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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. 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 ...

  3. Welcome to the TEI’10 Proceedings

    DEFF Research Database (Denmark)

    Pederson, Thomas; Shaer, Orit; Wakkary, Ron

    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 environme...

  4. 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...

  5. 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.

  6. 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.

  7. 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±12? 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.

  8. 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.

  9. 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.

  10. Circle K Cycles: uma diáspora à brasileira na obra de Karen Tei Yamashita

    Directory of Open Access Journals (Sweden)

    Cláudio Roberto Vieira Braga

    2009-11-01

    Full Text Available The intent of this work is to offer a discussion of diaspora, outlined by its consensual features found in the studies of theorists William Safran (1991, Khachig Tölölyan (1996, James Clifford (1994, Robin Cohen (1995, 1999, and Paul Gilroy (1999. Here we emphasize the need of a more accurate use of the term diaspora. Simultaneously, we analyze the fictional representation of a Brazilian diasporic formation in Circle K Cycles. In this book, by Japanese-American Karen Tei Yamashita, we identify and problematize diaspora through the means of some characteristics, such as the dispersion and its reasons, the relationship with the homeland, conflicts in the hostland, the myth of return and the ethnic group consciousness.

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. [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

  17. VALORACIÓN DE PREFERENCIAS SOCIALES POR UNA ALTERNATIVA DE REGENERACIÓN DEL LITORAL FRENTE A UN PUERTO DEPORTIVO EN TEIS (VIGO

    Directory of Open Access Journals (Sweden)

    ROI DUR\\u00C1N MEDRA\\u00D1O

    2009-01-01

    disposición al pago (DAP o variación compensatoria de los residentes por un plan de regeneración del litoral frente al proyecto de ampliación de un puerto deportivo en Punta Lagoa en Teis (Vigo. Para el análisis de las respuestas se empleó un modelo paramétrico y uno no paramétrico, que no precisa asumir ninguna forma funcional de la distribución de la disposición al pago. Las estimaciones obtenidas muestran una DAP de 48 /hogar y de 34 /hogar, respectivamente. De estos resultados se deriva que el plan de regeneración del litoral llevaría consigo una ganancia de bienestar social respecto de la ampliación del puerto deportivo o, lo que es lo mismo, que existe un coste social asociado a este último. Al mismo tiempo, a la luz de los resultados y ante las ventajas que ofrece el estimador Turnbull, se recomienda un mayor empleo de los métodos no paramétricos para obtener estimadores a partir de datos de valoración contingente.

  18. 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.

  19. 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.

  20. 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...

  1. 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...

  2. 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...

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

    OpenAIRE

    Jens E. Wilhjelm; Pedersen, P. C.

    2010-01-01

    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 ...

  4. 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

  5. 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

  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 ?eV, even when the ultra-high energy resolution of ?E?0.03 ?eV is attained. (author)

  7. 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.

  8. 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 a...

  9. 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.

  10. 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...

  11. 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.

  12. 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 ?m. 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

  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. Neutrino induced Doppler broadening

    International Nuclear Information System (INIS)

    When a nucleus undergoes beta decay via the electron capture reaction, it emits an electron neutrino. The neutrino emission gives a small recoil to the atom, which can be experimentally observed as a Doppler broadening on subsequently emitted gamma rays. Using the two-axis flat-crystal spectrometer GAMS4 and the electron capture reaction in 152Eu, the motion of atoms having an excess kinetic energy of 3 eV in the solid state was studied. It is shown how the motion of the atom during the first hundreds of femtoseconds can be reconstructed. The relevance of this knowledge for a new neutrino helicity experiment is discussed

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

    DEFF Research Database (Denmark)

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

    1995-01-01

    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. This approach requires a priori knowledge of the envelope of the received sweep from a point scatterer

  16. 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.

  17. 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

  18. Thermographic laser Doppler velocimetry.

    Science.gov (United States)

    Ojo, Anthony O; Fond, Benoit; Van Wachem, Berend G M; Heyes, Andrew L; Beyrau, Frank

    2015-10-15

    We propose a point measurement technique for simultaneous gas temperature and velocity measurement based on thermographic phosphor particles dispersed in the fluid. The flow velocity is determined from the frequency of light scattered by BaMgAl10O17:Eu2+ phosphor particles traversing the fringes like in conventional laser Doppler velocimetry. Flow temperatures are derived using a two-color ratio method applied to the phosphorescence from the same particles. This combined diagnostic technique is demonstrated with a temperature precision of 4%-10% in a heated air jet during steady operation for flow temperatures up to 624 K. The technique provides correlated vector-scalar data at high spatial and temporal resolution. PMID:26469613

  19. 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.

  20. 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.

  1. 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)

  2. 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...

  3. 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

  4. 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.

  5. 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.

  6. 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.)

  7. 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.

  8. 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.

  9. 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.

  10. Doppler tomography in fusion plasmas and astrophysics

    CERN Document Server

    Salewski, Mirko; Heidbrink, Bill; Jacobsen, Asger Schou; Korsholm, Soren Bang; Leipold, Frank; Madsen, Jens; Moseev, Dmitry; Nielsen, Stefan Kragh; Rasmussen, Jesper; Stagner, Luke; Steeghs, Danny; Stejner, Morten; Tardini, Giovani; Weiland, Markus

    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-alpha (FIDA) spectroscopy measurements in magnetically confined plasma, the D-alpha-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 lead 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 ...

  11. 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.

  12. 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.

  13. 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.

  14. 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)

  15. Doppler broadening of cross sections

    International Nuclear Information System (INIS)

    Expressions for temperature dependent cross-sections in terms of resonance parameters are obtained, involving generalisations of the conventional Doppler functions, ? and ?. Descriptions of Fortran sub-routines, which calculate broadened cross-sections in accordance with the derived formulae, are included. (author)

  16. 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.

  17. 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 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 emi...

  18. 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

  19. 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.)

  20. 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.

  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 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.

  3. 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.

  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. 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

  6. Carotid Artery Doppler Assessment In Patients Accussed Of Strokes

    OpenAIRE

    H Mazaher; S. Sharif Kashani

    2005-01-01

    Carotid Doppler ultrasound assessment mostly indicated in patients accussed of TIAs or in younger patients with nonpersistant neurologic deficits. This assessment should be consisted of gray scale sonography, color Doppler Sonography, spectral Doppler sonography and power Doppler sonography. By gray scale sonography atherosclerotic plaques assessed from the point of Homogenousity, degree of echogenicity, surface regularity, calcification, length, Thichkness and sites of involvement. In color ...

  7. Noncoherent Doppler tracking: first flight results

    Science.gov (United States)

    DeBoy, Christopher C.; Robert Jensen, J.; Asher, Mark S.

    2005-01-01

    Noncoherent Doppler tracking has been devised as a means to achieve highly accurate, two-way Doppler measurements with a simple, transceiver-based communications system. This technique has been flown as an experiment on the Thermosphere, Ionosphere, Mesosphere, Energetics and Dynamics (TIMED) spacecraft, (launched 7 December 2001), as the operational technique for Doppler tracking on CONTOUR, and is baselined on several future deep space missions at JHU/APL. This paper reports on initial results from a series of successful tests of this technique between the TIMED spacecraft and NASA ground stations in the Deep Space Network. It also examines the advantages that noncoherent Doppler tracking and a transceiver-based system may offer to small satellite systems, including reduced cost, mass, and power.

  8. 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...

  9. 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)

  10. 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...

  11. 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)

  12. 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.

  13. 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 ...

  14. 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

  15. 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

  16. 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.

  17. 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

  18. 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.

  19. 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

  20. 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

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. 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

  10. 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...

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. 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....

  16. 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...

  17. 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...

  18. 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)

  19. 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.

  20. 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)

  1. 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

  2. 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''

  3. 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

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. [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

  9. 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

  10. 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....

  11. 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.

  12. 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.

  13. Intracoronary Doppler: Clinical Application And Future Directions

    Science.gov (United States)

    Whitlow, Patrick L.; Raymond, Russell E.; Tuzcu, E. Murat

    1989-08-01

    Because coronary arteriography may underestimate the severity of coronary artery disease, other methods to assess the physiologic significance of a coronary lesion have been sought. Experimental data have confirmed that the ratio of peak flow to resting flow, coronary vasodilator reserve (CVDR), is a quantitative measure of the functional significance of a coronary a stenosis. A 20 MHz pulsed Doppler catheter with a 1 mm outer diameter and an innerlumen for guidewire placement was developed in 1985 and has been used for clinical measurement of CVDR. The technique appears safe, and reliable signals can be obtained in the vast majority of patients studied. Limitations of the technique include possible changes in vessel diameter with delivery of a vasodilator stimulus, possible elevation of baseline flow above normal resting values which would diminish the CVDR, and inability to measure absolute coronary flow. These limitations could be overcome by the development of an intravascular Echo-Doppler device in the future.

  14. 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.

  15. 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

  16. 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.)

  17. 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.)

  18. 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...

  19. 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...

  20. Coherent Detection in Laser Doppler Velocimeters

    DEFF Research Database (Denmark)

    Hanson, Steen Grüner

    1974-01-01

    The possibility of heterodyning between electromagnetic waves scattered by particles separated in space is explained from a classical point of view and from a quantum mechanical point of view. The last description being carried out using only the Heisenberg uncertainty principle and a rather coarse, but intelligible particle picture of electromagnetic waves. The analysis is carried out with special emphasis on the heterodyning process in the laser Doppler velocimeter (LDV) because the main purpo...

  1. 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...

  2. 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 ...

  3. 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 (?-DS) based radar Automatic Target Recognition (ATR) with additional contributions to general radar ATR methodology. The ?-DS based part of the research contributes to three distinct areas: time domain classification; frequency domain classification; and multiperspective ?-DS classification that includes the development of a theory for the multistatic ?-DS. The contribution to general radar ATR is the proposal of a ...

  4. The Doppler peaks from a generic defect

    OpenAIRE

    Magueijo, Joao

    1996-01-01

    We investigate which of the exotic Doppler peak features found for textures and cosmic strings are generic novelties pertaining to defects. We find that the ``out of phase'' texture signature is an accident. Generic defects, when they generate a secondary peak structure similar to inflation, apply to it an additive shift. It is not necessary for this shift to be ``out of phase''. We also show which factors are responsible for the absence of secondary oscillations found for c...

  5. 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...

  6. 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...

  7. 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...

  8. 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.

  9. 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.

  10. 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

  11. Optimal processing of Doppler signals in OCT

    Science.gov (United States)

    Walther, Julia; Kirsten, Lars; Koch, Edmund

    2015-07-01

    Besides structural imaging, OCT can be used to estimate axial velocities of the sample resolved in depth by Doppler processing. In Fourier domain OCT (FD-OCT), this is accomplished by measuring the phase difference (i.e. phase shift) between timely separated A-scans at the same depth. In most cases, these data are disturbed by noise caused by intrinsic noise of the OCT system, specified by the SNR, and decorrelation noise caused by the transversal movement of the optical beam relative to the sample. Since the first use of Doppler methods in OCT, many methods to reduce the phase shift noise by averaging have been presented. While all these methods use a fixed set of consecutive A-scans, the best method, exhibiting no bias and having the smallest standard deviation, was questionable. Recently, Doppler processing methods depending on the mentioned noise sources and delivering the most likely phase shift and thereby axial velocity became available. The relation of these methods to previously known methods like the Kasai estimator, maximum likelihood estimator (MLE) and joint spectral and time domain OCT (jSTdOCT) will be discussed.

  12. 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...

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. 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...

  18. Colour Doppler imaging in the demonstration of an orbital varix.

    OpenAIRE

    Lieb, W E; Merton, D. A.; Shields, J. A.; Cohen, S. M.; Mitchell, D. D.; Goldberg, B. B

    1990-01-01

    Colour Doppler imaging (CDI) is a recent development in ultrasonography. It allows simultaneous two-dimensional structural imaging and Doppler evaluation of blood flow. Quantitative information on flow velocity is obtained by pulsed Doppler spectral analysis, the colour information being used to choose the vessel of interest. Using this technique the authors examined a patient with an orbital varix previously diagnosed by clinical findings and computed tomography. Dynamic evaluation with real...

  19. 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 FF...

  20. 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.

  1. 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...

  2. 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...

  3. 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....

  4. 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...

  5. 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...

  6. 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...

  7. 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,...

  8. 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)

  9. 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.

  10. 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.

  11. 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.

  12. [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

  13. Tecnología Doppler y movimientos respiratorios fetales

    Scientific Electronic Library Online (English)

    Marisol, García Noguera de Yegüez; Efraín, Inaudy Bolívar.

    2008-03-01

    Full Text Available La tecnología ultrasónica Doppler ha resultado ser una herramienta fundamental para la evaluación de la fisiología fetal, dando información importante sobre el estado hemodinámico fetal. Teniendo en cuenta que no sólo el desarrollo y crecimiento normal del feto y su bienestar intraútero depende de u [...] na adecuada función de la circulación útero placentaria y feto placentaria, sino de otras estructuras orgánicas, es por lo que este método abre una línea de investigación dentro del campo de la fisiología fetal. El propósito de esta revisión es exponer de forma clara los conceptos relacionados con el desarrollo y fisiología de la respiración fetal abordando técnicas no invasivas de evaluación del bienestar fetal como la tecnología Doppler color y con la cual es posible estudiar el movimiento del líquido amniótico a través del flujo transnasal. Es pues factible analizar, cualitativa y cuantitativamente, las ondas de velocidad de dicho flujo a través del análisis espectral de los movimientos respiratorios fetales, relacionados íntimamente con la máxima producción de esteroides fetales responsables de la madurez pulmonar fetal. Se presentan las diferentes metodologías y recursos diagnósticos aplicados en los últimos años en la evaluación de los movimientos respiratorios en el bienestar fetal y su importancia. Se realiza una breve descripción de la fisiología y desarrollo del sistema respiratorio fetal. Abstract in english Doppler ultrasound technology has been the main tool for monitoring fetal physiology, giving important information about fetal haemodinamic status. We are aware that normal fetal growing and development and its intra womb wellbeing depends on an accurate uterus - placental blood circulation as fetal [...] - placental, but with other organic structures, and this is the reason why this method opens a wide investigation line in the field of fetal physiology. Our purpose is to expose clearly the concepts involved in fetal breath development and physiology with non invasive techniques of fetal wellbeing such as color Doppler technology, by witch is possible to study the movement of amniotic flux through transnasal flux, as we can evaluate qualitatively and quantitatively by the velo-city waves of such flux through the spectral analysis of fetal breath movements, closely related to the higher production of fetal steroids responsible of fetal lung maturation. Different methodologies are presented and diagnostic resources applied in this last years over the breath movements and its relation to fetal wellbeing and its importance. We also do a description of fetal breath system development and physiology.

  14. 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.

  15. Check list Doppler and duplex sonography. 4. rev. ed.; Checkliste Doppler- und Duplexsonografie

    Energy Technology Data Exchange (ETDEWEB)

    Kopp, Helmut [MED-Facharztzentrum, Mainz (Germany). Praxis fuer Gefaessmedizin; Ludwig, Malte [Benedictus Krankenhaus Tutzing (Germany). Gefaesszentrum

    2012-11-01

    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.

  16. 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].

  17. 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.

  18. Comparison of Triature Doppler Velocimetry and VISAR

    International Nuclear Information System (INIS)

    Triature Photonic Doppler Velocimetry (TDV) is an adaptation of Photonic Doppler Velocimetry (PDV) that rejects common-mode data noise after splitting PDV three ways, with each signal 120o out of phase from each other. Testing has demonstrated that TDV also improves temporal resolution from the typical five nanoseconds of PDV to a subnanosecond range. This paper compares the temporal response of TDV with that of PDV and VISAR (velocity interferometer system for any reflector) in an experiment with a subnanosecond (?120-picosecond rise time) shock source. Laboratory tests were performed using a high-power laser on targets of copper and aluminum. A Buce Marshall fast VISAR with a single-point PDV and a prototype TDV were used. A special probe that combined PDV, TDV, and fast VISAR made simultaneous velocity measurements. Breakout velocities of 1.3 km/second on copper and 2.5 km/second on aluminum were observed, where TDV resolved rise times of ?200 ps. This resolution was better than that of a fast VISAR, which can achieve ?500 ps temporal resolution. Test methods and results are presented.

  19. Comparison of Triature Doppler Velocimetry and Visar

    International Nuclear Information System (INIS)

    Triature Photon Doppler Velocimetry (TDV) is an adaptation of Photonic Doppler Velocimetry (PDV) that rejects common-mode data noise after splitting PDV three ways, with each signal 1200 out of phase from each other. Testing has demonstrated that the TDV also improves temporal resolution from the typical five-nanoseconds of PDV to a subnanosecond range. This paper compares the temporal response of TDV with that of PDV and VISAR [velocity interferometer system for any reflector] in an experiment with a subnanosecond (?120-picosecond rise time) shock source. Laboratory tests were performed using a high-power laser on targets of copper and aluminum. A fast VISAR with a single-point PDV and a prototype TDV were used. A special probe that combined PDV, TDV, and fast VISAR made simultaneous velocity measurements. Breakout velocities of 1.3 km/second on copper and 2.5 km/second on aluminum were observed, where TDV resolved rise times of ?200 ps. This resolution was better than that of a fast VISAR, which can achieve ?500 ps temporal resolution. Test methods and results are presented.

  20. 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

  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. 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.

  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. "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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Coherent Detection in Laser Doppler Velocimeters

    DEFF Research Database (Denmark)

    Hanson, Steen Grüner

    1974-01-01

    The possibility of heterodyning between electromagnetic waves scattered by particles separated in space is explained from a classical point of view and from a quantum mechanical point of view. The last description being carried out using only the Heisenberg uncertainty principle and a rather coarse, but intelligible particle picture of electromagnetic waves. The analysis is carried out with special emphasis on the heterodyning process in the laser Doppler velocimeter (LDV) because the main purpose of this article is to provide a better understanding of this instrument. An aid for this purpose is the evaluation of a visual comprehensive interference pattern (Moiré pattern), which furthermore reveals some important features of the optical set-up.

  11. 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

  12. 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.

  13. 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.

  14. 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

  15. [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

  16. Interferometric millimeter wave and THz wave doppler radar

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    DEFF Research Database (Denmark)

    Hansen, Henrik; Affes, Sofiene

    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 good results.

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

    DEFF Research Database (Denmark)

    Hansen, Henrik; Affes, Sofiéne

    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 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 results

  19. 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...

  20. 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.

  1. 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.

  2. Almost Linear Complexity Methods for Delay-Doppler Channel Estimation

    OpenAIRE

    Fish, Alexander; Gurevich, Shamgar

    2013-01-01

    A fundamental task in wireless communication is channel estimation: Compute the channel parameters a signal undergoes while traveling from a transmitter to a receiver. In the case of delay-Doppler channel, i.e., a signal undergoes only delay and Doppler shifts, a widely used method to compute delay-Doppler parameters is the pseudo-random method. It uses a pseudo-random sequence of length N; and, in case of non-trivial relative velocity between transmitter and receiver, its c...

  3. 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...

  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. 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....

  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. 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.

  8. 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.

  9. 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...

  10. 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

  11. 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.

  12. 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.

  13. Folded-path doppler and the measurement of blood flow

    Science.gov (United States)

    Crane, H. Richard

    1999-09-01

    Everyone who has listened to a train go by while blowing its whistle has heard the Doppler frequency shift. The practical problem is finding the velocity of something moving at some distance that neither transmits nor receives.

  14. 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)

  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. 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.)

  17. 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.)

  18. 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 ...

  19. 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 de...

  20. 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...

  1. 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.

  2. Color Doppler Ultrasonography in Evaluation of the Postoperative Penis

    OpenAIRE

    M. Ghafouri

    2005-01-01

    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 penil...

  3. 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...

  4. DELAY-DOPPLER PERFORMANCE OF HYPERBOLIC FREQUENCY MODULATION WAVEFORMS

    OpenAIRE

    A.NAGAJYOTHI; K. RAJA RAJESWARI

    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...

  5. 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...

  6. 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...

  7. 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 ...

  8. 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...

  9. 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 ...

  10. 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...

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

    Science.gov (United States)

    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.

  12. 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)

  13. 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...

  14. 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.

  15. 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

  16. 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 ...

  17. 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

  18. 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...

  19. VW Hyi: optical spectroscopy and Doppler tomography

    CERN Document Server

    Smith, A J; Hynes, R I; Smith, Amanda J.; Haswell, Carole A.; Hynes, Robert I.

    2006-01-01

    We present high quality optical spectroscopy of the SU UMa-subtype dwarf nova, VW Hyi taken while the system was in quiescence. An S-wave is executed by the emission cores of the Hydrogen Balmer lines and by the emission lines of He I, Ca II, Fe II and He II. Using Doppler tomography we show it originates in the accretion stream-disc impact region. The He II emission is strongly phase-dependent, suggesting it originates exclusively within a hot cavity at the initial impact. We map the ionization structure of the stream-disc interaction region. One possible interpretation of this is that the Balmer hotspot lies downstream of the He II hotspot in the outer accretion disc, with the He I and Ca II hotspots at intermediate locations between the two. This suggests that Balmer emission is suppressed until material has cooled somewhat downstream of the impact site and is able to recombine. We favour a phase offset of 0.15+/-0.04 between the photometric ephemeris and inferior conjunction of the mass donor. The white d...

  20. 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 ...

  1. Transcranial duplex doppler ultrasonography in dogs with hydrocephalus / Ultrassonografia duplex Doppler transcraniana em cães com hidrocefalia

    Scientific Electronic Library Online (English)

    C.F., Carvalho; M.C., Chammas; J.P., Andrade Neto; C.D., Jimenez; S.A., Diniz; G.G., Cerri.

    2010-02-01

    Full Text Available Foi realizada a ultrassonografia duplex Doppler transcraniana em 32 cães, conscientes, que apresentavam ventriculomegalia previamente detectada ao exame modo-B, para obter as medidas dos ventrículos laterais e os parâmetros de resistência das artérias cerebrais antes e depois de 30 dias de tratament [...] o clínico. Os animais foram distribuídos em dois grupos: 1 - formado por cães que apresentaram remissão ou diminuição dos sinais clínicos após tratamento; 2 - por cães que apresentaram piora dos sinais neurológicos ou estabilidade do quadro clínico. Todos os dados foram dispostos em tabelas e submetidos ao teste t pareado e a modelos de regressão logística para avaliar a influência da redução do índice de resistividade (IR). Não foi observada influência das variáveis em modo-B. Após o tratamento, a média do IR foi significantemente menor para o grupo que apresentou melhora clínica; não houve diferença significativa da média de redução do IR para a mesma artéria quando comparados os lados direito e esquerdo. Concluiu-se que o duplex Doppler transcraniano é um métodos de avaliação hemodinâmica capaz de monitorar mais precisamente o tratamento da hidrocefalia em cães e verificar a resposta dos pacientes. Abstract in english Transcranial duplex Doppler ultrasound was performed in 32 conscious dogs presenting ventriculomegaly detected in B-mode, obtaining measures of lateral ventricles and resistance parameters of main cerebral arteries before and after 30 days of clinical treatment. The animals were distributed divided [...] in two groups: group 1, dogs that presented remission or decrease of the neurological signs of the disease after clinical therapy; and group 2, dogs that displayed worsening of the neurological signs or clinical stability. The data were all presented in tables and were submitted to paired t test and to logistic regression models to evaluate the influence of the RI reduction on both groups. There was no significant influence of the variables in the B-mode. After the treatment, the mean resistive index (RI) was significantly lower for the group that presented clinical improvement. There was no significant difference of the mean RI reduction for the same artery when the right and left sides were compared. It could be concluded that transcranial duplex Doppler ultrasound is a method of cerebral hemodynamic assessment able to monitor more precisely the treatment of hydrocephalus in dogs and verify the responses.

  2. Analysis of Radar Doppler Signature from Human Data

    Directory of Open Access Journals (Sweden)

    M. ANDRI?

    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.

  3. 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 $15.2^{+6.7}_{-7.6}~ M_{\\oplus}$.

  4. 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.

  5. 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.

  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. 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.

  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. 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

  10. 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.

  11. 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.

  12. 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.

  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

    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}.

  15. 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.

  16. 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

  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. Differentiation of abdominal lymphadenoptahy with power doppler sonography

    International Nuclear Information System (INIS)

    Purpose: Recent studies have reported high accuracy of power Doppler sonography (PDS) and color Doppler sonography (CDS) in the differentiation of benign and malignant peripheral superficial lymphadenopathy. This study was conducted to determine whether PDS can differentiate benign from malignant abdominal lymph nodes on the basis of defined vascular patterns. Materials and Methods: We retrospectively evaluated 88 color pictures of abdominal lymph nodes (39 benign lymph nodes, 24 malignant lymphomas, 25 lymph node metastasis) done in the power Doppler mode. The goal was to determine whether benign and malignant abdominal lymph nodes can be differentiated in power Doppler sonography on the basis of 9 defined vascular patterns. Results: Three vascular patterns showed a significantly (p < 0.05) higher appearance in malignant than in benign lymph nodes: aberrant vessel (specificity 87%), avascular focus (specificity 92%) and subcapsular vessel (specificity 100%). The vascular pattern hiliar vessel showed a significantly higher appearance in benign lymph nodes (specificity 87.8%). Conclusion: Three vascular patterns are detectable in power Doppler mode (avascular focus, aberrant vessel, subcapsular vessel) in abdominal lymph nodes, which are typical for malignant abdominal lymphadenopathy. The presence of one of these vascular patterns means with a high specificity (87 - 100%) that an abdominal lymphadenopathy is malignant. One vascular pattern (hiliar vessel) shows a significantly higher appearance in benign lymph nodes. (orig.)

