mirror the efficiency of this Doppler cooling is very weak and masked by laser shot-noise. We find that it can become very efficient using a Bragg mirror at the long wavelength edge of its band stop. The opposite effect of cooling opens new routes for optical pumping of mechanical systems: a laser pointing at a Bragg mir...

  20. Investigation of ionospheric effects of solar flares by Doppler method

    International Nuclear Information System (INIS)

    Ionospheric effects during solar flares, recorded by the Doppler method on the Fort Collins (USA) - Havana (Cuba) route are considered. According to the data of sudden frequency deviations (SFD) approximated profiles of electron concentration in the F1 region are calculated. For the flare on the 15th February,1978 estimation of the integral flux of solar irradiation in the range of wave lengths from 100 to 1030 A equals to 0.39 erg/cm2xs. It is pointed out that Doppler measurements for flares of different types are very important for creation of reliable models of ionosphere disturbance

  1. Observational limitations of the Doppler theory of quasars

    International Nuclear Information System (INIS)

    This paper is mainly concerned with the hypothesis that the redshift of a quasar is entirely due to the Doppler effect arising from its high speed of ejection in a relatively nearby center of explosion. We examine the viability of this hypothesis in the light of the available data on the aligned triplets of quasars discovered by Arp and Hazard and by Saslaw. Before applying the Doppler hypothesis we consider in some detail, using computer simulations, whether such well aligned triplet configurations could have arisen by chance projection effects under the cosmological hypothesis. Even allowing for various uncertainties and selection effects, we find such a development rather unlikely

  2. Grayscale and color Doppler features of testicular lymphoma.

    Science.gov (United States)

    Bertolotto, Michele; Derchi, Lorenzo E; Secil, Mustafa; Dogra, Vikram; Sidhu, Paul S; Clements, Richard; Freeman, Simon; Grenier, Nicolas; Mannelli, Lorenzo; Ramchandani, Parvati; Cicero, Calogero; Abete, Luca; Bussani, Rossana; Rocher, Laurence; Spencer, John; Tsili, Athina; Valentino, Massimo; Pavlica, Pietro

    2015-06-01

    Pooled data from 16 radiology centers were retrospectively analyzed to seek patients with pathologically proven testicular lymphoma and grayscale and color Doppler images available for review. Forty-three cases were found: 36 (84%) primary and 7 (16%) secondary testicular lymphoma. With unilateral primary lymphoma, involvement was unifocal (n = 10), multifocal (n = 11), or diffuse (n = 11). Synchronous bilateral involvement occurred in 6 patients. Color Doppler sonography showed normal testicular vessels within the tumor in 31 of 43 lymphomas (72%). Testicular lymphoma infiltrates through the tubules, preserving the normal vascular architecture of the testis. Depiction of normal testicular vessels crossing the lesion is a useful adjunctive diagnostic criterion. PMID:26014335

  3. New measurement of the relativistic Doppler shift in neon

    International Nuclear Information System (INIS)

    The Doppler free two photon transition from the metastable 1S5 to 4S1'double-prime in neon was measured for both a fast beam (?120 keV) and a slow thermal beam. The transition frequencies for each beam were measured independently relative to a hyperfine component of a nearby I2 reference line. The absolute frequency shift between the two beams was obtained. This measurement of the relativistic Doppler shift verifies the time dilation effect to an accuracy of 2.3 ppm which represents a more than 10 fold improvement over previous measurements

  4. Optical Doppler tomography based on a field programmable gate array

    DEFF Research Database (Denmark)

    Larsen, Henning Engelbrecht; Nilsson, Ronnie Thorup; Thrane, Lars; Pedersen, Finn; Jørgensen, Thomas Martini; Andersen, Peter E.

    2008-01-01

    We report the design of and results obtained by using a field programmable gate array (FPGA) to digitally process optical Doppler tomography signals. The processor fits into the analog signal path in an existing optical coherence tomography setup. We demonstrate both Doppler frequency and envelope...... extraction using the Hilbert transform, all in a single FPGA. An FPGA implementation has certain advantages over general purpose digital signal processor (DSP) due to the fact that the processing elements operate in parallel as opposed to the DSP. which is primarily a sequential processor....

  5. Doppler shifted H Ly alpha emission from Jupiter's aurora

    Science.gov (United States)

    Clarke, John T.; Trauger, John; Waite, J. Hunter, Jr.

    1989-01-01

    High-spectral-resolution IUE observations of the aurora on Jupiter were obtained in order to search for Doppler shifted H-Ly-alpha emission produced through charge exchange by fast precipitating protons. Although no emission has been observed corresponding to proton energies greater than 200 eV, a large fraction of the H-Ly-alpha emission has appeared Doppler shifted, mainly toward the blue, by about 50 km/s. These results show that the acceleration of ionospheric plasma in an H2 atmosphere can lead to bright Ly-alpha emission, setting constraints on the production of the outer planet airglow emissions.

  6. Transcranial Doppler for detection of cerebral ischaemia during carotid endarterectomy

    DEFF Research Database (Denmark)

    Jørgensen, L G; Schroeder, T V

    1992-01-01

    We evaluated transcranial Doppler sonography (TCD) for the detection of cerebral ischaemia during carotid endarterectomy in 30 male and 14 female patients with ipsilateral focal cerebro-vascular symptoms. Surgery was performed during halothane-nitrous oxide anaesthesia with moderate hypocapnia....... Eight patients had a temporary shunt owing to contralateral occlusion or a stump pressure below 40 mmHg, and/or EEG flattening. Transcranial Doppler sonography was followed intra-operatively together with electro-encephalography (EEG), internal carotid artery (ICA) pressures and cerebral blood flow (CBF...

  7. Imaging doppler lidar for wind turbine wake profiling

    Energy Technology Data Exchange (ETDEWEB)

    Bossert, David J.

    2015-11-19

    An imaging Doppler lidar (IDL) enables the measurement of the velocity distribution of a large volume, in parallel, and at high spatial resolution in the wake of a wind turbine. Because the IDL is non-scanning, it can be orders of magnitude faster than conventional coherent lidar approaches. Scattering can be obtained from naturally occurring aerosol particles. Furthermore, the wind velocity can be measured directly from Doppler shifts of the laser light, so the measurement can be accomplished at large standoff and at wide fields-of-view.

  8. Ultrasonography and color Doppler in juvenile idiopathic arthritis

    DEFF Research Database (Denmark)

    Laurell, Louise; Court-Payen, Michel; Nielsen, Susan; Zak, Marek; Boesen, Mikael; Fasth, Anders

    2011-01-01

    Background The ankle region is frequently involved in juvenile idiopathic arthritis (JIA) but difficult to examine clinically due to its anatomical complexity. The aim of the study was to evaluate the role of ultrasonography (US) of the ankle and midfoot (ankle region) in JIA. Doppler-US detected...... hypertrophy, effusion) and by color Doppler (synovial hyperemia) before and 4 weeks after US-guided steroid injection. Results US detected 121 compartments with active disease (joints, tendon sheaths and 1 ganglion cyst). Multiple compartments were involved in 80% of the ankle regions. The talo-crural joint...

  9. Validation of the Leopard code for Doppler reactivity coefficient calculation

    International Nuclear Information System (INIS)

    The Doppler coefficient of reactivity is a crucial parameter in the evaluation of several transients for light water reactors (PWR and BWR). It is relatively small in magnitude and cannot be measured directly. This paper includes several results for Doppler coefficient, using LEOPARD code, applied to PWR pin cells of five different enrichments, from 0.711 to 3.9 wt%. The LEOPARD calculations were run for two cross section libraries, ENDF/B-II and ENDF/B IV. The results were compared with benchmark calculated by a Monte Carlo code with a million neutron histories, with good agreement. (author)

  10. Analysis of multiple scattering effects in optical Doppler tomography

    DEFF Research Database (Denmark)

    Yura, H.T.; Thrane, L.; Andersen, Peter E.

    Optical Doppler tomography (ODT) combines Doppler velocimetry and optical coherence tomography (OCT) to obtain high-resolution cross-sectional imaging of particle flow velocity in scattering media such as the human retina and skin. Here, we present the results of a theoretical analysis of ODT where......-resolved retinal flow profiles where the influence of multiple scattering was observed [Yazdanfar et al., Opt. Lett. 25, 1448 (2000)]. To the best of our knowledge, no analytical model exists that are able to explain these observations....

  11. Using fraction images derived from modis data for coffee crop mapping / Utilização de imagens-fração derivadas do sensor modis para o mapeamento de lavouras de café

    Scientific Electronic Library Online (English)

    Rafael C., Bispo; Rubens A. C., Lamparelli; Jansle V., Rocha.

    2014-02-01

    Full Text Available A produção de café esteve intimamente ligada ao desenvolvimento econômico do Brasil e ainda hoje o café é um importante produto da agricultura nacional. O Estado de Minas Gerais responde atualmente por 52% de toda a área de café do Brasil. Dados de sensoriamento remoto podem fornecer informações par [...] a o monitoramento e o mapeamento de café de maneira mais rápida e menos onerosa do que os métodos convencionais. Nesse contexto, o objetivo deste trabalho foi avaliar a eficácia do mapeamento de áreas de café do município de Monte Santo de Minas-MG, a partir de imagens-fração derivadas do sensor MODIS, nas estações de estiagem e de chuva. Através do Modelo Linear de Mistura Espectral, foram derivadas imagens-fração de solo, café e água/sombra. Estas imagens-fração serviram como dados de entrada para a classificação automática supervisionada com o método SVM - Support Vector Machine. Os melhores resultados de Exatidão Global e Índice Kappa foram obtidos na classificação do período seco, sendo 67% e 0,41, respectivamente. Abstract in english Coffee production was closely linked to the economic development of Brazil and, even today, coffee is an important product of the national agriculture. The State of Minas Gerais currently accounts for 52% of the whole coffee area in Brazil. Remote sensing data can provide information for monitoring [...] and mapping of coffee crops, faster and cheaper than conventional methods. In this context, the objective of this study was to assess the effectiveness of coffee crop mapping in Monte Santo de Minas municipality, Minas Gerais State, Brazil, from fraction images derived from MODIS data, in both dry and rainy seasons. The Spectral Linear Mixing Model was used to derive fraction images of soil, coffee, and water/shade. These fraction images served as input data for the supervised automatic classification using the SVM - Support Vector Machine approach. The best results concerning Overall Accuracy and Kappa Index were obtained in the classification of the dry season, with 67% and 0.41, respectively.

  12. Utilidad del doppler transcraneal en la hemorragia subaracnoidea: Revisión / Usefulness of transcranial doppler in subarachnoid hemorrhage: Review

    Scientific Electronic Library Online (English)

    Claudio E, Scherle-Matamoros; Jesús, Pérez-Nellar.

    2011-03-01

    Full Text Available Esta revisión resume la utilidad del Doppler transcraneal (DTC) para la evaluación de la hemorragia subaracnoidea en instalaciones de una unidad de tratamiento de accidente vascular. Se presentan los principios hemodinámicos básicos. Se discute la eficiencia, las ventajas y las limitaciones del DTC [...] y los métodos de interpretación. Abstract in english This review summarizes the usefulness of transcranial Doppler (TCD) for the assessment of subarachnoid hemorrhage in the setting of a stroke unit. The basic hemodynamic principles are presented. We discuss the accuracy, the advantages and limitations of the TCD and the interpretation methods. [...

  13. Radar micro-Doppler of wind turbines: Simulation and analysis using rotating linear wire structures:

    OpenAIRE

    Krasnov, O. A.; Yarovoy, A.

    2015-01-01

    A simple electromagnetic model of wind-turbine's main structural elements as the linear wired structures is developed to simulate the temporal patterns of observed radar return Doppler spectra (micro-Doppler). Using the model, the micro-Doppler for different combinations of the turbines rotation frequency, radar pulse repetition frequency, and duration of the Doppler measurement interval are analyzed. The model is validated using the PARSAX radar experimental data. The model ability to reprod...

  14. Realizing Tunable Inverse and Normal Doppler Shifts in Reconfigurable RF Metamaterials

    OpenAIRE

    Ran, Jia; Zhang, Yewen; Chen, xiaodong; Fang, Kai; Zhao, Junfei; Yong SUN; Chen, Hong

    2015-01-01

    The Doppler effect has well-established applications in astronomy, medicine, radar and metrology. Recently, a number of experimental demonstrations of the inverse Doppler effect have begun to appear. However, the inverse Doppler effect has never been observed on an electronically reconfigurable system with an external electromagnetic wave source at radio frequencies (RF) in experiment. Here we demonstrate an experimental observation of the inverse Doppler shift on an electronically reconfigur...

