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Sample records for tomografia axial computarizada

  1. Tomografía axial computarizada en pacientes con enfermedades cerebrovasculares hemorrágicas Computerized axial tomography in patients with hemorrhagic cerebrovascular diseases

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    Solángel Bolaños Vaillant

    2009-10-01

    Full Text Available Se efectuó un estudio descriptivo y transversal de 196 pacientes con enfermedad cerebrovascular hemorrágica, que abarcó desde enero del 2004 hasta igual mes del 2005 en el Hospital Provincial Docente “Saturnino Lora” de Santiago de Cuba, a los cuales se indicó una tomografía axial computarizada. Al relacionar las imágenes tomográficas con los síntomas y signos presentados por los enfermos, se halló lenguaje tropeloso en todos ellos; predominio de hematomas intraparenquimatosos, generalmente en ganglios basales y región temporal, así como primacía de la hipertensión arterial entre los antecedentes patológicos más importantes. Se concluyó que la tomografía axial computarizada es un medio para diagnóstico certero en las urgencias médicas por esa grave afección.A descriptive and cross sectional study of 196 patients with cerebrovascular hemorrhagic disease was carried out from January, 2004 to the same month of 2005 in "Saturnino Lora" Teaching Provincial Hospital from Santiago de Cuba, to whom a computerized axial tomography was indicated. When relating the tomographic images with the symptoms and signs which they presented, trouble speaking was detected in all of them; prevalence of intraparenchymatous hematomas, generally in basal ganglia and temporal region, as well as prevalence of hypertension among the most important pathological history. It was concluded that computarized axial tomography is a mean for precise diagnosis in medical emergencies due to that serious disorder.

  2. Analysis of the results of CAT of thorax with bronchiectasis protocol, period 2000-2001 Hospital Calderon Guardia; Analisis de los resultados de TAC de torax con protocolo de bonquiectasias, periodo 2000-2001 Hospital Calderon Guardia

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    Pacheco Segura, Maureen [Costa Rica

    2003-07-01

    This investigation analyses the computerized axial tomography (CAT) of thorax with protocol of bronchiectasis. It was carried out in the Servicio de Radiologia e Imagenes Medicas of the Hospital Calderon Guardia, Costa Rica. The bronchiectasis is the abnormal permanent expansion of the bronchial tuber and is important to diagnose it because the patient can suffer of pulmonary infections, these can be accompanied by bronchial blood flow and hemoptysis. When they are disseminated can be associated with significant obstruction of the aerial tract. When they are gotten into focus can be confused with neoplasia and other diseases. From the bronchiectasis diagnosis it is used methods of image such as x-ray of thorax, bronchography and computerized axial tomography (CAT) of thorax, usually the diagnosis is confirmed by means of a computerized axial tomography (CAT); which is the image of election to establish the presence and extension of the bronchiectasis. In addition, this study analyzes the radiological clinical relation in the patients which were performed the computerized axial tomography (CAT) of thorax with protocol of bronchiectasis and it identifies the most suitable radiological technique to obtain a satisfactory result in the computerized axial tomography with protocol of bronchiectasis. [Spanish] En esta investigacion se analiza la tomografia axial computarizada (TAC) de torax con protocolo de bronquiectasis realizada en el Servicio de Radiologia e Imagenes Medicas del Hospital Calderon Guardia, Costa Rica. Las bronquiectasias se definen como la dilatacion permanente anormal de los bronquios y es importante diagnosticarlas porque el paciente puede sufrir de infecciones pulmonares. Ademas, estas pueden acompanarse de flujo sanguineo bronquial y hemoptisis. Cuando estan diseminadas se pueden asociar con obstruccion significativa de la via aerea. Si estan focalizadas se pueden confundir con neoplasias u otras enfermedades. Para el diagnostico de bronquiectasias

  3. Application of the axial tomography computed for the detection of bags of dampness in dry wood of Gmelina arborea (Roxb.); Aplicacion de la tomografia axial computarizada para la deteccion de bolsas de humedad en madera seca de Gmelina arborea (Roxb.)

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    Moya R, Roger; Munoz A, Freddy [Inst. Tecnologico de Costa Rica, Escuela de Ingenieria Forestal, Apdo. 159-7050, Cartago 7050(Costa Rica); Escalante, Ivan [Clinica Santa Fe, San Jose (Costa Rica)

    2006-07-01

    detectar y establecer los limites de la presencia de humedad en la madera de Gmelina arborea al lado de la exploracion de tomografia computarizada (CT-escaner), una tecnica aplicada en el diagnostico medico. Junto con las bolsas humedas, en la CT-del escaner se presentan imagenes de color gris y con valores bajos de la Unidad Hounsfield (UH) o numero CT. Cuando estos valores fueron transformados a la densidad de la madera, se determino que las bolsas humedas estaban a una densidad de unos 190 kg/m{sup 3}, un valor superior al normal de la madera. Ademas, fue posible observar el crecimiento de anillos de arboles en la CT-del escaneo de imagenes, una caracteristica importante para la investigacion dendrocronologica. Los resultados obtenidos permitieron demostrar que es posible aplicar esta tecnica en el proceso de produccion de madera, para detectar las zonas con un alto MC en el secado de la madera de Gmelina arborea. (autor)

  4. Costo-efectividad de la tomografía computarizada y la ecografía en el diagnóstico de apendicitis

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    Álvaro Sanabria

    2008-03-01

    Conclusiones. Los métodos diagnósticos por imágenes en los casos de duda diagnóstica de apendicitis, son más costo-efectivos que el examen clínico para definir la conducta terapéutica. La tomografía axial computarizada ofrece una mejor relación costo-efectividad en el sistema de salud prepagada y es casi equiparable a la ecografía para el plan obligatorio de salud.

  5. Immediate adverse reactions to intravenous iodinated contrast media in computed tomography Reacciones adversas inmediatas al contraste yodado intravenoso en tomografía computarizada Reações adversas imediatas ao contraste iodado intravenoso em tomografia computadorizada

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    Beatriz Cavalcanti Juchem

    2007-02-01

    Full Text Available This exploratory-descriptive, non-experimental quantitative research aimed to learn about immediate adverse reactions to intravenous iodinated contrast media in hospitalized patients submitted to computed tomography at a teaching hospital in the South of Brazil. During the study period, all adverse reactions showed mild intensity, at a frequency of 12.5% with ionic iodinated contrast media, and 1% with non-ionic contrast agent. The extravasation of contrast occurred in 2.2% of the injections in a peripheral vein without complications in any of the cases. The results are within the limits cited in international literature and suggest that tomography service professionals should know their own rates of adverse reactions to iodinated contrast agent, as well as the conditions in which they occur, in order to obtain evidence to evaluate the respective care delivery processes.Investigación cuantitativa del tipo exploratorio-descriptivo, de carácter no experimental. El objetivo consistía en conocer las reacciones adversas inmediatas al contraste yodado intravenoso en pacientes internados, sometidos a tomografía computarizada en un hospital escuela del sur de Brasil. Durante el período del estudio, todas las reacciones adversas tuvieron intensidad leve y una frecuencia del 12,5% con la utilización del contraste yodado iónico, y 1% con contraste no iónico. La extravasación del contraste ocurrió en un 2,2% de las inyecciones en vena periférica, no ocasionando complicaciones en ninguno de los casos. Los índices evidenciados en el presente estudio se mantuvieron dentro de los límites que constan en la revisión de literatura y, entre las recomendaciones, se sugiere que los servicios de tomografía conozcan los propios índices de reacciones adversas al contraste yodado y las condiciones en que ocurren, con la finalidad de obtener evidencias para evaluación de los respectivos procesos asistenciales.Pesquisa quantitativa, explorat

  6. Primeros pasos en la posturografía dinámica computarizada

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    Cristina CORDERO-CIVANTOS

    2018-01-01

    Full Text Available Introducción y objetivo: La posturografía dinámica computarizada (CDP es una técnica que nos va a permitir cuantificar de forma objetiva, como las diferentes patologías afectan la estabilidad postural de los pacientes y su evolución. Metodología: revisión narrativa. Resultados: En este trabajo vamos a repasar como se realizan y analizan las diferentes pruebas de la CDP; y su utilidad diagnóstica y terapéutica en la práctica otorrinolaringológica. Discusión y conclusiones: La posturografía dinámica computarizada es una prueba diagnóstico-terapéutica que permite cuantificar de forma objetiva y reproducible la estabilidad del paciente. Y aporta información relevante para planificar el tratamiento rehabilitador, así como para monitorizar su evolución.

  7. Analysis of fetal dose in CT procedures; Analisis de dosis fetal en procedimientos de tomografia computarizada

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    Ortiz Torres, A.; Plazas, M. C.

    2006-07-01

    It is the miracle of the life, that sublime formation, the given more beautiful gift for heaven's sake to our to exist, and it is consequently our responsibility to look after their protection and care. Today in day the quantity of radiation absorbed by the fetus in the treatments for radiodiagnostic, mainly in the procedures of on-line axial tomography, the fetus absorbs a considerable dose of radiation and the questions generated regarding if these doses, bear to a risk of malformations or if it is necessary the interruption of the pregnancy is very frequent. In most of the cases, the treatment with ionizing radiations that it is beneficial for the mother, is only indirectly it for the fetus that is exposed to a risk. The possibility that a fetus or a small boy contract cancer caused by the radiation it can be three times superior to that of the population in general, of there the importance of analyzing the goods of the prenatal irradiation and the main agents to consider for the estimate of the magnitude of the risk of the exhibitions in uterus. In the different circumstances in that these can happen in treatments of on-line axial tomography computerized. (Author)

  8. Broncofibroscopia Flexível e Tomografia Helicoidal Computorizada no diagnóstico do Carcinoma Pulmonar Não de Peq uenas Células

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    Ram Cicero

    1998-11-01

    Full Text Available RESUMO: Actualmente a avaliação dos Tumores Pulmonares e as alterações intratorácicas provocadas pelos mesmos pode ser analisada por Tomografia Axial Computorizada e Tomografia Helicoidal Computorizada (THC.Parece haver uma correlação entre as imagens detectadas pela Tomografia Helicoidal Computorizada (THC e as alterações cndoscópicas encontradas por Broncofibroscopia Flexível (BFB.O objectivo deste trabalho foi demonstrar essa eventual correlação.Estudaram-se 18 doentes com Carcinoma do Pulmão Não de Pequenas Células (CPNPC. Houve uma boa correlação da Tomografia Helicoidal Computorizada (THC e dos aspectos encontrados por Broncofibroscopia Flexível (BFB, nas estenoses intrínsecas ou extrínsecas dos Brônquios Principais (BP e Brônquios Lobares (BL.A Tomografa Helicoidal Computorizada (THC pennite a localização espacial do tumor e visualizar as alterações estruturais circunvizinhas secundánas ao crescimento do tumor. A Tomografia Helicoidal Computorizada (THC pennitiu ainda a visualização da árvore brônquica para além da obstrução completa do lúmen brônquico, nos doentes em que não se conseguiu visualizar por broncofibroscopia.Nos tumores periféricos houve demonstração pela Tomografia Helicoidal Computorizada (THC de alterações estruturais da árvore brônquica que por Broncofibroscopia Flexível (BFB foram consideradas normais.Nesta série houve uma correlação directa entre a Tomografia Helicoidal Computorizada (THC e a Broncofibroscopia Flexível (BFB em quinze dos dezoito doentes estudados havendo uma sensibilidade de 83% no diagnóstico do tumor por broncofibroscopia. COMENTÁRIO: A Tomografia Helicoidal Computorizada (THC permite faze r o diagnóstico do cancro do pulmão em três dimensões visualizando as alterações estruturais circunvizinhas.As alterações endoscópicas visualizadas por Broncofibroscopia Flexível (BFB continuam a ser importantes, pela análise macroscópica das lesões e