  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. 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.

  2. 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 ...

  3. [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

  4. Three-dimensional laser cooling at the Doppler limit

    Science.gov (United States)

    Chang, R.; Hoendervanger, A. L.; Bouton, Q.; Fang, Y.; Klafka, T.; Audo, K.; Aspect, A.; Westbrook, C. I.; Clément, D.

    2014-12-01

    Many predictions of Doppler-cooling theory of two-level atoms have never been verified in a three-dimensional geometry, including the celebrated minimum achievable temperature ? ? /2 kB , where ? is the transition linewidth. 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 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. This discussion can be generalized to identify when a given species is likely to be subject to the same limitation.

  5. 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.

  6. 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.

  7. 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

  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. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. 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.)

  15. 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

  16. 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

  17. 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.

  18. 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.

  19. 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

  20. 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

  1. 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

  2. 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...

  3. ULTRASONOGRAFÍA DOPPLER EN EMBARAZOS DE TÉRMINO CON OLIGOHIDROAMNIOS AISLADO

    Scientific Electronic Library Online (English)

    Marcelo, Rodríguez G; Gabriela, Egaña U; Rolando, Márquez A.

    Full Text Available Objetivos: Evaluar la unidad feto placentaria, mediante ecografía Doppler fetal, en pacientes embarazadas de término con oligohidroamnios aislado (OHA) y comparar los resultados en embarazadas con líquido amniótico normal. Método: Estudio transversal de 19 pacientes con embarazo de término y OHA sin [...] patología asociada. Se compara la evaluación del Doppler con un grupo control de embarazadas con líquido amniótico normal. Como objetivo principal se mide el índice de pulsatilidad (IP) de las arterias renal, cerebral media y umbilical fetal, y como secundarios se evalúan los resultados neonatales. Resultados: Los resultados de la medición Doppler de IP en pacientes con OHA v/s control fueron no significativos: 2,03 v/s 2,04 en arteria renal (p >0,05), 1,37 v/s 1,35 en arteria cerebral media (p >0,05), 0,79 v/s 0,82 en arteria umbilical (p >0,05). Los objetivos secundarios no mostraron diferencias estadísticamente significativas. Conclusión: El OHA aislado en pacientes con embarazo de término no se asocia con alteración del Doppler fetal, por lo que no se relaciona con deterioro de la función placentaria. Abstract in english Objectives: To evaluate the fetoplacentarian unit through the fetal Doppler flow in term pregnants with oligohidramnios and to compare the fetal outcomes with term pregnants with normal amniotic fuid. Methods: We designed a transversal correlational study of 19 term patients with oligohidramnios and [...] no other pathology. We compare the fetal Doppler values with a control pregnant group with normal amniotic fluid. Our main outcomes were renal, middle cerebral and umbilical artery PI (pulsatility index) and our secondary outcomes were the neonatal results. Results: Patients with oligohidramnios PI Doppler flow values v/s control group were non significant: renal artery 2.03 v/s 2.04 (p >0.05), middle cerebral artery 1.37 v/s 1.35 (p >0.05), umbilical artery 0.79 v/s 0.82 (p>0.05). The secondary outcomes neither were statistically different. Conclusion: There is no association between the isolated oligohidramnios in a term pregnancy and fetal Doppler disorder, for what is not associated with placental dysfunction.

  4. ULTRASONOGRAFÍA DOPPLER EN EMBARAZOS DE TÉRMINO CON OLIGOHIDROAMNIOS AISLADO

    Directory of Open Access Journals (Sweden)

    Marcelo Rodríguez G

    2010-01-01

    Full Text Available Objetivos: Evaluar la unidad feto placentaria, mediante ecografía Doppler fetal, en pacientes embarazadas de término con oligohidroamnios aislado (OHA y comparar los resultados en embarazadas con líquido amniótico normal. Método: Estudio transversal de 19 pacientes con embarazo de término y OHA sin patología asociada. Se compara la evaluación del Doppler con un grupo control de embarazadas con líquido amniótico normal. Como objetivo principal se mide el índice de pulsatilidad (IP de las arterias renal, cerebral media y umbilical fetal, y como secundarios se evalúan los resultados neonatales. Resultados: Los resultados de la medición Doppler de IP en pacientes con OHA v/s control fueron no significativos: 2,03 v/s 2,04 en arteria renal (p >0,05, 1,37 v/s 1,35 en arteria cerebral media (p >0,05, 0,79 v/s 0,82 en arteria umbilical (p >0,05. Los objetivos secundarios no mostraron diferencias estadísticamente significativas. Conclusión: El OHA aislado en pacientes con embarazo de término no se asocia con alteración del Doppler fetal, por lo que no se relaciona con deterioro de la función placentaria.Objectives: To evaluate the fetoplacentarian unit through the fetal Doppler flow in term pregnants with oligohidramnios and to compare the fetal outcomes with term pregnants with normal amniotic fuid. Methods: We designed a transversal correlational study of 19 term patients with oligohidramnios and no other pathology. We compare the fetal Doppler values with a control pregnant group with normal amniotic fluid. Our main outcomes were renal, middle cerebral and umbilical artery PI (pulsatility index and our secondary outcomes were the neonatal results. Results: Patients with oligohidramnios PI Doppler flow values v/s control group were non significant: renal artery 2.03 v/s 2.04 (p >0.05, middle cerebral artery 1.37 v/s 1.35 (p >0.05, umbilical artery 0.79 v/s 0.82 (p>0.05. The secondary outcomes neither were statistically different. Conclusion: There is no association between the isolated oligohidramnios in a term pregnancy and fetal Doppler disorder, for what is not associated with placental dysfunction.

  5. 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

  6. 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)

  7. 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

  8. 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)

  9. 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...

  10. 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

  11. 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

  12. 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.

  13. Acoustic doppler methods for remote measurements of ocean flows - a review

    Digital Repository Service at National Institute of Oceanography (India)

    Joseph, A.

    The evolution of acoustic doppler methods for remote measurements of ocean flows has been briefly reviewed in historical perspective. Both Eulerian and profiling methods have been discussed. Although the first acoustic Doppler current meter has been...

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

    Directory of Open Access Journals (Sweden)

    Claudio E Scherle-Matamoros

    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.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.

  15. 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. [...

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

    OpenAIRE

    Ran, Jia; Zhang, Yewen; Chen, Xiaodong; Fang, Kai; Zhao, Junfei; Sun, Yong; 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...

  17. 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...

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Noise Studies of Externally Dispersed Interferometry for Doppler Velocimetry

    International Nuclear Information System (INIS)

    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

  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. 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.

  5. Data processing for the analysis of Doppler spectra

    International Nuclear Information System (INIS)

    A Cyber 180-830 supported, data processing code for the analysis of the Doppler broadened distribution of the photon annihilation (e+ e-) is described. This code was applied to the characterization of the various sulphur alotrophic states, studied by means of positron annihilation finding a correlation with the parameters already found by lifetime technique. (Author)

  6. Applications of doppler effect in navigation and oceanography

    Digital Repository Service at National Institute of Oceanography (India)

    Joseph, A.

    The Doppler effect is the change in frequency of the received sound waves/electromagnetic waves when there is a relative motion between the transmitter and the receiver of these waves. This effect is used for diverse applications in different areas...

  7. 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.

  8. 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.

  9. 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.

  10. Doppler measurement integration for kinematic real-time GPS positioning

    OpenAIRE

    De Agostino, Mattia; Manzino, Ambrogio

    2010-01-01

    The present paper discusses the advantages of the use of Doppler shift measurements in a Kalman filter estimator in order to improve the kinematic stand-alone global positioning system positioning performance. Tests conducted in an urban environment using a single-frequency receiver demonstrate the real advantages of the proposed real- time computation technique

  11. 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. .

  12. 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.

  13. 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.

  14. 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.)

  15. 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)

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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).

  2. 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)

  3. Language Lateralization in Children Using Functional Transcranial Doppler Sonography

    Science.gov (United States)

    Haag, Anja; Moeller, Nicola; Knake, Susanne; Hermsen, Anke; Oertel, Wolfgang H.; Rosenow, Felix; Hamer, Hajo M.

    2010-01-01

    Aim: Language lateralization with functional transcranial Doppler sonography (fTCD) and lexical word generation has been shown to have high concordance with the Wada test and functional magnetic resonance imaging in adults. We evaluated a nonlexical paradigm to determine language dominance in children. Method: In 23 right-handed children (12…

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. Planar Doppler Velocimetry for Large-Scale Wind Tunnel Applications

    Science.gov (United States)

    McKenzie, Robert L.

    1998-01-01

    Planar Doppler Velocimetry (PDV) concepts using a pulsed laser are described and the obtainable minimum resolved velocities in large-scale wind tunnels are evaluated. Velocity-field measurements are shown to be possible at ranges of tens of meters and with single pulse resolutions as low as 2 m/s. Velocity measurements in the flow of a low-speed, turbulent jet are reported that demonstrate the ability of PDV to acquire both average velocity fields and their fluctuation amplitudes, using procedures that are compatible with large-scale facility operations. The advantages of PDV over current Laser Doppler Anemometry and Particle Image Velocimetry techniques appear to be significant for applications to large facilities.

  18. Laser Doppler velocimeter measurements in a turbine stator cascade facility

    Science.gov (United States)

    Seasholtz, R. G.

    1974-01-01

    A laser Doppler velocimeter (LDV) developed for mapping the flow velocity downstream from a 32-inch diameter annular cascade of turbine stator vanes is described. The LDV measurements were taken in a plane located approximately 0.5 inch downstream of the trailing edges of the vanes. Two components of the mean velocity (axial and circumferential) were measured. The flow velocities were in the high subsonic range. The LDV optics are of the dual scatter type with off-axis collection of the scattered light. The electronics system is based on the measurement of the time interval corresponding to eight periods of the Doppler signal and has a range of 10 to 80 MHz. The LDV measurements are compared with previous measurements made with a pressure probe.

  19. 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

  20. 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.

  1. Conventional and Doppler ultrasonography on a goat with gangrenous mastitis

    Directory of Open Access Journals (Sweden)

    V.J.C. Santos

    2014-12-01

    Full Text Available Objetivou-se descrever os achados clínicos e ultrassonográficos de uma cabra leiteira apresentando mastite gangrenosa. Com a ultrassonografia convencional, observaram-se alterações consistentes com o avanço do quadro clínico, como alterações na ecogenicidade do leite e parênquima mamário. A ultrassonografia Doppler revelou aumento da velocidade de pico sistólico nos três momentos estudados, passando de 15 para 17 e 29cm/s. Houve redução, também, dos valores do índice de resistência, de 0,71 para 0,61 e 0,43. O índice de pulsatividade sofreu redução entre o segundo e o terceiro dia de observação, passando de 0,98 para 0,71. Foi possível estabelecer relação direta entre os achados ultrassonográficos e a gravidade da doença. A ultrassonografia convencional e Doppler podem ser utilizadas para o estudo hemodinâmico do úbere de cabras leiteiras, favorecendo diagnóstico e prognóstico de alterações nesse órgão.

  2. 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

  3. 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.

  4. 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

  5. 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

  6. 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.

  7. 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

  8. 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

  9. 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.

  10. 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.

  11. 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...

  12. Three-dimensional laser cooling at the Doppler limit

    OpenAIRE

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

    2014-01-01

    Many predictions of Doppler cooling theory of two-level atoms have never been verified in a three-dimensional geometry, including the celebrated minimum achievable temperature $\\hbar \\Gamma/2 k_B$, where $\\Gamma$ is the transition linewidth. 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 s...

  13. Preoperative risk assessment for carotid occlusion by transcranial Doppler ultrasound.

    OpenAIRE

    Schneweis, S; Urbach, H; Solymosi, L; Ries, F

    1997-01-01

    OBJECTIVES: An endovascular carotid balloon occlusion test with continuous intracranial monitoring by transcranial Doppler sonography was performed in 55 patients for prediction of tolerance of a required permanent occlusion of the carotid artery. METHODS: Blood flow velocities of the ipsilateral middle cerebral artery during occlusion were recorded and compared with clinical tolerance during an occlusion test as well as with postoperative outcome after an eventual permanent occlusion. To str...

  14. 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.

  15. 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.

  16. 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 ...

  17. 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...

  18. 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.

  19. 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.

  20. Transcranial Doppler ultrasonography predicts cardiovascular events after TIA

    OpenAIRE

    Sander Dirk; Bockelbrink Angelina; Esposito Lorena; Sadikovic Suwad; Holzer Katrin; Hemmer Bernhard; Poppert Holger

    2009-01-01

    Abstract Background Transient ischemic attack (TIA) patients are at high vascular risk. We assessed the value of extracranial (ECD) and transcranial (TCD) Doppler and duplex ultrasonography to predict clinical outcome after TIA. Methods 176 consecutive TIA patients admitted to the Stroke Unit were recruited in the study. All patients received diffusion-weighted imaging, standardized ECD and TCD. At a median follow-up of 27 months, new vascular events were recorded. Results 22 (13.8%) patients...

  1. Image Segmentation Algorithms and their use on Doppler Images

    OpenAIRE

    Tatiana D. C. A. Silva; Zhen Ma; Tavares, João Manuel R. S.

    2011-01-01

    This paper aims to make a review on current segmentation algorithms used for medical images. Image segmentation algorithms can be classified according to their methodologies, namely the ones based on thresholds, clustering, and deformable models. Each type of algorithms is discussed as well as their main application fields identified; additionally, the advantages and disadvantages of each type are pointed out. Experiments that apply the algorithms to segment Doppler images are presented to fu...

  2. 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 ...

  3. 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.)

  4. Doppler imaging of the helium-variable star a Cen

    OpenAIRE

    Bohlender, David A.; Rice, J B; Hechler, P.

    2010-01-01

    The helium-peculiar star a Cen exhibits line profile variations of elements such as iron, nitrogen and oxygen in addition to its well-known extreme helium variability. New high S/N, high-resolution spectra are used to perform a quantitative measurement of the abundances of the star and determine the relation of the concentrations of the heavier elements on the surface of the star to the helium concentration and the magnetic field orientation. Doppler images have been created...

  5. 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 ...

  6. Zeeman-Doppler Imaging : Old Problems and New Methods

    OpenAIRE

    Carroll, T. A.; Kopf, M.; K. G. Strassmeier; Ilyin, I

    2009-01-01

    Zeeman-Doppler Imaging (ZDI) is a powerful inversion method to reconstruct stellar magnetic surface fields. The reconstruction process is usually solved by translating the inverse problem into a regularized least-square or optimization problem. In this contribution we will emphasize that ZDI is an inherent non-linear problem and the corresponding regularized optimization is, like many non-linear problems, potentially prone to local minima. We show how this problem will be ex...

  7. Evaluation of the MV (CAPON) Coherent Doppler Lidar Velocity Estimator

    Science.gov (United States)

    Lottman, B.; Frehlich, R.

    1997-01-01

    The performance of the CAPON velocity estimator for coherent Doppler lidar is determined for typical space-based and ground-based parameter regimes. Optimal input parameters for the algorithm were determined for each regime. For weak signals, performance is described by the standard deviation of the good estimates and the fraction of outliers. For strong signals, the fraction of outliers is zero. Numerical effort was also determined.

  8. Teaching Doppler Effect with a passing noise source

    Science.gov (United States)

    Costa, Ivan F.; Mocellin, Alexandra

    2010-07-01

    The noise pitch variation of a passing noise source allows a low cost experimental approach to calculate speed and, for the first time, distance. We adjusted the recorded noise pitch variation to the Doppler shift equation for sound. We did this by taking into account the frequency delay due to the sound source displacement and performing a Fast Fourier Transform (FFT) of the noise signal using free software. This experimental method was successfully applied to aircraft and automobiles.

  9. CO2 measurements during transcranial Doppler examinations in headache patients

    DEFF Research Database (Denmark)

    Thomsen, L L; Iversen, Helle Klingenberg

    1994-01-01

    Transcranial Doppler (TCD) examinations are increasingly being used in studies of headache pathophysiology. Because blood velocity is highly dependent on PCO2, these parameters should be measured simultaneously. The most common way of performing measurements during TCD examinations is as end-tidal pCO2 with a capnograph. When patients are nauseated and vomit, as in migraine, the mask or mouthpiece connected to the capnograph represents a problem. We therefore evaluated whether a transcutaneous p...

  10. Radiation pressure on a moving body: beyond the Doppler effect

    OpenAIRE

    Horsley, S. A. R.; Artoni, M.; La Rocca, G. C.

    2011-01-01

    The dependence of macroscopic radiation pressure on the velocity of the object being pushed is commonly attributed to the Doppler effect. This need not be the case, and here we highlight velocity dependent radiation pressure terms that have their origins in the mixing of s and p polarizations brought about by the Lorentz transformation between the lab and the material rest frame, rather than in the corresponding transformation of frequency and wavevector. The theory we devel...

  11. Doppler ultrasonography of hepatic artery in malignant liver tumors

    Directory of Open Access Journals (Sweden)

    Periši? Mirjana

    2008-01-01

    Full Text Available Hepatic artery is dominant compared to portal vein in liver tumor vascularization. Malignant tumors have uncontrolled growth and spread onto neighbouring tissues through a tumor vascular network. Based on this we discussed the use arterial flow parameters including systolic and diastolic speed, Doppler perfusion index, and resistance index for early detection of liver metastasis. We also discussed possibility to make differential diagnosis from other disease such as arterial stenosis, liver cirrhosis, steatosis using these parameters in better diagnosis confirmation.

  12. Probing Lorentz violation with Doppler-shift experiments

    OpenAIRE

    Lane, Charles D.

    2005-01-01

    We analyze Doppler-effect experiments in terms of a general framework for violations of Lorentz symmetry: the Standard-Model Extension. These experiments are found to be sensitive to heretofore unprobed combinations of Lorentz-violation coefficients associated with protons and electrons. New bounds at the level of $10^{-11}$ and $10^{-8}$ for proton coefficients and $10^{-2}$ for electron coefficients emerge from a recent experiment.

  13. Doppler effect and frequency-shift in optics

    OpenAIRE

    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 ...

  14. Doppler effect in the oscillator radiation process in the medium

    OpenAIRE

    Gevorgian, Lekdar; Vardanyan, Valeri

    2011-01-01

    The purpose of this paper is to investigate the radiation process of the charged particle passing through an external periodic field in a dispersive medium. In the optical range of spectrum we will consider two cases: first, the source has not eigenfrequency, and second, the source has eigenfrequency. In the first case, when the Cherenkov radiation occurs, the non-zero eigenfrequency produces a paradox for Doppler effect. It is shown that the absence of the eigenfrequency so...

  15. Doppler methods of search and monitoring of exoplanets

    Science.gov (United States)

    Panchuk, V. E.; Klochkova, V. G.; Sachkov, M. E.; Yushkin, M. V.

    2015-12-01

    The main stages of the development of Doppler methods of search and study of extrasolar planetary systems (exoplanets) are described. The main instrumental and methodological effects that influence the measurement accuracy of spectral line positions in the study of exoplanets are considered. The development of the domestic spectrograph for spectroscopic monitoring with high-precision determination of radial velocities is reported. Directions for further development of high-resolution spectroscopy are discussed.

  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. Duplex colour Doppler sonography — role in neck metastasis

    OpenAIRE

    Puri, R.; Srinath, V. S.; Chakravarti, A. L.

    2002-01-01

    The present study was done to evaluate the rote of Duplex colour Doppler Sonography in neck metastasis. 30 patients with primary head and neck cancer were evaluated by Duplex colour Doppier sonography and results analysed. In more than 95% of cases, the vascular status could be established before any form of therapy was instituted. Compression and infiltration of carotids and internal jugular vein (IJV) could be demonstrated and a structured and dynamic relationship of metastatic nodes to the...

  18. 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 of synovitis, guidance of steroid injections, and follow-up examinations of the wrist in JIA.

  19. Color Doppler in the Assessment of Uteroplacental Circulation Insufficiency

    OpenAIRE

    Ahmad Soltani Shirazi

    2010-01-01

    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 ins...

  20. Doppler velocity assessment of venous return in the human fetus

    OpenAIRE

    Huisman, T.W.A.

    1993-01-01

    Studies in the human fetus are limited by the methods available for investigation. Pressure and volume flow measurements in the fetal cardiovascular system require invasive techniques that are not performed at present. However, information on fetal circulatory performance may be helpful in the evaluation of pathologic conditions. With the introduction of Doppler ultrasound non-invasive examination of the fetal vessels became possible. In the last decade cardiovascular resear...

  1. Holographic laser Doppler imaging of microvascular blood flow.

    Science.gov (United States)

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

    2014-12-01

    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 radio frequency 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 radio frequencies, 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 0.1-10 mm/s range in vitro and imaging of superficial blood perfusion with a spatial resolution of about 10 micrometers in rodent models of cortical and retinal blood flow. PMID:25606762

  2. Color doppler flow mapping of prosthetic heart valves

    International Nuclear Information System (INIS)

    Seventy Doppler velocity/flow studies of 23 different types of clinical and preclinical valves were performed after implantation in the mitral position in an animal model system. Sixty-four studies were performed early (0-10) days after implantation and 6 were performed 20 weeks after implantation. Color Doppler velocity/flow profiles were imaged in real-time and with electrocardiographic gating (Aloka system 880). The study protocol included imaging at 10 ms intervals throughout ventricular diastole and systole. Two carrier frequencies (2.5 and 5 MHz) and 3 pulsed repetition frequencies (4, 6 and 8 kHz) were used for a total of 5 maximal resolvable velocities without aliasing from 31 to 121 cm/s overall range of 4 to 121 cm/s). Velocities which aliased in the pulsed modes were quantified utilizing continuous wave Doppler with an independent transducer (Pedoff) or a dual function transducer. Three orthogonal planes were used. Studies were performed at 3 heart rates ranging from 60 - 120/min and at cardiac outputs ranging from 2 - 3.5 1/min, which were within the normal ranges for these animals

  3. Development of Point Doppler Velocimetry for Flow Field Investigations

    Science.gov (United States)

    Cavone, Angelo A.; Meyers, James F.; Lee, Joseph W.

    2006-01-01

    A Point Doppler Velocimeter (pDv) has been developed using a vapor-limited iodine cell as the sensing medium. The iodine cell is utilized to directly measure the Doppler shift frequency of laser light scattered from submicron particles suspended within a fluid flow. The measured Doppler shift can then be used to compute the velocity of the particles, and hence the fluid. Since this approach does not require resolution of scattered light from individual particles, the potential exists to obtain temporally continuous signals that could be uniformly sampled in the manner as a hot wire anemometer. This leads to the possibility of obtaining flow turbulence power spectra without the limitations of fringe-type laser velocimetry. The development program consisted of a methodical investigation of the technology coupled with the solution of practical engineering problems to produce a usable measurement system. The paper outlines this development along with the evaluation of the resulting system as compared to primary standards and other measurement technologies.

  4. Modelling nonstationary Doppler noise in exoplanetary radial velocity data

    Science.gov (United States)

    Baluev, Roman V.

    2015-08-01

    We construct a new class of analytic nonstationary noise models for exoplanetary Doppler data. The observable correlated noise is represented as a convolution of a parent activity process with a given memory function. The model honours the casuality principle, meaning that only past values of the activity may affect the observable value. This model does not approximate detailedly any real stellar activity phenomena, but it becomes mathematically simple, simultaneously satisfying the basic natural principles of physical sensibility and self-consistency.Additionally, we develop a new type of periodograms that can be used to detect periodic modulations in the Doppler noise characteristics, rather than in the observed radial velocity curve itself. We present first results of applying this technique to public Doppler time series available for a set of planet-hosting stars.This work was supported by the Russian Foundation for Basic Research (project No. 14-02-92615 KO_a), the UK Royal Society International Exchange grant IE140055, by the President of Russia grant for young scientists (No. MK-733.2014.2), by the programme of the Presidium of Russian Academy of Sciences P21, and by the Saint Petersburg State University research grant 6.37.341.2015.

  5. Doppler radar wind field retrieval over the Po Valley

    Directory of Open Access Journals (Sweden)

    Y. K. Goh

    2006-01-01

    Full Text Available 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 wind field syntheses are carried out on a 30 km by 30 km region where the two radars have overlapping scan coverage. An iterative method based on the linear wind model and the equation of mass continuity is used to construct the wind fields. The methodology has been validated by two different methods. The first method is to reconstruct the radial wind observed by each radar, and the second method is calculating and comparing the along-track component with that derived from the observations. Both two comparisons show good agreement with the original data.