  15. A New Underwater Acoustic Navigation Method Based on the Doppler Principle

    OpenAIRE

    Jinsong Tang; Kun Fang; Sen Zhang

    2013-01-01

    In this paper, a new underwater acoustic navigation method is proposed, which is named from Doppler Acoustic Omnirange Beacon (DAOB). It is borrowed from the idea of Doppler VHF Omnirange (DVOR) and based on the Doppler principle. The cause of Doppler effect in the received signal is the motion or position change of one or two sources. The effect of multipath is analyzed, and an improved signal form is presented to solve the rigorous multipath environment underwater. Some simulation is presen...

  16. Design and Implementation of High Frequency Ultrasound Pulsed-Wave Doppler Using FPGA

    OpenAIRE

    Hu, Chang-Hong; ZHOU, QIFA; Shung, K. Kirk.

    2008-01-01

    The development of a field-programmable gate array (FPGA)-based pulsed-wave Doppler processing approach in pure digital domain is reported in this paper. After the ultrasound signals are digitized, directional Doppler frequency shifts are obtained with a digital-down converter followed by a low-pass filter. A Doppler spectrum is then calculated using the complex fast Fourier transform core inside the FPGA. In this approach, a pulsed-wave Doppler implementation core with reconfigurable and rea...

  17. Check list Doppler and duplex sonography. 4. rev. ed.

    International Nuclear Information System (INIS)

    Check list Doppler and duplex sonography includes 4 parts: (1) Basic information: technical fundamentals, equipment premises, hemodynamics. (2) Flow schemata and pitfalls. (3) Special vascular regions: arteries in the upper and lower extremities, veins in the upper and lower extremities, abdominal arteries, abdominal veins, ex-cranial brain sustaining arteries, intra-cranial brain sustaining arteries. (4) Attachment: diagnostic criteria and case studies.

  18. Enhanced color Doppler sonography of eye and orbit tumors

    International Nuclear Information System (INIS)

    They investigated the diagnostic efficacy of the administration of a sonography (US) contrast agent to study eye and orbit tumors at different stages. They administered Levovist (Schering), an air micro bubble stabilized by fatty acid, which is specific for angiographic indications. Baseline color Doppler US was performed on 24 selected patients and tumor vascularization patterns were classified into 3 classes. Color Doppler signal enhancement was assessed after contrast agent administration and the signal-to-noise ratio (SNR) was improved in 70 % of cases, which helped identify vascular patterns and improved flow metric accuracy. The Doppler effect was also improved and vascular signal was always enhanced. The SNR was improved also by the postcontrast detection of small vessels missed on baseline scans. Doppler signal enhancement was proportional to precontrast vascularization and depended on tumor size, with poor results in lesions < 5 mm. In contrast, vascular signal spots with increased postcontrast echogenicity sometimes caused excessive noise affecting the results. No correlation was found between signal enhancement and lesion histotype or between signal and lesion site. Treated lesions exhibited poorer contrast agent enhancement. The examination technique must be accurate and the various parameters set optimally, especially the velocity scale, gain and filtration; the unit must feature adequate recording capabilities. To conclude, they believe that the routine use of i.v. US contrast agents will play a major role in improving diagnostic imaging in oculistics also thanks to the lack of untoward reactions and to the ease of contrast agent preparation

  19. Multi-sensor Doppler radar for machine tool collision detection

    Science.gov (United States)

    Wächter, T. J.; Siart, U.; Eibert, T. F.; Bonerz, S.

    2014-11-01

    Machine damage due to tool collisions is a widespread issue in milling production. These collisions are typically caused by human errors. A solution for this problem is proposed based on a low-complexity 24 GHz continuous wave (CW) radar system. The developed monitoring system is able to detect moving objects by evaluating the Doppler shift. It combines incoherent information from several spatially distributed Doppler sensors and estimates the distance between an object and the sensors. The specially designed compact prototype contains up to five radar sensor modules and amplifiers yet fits into the limited available space. In this first approach we concentrate on the Doppler-based positioning of a single moving target. The recorded signals are preprocessed in order to remove noise and interference from the machinery hall. We conducted and processed system measurements with this prototype. The Doppler frequency estimation and the object position obtained after signal conditioning and processing with the developed algorithm were in good agreement with the reference coordinates provided by the machine's control unit.

  20. Doppler radar velocity measurements for wound ballistics experiments.

    Science.gov (United States)

    Knudsen, P J; Svender, J

    1994-01-01

    Bullet velocity is a basic parameter in wound ballistics studies. It is usually measured electronically by means of a variety of solid or photoelectric barriers connected to equipment measuring the time elapsing between impulses, enabling the velocity to be calculated. With the advent of Doppler radar velocity measurement of large calibre artillery shells, the use of this equipment for wound ballistics experiments was investigated. Anaesthetized pigs were shot at a range of 9-10 metres and the velocities measured by Doppler radar and photocells were compared. A very good correspondence between the measured entry and exit velocities in low and medium velocity bullets was found, i.e. an average deviation of less than 1% (range 0-2%) between the two types of equipment. In high velocity bullets measurement of entry velocities was just as good, but in both methods measurement of the exit velocity was complicated by the cluttering of signals by fragments of tissue released from the exit wound and the deflection of the bullet, Doppler radar offers important benefits - simple set up, minimal risk of damage of equipment by stray bullets and very good accuracy - and may replace photocells and similar equipment in studies involving low and medium velocity bullets. Measurement of the exit velocity of high velocity bullets is unsatisfactory in both methods, and it is necessary to improve the Doppler radar method in order to measure that as well. PMID:7999640

  1. Generalized Doppler effect in spaces with a transport along paths

    CERN Document Server

    Iliev, Bozhidar Z

    1995-01-01

    An analog of the classical Doppler effect is investigated in spaces (manifolds) whose tangent bundle is endowed with a transport along paths, which, in particular, can be parallel one. The obtained results are valid irrespectively to the particles mass, i.e. they hold for massless particles (e.g. photons) as well as for massive ones.

  2. Anomaly Detection In Additively Manufactured Parts Using Laser Doppler Vibrometery

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, Carlos A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-09-29

    Additively manufactured parts are susceptible to non-uniform structure caused by the unique manufacturing process. This can lead to structural weakness or catastrophic failure. Using laser Doppler vibrometry and frequency response analysis, non-contact detection of anomalies in additively manufactured parts may be possible. Preliminary tests show promise for small scale detection, but more future work is necessary.

  3. Noise Studies of Externally Dispersed Interferometry for Doppler Velocimetry

    Energy Technology Data Exchange (ETDEWEB)

    Erskine, D J; Edelstein, J; Lloyd, J; Muirhead, P

    2006-05-04

    Externally Dispersed Interferometry (EDI) is the series combination of a fixed-delay field-widened Michelson interferometer with a dispersive spectrograph. This combination boosts the spectrograph performance for both Doppler velocimetry and high resolution spectroscopy. The interferometer creates a periodic comb that multiplies against the input spectrum to create moire fringes, which are recorded in combination with the regular spectrum. Both regular and high-frequency spectral components can be recovered from the data--the moire component carries additional information that increases the signal to noise for velocimetry and spectroscopy. Here we present simulations and theoretical studies of the photon limited Doppler velocity noise in an EDI. We used a model spectrum of a 1600K temperature star. For several rotational blurring velocities 0, 7.5, 15 and 25 km/s we calculated the dimensionless Doppler quality index (Q) versus wavenumber v. This is the normalized RMS of the derivative of the spectrum and is proportional to the photon-limited Doppler signal to noise ratio.

  4. Wing tip vortex measurements with laser Doppler systems

    Science.gov (United States)

    Fuller, C. E., III

    1973-01-01

    The vortex velocity field produced by a rectangular wing in a subsonic wind tunnel was measured using two laser Doppler velocimeter systems. One system made three dimensional mean velocity measurements and the other made one dimensional turbulence measurements. The systems and test procedures are described and comparisons of the measurements are made. The data defined a strong spiral motion in the vortex formation process.

  5. Some applications of the Doppler-effect in nuclear spectroscopy

    International Nuclear Information System (INIS)

    The basic physical ideas of the three methods based on the Doppler-effect to obtain information on nuclear lifetimes and special kinematical details method and the ?-line angular distribution method/ are described. The circumstances under which the methods can experimentally be applied are also discussed. (P.L.)

  6. Determining the Speed of Sound Using the Doppler Effect.

    Science.gov (United States)

    Gagne, Richard.

    1996-01-01

    Presents a simple but effective experiment that uses ultrasonic transducers and some basic electronics to study the speed of sound using the Doppler effect. Eliminates the noise problems associated with most sound experiments. Discusses the theory, and describes the apparatus and procedure. (JRH)

  7. A range-rate extraction unit for determining Doppler effect

    Science.gov (United States)

    1970-01-01

    Active ranging technique devised for VHF or S-band radar systems divides target Doppler frequency by counter-generated number that is proportional to transmitting frequency, thus producing target velocity data in terms of speed and distance relative to target transponder.

  8. Unidirectional Rotation of Molecules Measured by the Rotational Doppler Effect

    OpenAIRE

    Prior Yehiam; Averbukh Ilya Sh; Gordon Robert; Steinitz Uri; Korech Omer

    2013-01-01

    A pair of linearly polarized pump pulses induce field-free unidirectional molecular rotation, which is detected by a delayed circularly polarized probe. The polarization and spectrum of the probe are modified by the interaction with the molecules, in accordance with the Rotational Doppler Effect.

  9. Complex Doppler effect in left-handed metamaterials

    OpenAIRE

    Ziemkiewicz, David; Zieli?ska-Raczy?ska, Sylwia

    2014-01-01

    The Doppler shift is investigated in one-dimensional system with moving source. Theoretical findings are confirmed in numerical simulations of optical and acoustical waves propagation in simple metamaterial model, showing the reversed shift and the existence of multiple frequency modes. The properties of these waves are discussed. The effect of absorption on the phenomenon is outlined.

  10. Relativistic Doppler effect in a uniformly accelerated motion - III

    OpenAIRE

    Paiva, F M; Teixeira, A. F. F.

    2008-01-01

    In the context of special relativity, we describe with detail the Doppler effect between a light source at rest and an observer in linear motion and constant proper acceleration. To have an Englis version of this article, ask the authors. ----- ^Ce special-relativeco ni detale priskribas lum-Doppleran efikon inter restanta fonto kaj observanto kun rektilinia movado kaj konstanta propra akcelo.

  11. Generalized Doppler effect in spaces with a transport along paths

    OpenAIRE

    Iliev, Bozhidar Z.

    2004-01-01

    An analog of the classical Doppler effect is investigated in spaces (manifolds) whose tangent bundle is endowed with a transport along paths, which, in particular, can be parallel one. The obtained results are valid irrespectively to the particles mass, i.e. they hold for massless particles (e.g. photons) as well as for massive ones.

  12. Method and system of doppler correction for mobile communications systems

    Science.gov (United States)

    Georghiades, Costas N. (Inventor); Spasojevic, Predrag (Inventor)

    1999-01-01

    Doppler correction system and method comprising receiving a Doppler effected signal comprising a preamble signal (32). A delayed preamble signal (48) may be generated based on the preamble signal (32). The preamble signal (32) may be multiplied by the delayed preamble signal (48) to generate an in-phase preamble signal (60). The in-phase preamble signal (60) may be filtered to generate a substantially constant in-phase preamble signal (62). A plurality of samples of the substantially constant in-phase preamble signal (62) may be accumulated. A phase-shifted signal (76) may also be generated based on the preamble signal (32). The phase-shifted signal (76) may be multiplied by the delayed preamble signal (48) to generate an out-of-phase preamble signal (80). The out-of-phase preamble signal (80) may be filtered to generate a substantially constant out-of-phase preamble signal (82). A plurality of samples of the substantially constant out-of-phase signal (82) may be accumulated. A sum of the in-phase preamble samples and a sum of the out-of-phase preamble samples may be normalized relative to each other to generate an in-phase Doppler estimator (92) and an out-of-phase Doppler estimator (94).