  9. Seguimiento posterior a la cirugía curativa para el cáncer colorrectal: impacto de la tomografía por emisión de positrones - tomografía computarizada (PET/TC)

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    Kishimoto, Gustavo; Murakami, Koji; Con, Sergio A.; Yamasaki, Erena; Domeki, Yasushi; Tsubaki, Masahiro; Sakamoto, Setsu

    2010-01-01

    El seguimiento postoperatorio tiene un rol importante para la sobrevida del paciente después de la resección curativa del cáncer colorrectal. OBJETIVOS: Describir las características del seguimiento con tomografía por emisión de positrones (PET) integrado a tomografía axial computarizada (CT) (PET/CT) y su impacto en los sobrevivientes de cáncer colorrectal (CCR) posterior a la resección con intención curativa en un hospital universitario en la prefectura de Tochigi, Japón. MATERIAL Y MÉTODOS...

  10. Criptococose pulmonar: aspectos na tomografia computadorizada

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    Silva Ana Carina Gamboa da

    2003-01-01

    Full Text Available A criptococose pulmonar é uma doença causada pelo Criptococcus neoformans, um fungo unimórfico que possui distribuição mundial, existindo na mesma forma tanto no seu habitat natural quanto em animais e humanos. A doença possui apresentações clínica e patológica variáveis e pode manifestar-se tanto em pacientes com a imunidade normal como em imunocomprometidos, que representam a maioria dos casos. Neste trabalho são analisados os aspectos encontrados nas tomografias computadorizadas do tórax de 14 pacientes com criptococose pulmonar confirmada. Os achados mais freqüentes na tomografia do tórax foram as massas e os nódulos pulmonares. Outros aspectos observados foram as áreas de escavação, as consolidações, o espessamento do interstício peribroncovascular e o reticulado difuso. Massa pulmonar foi o achado isolado mais comum (64,2%, seguido dos nódulos isolados ou múltiplos (35,7%. Doença pulmonar difusa foi vista em apenas 14,2% dos casos. Os lobos superiores foram os mais comprometidos, sendo a doença mais comum nas regiões anteriores. A tomografia do tórax permitiu avaliar com precisão o grau de comprometimento do parênquima pulmonar.

  11. Diseño y validación de una tarea computarizada tipo Stroop para evaluar sesgos de la atención en bulimia nerviosa

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    Camacho-Ruíz, Esteban Jaime; Mancilla-Díaz, Juan Manuel; Escoto-Ponce De León, María Del Consuelo; Yáñez-Tellez, María Guillermina

    2009-01-01

    Objetivo: Desarrollar una tarea computarizada tipo Stroop para evaluar sesgos en la atención hacia palabras relacionadas con la comida y la figura, en pacientes con bulimia nerviosa. Se desarrollaron cuatro listas de palabras con valencia positiva y negativa, relacionadas con la comida y la figura corporal. Método: treinta y dos mujeres con bulimia nerviosa emparejadas con 32 mujeres sin trastorno, respondieron la versión original y una modificada de la Prueba de Stroop computarizada. Resulta...

  12. Diseño y Validación de una Tarea Computarizada Tipo Stroop para Evaluar Sesgos de la Atención en Bulimia Nerviosa

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    Esteban Jaime Camacho-Ruíz

    2009-01-01

    Objetivo: Desarrollar una tarea computarizada tipo Stroop para evaluar sesgos en la atención hacia palabras relacionadas con la comida y la figura, en pacientes con bulimia nerviosa. Se desarrollaron cuatro listas de palabras con valencia positiva y negativa, relacionadas con la comida y la figura corporal. Método: treinta y dos mujeres con bulimia nerviosa emparejadas con 32 mujeres sin trastorno, respondieron la versión original y una modificada de la Prueba de Stroop computarizada. Resulta...

  13. Solitary pulmonary nodule: radiologic features and diagnostic approach; Nodulo pulmonar solitario: caracteristicas radiologicas y abordaje diagnostico

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    Rodriguez Cambronero, Luis Enrique

    2012-07-01

    A literature review is conducted on the solitary pulmonary nodule, to determine the diagnostic methods and specific characteristics. The diagnostic methods used have been: chest radiography, computed tomography, positron emission tomography and magnetic resonance imaging. The radiological features are defined: location, size, definition of contours or edges (margins), densitometric and attenuation characteristics, cavitation, air bronchogram, growth, doubling time, satellite nodules, nutrient vessels [Spanish] Una revision bibliografica es realizada sobre el nodulo pulmonar solitario, para determinar los metodos de diagnostico y caracteristicas especificas. Los metodos de diagnostico utilizados han sido: la radiografia de torax, tomografia computarizada, tomografia por emision de positrones y resonancia magnetica. Las caracteristicas radiologicas son definidas: localizacion, tamano, definicion de los bordes o contornos (margenes), caracteristicas densitometricas y de atenuacion, cavitacion, broncograma aereo, crecimiento, tiempo de duplicacion, nodulos satelite, vasos nutrientes.

  14. Alteraciones neuropsicológicas en el alcoholismo crónico

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    Junqué i Plaja, Carme, 1955-; Jurado, Ma. Ángeles (María Ángeles)

    1991-01-01

    El déficit neuropsicológico asociado al alcholismo abarca diversas funciones: memoria, razonamiento abstracto, solución de problemas y ha- bilidades perceptivo-motoras. Estructuralmente, los cambios cerebrales ob- servados con m i s frecuencia en la Tomografia Computarizada (TC) son la atrofia cerebral difusa y la dilatación ventricular. La dilatación ventri- cular es la medida de atrofia cerebral que m i s correlaciona con el déficit neuropsicológico. Desde ei punto de vista funcional, el fl...

  15. Auxílio da tomografia computadorizada no planejamento pré-operatório de pacientes portadores de escoliose idiopática do adolescente Auxilio de la tomografía computarizada en el plan preoperatorio de pacientes portadores de escoliosis idiopática del adolescente Computed tomography aid in preoperative planning of patients with adolescent idiopathic scoliosis

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    Rodrigo Rezende

    2010-03-01

    Full Text Available A escoliose idiopática do adolescente (EIA é uma doença diagnosticada no início da puberdade. Ela apresenta etiologia indefinida e caracteriza-se pelo desvio lateral da coluna vertebral maior que 10°, associado à rotação do corpo vertebral. O uso de instrumentação de terceira geração produziu um melhor resultado na correção da curva do que as técnicas anteriores. Porém, ainda existem dificuldades técnicas no momento da passagem e da escolha dos parafusos pediculares, devido à angulação e ao diâmetro dos pedículos vertebrais. Apesar de apresentar vantagens, essa técnica não é isenta de riscos e complicações, necessitando de uma maior curva de aprendizado pelo médico-cirurgião, bem como de um adequado planejamento pré-operatório. Até o momento, não há na literatura relato sobre a utilização da tomografia computadorizada no auxílio do planejamento cirúrgico de pacientes com escoliose. Diante do exposto, objetivamos, no presente estudo, descrever uma técnica de planejamento pré-operatório, com o auxílio da tomografia computadorizada para a fixação da coluna em pacientes com escoliose idiopática do adolescente, especificando a angulação e o diâmetro dos pedículos vertebrais, o que poderá auxiliar o médico-cirurgião no momento da fixação.La escoliosis idiopática en el adolescente (EIA es una enfermedad diagnosticada en el inicio de la pubertad. Esta presenta una etiología indefinida y es caracterizada por el desvío lateral de la columna vertebral por encima de los diez grados asociados a la rotación del cuerpo vertebral. El uso de instrumentación de tercera generación produjo un mejor resultado en la corrección de la curva comparado con las técnicas anteriores. Sin embargo, existen dificultades técnicas en el momento del paso y de escoger los tornillos pediculares debido a la angulación y al diámetro de los pedículos vertebrales. A pesar de presentar ventajas, esta técnica no est

  16. Tomografia computadorizada no seguimento de pacientes com tumores intracranianos

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    Gilberto Machado de Almeida

    1981-03-01

    Full Text Available A tomografia computadorizada tem grande valor no controle dos pacientes com tumores cerebrais. Imediatamente após o ato cirúrgico pode ser útil para avaliar a retirada do processo expansivo ou para comprovar a área atingida. Nos primeiros dias após a intervenção tem sido indicada principalmente quando há piora do quadro neurológico. Nestas condições, o exame permite verificar a existência de ar, edema, hematoma, desvios ventriculares e hidrocéfalo. Os dados fornecidos são mais precisos que os obtidos com outros exames neuror-radiológicos ou com a medida contínua da pressão intracraniana, métodos menos inócuos. A longo prazo a tomografia permite o diagnóstico precoce de recidivas, a avaliação da eficácia de tratamentos radio ou quimioterápicos e o controle do hidrocéfalo. Ainda não é possível fazer o diagnóstico diferencial entre radio-necrose e recidiva tumoral.