  6. Color Doppler in the Assessment of Uteroplacental Circulation Insufficiency

    Directory of Open Access Journals (Sweden)

    Ahmad Soltani Shirazi

    2011-05-01

    Full Text Available Color Doppler ultrasound in diagnosis of uteroplacental"nor fetal placental vascular insufficiency is based on"nthe theory that many of these insufficiencies are"ndue to small vessel disease in uteroplacental or fetal"nplacental vasculature which ultimately results in fetal"nintrauterine growth retardation, increase in prenatal"nmortality and morbidity and fetal neurological"ndevelopment."nIn a prospective study on patients who were suspected"nfor developing uteroplacental insufficiency, color"nDoppler ultrasound was done and the results were"ncompared with the neonatal weight which was"nmeasured just after delivery."nAbstracts"nS66 Iran J Radiol 2011, 8 (Supp.1"nDirect significant correlation was showed to be present"nbetween prepartum vascular changes detected in"nDoppler ultrasound and the prognosis of IUGR."nThree vessel types were assessed in this study: 1-"numbilical -middle cerebral arteries 2-uterine arteries"n3-venous system (umblical vein, ductus venosus, IVC,"nwhich are used to assess the compensation process in"nfetal circulation.

  7. Sub-Doppler laser cooling of metastable He

    International Nuclear Information System (INIS)

    We have observed magnetically induced laser cooling (MILC) on the J = 1 ? 2 component of the 23S ? 23P transition at ? = 1.083 ?m in metastable helium (He*). At low magnetic field the measured widths of our atomic velocity distributions are as narrow as 2?k/M corresponding to a temperature ? 3 ?K (1-D Doppler limit ? 26 ?K). At higher fields (?150 mG) the velocity distribution splits into two peaks of sub-Doppler width whose separation is proportional to the Zeeman splitting. Our measurements are consistent with model calculations based on the time evolution of quantum density matrices. Our experiments explore the transition regime between the quantum mechanical and semiclassical models of momentum exchange in atom-light interactions because of the large ratio (0.4) of the recoil velocity ?k/M to the rms of the Doppler-limited velocity distribution ???/3M for this transition. We use a supersonic LN2 cooled nozzle source excited by a dc discharge for He*, and we excite the 23P state with a home-built diode-laser-pumped LNA laser

  8. Doppler effect in the oscillator radiation process in the medium

    CERN Document Server

    Gevorgian, Lekdar

    2011-01-01

    The purpose of this paper is to investigate the radiation process of the charged particle passing through an external periodic field in dispersive medium. In the optical range of spectrum we will consider two cases: first - the source has not eigen frequency, and second - the source has eigen frequency. In the first case, when the Cherenkov radiation occurs, the non-zero eigen frequency produces a paradox for Doppler Effect. It is shown that the absence of the eigen frequency solves the paradox known in the literature. The question whether the process is normal (i.e. hard photons are being radiated under the small angles) or anomalous depends on the law of the medium dispersion. When the source has an eigen frequency the Doppler Effects can be either normal or anomalous. In the X-ray range of oscillator radiation spectrum we have two photons radiated under the same angle - soft and hard. In this case the radiation obeys to so called complicated Doppler effect, i.e. in the soft photon region we have anomalous ...

  9. Estimation of Carotid Artery Pulse Wave Velocity by Doppler Ultrasonography

    Directory of Open Access Journals (Sweden)

    Mehdi Maerefat

    2009-06-01

    Full Text Available Background: Pulse wave velocity (PWV is widely used for estimating the stiffness of an artery. Various invasive and non-invasive methods have been developed to determine PWV over the years. In the present research, the non-invasive estimation of the PWV of large arteries was used as an index for arterial stiffness. Methods: A dynamic model based on the Navier-Stokes equations coupled to elasticity equations was introduced for the PWV in arteries with elastic walls. This system of equations was completed by clinical information obtained from the Doppler ultrasound images of the carotid artery of 40 healthy male volunteers. For this purpose, the Doppler ultrasound images were recorded and saved in a computer; and subsequently center-line blood velocity, arterial wall thickness, and arterial radius were measured by offline processing. Results: The results from the analytic solution of the completed equations showed that the mean value of PWV for the group of healthy volunteers was 2.35 m/s when the mean arterial radius was used as the neutral radius and 5.00 m/s when the end-diastole radius was used as the neutral radius. It is noteworthy that the latter value closely complies with that reported by other researchers. Conclusion: By applying this method, a non-invasive clinical and local evaluation of the common carotid artery stiffness via a Doppler ultrasound measurement will be possible.

  10. Flujometría Doppler patológica y su correlación con el pronóstico perinatal a corto plazo / Pathologic Doppler velocimetry and correlation with perinatal prognosis at short term

    Scientific Electronic Library Online (English)

    Igor, Huerta; Aída, Borcic.

    Full Text Available Objetivos: Determinar la morbilidad y mortalidad de fetos con flujometría Doppler patológico y evaluar discapacidades en el corto plazo. Diseño: Estudio tipo retrospectivo, observacional, analítico, correlacional. Lugar: Unidad de vigilancia fetal, Hospital Nacional Edgardo Rebagliati Martins, Red A [...] sistencial Rebagliati, EsSalud, Lima, Perú. Participantes: Gestantes con flujometría Doppler patológicos y sus perinatos. Intervenciones: Se estudió todos los casos de gestantes con flujometría Doppler alterado, entre febrero de 2008 y febrero de 2010. Se agrupó por tipos de flujometría Doppler y se describió la frecuencia de patología y morbimortalidad perinatal, correlacionándolas con la edad gestacional. El análisis se realizó con el paquete estadístico SPSS 11,0, la prueba chi cuadrado para las variables discretas y la de Kruskal-Wallis, para las variables continuas. Se asumió un valor de significancia de p Abstract in english Objectives: To determine both morbidity and mortality in fetuses with pathological Doppler velocimetry and short term handicap. Design: Retrospective, observational, analytical, correlation study. Setting: Fetal surveillance unit, Hospital Nacional Edgardo Rebagliati Martins, Red Asistencial Rebagli [...] ati, EsSalud, Lima, Peru. Participants: Pregnant women with pathological Doppler velocimetry and their perinates. Interventions: All pregnant women with altered Doppler velocimetry between February 2008 and February 2010 were studied. They were grouped by Doppler velocimetry types, and frequency of pathology; perinatal morbidity and mortality were determined and correlated with gestational age. SPSS 11,0 was used for statistical analysis, chi square test for discrete variables and Kruskal-Wallis test for continued variables. Significant value was p

  11. Estudo da macrovasculatura por ultra-sonografia Doppler na esclerose sistêmica / Study of macrovasculature by Doppler ultrasound in systemic sclerosis

    Scientific Electronic Library Online (English)

    Emmanuelle Tenório Albuquerque Madruga, Godoi; Alexandre Domingues, Barbosa; Juannicelle Tenório Albuquerque Madruga, Godoi; Mariana Atanásio Morais, Ramos; Jocelene Tenório Albuquerque Madruga, Godoi; Sílvio Romero de Barros, Marques; Ângela Luzia Branco Pinto, Duarte.

    2008-04-01

    Full Text Available OBJETIVO: Avaliar a ocorrência e a distribuição das alterações macrovasculares em uma população com esclerose sistêmica (ES) por meio da ultra-sonografia Doppler (USG Doppler) e do índice tornozelo-braço (ITB). Foi investigada a associação destes achados com as características demográficas e clínica [...] s dos pacientes, bem como fatores de risco e antecedentes da doença ateromatosa. MÉTODOS: Estudo prospectivo, tipo série de casos, constituído de 20 pacientes, sendo 19 do sexo feminino, com idade média de 46,30 anos. A forma clínica difusa esteve presente em 85% dos pacientes. Todos tinham fenômeno de Raynaud (FR), 55% apresentaram alteração de polpas digitais, 15% úlcera atual de membros e 25% reabsorção de falange. Não houve amputação e 70% apresentaram de um a quatro fatores de risco de aterosclerose. A aorta, as carótidas, bem como as artérias dos membros superiores (MMSS) e inferiores (MMII) foram estudadas por USG Doppler para a avaliação de espessamento do complexo íntima-medial (CIM), presença de placas e aneurismas. Nas artérias dos MMII, foi também realizado o ITB. RESULTADOS: O ITB foi normal em todos os pacientes, entretanto 12 (60%) destes apresentaram doença macrovascular (DMV), sendo 9 (45%) na aorta, 7 (35%) nos MMII, 6 (30%) nas carótidas e 1 (5%) nas artérias dos MMSS. Observou-se associação entre DMV e alterações de polpas digitais (p = 0,0045). CONCLUSÕES: A USG Doppler identificou DMV em 60% dos pacientes com ES. Nenhum paciente apresentou ITB anormal. Verificou-se associação significante da DMV com as alterações atuais de polpas digitais. As alterações macrovasculares encontradas não estão necessariamente associadas à esclerose sistêmica e podem decorrer do processo aterosclerótico. Abstract in english OBJECTIVE: To assess the occurrence and distribution of the macrovascular alterations in a population with Systemic Sclerosis (SS) by means of Doppler ultrasound (Doppler US) and ankle-arm index (AAI). To investigate the assotiation of these findings with both demographic and clinical characteristic [...] s in the patients as well as with risk factors and antecedents of atheromatous disease. METHODS: Prospective study, of the series of cases type, comprising 20 patients, 19 of whom were women with a median age of 46.30 years. Eighty-five percent were of the diffuse form. All the patients had the Raynaud's phenomenon, 55% presented alteration of digital pulps, 15% current limb ulcers and 25% phalanx resorption. There were no amputations and 70% presented from 1 to 4 risk factors for atherosclerosis. The aorta, carotids as well as upper (ULs) and lower (LLs) limbs arteries were evaluated by Doppler US to assess thickening of the medio-intimal complex (MIC), presence of plaques and aneurisms. In the arteries of the LLs, AAI was also undertaken. RESULTS: AAI was normal in all patients, 12 patients (60%) presented macrovascular disease (MVD) comprising 9 (45%) of these in the aorta, 7 (35%) in LLs arteries , 6 (30%) in the carotids and 1 (5%) in ULs arteries. MVD and alterations of digital pulps were positivily associated (p = 0.0045). CONCLUSIONS: Doppler US identified MVD in 60% of our SS patients. No patients had abnormal AAI. MDV was positivily associated with digital pulps alterations. The macrovascular alterations found are not necessarily associated with systemic sclerosis, and may be due to atherosclerosis process.

  12. Estudo da macrovasculatura por ultra-sonografia Doppler na esclerose sistêmica Study of macrovasculature by Doppler ultrasound in systemic sclerosis

    Directory of Open Access Journals (Sweden)

    Emmanuelle Tenório Albuquerque Madruga Godoi

    2008-04-01

    Full Text Available OBJETIVO: Avaliar a ocorrência e a distribuição das alterações macrovasculares em uma população com esclerose sistêmica (ES por meio da ultra-sonografia Doppler (USG Doppler e do índice tornozelo-braço (ITB. Foi investigada a associação destes achados com as características demográficas e clínicas dos pacientes, bem como fatores de risco e antecedentes da doença ateromatosa. MÉTODOS: Estudo prospectivo, tipo série de casos, constituído de 20 pacientes, sendo 19 do sexo feminino, com idade média de 46,30 anos. A forma clínica difusa esteve presente em 85% dos pacientes. Todos tinham fenômeno de Raynaud (FR, 55% apresentaram alteração de polpas digitais, 15% úlcera atual de membros e 25% reabsorção de falange. Não houve amputação e 70% apresentaram de um a quatro fatores de risco de aterosclerose. A aorta, as carótidas, bem como as artérias dos membros superiores (MMSS e inferiores (MMII foram estudadas por USG Doppler para a avaliação de espessamento do complexo íntima-medial (CIM, presença de placas e aneurismas. Nas artérias dos MMII, foi também realizado o ITB. RESULTADOS: O ITB foi normal em todos os pacientes, entretanto 12 (60% destes apresentaram doença macrovascular (DMV, sendo 9 (45% na aorta, 7 (35% nos MMII, 6 (30% nas carótidas e 1 (5% nas artérias dos MMSS. Observou-se associação entre DMV e alterações de polpas digitais (p = 0,0045. CONCLUSÕES: A USG Doppler identificou DMV em 60% dos pacientes com ES. Nenhum paciente apresentou ITB anormal. Verificou-se associação significante da DMV com as alterações atuais de polpas digitais. As alterações macrovasculares encontradas não estão necessariamente associadas à esclerose sistêmica e podem decorrer do processo aterosclerótico.OBJECTIVE: To assess the occurrence and distribution of the macrovascular alterations in a population with Systemic Sclerosis (SS by means of Doppler ultrasound (Doppler US and ankle-arm index (AAI. To investigate the assotiation of these findings with both demographic and clinical characteristics in the patients as well as with risk factors and antecedents of atheromatous disease. METHODS: Prospective study, of the series of cases type, comprising 20 patients, 19 of whom were women with a median age of 46.30 years. Eighty-five percent were of the diffuse form. All the patients had the Raynaud's phenomenon, 55% presented alteration of digital pulps, 15% current limb ulcers and 25% phalanx resorption. There were no amputations and 70% presented from 1 to 4 risk factors for atherosclerosis. The aorta, carotids as well as upper (ULs and lower (LLs limbs arteries were evaluated by Doppler US to assess thickening of the medio-intimal complex (MIC, presence of plaques and aneurisms. In the arteries of the LLs, AAI was also undertaken. RESULTS: AAI was normal in all patients, 12 patients (60% presented macrovascular disease (MVD comprising 9 (45% of these in the aorta, 7 (35% in LLs arteries , 6 (30% in the carotids and 1 (5% in ULs arteries. MVD and alterations of digital pulps were positivily associated (p = 0.0045. CONCLUSIONS: Doppler US identified MVD in 60% of our SS patients. No patients had abnormal AAI. MDV was positivily associated with digital pulps alterations. The macrovascular alterations found are not necessarily associated with systemic sclerosis, and may be due to atherosclerosis process.

  13. Conventional and Doppler ultrasonography on a goat with gangrenous mastitis / Ultrassonografia convencional e Doppler em cabra com mastite gangrenosa

    Scientific Electronic Library Online (English)

    V.J.C., Santos; K.M.M.G., Simplício; D.C.C., Sanchez; V.T., Almeida; P.P.M., Teixeira; L.N., Coutinho; L.F.S., Rodrigues; M.E.F., Oliveira; M.A.R., Feliciano; W.R.R., Vicente.

    2014-12-01

    Full Text Available Objetivou-se descrever os achados clínicos e ultrassonográficos de uma cabra leiteira apresentando mastite gangrenosa. Com a ultrassonografia convencional, observaram-se alterações consistentes com o avanço do quadro clínico, como alterações na ecogenicidade do leite e parênquima mamário. A ultrasso [...] nografia Doppler revelou aumento da velocidade de pico sistólico nos três momentos estudados, passando de 15 para 17 e 29cm/s. Houve redução, também, dos valores do índice de resistência, de 0,71 para 0,61 e 0,43. O índice de pulsatividade sofreu redução entre o segundo e o terceiro dia de observação, passando de 0,98 para 0,71. Foi possível estabelecer relação direta entre os achados ultrassonográficos e a gravidade da doença. A ultrassonografia convencional e Doppler podem ser utilizadas para o estudo hemodinâmico do úbere de cabras leiteiras, favorecendo diagnóstico e prognóstico de alterações nesse órgão. Abstract in english [...

  14. As diferenças do Doppler espectral, na artrite psoriática e onicomicose / Differences of spectral Doppler in psoriatic arthritis and onychomycosis

    Scientific Electronic Library Online (English)

    José Alexandre, Mendonça.

    2014-12-01

    Full Text Available Objetivo Utilizar o Doppler espectral (DE) para quantificar atividade inflamatória e detectar diferenças ecotexturais ungueais em pacientes com artrite psoriásica e onicomicose. Métodos Foram incluídos dois pacientes, um com artrite psoriásica, mas sem dores nas articulações e sem alterações clín [...] icas ungueais; e outro paciente com onicomicose e artrite reumatoide. O exame de ultrassom, pela escala cinza, demonstrou alterações na presença regular da ecotextura na inserção da unha, aumento da espessura do leito ungueal e perda do padrão trilaminar da unha. O Doppler espectral, através do índice de resistência (IR), detecta o processo inflamatório nas enteses ungueais. Resultados Sete articulações interfalângicas distais (IFD) nos dois pacientes foram avaliadas em dois planos, obtendo nove IR. O autor encontrou no paciente com artrite psoriásica: perda normal do padrão trilaminar da unha; leitos ungueais e cápsulas articulares das IFDs preservados. O Doppler espectral evidenciou IR1, com média±DP igual a 1,71±0,98. Conclusão O uso do ultrassom pode detectar alterações nos leitos ungueais nessas doenças. Futuros estudos poderão melhor caracterizar essas mudanças. Abstract in english Objective To evaluate the use of the spectral Doppler (SDoppler) to quantify inflammatory activity and to detect nail echotextural differences in patients with psoriatic arthritis and onychomycosis. Methods Two patients, one with psoriatic arthritis but with no joint pain nor nail clinical change [...] and the other with onychomycosis and rheumatoid arthritis were included. The gray scale ultrasound study, showed changes in the regular presence of echotexture at the nail insertion, thickening of the nail bed and loss of trilaminar nail pattern. The spectral Dopplerresistance index (RI), detects the inflammatory process in nail entheses. Results Seven distal interphalangeal (DIP) joints in both patients were evaluated in two planes, getting nine RI. In the patient with psoriatic arthritis the author found: loss of normal trilaminar nail plate aspect, and nail beds and DIP joint capsules preserved. The spectral Doppler showed RI1, with mean±SD=1.71±0.98. Conclusion The use of ultrasound can detect changes in the nail beds in these diseases. Future studies will further characterize these changes.

  15. Aspectos psicológicos y Doppler-Duplex dinámico en disfunción eréctil / Psychological features and Doppler-Duplex in erectile disfunction

    Scientific Electronic Library Online (English)

    M.A., Fernández-Gil; L., Martínez-Piñeiro; M., Martí; F.J., Vaz Leal; J.A., Guisado Macías.

    2005-10-01

    Full Text Available Objetivo: Relacionar los hallazgos de la ecografía Doppler-Duplex color tras la inyección intracavernosa de prostaglandina con los aspectos psicológicos en pacientes con disfunción eréctil (DE). Material y método: Se estudiaron, de forma prospectiva, 42 pacientes con DE mediante ecografía Doppler-Du [...] plex color tras la inyección de 20 microgramos de PGE1 intracavernosa. Se evaluaron los patrones morfodinámicos y de flujo. Se graduó visualmente la tumescencia peneana en pobre, moderada o buena (I, II, III). Todos los pacientes completaron el Índice Internacional de Función Eréctil (IIFE). Para el estudio psicológico de los pacientes se utilizó el examen Internacional de los Trastornos de la Personalidad (IPDE, módulo CIE-10) y Symptom Checlist 90-Revised (SCL-90R). Resultados: 29 pacientes (69.05%) mostraron una respuesta normal en el estudio ecográfico (velocidad picosistólica >30 cm/s; velocidad telediastólica negativa o Abstract in english Objectives: To establish a relationship between Doppler-Duplex colour ultrasound after prostaglandin intracorporeal injection and psychological features in patients suffering from erectile dysfunction. Methods: Forty two patients with erectile dysfunction were prospectively evaluated with Doppler-Du [...] plex colour ultrasonography after intracavernosal injection of 20 micrograms of E1 prostaglandin. Dynamic vascular pattern were analyzed and penile tumescence were graded in poor, moderate or good (I, II, III). All of them completed the International Index of Erectile Dysfunction, International Exam of Personality Traits (IPDE) and the Symptom Checklist (SCL-90). Results: 29 patients (69.05%) showed a normal ultrasonography response (Peak Systolic Velocity >30 cm/s; Telediastolic velocity negative or less than 5cm/s and penile tumescence grade III) and were classified as good responders with probably psychogenic erectile dysfunction. Patients who did not show these values were classified in the group of erectile dysfunction of vascular origin. We found significative differences between the two groups in sex desire, tumescence and paranoid personality. The more frequent personality features were paranoid and squizoid (excentric) and ananchastic and anxious (fearful ones). Somatization and obsessive-compulsive symptoms have been outlined over the rest. We have found that paranoid personality is sixteen times more frequent in patients with normal ultrasonography. Conclusions: Psychological features and dysfunctional personality traits accompany psychogenic and organic erectile dysfunction, thus it is thought that mixed aetiology coexist in this patients. Doppler-Dupplex Colour ultrasound is an useful method to exclude organic vascular factors. On de basis of our article, is more common to find psychological discomfort and dysfunctional personality traits in patients with normal ultrasound, which may help in their diagnosis and treatment.

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

    Science.gov (United States)

    Ran, Jia; Zhang, Yewen; Chen, Xiaodong; Fang, Kai; Zhao, Junfei; Sun, Yong; Chen, Hong

    2015-06-01

    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 reconfigurable RF metamaterial structure, which can exhibit anomalous dispersion, normal dispersion or a stop band, depending on an applied bias voltage. Either inverse or normal Doppler shift is realized by injecting an external RF signal into the electronically reconfigurable metamaterial, on which an electronically controllable moving reflective boundary is formed. The effective velocity of this boundary and the resulting frequency shift can be tuned over a wide range by a digital switching circuit. This work is expected to open up possibilities in applying the inverse Doppler effect in wireless communications, radar and satellite navigation.

  17. A model for the simulation of Doppler ultrasound signal from pulsatic blood flow

    OpenAIRE

    Bastos, Carlos Alberto da Costa

    1999-01-01

    O detector ultra-sónico de fluxo sanguíneo usa o efeito Doppler para estimar de forma não invasiva a velocidade do sangue na circulação. Tem sido bastante usado nas ultimas quatro décadas para detectar a presença de estenoses. O desenvolvimento de novas técnicas de processamento do sinal Doppler necessita de sinais de teste cujas características sejam conhecidas ou possam ser medidas com precisão. Isto é difícil de obter com sinais Doppler medidos in vivo devido à elevada va...

  18. Micro-Doppler Frequency Estimation Based on Radon-Wigner Transform

    Directory of Open Access Journals (Sweden)

    Sun Huixia

    2014-01-01

    Full Text Available A nonparametric computationally efficient algorithm is proposed for micro-Doppler frequency estimation, assuming that this non-linear micro-Doppler frequency is approximate linear frequency in short-time intervals. In this algorithm, we use Radon-Wigner transform in short-time intervals to estimate micro-Doppler frequency. Simulation results confirm the effectiveness of the proposed method.Defence Science Journal, Vol. 64, No. 1, January 2014, DOI:10.14429/dsj.64.2980

  19. Pulsed and Tissue Doppler Echocardiographic Changes in Patients with Thalassemia Major

    OpenAIRE

    Taysir S. Garadah; Salah Kassab; Najat Mahdi; Ahmed Abu-Taleb; Anwer Jamsheer

    2010-01-01

    Background: Doppler echocardiographic studies of left ventricle (LV) systolic and diastolic function in patients with ?-Thalassemia Major (?-TM) had shown different patterns of systolic and diastolic dysfunction. Aim: This cross-sectional study was designed to study the LV systolic and diastolic function in patients with ?-TM using Pulsed Doppler (PD) and Tissue Doppler (TD) echocardiography. Methods: All patients were evaluated clinically and by echocardiography, The study included patients ...

  20. Effects of testicular microlithiasis on Doppler parameters: report of three cases

    OpenAIRE

    Alkan Alpay; Baysal Tamer; Sigirci Ahmet; Kutlu Ramazan; Sarac Kaya

    2002-01-01

    Abstract Background Testicular microlithiasis is a rare, usually asymptomatic, non-progressive disease of the testes associated with various genetic anomalies, infertility and testicular tumors. According to our literature search, there is no specific data about Doppler findings in this disease. Case presentation Doppler findings of three cases of testicular microlithiasis during last two years in our institution are presented. Conclusions Although our hypothesis was to find increased Doppler...

  1. Efficient material characterization by means of the Doppler effect in microwaves

    OpenAIRE

    Pinchuk, Roman

    2007-01-01

    Das Thema dieser Dissertation ist die effiziente Materialcharakterisierung und Fehlerdetektion durch Nutzung des Dopplereffektes mittels Mikrowellen. Das erste Hauptziel der Arbeit ist die Entwicklung eines Prototyps eines Mikrowellen-Doppler-Systems im Bereich der zerstörungsfreien Prüfung. Das Doppler-System muss folgenden Voraussetzungen erfüllen: es sollte preisgünstig sein, leicht in industrielle Prozesse integrierbar sein und schnelle Messungen erlauben. Das Doppler-System muss die Soft...

  2. On the need for simultaneity between X-ray and radio observations in Doppler factor estimates

    OpenAIRE

    Liodakis, I.; Zezas, A.; Pavlidou, V.

    2015-01-01

    We use archival X-ray and radio VLBA data to calculate inverse Compton Doppler factors for four high-power radio, $\\gamma$-loud Flat Spectrum Radio Quasars frequently monitored by the F-GAMMA project. We explore the effect of the non-simultaneity between X-ray and radio observations by calculating Doppler factors for simultaneous and non-simultaneous observations. By comparing the newly re-calculated values from this work and archival values with variability Doppler factors,...

  3. Post-Newtonian Theory for Precision Doppler Measurements of Binary Star Orbits

    OpenAIRE

    Kopeikin, S. M.; Ozernoy, L. M.