  13. Pediatric imaging/doppler ultrasound of the chest: Extracardiac diagnosis

    International Nuclear Information System (INIS)

    In this book the author spells out new diagnostic applications in pediatrics for high resolution cross-sectional ultrasonography, and demonstrates the ways in which Doppler techniques complement the cross-sectional method. This reference presents practical, step-by-step methods for non-invasive ultrasound examination of extra-cardiac anatomy and assessment of vascular blood flow

  14. Doppler sonography in diagnosis of the acute scrotum

    Directory of Open Access Journals (Sweden)

    Nikoli? Olivera

    2006-01-01

    Full Text Available Doppler sonography has been reported to be a reliable technique for diagnosing acute scrotum significantly decreasing the number of unnecessary surgeries. The aim of this paper was to demonstrate the superiority and validity of Doppler sonography over conventional sonography for differential diagnosis of the acute scrotum. In the period from 2002-2004, 300 patients underwent ultrasound examination of the testicles at the Institute of Radiology in Novi Sad. This prospective randomized study included 100 patients, whereas the target group consisted of 50 patients with the diagnosis of the acute scrotum. The control group consisted of 50 patients with the diagnosis of varicocele. The examinations were done using Siemens Versa Pro equipment and 7,5 MHz probes. On the basis of ultrasound examination, the target group was divided into three groups: 1. Inflammation, 2. Torsion, 3. Miscellaneous. Depending on the disease, the accuracy of diagnosis was confirmed by surgery, clinical findings and control sonographic examination. A functional correlation exists between Doppler diagnosis and final diagnosis in the inflammation and torsion. Resistive indexes (RI were lower in inflammation, because of hyperemia. In cases with intratesticular hyperemia, the average RI was 0,454 and in those with supratesticular hyperemia 0,575. In cases with torsion, only one patient with appendiceal torsion had normal intratesticular blood flow. In diagnostics of the acute scrotum, Doppler sonography is superior over conventional sonography and more precise in differential diagnostics. RI are good quantitative parameters of hyperemia. .

  15. Usefulness of Doppler Parameter in Patients with Renal Transplantation

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Yeo Chang; Shin, Byung Seok; Ohm, Joon Young; Ahn, Moon Sang [Chungnam National University Hospital, Daejeon (Korea, Republic of); Park, Mi Hyun [Dept. of Radiology, Dankook University Hospital, Cheonan (Korea, Republic of); Kim, Ho Jun [Dept. of Radiology, Konyang University Hospital, Daejeon (Korea, Republic of)

    2012-08-15

    The purpose of this study is to assess the usefulness of Doppler parameters in transplanted kidney function. Doppler parameters, including resistive index (RI), pulsatility index (PI), peak systolic velocity (PSV), and end diastolic velocity (EDV) were measured in the interlobar artery of 55 transplant recipients. Patients were grouped according to glomerular filtration rate (GFR): Group A (GFR < 30 ml / min / 1.73 m2, n = 27) and group B (GFR {>=}30 ml / min / 1.73 m2, n = 28). Doppler parameters were compared between groups and correlated with the GFR. GFR (40.1 {+-} 26.9) showed a significant negative correlation with RI (0.69{+-}.08) (p = .002, r = -.414). RI (0.72 vs. 0.67), PI (1.42 vs. 1.23), and EDV (10.5 vs. 15.3) differed significantly between groups (p < .05), however, PSV was not (36.9 vs. 47.1). Patients in group A (n = 11) with a lower RI than the mean had significantly lower PSV (31.7 vs. 45.1; p = .027) and EDV (11.1 vs. 16.7; p .017), compared with such patients in group B (n = 21). Doppler parameters are useful for evaluation of function of transplanted kidney. Even if the RI is normal, PSV and EDV may be used as hemodynamic indicators.

  16. Doppler reflectometry. Measuring the propagation velocity of density perturbations

    International Nuclear Information System (INIS)

    Doppler reflectometry is a radar measurement where a microwave signal probes the plasma with a line of sight which is non-perpendicular with respect to the reflecting layer. According to the Bragg condition the diagnostic selects density perturbations with finite wavevector Ksub(perpendicular) in the reflecting layer. From the Doppler shift of the returning microwave signal the propagation velocity ?sub(perpendicular) perpendicular to the magnetic field can be obtained whereas the signal intensity contains information about the perturbation amplitude. The diagnostic capability of Doppler reflectometry is discusses and results from the W7-AS stellarator are presented. During stationary phases the measured values ?sub(perpendicular)(r) and their radial dependence are in good agreement with the E x B velocity of the plasma obtained from passive spectroscopy. Transient states of the plasma can be followed with a temporal resolution of less than 50 ?s. Therefore Doppler reflectometry allows one to measure the interdependence of sheared flow and turbulence on that timescale. (author)

  17. Research on Fast-Doppler-Broadening of neutron cross sections

    International Nuclear Information System (INIS)

    A Fast-Doppler-Broadening method is developed in this work to broaden Continuous Energy neutron cross-sections for Monte Carlo calculations. Gauss integration algorithm and parallel computing are implemented in this method, which is unprecedented in the history of cross section processing. Compared to the traditional code (NJOY, SIGMA1, etc.), the new Fast-Doppler-Broadening method shows a remarkable speedup with keeping accuracy. The purpose of using Gauss integration is to avoid complex derivation of traditional broadening formula and heavy load of computing complementary error function that slows down the Doppler broadening process. The OpenMP environment is utilized in parallel computing which can take full advantage of modern multi-processor computers. Combination of the two can reduce processing time of main actinides (such as 238U, 235U) to an order of magnitude of 1?2 seconds. This new method is fast enough to be applied to Online Doppler broadening. It can be combined or coupled with Monte Carlo transport code to solve temperature dependent problems and neutronics-thermal hydraulics coupled scheme which is a big challenge for the conventional NJOY-MCNP system. Examples are shown to determine the efficiency and relative errors compared with the NJOY results. A Godiva Benchmark is also used in order to test the ACE libraries produced by the new method. (authors)

  18. Dead time effects in laser Doppler anemometry measurements

    DEFF Research Database (Denmark)

    Velte, Clara Marika; Buchhave, Preben; George, William K.

    2014-01-01

    We present velocity power spectra computed by the so-called direct method from burst-type laser Doppler anemometer (LDA) data, both measured in a turbulent round jet and generated in a computer. Using today’s powerful computers, we have been able to study more properties of the computed spectra...

  19. Ultrasonography and color Doppler in juvenile idiopathic arthritis

    DEFF Research Database (Denmark)

    Laurell, Louise; Court-Payen, Michel; Nielsen, Susan; Zak, Marek; Fasth, Anders

    2012-01-01

    The wrist region is one of the most complex joints of the human body. It is prone to deformity and functional impairment in juvenile idiopathic arthritis (JIA), and is difficult to examine clinically. The aim of this study was to evaluate the role of ultrasonography (US) with Doppler in diagnosis...

  20. Color Doppler in the Assessment of Uteroplacental Circulation Insufficiency

    Directory of Open Access Journals (Sweden)

    Ahmad Soltani Shirazi

    2010-05-01

    Full Text Available Usage of color Doppler ultrasound in the diagnosis of uteroplacental or fetal-placental vascular insufficiency is based on the theory that many of these insufficiencies are due to small vessel disease in the uteroplacental or fetal-placental vasculature which ultimately results in fetal intrauterine growth retardation, increase in prenatal mortality and morbidity and fetal neurological development. "nIn a prospective study on patients who were sus-pected for developing uteroplacental insufficiency, color Doppler ultrasound was done and the results were compared with neonatal weight (one of the most important criteria for IUGR determination which was measured just after delivery."nDirect significant relation was showed to be present between prepartum vascular changes detected in Doppler ultrasound and prognosis of IUGR. "nThree vessel types were assessed in this study:"n1. Umbilical-middle cerebral arteries"n2. Uterine arteries"n3.Venous system (umbilical, ductus venosus, IVC, which is used to assess the compensation process in fetal circulation."nThree Doppler indices of vascular resistance were studied and their abnormalities according to the age of pregnancy were assessed.

  1. Validar: A Testbed for Advanced 2-Micron Doppler Lidar

    Science.gov (United States)

    Koch, Grady J.; Petros, Mulugeta; Barnes, Bruce W.; Beyon, Jeffrey Y.; Amzajerdian, Farzin; Yu, Jirong; Kavaya, Michael J.; Singh, Upendra N.

    2004-01-01

    High-energy 2-microns lasers have been incorporated in a breadboard coherent Doppler lidar to test component technologies and explore applications for remote sensing of the atmosphere. Design of the lidar is presented including aspects in the laser transmitter, receiver, photodetector, and signal processing. Sample data is presented on wind profiling and CO2 concentration measurements.

  2. Low Cost Coherent Doppler Lidar Data Acquisition and Processing

    Science.gov (United States)

    Barnes, Bruce W.; Koch, Grady J.

    2003-01-01

    The work described in this paper details the development of a low-cost, short-development time data acquisition and processing system for a coherent Doppler lidar. This was done using common laboratory equipment and a small software investment. This system provides near real-time wind profile measurements. Coding flexibility created a very useful test bed for new techniques.

  3. Airborne Wind Profiling Algorithm for Doppler Wind LIDAR

    Science.gov (United States)

    Beyon, Jeffrey Y. (Inventor); Koch, Grady J. (Inventor); Kavaya, Michael J. (Inventor)

    2015-01-01

    Systems, methods, and devices of the present invention enable airborne Doppler Wind LIDAR system measurements and INS/GPS measurements to be combined to estimate wind parameters and compensate for instrument misalignment. In a further embodiment, the wind speed and wind direction may be computed based on two orthogonal line-of-sight LIDAR returns.

  4. High-Energy 2-Micrometers Doppler Lidar for Wind Measurements

    Science.gov (United States)

    Koch, Grady J.; Beyon, Jeffrey Y.; Barnes, Bruce W.; Petros, Mulugeta; Yu, Jirong; Amzajerdian, Farzin; Kavaya, Michael J.; Singh, Upendra N.

    2006-01-01

    High-energy 2-micrometer wavelength lasers have been incorporated in a prototype coherent Doppler lidar to test component technologies and explore applications for remote sensing of the atmosphere. Design of the lidar is presented including aspects in the laser transmitter, receiver, photodetector, and signal processing. Calibration tests and sample atmospheric data are presented on wind and aerosol profiling.

  5. Doppler Effect Associated with the Reflection of Light on a Moving Mirror

    OpenAIRE

    Rothenstein, Bernhard; Damian, Ioan

    2005-01-01

    The Doppler Effect associated with the reflection on a moving mirror is reduced to two Doppler Effect experiments involving the incoming incident ray and the outgoing reflected ray or vice-versa. The dependence of the corresponding Doppler factors on the incidence angle on the stationary mirror.

  6. Ductus Venosus Doppler Flow Velocity after Transplacental and Non-transplacental Amniocentesis during Midtrimester

    OpenAIRE

    Ulkumen, Burcu Artunc; Pala, Halil Gursoy; Baytur, Yesim Bulbul; Koyuncu, Faik Mumtaz

    2014-01-01

    Objective: We aimed to evaluate ductus venosus Doppler waveforms before and after amniocentesis in order to investigate any effect of amniocentesis on fetal myocardial hemodynamics. We also evaluated the umbilical artery, uterine artery and fetal mid-cerebral artery Doppler waveforms in order to investigate any relationship with ductus venosus Doppler changes.

  7. Predictable progressive Doppler deterioration in IUGR: does it really exist?

    LENUS (Irish Health Repository)

    Unterscheider, Julia

    2013-12-01

    An objective of the Prospective Observational Trial to Optimize Pediatric Health in IUGR (PORTO) study was to evaluate multivessel Doppler changes in a large cohort of intrauterine growth restriction (IUGR) fetuses to establish whether a predictable progressive sequence of Doppler deterioration exists and to correlate these Doppler findings with respective perinatal outcomes.

  8. Color Doppler Ultrasonography in Evaluation of the Postoperative Penis

    Directory of Open Access Journals (Sweden)

    M. Ghafouri

    2005-08-01

    Full Text Available Introduction & Background: Color Doppler ultrasonography (US is the imaging modality of choice in patients with penile diseases. Ultrasonography has a well-established role in evaluating erectile dysfunction as well as penile trauma, scarring, deformity, and tumors. The normal postoperative anatomy and the pathologic changes that can occur in cases of surgical complications can be successfully investigated with US. Gray Scale (B Mode and Color Doppler US clearly depicts the normal penile anatomy and postoperative changes. It is also effective in evaluating surgery-related complications and determining the causes of erectile dysfunction and other un-satisfactory long¬term results. Color Doppler US is the imaging modality of choice in evaluating patients who have undergone penile surgery. Here we aim to illustrate the gray-scale and color Doppler US appearance of normal penis, discuss the main penile surgical procedures, recognize the typical US features of the postopera-tive penis, and describe the US appearance of various postoperative complications. Patients & Methods: This article is the result of evaluating 42 patients referred to the radiology ward of Hashemi-Nejad Hospital, Iran University of Medical Sciences in the years 2002 to 2005 for ultrasonography of penis to assess the penis after different penile surgical procedures (urethral surgery, correction of penile mal-formations, prosthesis implantation, vascular surgery for impotence, surgical management of priapism, phallic reconstruction. The US apparatus was Esaote Technos MP, with linear multifrequency 5-8.5MHz. transducer. Results: A variety of early and late surgical complications could be identified, such as extraalbugineal patho-logic fluid collections and fibrosis. Moreover, Doppler US of the penile vessels and vascular anastomoses fol-lowing revascularization allowed direct evaluation of flow characteristics, shunt patency, and venous en-gorgement. Color Doppler US was also particularly helpful in determining the causes of erectile dysfunction and other unsatisfactory long-term results following penile surgery. Conclusion: Our findings indicate that color Doppler US is the imaging modality of choice in evaluating pa-tients who have undergone penile surgery because it clearly depicts normal penile anatomy and postoperative changes.