  17. Correlação entre hipótese diagnóstica e laudo de tomografia axial computadorizada craniana Correlation between diagnostic hypothesis and result of cranial computed axial tomography

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    Edison Matos Nóvak

    2001-09-01

    Full Text Available Para avaliar a utilização da tomografia axial computadorizada craniana (TC em nosso meio, analisamos as solicitações de 367 exames consecutivos no período compreendido entre 07/1995 e 07/1996. Houve ampla variação da faixa etária, com média de 31,7 ± 22,9 anos. As especialidades que mais solicitaram o exame foram: Neurologia (36,2%, Pronto Atendimento (17,4%, Neuropediatria (16,9% e Clínica Médica (5,9%. As indicações mais frequentes para o exame foram: convulsão (30%, cefaléia (26,2%, déficit motor (20,2% e redução do nível de consciência (16,9%. As "hipóteses" aventadas com maior frequência foram: afastar lesão estrutural (9,0%, acidente vascular não discriminado (8,2% e neurocisticercose (8,2%. O laudo da TC foi normal em 50,4% dos exames. Os laudos anormais mais frequentes foram: hidrocefalia (5,4%, acidente vascular isquêmico (5,4% e neoplasia (3,5%. As maiores taxas de achados normais foram encontradas nas "hipóteses" de cefaléia (94,4%, convulsão (71,4% e afastar lesão estrutural (66,7%. Os maiores índices de acerto entre hipótese e laudo foram encontrados nas situações de "afastar lesões estruturais" (66,7%, hidrocefalia (50%, acidente vascular cerebral isquêmico (50% e hematoma (50%. Concluimos que a utilização de um recurso auxiliar de diagnóstico como a TC cumpre melhor ainda a sua função se o requisitante do exame preencher com clareza e detalhamento o pedido do exame.The use of computed axial tomography (CT in the investigation of neurologic disorders is attractive for his disponibility in the health services. However, the indications of the exam and the correlation with the clinical features has not been frequently studied. We study correlation between the requests of CT and the findings reported by the radiologist, in 367 exams performed from 07/1995 to 07/ 1996. The mean age was 31.7 ± 22.9 years. The CT were requested in decrescent order of frequency by the Services of Neurology (36

  18. Determinación del color en epicarpios de mango (Mangifera sp. y plátano (Musa AAB en maduración mediante sistema de visión computarizada

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    Carlos Alberto Padrón Pereira

    2012-01-01

    Full Text Available En investigación agraria y alimentaria, el procesamiento y análisis de imágenes en color se ha convertido en un área importante de estudio. En este contexto, el sistema de visión computarizada ha demostrado ser un procedimiento útil. Los propósitos de este trabajo fueron determinar el color en epicarpios de frutos de mango y plátano durante la maduración con sistema de visión computarizada. El sistema lo constituyó un escenario iluminado, una cámara digital CCD y un computador (desktop, ambos calibrados. El procesamiento digital de las imágenes se llevó a cabo con el software Adobe® Photoshop®, con el cual se generaron imágenes promediadas en coordenadas rectangulares L*, a*, b*. Las coordenadas polares (C*, hº fueron calculadas, y para todos los casos, los resultados fueron descritos. Los resultados permitieron describir adecuadamente las variaciones de color en epicarpios de ambos frutos durante la maduración, mediante coordenadas colorimétricas de los espacios de color CIE-L*a*b* y CIE-L*C*hº, a través de imágenes digitales obtenidas con sistema de visión computarizada.

  19. Determinación del color en epicarpios de mango (Mangifera sp. y plátano (Musa AAB en maduración mediante sistema de visión computarizada

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Padrón Pereira

    2012-12-01

    Full Text Available En investigación agraria y alimentaria, el procesamiento y análisis de imágenes en color se ha convertido en un área importante de estudio. En este contexto, el sistema de visión computarizada ha demostrado ser un procedimiento útil. Los propósitos de este trabajo fueron determinar el color en epicarpios de frutos de mango y plátano durante la maduración con sistema de visión computarizada. El sistema lo constituyó un escenario iluminado, una cámara digital CCD y un computador (desktop, ambos calibrados. El procesamiento digital de las imágenes se llevó a cabo con el software Adobe® Photoshop®, con el cual se generaron imágenes promediadas en coordenadas rectangulares L*, a*, b*. Las coordenadas polares (C*, hº fueron calculadas, y para todos los casos, los resultados fueron descritos. Los resultados permitieron describir adecuadamente las variaciones de color en epicarpios de ambos frutos durante la maduración, mediante coordenadas colorimétricas de los espacios de color CIE-L*a*b* y CIE-L*C*hº, a través de imágenes digitales obtenidas con sistema de visión computarizada.

  20. Reinforced concrete tomography; Tomografia de hormigon armado

    Energy Technology Data Exchange (ETDEWEB)

    Mariscotti, M A.J.; Morixe, M; Tarela, P A; Thieberger, P [Tomografia de Hormigon Armado S.A., Boulogne (Argentina)

    1998-12-31

    In this paper we describe the technique of reinforced concrete tomography, its historical background, recent technological developments and main applications. Gamma radiation sensitive plates are imprinted with radiation going through the concrete sample under study, and then processed to reveal the presence of reinforcement and defects in the material density. The three dimensional reconstruction, or tomography, of the reinforcement out of a single gammagraphy is an original development alternative to conventional methods. Re-bar diameters and positions may be determined with an accuracy of {+-} 1 mm 0.5-1 cm, respectively. The non-destructive character of this technique makes it particularly attractive in cases of inhabited buildings and diagnoses of balconies. (author) 8 refs., 12 figs. [Espanol] En este trabajo se describe la tecnica de tomografia de hormigon armado, sus antededentes, recientes desarrollos y aplicaciones mas importantes. Esta tecnica se basa en el uso de radiacion gamma para penetrar piezas de hormigon. Placas gammagraficas son sensibilizadas con la radiacion que atraviesa la pieza bajo estudio y luego procesadas para revelar la presencia de armadura e inhomogeneidades en la densidad del concreto. La reconstruccion tridimensional o tomografia, de la armadura a partir de una sola gammagrafia es un desarrollo original alternativo a los metodos convencionales. Diametros y posiciones de los hierros existentes en el interior de columnas, vigas y losas pueden ser determinados con precisiones de {+-} 1 mm y 0.5-1 cm, respectivamente. La condicion de no destructiva hace que esta tecnica sea particularmente apreciada en los casos de edificios habitados y sea insustituible para el diagnostico de balcones. (autor)

  1. Tomografia computadorizada no diagnóstico da otosclerose fenestral

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    Vicente Andy de Oliveira

    2004-01-01

    Full Text Available OBJETIVO: Identificar os principais achados tomográficos da otosclerose fenestral e avaliar a utilidade da tomografia computadorizada de alta resolução (TCAR, como método diagnóstico dessa osteodistrofia. FORMA DE ESTUDO: Estudo prospectivo multicêntrico com tomografia computadorizada (TC de ossos temporais. MATERIAL E MÉTODO: 54 pacientes com diagnóstico clínico e cirúrgico de otosclerose. Foi realizada uma análise tomográfica, em que foi avaliada a sensibilidade da TC no diagnóstico radiológico da otosclerose fenestral, sendo verificados os principais sítios de lesões dessa doença, como também a sua bilateralidade e simetria. Foram incluídos neste estudo 22 pacientes submetidos à TC de ossos temporais para investigação de outras afecções otológicas, que constituíram o grupo controle. RESULTADOS: A TC foi positiva em 87% dos pacientes (77% das orelhas. Os achados tomográficos foram bilaterais na maioria dos casos (78,7%, e o foco fenestral mais prevalente foi o foco anterior à janela oval (FAJO. CONCLUSÕES: A TC apresentou um alto índice de positividade e o FAJO foi o foco mais prevalente nessa população, podendo ser considerado um achado tomográfico altamente sugestivo de otosclerose.

  2. Avaliação da reprodutibilidade da tomografia computadorizada no estadiamento da pancreatite aguda Reproducibility in the assessment of acute pancreatitis with computed tomography

    Directory of Open Access Journals (Sweden)

    Edison de Oliveira Freire Filho

    2007-12-01

    Full Text Available OBJETIVO: Medir a reprodutibilidade da tomografia computadorizada sem e com contraste na avaliação da gravidade da pancreatite aguda. MATERIAIS E MÉTODOS: Cinqüenta e um exames de tomografia computadorizada abdominal sem e com contraste de pacientes com pancreatite aguda foram analisados por dois radiologistas (observadores 1 e 2. Calculamos o índice morfológico pela tomografia computadorizada sem e com contraste, separadamente, e o índice de gravidade da tomografia computadorizada para pancreatite aguda. Medimos a reprodutibilidade intra- e interobservador da tomografia computadorizada através do índice kappa (kapa. RESULTADOS: Para a concordância interobservador obtivemos kapa de 0,666, 0,705, 0,648, 0,547 e 0,631 para índice morfológico sem e com contraste, presença de necrose pancreática, extensão da necrose pancreática e índice de gravidade da tomografia computadorizada, respectivamente. Para a concordância intra-observador dos observadores 1 e 2 obtivemos, respectivamente, kapa de 0,796 e 0,732 para o índice morfológico sem contraste; 0,725 e 0,802 para o índice morfológico com contraste; 0,674 e 0,849 para a presença de necrose pancreática; 0,606 e 0,770 para a extensão da necrose pancreática; e 0,801 e 0,687 para o índice de gravidade da tomografia computadorizada. CONCLUSÃO: O estadiamento da pancreatite aguda pela tomografia computadorizada por meio do índice morfológico e do índice de gravidade da tomografia computadorizada é um método bastante reprodutível. O não-uso do contraste não afeta a reprodutibilidade da tomografia computadorizada para o cálculo do índice morfológico.OBJECTIVE: To evaluate the reproducibility of unenhanced and contrast-enhanced computed tomography in the assessment of patients with acute pancreatitis. MATERIALS AND METHODS: Fifty-one unenhanced and contrast-enhanced abdominal computed tomography studies of patients with acute pancreatitis were blindly reviewed by two

  3. Distorsión en imágenes obtenidas mediante tomografía computarizada de cono Distortion in cone-beam computed tomography images

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    Gloria Baena

    2013-06-01

    Full Text Available Objetivo: Cuantificar la distorsión presente en imágenes de diferentes regiones del cráneo y la mandíbula humanos obtenidas mediante tomografía computarizada de cono. Metodología: Mediante el trazo de 3 planos horizontales y 4 verticales se delimitaron 15 cuadrantes en 30 cráneos secos humanos con las mandíbulas articuladas y se colocaron en cada cuadrante alambres de acero inoxidable en los planos sagital, coronal y axial (transversal. A cada espécimen debidamente posicionado se le tomó una tomografía computarizada de cono (CBCT. Se midió la longitud de los alambres, tanto en los especímenes óseos (medida real, como en las imágenes (medida tomográfica, para compararlas entre sí. Como pruebas estadísticas se utilizaron el Coeficiente de Correlación de Concordancia (CCC y la Media de las Diferencias. Resultados: Dado que el CCC encontrado en todos los cuadrantes fue siempre mayor de 0,80, las medidas tomográficas que se hagan en estos cuadrantes pueden ser consideradas estadísticamente confiables. Sin embargo, los valores obtenidos en todas las medidas espaciales revelan que en todos los cuadrantes se presenta algún porcentaje de distorsión, siendo este de magnificación para algunos o de minimización para otros. La mayor distorsión se presentó en las medidas verticales de los cuadrantes situados en la línea mediana o próximos a ella, y el menor porcentaje en las medidas horizontales. Conclusión: La distorsión presente en las diferentes regiones del cráneo y la mandíbula no es estadísticamente significativa, pero es aconsejable tenerla en cuenta para minimizar los errores que puedan presentarse en la práctica clínica.Objective: To quantify the distortion in Cone-Beam Computed Tomography images of different regions of the human skull and mandible. Methods: With the tracing of three horizontal and four vertical planes, fifteen quadrants were delimited in thirty dry human skulls with their articulated jaws

  4. Análisis de la cuantifiación tridimensional de las vías lagrimales en tomografía computarizada

    OpenAIRE

    Jáñez García, Lucía

    2016-01-01

    La descripción de la anatomía del sistema de drenaje lagrimal en la literatura es poco precisa. Se han realizado mediciones del canal nasolagrimal óseo (CNLO) en cadáver, radiografía y tomografía computarizada (TC). JUSTIFICACIÓN, HIPÓTESIS DE TRABAJO Y OBJETIVOS Hasta ahora, todas las mediciones realizadas sobre imágenes tienen al menos un paso manual, lo que inevitablemente degrada la fiabilidad de los datos obtenidos. La mayoría de las mediciones realizadas en TC son bidimensionales y únic...