    1998-01-01

    The determination of velocities of stars from precise Doppler measurements is described here using relativistic theory of astronomical reference frames so as to determine the Keplerian and post-Keplerian parameters of binary systems. We apply successive Lorentz transformations and the relativistic equation of light propagation to establish the exact treatment of Doppler effect in binary systems both in special and general relativity theories. As a result, the Doppler shift i...

  4. Maximum Likelihood Estimator For Doppler Parameter And Cramer Rao Bound In ZP-OFDM UWA Channel

    OpenAIRE

    Lyonnet, Bastien; Siclet, Cyrille; Brossier, Jean-Marc

    2010-01-01

    A Doppler estimation system using a maximum likelihood criterion is presented in the context of underwater acoustic communications between moving transmitter/receiver. We simulate the method for the estimation of the Doppler effect induced by an underwater acoustic channel (UWA) using Zero Padded-Orthogonal Frequency Division Multiplexing (ZP-OFDM). Among the wide range of physical processes that impact OFDM communications through the underwater environment, Doppler effect is an important cau...

  5. On the Use of Doppler Shift for Sea Surface Wind Retrieval From SAR

    OpenAIRE

    Mouche, Alexis; Collard, Fabrice; Chapron, Bertrand; Dagestad, Knut-Frode; Guitton, Gilles; Johannessen, Johnny A.; Kerbaol, Vincent; Hansen, Morten Wergeland

    2012-01-01

    The synthetic aperture radar (SAR) Doppler centroid has been used to estimate the scatter line-of-sight radar velocity. In weak to moderate ocean surface current environment, the SAR Doppler centroid is dominated by the directionality and strength of wave-induced ocean surface displacements. In this paper, we show how this sea state signature can be used to improve surface wind retrieval from SAR. Doppler shifts of C-band radar return signals from the ocean are thoroughly investigated by colo...

  6. Evaluation of color doppler ultrasonographic findings in cases with cervical lymphadenomegaly and histopathological correlation

    Directory of Open Access Journals (Sweden)

    Edip Hatipo?lu

    2008-01-01

    Full Text Available Objective: Our aim is to evaluate effectivity of color Doppler ultrasonography in differentiation of benign and malign lymph nodes in patients with cervical lymphadenomegaly, regarding histopathological results. Material and methods: Histopathological analysis was made to 20 patients with cervical lympadenomegaly after color Doppler ultrasonographic examinations. Results: Histopathologic results of 20 lymph nodes were: 7 reactive, 5 tuberculosis, 4 lymphoma, and 4 other malign lesions. Conclusion: In patients with cervical lymphadenomegaly, color Doppler ultrasonography was found to give additive information in differentiation of benign and malign lymph nodes with combined use of nodal vascularity pattern and color Doppler spectral analysis, to the other diagnostic modalities.

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

    Directory of Open Access Journals (Sweden)

    Jinsong Tang

    2013-07-01

    Full Text Available 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 presented to verify the performance.    

  8. Sub-Doppler Laser Cooling of Thulium Atoms in a Magneto-optical Trap

    OpenAIRE

    Sukachev, D.; Sokolov, A.; Chebakov, K.; Akimov, A.; Kanorsky, S.; Kolachevsky, N.; Sorokin, V

    2010-01-01

    We have experimentally studied sub-Doppler laser cooling in a magneto-optical trap for thulium atoms working at the wavelength of 410.6\\,nm. Without any dedicated molasses period of sub-Doppler cooling, the cloud of $3\\times 10^6$ atoms at the temperature of 25(5)\\,$\\mu$K was observed. The measured temperature is significantly lower than the Doppler limit of 240$\\mu$K for the cooling transition at 410.6\\,nm. High efficiency of the sub-Doppler cooling process is due to a near...

  9. Generation of void and Doppler reactivity feedback for application to BWR design (amendment No. 1)

    International Nuclear Information System (INIS)

    Information is presented under the following section headings: (1) Doppler reactivity and reactivity coefficients, (2) void reactivity and reactivity coefficients, and (3) design philosophy for plant transient analysis

  10. Acoustic Doppler Current Profiling near Myrtle Bend, June 3, 2013, Kootenai River near Bonners Ferry, ID

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Acoustic doppler current profiling (ADCP) data was collected to describe streamflow characteristics including total streamflow, velocity magnitude and secondary...

  11. Effects of testicular microlithiasis on Doppler parameters: report of three cases

    Directory of Open Access Journals (Sweden)

    Alkan Alpay

    2002-02-01

    Full Text Available Abstract Background Testicular microlithiasis is a rare, usually asymptomatic, non-progressive disease of the testes associated with various genetic anomalies, infertility and testicular tumors. According to our literature search, there is no specific data about Doppler findings in this disease. Case presentation Doppler findings of three cases of testicular microlithiasis during last two years in our institution are presented. Conclusions Although our hypothesis was to find increased Doppler parameters due to intratesticular arterial compression, our findings suggest that there are no Doppler findings specific to testicular microlithiasis.

  12. Non-Doppler Redshift and Dark Matter in the Coma Cluster

    OpenAIRE

    Zheng, Yi-Jia

    2013-01-01

    In 1929 Zwicky proposed a tired light theory to interpret the Hubble law (Hubble 1929). The key of the tired light theory is to interpret the observed redshift of galaxy as the non-Doppler effect. But the derivation of the dark matter in the Coma cluster proposed by Zwicky in 1933 was based on the interpretation that redshifts of galaxies were the Doppler effect, and the non-Doppler effect was not considered at all. However, if there is a reasonable non-Doppler effect and th...

  13. Frequency Diversity Technique for Space-borne Radar Doppler Measurements Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Doppler measurements from a rapid moving platform, such as spacecraft, or radars using fast scanning antennas have been especially challenging due to spectrum...

  14. Coherent Doppler Laser Radar: Technology Development and Applications

    Science.gov (United States)

    Kavaya, Michael J.; Arnold, James E. (Technical Monitor)

    2000-01-01

    NASA's Marshall Space Flight Center has been investigating, developing, and applying coherent Doppler laser radar technology for over 30 years. These efforts have included the first wind measurement in 1967, the first airborne flights in 1972, the first airborne wind field mapping in 1981, and the first measurement of hurricane eyewall winds in 1998. A parallel effort at MSFC since 1982 has been the study, modeling and technology development for a space-based global wind measurement system. These endeavors to date have resulted in compact, robust, eyesafe lidars at 2 micron wavelength based on solid-state laser technology; in a factor of 6 volume reduction in near diffraction limited, space-qualifiable telescopes; in sophisticated airborne scanners with full platform motion subtraction; in local oscillator lasers capable of rapid tuning of 25 GHz for removal of relative laser radar to target velocities over a 25 km/s range; in performance prediction theory and simulations that have been validated experimentally; and in extensive field campaign experience. We have also begun efforts to dramatically improve the fundamental photon efficiency of the laser radar, to demonstrate advanced lower mass laser radar telescopes and scanners; to develop laser and laser radar system alignment maintenance technologies; and to greatly improve the electrical efficiency, cooling technique, and robustness of the pulsed laser. This coherent Doppler laser radar technology is suitable for high resolution, high accuracy wind mapping; for aerosol and cloud measurement; for Differential Absorption Lidar (DIAL) measurements of atmospheric and trace gases; for hard target range and velocity measurement; and for hard target vibration spectra measurement. It is also suitable for a number of aircraft operations applications such as clear air turbulence (CAT) detection; dangerous wind shear (microburst) detection; airspeed, angle of attack, and sideslip measurement; and fuel savings through headwind minimization. In addition to the airborne and space platforms, a coherent Doppler laser radar system in an unmanned aerial vehicle (UAV) could provide battlefield weather and target identification.

  15. Colour doppler ultrasound assessment of the normal neonatal hip

    International Nuclear Information System (INIS)

    To determine the morphology and hemodynamic characteristics of the arterial vessels of the proximal femur according to specific anatomic regions in asymptomatic neonates in 2 pediatric-based health care institutions. Forty-three neonates (29 female, 14 male; age range, 2 d-3 mo; median age, 3 d) were enrolled in the study. Thirty-two (37%) of 86 hips were classified as Graf type IIA joints (mean alpha angle, 56.0o ± 2.7o), and 54 (63%) were classified as type I joints (mean alpha angle, 65.0o ± 4.6o). Colour and spectral Doppler imaging identified vessels running along the acetabular labrum, epiphyseal vessels, and femoral neck. We showed 4 different patterns of vascularity of the hips: radial, parallel, mixed radial-parallel, and indeterminate, however, they were not related to the hip maturity (P = .3, coronal plane; P = .62, transverse plane) or to the amount of colour pixels identified in each region (P = .35). The mean number of pixels in the ligamentum teres region was significantly higher than that in other regions of interest (P =.03). Except for the acetabular labrum arteries, Doppler spectrum waveforms of proximal femur arteries presented with low resistivity. There was a tendency towards females' acetabular arteries presenting with lower peak systolic velocities than males' acetabular arteries (P =.06). Colour Doppler spectrum waveforms and intensity of vascularity in normal neonatal hips differ according to the anatomic region under evaluation. This observation deserves further investigation on its role on the physiopathogenesis of neonatal hip disorders. (author)

  16. Colour doppler ultrasound assessment of the normal neonatal hip

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz-Neira, C.L. [Dept. of Diagnostic Imaging, Alberta Children' s Hospital, Calgary, Alberta (Canada)], E-mail: clara.ortiz@calgaryhealthregion.ca; Laffan, E.; Daneman, A. [Dept. of Diagnostic Imaging, The Hospital for Sick Children, Toronto, Ontario (Canada); Fong, K. [Dept. of Diagnostic Imaging, Mount Sinai Hospital, Toronto, Ontario (Canada); Roposch, A. [Dept. of Orthopedic Surgery, The Hospital for Sick Children, Toronto, Ontario (Canada); Great Ormond Street Hospital, Inst. of Child Health, Univ. College London, London (United Kingdom)

    2009-04-15

    To determine the morphology and hemodynamic characteristics of the arterial vessels of the proximal femur according to specific anatomic regions in asymptomatic neonates in 2 pediatric-based health care institutions. Forty-three neonates (29 female, 14 male; age range, 2 d-3 mo; median age, 3 d) were enrolled in the study. Thirty-two (37%) of 86 hips were classified as Graf type IIA joints (mean alpha angle, 56.0{sup o} {+-} 2.7{sup o}), and 54 (63%) were classified as type I joints (mean alpha angle, 65.0{sup o} {+-} 4.6{sup o}). Colour and spectral Doppler imaging identified vessels running along the acetabular labrum, epiphyseal vessels, and femoral neck. We showed 4 different patterns of vascularity of the hips: radial, parallel, mixed radial-parallel, and indeterminate, however, they were not related to the hip maturity (P = .3, coronal plane; P = .62, transverse plane) or to the amount of colour pixels identified in each region (P = .35). The mean number of pixels in the ligamentum teres region was significantly higher than that in other regions of interest (P =.03). Except for the acetabular labrum arteries, Doppler spectrum waveforms of proximal femur arteries presented with low resistivity. There was a tendency towards females' acetabular arteries presenting with lower peak systolic velocities than males' acetabular arteries (P =.06). Colour Doppler spectrum waveforms and intensity of vascularity in normal neonatal hips differ according to the anatomic region under evaluation. This observation deserves further investigation on its role on the physiopathogenesis of neonatal hip disorders. (author)

  17. From HARPS to CODEX: exploring the limits of Doppler measurements

    International Nuclear Information System (INIS)

    Only 3-6 years ago, the Doppler technique was believed to have reached its final limitations in measuring stellar velocities and finding extra-solar planets. The 3-4 m s-1 precision level achieved, at that time, by various teams, was certainly limited by instrumental performances, but also constrained, as believed by a part of the community, by intrinsic stellar limitations. The advent of HARPS drastically changed this view. The instrument demonstrated, through its recent discoveries, that stars more 'stable' than 1 m s-1 actually exist, and that their radial velocity (RV) can be measured at that level of precision. Short-term precision of 20 cm s-1 rms and long-term precision of the order of 30-60 cm s-1 rms have been actually achieved on real stars, showing that RVs still harbor a great potential, and not only in the domain of extra-solar planets. Indeed, HARPS inspired the CODEX at ELT experiment for the direct determination of the expansion of the Universe, measuring the Doppler shift of Ly-? forest lines as a function of time. This experiment calls for a Doppler precision as low as 1 cm s-1, which in turn inspires new possibilities in the domain of extra-solar planets. We will investigate the obstacles on the way to cm s-1 precision. The discussion presented here will be based on our experience with HARPS and what we consider to be the current limitations set by the instrument, telescope, atmosphere and star. Finally, we will also provide an outlook on possible improvements and expected performances, which will finally define new scientific opportunities

  18. High throughput spectrometer for fast localized Doppler measurements

    International Nuclear Information System (INIS)

    A new custom-built duo spectrometer has been commissioned for fast localized Doppler measurements of plasma ions in the Madison Symmetric Torus. The instrument combines very high optical throughput (transmission efficiency of 6% and etendue of 0.80 mm2 sr divided into two simultaneous measurements) with good resolution (?/??=5600). The design is a double grating variant of the Czerny-Turner layout and has been carefully optimized for fast (100 kHz) measurements of the C VI line at 343.4 nm. The instrument is currently being applied for high speed charge exchange recombination spectroscopy measurements

  19. Spinning disk calibration method and apparatus for laser Doppler velocimeter

    Science.gov (United States)

    Snyder, P. K. (inventor)

    1986-01-01

    A method and apparatus for calibrating laser Doppler velocimeters having one or more intersecting beam pairs are described. These velocimeters measure fluid velocity by observing the light scattered by particles in the fluid stream. Moving fluid particulates are simulated by fine taut wires that are radially mounted on a disk that is rotated at a known velocity. The laser beam intersection locus is first aimed at the very center of the disk and then the disk is translated so that the locus is swept by the rotating wires. The radial distance traversed is precisely measured so that the velocity of the wires (pseudo particles) may be calculated.

  20. Fatigue damage in superalloys determined using Doppler broadening positron annihilation

    Science.gov (United States)

    Hoeckelman, Donald; Leighly, H. P., Jr.

    1990-01-01

    Axial fatigue specimens of three superalloys, Inconel 718, Incoloy 903 and Haynes 188, were machined from solution-heat-treated material and artificially aged. They were subjected to cyclic loading for a selected number of cycles after which the S parameter was determined using Doppler broadening positron annihilation. Initially, the S parameter decreased, followed by a large increase and a subsequent decline leading to fracture. This has been interpreted as the removal of residual vacancies, the introduction of new defects by cyclic loading, and, finally, a clustering of the defects as microcracks which grow to cause failure.

  1. Short-time Fourier transform laser Doppler holography

    OpenAIRE

    Samson, Benjamin; Atlan, Michael

    2012-01-01

    We report a demonstration of laser Doppler holography at a sustained acquisition rate of 250 Hz on a 1 Megapixel complementary metal-oxide-semiconductor (CMOS) sensor array and image display at 10 Hz frame rate. The holograms are optically acquired in off-axis configuration, with a frequency-shifted reference beam. Wide-field imaging of optical fluctuations in a 250 Hz frequency band is achieved by turning time-domain samplings to the dual domain via short-time temporal Four...

  2. Approximation of the Doppler broadening function by Frobenius method

    International Nuclear Information System (INIS)

    An analytical approximation of the Doppler broadening function ?(x,?) is proposed. This approximation is based on the solution of the differential equation for ?(x,?) using the methods of Frobenius and the parameters variation. The analytical form derived for ?(x,?) in terms of elementary functions is very simple and precise. It can be useful for applications related to the treatment of nuclear resonances mainly for the calculations of multigroup parameters and self-protection factors of the resonances, being the last used to correct microscopic cross-sections measurements by the activation technique. (author)

  3. Wind Doppler lidar with 1.5 ?m fiber laser

    International Nuclear Information System (INIS)

    Compact Doppler lidar with monostatic receiving geometry has been developed and tested. Laser source of the lidar is continuous wave fiber laser ELD-1000 with 1.5 ?m wavelength and 1 W output. For distances up to 100 m the range of measurable wind velocities is 1.5 – 20 m/s. Results obtained show that performance conditions for the lidar corresponds to the visibility range up to 1 km. Sonic vibrations with small amplitudes (? 10 nm) of remote targets with diffuse reflection has been registered by this device at distances up to 60 m

  4. Hardening Doppler Global Velocimetry Systems for Large Wind Tunnel Applications

    Science.gov (United States)

    Meyers, James F.; Lee, Joseph W.; Fletcher, Mark T.; South, Bruce W.

    2004-01-01

    The development of Doppler Global Velocimetry from a laboratory curiosity to a wind tunnel instrumentation system is discussed. This development includes system advancements from a single velocity component to simultaneous three components, and from a steady state to instantaneous measurement. Improvements to system control and stability are discussed along with solutions to real world problems encountered in the wind tunnel. This on-going development program follows the cyclic evolution of understanding the physics of the technology, development of solutions, laboratory and wind tunnel testing, and reevaluation of the physics based on the test results.

  5. Sub-Doppler laser cooling and magnetic trapping of erbium

    International Nuclear Information System (INIS)

    We investigate cooling mechanisms in magneto-optically and magnetically trapped erbium. We find efficient sub-Doppler cooling in our trap, which can persist even in large magnetic fields due to the near degeneracy of two Lande g factors. Furthermore, a continuously loaded magnetic trap is demonstrated where we observe temperatures below 25 ?K. These favorable cooling and trapping properties suggest a number of scientific possibilities for rare-earth-metal atomic physics, including narrow linewidth laser cooling and spectroscopy, unique collision studies, and degenerate bosonic and fermionic gases with long-range magnetic dipole coupling

  6. Duplex Color Doppler Sonogram of the Orbital Diseases

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kil Woo; Kim, Chul Soo; Park, Won [Hallym University College of Medicine, Chuncheon (Korea, Republic of)

    1996-06-15

    To evaluate the clinical significance of the color Doppler ultrasound at glaucoma and diseases associated with intraocular hypertension, diabetic retinopathy, central retinal vessel occlusion, and other ocular diseases. We performed color Doppler ultrasound in 194 eyes of the 121 patients consisting of 62 normal, 46 primary open angle glaucoma (POAG), 27 ocular hypertension (OH), 14 normotensive glaucoma (NTG), 13 secondary glaucoma (SG), 13 proliferating diaetic retinopathy (PDR), 10 central retinal venous obstruction (CRVO),5 retinal detachment, and 4 others. The ophthalmic artery flow velocity was measured with the real time Doppler ultrasound using 5{approx}10 MHz linear probe. Sample volume size ranged from 1 to 1.5 mm. Angle corrections were selected below 60 degree. Results were statistically analyzed with paired t-test. Mean peak systolic velocities in the ophthalmic and central retinal arteries among 62 normal eyes were 36.4 {+-} 1 cm / sec and 5.9 {+-}0.3 cm / sec. Mean peak systolic velocities were 32.4 {+-} 2 cm / sec in the POAG, 35.9 {+-} 2 cm / sec in OH, 32.9 {+-}4 cm / sec in the NTG, 42.6 {+-} 3 cm / sec in the PDR, 36.4 {+-} 3 cm / sec in the SG, and 35.2 {+-} 3 in the CRVO. Innormal subjects, mean peak systolic velocity in ophthalmic artery was decreased with increasing age but no statistically significant difference was seen with Paired t-test. Comparing flow velocities between the normal and the glaucomatous lesions showed statistically no significant difference for mean peak systolic velocity. No significant difference was noted between right and left eyes but significant difference between male and female patients with Paired t-test. Mean resistive indices were 0.73 in ophthalmic artery and 0.65 in central retinal artery. Mean sample volume settings were 3.1 cm in depth for ophthalmic artery and 2.7 cm in depth for centralretinal artery. Color Doppler ultrasonogram of the orbit could diagnose the carotid cavernous fistula and the retinal detachment correctly. There was no significant difference between normal and glaucomatous lesions at the speed of the ophthalmic artery and the central retinal artery statistically. Normal values of the ophthalmic and central retinal arteries are considered to be very useful

  7. Duplex Color Doppler Sonogram of the Orbital Diseases

    International Nuclear Information System (INIS)

    To evaluate the clinical significance of the color Doppler ultrasound at glaucoma and diseases associated with intraocular hypertension, diabetic retinopathy, central retinal vessel occlusion, and other ocular diseases. We performed color Doppler ultrasound in 194 eyes of the 121 patients consisting of 62 normal, 46 primary open angle glaucoma (POAG), 27 ocular hypertension (OH), 14 normotensive glaucoma (NTG), 13 secondary glaucoma (SG), 13 proliferating diaetic retinopathy (PDR), 10 central retinal venous obstruction (CRVO),5 retinal detachment, and 4 others. The ophthalmic artery flow velocity was measured with the real time Doppler ultrasound using 5?10 MHz linear probe. Sample volume size ranged from 1 to 1.5 mm. Angle corrections were selected below 60 degree. Results were statistically analyzed with paired t-test. Mean peak systolic velocities in the ophthalmic and central retinal arteries among 62 normal eyes were 36.4 ± 1 cm / sec and 5.9 ±0.3 cm / sec. Mean peak systolic velocities were 32.4 ± 2 cm / sec in the POAG, 35.9 ± 2 cm / sec in OH, 32.9 ±4 cm / sec in the NTG, 42.6 ± 3 cm / sec in the PDR, 36.4 ± 3 cm / sec in the SG, and 35.2 ± 3 in the CRVO. Innormal subjects, mean peak systolic velocity in ophthalmic artery was decreased with increasing age but no statistically significant difference was seen with Paired t-test. Comparing flow velocities between the normal and the glaucomatous lesions showed statistically no significant difference for mean peak systolic velocity. No significant difference was noted between right and left eyes but significant difference between male and female patients with Paired t-test. Mean resistive indices were 0.73 in ophthalmic artery and 0.65 in central retinal artery. Mean sample volume settings were 3.1 cm in depth for ophthalmic artery and 2.7 cm in depth for centralretinal artery. Color Doppler ultrasonogram of the orbit could diagnose the carotid cavernous fistula and the retinal detachment correctly. There was no significant difference between normal and glaucomatous lesions at the speed of the ophthalmic artery and the central retinal artery statistically. Normal values of the ophthalmic and central retinal arteries are considered to be very useful

  8. [Blood pressure in neonates measured by Doppler ultrasound].

    Science.gov (United States)

    Lukanovi?, T; Fabeci?-Sabadi, V; Markicevi?, K; Kokos, Z

    1992-01-01

    In order to provide correct care for newborns it is necessary to determine the arterial pressure, since it is an important physiological indicator of body vitality. We measured blood pressure in 50 healthy, full term infants, born in Zagreb. All blood pressure readings were done by using a Doppler ultrasound. The 4 cm width cuff was used. The mean systolic pressure was 78.76 mmHg (SD +/- 8.6) and the diastolic one 35.78 mmHg (SD +/- 6). The level of systolic pressure was associated with body-mass (r = 0.371; p < 0.01), while sex had no effect on it. PMID:1343022

  9. Doppler Shift or Another Mass of a Nucleon?

    CERN Document Server

    Kopylov, A V

    1999-01-01

    The comparison of magnetic moments of neutron and proton reveals three possible stationary states of a nucleon: s-, p- and o-nucleon with different configurations and presumably different masses. Two of these nucleons may exist as the small impurities to the representative one. If so the frequency 1420405751.767 Hz of the hydrogen maser should be accompanied by the lines of weak intensity with a frequency shift proportional to the mass shift of a nucleon state. In radio astronomy the manifestation of this can be the presence of the corresponding "Doppler shifted" lines in the microwave spectrum of hydrogen.

  10. Renal Doppler ultrasound in patients with hypertension and metabolic syndrom.

    Science.gov (United States)

    Lubomirova, Mila; Djerassi, Regina; Kiperova, Boryana; Boyanov, Mihail; Christov, Vladimir

    2007-01-01

    Evaluation of the renal changes by conventional and Doppler ultrasound (US) was performed in patients with hypertension and obesity. 67 persons were examined and divided in 3 groups. Group I includes 27 patients--15 M and 12 F, average age 52+/-4.87 with well controlled diabetes mellitus type II and hypertension, Ccr.--139+/-1.31. Group II includes 20 patients--9 M and 11 F, average age 53+/-7 with well controlled hypertension without diabetes, with Ccr 128+/-7.8. Group III--20) pts. 8 F and 12 M, average age 54+/-5 with uncontrolled hypertension without diabetes, with Ccr 128+/-7.8. All examined pts. were with BMI>30 and hyperlipidemia--total cholesterol>6.5 mmol/l. Tests for microalbuminuria were negative in all 3 groups. In all three groups, using conventional US, the following parameters were detected by Aloca 4000 machine: renal (RV) and parenchyma (PV) volumes as well as Doppler parameters RI, PI, Vmax, Vmin, and Vmean. There were no significant differences between RV and PV of all examined groups: Group I--254+/-53, Group II--238+/-38, Group III--263+/-38, p=0.1. The strong correlation between renal volumes and BMI was found (Pearson's r 0.58). There were no significant differences between Vmax, Vmin, Vmean in all three groups. RI is normal <0.7 in all examined patients: Group I--0.63+/-0.06, Group II--0.61+/-0.02, Group III--0.66+/-0.03. RI in group III was significantly higher, p<0.05 compared to RI indices detected in other two groups but remains at normal levels. Intrarenal hemodynamics exhibited no difference in all examined groups. Analysis of the Doppler spectrum of the intrarenal arteries provides an accurate information about renal vascular changes but has no significant advantages in patients with hypertension and obesity with normal renal function and signs of hypertensive nephropathy "benign nephrosclerosis". Nevertheless Duplex Doppler Ultrasound is a noninvasive method which is an important part of the diagnostic algorithm in patients with diseases characterized by vascular involvement such as hypertension. PMID:18928166

  11. Optical spectroscopy and Doppler tomography of Cygnus X-2

    OpenAIRE

    Elebert, P.; Callanan, P.J.; Torres, M A P; M.R. Garcia

    2009-01-01

    We present phase resolved optical spectroscopy and Doppler tomography of V1341 Cygni, the optical counterpart to the neutron star low mass X-ray binary Cygnus X-2. We derive a radial velocity curve for the secondary star, finding a projected radial velocity semi-amplitude of K2 = 79 +/- 3 km/s, leading to a mass function of 0.51 +/- 0.06 Msun, ~30% lower than the previous estimate. We tentatively attribute the lower value of K2 (compared to that obtained by other authors) to...