  9. Utero-placental Doppler ultrasound for improving pregnancy outcome

    Science.gov (United States)

    Stampalija, Tamara; Gyte, Gillian ML; Alfirevic, Zarko

    2014-01-01

    Background Impaired placentation can cause some of the most important obstetrical complications such as pre-eclampsia and intrauterine growth restriction and has been linked to increased fetal morbidity and mortality. The failure to undergo physiological trophoblastic vascular changes is reflected by the high impedance to the blood flow at the level of the uterine arteries. Doppler ultrasound study of utero-placental blood vessels, using waveform indices or notching, may help to identify the ‘at-risk’ women in the first and second trimester of pregnancy, such that interventions might be used to reduce maternal and fetal morbidity and/or mortality. Objectives To assess the effects on pregnancy outcome, and obstetric practice, of routine utero-placental Doppler ultrasound in first and second trimester of pregnancy in pregnant women at high and low risk of hypertensive complications. Search methods We searched the Cochrane Pregnancy and Childbirth Group’s Trials Register (June 2010) and the reference lists of identified studies. Selection criteria Randomised and quasi-randomised controlled trials of Doppler ultrasound for the investigation of utero-placental vessel waveforms in first and second trimester compared with no Doppler ultrasound. We have excluded studies where uterine vessels have been assessed together with fetal and umbilical vessels. Data collection and analysis Two authors independently assessed the studies for inclusion, assessed risk of bias and carried out data extraction. We checked data entry. Main results We found two studies involving 4993 participants. The methodological quality of the trials was good. Both studies included women at low risk for hypertensive disorders, with Doppler ultrasound of the uterine arteries performed in the second trimester of pregnancy. In both studies, pathological finding of uterine arteries was followed by low-dose aspirin administration. We identified no difference in short-term maternal and fetal clinical outcomes. We identified no randomised studies assessing the utero-placental vessels in the first trimester or in women at high risk for hypertensive disorders. Authors’ conclusions Present evidence failed to show any benefit to either the baby or the mother when utero-placental Doppler ultrasound was used in the second trimester of pregnancy in women at low risk for hypertensive disorders. Nevertheless, this evidence cannot be considered conclusive with only two studies included. There were no randomised studies in the first trimester, or in women at high risk. More research is needed to investigate whether the use of utero-placental Doppler ultrasound may improve pregnancy outcome. PMID:20824875

  10. Role of Doppler Velocimetry in growth restricted fetuses

    Directory of Open Access Journals (Sweden)

    Dr. Khushali Gandhi

    2015-01-01

    Full Text Available Background Intra Uterine Growth Restriction (IUGR is an important and particularly challenging problem for obstetricians and pediatricians. IUGR is a leading contributor in perinatal morbidity and mortality affecting 23.8% newborns around the world and 75% are born in Asia alone. In India the incidence of low birth weight varies from 15 to 25% and more than 50% of them are IUGR. Methods The present article consists of a study of 100 cases of intrauterine growth restriction with periodic color Doppler during the period of 1st July 2011 to 30 th August, 2013 in Obstetrics and Gynecology Department of a tertiary care center. Detail history taken. General and obstetrical examination was done along with routine hematological and urine investigations. Ultrasound examination was done for growth, liquor and placental localization. Fetal well- being was assessed with Doppler studies and daily fetal movement count. Results In present study moderate to severe pregnancy induced hypertension (53.9% and lack of proper weight gain (23% are found to be the commonest causes of IUGR. Out of 69 IUGR cases having abnormal Doppler, about 63.8% had abnormality in uterine artery flow, 85.5% had abnormality in umbilical artery flow, 88.4% had abnormality in middle cerebral artery flow, 55% had abnormality in uterine and umbilical artery and 75.4% had abnormality in umbilical artery and MCA. Incidence of fetal demise (13% was higher in patients with abnormal Doppler flow compared to normal flow (3.2%. Surgical intervention in form of caesarean was required in 69.6% of patients with abnormal Doppler flow. Cerebro-placental ratio (CPR 1 where fetal demise is 2.6%. Incidence of AEDF/REDF ( Absent End Diastolic flow/Reversed End diastolic flow in IUGR was 8% that resulted in 50% loss of fetus. Conclusions Color Doppler is a useful mode to predict fetal outcome in IUGR. Color Doppler allows better understandings of hemodynamic changes in feto- placental and utero-placental circulation. The cerebro-placental ratio (CPR, which measures the proportion of flow supplying the brain and placenta, is now the most powerful parameter for assessment of IUGR and hypoxia.

  11. Hydronephrosis and pregnancy: study with Doppler echography. Hidronefrosis y embarazo: estudio mediante ecografia Doppler

    Energy Technology Data Exchange (ETDEWEB)

    Ripolles Gonzalez, T.R.; Ambit Capdevilla, S.; Sanguesa Nebot, C.; Lazaro, S. de; Garcia Vila, J.H.; Belloch Ugarte, V.

    1993-01-01

    An 18-month study was performed to establish the normal intrarenal resistance index during pregnancy, in order to determine whether it differed significantly depending on the week of gestation or the degree of hydronephrosis. For this purpose , the flow velocity waves obtained in right kidney were analyzed in a group of 112 patients on the basis of 209 explorations. The kidneys were classified as grade 0,I,II, or III according to the degree of hydronephrosis. Doppler signal sampling was carried out at the level of the corticomedullary junction. From the results of the study it can be deduced that the index of intrarenal resistance during pregnancy is similar to that of the general population, that there are no significant differences among the groups with different degree of hydronephrosis and that the index does not vary according to the different weeks of gestation. These findings suggest that, during pregnancy, a pathological resistance index in a kidney should not be attributed to the physiological changes associated with normal gestation. (Author) 21 refs.

  12. Non-Gaussianity and CMB aberration and Doppler

    Energy Technology Data Exchange (ETDEWEB)

    Catena, Riccardo [Institut für Theoretische Physik, Friedrich-Hund-Platz 1, 37077 Göttingen (Germany); Liguori, Michele; Renzi, Alessandro [INFN, Sezione di Padova, Via Marzolo 8, 35131 Padova (Italy); Notari, Alessio, E-mail: riccardo.catena@theorie.physik.uni-goettingen.de, E-mail: michele.liguori@pd.infn.it, E-mail: notari@ffn.ub.es, E-mail: arenzi@pd.infn.it [Departament de Física Fondamental i Institut de Ciéncies del Cosmos, Universitat de Barcelona, Martí i Franqués 1, 08028 Barcelona (Spain)

    2013-09-01

    The peculiar motion of an observer with respect to the CMB rest frame induces a deflection in the arrival direction of the observed photons (also known as CMB aberration) and a Doppler shift in the measured photon frequencies. As a consequence, aberration and Doppler effects induce non trivial correlations between the harmonic coefficients of the observed CMB temperature maps. In this paper we investigate whether these correlations generate a bias on non-Gaussianity estimators f{sub NL}. We perform this analysis simulating a large number of temperature maps with Planck-like resolution (lmax = 2000) as different realizations of the same cosmological fiducial model (WMAP7yr). We then add to these maps aberration and Doppler effects employing a modified version of the HEALPix code. We finally evaluate a generalization of the Komatsu, Spergel and Wandelt non-Gaussianity estimator for all the simulated maps, both when peculiar velocity effects have been considered and when these phenomena have been neglected. Using the value v/c = 1.23 × 10{sup ?3} for our peculiar velocity, we found that the aberration/Doppler induced non-Gaussian signal is at most of about half of the cosmic variance ? for f{sub NL} both in a full-sky and in a cut-sky experimental configuration, for local, equilateral and orthogonal estimators. We conclude therefore that when estimating f{sub NL} it is safe to ignore aberration and Doppler effects if the primordial map is already Gaussian. More work is necessary however to assess whether a map which contains non-Gaussianity can be significantly distorted by a peculiar velocity.

  13. Doppler ultrasound scan during normal gestation: umbilical circulation

    International Nuclear Information System (INIS)

    To determine normal umbilical circulation patterns by means of Doppler ultrasound scan in a healthy gestating population without risk factors and with normal perinatal results, and to evaluate any occurring modifications relative to gestational age by obtaining records kept during pregnancy. One hundred and sixteen pregnant women carrying a single fetus have been studied. These women had no risk factors, with both clinical and analytical controls, as well as ultrasound scans, all being normal. There were performed a total of 193 Doppler ultrasound scans between weeks 15 and 41 of gestation, with blood-flow analysis in the arteries and vein of the umbilical cord. The obtained information was correlated with parameters that evaluate fetal well-being (fetal monitoring and/or oxytocin test) and perinatal result (delivery type, birth weight, Apgar score). Statistical analysis was performed with the programs SPSS 6.0.1 for Windows and EPIINFO 6.0.4. With pulsed Doppler, the umbilical artery in all cases demonstrated a biphasic morphology with systolic and diastolic components and without retrograde blood flow. As the gestation period increased, there was observed a progressive decrease in resistance along with an increase in blood-flow velocity during the diastolic phase. The Doppler ultrasound scan is a non-invasive method that permits the hemodynamic study of umbilical blood circulation. A knowledge of normal blood-flow signal morphology, as well as of the normal values for Doppler indices in relation to gestational age would permit us to utilize this method in high-risk pregnancies. (Author) 30 refs

  14. Investigating the robustness of the new Landsat-8 Operational Land Imager derived texture metrics in estimating plantation forest aboveground biomass in resource constrained areas

    Science.gov (United States)

    Dube, Timothy; Mutanga, Onisimo

    2015-10-01

    The successful launch of the 30-m Landsat-8 Operational Land Imager (OLI) pushbroom sensor offers a new primary data source necessary for aboveground biomass (AGB) estimation, especially in resource-limited environments. In this work, the strength and performance of Landsat-8 OLI image derived texture metrics (i.e. texture measures and texture ratios) in estimating plantation forest species AGB was investigated. It was hypothesized that the sensor's pushbroom design, coupled with the presence of refined spectral properties, enhanced radiometric resolution (i.e. from 8 bits to 12 bits) and improved signal-to-noise ratio have the potential to provide detailed spectral information necessary for significantly strengthening AGB estimation in medium-density forest canopies. The relationship between image texture metrics and measurements of forest attributes can be used to help characterize complex forests, and enhance fine vegetation biophysical properties, a difficult challenge when using spectral vegetation indices especially in closed canopies. This study examines the prospects of using Landsat-8 OLI sensor derived texture metrics for estimating AGB for three medium-density plantation forest species in KwaZulu Natal, South Africa. In order to achieve this objective, three unique data pre-processing techniques were tested (analysis I: Landsat-8 OLI raw spectral-bands vs. raw texture bands; analysis II: Landsat-8 OLI raw spectral-band ratios vs. texture band ratios and analysis III: Landsat-8 OLI derived vegetation indices vs. texture band ratios). The landsat-8 OLI derived texture parameters were examined for robustness in estimating AGB using linear regression, stepwise-multiple linear regression and stochastic gradient boosting regression models. The results of this study demonstrated that all texture parameters particularly band texture ratios calculated using a 3 × 3 window size, could enhance AGB estimation when compared to simple spectral reflectance, simple band ratios and the most popular spectral vegetation indices. For instance, the use of combined texture ratios yielded the highest R2 values of 0.76 (RMSE = 9.55 t ha-1 (18.07%) and CV-RMSE of 0.18); 0.74 (RMSE = 12.81 t ha-1 (17.72%) and CV-RMSE of 0.08); 0.74 (RMSE = 12.67 t ha-1 (06.15%) and CV-RMSE of 0.06) and 0.53 (RMSE = 20.15 t ha-1 (14.40%) and CV-RMSE of 0.15) overall for Eucalyptus dunii, Eucalyptus grandis, Pinus taeda individually and all species, respectively. Overall, the findings of this study provide the necessary insight and motivation to the remote sensing community, particularly in resource constrained regions, to shift towards embracing various texture metrics obtained from the readily-available and cheap multispectral Landsat-8 OLI sensor.