  5. Fabricación de biomodelos tridimensionales odontológicos a partir de tomografías computarizadas

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    Fabián Villena

    2017-10-01

    Full Text Available Este manuscrito tiene por objetivo establecer un flujo de trabajo para la construcción de biomodelos tridimensionales mediante la técnica de fabricación con filamento fundido. Se describen las características de tomografías computarizadas en formato DICOM, la generación de un modelo tridimensional desde los archivos DICOM y finalmente la manufactura (impresión, por medio de la tecnología de fabricación con filamento fundido. A través de este protocolo de trabajo es posible generar biomodelos tridimensionales paciente-específicos a bajo costo, donde la precisión de la tecnología con filamento fundido es confrontable con otros sistemas más costosos.

  6. Stratus optical coherence tomography findings in patients with retinopathy of prematurity Tomografia de coerência óptica em pacientes com retinopatia da prematuridade

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    Aline do Lago

    2007-02-01

    Full Text Available PURPOSE: To describe morphological features of the macula in patients with retinopathy of prematurity. METHODS: Twelve premature babies with retinopathy of prematurity grades I, II and III underwent dilated fundus examination and optical coherence tomography evaluation. RESULTS: In all thirteen eyes of the twelve premature patients optical coherence tomography revealed a condensed retinal pigmented epithelial layer in the macular-foveal area shown by increased reflectivity. In these eyes the retinal layers were not well differentiated. Foveal depression was clearly evident in 23%. CONCLUSIONS: In premature patients with retinopathy of prematurity, optical coherence tomography revealed poorly differentiated layers in the macular region with increased reflectivity in retinal pigmented epithelial-choriocapillaris zone.OBJETIVO: Descrever os aspectos morfológicos da mácula em pacientes com retinopatia da prematuridade (ROP. MÉTODOS: Doze pacientes com retinopatia da prematuridade graus I, II and III foram submetidos a mapeamento de retina e avaliação por tomografia de coerência óptica. RESULTADOS: Em todos os treze olhos de 12 pacientes a tomografia de coerência óptica mostrou a camada do epitélio pigmentar hiperrefletiva, sendo a área macular com maior intensidade. Nesses olhos as camadas da retina não estavam totalmente diferenciadas. A depressão foveal ficou claramente evidente pela tomografia de coerência óptica em 23%. CONCLUSÃO: Nos pacientes prematuros com retinopatia da prematuridade, a tomografia de coerência óptica mostrou as camadas da retina pouco diferenciadas com aumento da refletividade na área macular do complexo epitélio retiniano pigmentar-coriocapilar.

  7. A tomografia de córnea e segmento anterior na propedêutica do exame complementar na avaliação de ectasia

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    Bruno de Freitas Valbon

    2013-02-01

    Full Text Available Descrevemos a importância da tomografia de córnea e segmento anterior na propedêutica do exame complementar na avaliação de ectasia. Esta descrição da interpretação clínica dos índices da tomografia de córnea e segmento anterior (Pentacam - Oculus, Wetzlar, Germany neste relato de caso, demonstra a relevância de uma nova tecnologia na avaliação da córnea e segmento anterior na suspeita de ceratocone. O diagnóstico de ceratocone foi excluído pela análise dos índices tomográficos de ectasia. Detectou-se assimetria entre os lados nasal e temporal por meio da avaliação do mapa de profundidade de câmara anterior. No exame biomicroscópico sob midríase foi constatado subluxação do cristalino, sendo assim devemos estar atentos não somente aos índices tomográficos corneanos na avaliação do exame complementar e sim analisarmos outros dados importantes oferecidos pela tomografia de córnea e segmento anterior.

  8. Histiocitoma fibroso benigno profundo: achados na tomografia computadorizada e histologia Deep benign fibrous histiocytoma: computed tomography and histology findings

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    Luciano Farage

    2005-04-01

    Full Text Available Apresentamos imagens de tomografia computadorizada de um paciente de 83 anos de idade com histiocitoma fibroso benigno profundo, na face lateral da perna esquerda, com evolução de longa data. À tomografia computadorizada observamos massa bem delimitada, ovalada, e que apresentava intenso realce periférico com uso do meio de contraste iodado. Este é um tumor de partes moles pouco freqüente e com raros relatos dos seus aspectos de imagem.We present the computed tomography images of an 83-year-old male patient with a deep benign fibrous histiocytoma at the lateral aspect of the left leg. Computed tomography images showed a well-defined mass with marked peripheral enhancement by iodinated contrast medium. Only few reports of this rare soft tissue tumor can be found in the literature.

  9. Measurement and analyses of spectral noise power in computed tomography; Medida y analisis del espectro de potencias del ruido en imagenes de tomografia computarizada

    Energy Technology Data Exchange (ETDEWEB)

    Castro Tejero, P.; Garayoa Roca, J.

    2014-07-01

    Noise is an important feature of image quality. The standard deviation of pixel value in a uniform region has been frequently used as a metric to characterize noise. However, this measure does not provide any information about the noise spatial distribution. A more complete description is given by the Noise Power Spectrum (NPS) which provides both the amount and the spatial correlation of noise. The objective of the present work is to present a methodology and a computing tool to obtain the NPS, in order to analyze its components and study their behaviour for computed tomography (TC) images. Our results show that the major contribution to NPS is a random source for all the explored working conditions. The structural component is constrained to the low frequency region, where it can be as important as the random component. Moreover, we observe that the reconstruction filter and the acquisition technique, axial or helical, have a clear impact on the image noise. (Author)

  10. Tomografia de coerência óptica na commotio retinae: relato de caso Optical coherence tomography imaging in commotio retinae: case report

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    Celso Morita

    2009-08-01

    Full Text Available O objetivo deste relato é correlacionar achados à tomografia de coerência óptica e prognóstico visual de pacientes com commotio retina e de gravidades diferentes. Dois pacientes do sexo masculino, de 20 e 23 anos com baixa visual unilateral após trauma ocular contuso atribuível a edema de Berlin foram avaliados pela retinografia e tomografia de coerência óptica. A acuidade visual no olho afetado era de 20/25 no primeiro paciente e conta dedos a 2 metros no segundo. O exame oftalmológico revelou uveíte traumática e, na fundoscopia, evidenciaram-se opacificação retiniana moderada no primeiro caso e grave no segundo. A tomografia de coerência óptica confirmou discreta diminuição da depressão foveal no primeiro caso e desorganização das camadas retinianas no segundo. Houve resolução anatômica e funcional completa a tomografia de coerência óptica no primeiro paciente, enquanto o segundo evoluiu com baixa visual permanente e desorganização da arquitetura retiniana. A tomografia de coerência óptica é um exame complementar útil na avaliação do trauma retiniano, ajudando a entender sua fisiopatologia e predizer prognóstico a partir da análise anatômica da região acometida.The purpose of this case report was to correlate optical coherence tomography findings and visual outcomes of patients with different degrees of commotio retinae. A 20-year-old male and a 23-year-old male that presented with decreased vision due to Berlin's edema after blunt ocular trauma were evaluated by optical coherence tomography and retinography. The visual acuity in the affected eye was 20/25 in the first patient and counting fingers in the second one. The ophthalmic examination showed traumatic uveitis and fundoscopy revealed mild retinal opacification in the first case and severe opacification in the latter. The optical coherence tomography confirmed the reduction of foveal depression on the first case and the disarrangement of all retinal

  11. REVISIÓN DE LAS EVALUACIONES ADAPTATIVAS COMPUTARIZADAS (CAT

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    Ruber López

    2015-06-01

    Full Text Available En este artículo presentamos una revisión de las Evaluaciones Adaptativas Computarizadas. A diferencia de los test convencionales, estas evaluaciones plantean un examen adaptado a las necesidades y capacidades de cada uno de los evaluados, lo cual redunda en una mejor experiencia para el evaluado y en una mayor precisión del resultado. Las evaluaciones adaptativas se fundamentan en la teoría de respuesta a ítems, que define las directrices y condiciones para que este tipo de pruebas sea posible. A partir de esta teoría, surgen distintos modelos que permiten modelar diferentes rasgos de los evaluados y la relación de estos con la probabilidad de acertar un ítem dado. Para llevar a cabo el proceso de evaluación, un test adaptativo debe estar conformado de un banco de ítems, un método que permita la selección de estos y un criterio de terminación. Todos estos componentes articulan la prueba y la ayudan a concretarse adecuadamente. AbstractThis paper is a review of the Computerized Adaptive Testing Process. Unlike conventional tests, these assessments propose a test adapted to every examinee’s needs and capabilities, which results in a better experience for those assessed and a more accurate score. Adaptive assessments are based on item response theory, which defines the guidelines and conditions for such tests to be carried out. From this theory, different models that allow the repositioning of different traits of the examinees and their relationship with the probability to succeed in a given item, arise. To complete the assessment process, an adaptive test should consist of a set of items, a method which allows the selection of these and a termination criterion. All the aforementioned components articulate the test and help to properly materialize it.

  12. Mudanças na estrutura do solo avaliada com uso de tomografia computadorizada.

    OpenAIRE

    PIRES, L. F.; BACCHI, O. O. S.

    2010-01-01

    O objetivo deste trabalho foi avaliar, em escala milimétrica, a modificação da densidade e da porosidade de amostras deformadas de solo submetidas a ciclos de umedecimento e secamento (U-S), por meio da tomografia computadorizada de raios gama. Amostras com 98,1 cm³ foram preparadas procedendo ao peneiramento do solo em malha de 2 mm e acondicionamento de forma homogênea em tubos de PVC. As amostras de solo foram submetidas a um, dois e três ciclos de U-S. As amostras controle não foram subme...