  12. SIRHEN : a data reduction program for photonic Doppler velocimetry measurements.

    Energy Technology Data Exchange (ETDEWEB)

    Dolan, Daniel H., III; Ao, Tommy

    2010-06-01

    SIRHEN (Sandia InfraRed HEtrodyne aNalysis) is a program for reducing data from photonic Doppler velocimetry (PDV) measurements. SIRHEN uses the short-time Fourier transform method to extract velocity information. The program can be run in MATLAB (2008b or later) or as a Windows executable. This report describes the new Sandia InfraRed HEtrodyne aNalysis program (SIRHEN; pronounced 'siren') that has been developed for efficient and robust analysis of PDV data. The program was designed for easy use within Sandia's dynamic compression community.

  13. Multigroup Free-atom Doppler-broadening Approximation. Experiment

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-11-06

    The multigroup energy Doppler-broadening approximation agrees with continuous energy Dopplerbroadening generally to within ten percent for the total cross sections of 1H, 56Fe, and 235U at 250 lanl. Although this is probably not good enough for broadening from room temperature through the entire temperature range in production use, it is better than any interpolation scheme between temperatures proposed to date, and may be good enough for extrapolation from high temperatures. The method deserves further study since additional improvements are possible.

  14. Holographic laser Doppler imaging of pulsatile blood flow

    CERN Document Server

    Bencteux, Jeffrey; Kostas, Thomas; Bayat, Sam; Atlan, Michael

    2015-01-01

    We report on wide-field imaging of pulsatile motion induced by blood flow using heterodyne holographic interferometry on the thumb of a healthy volunteer, in real-time. Optical Doppler images were measured with green laser light by a frequency-shifted Mach-Zehnder interferometer in off-axis configuration. The recorded optical signal was linked to local instantaneous out-of-plane motion of the skin at velocities of a few hundreds of microns per second, and compared to blood pulse monitored by plethysmoraphy during an occlusion-reperfusion experiment.

  15. Synchronous ultrasonic Doppler imaging of magnetic microparticles in biological tissues

    International Nuclear Information System (INIS)

    We considered applicability of acoustic imaging technology for the detection of magnetic microparticles and nanoparticles inside soft biological tissues. Such particles are widely used for magnetically targeted drug delivery and magnetic hyperthermia. We developed a new method of ultrasonic synchronous tissue Doppler imaging with magnetic modulation for in vitro and in vivo detection and visualization of magnetic ultradisperse objects in soft tissues. Prototype hardware with appropriate software was produced and the method was successfully tested on magnetic microparticles injected into an excised pig liver.

  16. Laser-Doppler Imaging in the Detection of Peripheral Neuropathy

    OpenAIRE

    Illigens, Ben M. W.; Siepmann, Timo; Roofeh, Joe; Gibbons, Christopher H

    2013-01-01

    Small fiber neuropathy is common in a number of systemic diseases and is often challenging to diagnose. Laser-Doppler Imaging (LDI) is a test of small fiber neurovascular function that can quantify the integrity of the vasomotor C-fiber mediated axon-reflex, but no standardized method of analysis exists. We developed a novel LDI analysis technique and tested it in a human model of small fiber neuropathy. Eighteen healthy subjects (age 24±3 years) underwent LDI testing to assess the axon-media...

  17. Online Viscosity Measurement of Complex Solutions Using Ultrasound Doppler Velocimetry

    OpenAIRE

    KÖSEL?, Volkan; ZEYBEK, ?erife; ULUDAG, Yusuf

    2006-01-01

    A new method to measure the viscosity of non-Newtonian fluids over a wide range of shear rates in a short period of time is presented. The technique is based on the measurement of the velocity profile in a pipe flow using ultrasound Doppler velocimetry (UDV), which is a non-invasive method, and simultaneously determining the pressure drop. The velocity profile is used to obtain shear rate distribution, while the pressure drop is used to calculate the shear stress distribution. By ta...

  18. Using microwave Doppler radar in automated manufacturing applications

    Science.gov (United States)

    Smith, Gregory C.

    Since the beginning of the Industrial Revolution, manufacturers worldwide have used automation to improve productivity, gain market share, and meet growing or changing consumer demand for manufactured products. To stimulate further industrial productivity, manufacturers need more advanced automation technologies: "smart" part handling systems, automated assembly machines, CNC machine tools, and industrial robots that use new sensor technologies, advanced control systems, and intelligent decision-making algorithms to "see," "hear," "feel," and "think" at the levels needed to handle complex manufacturing tasks without human intervention. The investigator's dissertation offers three methods that could help make "smart" CNC machine tools and industrial robots possible: (1) A method for detecting acoustic emission using a microwave Doppler radar detector, (2) A method for detecting tool wear on a CNC lathe using a Doppler radar detector, and (3) An online non-contact method for detecting industrial robot position errors using a microwave Doppler radar motion detector. The dissertation studies indicate that microwave Doppler radar could be quite useful in automated manufacturing applications. In particular, the methods developed may help solve two difficult problems that hinder further progress in automating manufacturing processes: (1) Automating metal-cutting operations on CNC machine tools by providing a reliable non-contact method for detecting tool wear, and (2) Fully automating robotic manufacturing tasks by providing a reliable low-cost non-contact method for detecting on-line position errors. In addition, the studies offer a general non-contact method for detecting acoustic emission that may be useful in many other manufacturing and non-manufacturing areas, as well (e.g., monitoring and nondestructively testing structures, materials, manufacturing processes, and devices). By advancing the state of the art in manufacturing automation, the studies may help stimulate future growth in industrial productivity, which also promises to fuel economic growth and promote economic stability. The study also benefits the Department of Industrial Technology at Iowa State University and the field of Industrial Technology by contributing to the ongoing "smart" machine research program within the Department of Industrial Technology and by stimulating research into new sensor technologies within the University and within the field of Industrial Technology.

  19. Measurement of the Doppler effect in uranium-238

    International Nuclear Information System (INIS)

    The Doppler effect of 238U metal and 238U in U3O8 was studied by using beams of filtered neutrons at 24 +- 0.9 keV and 144 +- 12 keV from the University of Missouri Research Reactor (MURR) Facility. The Doppler effect is the broadening of the widths of the nuclear resonances in the total cross section due to the thermal motion of the nuclei. The effective average total cross sections (EATCS) for both kinds of samples were measured with good geometry transmission measurements as functions of sample thickness and temperature to show the Doppler effect. The temperature of the samples ranged from 38 to 1100 K. Temperature-related density effects were removed by simultaneously measuring the attenuation of gamma rays passing through the samples. The EATCS data as function of sample thickness at room temperature were fit with a nuclear cross section calculated from a ladder of resonances in the center-of-mass system. This ladder was generated from a set of synthesized nuclear parameters. The best fits to the cross sections when extrapolated to zero thickness, give 13.5 +- 0.2 b at 24 keV and 11.9 +- 0.2 b at 144 keV. The value at 24 keV agrees with the ENDF/B-IV, while the value at 144 keV is approx. 4% greater.An ideal gas model including an effective mass, M/sub eff/, and an effective temperature, T/sub eff/, was used to Doppler broaden the calculated nuclear cross sections. With this model, good agreement was obtained with the EATCS data for all sample thickness at all temperatures with an M/sub eff/ of 238 amu for the 238U metal and 400 amu for 238U in U3O8. The temperature dependence of t/sub eff/ was determined by calculating the total energy by use of Debye frequency theta/sub v/ distributions. In these calculations, the Debye temperatures, theta/sub D/, that provided the best fits were theta/sub D/ = 260 K for the metal and theta/sub D/ = 545 K for U3O8. 9 figures, 1 table

  20. Doppler Compensation by using of Segmented Match Filter

    OpenAIRE

    Nader Ghadimi; Mohammad Jabbariani; Hosein Khaleghi-Bizaki

    2008-01-01

    Match filter is one of the important parts of radar receiver. By using of Match Filter, the signal to noise ratio can be maximized so that the probability of detection is increased. Match Filter can be used as a pulse compression filter in radar receiver. Binary phase code is one of the pulse compression methods that, the compression can be down with a Match Filter in the receiver. Doppler effect is one of the problems that degrade the performance of Match Filter. In this paper, two methods “...

  1. Pioneer 10 Doppler data analysis: disentangling periodic and secular anomalies

    OpenAIRE

    Levy, A.; Christophe, B.; P. Berio; Metris, G.; Courty, J-M; Reynaud, S.

    2008-01-01

    This paper reports the results of an analysis of the Doppler tracking data of Pioneer probes which did show an anomalous behaviour. A software has been developed for the sake of performing a data analysis as independent as possible from that of J. Anderson et al. \\citep{anderson}, using the same data set. A first output of this new analysis is a confirmation of the existence of a secular anomaly with an amplitude about 0.8 nms$^{-2}$ compatible with that reported by Anderson...

  2. Corruption of radio metric Doppler due to solar plasma dynamics: S/X dual-frequency Doppler calibration for these effects

    Science.gov (United States)

    Winn, F. B.; Reinbold, S. R.; Yip, K. W.; Koch, R. E.; Lubeley, A.

    1975-01-01

    Doppler data from Mariner 6, 7, 9, and 10 and Pioneer 10 and 11 were discussed and the rms noise level for various sun-earth-probe angles were shown. The noise levels of both S- and X-band Doppler data for sun-earth-probe angles smaller than 20 deg were observed to be orders of magnitude greater than nominal. Such solar plasma-related Doppler degradation reduced the Mariner 10-Mercury 11 encounter navigation accuracy by nearly a factor of 10. Furthermore, this degradation was shown to be indirectly related to plasma dynamics and not a direct measure of the dynamics.

  3. An acoustic spanner and its associated rotational Doppler shift

    Energy Technology Data Exchange (ETDEWEB)

    Skeldon, K D; Wilson, C; Edgar, M; Padgett, M J [Department of Physics and Astronomy, University of Glasgow, Glasgow (United Kingdom)

    2008-01-15

    Light carries a spin angular momentum associated with its polarization and an orbital angular momentum arising from its phase cross-section. Sound, being a longitudinal wave, carries no spin component but can carry an orbital component of angular momentum when endowed with an appropriate phase structure. Here, we use a circular array of loudspeakers driven at a common angular frequency {omega}{sub s} but with an azimuthally changing phase delay to create a sound wave with helical phase fronts described by exp (il{theta}). Such waves are predicted to have an orbital angular momentum to energy ratio of l/{omega}{sub s}. We confirm this angular momentum content by measuring its transfer to a suspended 60 cm diameter acoustic absorbing tile. The resulting torque on the tile ({approx}6.1x10{sup -6} Nm) is measured from observation of the motion for various torsional pendulums. Furthermore, we confirm the helical nature of the acoustic beam by observing the rotational Doppler shift, which results from a rotation between source and observer of angular velocity {omega}{sub r}. We measure Doppler shifted frequencies of {omega}{sub s}{+-}l{omega}{sub r} depending on the direction of relative rotation.

  4. Intrinsic physical properties and Doppler boosting effects in LSI+61303

    CERN Document Server

    Massi, M

    2014-01-01

    Our aim is to show how variable Doppler boosting of an intrinsically variable jet can explain the long-term modulation of 1667 \\pm 8 days observed in the radio emission of LSI+61303. The physical scenario is that of a conical, magnetized plasma jet having a periodical (P1) increase of relativistic particles, Nrel, at a specific orbital phase, as predicted by accretion in the eccentric orbit of LSI+61303. Jet precession (P2) changes the angle, eta, between jet axis and line of sight, thereby inducing variable Doppler boosting. The problem is defined in spherical geometry, and the optical depth through the precessing jet is calculated by taking into account that the plasma is stratified along the jet axis. The synchrotron emission of such a jet was calculated and we fitted the resulting flux density Smodel(t) to the observed flux density obtained during a 6.5-year monitoring of LSI+61303 by the Green Bank radio interferometer. Our physical model for the system LSI+61303 is not only able to reproduce the long-te...

  5. The first Doppler images of the eclipsing binary SZ Piscium

    CERN Document Server

    Xiang, Yue; Cameron, A Collier; Barnes, J R; Zhang, Liyun

    2015-01-01

    We present the first Doppler images of the active eclipsing binary system SZ Psc, based on the high-resolution spectral data sets obtained in 2004 November and 2006 September--December. The least-squares deconvolution technique was applied to derive high signal-to-noise profiles from the observed spectra of SZ Psc. Absorption features contributed by a third component of the system were detected in the LSD profiles at all observed phases. We estimated the mass and period of the third component to be about $0.9 M_{\\odot}$ and $1283 \\pm 10$ d, respectively. After removing the contribution of the third body from the LSD profiles, we derived the surface maps of SZ Psc. The resulting Doppler images indicate significant starspot activities on the surface of the K subgiant component. The distributions of starspots are more complex than that revealed by previous photometric studies. The cooler K component exhibited pronounced high-latitude spots as well as numerous low- and intermediate-latitude spot groups during the...

  6. Multiplexed Photonic Doppler Velocimetry for Large Channel Count Experiments

    Science.gov (United States)

    Daykin, Edward; Burk, Martin; Gallegos, Cenobio; Pena, Michael; Perez, Carlos; Rutkowski, Araceli; Strand, Oliver; Holtkamp, David

    2015-06-01

    The Photonic Doppler Velocimeter (PDV) is routinely employed as a means of measuring surface velocities for shockwave experimentation. Scientists typically collect ~ 4 to 12 channels of PDV data and use extrapolation, assumptions and models to determine the velocities in regions of the experiment that were not observed directly. We have designed, built and applied a new optical velocimetry diagnostic - the Multiplexed Photonic Doppler Velocimeter (MPDV) - for use on shock physics experiments that requires a large number (~ 100) of spatial points to be measured. MPDV expands upon PDV measurement capabilities via frequency and time multiplexing. The MPDV is built using commercially available products. The MPDV uses the heterodyne method to multiplex four data channels in the frequency domain combined with fiber delays to multiplex an additional four channel data set in the time domain, all of which are recorded onto the same digitizer input. This means that each digitizer input records data from eight separate spatial points, so that a single 4-input digitizer may record a total of 32 channels of data. Motivation for development of a multiplexed PDV was driven by requirements for an economical, high channel count optical velocimetry system. We will present a survey of methods, components and trade-offs incorporated into this recent development in optical velocimetry.

  7. Raman processes in sub-Doppler laser cooling

    International Nuclear Information System (INIS)

    We have observed a new type of sub-Doppler laser cooling with neither polarization gradients nor magnetic fields. All known sub-Doppler laser cooling methods require one of these two to resdistribute the atomic population among the energy levels. This allows the irreversible processes of optical pumping vels. This allows the irreversible processes of optical pumping (OP) to manipulate the conservative force of light shifts (e.g. resonant exchange between the two beams comprising a standing wave) into a damping force. Our scheme employs stimulated Raman transitions between ground state hyperfine levels of Rb with a bichromatic standing wave, accompanied by a momentum change of ?p = 2?k. OP, with ?p = 1?k, creates a population imbalance allowing repetition of the Raman process. When the detuning of the light from Raman resonance ? is properly chosen, the net momentum exchange damps the atomic motion. Changing ? by only ?/6(1 MHz) replaces cooling by heating. This process separates the velocity selective Raman resonance and OP processes differently from others, and helps clarify the role of these different mechanisms

  8. Magnetic Doppler imaging of the chemically peculiar star HD 125248

    CERN Document Server

    Rusomarov, N; Ryabchikova, T; Ilyin, I

    2016-01-01

    Intermediate-mass, chemically peculiar stars with strong magnetic fields give us an excellent opportunity to study the topology of their surface magnetic fields and the interplay between magnetic geometries and abundance inhomogeneities in their atmospheres. We reconstruct detailed maps of the surface magnetic field and abundance distributions for the magnetic Ap star HD 125248. We performed the analysis based on phase-resolved, four Stokes parameter spectropolarimetric observations obtained with the HARPSpol instrument. These data were interpreted with the magnetic Doppler imaging technique. We improved the atmospheric parameters of the star, T_eff = 9850K +/- 250K and logg = 4.05 +/- 0.10. We performed detailed abundance analysis and discovered vertical stratification effects for the FeII and CrII ions. We computed LSD Stokes profiles and studied their behavior with rotational phase. We improved the rotational period of the star P_rot = 9.29558(6)d. Magnetic Doppler imaging of HD 125248 showed that its magn...

  9. SELENE mission: mathematical model for SST Doppler measurements

    Science.gov (United States)

    Ping, J.; Kono, Y.; Kawano, N.; Hanada, H.; Matsumoto, K.

    2001-09-01

    Japanese lunar exploration mission, SELENE, has been planned to be launched into space by using H II-a rocket in the Summer of 2004. This mission is composed of 3 subsatellites, a main lunar orbiter, a relay satellite and a free flying VLBI radio source. One of its main scientific objectives is the estimation of high order and degree spherical harmonic coefficients for the lunar gravity field. Different tracking methods will be employed in SELENE. The key tracking method is 4 way Satellite-to-Satellite Tracking (SST) technique. By this way, the tracking data can be obtained through the relay when the low altitude main orbiter is flying at the far-side of the Moon and can not be "seen" from the Earth. To success the historical tracking data, a complete coverage of Doppler tracking from an orbiter at sufficiently low altitude with high tracking accuracy can be obtained. The 4 way SST has various configurations. For SELENE, the SST tracking mode is introduced here, the mathematical relation between range rate and 4 way Doppler count number is established, and a data processing stream frame by using GEODYN II is suggested.

  10. Doppler shifted H Ly ? emission from Jupiter's aurora

    International Nuclear Information System (INIS)

    IUE observations of the aurora on Jupiter have been performed with high spectral resolution in a search for Doppler shifted H Ly ? emission produced through charge exchange by fast precipitating protons, as observed in the Earth's aurora. No emission has been observed corresponding to proton energies greater than 200 eV, placing a strict upper limit on the contribution of KeV - MeV protons to the production of Jupiter's aurora. However, a large fraction of the H Ly ? emission has appeared Doppler-shifted mainly toward the blue by roughly 50 km/sec, corresponding to a kinetic energy of 10-20 eV for a fast proton or H atom, and there are higher velocity wings on the line extending out to equivalent energies of 150-200 eV. The blue shift indicates motion up out of the atmosphere, and the authors suggest that the emission results from the in situ acceleration of ionospheric protons in Jupiter's auroral ionosphere by analogy to the ionospheric potentials observed in the Earth's auroral zones. These observations demonstrate that the acceleration of ionospheric plasma in an H2 atmosphere can lead to bright Ly ? emission, with implications for the production of the outer planet airglow emissions

  11. Magnetostriction measurement in thin films using laser Doppler vibrometry

    International Nuclear Information System (INIS)

    This paper reports the laser Doppler vibrometry based measurement of the magnetostriction in magnetic thin films. Using this method, the strain induced by an AC magnetic field in the polycrystalline cobalt ferrite and nickel ferrite thin films grown on silicon and platinized silicon substrates was measured under a DC magnetic bias. The experimental setup and the derivation of the magnetostriction constant from the experimentally measured deflection values are discussed. The magnetostriction values derived using force and bending moment balances were compared with that derived from an industry standard relationship. In addition, we corroborate our approach by comparing the values derived from bending theory calculations of magnetically induced torque to those from measurements using Vibrating Sample Magnetometer (VSM). At high DC magnetic field bias, the magnitude of magnetization calculated from the measured magnetostriction was found to match the measured magnetization by VSM. - Highlights: • Laser Doppler vibrometry based technique to measure magnetostriction in thin films. • Strain induced by an AC magnetic field under a DC magnetic bias. • Picometer level deflections in polycrystalline cobalt and nickel ferrite thin films

  12. Hypercholesterolemia and Myocardial function evaluated via Tissue Doppler Imaging

    Directory of Open Access Journals (Sweden)

    Kotaru Pavan

    2009-11-01

    Full Text Available Abstract Objective To establish a link between hypercholesterolemia and myocardial dysfunction. Background Heart failure is a complex disease involving changes in systolic and diastolic function. Newer echocardiographic imaging modalities may be able to detect discreet changes in myocardial function associated with hypercholesterolemia. Therefore we sought to establish a link between hypercholesterolemia and myocardial dysfunction with tissue Doppler imaging (TDI. Methods Twenty-seven rabbits were studied: 7 were fed normal chow (group 1 and 20 a high cholesterol diet (10 with ezetimibe, 1 mg/kg/day; group 2 and 10 without, group 3. Echocardiographic images were obtained under general anesthesia. Serum cholesterol levels were obtained at baseline, 3 and 6 months and myocardial cholesterol levels measured following euthanasia. Results Doppler measurements, including E/A, E'/A' and S' were significantly lower in group 3 compared to both groups 1 and 2 but no significant differences were noted in chamber sizes or ejection fraction among the groups. Average serum cholesterol was higher in group 3 compared to groups 1 and 2 respectively (495 ± 305 mg/dl vs. 114 ± 95 mg/dl and 87 ± 37 mg/dl; p 2 = 0.17 p = 0.04, r2 = 0.37 p = 0.001 and r2 = 0.24 p = 0.01. Conclusion Cholesterol load in the serum and myocardium was significantly associated with decreased systolic and diastolic function by TDI. Moreover, lipid lowering was protective.

  13. Observations of 2D Doppler backscattering on MAST

    CERN Document Server

    Thomas, D A; 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 an angular range of 6-24 degrees FWHM at 10-34.5 GHz. This capability is unique to SAMI and is an entirely novel way of conducting DBS experiments. In this paper the feasibility of conducting 2D DBS experiments is explored. Initial measurements of phenomena observed on conventional DBS experiments are presented; such as momentum injection from neutral beams and an abrupt change in power and turbulence velocity coinciding with the onset of H-mode. In addition, being able to carry out 2D DBS imaging allows a measurement of magnetic pitch an...

  14. On the Doppler effect for photons in rotating systems

    CERN Document Server

    Giuliani, Giuseppe

    2015-01-01

    The analysis of the Doppler effect for photons in rotating systems, studied using the M\\"ossbauer effect, confirms the general conclusions of a previous paper dedicated to experiments with photons emitted/absorbed by atoms/nuclei in inertial flight. The wave theory of light is so deeply rooted that it has been--and currently is--applied to describe phenomena in which the fundamental entities at work are discrete (photons). The fact that the wave theory of light can describe one aspect of these phenomena can not overshadow two issues: the corpuscular theory of light, firstly applied to the Doppler effect for photons by Schr\\"odinger in 1922, is by far more complete since it describes all the features of the studied phenomena; the wave theory can be used only when the number of photons at work is statistically significant. The disregard of basic methodological criteria may appear as a minor fault. However, the historical development of quantum physics shows that the predominance of the wave theory of radiation,...

  15. Sonographic and Doppler Sonographic Diagnosis of Posthemorrhagic Hydrocephalus.

    Science.gov (United States)

    Deeg, K H

    2015-08-01

    Severe intracranial hemorrhages occur especially in very immature premature infants born with a gestational age under 28 weeks of gestation and a birth weight below 1000?g. Severe hemorrhages are often complicated by a post-hemorrhagic hydrocephalus (PHH). PHH can be caused by a blockage of the cerebro-spinal fluid pathways or by obliterative arachnoiditis of the posterior cranial fossa. Cerebral sonography can differentiate between both entities. In cases of obstruction of the cerebro-spinal fluid circulation the parts of the ventricular system infront of the obstruction are dilated. Color coded Doppler sonography can display the patency or obstruction of the physiologic constrictions of the ventricular system. Increased intracranial pressure can noninvasively be detected by spectral Doppler: The increase of the peak systolic flow velocity in the intracranial section of the internal carotid artery in comparison with the extra-cranial part is an early indication of a raised intracranial pressure. The decrease of the end-diastolic flow velocity during fontanel compression is indicative of abolished cranial compliance and increased intracranial pressure. In the case of raised intracranial pressure diastolic amplitudes and end-diastolic flow velocities are decreased and the resistive-indices are increased. PMID:25607627

  16. Optical spectroscopy and Doppler tomography of Cygnus X-2

    CERN Document Server

    Elebert, P; Torres, M A P; García, M R

    2009-01-01

    We present phase resolved optical spectroscopy and Doppler tomography of V1341 Cygni, the optical counterpart to the neutron star low mass X-ray binary Cygnus X-2. We derive a radial velocity curve for the secondary star, finding a projected radial velocity semi-amplitude of K2 = 79 +/- 3 km/s, leading to a mass function of 0.51 +/- 0.06 Msun, ~30% lower than the previous estimate. We tentatively attribute the lower value of K2 (compared to that obtained by other authors) to variations in the X-ray irradiation of the secondary star at different epochs of observations. The limited phase coverage and/or longer timebase of previous observations may also contribute to the difference in K2. Our value for the mass function implies a primary mass of 1.5 +/- 0.3 Msun, somewhat lower than previous dynamical estimates, but consistent with the value found by analysis of type-I X-ray bursts from this system. Our Doppler tomography of the broad He II 4686 line reveals that most of the emission from this line is produced o...