  15. Doppler tisular y estratificación del riesgo en la miocardiopatía hipertrófica / Tissue Doppler and Risk Stratification in Hypertrophic Cardiomyopathy

    Scientific Electronic Library Online (English)

    Juan P., Ochoa; Adrián, Fernández; Juan M., Filipuzzi; Agostina M., Fava; José H., Casabé; Fabián, Salmo; Fabián, Vaisbuj; Horacio J., Di Nunzio; Guillermo, Ganum; Eduardo, Guevara.

    2014-04-01

    Full Text Available Introducción El Doppler pulsado tisular ha demostrado beneficio en la detección temprana de la miocardiopatía hipertrófica y en el diagnóstico diferencial de esta con otras causas secundarias de hipertrofia. Objetivo Determinar el valor pronóstico de las velocidades miocárdicas sistólicas tisulares [...] preservadas en pacientes con diagnóstico de miocardiopatía hipertrófica. Material y métodos Se incluyeron 146 pacientes con diagnóstico de miocardiopatía hipertrófica, los cuales fueron evaluados en forma prospectiva mediante un estudio de ecocardiograma Doppler. Se obtuvieron las velocidades sistólicas tisulares del promedio de las velocidades septales y laterales; se compararon los pacientes con velocidades miocárdicas sistólicas tisulares preservadas (Sa = 8 cm/seg; cuartil superior) con los que presentaban velocidades disminuidas. Se definió como punto final primario a la presencia de muerte súbita, accidente cerebrovascular, insuficiencia cardíaca o internación de causa cardiovascular en el seguimiento. Resultados El 29% (n = 43) presentó velocidades miocárdicas sistólicas tisulares preservadas en las imágenes del Doppler tisular, con más frecuencia de varones (76,7% vs. 53,4%; p = 0,009) y sin diferencias en la edad. Los diámetros ventriculares y los espesores fueron similares, en tanto que el área auricular fue significativamente menor (23,7 ± 6,7 cm² vs. 28,8 ± 8 cm²; p Abstract in english Usefulness of Tissue Doppler Imaging to Identify Low Risk Patients with Diagnosis of Hypertrophic Cardiomyopathy Background Pulsed tissue Doppler imaging is a useful tool for the early detection of hypertrophic cardiomyopathy and the differential diagnosis of this disease from other secondary causes [...] of hypertrophy. Objective The aim of the study was to determine the prognostic significance of preserved systolic tissue velocities in patients with diagnosis of hypertrophic cardiomyopathy. Methods One hundred and forty six patients with diagnosis of hypertrophic cardiomyopathy were prospectively included by means of a Doppler echocardiography study. Systolic tissue velocities were obtained from the averaged septal and lateral velocities. Patients with preserved systolic tissue velocities (Sa = 8 cm/s; upper quartile) were compared with those presenting decreased velocities. The primary endpoint was defined as the presence of sudden death, stroke, heart failure, or hospitalization for cardiovascular causes at follow up. Results Twenty nine percent of patients (n = 43) presented preserved systolic tissue velocities in the tissue Doppler images, mostly in men (76.7% vs. 53.4%, p = 0.009) and with no age differences. Ventricular diameter and thickness were similar between the two groups while the atrial area was significantly lower (23.7 ± 6.7 vs. 28.8 ± 8, p

  16. Valoración por ultrasonografía Doppler en medicina materno-fetal / Doppler ultrasonography assessment in maternal-foetal medicine

    Scientific Electronic Library Online (English)

    Pablo Andrés, Victoria-Gómez.

    2006-09-01

    Full Text Available Introducción y objetivo: desde la década del 80, las técnicas de ecografía Doppler han permitido en-tender de manera más precisa la hemodinamia fetoplacentaria y sus variantes fisiológicas. Igualmente han ayudado a reconocer los cambios patológicos generados en el feto ante diferentes tipos de lesió [...] n, permitiendo actuar de forma oportuna y así impactar de manera importante en la disminución de los índices de morbilidad y mortalidad neonatal. El objetivo de la siguiente revisión es ofrecer al médico una visión clara y concisa de las utilidades de la ecografía Doppler, lo cual le permitirá aplicarla en su práctica diaria. Métodos: se realizó una búsqueda bibliográfica en diferentes bases de datos electrónicas (Pubmed, Ovid, Elsevier, Interscience, Cochrane) y libros de texto impresos, tratando de encontrar la mejor evidencia respecto a las utilidades de la ecografía Doppler. Hallazgos de la revisión: la ecografía Doppler se ha convertido en un instrumento diagnóstico de gran aplicación en el campo de la medicina materno-fetal. Hoy en día es clave para el diagnóstico y seguimiento de fetos con anemia o con restricción del crecimiento fetal, tamizaje de aneuploidías realizado en el primer trimestre del embarazo, estudio de morfología fetal, diagnóstico de accretismo placentario, detección temprana de infección fetal y tamizaje para patologías derivadas de insuficiencia útero-placentaria (retardo del crecimiento intrauterino [RCIU] y preeclampsia) así como resultado perinatal adverso. Conclusión: la ecografía Doppler es una herramienta diagnóstica que ha revolucionado la perinatología, ya que ha permitido disminuir de manera importante los procedimientos invasivos en el feto, así como conocer de manera clara los cambios fisiológicos que se dan en la unidad feto-placentaria, entre otras utilidades. Abstract in english Introduction: Doppler ultrasound techniques (available since the 1980s) have allowed a more precise understanding of foetal-placental haemodynamics and their physiological variants. They have also helped in recognising pathological changes produced in the foetus by different types of injury, allowin [...] g more precise action to be taken and decreasing neonatal morbidity and mortality. This article is aimed at offering a comprehensive review of Doppler technology in perinatal medicine and pointing out its practical usefulness in current obstetric practice. Methods: electronic databases (PubMed, Ovid, Elsevier, InterScience, Cochrane) and text books were reviewed to obtain the best evidence regarding using Doppler technology in perinatal medicine. Results: Doppler ultrasonography has become a diagnostic tool having wide application in the field of maternal-foetal medicine. It is currently the key for diagnosing and managing foetuses affected by anaemia or foetal growth restriction (FGR), chromosomal abnormality screening during the first three months of pregnancy, studying foetal morphology, diagnosing placenta accreta, the early detection of foetal infection and screening for utero-placental insufficiency-derived pathologies (FGR and preeclampsia) and adverse perinatal outcomes. Conclusion: Doppler ultrasonography used as a diagnostic tool has changed perinatal practice, allowing more precise handling of invasive foetal procedures (as well as reducing them) and giving us a better understanding of the physiological changes occurring at foetal-placental level.

  17. Valoración por ultrasonografía Doppler en medicina materno-fetal Doppler ultrasonography assessment in maternal-foetal medicine

    Directory of Open Access Journals (Sweden)

    Pablo Andrés Victoria-Gómez

    2006-09-01

    Full Text Available Introducción y objetivo: desde la década del 80, las técnicas de ecografía Doppler han permitido en-tender de manera más precisa la hemodinamia fetoplacentaria y sus variantes fisiológicas. Igualmente han ayudado a reconocer los cambios patológicos generados en el feto ante diferentes tipos de lesión, permitiendo actuar de forma oportuna y así impactar de manera importante en la disminución de los índices de morbilidad y mortalidad neonatal. El objetivo de la siguiente revisión es ofrecer al médico una visión clara y concisa de las utilidades de la ecografía Doppler, lo cual le permitirá aplicarla en su práctica diaria. Métodos: se realizó una búsqueda bibliográfica en diferentes bases de datos electrónicas (Pubmed, Ovid, Elsevier, Interscience, Cochrane y libros de texto impresos, tratando de encontrar la mejor evidencia respecto a las utilidades de la ecografía Doppler. Hallazgos de la revisión: la ecografía Doppler se ha convertido en un instrumento diagnóstico de gran aplicación en el campo de la medicina materno-fetal. Hoy en día es clave para el diagnóstico y seguimiento de fetos con anemia o con restricción del crecimiento fetal, tamizaje de aneuploidías realizado en el primer trimestre del embarazo, estudio de morfología fetal, diagnóstico de accretismo placentario, detección temprana de infección fetal y tamizaje para patologías derivadas de insuficiencia útero-placentaria (retardo del crecimiento intrauterino [RCIU] y preeclampsia así como resultado perinatal adverso. Conclusión: la ecografía Doppler es una herramienta diagnóstica que ha revolucionado la perinatología, ya que ha permitido disminuir de manera importante los procedimientos invasivos en el feto, así como conocer de manera clara los cambios fisiológicos que se dan en la unidad feto-placentaria, entre otras utilidades.Introduction: Doppler ultrasound techniques (available since the 1980s have allowed a more precise understanding of foetal-placental haemodynamics and their physiological variants. They have also helped in recognising pathological changes produced in the foetus by different types of injury, allowing more precise action to be taken and decreasing neonatal morbidity and mortality. This article is aimed at offering a comprehensive review of Doppler technology in perinatal medicine and pointing out its practical usefulness in current obstetric practice. Methods: electronic databases (PubMed, Ovid, Elsevier, InterScience, Cochrane and text books were reviewed to obtain the best evidence regarding using Doppler technology in perinatal medicine. Results: Doppler ultrasonography has become a diagnostic tool having wide application in the field of maternal-foetal medicine. It is currently the key for diagnosing and managing foetuses affected by anaemia or foetal growth restriction (FGR, chromosomal abnormality screening during the first three months of pregnancy, studying foetal morphology, diagnosing placenta accreta, the early detection of foetal infection and screening for utero-placental insufficiency-derived pathologies (FGR and preeclampsia and adverse perinatal outcomes. Conclusion: Doppler ultrasonography used as a diagnostic tool has changed perinatal practice, allowing more precise handling of invasive foetal procedures (as well as reducing them and giving us a better understanding of the physiological changes occurring at foetal-placental level.

  18. Doppler detection of decompression bubbles with computer assisted digitization of ultrasonic signals

    Science.gov (United States)

    Butler, B. D.; Robinson, R.; Fife, C.; Sutton, T.

    1991-01-01

    The use of an inexpensive, commercially available audio digitizer in conjunction with a PC to digitize Doppler bubble signals for visual and electronic evaluation is reported. This device can be operated simultaneously with Doppler audio monitoring. Precordial and arterial Doppler recordings of gas bubbles were obtained from anesthetized dogs after intravascular infusion or following decompression. Additional evaluations were conducted on Doppler bubble recordings obtained from human decompression studies. The device can be used in real-time or for later signal analysis. Accompanying menu-driven software provides for numerous signal modification options and visual displays. This device can provide a simultaneous visual display of Doppler signals normally available only for audio evaluation.

  19. Spaceborne Simulations of Two Direct-Detection Doppler Lidar Techniques

    Science.gov (United States)

    McGill, Matthew J.; Li, Steve X.

    1998-01-01

    Direct-detection (or incoherent) lidar is now a proven technique for measuring winds in the atmosphere. Over the last few years, several types of direct-detection lidar have evolved. These methods rely on Fabry-Perot interferometers(also termed etalons) or other narrow-passband filters to provide the required spectral resolution. One method, now called the edge (EDG) technique, uses a sharply-sloping filter and measures changes in the filter transmission caused by Doppler shifting of the laser wavelength. A variation of the EDG method, called the double-edge (DEDG) technique, uses two filters. The molecular DEDG method was first demonstrated by Chanin et al. for stratospheric measurements and more recently Korb et al. successfully demonstrated the aerosol DEDG through the troposphere. A second method, here termed the multi-channel (MC) technique, measures Doppler shifts by observing angular displacement of a Fabry-Perot fringe in a spatially resolving detector. The EDG technique thus employs the Fabry-Perot to convert the frequency shift into an amplitude signal, while the MC technique uses the Fabry-Perot to resolve the spectral signature which is then fitted to determine the centroid. The focus of this presentation is on the DEDG and MC methods because these are viewed as the current state of the art in direct-detection lidar. Successful ground-based demonstrations of direct-detection wind measurements have resulted in proposals for spaceborne systems. With this new emphasis on spaceborne systems comes the need for accurate prediction of spaceborne direct-detection Doppler lidar performance. Previously, the EDG and MC methods have been compared although only for aerosol Doppler systems. A recent paper by McGill and Spinhirne compares the DEDG and MC methods in a non-system specific manner for both the aerosol and molecular Doppler systems. The purpose of this presentation is to extend the previous work of McGill and Spinhirne to examine the performance of spaceborne profiling systems. Particular emphasis will be placed on the molecular systems, as these are viewed as the strength of direct-detection Doppler lidar.