  13. Evaluación de Lesiones Periapicales en Pacientes Derivados a Cirugía Periapical Mediante Tomografía Computarizada de Haz Cónico

    OpenAIRE

    Hernández Vigueras, Scarlette; Donoso Zúñiga, Manuel; Sanhueza Tobar, Claudio; Linco Olave, Jared; Riquelme Carrasco, Sebastián

    2017-01-01

    El uso de la tomografía computarizada de haz cónico (CBCT) en endodoncia ha ido en aumento, justificando su uso en casos más complejos, como cirugías periapicales. El objetivo fue evaluar las características imagenológicas encontradas en un grupo de pacientes derivados a cirugía periapical, mediante el uso de CBCT. Se realizó un estudio observacional descriptivo, en un grupo de pacientes, derivados a cirugía periapical, a los cuales se realizó un examen de CBCT, evaluación clínica y radiograf...

  14. Alterações no planejamento em implantodontia utilizando a tomografia computadorizada volumétrica

    OpenAIRE

    Pedroso, Ludmila Assunção de Mello

    2011-01-01

    O sucesso da reabilitação sobre implantes depende de um planejamento bem executado. Nesta fase, as características do sítio e as estruturas anatômicas adjacentes são avaliadas por meio do exame clínico e dos exames por imagem. A radiografia panorâmica é amplamente utilizada, mas recomenda-se que uma imagem seccional seja realizada. A tomografia computadorizada volumétrica (TCV) está entre os exames com maior indicação para essa avaliação. O objetivo deste trabalho foi verifi...

  15. DETERMINACIÓN DEL COLOR EN EPICARPIO DE TOMATES (LYCOPERSICUM ESCULENTUM MILL. CON SISTEMA DE VISIÓN COMPUTARIZADA DURANTE LA MADURACIÓN

    Directory of Open Access Journals (Sweden)

    Carlos Alberto Padrón Pereira

    2012-01-01

    Full Text Available Se estudió la evolución del color de muestras de tomates durante la maduración a temperatura ambiente y otras en refrigeración, mediante Sistema de Visión Computarizada (SVC. El SVC lo constituye un escenario iluminado, una cámara digital CCD y un computador (Laptop ambos calibrados. El procesamiento digital de las imágenes se llevó a cabo con el software Adobe® Photoshop® CS3 Extended, con los cuales generaron imágenes promediadas en coordenadas L*, a* y b*. La relación a*/b* y las coordenadas polares c* y hº, que presentaron diferencias estadísticas significativas entre las muestras determinadas (p<0,05.

  16. Estudio mediante tomografía computarizada de los criterios radiográficos aplicados al diagnóstico del síndrome navicular del caballo

    OpenAIRE

    Arias Sanz, Pablo

    2016-01-01

    El síndrome del navicular ha sido reconocido como una de las causas más importantes de claudicación en el caballo. En la radiografía, muchas de las lesiones del hueso navicular quedan mal definidas. Y entre ellas la pérdida de definición córtico-medular. La TC es la mejor modalidad de imagen para la valoración de las características del hueso. Pero además de la información morfológica, también proporciona información sobre la atenuación radiológica de los tejidos (tomografía computarizada cua...

  17. Lipo sarcoma in small intestine; Liposarcoma de intestino delgado

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez Iglesias, J; Pineyro Gutierrez, A; Taroco Medeiros, L; Fein Kolodny, C; Navarrete Pedocchi, H

    1987-12-01

    A case is presented by primitive liposarcoma in small intestine , an extensive bibliographical review foreigner and national in this case. It detach the exceptional of the intestinal topography of the liposarcomas; and making stress in the relative value of the computerized tomography and ultrasonography in the diagnose of the small intestine tumors . As well as in the sarcomas of another topography, chemo and radiotherapy associated to the exeresis surgery, it can be of benefit. [Spanish] Se presenta un caso de invaginacion yeyunal por liposarcoma primitivo de intestino delgado,realizandose una extensa revision bibliografica extranjera y nacional al respecto,destacando lo exepcional de la topografia intestinal de los piposarcomas; y haciendo hincapie en lo relativo valor de la tomografia computarizada y ultrasonografia en el diagnostico de los tumores de intestino delgado.Como en los sarcomas de otra topografia,la quimio y radioterapia asociadas a la cirugia de exeresis, puede ser de beneficio.

  18. Axial magnetic field produced by axially and radially magnetized permanent rings

    International Nuclear Information System (INIS)

    Peng, Q.L.; McMurry, S.M.; Coey, J.M.D.

    2004-01-01

    Axial magnetic fields produced by axially and radially magnetized permanent magnet rings were studied. First, the axial magnetic field produced by a current loop is introduced, from which the axial field generated by an infinitely thin solenoid and by an infinitely thin current disk can be derived. Then the axial fields produced by axially and by radially magnetized permanent magnet rings can be obtained. An analytic formula for the axial fields produced by two axially magnetized rings is given. A permanent magnet with a high axial gradient field is fabricated, the measured results agree with the theoretical calculation very well. As an example, the axial periodic field produced by an arrangement of alternating axially and radially magnetized rings has been discussed

  19. La tomografía computarizada en cardiopatía isquémica: de la calcificación coronaria a la caracterización tisular miocárdica

    Directory of Open Access Journals (Sweden)

    Jordi Estornell Erill

    2015-03-01

    Full Text Available Durante las últimas 2 décadas las técnicas de imagen han alcanzado un papel indispensable en prácticamente todas las enfermedades cardiovasculares. La tomografía computarizada cardiaca, en el campo de la cardiopatía isquémica, proporciona información irreemplazable para la investigación clínica y básica, y se ha convertido también en imprescindible para guiar la actitud terapéutica de los pacientes con enfermedad coronaria en la práctica diaria. Revisamos su estado actual desde la mirada de su utilidad quirúrgica.

  20. Tomografia computadorizada do cranio no diagnostico dos meningiomas: registro de 16 casos

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    James Pitagoras de Mattos

    1983-03-01

    Full Text Available Os autores se referem à importância do emprego da tomografia computadorizada do crânio para o preciso diagnóstico dos meningiomas. Constam da experiência 16 casos, comprovados cirúrgica e histologicamente. A média de idade foi de 52,1 anos, sendo 10 pacientes do sexo feminino e 6 do masculino. Quanto à localização, 5 eram da cavidade orbitrária e/ou asa do esfenóide, 3 parasagitais, 3 da foice, 2 supra-selares, 2 de convexidade e 1 do tentório. Concluem tratar-se de exame de grande positividade (95-98%, praticamente inócuo e que permite, na atualidade, o diagnóstico precoce conduzindo, consequentemente, a melhores resultados terapêuticos.

  1. Dose evaluation in diagnostic for computerized tomography; Evaluacion de dosis en diagnostico por tomografia computarizada

    Energy Technology Data Exchange (ETDEWEB)

    Flores, W.; Borges, J.C.; Mota, H. [Universidad Federal de Rio de Janeiro, PEN/COPPE/UFRJ. Caixa Postal 68509. 21945-970 Rio de Janeiro (Brazil)

    1998-12-31

    The patients which are subjected to computerized tomography tests are exposed to relatively high doses given as result doses on organs that are not matter to test. It was realized a dose levels raising in patients subjected to tests by T C, utilizing to measure this magnitude, TLD-100 thermoluminescent dosemeters which were put directly on the patient, in eye regions, thyroid, breast and navel; founding doses fluctuating between 29.10-49.39 mGy in organs examined and dose values between 0.21-29.10 mGy for organs that no matter to test. The applications of ionizing radiations in medicine do not have dose limits, but paying attention to the radiological protection optimization principle, it is recommended the use of clothes to anti-rays protection for zones not examined, getting with this to reduce the level doses as low as possible, without this to diminish the test quality. (Author)

  2. Tomografia computadorizada das patologias acometendo o compartimento iliopsoas

    Directory of Open Access Journals (Sweden)

    Montandon Cristiano

    2001-01-01

    Full Text Available Este trabalho tem como objetivo revisar as patologias que acometem o compartimento iliopsoas. Foi realizada análise retrospectiva de casos com acometimento do compartimento iliopsoas avaliados por tomografia computadorizada (TC, no Departamento de Radiologia da Faculdade de Ciências Médicas da Universidade Estadual de Campinas, nos últimos dez anos, confirmados por biópsia cirúrgica ou percutânea. Os principais diagnósticos encontrados foram neoplasias, abscessos e hematomas. Os achados tomográficos baseiam-se na extensão do acometimento iliopsoas, no grau de atenuação, margens da lesão, presença de gás e/ou calcificações, destruição óssea, infiltração da gordura e acometimento de estruturas abdominais adjacentes. A TC é o método de escolha na avaliação do compartimento iliopsoas, podendo ser utilizada para orientar biópsias percutâneas, cirúrgicas ou drenagem. Porém, os achados isolados do estudo por TC, sem o conhecimento da história clínica, não são específicos para permitir a diferenciação das diversas patologias que acometem o compartimento iliopsoas.

  3. Tomografia computadorizada e ressonância magnética nos oligodendrogliomas: correlação clínica e patológica

    Directory of Open Access Journals (Sweden)

    Simão Marcelo Novelino

    2001-01-01

    Full Text Available Oligodendrogliomas são neoplasias do tecido neuroepitelial glial originárias de oligodendrócitos. São tumores infreqüentes, responsáveis por cerca de 4% a 7% das neoplasias primárias do cérebro, predominantemente supratentoriais. O presente trabalho consistiu na avaliação dos achados de imagem pré-operatória em tomografia computadorizada e ressonância magnética e correlação clínica e patológica, levando-se em consideração a presença de tumores puros ou mistos, com componente astrocitário e o seu grau de anaplasia. O aspecto mais freqüente foi o de lesão hipodensa na tomografia computadorizada ou com hipossinal em T1 e hipersinal em T2 na ressonância magnética, podendo ter componente cístico, com pouco edema ao redor, apresentando calcificações, quase sempre grosseiras, em dois terços dos casos. Reforço após contraste ocorre em 80% dos casos, na maioria discreto.

  4. Evaluación de la disponibilidad, utilización y costos de la tomografía computarizada en el estado de Morelos, México

    Directory of Open Access Journals (Sweden)

    Pérez-Rodríguez John

    2002-01-01

    Full Text Available Objetivo. Evaluar la disponibilidad, utilización y costos económicos de la tomografía computarizada (TC en hospitales públicos y privados en el estado de Morelos, México. Material y métodos. Mediante un estudio transversal efectuado entre enero y abril de 1999, se evaluaron cuatro hospitales en el estado de Morelos, dos públicos y dos privados. Se llevaron a cabo entrevistas individuales con los directores, administradores, médicos radiólogos y jefes de mantenimiento. Se realizó un análisis estadístico descriptivo de las variables, disponibilidad, utilización y costos, así como una evaluación integral de la tomografía, haciendo énfasis en la variabilidad de los patrones observados en los hospitales participantes en el estudio. Resultados. La TC es una tecnología utilizada en los hospitales del estado de Morelos desde hace más de 10 años. Aun cuando existen programas de mantenimiento preventivo y correctivo a los equipos de tomografía, sus costos son muy elevados. Además se carece de estrategias que permitan evaluar la tecnología antes de su adquisición y durante su utilización. El estudio no incluyó aspectos relativos a la correcta indicación clínica de la TC, ni a sus posibles efectos secundarios. Conclusiones. Los hallazgos obtenidos a partir de la presente investigación fueron los siguientes: a existe una carencia de procesos de evaluación y gestión tecnológica, que permita a las unidades hospitalarias un manejo eficiente de la tomografía computarizada, y b también se carece de mecanismos para regular la adquisición, evaluar la tecnología y seleccionar las mejores alternativas en función de su efectividad, eficacia, seguridad y accesibilidad.