  17. Magnetostriction measurement in thin films using laser Doppler vibrometry

    Energy Technology Data Exchange (ETDEWEB)

    Varghese, Ronnie, E-mail: ronniev@vt.edu [Center for Energy Harvesting Materials and Systems (CEHMS), Bio-Inspired Materials and Devices Laboratory (BMDL), Virginia Tech, Blacksburg, VA 24061 (United States); Viswan, Ravindranath [Materials Science and Engineering Department, Virginia Tech, Blacksburg, VA 24061 (United States); Joshi, Keyur [Center for Energy Harvesting Materials and Systems (CEHMS), Bio-Inspired Materials and Devices Laboratory (BMDL), Virginia Tech, Blacksburg, VA 24061 (United States); Seifikar, Safoura [Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695 (United States); Zhou, Yuan [Center for Energy Harvesting Materials and Systems (CEHMS), Bio-Inspired Materials and Devices Laboratory (BMDL), Virginia Tech, Blacksburg, VA 24061 (United States); Schwartz, Justin [Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695 (United States); Priya, Shashank [Center for Energy Harvesting Materials and Systems (CEHMS), Bio-Inspired Materials and Devices Laboratory (BMDL), Virginia Tech, Blacksburg, VA 24061 (United States)

    2014-08-01

    This paper reports the laser Doppler vibrometry based measurement of the magnetostriction in magnetic thin films. Using this method, the strain induced by an AC magnetic field in the polycrystalline cobalt ferrite and nickel ferrite thin films grown on silicon and platinized silicon substrates was measured under a DC magnetic bias. The experimental setup and the derivation of the magnetostriction constant from the experimentally measured deflection values are discussed. The magnetostriction values derived using force and bending moment balances were compared with that derived from an industry standard relationship. In addition, we corroborate our approach by comparing the values derived from bending theory calculations of magnetically induced torque to those from measurements using Vibrating Sample Magnetometer (VSM). At high DC magnetic field bias, the magnitude of magnetization calculated from the measured magnetostriction was found to match the measured magnetization by VSM. - Highlights: • Laser Doppler vibrometry based technique to measure magnetostriction in thin films. • Strain induced by an AC magnetic field under a DC magnetic bias. • Picometer level deflections in polycrystalline cobalt and nickel ferrite thin films.

  18. Ecocardiografia Doppler em cães neonatos / Echodoppler cardiography in newborn dogs

    Scientific Electronic Library Online (English)

    R.O., Alves; R.B., Araújo; E.F., Silva; F.A.B., Viana; J.L.B., Pena.

    2001-08-01

    Full Text Available Utilizaram-se 10 cães neonatos (cinco machos e cinco fêmeas), obtidos a partir de cinco ninhadas (um casal de cada) com o objetivo de estabelecer o perfil ecodopplercardiográfico normal durante a fase neonatal (de um até 30 dias). Por meio do Doppler pulsado foram mensurados os picos de velocidade d [...] os fluxos sangüíneos através das valvas mitral, tricúspide, aórtica e pulmonar. Observou-se correlação positiva de todas as mensurações com o peso corporal e a idade dos neonatos de ambos os sexos. Não houve diferenças significativas no padrão de velocidade dos fluxos sangüíneos estudados entre machos e fêmeas durante a fase neonatal. Abstract in english Ten healthy puppies (five males and five females) were used to establish the regular echodopplercardiography profile during the neonatal period (from one to 30 days) utilizing Doppler (pulsed-wave and color flow). Mitral, tricuspid, aortic and pulmonary blood flows were measured. Positive correlatio [...] ns of all the measures, with body weight and age of the puppies for both sexes were observed. No differences in the cardiac development between male and female during the neonatal phase were observed.

  19. Doppler effects on velocity spectra observed by MST radars

    Science.gov (United States)

    Scheffler, A. O.; Liu, C. H.

    1986-01-01

    Recently, wind data from mesophere-stratosphere-troposphere (MST) radars have been used to study the spectra of gravity waves in the atmosphere (Scheffler and Liu, 1985; VanZandt et al., 1985). Since MST radar measures the line-of-sight Doppler velocities, it senses the components of the wave-associated velocities along its beam directions. These components are related through the polarization relations which depend on the frequency and wave number of the wave. Therfore, the radar-observed velocity spectrum will be different from the original gravity-wave spectrum. Their relationship depends on the frequency and wave number of the wave as well as the propagation geometry. This relation can be used to interpret the observed data. It can also be used to test the assumption of gravity-wave spectrum (Scheffler and Liu, 1985). In deriving this relation, the background atmosphere has been assumed to be motionless. Obviously, the Doppler shift due to the background wind will change the shape of the gravity-wave power spectrum as well as its relation with the radar-observed spectrum. Here, researcher's investigate these changes.

  20. A Fisheye Lens as a Photonic Doppler Velocimetry Probe

    Energy Technology Data Exchange (ETDEWEB)

    Frogget, B C; Cox, B C; DeVore, D O; Esquibel, D L; Frayer, D K; Furlanetto, M R; Holtkamp, D B; Kaufman, M I; Malone, R M

    2012-09-01

    A new fisheye lens design is used as a miniature probe to measure the velocity distribution of an imploding surface along many lines of sight. Laser light, directed and scattered back along each beam on the surface, is Doppler shifted by the moving surface and collected into the launching fiber. The received light is mixed with reference laser light in each optical fiber in a technique called photonic Doppler velocimetry, providing a continuous time record. An array of single-mode optical fibers sends laser light through the fisheye lens. The lens consists of an index-matching positive element, two positive doublet groups, and two negative singlet elements. The optical design minimizes beam diameters, physical size, and back reflections for excellent signal collection. The fiber array projected through the fisheye lens provides many measurement points of surface coverage over a hemisphere with very little crosstalk. The probe measures surface movement with only a small encroachment into the center of the cavity. The fiber array is coupled to the index-matching element using index-matching gel. The array is bonded and sealed into a blast tube for ease of assembly and focusing. This configuration also allows the fiber array to be flat polished at a common object plane. In areas where increased measurement point density is desired, the fibers can be close packed. To further increase surface density coverage, smaller-diameter cladding optical fibers may be used.

  1. Estudio de la aorta abdominal mediante doppler espectral pulsado en perros Vascular study of abdominal aorta using doppler duplex ultrasonography in dogs

    OpenAIRE

    N Miño; L Espino; M Suárez; G. Santamarina; A. Barriero

    2004-01-01

    Para poder realizar un diagnóstico correcto de la aorta abdominal mediante Doppler duplex vascular es necesario un buen conocimiento del espectro Doppler característico y de los resultados obtenidos respecto de los parámetros de flujo. Para ello, se usaron diez perros adultos, cinco machos y cinco hembras, de la raza Beagle, sin someterlos a tranquilización previa. Se tomaron cinco medidas de cada parámetro en estudio, buscando un ángulo inferior a 45º y un espectro obtenido que se ajustara a...

  2. Velocimetria Doppler no período neonatal em recém-nascidos a termo pequenos para idade gestacional Neonatal Doppler velocimetry in full term small-for-gestational age newborns

    OpenAIRE

    Iracema Augusta Carvalho Cortez Muniz; Abimael Aranha Netto; Vanda Maria Gimenes Gonçalves

    2003-01-01

    Este estudo teve como objetivo avaliar o fluxo sanguíneo cerebral em recém-nascidos a termo pequenos para idade gestacional, utilizando ultra-sonografia Doppler craniana ao nascimento. O estudo foi desenvolvido no CAISM/UNICAMP (Centro de Saúde Terciário para Mulheres). Foram selecionados sessenta recém-nascidos e divididos em 2 grupos: 36 adequados para idade gestacional (AIG) e 24 pequenos para idade gestacional (PIG). Foi realizada a avaliação de ultra-sonografia Doppler craniana nos grupo...

  3. Absolute Retinal Blood Flow Measurement With a Dual-Beam Doppler Optical Coherence Tomography

    OpenAIRE

    Dai, Cuixia; Liu, Xiaojing; Zhang, Hao F.; Puliafito, Carmen A.; Jiao, Shuliang

    2013-01-01

    A novel dual-beam Doppler OCT technique was developed for simultaneous in vivo measurement of the Doppler angle and, thus, the absolute retinal blood velocity and the retinal flow rate, without the influence of motion artifacts. The technique was successfully tested on humans.

  4. Predicted Doppler shifts induced by ocean surface wave displacements using asymptotic electromagnetic wave scattering theories

    OpenAIRE

    Mouche, Alexis; Chapron, Bertrand; Reul, Nicolas; F. Collard

    2008-01-01

    Sea surface motions can produce different measured Doppler shifts with respect to instrumental configurations (incidence angle, electromagnetic wavelength, polarization). Under Gaussian statistics for the sea surface elevation and in the general framework of asymptotic theories for ocean surface electromagnetic wave scattering, Doppler shifts can be predicted. The small-slope, Kirchhoff, local curvature and resonant curvature approximations are compared in the backscatter configuration. Predi...

  5. Correlation between Spectral Index and Doppler Factor for a Sample of Fermi Blazars

    Indian Academy of Sciences (India)

    J. Tao; J. H. Fan; H. J. Pan; D. X. Wu; S. H. Li

    2014-09-01

    Relativistic beaming effect is important for blazars. In a very recent work, -ray Doppler factors were calculated for a sample of Fermi blazars (Fan et al. 2013). In this work, we investigated the correlation between the Doppler factor and the effective spectral index, 4OX, and found an anticorrelation between them.

  6. Evaluation of gastrointestinal activity patterns in healthy horses using B mode and Doppler ultrasonography

    OpenAIRE

    Mitchell, Colin F.; Malone, Erin D.; Sage, Abby M.; Niksich, Katie

    2005-01-01

    Healthy adult horses were examined by using transabdominal ultrasonography to quantitatively and qualitatively evaluate activity of the jejunum, cecum, and colon with B mode and Doppler techniques. Doppler ultrasound was used to assess jejunal peristaltic activity. Examinations were performed on multiple occasions under imposed colic evaluation conditions, including fasting, nasogastric intubation, and xylazine sedation.

  7. Concept for automatic Doppler compensation in two-way communication systems

    Science.gov (United States)

    Muller, R. M.

    1968-01-01

    Automatic Frequency Control system compensates for Doppler shift in two-way communication systems where one or both stations are moving. This automatic correction can be applied to the reply link to elimate frequency search for the reply or an excessive bandwidth to accommodate the Doppler.

  8. Transesophageal tissue Doppler echocardiography for evaluation of myocardial function during aortic valve replacement

    DEFF Research Database (Denmark)

    Norrild, Kathrine; Pedersen, Troels Fogh; Sloth, Erik

    2007-01-01

    Tissue Doppler imaging is an evolving ultrasound technology that, compared with traditional echocardiography, promises reduced subjectivity in the assessment of myocardial performance and contributes new information on myocardial function. The aim of this study was to evaluate the feasibility of transesophageal tissue Doppler imaging in the setting of aortic valve replacement.

  9. Population statistics of beamed sources - II. Evaluation of Doppler factor estimates

    Science.gov (United States)

    Liodakis, I.; Pavlidou, V.

    2015-12-01

    In a companion paper we presented a statistical model for the blazar population, consisting of distributions for the unbeamed radio luminosity function and the Lorentz factor distribution of each of the BL Lac and Flat Spectrum Radio Quasar (FSRQ) classes. Our model has been optimized so that it reproduces the MOJAVE (Monitoring Of Jets in Active galactic nuclei with VLBA Experiments) distributions of apparent speeds and redshifts when the appropriate flux limit is applied and a uniform distribution of jet viewing angles is assumed for the population. Here we use this model to predict the Doppler factor distribution for various flux-limited samples for which Doppler factors have been estimated in a variety of ways (equipartition, variability + equipartition, inverse Compton dominance) on a blazar-by-blazar basis. By comparing the simulated and data-estimated Doppler factor distributions in each case, we evaluate the different methods of estimating blazar Doppler factors. We find that the variability Doppler factors assuming equipartition are the ones in the best agreement with our statistical model, whereas the inverse Compton Doppler factor method is only suitable for FSRQs. In the case of variability Doppler factors, we find that while random errors are relatively low (˜30 per cent), uncertainties are dominated by systematic effects. In the case of inverse Compton Doppler factors, random errors appear to dominate, but are significantly larger (˜60 per cent).

  10. Effect of interposed skin at Doppler flow estimation at 5 and 10 MHz

    International Nuclear Information System (INIS)

    Flow measurements with high ultrasound frequencies (Doppler technique) can be used at quantitative estimations of flow. A calibrator for Doppler equipments is presented. The effect of skin as interposed material with 10 MHz and 5 MHz is discussed as are limitations in the apparatus itself especially when using 10 MHz ultrasound. (Auth.)

  11. Strain rate derived from color Doppler myocardial imaging for assessment of fetal cardiac function

    DEFF Research Database (Denmark)

    Larsen, L U; Petersen, O B; Norrild, K; Sorensen, K; Uldbjerg, Niels; Sloth, E

    2006-01-01

    Color Doppler myocardial imaging (CDMI) is a new multigated method that allows direct analysis of myocardial motion. It is superior to pulsed-wave tissue Doppler in its ability to generate new and important indices of myocardial function such as strain, strain rate and tissue tracking. The purpose of this study was to assess the feasibility of CDMI in the fetal heart.

  12. Algunas aplicaciones del Doppler transcraneal no habituales en las unidades de cuidados intensivos / Some uncommon applications of transcranial Doppler in the intensive care unit

    Scientific Electronic Library Online (English)

    J.A., Álvarez-Fernández; R., Pérez-Quintero.

    2009-03-01

    Full Text Available Se presenta el caso de una mujer de 64 años con shock por colitis isquémica en relación con embolia paradójica a través de un foramen oval permeable. Se comentan algunas utilidades del Doppler transcraneal empleadas en este caso que podrían tener interés habitual en cuidados intensivos e intermedios [...] . Éstas incluyen el análisis de la distribución regional del flujo sanguíneo cerebral, la monitorización arterial intracraneal para detección de microembolias espontáneas o la inyección de microburbujas para detección de cortocircuito derecha-izquierda. Se destaca el valor añadido aportado por la incorporación del Doppler modo M a la ultrasonografía Doppler transcraneal. Abstract in english We present the case of a 64-year old woman with shock related to ischemic colitis associated with paradoxical embolism through a foramen ovale. Some utilities of transcranial Doppler ultra-sonography applied in this case that could have an usual interest in intensive and intermediate care are discus [...] sed. These include analysis of the regional distribution of cerebral blood flow, intracranial arterial continuous monitoring for detection of spontaneous microembolisms and injection of microbubbles to detect right to left shunts. The added value of using power M-mode Doppler in transcranial Doppler evaluations is highlighted.

  13. Algunas aplicaciones del Doppler transcraneal no habituales en las unidades de cuidados intensivos Some uncommon applications of transcranial Doppler in the intensive care unit

    Directory of Open Access Journals (Sweden)

    J.A. Álvarez-Fernández

    2009-03-01

    Full Text Available Se presenta el caso de una mujer de 64 años con shock por colitis isquémica en relación con embolia paradójica a través de un foramen oval permeable. Se comentan algunas utilidades del Doppler transcraneal empleadas en este caso que podrían tener interés habitual en cuidados intensivos e intermedios. Éstas incluyen el análisis de la distribución regional del flujo sanguíneo cerebral, la monitorización arterial intracraneal para detección de microembolias espontáneas o la inyección de microburbujas para detección de cortocircuito derecha-izquierda. Se destaca el valor añadido aportado por la incorporación del Doppler modo M a la ultrasonografía Doppler transcraneal.We present the case of a 64-year old woman with shock related to ischemic colitis associated with paradoxical embolism through a foramen ovale. Some utilities of transcranial Doppler ultra-sonography applied in this case that could have an usual interest in intensive and intermediate care are discussed. These include analysis of the regional distribution of cerebral blood flow, intracranial arterial continuous monitoring for detection of spontaneous microembolisms and injection of microbubbles to detect right to left shunts. The added value of using power M-mode Doppler in transcranial Doppler evaluations is highlighted.

  14. Valor diagnóstico de la ecografía Doppler transcraneal en oftalmología / Diagnostic value of transcranial Doppler ultrasound in ophthalmology

    Scientific Electronic Library Online (English)

    Mayelín, Navarro Scott; Alina, Recasens Cáceres; Ana, Lamas Ávila.

    2011-04-01

    Full Text Available La ecografía Doppler transcraneal oftálmica es el estudio no invasivo de los vasos oculares intracraneales, útil no solo como prueba de exploración selectiva, sino también como instrumento para valorar la extensión y gravedad de las enfermedades arteriales. Sus usos en el campo oftalmológico son múl [...] tiples, aunque en la mayoría de los casos se indica para precisar los cambios del flujo sanguíneo en pacientes diabéticos, con retinopatía o sin ella. Dada la importancia que en los últimos años han ido adquiriendo las alteraciones vasculares en la génesis de algunas afecciones oculares, particularmente en el glaucoma, se decidió revisar la bibliografía médica sobre esa técnica de ultrasonidos para destacar su valor radiodiagnóstico en oftalmología. Abstract in english Transcranial Doppler ultrasound in ophthalmology is a noninvasive study of intracranial ocular vessels, useful not only as a selective scanning test, but also as a tool to evaluate the extent and severity of arterial disease. Its uses in ophthalmology are numerous, although in most cases it is indic [...] ated to specify the changes of the blood flow in diabetic patients with retinopathy o without it. Given the importance that in recent years vascular abnormalities have acquired in the genesis of some ocular conditions, particularly in glaucoma, it is decided to review the literature on that ultrasonic technique to highlight its radiodiagnostic value in ophthalmology.

  15. Null vector fields in spaces with affine connections and metrics. Doppler's effect, Hubble's effect, and aberration's effect

    OpenAIRE

    Manoff, Sawa

    2003-01-01

    The notion of null (isotropic) vector field is considered in spaces with affine connections and metrics as models of space or space-time. On its basis the propagation of signals in space-time is considered. The Doppler effect is generalized for these types of spaces. The notions of standard (longitudinal) Doppler effect and transversal Doppler effect are introduced. On their grounds, the Hubble effect and the aberration effect appear as Doppler effects with explicit forms of...

  16. Transthoracic Doppler echocardiography to predict optimal tube pulsing window for coronary artery CT angiography

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Gang, E-mail: cjr.sungang@vip.163.com [Department of Medical Imaging, Jinan Military General Hospital, No. 25, Shifan Road, Jinan, Shandong Province 250031 (China); Li, Min, E-mail: limin22000@yahoo.com.cn [Department of Medical Imaging, Jinan Military General Hospital, No. 25, Shifan Road, Jinan, Shandong Province 250031 (China); Jiang, Xiang-sen, E-mail: jiangxiangsen123@126.com [Department of Medical Imaging, Jinan Military General Hospital, No. 25, Shifan Road, Jinan, Shandong Province 250031 (China); Li, Li, E-mail: leely1976@yahoo.com.cn [Department of Medical Imaging, Jinan Military General Hospital, No. 25, Shifan Road, Jinan, Shandong Province 250031 (China); Peng, Zhao-hui, E-mail: zhaohuipeng_R@163.com [Department of Medical Imaging, Jinan Military General Hospital, No. 25, Shifan Road, Jinan, Shandong Province 250031 (China); Mu, Nan-nan, E-mail: munannan22000@sohu.com [Department of Medical Imaging, Jinan Military General Hospital, No. 25, Shifan Road, Jinan, Shandong Province 250031 (China)

    2012-09-15

    Rationale and objective: To evaluate the feasibility of transthoracic Doppler echocardiography to determine the optimal pulsing windows for CT coronary angiography to narrow the pulsing windows further, especially in higher heart rate. Materials and methods: Doppler was performed on 135 patients before CT scanning. For Doppler, the intervals with minimal motion were evaluated during both systole and diastole integrating electrocardiogram (ECG) intervals. For CT scanning, the retrospective ECG-gating was applied and the optimal reconstruction intervals were determined. The accuracy of Doppler analysis to predict the optimal reconstruction intervals was tested. The predicted length of pulsing windows was compared between Doppler analysis and traditional prospective ECG-gating protocol (heart rate ? 65 bpm, 60–76%; 66–79 bpm, 30–77%; ?80 bpm, 31–47%). Results: According to Doppler analysis, the mean length of intervals with minimal motion in systole was 106.4 ± 39.2 ms and 125.2 ± 92.0 ms in diastole. When the intervals with minimal motion during diastole > 90 ms, the optimal reconstruction intervals were located at diastole; otherwise, at systole (P < 0.001). The optimal reconstruction intervals in 93.8% (132/135) patients could be predicted accurately by Doppler analysis. If the optimal reconstruction intervals predicted by Doppler were applied as the exposure windows, the mean length of pulsing windows should has been 105.2 ± 69.4 ms (range: 26.9–510.3 ms), which was significantly shorter than that of traditional prospective ECG-gating protocol (232.0 ± 120.2 ms, range: 93.2–427.3 ms, P < 0.001). Conclusion: Doppler can help detecting the optimal pulsing windows accurately. Prospective ECG-gating incorporating Doppler analysis may narrow pulsing windows significantly while maintaining image quality.

  17. Magnetic Compensation for Second-Order Doppler Shift in LITS

    Science.gov (United States)

    Burt, Eric; Tjoelker, Robert

    2008-01-01

    The uncertainty in the frequency of a linear-ion-trap frequency standard (LITS) can be reduced substantially by use of a very small magnetic inhomogeneity tailored to compensate for the residual second-order Doppler shift. An effect associated with the relativistic time dilatation, one cause of the second-order Doppler shift, is ion motion that is attributable to the trapping radio-frequency (RF)electromagnetic field used to trap ions. The second-order Doppler shift is reduced by using a multi-pole trap; however it is still the largest source of systematic frequency shift in the latest generation of LITSs, which are among the most stable clocks in the world. The present compensation scheme reduces the frequency instability of the affected LITS to about a tenth of its previous value. The basic principles of prior generation LITSs were discussed in several prior NASA Tech Briefs articles. Below are recapitulated only those items of basic information necessary to place the present development in context. A LITS includes a microwave local oscillator, the frequency of which is stabilized by comparison with the frequency of the ground state hyperfine transition of 199Hg+ ions. The comparison involves a combination of optical and microwave excitation and interrogation of the ions in a linear ion trap in the presence of a nominally uniform magnetic field. In the current version of the LITS, there are two connected traps (see figure): (1) a quadrupole trap wherein the optical excitation and measurement take place and (2) a 12-pole trap (denoted the resonance trap), wherein the microwave interrogation takes place. The ions are initially loaded into the quadrupole trap and are thereafter shuttled between the two traps. Shuttling ions into the resonance trap allows sensitive microwave interrogation to take place well away from loading interference. The axial magnetic field for the resonance trap is generated by an electric current in a finely wound wire coil surrounded by magnetic shields. In the quadrupole and 12-pole traps, the potentials are produced by RF voltages applied to even numbers (4 and 12, respectively) of parallel rods equally spaced around a circle. The polarity of the voltage on each rod is opposite that of the voltage on the adjacent rod. As a result, the amplitude of the RF trapping field is zero along the centerline and increases, with radius, to a maximum value near the rods.