  20. Rain Fallspeeds and Rates Derived from Airborne Nadir-Pointing Doppler Radar Measurements

    Science.gov (United States)

    Heymsfield, Gerald M.; Tian, L.; Geerts, Bart

    1999-01-01

    The use of vertical-incidence Doppler velocity in addition to radar reflectivity may yield information on drop size distribution and therefore result in better rainrate estimates. Doppler velocity can provide useful information on the raindrop size distribution. Doppler velocities from a zenith-pointing radar represent the sum of the mean reflectivity-weighted hydrometeor fallspeed and the vertical air motion. Dual-parameter rain estimation methods using the Doppler velocity, require that the latter can be removed, or is negligible. Atlas et al. (1972) derived relations between Doppler velocity, reflectivity, and rain rate assuming an exponential size distribution for rain. Ulbrich (1994) expanded on this work by deriving the relation between the Doppler velocity and the reflectivity assuming a Gamma size distribution. This distribution provides a more realistic representation of the small rain drops. To get accurate information on raindrop size distributions with the above method, the air motions must be removed from the observed Doppler velocities

  1. Multipath-dominant, pulsed doppler analysis of rotating blades

    CERN Document Server

    Robinson, Michael

    2012-01-01

    We present a novel angular fingerprinting algorithm for detecting changes in the direction of rotation of a target with a monostatic, stationary sonar platform. Unlike other approaches, we assume that the target's centroid is stationary, and exploit doppler multipath signals to resolve the otherwise unavoidable ambiguities that arise. Since the algorithm is based on an underlying differential topological theory, it is highly robust to distortions in the collected data. We demonstrate performance of this algorithm experimentally, by exhibiting a pulsed doppler sonar collection system that runs on a smartphone. The performance of this system is sufficiently good to both detect changes in target rotation direction using angular fingerprints, and also to form high-resolution inverse synthetic aperature images of the target.

  2. Novel Doppler laser radar for diagnostics in fusion reactors

    International Nuclear Information System (INIS)

    We describe the development of a novel Doppler laser radar (DOLAR) for remote measurement of flow velocity (0-10 m/s) and film thickness of liquid metal walls, currently being studied for their superior heat handling and self-healing characteristics. Small fluctuations in flow velocity(∼mm/s) and flow thickness (∼50 μm) that may arise during plasma discharges can also be measured. The DOLAR is also designed for non intrusive mapping of features of plasma-facing solid surfaces with very high precision (∼50 μm). It can also measure the motion of structural components of a fusion reactor during plasma discharges and during plasma disruptions. The device utilizes frequency modulation laser radar principles for precision range measurements. Compensation of Doppler frequency shift is used to measure flow velocity. The DOLAR probe head is designed with acousto-optic and piezoelectric devices for operation in the harsh fusion environment

  3. System-on-chip based Doppler radar occupancy sensor.

    Science.gov (United States)

    Yavari, Ehsan; Song, Chenyan; Lubecke, Victor; Boric-Lubecke, Olga

    2011-01-01

    System-on-Chip (SoC) based Doppler radar occupancy sensor is developed through non contact detection of respiratory signals. The radio was developed using off the shelf low power RF CC2530 SoC chip by Texas Instruments. In order to save power, the transmitter sends signal intermittently at 2.405 GHz. Reflected pulses are demodulated, and the baseband signals are processed to recover periodic motion. The system was tested both with mechanical target and a human subject. In both cases Doppler radar detected periodic motion closely matched the actual motion, and it has been shown that an SoC based system can be used for subject detection. PMID:22254705

  4. Doppler radar fall activity detection using the wavelet transform.

    Science.gov (United States)

    Su, Bo Yu; Ho, K C; Rantz, Marilyn J; Skubic, Marjorie

    2015-03-01

    We propose in this paper the use of Wavelet transform (WT) to detect human falls using a ceiling mounted Doppler range control radar. The radar senses any motions from falls as well as nonfalls due to the Doppler effect. The WT is very effective in distinguishing the falls from other activities, making it a promising technique for radar fall detection in nonobtrusive inhome elder care applications. The proposed radar fall detector consists of two stages. The prescreen stage uses the coefficients of wavelet decomposition at a given scale to identify the time locations in which fall activities may have occurred. The classification stage extracts the time-frequency content from the wavelet coefficients at many scales to form a feature vector for fall versus nonfall classification. The selection of different wavelet functions is examined to achieve better performance. Experimental results using the data from the laboratory and real inhome environments validate the promising and robust performance of the proposed detector. PMID:25376033

  5. Doppler reflectometry for the investigation of poloidally propagating density perturbations

    International Nuclear Information System (INIS)

    A modification of microwave reflectometry is discussed where the direction of observation is tilted with respect to the normal onto the reflecting surface. The experiment is similar to scattering where a finite resolution in k-space exists but keeps the radial localization of reflectometry. The observed poloidal wavenumber is chosen by Bragg's condition via the tilt angle and the resolution in k-space is determined by the antenna pattern. From the Doppler shift of the reflected wave the poloidal propagation velocity of density perturbations is obtained. The diagnostic capabilities of Doppler reflectometry are investigated using full wave code calculations. The method offers the possibility to observe changes in the poloidal propagation velocity of density perturbations and their radial shear with a temporal resolution of about 10μs. (authors)

  6. Assessment of right ventricular systolic function by tissue Doppler echocardiography

    DEFF Research Database (Denmark)

    Kjærgaard, Jesper

    2012-01-01

    This thesis summarizes a series of studies performed in order to assess the clinical usefulness of a novel echocardiographic technology that allows non-invasive assessment of regional right ventricular myocardial velocities and deformation: tissue Doppler echocardiography. While the technology is a promising tool for improving our understanding of right ventricular hemodynamics, several aspects of the technology must be evaluated. The accuracy and reproducibility of the technology is evaluated in vitro, and normal values, impact of changes in loading of the right ventricle, response to exercise and pharmacological pulmonary vasodilatation is established in normal subjects. The diagnostic and prognostic importance of adding tissue Doppler echocardiography to conventional echocardiographic and clinical parameters was evaluated in studies on patients with diseases associated with different modes of impact on right ventricular hemodynamics: pulmonary embolism, Arrhythmogenic right ventricular cardiomyopathy and pulmonary regurgitation, the latter in an animal model. The conclusions of the thesis are: Color tissue Doppler echocardiography accurately measures velocities, SR and strain in vitro. No systematic bias between ultrasound systems can be found, and accuracy of the measurements is good. However, the reproducibility of measurements in a test-retest design can limit the usefulness of the technology in daily clinical use, as 25% to 80% of change would be needed for the technology to identify a change in individual patients [I]. Normal values of tissue Doppler based measurements of RV regional velocities, SR and strain exist, and apply to both sexes and in all age groups with the exception of slightly decreasing values in strain with increasing age. Increasing preload and afterload changes regional myocardial velocities, but no changes in SR, strain or isovolumic acceleration could be observed [II and III]. Tissue Doppler echocardiography of the RV free wall in non-massive pulmonary embolism quantifies degree of RVdysfunction, and supports the existence of the McConnell sign of mid-ventricular RV dysfunction. Echocardiographic signs of RV dysfunction are present if > 25% of the pulmonary vascular bed is obstructed. However, Tissue Doppler echocardiography and deformation analysis has no independent value over other clinical and quantitative echocardiographic measures of RV size, pressure and function in these patients [IV and V]. Regional deformation of the RV free wall has significant prognostic importance in a population suspected of first non-massive pulmonary embolism, and is significantly associated with adverse events in patients with proven pulmonary embolism, however, it does not add to the information gained from other quantitative echocardiographic measures of LV and RV function and pressure [VI]. Changes in tissue Doppler based measures of RV systolic function can be used to monitor the effect of selective vasodilation by phosphodiestares-5 inhibition in hypoxic pulmonary hypertension and exercise in normalindividuals. Phosphodiestares-5 inhibition by sildenafil may predominantly be effective during hypoxia in resting conditions, and may improve the blunted response in RV contractility seen with exercise in hypoxia [VII]. Reduced RV free wall deformation can be quantified by tissue Doppler echocardiography in patients with confirmed Arrhythmogenic Right Ventricular Cardiomyopathy, but the clinical application of the technique may be limited by considerable overlap with normal values [VIII]. Acute RV volume loading in free pulmonary regurgitation is associated with abrupt geometric changes in the RV structure including significant dilatation, but is well tolerated with only mild reduction in measures of global RV systolic function as estimated by 2D echocardiography in an experimental animal model. Regional RV myocardial function is also only mildly reduced. Also no differences in global or regional RV function can be observed after 1-3 months of pulmonary regurgitation [IX and X]. Relief of free pulmonary regurg

  7. A reliable Doppler-based solution for single sensor geolocation

    Science.gov (United States)

    Witzgall, H.

    This paper examines the ability of particle filters to provide accurate Doppler-based frequency of arrival (FOA) geolocation of radio frequency (RF) emitters. Most existing non-differential Doppler geolocation techniques simplify their geolocation solution by assuming that the emitter's carrier frequency is unknown but stable over the course of the triangulation. This assumption is often violated by today's commercial devices whose applications allow for significant carrier frequency drift, with the result of erroneous FOA solutions. The proposed approach uses particles to discretely represent a state's hypothesized emitter location and conditionally updates the particle's associated frequency drift based on that location and the observations. The performance of this approach is examined for the case of a relatively slow-moving unmanned aerial vehicle (UAV). The results show it is significantly more accurate and robust than Newton's iterative gradient descent techniques, and closely approaches the FOA Cramer-Rao lower bound (CRLB) for location estimation.

  8. SIGACE, Code for Doppler broadening of ACE-formatted files

    International Nuclear Information System (INIS)

    1 - Description of program or function: SIGACE provides a method for generating high temperature ACE files for use with the MCNP code starting with a lower temperature file. IAEA1416/01: The code has been adapted to run under Linux. 2 - Methods: The low temperature ACE file is first converted to ENDF formatted file using the ACELST code and then Doppler broadened, essentially limited to the data in the resolved resonance region, to any desired higher temperature using SIGMA1. The SIGACE code then generates a high temperature ACE file for use with the MCNP code. A thinning routine has also been introduced in the SIGACE code for reducing the size of the ACE files. The Doppler Broadened ACE file can then again be converted to ENDF file and graphically plotted using EVALPLOT and compared with other ENDF file using COMPLOT routines of the PREPRO code system for validation purposes

  9. Pulsed doppler analysis of human fetal blood flow

    International Nuclear Information System (INIS)

    Echocardiographic imaging techniques have been applied successfully for the diagnosis of structural heart disease in the second- and third-trimester human fetus. These studies have also provided structural information that has increased our understanding of normal fetal cardiac development, had have furthered our concepts of the pathophysiology of congenital heart disease. The application of pulsed Doppler technology for examination of the fetal cardiovascular system offers the promise of increasing our understanding of fetal cardiovascular development, by providing information concerning directional blood flow, as well as estimates of volume flow within the fetus. It is the purpose of this report to review the experience that has been amassed in the application of pulsed Doppler technology for the analysis of blood flow within the human fetus

  10. Distribution of Doppler Redshifts of Associated Absorbers of SDSS Quasars

    Indian Academy of Sciences (India)

    Cai-Juan Pan; Zhi-Fu Chen

    2013-12-01

    Doppler redshifts of a sample of Mg II associated absorbers of SDSS DR7 quasars are analysed. We find that there might be three Gaussian components in the distribution of the Doppler redshift. The first Gaussian component, with the peak being located at Dopp = -0.0074, probably arises from absorbers with outflow histories observed in the direction close to jets of quasars. The second Gaussian component, with the peak being located at Dopp = -0.0017, possibly arises from absorbers with outflow histories observed in the direction far away from jets of quasars. Whereas, the third Gaussian component, with the peak being located at Dopp = -0.0004, might arise from the random motion of absorbers with respect to quasars.