  5. Using axial magnetized permanent rings to build axial gradient magnetic field

    International Nuclear Information System (INIS)

    Peng Quanling

    2003-01-01

    Axial field produced by an axially magnetized permanent ring was studied. For two permanent magnet rings, if they are magnetized in the same direction, a nearly uniform axial field can be produced; if they are magnetized in opposite direction, an axial gradient field can be produced in the region between the two permanent rings, with the field strength changing from -B 0 to B 0 . A high gradient axial magnetic field has been built by using two axially magnetized permanent rings, the measured field results agree with the PANDIRA calculation very well. It is desirable that the field gradient can be varied to match various requirements. A method to produce the variable gradient field is presented. Axial gradient field can also be used as a beam focusing facility for linear accelerator if axial periodic field can be produced. Its magnetic field is similar to that of a solenoid, in which, large stray field will leak to the outside environment. A method for shielding the outside stray field is discussed

  6. Malária pulmonar: aspectos na tomografia computadorizada de alta resolução - relato de caso

    Directory of Open Access Journals (Sweden)

    Rodrigues Rosana

    2004-01-01

    Full Text Available Neste trabalho é relatado o caso de paciente do sexo masculino, de 38 anos de idade, que desenvolveu quadro de malária com comprometimento pulmonar. A tomografia computadorizada de alta resolução evidenciou espessamento de septos interlobulares e de bainhas peribroncovasculares, com áreas esparsas de atenuação em vidro fosco e de consolidações, além de derrame pleural bilateral, aspectos compatíveis com edema pulmonar. O paciente recebeu tratamento específico, evoluindo bem e tendo alta 11 dias após a internação.

  7. Neumomediastino espontáneo recidivante

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    Damaris Reyes Hernández

    2017-12-01

    Full Text Available El neumomediastino espontáneo se caracteriza por la presencia de aire en el mediastino. Es una enfermedad generalmente benigna y autolimitada, no asociada a causa directa conocida. Es de infrecuente ocurrencia. Se presenta principalmente con dolor torácico, disnea y enfisema subcutáneo. El diagnóstico se realiza sobre la base del cuadro clínico y radiografía o tomografía axial computarizada de tórax. Se presenta el caso de un paciente masculino de 17 años de edad, atleta de alto rendimiento, que comienza de forma súbita con dolor torácico, disnea y enfisema subcutáneo. Se le realizó radiografía de tórax en la que se observa la presencia de aire en el mediastino, y se corrobora el diagnóstico de neumomediastino mediante tomografía axial computarizada de tórax. Recibió tratamiento conservador con mejoría evidente. Aunque la literatura reporta que no es habitual la recurrencia, en el paciente que se presenta hubo recidiva del neumomediastino a los tres meses del primer evento. Se presenta este caso por lo infrecuente de esta enfermedad y su recurrencia.

  8. Optimization of residual heat removal pump axial thrust and axial bearing

    International Nuclear Information System (INIS)

    Schubert, F.

    1996-01-01

    The residual heat removal (RHR) pumps of German 1300 megawatt pressurized-water reactor (PWR) power plants are of the single stage end suction type with volute casing or with diffuser and forged circular casing. Due to the service conditions the pumps have to cover the full capacity range as well as a big variation in suction static pressure. This results in a big difference in the axial thrust that has to be borne by the axial bearing. Because these pumps are designed to operate without auxiliary systems (things that do not exist can not fail), they are equipped with antifriction bearings and sump oil lubrication. To minimize the heat production within the bearing casing, a number of PWR plants have pumps with combined axial/radial bearings of the ball type. Due to the fact that the maximum axial thrust caused by static pressure and hydrodynamic forces on the impeller is too big to be borne by that type of axial bearing, the impellers were designed to produce a hydrodynamic axial force that counteracts the static axial force. Thus, the resulting axial thrust may change direction when the static pressure varies

  9. Optimization of residual heat removal pump axial thrust and axial bearing

    Energy Technology Data Exchange (ETDEWEB)

    Schubert, F.

    1996-12-01

    The residual heat removal (RHR) pumps of German 1300 megawatt pressurized-water reactor (PWR) power plants are of the single stage end suction type with volute casing or with diffuser and forged circular casing. Due to the service conditions the pumps have to cover the full capacity range as well as a big variation in suction static pressure. This results in a big difference in the axial thrust that has to be borne by the axial bearing. Because these pumps are designed to operate without auxiliary systems (things that do not exist can not fail), they are equipped with antifriction bearings and sump oil lubrication. To minimize the heat production within the bearing casing, a number of PWR plants have pumps with combined axial/radial bearings of the ball type. Due to the fact that the maximum axial thrust caused by static pressure and hydrodynamic forces on the impeller is too big to be borne by that type of axial bearing, the impellers were designed to produce a hydrodynamic axial force that counteracts the static axial force. Thus, the resulting axial thrust may change direction when the static pressure varies.

  10. X-ray detectors in axial computed tomography development; Sensori di radiazioni X negli sviluppi della tomografia assiale computerizzata

    Energy Technology Data Exchange (ETDEWEB)

    Gislon, R.; Imperiali, F. [ENEA, Centro Ricerche Casaccia, Rome (Italy). Dip. Innovazione

    1996-12-01

    The increase of potentially of axial computed tomography as a non destructive investigation method in industrial field is particularly tied to the development of the X-rays detectors. The transition from the first gas ionization detectors to the last semiconductor detectors has indeed dramatically increased the performances of tomographic systems. In this report, after a quick analysis of fundamental principles of tomography, the most significant parameters for a detector to be used in a tomographic system are reviewed. The examination of the principal kinds of detectors that have been up to now used, with their working schemes, allows to delineate their characteristics and so to compare them with the ideal detector sketched above. The necessity of using high definition arrays brings to put into evidence the inadequacy of both gas and liquid ionization detectors and also of those types of light conversion devices which utilize for signal amplification a photomultiplier tube. Systems based on charge coupled devices or on a light conversion obtained with semiconductor photodiode arrays are definitely to be preferred. The progress of the last years in microelectronic technologies has brought great improvements in this field.

  11. BWR AXIAL PROFILE

    International Nuclear Information System (INIS)

    Huffer, J.

    2004-01-01

    The purpose of this calculation is to develop axial profiles for estimating the axial variation in burnup of a boiling water reactor (BWR) assembly spent nuclear fuel (SNF) given the average burnup of an assembly. A discharged fuel assembly typically exhibits higher burnup in the center and lower burnup at the ends of the assembly. Criticality safety analyses taking credit for SNF burnup must account for axially varying burnup relative to calculations based on uniformly distributed assembly average burnup due to the under-burned tips. Thus, accounting for axially varying burnup in criticality analyses is also referred to as accounting for the ''end effect'' reactivity. The magnitude of the reactivity change due to ''end effect'' is dependent on the initial assembly enrichment, the assembly average burnup, and the particular axial profile characterizing the burnup distribution. The set of bounding axial profiles should incorporate multiple BWR core designs and provide statistical confidence (95 percent confidence that 95 percent of the population is bound by the profile) that end nodes are conservatively represented. The profiles should also conserve the overall burnup of the fuel assembly. More background on BWR axial profiles is provided in Attachment I

  12. Estudo radiográfico e por tomografia computadorizada das formações orais em cães

    OpenAIRE

    Carolina de Oliveira Ghirelli

    2008-01-01

    As neoplasias orais representam a quarta neoplasia mais comum em cães. O diagnóstico por imagem das neoplasias orais é necessário para determinar a extensão do tumor e dos tecidos locais acometidos, auxiliando no prognóstico e planejamento cirúrgico. Atualmente o exame radiográfico é o método diagnóstico mais utilizado por ser mais acessível e menos oneroso, porém o grande número de estruturas no crânio e suas sobreposições dificultam adequada avaliação desta região. A tomografia computadoriz...

  13. Padronização de um método para mensuração das tábuas ósseas vestibular e lingual dos maxilares na Tomografia Computadorizada de Feixe Cônico (Cone Beam Methodology standardization for measuring buccal and lingual alveolar bone plates using Cone Beam Computed Tomography

    Directory of Open Access Journals (Sweden)

    Marcos Cezar Ferreira

    2010-02-01

    Full Text Available INTRODUÇÃO: a espessura das tábuas ósseas que recobrem os dentes por vestibular e lingual constitui um dos fatores limitantes da movimentação dentária. O avanço tecnológico em Imaginologia permitiu avaliar detalhadamente essas regiões anatômicas por meio da utilização da tomografia computadorizada de feixe cônico (TCFC. OBJETIVO: descrever e padronizar, pormenorizadamente, um método para mensuração das tábuas ósseas vestibular e lingual dos maxilares nas imagens de tomografia computadorizada de feixe cônico. METODOLOGIA: a padronização digital da posição da imagem da face deve constituir o primeiro passo antes da seleção dos cortes de TCFC. Dois cortes axiais de cada maxilar foram empregados para a mensuração da espessura do osso alveolar vestibular e lingual. Utilizou-se como referência a junção cemento-esmalte dos primeiros molares permanentes, tanto na arcada superior quanto na inferior. RESULTADOS: cortes axiais paralelos ao plano palatino foram indicados para avaliação quantitativa do osso alveolar na maxila. Na arcada inferior, os cortes axiais devem ser paralelos ao plano oclusal funcional. CONCLUSÃO: o método descrito apresenta reprodutibilidade para utilização em pesquisas, assim como para a avaliação clínica das repercussões periodontais da movimentação dentária, ao permitir a comparação de imagens pré e pós-tratamento.INTRODUCTION: The thickness of the buccal and lingual bone plates constitutes one of the limiting factors of the orthodontic movement. The imaging technology has permitted the evaluation of this anatomical region, by means of cone beam computed tomography. PURPOSE: To describe and standardize, in details, a method for measuring the buccal and lingual bone plate thickness in CBCT images. METHODOLOGY: Digital standardization of face image should constitute the first step before the selection of CBCT slices. Two axial sections of each jaw were used for measuring the thickness

  14. Axial myopathy

    DEFF Research Database (Denmark)

    Witting, Nanna; Andersen, Linda K; Vissing, John

    2016-01-01

    Classically, myopathies are categorized according to limb or cranial nerve muscle affection, but with the growing use of magnetic resonance imaging it has become evident that many well-known myopathies have significant involvement of the axial musculature. New disease entities with selective axial...