  18. Doppler Sodar as a remote sensing tool for environmental monitoring

    International Nuclear Information System (INIS)

    The environmental and atmospheric parameters are of utmost importance for the survival of human beings. The atmosphere in which we live has a dominant role to play in our life and any adverse change in its structure has a potential to create catastrophic effect The most important atmospheric parameters are temperature, pressure, humidity, precipitation and winds. Wide range of instruments are used for monitoring these meteorological parameters on regular basis. The observations could be taken up at various heights starting from surface level up to 100 Kms SAMEER has been working in the area of atmospheric instrumentation since past three decades. The class of instruments used to make measurements with higher resolution in space and time are clear air Doppler radars which are popularly known as Wind Profilers. It is possible to measure the vertical profile of winds on continuous basis with higher accuracy with these instruments. These profilers have numerous applications in meteorology, atmospheric research, environmental and pollution monitoring. Technology of acoustic sounders was developed for probing the boundary layer of the atmosphere. These sounders known as Doppler Sodars are used to remotely measure wind speed, wind direction and turbulence of the atmospheric boundary Layer. The data obtained though this instrument is used for assessment of environmental impacts at nuclear and thermal power plants, atmospheric dispersion studies and emergency response wind monitoring. Large scale industrial plants as well as Nuclear/Thermal Power plants have fallout of smoke, toxic gases, particulate matter and hazardous chemicals. In normal condition the pollutant are dispersed due to the turbulence in atmosphere. However in certain calm conditions when the atmosphere stable the pollutants are trapped and their concentration go beyond permissible limit posing major health hazard. It is very important to know the atmospheric dynamics near the high risk installations and monitor the air quality. Diffusion and transport of pollutants are required to be assessed so that the effluent concentration does not increase beyond permissible limits. Doppler Sodars are used for evaluating main atmospheric variables which affect the boundary layer structures, It gives the meteorological parameters like wind velocity and directions. In addition to this implementation of certain algorithms makes it possible to estimate mixing heights and depth of the Planetary Boundary Layer. These parameters can be input to the pollution dispersion models. You need three beam minimum to get total wind vector in terms of u, u, and w. Sodar intensity returns are plotted and called as echogram. The back scattered signal is gain ramped for range correction and plotted. The resolution is decided by pulse width ?. The minimum range also is decided by the pulse width and antenna aperture. The echogram gives information on various atmospheric processes which decides the dynamics of the atmosphere. (author)

  19. Power and color Doppler settings for inflammatory flow - impact on scoring of disease activity in patients with rheumatoid arthritis

    DEFF Research Database (Denmark)

    Torp-Pedersen, SØren Tobias; Christensen, Robin

    2014-01-01

    Objectives: To determine how settings for power and color Doppler sensitivity varies on different high and intermediate range ultrasound (US) machines and to evaluate the impact of these changes on Doppler scoring of inflammatory joints Methods: Six different types of ultrasound machine were used. On each machine, the factory setting (FS) for superficial musculoskeletal scanning was used unchanged for both color and power Doppler modalities. The settings were then adjusted for increased Doppler sensitivity - study settings (SS). Eleven RA patients 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 (CF) - higher CF indicated higher sensitivity. Results: Power Doppler was more sensitive on half of the machines whereas color Doppler was more sensitive on the other half with both FS and SS. There was an average increase in Doppler sensitivity despite modality of 78% when SS were applied. Over the 6 machines, 2 Doppler modalities, and 2 settings, 7 patients varied between grades 0 and 3 with the other 4 patients between grades 0 and 2. Conclusion: The effect of using different machines, Doppler modalities, and settings has a considerable influence on the quantification of inflammation in RA patients and this must be taken into account in multi-centre studies. © 2014 American College of Rheumatology.

  20. Relationships of Doppler venous gas embolism to decompression sickness

    Energy Technology Data Exchange (ETDEWEB)

    Lambertsen, C.J.; Nishi, R.Y.; Hopkin, E.J.

    1999-07-01

    This report summarizes the results of a study investigating the use of Doppler-detected Venous Gas Embolism (VGE) in predicting the risk of decompression sickness in offshore operations. The background to the study is traced, and the conceptual relations of VGE and decompression sickness (DCS), and relations of diving and decompression stress indices are examined. The development of databases, and the variability of VGE within the individual subject and within subject groups at common levels of dive are discussed. The relations of high and low VGE grade incidence to bubble dynamics stress index, ancillary factors in decompression stress and effect, and VGE and DCS relations in National Hyperbaric Centre Trials of IFEM 1993 Draft Air Sur DO{sub 2} Tables are considered. (UK)

  1. Velocity distribution in recoil-distance Doppler-shift experiments

    International Nuclear Information System (INIS)

    The Recoil-Distance Doppler-Shift (RDDS) technique is a well established method to measure lifetimes of excited nuclear states in the pico-second range. In standard RDDS experiments at non-relativistc beam-energies, the velocities of the emerging recoils are usually distributed narrowly around a mean velocity v = left angle v right angle v. Under these circumstances, the effect of the velocity distribution is neglectable and the assumption that all nuclei move with the average velocity is justified. In this poster we investigate the influence of broader velocity distributions on lifetimes determined using the standard lifetime analysis-method DDCM. This can be observed, e.g., in experiments with thick targets. In particular, it is shown that the effect of the velocity distribution on the deduced lifetime is minimised at the maximum amplitude of the derivative of the decay function.

  2. Accuracy limits and window corrections for photon Doppler velocimetry

    International Nuclear Information System (INIS)

    Symmetric, plate-impact experiments were performed to validate photon Doppler velocimetry (PDV) with established shock wave diagnostics. Impact velocity measurements using shorting pins demonstrated that the velocity accuracy of PDV can be 0.1% or better. Shock velocities and refractive indices were also measured with PDV (at 1550 nm) and velocity interferometer system for any reflector (VISAR) (at 532 nm) to obtain window corrections for single crystal LiF (100), c-cut sapphire, and z-cut quartz. Time-dependent, free-surface velocity histories for shocked LiF(100) provide a direct comparison between PDV and VISAR diagnostics and illustrate the benefits and shortcomings of the new diagnostic. Further implications of these results are presented

  3. Investigation of Measurement Errors in Doppler Global Velocimetry

    Science.gov (United States)

    Meyers, James F.; Lee, Joseph W.

    1999-01-01

    While the initial development phase of Doppler Global Velocimetry (DGV) has been successfully completed, there remains a critical next phase to be conducted, namely the determination of an error budget to provide quantitative bounds for measurements obtained by this technology. This paper describes a laboratory investigation that consisted of a detailed interrogation of potential error sources to determine their contribution to the overall DGV error budget. A few sources of error were obvious; e.g., iodine vapor adsorption lines, optical systems, and camera characteristics. However, additional non-obvious sources were also discovered; e.g., laser frequency and single-frequency stability, media scattering characteristics, and interference fringes. This paper describes each identified error source, its effect on the overall error budget, and where possible, corrective procedures to reduce or eliminate its effect.

  4. Observing Molecular Spinning via the Rotational Doppler Effect

    CERN Document Server

    Korech, Omer; Gordon, Robert J; Averbukh, Ilya Sh; Prior, Yehiam

    2013-01-01

    When circularly polarized light is scattered from a rotating target, a rotational Doppler shift (RDS) emerges from an exchange of angular momentum between the spinning object and the electromagnetic field. Here, we used coherently spinning molecules to generate a shift of the frequency of a circularly polarized probe propagating through a gaseous sample. We used a linearly polarized laser pulse to align the molecules, followed by a second delayed pulse polarized at 45{\\deg} to achieve unidirectional molecular rotation. The measured RDS is orders of magnitude greater than previously observed by other methods. This experiment provides explicit evidence of unidirectional molecular rotation and paves the way for a new class of measurements in which the rotational direction of molecular reagents may be monitored or actively controlled.

  5. A Doppler-like strong light-matter interaction

    CERN Document Server

    Moret-Bailly, J

    2001-01-01

    While complicated, unreliable alternatives to Doppler effect were proposed, an elementary optical light- matter interaction provides one which is commonly observed in the labs, but with a distortion due to the use of short, powerful laser pulses. It is generally assumed that Raman scattering in gases is incoherent. This assumption fails if the pressure is lowered enough to increase the relaxation times over the length of light pulses; the ''Impulsive Stimulated Raman Scattering'' (ISRS), generally used to study dense matter with ultrashort laser pulses, is adapted to the low energy pulses making the incoherent light beams; the usual light is redshifted by some very low pressure gases while it propagates. To produce this adapted ISRS called ''Incoherent Light Spatially Coherent Raman Scattering" (ILSCRS), a molecule must have an hyperfine structure: polyatomic molecules must be heavy or have odd numbers of electrons; light atoms and the other molecules must be perturbed by a Stark or Zeeman effect. ILSCRS reds...

  6. Magnetic Doppler Imaging of He-strong star HD 184927

    CERN Document Server

    Yakunin, I; Bohlender, D; Kochukhov, O; Tsymbal, V

    2013-01-01

    We have employed an extensive new timeseries of Stokes I and V spectra obtained with the ESPaDOnS spectropolarimeter at the 3.6-m Canada-France-Hawaii Telescope to investigate the physical parameters, chemical abundance distributions and magnetic field topology of the slowly-rotating He-strong star HD 184927. We infer a rotation period of 9.53071+-0.00120 from H-alpha, H-beta, LSD magnetic measurements and EWs of helium lines. We used an extensive NLTE TLUSTY grid along with the SYNSPEC code to model the observed spectra and find a new value of luminosity. In this poster we present the derived physical parameters of the star and the results of Magnetic Doppler Imaging analysis of the Stokes I and V profiles. Wide wings of helium lines can be described only under the assumption of the presence of a large, very helium-rich spot.

  7. Doppler frequency in interplanetary radar and general relativity

    Science.gov (United States)

    Mcvittie, G. C.

    1972-01-01

    The change of frequency of an interplanetary radar signal sent from the earth to another planet or to a space probe is worked out according to general relativity. The Schwarzschild spacetime is employed and its null geodesics control the motion of the signals. Exact Doppler frequency formulas are derived for one-way and two-way radar in terms of an arbitrary Schwarzschild radial coordinate. A reduction to the special relativity case is used to interpret the formulas in terms of the relative radial velocity of emitter and target. The general relativity corrections are worked out approximately for each of three possible Schwarzschild radial coordinates, and a numerical example is given. The amount of the correction is different according as one or the other of the Schwarzschild coordinates is identified with the radius vector deduced from classical celestial mechanics. The identification problem is discussed.

  8. Doppler weather Radar based Nowcasting of cyclone Ogni

    Indian Academy of Sciences (India)

    Soma Sen Roy; V Lakshmanan; S K Roy Bhowmik; S B Thampi

    2010-04-01

    In this paper, we describe offline analysis of Indian Doppler Weather Radar (DWR) data from cyclone Ogni using a suite of radar algorithms as implemented on NEXRAD and the advanced algorithms developed jointly by the National Severe Storms Laboratory (NSSL) and the University of Oklahoma. We demonstrate the applicability of the various algorithms to Indian radar data, the improvement in the quality control and evaluate the benefit of nowcasting capabilities in Indian conditions. New information about the tropical cyclone structure, as derived from application of the algorithms is also discussed in this study. Finally, we suggest improvements that could be made to the Indian data collection strategies, networking and real-time analysis. Since this is the first study of its kind to process and utilize DWR data in a tropical climate, the suggestions on real-time analysis and data collection strategies made in this paper, would in many cases, be beneficial to other countries embarking on DWR network modernization programs.

  9. Velocity bias in two component individual realization laser Doppler velocimetry

    International Nuclear Information System (INIS)

    In addition to the typical biasing problems associated with one component Laser Doppler Velocimetry (LDV), two component LDV measurements can suffer from other types of bias. In particular, coincidence bias is of interest. This type of velocity bias results from requiring simultaneous, or nearly simultaneous, measurements of the velocity components. In this study, two velocity bias correction schemes, based on the time between velocity samples, together with three different approaches for constant time-interval sampling of the velocity data have been evaluated. The effects of coincidence seeding rate and coincidence time window on velocity, normal, and Reynold's stress measurements are presented. Measurements with narrow coincidence window settings and/or low coincidence seeding rate resulted in velocity measurements which were larger than the true local average

  10. Positron annihilation Doppler broadening study of Xe-implanted aluminum

    Energy Technology Data Exchange (ETDEWEB)

    Yu, R.S., E-mail: yursh@ihep.ac.cn [Key Laboratory of Nuclear Analysis Techniques, Institute of High Energy Physics, Chinese Academy of Sciences, No. 19 Yuquan Lu, Beijing 100049 (China); Maekawa, M.; Kawasuso, A. [Japan Atomic Energy Agency, Advanced Science Research Center, Watanuki 1233, Takasaki, Gunma 370-1292 (Japan); Wang, B.Y.; Wei, L. [Key Laboratory of Nuclear Analysis Techniques, Institute of High Energy Physics, Chinese Academy of Sciences, No. 19 Yuquan Lu, Beijing 100049 (China)

    2013-10-01

    Positron annihilation Doppler broadening measurements were conducted to characterize information of defects in 380 keV Xe{sup +}-implanted aluminum upon thermal annealing at temperatures ranging from 100 to 600 °C. The results suggest a broad distribution in the depth of vacancy-type defects in all the as-implanted samples. Meanwhile, with an increase in implantation dose the defect-rich region shifts toward the sample surface. It was found that increasing the annealing temperature triggers surface-directed migration and coalescence of vacancy and Xe{sub n}V{sub m} clusters in samples with implantation doses of 1E15 and 1E16 Xe{sup +}cm{sup ?2}. In the sample implanted with a high dose of 1E17 Xe{sup +}cm{sup ?2}, positron annihilation revealed a decomposition and even elimination of such defects under post-implantation annealing treatment.

  11. Refinement of range-Doppler imagery by feedback control

    Science.gov (United States)

    Flores, Benjamin C.; Ugarte, Alberto

    1993-10-01

    This paper describes extended work on a comprehensive rotational-motion estimation and compensation technique to improve the quality of range-Doppler imagery. The approach assumes that the target signature is a collection of samples in the frequency space aperture plane. Motion compensation is performed via a polar reformatting scheme that requires knowledge of target kinematics, while motion estimation is accomplished by monitoring an entropy-like function in terms of kinematic parameter estimates. When properly selected, the entropy-like function becomes an accurate measure of image sharpness, and can thus be used to control a down-hill simplex search which yields an optimum set of rotational-motion parameter estimates. Ultimately, this set is needed to produce an optimally focused target image.

  12. Doppler-Based Flow Rate Sensing in Microfluidic Channels

    Directory of Open Access Journals (Sweden)

    Liron Stern

    2014-09-01

    Full Text Available We design, fabricate and experimentally demonstrate a novel generic method to detect flow rates and precise changes of flow velocity in microfluidic devices. Using our method we can measure flow rates of ~2 mm/s with a resolution of 0.08 mm/s. The operation principle is based on the Doppler shifting of light diffracted from a self-generated periodic array of bubbles within the channel and using self-heterodyne detection to analyze the diffracted light. As such, the device is appealing for variety of “lab on chip” bio-applications where a simple and accurate speed measurement is needed, e.g., for flow-cytometry and cell sorting.

  13. Sub-Doppler cooling of sodium atoms in gray molasses

    CERN Document Server

    Colzi, Giacomo; Fava, Eleonora; Serafini, Simone; Lamporesi, Giacomo; Ferrari, Gabriele

    2015-01-01

    We report on the realization of sub-Doppler laser cooling of sodium atoms in gray molasses using the D1 optical transition ($3s\\, ^2S_{1/2} \\rightarrow 3p\\, ^2P_{1/2}$) at 589.8 nm. The technique is applied to samples containing $3\\times10^9$ atoms, previously cooled to 350 $\\mu$K in a magneto-optical trap, and it leads to temperatures as low as 9 $\\mu$K and phase-space densities in the range of $10^{-4}$. The capture efficiency of the gray molasses is larger than 2/3, and we observe no density-dependent heating for densities up to $10^{11}$ cm$^{-3}$.

  14. Potential for coherent Doppler wind velocity lidar using neodymium lasers

    Science.gov (United States)

    Kane, T. J.; Byer, R. L.; Zhou, B.

    1984-01-01

    Existing techniques for the frequency stabilization of Nd:YAG lasers operating at 1.06 micron, and the high-gain amplification of radiation at that wavelength, make possible the construction of a coherent Doppler wind velocity lidar using Nd:YAG. Velocity accuracy and range resolution are better at 1.06 micron than at 10.6 microns at the same level of the SNR. Backscatter from the atmosphere at 1.06 micron is greater than that at 10.6 microns by about 2 orders of magnitude, but the quantum-limited noise is higher by 100 also. Near-field attenuation and turbulent effects are more severe at 1.06 micron. In some configurations and environments, the 1.06-micron wavelength may be the better choice, and there may be technological advantages favoring the use of solid-state lasers in satellite systems.

  15. Externally Dispersed Interferometry for Resolution Boosting and Doppler Velocimetry

    Energy Technology Data Exchange (ETDEWEB)

    Erskine, D J

    2003-12-01

    Externally dispersed interferometry (EDI) is a rapidly advancing technique for wide bandwidth spectroscopy and radial velocimetry. By placing a small angle-independent interferometer near the slit of an existing spectrograph system, periodic fiducials are embedded on the recorded spectrum. The multiplication of the stellar spectrum times the sinusoidal fiducial net creates a moire pattern, which manifests high detailed spectral information heterodyned down to low spatial frequencies. The latter can more accurately survive the blurring, distortions and CCD Nyquist limitations of the spectrograph. Hence lower resolution spectrographs can be used to perform high resolution spectroscopy and radial velocimetry (under a Doppler shift the entire moir{acute e} pattern shifts in phase). A demonstration of {approx}2x resolution boosting (100,000 from 50,000) on the Lick Obs. echelle spectrograph is shown. Preliminary data indicating {approx}8x resolution boost (170,000 from 20,000) using multiple delays has been taken on a linear grating spectrograph.

  16. Effects on doppler profiles in beam-heated plasmas

    International Nuclear Information System (INIS)

    We analyze various effects that can influence ion temperature measurements based on Doppler broadening of impurity lines. Macroscopic effects such as inhomogeneities, plasma rotation and temporal modulations are distinguished from microscopic ones leading to species-dependent temperatures and anisotropy in the impurity distribution functions. There are turbulent effects related to the latter that can also cause deviations from thermodynamic equilibrium among light and heavy impurities. It is found that under neutral-beam-heated JET conditions, all effects should be small and influence the measured ion temperature by less than ? 10%. Larger influences could be expected from strongly peaked rotation profiles - for which, however, no indications are found - and high-level turbulence, which appears rather unrealistic, too. (author)

  17. Neuroticism and vigilance revisited: A transcranial doppler investigation.

    Science.gov (United States)

    Mandell, Arielle R; Becker, Alexandra; VanAndel, Aaron; Nelson, Andrew; Shaw, Tyler H

    2015-11-01

    Selecting for vigilance assignments remains an important factor in human performance research. The current study revisits the potential relationship between vigilance performance and trait neuroticism, in light of two possible theories. The first theory suggests that neuroticism impairs vigilance performance by competing for available resources. The second theory, attentional control theory, posits that high neuroticism can result in similar or superior performance levels due to the allocation of compensatory effort. In the present study, Transcranial Doppler Sonography was used to investigate the neurophysiological underpinnings of neuroticism during a 12-min abbreviated vigilance task. Performance results were not modified by level of neuroticism, but high neuroticism was associated with higher initial CBFV levels and a greater CBFV decrement over time. These findings indicate that participants higher in neuroticism recruited additional cognitive resources in order to achieve similar performance, suggesting that there is more of an effect on processing efficiency than effectiveness. PMID:26057404

  18. Ovarian and uterine periovulatory Doppler ultrasonography in bitches

    Directory of Open Access Journals (Sweden)

    Claudia C. Barbosa

    2013-09-01

    Full Text Available 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<0.05. In results the ultrasonographic features of the uterus were the same on all of the cycles and evaluated days. The uterus had an average diameter of 0.85±0.02cm. An increase in the volume of the ovaries and the diameter of the ovarian follicles were measured. Ovaries had a volume of 0.64±0.06cm³, and the follicles cavities had a diameter of 0.46 ± 0.01 cm on the day of ovulation. After ovulation, it was observed that some follicles not collapse in some cycles. Two days prior to ovulation, the uterine blood perfusion decreased. This decrease remained unchanged until ovulation. Following ovulation, we measured a gradual increase in the uterine perfusion and in the ovarian artery. This artery directed blood flow to the ovaries and increased the intra-ovarian perfusion on the day after ovulation. In conclusion, specific features are observed in the uterus and ovarian ultrasound image and Doppler values of their arteries presented on the periovulatory days and when associated allow to estimate more accurately the date of ovulation.

  19. Doppler Broadening Thermometry Based on Cavity Ring-Down Spectroscopy

    Science.gov (United States)

    Hu, Shui-Ming; Cheng, Cunfeng; Wang, Jin; Tan, Yan; Sun, Yu Robert; Liu, An-Wen; Zhang, Jin-Tao

    2014-06-01

    A Doppler broadening thermometry is implemented using a laser-locked cavity ring-down spectrometer [1,2] combined with a temperature-stabilized sample cell. The temperature fluctuation of the gas sample cell is kept below 1 mK for hours. The probing laser is frequency locked at a longitudinal mode of a Fabry-Pérot interferometer made of ultra-low-expansion glass, and the spectral scan is implemented by scanning the sideband produced by an electro-optic modulator. As a result, a kHz precision has been maintained during the measurement of the spectrum of 10 GHz wide. A ro-vibrational line of C_2H_2 is measured at sample pressures of a few Pa. Using a pair of mirrors with a reflectivity of 0.99997 at 787 nm, we are able to detect absorption line profiles with a signal-to-noise ratio of 10^5. Fitting of the recorded spectra allows us to determine the Doppler width with a statistical uncertainty of 10 ppm. Further improvements on the experimental reproducibility and investigations on the collision effects will probably lead to an optical determination of the Boltzmann constant with an uncertainty of a few ppm. H. Pan, C.-F. Cheng, Y. R. Sun, B. Gao, A.-W. Liu, S.-M. Hu, ``Laser-locked, continuously tunable high resolution cavity ring-down spectrometer," Rev. Sci. Instrum. 82, 103110 (2011) Y. R. Sun, H. Pan, C.-F. Cheng, A.-W. Liu, J.-T. Zhang, S.-M. Hu, ``Application of cavity ring-down spectroscopy to the Boltzmann constant determination," Opt. Express, 19, 19993 (2011)

  20. Triplex Doppler evaluation of the testes in dogs of different sizes / Avaliação Triplex Doppler dos testículos de cães de tamanhos diferentes

    Scientific Electronic Library Online (English)

    Mírley B., Souza; Antônio C., Mota Filho; Carmen V.S., Sousa; Cynthia L.B., Monteiro; Gabriela G., Carvalho; José N., Pinto; Jussiara C.S., Linhares; Lúcia D.M., Silva.

    2014-11-01

    Full Text Available Este trabalho teve como objetivo verificar se existem diferenças nos parâmetros dopplervelocimétricos entre cães de diferentes portes. Para tanto, foram utilizados 20 cães, sendo 10 cães de pequeno porte e 10 cães de grande porte. Foram avaliados pelo Triplex Doppler para localização da artéria test [...] icular nos segmentos de cordão espermático, marginal ao testículo e intratesticular. Após isso, o Doppler espectral foi acionado para cálculo dos parâmetros de velocidade de pico sistólico (VPS), velocidade diastólica final (VDF) e índices de resistência (IR) e pulsatilidade (IP). O volume testicular médio do testículo esquerdo foi significativamente maior que o direito em ambos os grupos. Ao Doppler, foram observadas diferenças dos valores entre os portes, sendo as velocidades no cordão espermático superiores nos animais de grande porte (P Abstract in english This study aimed to assess whether there are differences in Doppler velocimetry parameters between different sizes. Twenty dogs were equally divided into small and large groups used in this study. The dogs were evaluated using Triplex ultrasound. Testicular artery was located by Colour Doppler in th [...] e spermatic cord, marginal to the testes and intratesticular segments and then, spectral Doppler were used to calculate: peak systolic velocity (PSV), end diastolic velocity (EDV), resistance index (RI) and pulsatility index (PI). The mean testicular volume in the left side was significantly higher than the right side, in both groups. Doppler examination showed higher velocities (EDV) at spermatic cord in large dogs; marginal to the testes was observed higher velocities in small dogs; intratesticular region no differences were observed (P

  1. Color Doppler flow mapping of stenotic and regurgitant natural heart valves

    International Nuclear Information System (INIS)

    Color Doppler echocardiography has found widest application in reliable detection and assessment of severity of both atrio-ventricular and semi-lunar valve incompetence. The authors believe both the sensitivity and specificity of color Doppler for the detection of mitral and aortic regurgitation is very high in patients with adequate acoustic windows. In 82 patients with proven mitral regurgitation studied, the best correlations with angiography were noted when the maximum or average regurgitant jet are obtained by color Doppler from three standard 2-D echo planes (parasternal long and short axis and apical four chamber view) and expressed as a percentage of the left atrial area were considered. The criteria the authors used for assessment of tricuspid and pulmonary valve incompetence are similar to those used for mitral and aortic valve incompetence, but the lack of a good ''gold'' standard has hampered validation. The color Doppler technique also supplements conventional Doppler in the assessment of severity of stenotic lesions by facilitating parallel alignment of the continuous wave Doppler cursor line with the stenotic jet for accurate recording of maximal velocities and pressure gradients. The authors have found this method especially useful in the assessment of aortic stenosis. In conclusion, color Doppler flow mapping combined with conventional echocardiography provides, for the first time, a comprehensive noninvasive assessement of the severity of regurgitant and stenotic lesions

  2. The role of colour Doppler sonography in the diagnosis of lower limb Klippel–Trénaunay syndrome

    International Nuclear Information System (INIS)

    Aim: To investigate the accuracy of colour Doppler sonography as compared to phlebography in patients with Klippel-Trénaunay syndrome (KTS). Materials and methods: From September 2004 to May 2012, 59 consecutive patients seen in Shandong medical imaging research institute with a clinical suggestion of KTS were included. Thirty-four were female and 25 were male, with a mean age of 28.4 years. Colour Doppler sonography was used to assess the lower limb veins. The main sonographic criteria for a positive diagnosis were visualization of the lateral vein or sciatic vein, capillary haemangioma, and abnormality of the deep veins. These data were compared with phlebography findings. The ? statistic was used to determine the level of agreement. The sensitivity, specificity, positive and negative predictive values, and accuracy of colour Doppler sonography as a diagnostic test were assessed. Results: Colour Doppler sonography findings were positive in 21 of 59 patients with a clinical suggestion of KTS. The diagnosis was confirmed using phlebography in 22 patients. There were two false-positive results and one false-negative result by colour Doppler sonography. The ?-value was 0.892. Sensitivity, specificity, positive and negative predictive values, and accuracy for colour Doppler sonography were 95.4, 94.6, 91.3, 97.2, and 94.9%, respectively. Conclusion: Colour Doppler sonography is an accurate, reliable, and non-invasive investigation in the assessment of patients with suspected KTS

  3. Comparing Color Doppler Ultrasonography and Angiography to Assess Traumatic Arterial Injuries of the Extremities

    International Nuclear Information System (INIS)

    Traumatic events are one of the major causes of arterial injuries. Physical examination is not a good predictor of the extent of injuries and arteriography is considered as the gold standard for this purpose. In the recent years, noninvasive modalities are increasingly replacing diagnostic arteriography. Color Doppler ultrasonography (USG) is an excellent method to investigate arterial diseases. The present study aimed to evaluate the diagnostic value of color Doppler USG compared to conventional angiography in traumatic arterial injuries of extremities. Seventy-five patients with extremity trauma suspicious for arterial injury were examined by color Doppler USG just before angiography. Doppler pattern and flow states were assessed, then angiography was performed. The results of duplex USG were compared with angiography. Color Doppler USG had a sensitivity of 95% and specificity of 98% in diagnosis of arterial injury. Positive and negative predictive values of Doppler USG were 92.5% and 94.2%, respectively. Color Doppler USG can be used as a reliable modality with acceptable sensitivity and specificity values to screen hemodynamically stable patients with limb trauma suspicious for arterial injury

  4. 3-D ultrafast Doppler imaging applied to the noninvasive mapping of blood vessels in vivo.