  11. Ballistic Missile Warhead Recognition based on Micro-Doppler Frequency

    Directory of Open Access Journals (Sweden)

    Sun Hui-Xia

    2008-11-01

    Full Text Available To elucidate the spinning-precession signatures of ballistic warhead, the model of spinning precessionfor ballistic missile warhead is established and the mathematics of micro-Doppler signatures caused by spinning-precession is derived. Then the micro-Doppler features are analysed using high-resolution time-frequencytransform, and the model predictions match the experimental data well. Based on  different mass of warheadsand decoys, the feature, which can reflect the mass of the targets, is extracted from the time-frequency plane,proving a new method for recognising warheads and discriminating these from decoys. Finally the validityof the feature extracted in this study is verified by computer simulations even with low signal-to-noise ratio.Defence Science Journal, 2008, 58(6, pp.705-709, DOI:http://dx.doi.org/10.14429/dsj.58.1697

  12. Gravitational Doppler effect explored by means of a geostationary satellite

    International Nuclear Information System (INIS)

    The question is discussed whether the description of the gravitational Doppler effect as a simple energy effect is consistent with its general-relativistic description as a metricntime effect. The difference between a local description and a global one is stressed. In the local description one is permitted to ignore metric effects. The global description yields a position-dependent rate of proper time in a gravitational field, and the energy, or the frequency, of a ''freely falling'' photon is described as a constant of motion. An experiment of nonlocal character measuring, simultaneously, the gravitational Doppler effect and the position-dependent rate of proper time may be performed by the use of a geostationary satellite. A simple general-relativistic of the satellite experiment is obtained by transforming the Schwarzschild metric to a rotating frame, and describing the motion of free particles nd the rates of standard clocks in the resulting metric

  13. Doppler broadening measurements in FRX-C/LSM

    International Nuclear Information System (INIS)

    Measurements obtained in situ during field reversed configuration (FRC) formation show that the Doppler broadening ion temperature TCV is larger by a factor of two or more than the ion temperature Ti derived from pressure balance and Thomson scattering. After a time comparable to an ion-ion equilibrium time, TCV and Ti come into agreement with each other. An exception to this picture occurs in the lowest fill pressure condition (2 mtorr), for which TCV > Ti is maintained throughout the FRC lifetime. Earlier Doppler broadening measurements in FRX-B and FRX-C also showed persistent, anomalously high TCV at low fill pressure. The initially high values of TCV are probably caused by convective motion generated by the radial implosion. The low fill pressure results suggest an enhanced ohmic power input to the carbon ions. 7 refs., 3 figs

  14. Gravity theories, Transverse Doppler and Gravitational Redshifts in Galaxy Clusters

    CERN Document Server

    Zhao, Hongsheng; Li, Baojiu

    2012-01-01

    There is growing interest in testing alternative gravity theories using the subtle Gravitational Redshifts in clusters of galaxies. However, current models all neglect a Transverse Doppler redshift of similar magnitude, and some models are not self-consistent. An equilibrium model would fix the Gravitational and Transverse Doppler velocity shifts to be about 6\\sigma^2/c and 3\\sigma^2/2c in order to fit the observed velocity dispersion \\sigma self-consistently. This result is from the Virial Theorem for a spherical isotropic cluster, and is insensitive to the theory of gravity. In any case, a gravitational redshift signal cannot directly distinguish between the Einsteinian and f(R) gravity theories, because the mass of the cluster dark halo must be treated as an unknown fitting parameter, whose value must vary according to the theory adopted, otherwise the system would be in equilibrium in one gravity theory and out of equilibrium in another.

  15. A preliminary investigation of bird classification by Doppler radar

    Science.gov (United States)

    Martinson, L. W.

    1973-01-01

    A preliminary study of the application of Doppler radar to the classification of birds is reported. The desirability for improvements in bird classification stems primarily from the hazards they present to jet aircraft in flight and in the vicinity of airports. A secondary need exists in the study of bird migration. The wing body and tail motion of a bird in flight reflect signals which, when analyzed properly present a signature of wing beat pattern which is unique for each bird species. Although the results of this investigation did not validate the feasibility of classifying bird species, they do indicate that a more thorough investigation is warranted. Certain gross characteristics such as wing beat rates, multiple bird patterns, and bird maneuverability, were indicated clearly in the results. Large birds with slow wing beat rates appear to be the most optimum subject for further study with the X-band Doppler radar used in this investigation.

  16. Multipoint photonic doppler velocimetry using optical lens elements

    Science.gov (United States)

    Frogget, Brent Copely; Romero, Vincent Todd

    2014-04-29

    A probe including a fisheye lens is disclosed to measure the velocity distribution of a moving surface along many lines of sight. Laser light, directed to the surface and then reflected back from the surface, is Doppler shifted by the moving surface, collected into fisheye lens, and then directed to detection equipment through optic fibers. The received light is mixed with reference laser light and using photonic Doppler velocimetry, a continuous time record of the surface movement is obtained. An array of single-mode optical fibers provides an optic signal to an index-matching lens and eventually to a fisheye lens. The fiber array flat polished and coupled to the index-matching lens using index-matching gel. Numerous fibers in a fiber array project numerous rays through the fisheye lens which in turn project many measurement points at numerous different locations to establish surface coverage over a hemispherical shape with very little crosstalk.

  17. Photonic Doppler velocimetry lens array probe incorporating stereo imaging

    Energy Technology Data Exchange (ETDEWEB)

    Malone, Robert M.; Kaufman, Morris I.

    2015-09-01

    A probe including a multiple lens array is disclosed to measure velocity distribution of a moving surface along many lines of sight. Laser light, directed to the moving surface is reflected back from the surface and is Doppler shifted, collected into the array, and then directed to detection equipment through optic fibers. The received light is mixed with reference laser light and using photonic Doppler velocimetry, a continuous time record of the surface movement is obtained. An array of single-mode optical fibers provides an optic signal to the multiple lens array. Numerous fibers in a fiber array project numerous rays to establish many measurement points at numerous different locations. One or more lens groups may be replaced with imaging lenses so a stereo image of the moving surface can be recorded. Imaging a portion of the surface during initial travel can determine whether the surface is breaking up.

  18. Absorption and metabolism of volatile fatty acids by rumen and omasum Absorção e metabolismo de ácidos graxos voláteis pelo rúmen e omaso

    Directory of Open Access Journals (Sweden)

    João Luiz Pratti Daniel

    2012-02-01

    Full Text Available Volatile fatty acids (VFA absorption and metabolic capacity of rumen and omasum were compared, in vitro. Fragments of rumen wall and omasum laminae were taken from eight adult crossbred bovines. An isolated fragment of the mucosa was fitted in a tissue diffusion chamber. Valeric acid and CrEDTA were added to ruminal fluid and placed on the mucosal side and buffer solution was placed on the serosal side. Fractional absorption rates were measured by exponential VFA:Cr ratio decay over time. Metabolism rate was determined as the difference between VFA absorbed and VFA which appeared on the serosal side over time. Mitotic index was higher in omasum (0.52% than in rumen epithelium (0.28%. VFA fractional absorption rate was higher in omasum (4.6%/h.cm² than in rumen (0.4%/h.cm². Acetate, propionate, butyrate, and valerate showed similar fractional absorption rates in both fragments. Percentage of metabolized acetate and propionate was lower than butyrate and valerate in both stomach compartments. In the rumen, individual VFA metabolism rates were similar (mean of 7.7 , but in the omasum, valerate (90.0 was more metabolized than butyrate (59.6 propionate (69.8 and acetate (51.7 . Correlation between VFA metabolism and mitotic index was positive in the rumen and in the omasum. In conclusion, VFA metabolism and absorption potential per surface of the omasum is higher than that of the rumen. Variations on rumen and omasum absorption capacities occur in the same way, and there are indications that factors capable of stimulating rumen wall proliferation are similarly capable of stimulating omasum walls.A capacidade de absorção e metabolismo de ácidos graxos voláteis (AGV pelo rúmen e omaso foi comparada, in vitro. Fragmentos da parede do rúmen e das lâminas do omaso foram coletados de oito bovinos mestiços adultos. Um fragmento isolado da mucosa foi colocado em uma câmara de difusão tecidual. Ácido valérico e CrEDTA foram adicionados ao fluido ruminal e colocados no compartimento da câmara voltados para a mucosa e uma solução tampão foi colocada no compartimento voltado para a serosa. As taxas fracionais de absorção foram medidas pela queda exponencial da relação VFA:Cr ao longo do tempo. A taxa de metabolismo foi determinada pela diferença entre a quantidade de AGV absorvida e a detectada no compartimento serosal da câmara. O índice mitótico foi mais alto no epitélio do omaso (0.52% do que no do rúmen (0.28%, bem como a taxa fracional de absorção, 4.6%/h.cm² e 0.4%/h.cm², respectivamente. Acetato, propionato, butirato e valerato tiveram taxas fracionais de absorções similares em ambos os compartimentos. As porcentagens do acetato e do propionato metabolizados foram mais baixas do que a do butirato e valerato em ambos os compartimentos. No rúmen, a taxa metabólica individual dos AGV foi similar (média de 7.7 mas, no omaso, o valerato (90.0 foi mais metabolizado do que o butirato (59.6 propionato (69.8 e acetato (51.7 . A correlação entre o metabolismo de AGV e o índice mitótico foi positiva no rúmen e no omaso. Concluiu-se que o potencial de metabolismo e de absorção de AGV por unidade de área do omaso é mais alto do que o do rúmen. A variação da capacidade de absorção do rúmen e do omaso ocorre na mesma direção e existem indícios de que os fatores capazes de estimular a proliferação da parede do rúmen são também capazes de estimular a parede do omaso.

  19. Analytical theory of Doppler reflectometry in slab plasma model

    OpenAIRE

    Gusakov, Evgeniy; Surkov, Alexander

    2004-01-01

    Doppler reflectometry is considered in slab plasma model in the frameworks of analytical theory. The diagnostics locality is analyzed for both regimes: linear and nonlinear in turbulence amplitude. The toroidal antenna focusing of probing beam to the cut-off is proposed and discussed as a method to increase diagnostics spatial resolution. It is shown that even in the case of nonlinear regime of multiple scattering, the diagnostics can be used for an estimation (with certain ...

  20. Air tracer experiment around Mt. Tsukuba by two doppler radars

    Energy Technology Data Exchange (ETDEWEB)

    Kurita, S.; Satomura, T.; Yoshikawa, T.

    1986-01-01

    A remote sensing technique of pollutant diffusion in the atmosphere was studies for a real time monitoring system in a wide area. The first experiment was carried out around Mt. Tsukuba on 25-26 October 1983, using a system of two Doppler radars and radar reflective materials (Chaff) for a trace of air pollutants. One of the two radars is the C-band (5.3 GHz) meteorological Doppler radar fixed at the Meteorological Research Institute (MRI). The other, an X-band (10 GHz) meteorological Doppler radar, was set near Noda city, about 30 km from MRI. Observation ranges of the radars were selected to be 64 km, and the obtained data were processed by computer and stored on magnetic tapes. During this project, five runs were carried out. In each run, 7-10 packs of chaff were scattered from an airplane on a line at about 1000m height with about 5 km spacing between them. Main results obtained by this experiment are as follows: (a) Radar echo of chaff could be tracked for about 1-2 h and 20-100 km; (b) Doppler velocity data were effective in avoiding interferences of ground clutter, despite the low elevation of the radar antenna so that the chaff was superimposed on the ground clutter; (c) effects of the mountain on wind field were found from horizontal distributions of echo, and the wind profile was visualized by vertical cross-section; and (d) this system has advantages, compared with conventional experiments, because 3-dimensional distributions of air pollutants, wind velocities and diffusivities over complex terrain are analyzed in detail.

  1. Preoperative color Doppler assessment in planning of gluteal perforator flaps.

    Science.gov (United States)

    Isken, Tonguc; Alagoz, M Sahin; Onyedi, Murat; Izmirli, Hakki; Isil, Eda; Yurtseven, Nagehan

    2009-02-01

    Gluteal artery perforator flaps have gained popularity due to reliability, preservation of the muscle, versatility in flap design without restricting other flap options, and low donor-site morbidity in ambulatory patients and possibility of enabling future reconstruction in paraplegic patients. But the inconstant anatomy of the vascular plexus around the gluteal muscle makes it hard to predict how many perforators are present, what their volume of blood flow and size are, where they exit the overlying fascia, and what their course through the muscle will be. Without any prior investigations, the reconstructive surgeon could be surprised intraoperatively by previous surgical damage, scar formation, or anatomic variants.For these reasons, to confirm the presence and the location of gluteal perforators preoperatively we have used color Doppler ultrasonography. With the help of the color Doppler ultrasonography 26 patients, 21 men and 5 women, were operated between the years 2002 and 2007. The mean age of patients was 47.7 (age range: 7-77 years). All perforator vessels were marked preoperatively around the defect locations. The perforator based flap that will allow primary closure of the donor site and the defect without tension was planned choosing the perforator that showed the largest flow in color Doppler ultrasonography proximally. Perforators were found in the sites identified with color Doppler ultrasonography in all other flaps. In our study, 94.4% flap viability was ensured in 36 perforator-based gluteal area flaps. Mean flap elevation time was 31.9 minutes. We found that locating the perforators preoperatively helps to shorten the operation time without compromising a reliable viability of the perforator flaps, thus enabling the surgeon easier treatment of pressure sores. PMID:19158526

  2. Doppler Radar for Heartbeat Rate and Heart Rate Variability Extraction

    OpenAIRE

    Obeid, Dany; Sadek, Sawsan; Zaharia, Gheorghe; El Zein, Ghaïs

    2011-01-01

    This paper presents a Doppler radar system used to detect the heartbeat signal from a d√istance of one meter. The proposed system is based on using a vector network analyzer and two antennas. Measurements are performed at 16 GHz for different power levels between 0 and -25 dBm. Both heartbeat rate and heart rate variability are extracted and compared to a simultaneous ECG signal.