  15. Tomografia computadorizada sem contraste intravenoso no abdome agudo: quando e por que usar When and why use unenhanced computed tomography in patients with acute abdomen

    Directory of Open Access Journals (Sweden)

    Edison de Oliveira Freire Filho

    2006-02-01

    Full Text Available A tomografia computadorizada sem contraste intravenoso tem sido freqüentemente proposta na avaliação inicial de pacientes com suspeita de abdome agudo, ocupando o espaço de outros métodos diagnósticos. Os autores apresentam uma revisão bibliográfica dos principais aspectos e eficácia da tomografia computadorizada sem contraste intravenoso no diagnóstico de apendicite aguda, cólica nefrética, diverticulite, pancreatite aguda, apendicite epiplóica, pneumoperitônio e obstrução intestinal. Discutem quais as vantagens e limitações desta técnica de exame, bem como seus aspectos práticos.The use of unenhanced computed tomography has been frequently recommended for the initial assessment of patients with clinical suspicion of acute abdomen instead of other diagnostic methods. The authors present a review of the literature on the main aspects, advantages, limitations and efficacy of unenhanced computed tomography for the diagnosis of acute appendicitis, renal colic, diverticulitis, acute pancreatitis, primary epiploic appendicitis, pneumoperitoneum and small bowel obstruction. The advantages and limitations of this technique are also discussed.

  16. Detection of diabetic foveal edema with biomicroscopy, fluorescein angiography and optical coherence tomography Detecção do edema foveal diabético com biomicroscopia, angiografia fluoresceínica e tomografia de coerência óptica

    Directory of Open Access Journals (Sweden)

    Rosana Zacarias Hannouche

    2008-10-01

    Full Text Available To describe different techniques for the detection of diabetic foveal edema. A retrospective review of the detection of diabetic foveal edema. Noncontact lens biomicroscopy is relatively insensitive in mild foveal thickening apparent on optical coherence tomography. Optical coherence tomography measurements can detect early retinal damage in diabetic retinopathy patients.Descrever diferentes técnicas para detecção do edema foveal diabético. Uma revisão da detecção do edema foveal diabético. Biomicroscopia com lente de não contato é relativamente insensível em edema leve aparente na tomografia de coerência óptica. Tomografia de coerência óptica pode detectar precocemente o dano retiniano inicial em pacientes com retinopatia diabética.

  17. Trauma dos ossos temporais e suas complicações: aspectos na tomografia computadorizada

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    Ana Maria Doffémond Costa

    2013-04-01

    Full Text Available A maioria das fraturas dos ossos temporais resulta de traumas cranianos bruscos, de alta energia, estando muitas vezes relacionadas a outras fraturas cranianas ou a politraumatismo. As fraturas e os deslocamentos da cadeia ossicular, na orelha média, representam umas das principais complicações das injúrias nos ossos temporais e, por isso, serão abordadas de maneira mais profunda neste artigo. Os outros tipos de injúrias englobam as fraturas labirínticas, fístula dural, paralisia facial e extensão da linha de fratura ao canal carotídeo. A tomografia computadorizada tem papel fundamental na avaliação inicial dos pacientes politraumatizados, pois é capaz de identificar injúrias em importantes estruturas que podem causar graves complicações, como perda auditiva de condução ou neurossensorial, tonturas e disfunções do equilíbrio, fístulas perilinfáticas, paralisia do nervo facial, lesões vasculares, entre outras.

  18. Tumores intracraneales: hallazgos tomográficos más frecuentes

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    José Antonio Navarro Mariño

    2015-12-01

    Full Text Available La Tomografia Axial Computarizada (TAC es la técnica de neuroimagen más ampliamente utilizada para el diagnóstico de los tumores intracraneales. Se ha estimado que con este estudio  se pueden  detectar hasta el 90% de las neoplasias intracraneales. En tal sentido se realizó un estudio descriptivo, retrospectivo en 24 pacientes atendidos en el Hospital Pediátrico Provincial “Octavio de la Concepción y la Pedraja” de Holguín,  con diagnóstico de tumores  intracraneales, en el período comprendido de enero 2006 a diciembre 2011, a los cuales  se les realizó TAC   de cráneo, con el objetivo de describir los hallazgos tomográficos más incidentes.  Se tomaron en consideración la edad, sexo, tipo  histológico, hallazgos tomográficos directos e indirectos y la localización tumoral. Se encontró que los tumores intracraneales se presentaron más frecuentemente en pacientes entre los 5 y 9 años, predominando  el sexo masculino. Los Astrocitomas fueron los más representados (62.5%. Como  hallazgos tomográficos indirectos  predominaron la dilatación ventricular (62.5% y  el  efecto de masa (58.3%. El 66.6% presentó  localización infratentorial intraaxial. La mayoría  de las lesiones  se observaron hipodensas  y homogéneas. Se recomendó  evaluar la correlación entre los tipos histológicos y los hallazgos imagenológicos, para su posible empleo como guías  para el diagnóstico.

  19. Lipoma Pericárdico: presentación de un caso

    Directory of Open Access Journals (Sweden)

    Raysa Peñalver Valido

    2013-12-01

    Full Text Available Introducción: los tumores cardíacos primarios son raros. Según diferentes estudios de necropsias su incidencia varía del 0,001% al 0,28% y en su mayoría (75% revisten carácter benigno; los lipomas representan el 8,4 % entre todos los tumores cardiacos primarios. Presentación de caso: paciente masculino de la raza blanca de 62 años de edad, fumador, con antecedentes de Asma Bronquial Grado II, el cual acude a consulta en el policlínico Pedro Borrás Astorga de La Palma en Octubre de 2012 refiriendo disnea a los esfuerzos, de dos meses de evolución y tos seca ocasional. No se recogieron datos de interés al examen físico del sistema respiratorio ni cardiovascular. Se le realizan complementarios que incluyó rayos X de tórax visualizando lesión radiopaca en ángulo cardiofrénico derecho por lo que se indica Tomografía Axial Computarizada Multicorte de Tórax que muestra imagen de muy bajas densidades ubicada en relación con pericardio parietal que resultó ser un lipoma pericárdico. Conclusiones: la Tomografía Axial Computarizada Multicorte constituye un examen indispensable para el diagnóstico pues muestra con alta especificidad localización, dimensión y densidad.

  20. Quistes de los maxilares

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    Ivan Alberto Manotas Arevalo

    2013-12-01

    Full Text Available Los Grandes Quistes de los Maxilares han estado vinculados siempre a la humanidad, desde tiempos remotos, pues han sido halladas en restos de especimenes fosiles, han llamado la atencion de los clínicos, en torno a su etiologia, en la que se ha introducido la participacion de la genetica, (demostrada en el desarrollo de los queratoquistes maxilares, la fisiopatologia, caracteristicas histologicas (inmunohistoquimica, posibilidades diagnosticas por la imagen, (como la tomografia computarizada y la resonancia nuclear magnetica y otras pruebas. Además llaman la atención al estudio, por sus alternativas de manejo especialmente las formas radicales, y el analisis de asociaciones a otras patolo-gias benignas y malignas, y de la recurrencia muy alto de algunas de estas lesiones. Mucho se ha desarrollado para elucidar su naturaleza real, estadificar adecuadamente la lesion descartando asocia-ciones patologicas sindromicas, indicar un tratamiento apropiado, y realizar seguimientos a largo plazo. Este articulo pretende recaudar una information general que de parametros para abordar el estudio de los quistes maxilares a partir de la presentacion de un caso clinico.

  1. Tumores intracranianos em pacientes encaminhados para estudos por tomografia de coerência óptica como portadores de glaucoma sem hipertensão ocular: relato de dois casos Intracranial tumors in patients referred for optical coherence tomography examination as glaucoma suspects: case report

    Directory of Open Access Journals (Sweden)

    Laurentino Biccas Neto

    2009-10-01

    Full Text Available A tomografia de coerência óptica (OCT tem se mostrado muito útil na avaliação de pacientes com glaucoma. São relatadas duas pacientes referidas com a suspeita de glaucoma sem hipertensão para avaliação por tomografia de coerência óptica que, na verdade, eram portadoras de tumores intracranianos - um cordoma de clivo no primeiro caso e um craniofaringeoma no segundo. Os achados à tomografia de coerência óptica - diminuição difusa da espessura da camada de fibras nervosas circumdiscais desproporcionalmente acentuada nos setores nasal e temporal - levantaram a suspeita de acometimento na região do quiasma e permitiram o diagnóstico destes importantes tumores intracranianos.Optical coherence tomography (OCT has proved to be a very valuable tool in the assessment of patients with glaucoma. In this report, intracranial tumors were discovered in two glaucoma suspects referred for diagnostic confirmation by OCT - a clivus chordoma and a craniopharyngeoma. Optical coherence tomography findings - marked asymmetrical diffuse attenuation of the peripapillary nerve fiber layer in nasal and temporal sectors - raised concerns about lesions in chiasmatic region and permitted the timely diagnosis of these intraocular tumors.

  2. Anatomic considerations for C2 pedicle screw placement: the use of computerized tomography measurements Consideraciones anatómicas de la cocalización de los tornillos pediculares en C2: uitlización de las medidas de la tomografia computadorizada Considerações anatômicas sobre a localização dos parafusos pediculares em C2: utilização das medidas da tomografia computadorizada

    Directory of Open Access Journals (Sweden)

    Adebukoa Onibokun

    2009-03-01

    eje del pedículo y el ángulo transverso del pedículo (ángulo entre el eje del pedículo y la línea media del cuerpo vertebral. RESULTADOS: el valor promedio del ancho pedicular fue de 5.8 1.2mm. En el sexo masculino el valor promedio del ancho del pedículo (6.0 1.3mm fue mayor comparado con el sexo femenino (5.6 1.1mm, sin embargo no fue observada una diferencia estadística. El valor promedio del ángulo transverso del pedículo fue de 43.9 3.9 grados, siendo de 43.2 3.8 grados en el sexo masculino y 44.7 3.7 grados en el sexo femenino. CONCLUSIÓN: la proyección y determinación en el periodo preoperatorio de las dimensiones anatómicas del pedículo C2 son importantes para la determinación de la trayectoria y dimensiones del local donde el implante será colocado.OBJETIVO: o conhecimento detalhado das características anatômicas do pedículo de C2 é necessário para minimizar os riscos relacionados com a colocação dos parafusos. O objetivo deste trabalho é avaliar as medidas lineares e angulares do eixo axial verdadeiro do pedículo de C2 utilizando tomografia computadorizada. MÉTODOS: foram utilizadas tomografias computadorizadas axiais de 93 pacientes (47 do sexo masculino e 46 do sexo feminino com média de idade de 48 anos. As imagens axiais do pedículo de C2 foram selecionadas para o estudo e os parâmetros estudados foram: largura do pedículo (diâmetro mediolateral do istmo do pedículo perpendicular ao eixo do pedículo e o ângulo tranverso do pedículo (ângulo entre o eixo do pedículo e a linha média do corpo vertebral. RESULTADOS: o valor médio da largura do pedículo foi 5,81,2mm. Nos pacientes de sexo masculino o valor médio da largura do pedículo (6,01,3mm foi maior que nos pacientes de sexo feminino (5,61,1mm. No entanto, não foi observada diferença estatística. O valor médio do ângulo transverso do pedículo foi de 43,93,9 graus, sendo de 43,23,8 graus no sexo masculino e 44,73,7 graus no sexo feminino. CONCLUSÃO: o