    Science.gov (United States)

    Provost, Jean; Papadacci, Clement; Demene, Charlie; Gennisson, Jean-Luc; Tanter, Mickael; Pernot, Mathieu

    2015-08-01

    Ultrafast Doppler imaging was introduced as a technique to quantify blood flow in an entire 2-D field of view, expanding the field of application of ultrasound imaging to the highly sensitive anatomical and functional mapping of blood vessels. We have recently developed 3-D ultrafast ultrasound imaging, a technique that can produce thousands of ultrasound volumes per second, based on a 3-D plane and diverging wave emissions, and demonstrated its clinical feasibility in human subjects in vivo. In this study, we show that noninvasive 3-D ultrafast power Doppler, pulsed Doppler, and color Doppler imaging can be used to perform imaging of blood vessels in humans when using coherent compounding of 3-D tilted plane waves. A customized, programmable, 1024-channel ultrasound system was designed to perform 3-D ultrafast imaging. Using a 32 × 32, 3-MHz matrix phased array (Vermon, Tours, France), volumes were beamformed by coherently compounding successive tilted plane wave emissions. Doppler processing was then applied in a voxel-wise fashion. The proof of principle of 3-D ultrafast power Doppler imaging was first performed by imaging Tygon tubes of various diameters, and in vivo feasibility was demonstrated by imaging small vessels in the human thyroid. Simultaneous 3-D color and pulsed Doppler imaging using compounded emissions were also applied in the carotid artery and the jugular vein in one healthy volunteer. PMID:26276956

  5. Use of High Sensitivity GNSS Receiver Doppler Measurements for Indoor Pedestrian Dead Reckoning

    Directory of Open Access Journals (Sweden)

    Gérard Lachapelle

    2013-03-01

    Full Text Available Dead-reckoning (DR algorithms, which use self-contained inertial sensors combined with gait analysis, have proven to be effective for pedestrian navigation purposes. In such DR systems, the primary error is often due to accumulated heading drifts. By tightly integrating global navigation satellite system (GNSS Doppler measurements with DR, such accumulated heading errors can usually be accurately compensated. Under weak signal conditions, high sensitivity GNSS (HSGNSS receivers with block processing techniques are often used, however, the Doppler quality of such receivers is relatively poor due to multipath, fading and signal attenuation. This often limits the benefits of integrating HSGNSS Doppler with DR. This paper investigates the benefits of using Doppler measurements from a novel direct vector HSGNSS receiver with pedestrian dead-reckoning (PDR for indoor navigation. An indoor signal and multipath model is introduced which explains how conventional HSGNSS Doppler measurements are affected by indoor multipath. Velocity and Doppler estimated by using direct vector receivers are introduced and discussed. Real experimental data is processed and analyzed to assess the veracity of proposed method. It is shown when integrating HSGNSS Doppler with PDR algorithm, the proposed direct vector method are more helpful than conventional block processing method for the indoor environments considered herein.

  6. Cramér–Rao lower bound of laser Doppler measurements at moving rough surfaces

    International Nuclear Information System (INIS)

    Laser Doppler techniques are widely used for measuring both fluid flows and moving solid surfaces. The measurement uncertainty of laser Doppler sensors is fundamentally limited by the uncertainty of the Doppler frequency estimation. Generally, the minimum achievable uncertainty of any unbiased estimator is given by the Cramér–Rao lower bound (CRLB). While the CRLB is well known for laser Doppler burst signals of single tracer particles used in flow research, no analytical expression for the CRLB has been known up to now for scattered light signals of rough solid surfaces where speckle effects occur. Therefore, the aim of this paper is to close this gap and to provide a simple analytical expression for the CRLB for the Doppler frequency estimation from scattered light signals of moving rough solid surfaces for the first time. A comparison with experimental data demonstrates the validity of the derived analytical CRLB formula, which is also proven to be consistent with previous works. The progress for science is that this analytical CRLB formula enables both an easy estimation of the minimum achievable uncertainty of laser Doppler measurements at moving rough surfaces and a direct analysis of the influences of certain system and signal parameters on the measurement uncertainty. This reveals specific measuring features and capabilities of different laser Doppler techniques. In addition, the CRLB is a valuable tool to evaluate the efficiency of applied signal processing techniques

  7. Color doppler ultrasound of hepatocellular carcinoma : evaluation of recurrence after transcatheter arterial chemoembolization

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong Min; Huh, Jin Do; Cho, Young Duk; Lee, Sang Uk [Kosin Univ. College of Medicine, Pusan(Korea, Republic of)

    1999-12-01

    To evaluate the efficacy of color and pulsed Doppler ultrasound (US) for the detection of arterial revascularization of hepatocellular carcinoma (HCC) after transcatheter arterial chemoembolization (TACE). One hundred and four histologically proven HCCs (0.7-12.5 cm, mean 4.14 cm) of 87 consecutive patients who had undergone TACE using a Lipiodol-chemoagent suspension were examined using color Doppler equipment. The criteria for diagnosing arterial revascularization of HCC were detection of inward blood vessels within HCC and demonstration by spectral Doppler US of pulsatile arterial flow within the vessel. Color Doppler US was prospectively performed using a multi-Hertz probe (2.5-5 Hz), and was followed by digital subtraction angiography (DSA). In 37 of 104 HCCs in 87 patients treated with TACE, color and spectral Doppler US demonstrated intratumoral arterial flows, with peak systolic velocity of 4.2-220 (mean, 59) cm/sec. DSA revealed neovascularity or tumor stains in 38 HCCs (3.4-12.5 cm, mean 5.9 cm in size) including 37 which on Doppler US showed arterial flow. The remaining 66 of 104 HCCs (0.7-6.3 cm, mean 3.2 cm) did not stain during DSA. Doppler US showed a false negative result in only one HCC (4.6 cm, located at segment VIII of the Couinaud classification), which stained faintly during DSA. The sensitivity, specificity, and accuracy of color and spectral Doppler US used for the detection of recurrent HCC were 97.4%, 100%, and 99%, respectively. Color and spectral Doppler US is an effective method for the evaluation of arterial revascularization of HCC after TACE.

  8. Color doppler ultrasound of hepatocellular carcinoma : evaluation of recurrence after transcatheter arterial chemoembolization

    International Nuclear Information System (INIS)

    To evaluate the efficacy of color and pulsed Doppler ultrasound (US) for the detection of arterial revascularization of hepatocellular carcinoma (HCC) after transcatheter arterial chemoembolization (TACE). One hundred and four histologically proven HCCs (0.7-12.5 cm, mean 4.14 cm) of 87 consecutive patients who had undergone TACE using a Lipiodol-chemoagent suspension were examined using color Doppler equipment. The criteria for diagnosing arterial revascularization of HCC were detection of inward blood vessels within HCC and demonstration by spectral Doppler US of pulsatile arterial flow within the vessel. Color Doppler US was prospectively performed using a multi-Hertz probe (2.5-5 Hz), and was followed by digital subtraction angiography (DSA). In 37 of 104 HCCs in 87 patients treated with TACE, color and spectral Doppler US demonstrated intratumoral arterial flows, with peak systolic velocity of 4.2-220 (mean, 59) cm/sec. DSA revealed neovascularity or tumor stains in 38 HCCs (3.4-12.5 cm, mean 5.9 cm in size) including 37 which on Doppler US showed arterial flow. The remaining 66 of 104 HCCs (0.7-6.3 cm, mean 3.2 cm) did not stain during DSA. Doppler US showed a false negative result in only one HCC (4.6 cm, located at segment VIII of the Couinaud classification), which stained faintly during DSA. The sensitivity, specificity, and accuracy of color and spectral Doppler US used for the detection of recurrent HCC were 97.4%, 100%, and 99%, respectively. Color and spectral Doppler US is an effective method for the evaluation of arterial revascularization of HCC after TACE

  9. Doppler ultrasound scoring to predict chemotherapeutic response in advanced breast cancer

    Directory of Open Access Journals (Sweden)

    Singh Tej B

    2007-08-01

    Full Text Available Abstract Background Doppler ultrasonography (US is increasingly being utilized as an imaging modality in breast cancer. It is used to study the vascular characteristics of the tumor. Neoadjuvant chemotherapy is the standard modality of treatment in locally advanced breast cancer. Histological examination remains the gold standard to assess the chemotherapy response. However, based on the color Doppler findings, a new scoring system that could predict histological response following chemotherapy is proposed. Methods Fifty cases of locally advanced infiltrating duct carcinoma of the breast were studied. The mean age of the patients was 44.5 years. All patients underwent clinical, Doppler and histopathological assessment followed by three cycles of CAF (Cyclophosphamide, Adriamycin and 5-Fluorouracil chemotherapy, repeat clinical and Doppler examination and surgery. The resected specimens were examined histopathologically and histological response was correlated with Doppler findings. The Doppler characteristics of the tumor were graded as 1–4 for 50% and complete disappearance of flow signals respectively. A cumulative score was calculated and compared with histopathological response. Results were analyzed using Chi square test, sensitivity, specificity, positive and negative predictive values. Results The maximum Doppler score according to the proposed scoring system was twelve and minimum three. Higher scores corresponded with a more favorable histopathological response. Twenty four patients had complete response to chemotherapy. Sixteen of these 24 patients (66.7% had a cumulative Doppler score more than nine. The sensitivity of cumulative score >5 was 91.7% and specificity was 38.5%. The area under the ROC curve of the cumulative score >9 was 0.72. Conclusion Doppler scoring can be accurately used to objectively predict the response to chemotherapy in patients with locally advanced breast cancer and it correlates well with histopathological response.

  10. Utilidad del Doppler transcraneal en la resucitación de la parada cardíaca / Transcranial Doppler ultrasonography usefulness in cardiac arrest resuscitation

    Scientific Electronic Library Online (English)

    J.A., Álvarez-Fernández; M.M., Martín-Velasco; J.C., Igeño-Cano; R., Pérez-Quintero.

    2010-11-01

    Full Text Available Durante la resucitación cardiopulmonar y tras la recuperación de la circulación espontánea, una perfusión tisular efectiva determina el pronóstico final. La ultranosografía Doppler transcraneal (DTC) registra la velocidad y la pulsatilidad del flujo sanguíneo cerebral y permite realizar análisis hem [...] odinámicos «latido a latido». Durante la resucitación cardiopulmonar la velocidad sistólica máxima alcanzada refleja la perfusión cerebral en cada compresión torácica. Tras la recuperación de la circulación espontánea, la persistencia después de 2h de un patrón arterial cerebral hipodinámico (baja velocidad media y alta pulsatilidad en la DTC) pronostica mala recuperación neurológica. La presencia, precoz o tardía, de un patrón de DTC hiperémico (alta velocidad media y baja pulsatilidad) se asocia a mal pronóstico por evolución a hipertensión intracraneal; su aparición durante la fase de recalentamiento debería llevar a reinstaurar la hipotermia terapéutica La coincidencia de arterias con patrones hipodinámicos con otras normales o hiperdinámicas indica focos de hipoperfusión que son predictores de ictus. Abstract in english An effective tissue perfusion has decisive influence on the final prognosis both during cardiopulmonary resuscitation (CPR) and after recovery of spontaneous circulation (ROSC). The transcranial Doppler ultranosography (TCD) examines the velocity and pulsatility of cerebral blood flow, making it pos [...] sible to perform "beat to beat" hemodynamic analysis. During CPR, TCD peak systolic velocity reflects cerebral perfusion of the chest compressions. Beyond 2 hours after ROSC, persistence in the cerebral arteries of a hemodynamic TCD pattern (low velocities with high pulsatilities) predicts poor neurological prognosis. Early or delayed presence of a hyperemic TCD pattern (high velocities with low pulsatilities) is associated conclusively with evolution to intracranial hypertension and its appearance during the rewarming process should lead to immediate return to therapeutic hypothermia. The coincidence of hypodynamic cerebral arteries and others with normal or hyperemic TCD patterns may indicate the presence of focal hypoperfusion that could predict stroke after ROSC.

  11. Variabilidad interobservador de las presiones sistólicas por el método Doppler / Interobserver variability of the systolic pressures by the Doppler method

    Scientific Electronic Library Online (English)

    Alfredo, Aldama; Seuc, Armando; Bárbara, Reyes; Alicia, Rodríguez.

    2004-09-01

    Full Text Available Se estudiaron independientemente y a ciegas por 2 técnicos, 30 pacientes, a los cuales se les midió la presión arterial sistólica humeral, poplítea, pedia y tibial posterior en el lado derecho; para cuantificar la variabilidad interobservador en la medición de las presiones sistólicas de las extremi [...] dades con un velocímetro Doppler. Se encontraron valores de presiones arteriales entre 46 y 250 mmHg. En la arteria poplítea, al igual que en la pedia y la tibial posterior, se observa una recta de regresión con pendiente ligeramente negativa, a diferencia del brazo, donde la pendiente fue ligeramente negativa, con una media y rangos de intervalos de confianza para las diferencias y las medias de las diferencias más elevados en las piernas, que los observados al nivel del brazo. La variabilidad de medición entre los 2 observadores fue pequeña, destacándose la arteria poplítea como la responsable de las mayores diferencias Abstract in english 30 patients were independently and blindly studied by 2 technicians. Their humeral systolic, popliteal, pedal and posterior tibial arterial pressures were measured on the right side to quantify the interobserver variability in the measurement of the systolic pressures of the limbs with a Doppler spe [...] edometer. Arterial pressure values between 46 mmHg and 250 mmHg were found. In the popliteal artery and in the pedal and the posterior tibial, it was observed a regression straight line with a mildly negative slope, differently from the arm, where the slope was slightly negative, with a mean and confidence interval ranges for the differences and the means of the differences more elevated than the observed at the arm level. The measurement variablity between the 2 observers was small. The popliteal artery was stressed as the responsible for the greatest differences

  12. Variabilidad interobservador de las presiones sistólicas por el método Doppler Interobserver variability of the systolic pressures by the Doppler method

    Directory of Open Access Journals (Sweden)

    Alfredo Aldama

    2004-09-01

    Full Text Available Se estudiaron independientemente y a ciegas por 2 técnicos, 30 pacientes, a los cuales se les midió la presión arterial sistólica humeral, poplítea, pedia y tibial posterior en el lado derecho; para cuantificar la variabilidad interobservador en la medición de las presiones sistólicas de las extremidades con un velocímetro Doppler. Se encontraron valores de presiones arteriales entre 46 y 250 mmHg. En la arteria poplítea, al igual que en la pedia y la tibial posterior, se observa una recta de regresión con pendiente ligeramente negativa, a diferencia del brazo, donde la pendiente fue ligeramente negativa, con una media y rangos de intervalos de confianza para las diferencias y las medias de las diferencias más elevados en las piernas, que los observados al nivel del brazo. La variabilidad de medición entre los 2 observadores fue pequeña, destacándose la arteria poplítea como la responsable de las mayores diferencias30 patients were independently and blindly studied by 2 technicians. Their humeral systolic, popliteal, pedal and posterior tibial arterial pressures were measured on the right side to quantify the interobserver variability in the measurement of the systolic pressures of the limbs with a Doppler speedometer. Arterial pressure values between 46 mmHg and 250 mmHg were found. In the popliteal artery and in the pedal and the posterior tibial, it was observed a regression straight line with a mildly negative slope, differently from the arm, where the slope was slightly negative, with a mean and confidence interval ranges for the differences and the means of the differences more elevated than the observed at the arm level. The measurement variablity between the 2 observers was small. The popliteal artery was stressed as the responsible for the greatest differences

  13. Laser Doppler holographic microscopy in transmission: application to fish embryo imaging

    CERN Document Server

    Verrier, Nicolas; Gross, Michel

    2014-01-01

    We have extended Laser Doppler holographic microscopy to transmission geometry. The technique is validated with living fish embryos imaged by a modified upright bio-microcope. By varying the frequency of the holographic reference beam, and the combination of frames used to calculate the hologram, multimodal imaging has been performed. Doppler images of the blood vessels for different Doppler shifts, images where the flow direction is coded in RGB colors or movies showing blood cells individual motion have been obtained as well. The ability to select the Fourier space zone that is used to calculate the signal, makes the method quantitative.

  14. Studies on delay-Doppler mapping of GNSS-R signals

    Science.gov (United States)

    Jing, Cheng; Yu, Yang; Yang, Xiaofeng; Ma, Wentao; Dong, Di; Li, Ziwei

    2015-08-01

    Global Navigation Satellite System can not only positioning but also emit microwaves of L band to the earth surface. With the reflection signals, we can obtain information about the sea surface. The Delay Doppler Map calculated from the received power recently play a key role in building relationships with the sea surface parameters. In this paper, the basics of Delay-Doppler Map are introduced and conducted by employing a set of new released TechDemoSat-1 GNSS-R data. In addition, sea surface parameters retrieved by using Delay-Doppler Maps are presented as a prospect.

  15. Uncertainty of Doppler reactivity worth due to uncertainties of JENDL-3.2 resonance parameters

    Energy Technology Data Exchange (ETDEWEB)

    Zukeran, Atsushi [Hitachi Ltd., Hitachi, Ibaraki (Japan). Power and Industrial System R and D Div.; Hanaki, Hiroshi; Nakagawa, Tuneo; Shibata, Keiichi; Ishikawa, Makoto

    1998-03-01

    Analytical formula of Resonance Self-shielding Factor (f-factor) is derived from the resonance integral (J-function) based on NR approximation and the analytical expression for Doppler reactivity worth ({rho}) is also obtained by using the result. Uncertainties of the f-factor and Doppler reactivity worth are evaluated on the basis of sensitivity coefficients to the resonance parameters. The uncertainty of the Doppler reactivity worth at 487{sup 0}K is about 4 % for the PNC Large Fast Breeder Reactor. (author)

  16. La ecografía Doppler en la detección de invasión vesical en la placenta percreta: nuestra experiencia

    Scientific Electronic Library Online (English)

    P., García Saraví; N.K., Patiño; M.L., Juana; J., Mariano; E., Reyna; R., Tizzano.

    2014-09-01

    Full Text Available Objetivo: Demostrar la utilidad de la ecografía Doppler en la detección de la invasión vesical en el percretismo placentario. Materiales y métodos: Se evaluó por ecografía, desde noviembre de 2011 hasta mayo de 2013, a 21 pacientes de entre 20 y 44 anos que tenían diagnóstico quirúrgico e histopatol [...] ógico de acretismo placentario (AP). Se consideró invasión vesical a la presencia de estructuras vasculares parietales en la evaluación Doppler color, mientras que se estableció como probable invasión a la presencia de otros hallazgos ecográficos sin senal Doppler. Resultados: De las 21 pacientes con acretismo placentario, 7 presentaron afectación vesical en el examen histopatológico: 5 tuvieron diagnóstico e informe ecográfico de invasión vesical (por la detección de estructuras vasculares en la evaluación Doppler color) y en las 2 restantes se planteó una probable afectación. De las 14 pacientes sin afectación vesical en el resultado histopatológico, hubo 7 con informes normales en la ecografía y 7 con resultados probables. Conclusión: La ecografía Doppler es un método muy útil para la detección de la invasión vesical en el percretismo placentario. Esta se observa con una vascularización parietal positiva en el Doppler color. Abstract in english Purpose: To demonstrate the usefulness of Doppler ultrasound in the detection of bladder invasion in cases of placenta percreta. Materials and methods: Twenty-one patients, aged 20-44 years old, with surgery and histopathological diagnosis of placenta accreta were tested with ultrasound between Nove [...] mber 2011 and May 2013. We considered bladder invasion the presence of hypervascularity detected with Doppler ultrasound, and probable invasion the presence of signs in gray-scale ultrasound, without Doppler color. Results: From the 21 patients included in the study with placenta accreta, 7 had bladder invasion in the histopathological study. Out of these seven, five had been reported to have bladder invasion because of the presence of hypervascularity detected with Doppler ultrasound, and the 2 remaining were reported as probably affected. Regarding the other 14, 7 were reported as normal in the ultrasound, and 7 as probable. Conclusion: Doppler ultrasound is a very reliable method to detect bladder invasion in placenta percreta, seen as hipervascularity of the uterine-bladder interface in the Doppler color exam.

  17. Assessment of hemodynamic disturbances in aphasic patients by transcranial Doppler ultrasonography.

    Science.gov (United States)

    Pendefunda, L

    1989-01-01

    The author presents a study of Doppler cerebrovascular ultrasonography carried out in 38 aphasie patients (forms ranging from transient speech disturbances to severe, persistent disturbances of motor, sensory or mixed aphasia) after ischemic or hemorrhagic stroke. In these cases, the clinical symptoms were dominated by speech impairment and neurological deficits (mainly pyramidal), of low intensity or transient. The angiographic study revealed stenotic or occlusive disturbances at various levels of the cerebral arterial trunks. The prevalence of some clinical aspects of aphasia correlated with Doppler velocimetric images is discussed and the use of transcranial Doppler method in idiopathic aphasia, possible consequence of a transient ischemic attack, is suggested. PMID:2479971

  18. Quasi-anomalous Doppler effect in a periodic-waveguide cyclotron maser

    Science.gov (United States)

    Korol, M.; Jerby, E.

    1996-02-01

    The quasi-anomalous Doppler effect is proposed in this paper as a new operating regime for cyclotron-resonance masers (CRMs). It combines features of the known normal and anomalous Doppler effects. A linear analysis of the CRM interaction shows that the quasi-anomalous Doppler effect may occur with fast em waves in inductive (low-impedance) periodic waveguides, and that it may produce gain without an initial rotation of the electron beam. A practical scheme of a slotted-waveguide CRM operating in the high frequency passband is proposed for a future experiment.

  19. Bilateral parvus-tardus Doppler waveform in renal arteries suggests aortic coarctation: case report

    International Nuclear Information System (INIS)

    Doppler ultrasonography (US) is an effective, inexpensive and widely used modality in renal vascular imaging. Demonstration of a parvus-tardus waveform pattern in renal arteries or intrarenal segmental arteries with Doppler US indicates a significant proximal stenosis. In the presence of a parvus-tardus pattern in both renal arteries, bilateral renal artery stenosis or a stenosis more proximal to the renal arteries should be considered.1 We present such a case and describe the Doppler ultrasonographic findings that suggested coarctation of the aorta. (author)

  20. Bilateral parvus-tardus Doppler waveform in renal arteries suggests aortic coarctation: case report

    Energy Technology Data Exchange (ETDEWEB)

    Conkbayir, I.; Yanik, B.; Keyik, B.; Edguer, T.; Hekimoglu, B. [Social Security Ankara Hospital, Dept. of Radiology, Diskapi, Ankara (Turkey)]. E-mail: iconkbayir@yahoo.com

    2004-02-01

    Doppler ultrasonography (US) is an effective, inexpensive and widely used modality in renal vascular imaging. Demonstration of a parvus-tardus waveform pattern in renal arteries or intrarenal segmental arteries with Doppler US indicates a significant proximal stenosis. In the presence of a parvus-tardus pattern in both renal arteries, bilateral renal artery stenosis or a stenosis more proximal to the renal arteries should be considered.{sup 1} We present such a case and describe the Doppler ultrasonographic findings that suggested coarctation of the aorta. (author)