  3. Evaluation of turbulent dissipation rate retrievals from Doppler Cloud Radar

    OpenAIRE

    Shupe, M. D.; Brooks, I.M.; Canut, G.

    2012-01-01

    Turbulent dissipation rate retrievals from cloud radar Doppler velocity measurements are evaluated using independent, in situ observations in Arctic stratocumulus clouds. In situ validation data sets of dissipation rate are derived using sonic anemometer measurements from a tethered balloon and high frequency pressure variation observations from a research aircraft, both flown in proximity to stationary, ground-based radars. Modest biases are found among the data sets in particularly low- or ...

  4. Single data set detection for multistatic doppler radar

    OpenAIRE

    Shtarkalev, Bogomil Iliev

    2015-01-01

    The aim of this thesis is to develop and analyse single data set (SDS) detection algorithms that can utilise the advantages of widely-spaced (statistical) multiple-input multiple-output (MIMO) radar to increase their accuracy and performance. The algorithms make use of the observations obtained from multiple space-time adaptive processing (STAP) receivers and focus on covariance estimation and inversion to perform target detection. One of the main interferers for a Doppler rada...

  5. Evaluation of turbulent dissipation rate retrievals from Doppler cloud radar

    OpenAIRE

    Shupe, M. D.; Brooks, I.M.; Canut, G.

    2012-01-01

    Turbulent dissipation rate retrievals from cloud radar Doppler velocity measurements are evaluated using independent, in situ observations in Arctic stratocumulus clouds. In situ validation data sets of dissipation rate are derived using sonic anemometer measurements from a tethered balloon and high frequency pressure variation observations from a research aircraft, both flown in proximity to stationary, ground-based radars. Modest biases are found among the data sets in ...

  6. Reactive Collision Avoidance for Unmanned Aerial Vehicles using Doppler Radar

    OpenAIRE

    Viquerat, Andrew; Blackhall, Lachlan; Reid, Alistair; Sukkarieh, Salah; Brooker, Graham

    2007-01-01

    Research into reactive collision avoidance for unmanned aerial vehicles has been conducted on unmanned terrestrial and mini aerial vehicles utilising active Doppler radar obstacle detection sensors. Flight tests conducted by flying a mini UAV at an obstacle have confirmed that a simple reactive collision avoidance algorithm enables aerial vehicles to autonomously avoid obstacles. This builds upon simulation work and results obtained using a terrestrial vehicle that had already confirmed that ...

  7. Ultrasonography and color Doppler in juvenile idiopathic arthritis

    DEFF Research Database (Denmark)

    Laurell, Louise; Court-Payen, Michel; Nielsen, Susan; Zak, Marek; Boesen, Mikael; Fasth, Anders

    2011-01-01

    Background The ankle region is frequently involved in juvenile idiopathic arthritis (JIA) but difficult to examine clinically due to its anatomical complexity. The aim of the study was to evaluate the role of ultrasonography (US) of the ankle and midfoot (ankle region) in JIA. Doppler-US detected synovial hypertrophy, effusion and hyperemia and US was used for guidance of steroid injection and to assess treatment efficacy. Methods Forty swollen ankles regions were studied in 30 patients (median ...

  8. Analytical theory of Doppler reflectometry in slab plasma model

    CERN Document Server

    Gusakov, E; Gusakov, Evgeniy; Surkov, Alexander

    2004-01-01

    Doppler reflectometry is considered in slab plasma model in the frameworks of analytical theory. The diagnostics locality is analyzed for both regimes: linear and nonlinear in turbulence amplitude. The toroidal antenna focusing of probing beam to the cut-off is proposed and discussed as a method to increase diagnostics spatial resolution. It is shown that even in the case of nonlinear regime of multiple scattering, the diagnostics can be used for an estimation (with certain accuracy) of plasma poloidal rotation profile.

  9. Choroid metastasis of papillary thyroid carcinoma. Color doppler ultrasound study

    International Nuclear Information System (INIS)

    The most common causes of intraocular metastases are breast and lung cancers, although many other neoplasms can metastasize to the eye. Most of the metastases are located in the posterior pole and the choroid is more often involved than the retina. We present a case of a choroidal metastasis from a papillary carcinoma of the thyroid, associated with a massive subretinal hemorrhage. Findings with color Doppler ultrasound are emphasized. (Author) 9 refs

  10. Prediction of cerebrovascular reserve by the MRI and doppler ultrasonography

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hui Joong; Kim, Yong Sun [Kyungpook National University Hospital, Daegu (Korea, Republic of)

    2005-07-15

    We investigated acute stroke patterns on diffusion weighted images and with doppler ultrasonography studies of ICA and MCA steno-occlusive diseases in order to predict the cerbrovascular reserve (CVR), as was measured by acetazolamide (ACZ)-challenged Tc-99m ECD brain perfusion SPECT. A retrospective analysis was performed of 76 patients who underwent MRI/MRA, ACZ-challenged Tc-99m ECD brain perfusion SPECT, and carotid and vertebral artery Doppler sonography. After dividing these patients into four groups-MCA and ICA ateno-occlusions, we analyzed the relationship between the CVR and topologic MR patterns and the flow volume, as was measured by Doppler sonography. The CVRs were preserved in 26 of 76 patients. The CVRs were impaired in those cases of occlusion that were detected on MRA and also by the pattern of the territorial involvement on the diffusion weighted image ({rho} < 0.05, x{sup 2} test). Yet in cases of preserved CVRs, the flow volume of the contralateral ICA, the anterior circulation, and the total cerebral flow volume were increased, as was checked by Doppler sonography ({rho} < 0.05, t-test). As calculated by logistic regression analysis, the accuracy for predicting the preserved CVR by using the statistically significant variables was 78%. We believe that the MRI-SPECT correlation study was helpful for understanding the hemodynamics and topographic patterns of ischemia in patients with ICA and MCA steno-occlusive disease, and that the flow volume measurement, which was done by using duplex US, was useful for predicting the CVR.

  11. Spread-Spectrum Carrier Estimation With Unknown Doppler Shift

    Science.gov (United States)

    DeLeon, Phillip L.; Scaife, Bradley J.

    1998-01-01

    We present a method for the frequency estimation of a BPSK modulated, spread-spectrum carrier with unknown Doppler shift. The approach relies on a classic periodogram in conjunction with a spectral matched filter. Simulation results indicate accurate carrier estimation with processing gains near 40. A DSP-based prototype has been implemented for real-time carrier estimation for use in New Mexico State University's proposal for NASA's Demand Assignment Multiple Access service.

  12. Detecting a gravitational-radiation background using spacecraft Doppler tracking

    International Nuclear Information System (INIS)

    The sensitivity of NASA's Deep Space Network spacecraft tracking system to an isotropic cosmological background of gravitational radiation is analyzed. It is found that by using the autocovariance function of the Doppler record in the so-called ''three-way'' tracking mode to dig into the noise it is possible to put significant limits on this background with current and future planned deep-space missions

  13. Value of intraplacental villous artery Doppler measurements in severe preeclampsia.

    OpenAIRE

    Lacin S; Demir N; Koyuncu F; Goktay Y

    1996-01-01

    Blood flow velocity waveforms were recorded by color Doppler ultrasound from intraplacental villous and umbilical arteries in 20 normal and 23 severe preeclamptic pregnancies. The results of the resistance index measurements in intraplacental villous arteries were 0.51 +/- 0.037 and 0.55 +/- 0.052 in healthy controls and preeclamptics respectively, which was not significantly different. Resistance indices showed a decrease through the umbilical cord from fetus to placenta in bot...

  14. Sub-Doppler modulation spectroscopy of potassium for laser stabilization

    CERN Document Server

    Mudarikwa, L; Goldwin, J

    2011-01-01

    We study modulation spectroscopy of the potassium D2 transitions at 766.7 nm. Heterodyne detection of pump-probe spectroscopy yields sub-Doppler frequency discriminants suitable for stabilizing lasers in experiments with cold atoms. Comparisons are made between spectra obtained by direct modulation of the probe beam, and those using modulation transfer from the pump via nonlinear mixing. Finally, suggestions are made for further optimization of the signals.

  15. Identification and Minimization of Errors in Doppler Global Velocimetry Measurements

    Science.gov (United States)

    Meyers, James F.; Lee, Joseph W.

    2000-01-01

    A systematic laboratory investigation was conducted to identify potential measurement error sources in Doppler Global Velocimetry technology. Once identified, methods were developed to eliminate or at least minimize the effects of these errors. The areas considered included the Iodine vapor cell, optical alignment, scattered light characteristics, noise sources, and the laser. Upon completion the demonstrated measurement uncertainty was reduced to 0.5 m/sec.

  16. A Fisheye Lens as a Photonic Doppler Velocimetry Probe

    Energy Technology Data Exchange (ETDEWEB)

    Frogget, B. C.

    2012-08-16

    These presentation visuals report an instrument that, by use of a fish-eye lens, generates a beat signal using fiber mixing of unshifted light with Doppler-shifted light and measures the beat frequency. Ray trace diagrams are shown to illustrate advantages and disadvantages. The authors find their instrument has a long tracking distance, and large angle coverage. Index matching eases assembly, reduces return loss and flattens the field.

  17. Knowledge Exploitation for Human Micro-Doppler Classification

    OpenAIRE

    Karabacak, Cesur; Gurbuz, Sevgi Z.; Gurbuz, Ali C.; Guldogan, Mehmet B.; Hendeby, Gustaf; Gustafsson, Fredrik

    2015-01-01

    Micro-Doppler radar signatures have great potential for classifying pedestrians and animals, as well as their motion pattern, in a variety of surveillance applications. Due to the many degrees of freedom involved, real data need to be complemented with accurate simulated radar data to be able to successfully design and test radar signal processing algorithms. In many cases, the ability to collect real data is limited by monetary and practical considerations, whereas in a simulated environment...

  18. MRI and colour-Doppler in sclerosing mesenteritis

    International Nuclear Information System (INIS)

    We present a case of sclerosing mesenteritis with fibrofatty thickening of the mesentery. Ultrasonography showed an echodense mesenteric mass and colour-Doppler displayed patent mesenteric vessels with high vascular resistance. On CT, low-density areas suggesting fatty infiltration were seen in the mesentery. MRI showed low-signal areas suggesting a fibrous component of the mesenteric mass and GRASS imaging confirmed normal patency of the mesenteric vessels. (orig.)

  19. Sub-Doppler modulation spectroscopy of potassium for laser stabilization

    OpenAIRE

    Mudarikwa, L.; Pahwa, K.; Goldwin, J.

    2011-01-01

    We study modulation spectroscopy of the potassium D2 transitions at 766.7 nm. The vapour pressure, controlled by heating a commercial reference cell, is optimized using conventional saturated absorption spectroscopy. Subsequent heterodyne detection yields sub-Doppler frequency discriminants suitable for stabilizing lasers in experiments with cold atoms. Comparisons are made between spectra obtained by direct modulation of the probe beam, and those using modulation transfer f...

  20. Doppler effect and frequency-shift in optics

    CERN Document Server

    Tiwari, S C

    2004-01-01

    A critical review of frequency-shift phenomena a la Doppler effect is presented. The importance of Fermi's theory of 1932 is pointed out, and it is argued that there exists a gap in our understanding of this phenomena at a fundamental level. Alternative mechanism in terms of photon number oscillations is suggested for polarization changing experiments. The physical reality of single photon is revisited, and a possible experimental scheme to test the alternative mechanism is suggested.