  3. Complicações pulmonares após uso de crack: achados na tomografia computadorizada de alta resolução do tórax Pulmonary complications of crack cocaine use: high-resolution computed tomography of the chest

    Directory of Open Access Journals (Sweden)

    Alexandre Mançano

    2008-05-01

    Full Text Available Relatamos os achados na tomografia computadorizada de alta resolução de um paciente que, após uso de cocaína fumada (crack, desenvolveu quadro de hemoptise, dispnéia e dor torácica súbitas. As radiografias de tórax mostravam consolidações predominando em lobos superiores. A tomografia de alta resolução evidenciava opacidades em vidro fosco, consolidações e nódulos do espaço aéreo. Nova tomografia de controle, após suspensão da droga e uso de corticóides, mostrou regressão parcial das lesões e aparecimento de escavações. A correlação entre os achados clínicos, laboratoriais e de imagem permitiu o diagnóstico de "pulmão de crack".Here, we report high-resolution computed tomography (HRCT findings in a patient who developed sudden hemoptysis, dyspnea and chest pain after smoking crack cocaine. Chest X-rays showed consolidations, primarily in the upper lobes, and HRCT scans showed ground glass attenuation opacities, consolidations and air-space nodules. A follow-up CT, after drug use discontinuation and administration of corticosteroids, showed partial resolution of pulmonary lesions and the appearance of cavitations. Clinical, imaging and laboratory findings led to a diagnosis of 'crack lung'.

  4. Paracoccidioidomicose pulmonar: relato de caso clínico com aspetos em tomografia computorizada de alta resolução

    Directory of Open Access Journals (Sweden)

    M. Armas

    2012-07-01

    Full Text Available Resumo: A Paracoccidioidomicose é uma micose sistémica endémica nas áreas rurais da América Latina, uma fonte importante de imigrantes e destino de emigração e turismo europeu, a maioria dos casos ocorrendo no Brasil, Argentina, Venezuela e Colômbia. Os autores descrevem o caso clínico de um paciente com 43 anos, anteriormente emigrado na Venezuela e residente em Portugal há 8 anos, que se apresenta com lesão cutânea isolada. Embora sem queixas relevantes do foro respiratório, apresentava extensas lesões do parênquima pulmonar caracterizadas por tomografia computorizada de alta resolução (TCAR. Foi realizada biópsia da lesão cutânea e exame micológico da expetoração que revelaram infeção por Paracoccidioides brasiliensis (PB. Abstract: Paracoccidioidomycosis is a systemic mycosis which is endemic in rural areas of Latin America, an important European source of immigrants and a growing European touristic destination as well, with most cases occurring in Brazil, Argentina, Venezuela and Colombia. The authors report a case of a 43 year old man who previously worked in Venezuela and is living in Portugal for 8 years, presenting with a single cutaneous lesion. Despite the absence of valuable respiratory complaints, severe lung damage was found with high-resolution computed tomography (HRCT. Biopsy of the cutaneous lesion and mycologic sputum examination were performed revealing Paracoccidioides brasiliensis infection. Palavras-chave: Paracoccidioidomicose, Paracoccidioides brasiliensis, Fibrose pulmonar, Tomografia computorizada de alta resolução, Keywords: Paracoccidioidomycosis, Paracoccidioides brasiliensis, Pulmonary fibrosis, High-resolution computed tomography

  5. Apendicite aguda: achados na tomografia computadorizada - ensaio iconográfico Acute appendicitis: computed tomography findings - an iconographic essay

    Directory of Open Access Journals (Sweden)

    Marcelo Eustáquio Montandon Júnior

    2007-06-01

    Full Text Available A apendicite aguda é a causa mais comum de dor abdominal aguda que requer intervenção cirúrgica no mundo ocidental. O diagnóstico precoce é essencial para minimizar a morbidade da doença. O uso dos métodos de imagem significou grande avanço no diagnóstico desta entidade, até então avaliada apenas com base na história clínica, exame físico e dados laboratoriais, haja vista que 20% a 33% dos pacientes apresentam sintomas atípicos. O diagnóstico é mais difícil nas crianças, nos idosos e nas mulheres em idade fértil. Os principais métodos de imagem para sua avaliação são a ultra-sonografia e a tomografia computadorizada. Os objetivos deste trabalho são: descrever a fisiopatologia da doença, comentar os principais aspectos técnicos da tomografia computadorizada, demonstrar e ilustrar os achados tomográficos e citar os principais diagnósticos diferenciais.Acute appendicitis is the most important cause of abdominal pain requiring surgical intervention in the Western world. The early diagnosis of this disease is of paramount relevance for minimizing its morbidity. Imaging methods have represented a huge progress in the diagnosis of this entity, which used to be based essentially on clinical history, physical examination and laboratory tests results, considering that 20% to 33% of patients present with atypical symptoms. Diagnostic difficulty is higher in children, the elderly, and women in childbearing age. The main imaging methods for evaluation of acute appendicitis are ultrasound and computed tomography. The present study is aimed at describing the disease physiopathology, commenting main computed tomography technical aspects, demonstrating and illustrating tomographic findings, and describing main differential diagnoses.

  6. Computed Tomography findings in Fournier's gangrene; Hallazgos en tomografia computarizada de la grangrena de Fournier

    Energy Technology Data Exchange (ETDEWEB)

    Isusi, M.; Campo, M.; Oleaga, L.; Grande, J.; Grande, D. [Hospital de Barsurto. Bilbao (Spain)

    2000-07-01

    To assess the utility of computed tomography (CT) as an imaging technique in the diagnosis and determination of the extension of Fournier's gangrene (FG). We report the cases of six patients who had been clinically diagnosed as having FG, CT, enhanced by oral and intravenous contrast media, was performed in all the patients. All six patients presented soft tissue masses and gas in the scrotal region, which were also detected in the perineal region in five. In two patients, the gas extended toward anterior abdominal wall and in one of them, it also observed in anterior and posterior para renal space. The major predisposing factors were diabetes and alcoholism and the most common triggering factor was urologic disease. CT confirms the existence of FG and aids in assessing its extension and, in some cases, in identifying the underlying cause. (Author) 15 refs.

  7. Estudo do metabolismo da glicose na tuberculose pulmonar ativa utilizando a tomografia por emissão de pósitrons (18F-FDG PET Evaluation of glucose metabolism in active lung tuberculosis by positron-emission tomography (18F-FDG PET

    Directory of Open Access Journals (Sweden)

    SIDNEY BOMBARDA

    2002-09-01

    Full Text Available Os métodos de imagem utilizados na avaliação da tuberculose pulmonar incluem a radiografia e a tomografia computadorizada do tórax. As imagens obtidas pelos métodos de medicina nuclear permitem estudos funcionais e metabólicos dos órgãos de interesse, através do uso de radiofármacos específicos. Alterações do metabolismo da glicose podem ser detectadas pela tomografia por emissão de pósitrons (PET utilizando-se o 18F-fluorodesoxiglicose (18F-FDG. Essas alterações estão presentes nas doenças neoplásicas, inflamatórias e infecciosas. A tuberculose é uma doença granulomatosa causada pelo Mycobacterium tuberculosis, que se utiliza de glicose como fonte de energia. Objetivo: O estudo do metabolismo da glicose na tuberculose pulmonar através da PET e sua comparação com a tomografia computadorizada de tórax. Material e métodos: Foram avaliados 20 pacientes portadores de tuberculose pulmonar. Todos foram submetidos à PET e à tomografia computadorizada de tórax, em até 30 dias após o início do tratamento. Resultados: Todos os pacientes apresentaram captação positiva do 18F-FDG na PET. Na tomografia computadorizada do tórax, todos os pacientes apresentaram sinais compatíveis com atividade de tuberculose. A sensibilidade dos dois métodos foi de 100%. Houve concordância entre os achados do 18F-FDG PET e da tomografia computadorizada (K = 0,27 e p Current methods to evaluate lung tuberculosis include chest radiography and computed tomography. Nuclear medicine imaging techniques are performed after administration of specific radiopharmaceuticals that accumulate in the organs of interest. Alterations of glucose metabolism can be observed by positron-emission tomography, using 18F-fluorodeoxyglucose (18F-FDG PET. These findings are present in the neoplasms, but also in inflammatory and infectious diseases. Tuberculosis is a granulomatous disease caused by Mycobacterium tuberculosis , that uses glucose as an energy source

  8. Avaliação do edema macular após cirurgia não complicada de facoemulsificação com implante de lente intraocular por meio da tomografia de coerência óptica spectral domain

    Directory of Open Access Journals (Sweden)

    Everton Paroschi Corrêa

    2013-12-01

    Full Text Available OBJETIVO: Avaliar o edema macular após cirurgia não complicada de facoemulsificação com implante de lente intraocular por meio da tomografia de coerência óptica spectral domain (OCT-SD. MÉTODOS: Foi realizado estudo prospectivo em 62 olhos de pacientes submetidos à facoemulsificação com implante de lente intraocular. Os pacientes foram avaliados antes e após a cirurgia, no primeiro dia, e na primeira, segunda e quarta semanas. Acuidade visual (AV, células na câmara anterior e tomografia de coerência óptica macular cubo 200x200 foram medidos. RESULTADOS: Após a cirurgia de facoemulsificação houve melhora da acuidade visual, inflamação decrescente, e a espessura e o volume macular aumentaram. Ocorreu um caso de edema macular cistoide. Houve correlação inversa fraca entre a acuidade visual e a espessura macular central, e entre a acuidade visual e o volume macular. Foi observada correlação direta fraca entre a inflamação e o volume macular. CONCLUSÃO: Edema macular subclínico desenvolve-se mesmo após cirurgia de catarata não complicada em pacientes não predispostos. A tomografia de coerência óptica spectral domain foi capaz de detectar pequenos aumentos na espessura macular no período avaliado.

  9. Quiste sinovial en articulación interapofisaria lumbar. Una causa infrecuente de lumbociática

    OpenAIRE

    Villas, C. (Carlos); Leyes, M. (Manuel)

    1997-01-01

    Los quistes sinoviales de las articulaciones facetarias pueden ser asintomáticos o provocar dolor lumbar, con o sin clínica radicular. Se considera que son secundarios a traumatismos o a degeneración articular, y ocurren con mayor frecuencia en pacientes con espondi lolistesis. El diagnóstico se establece con la tomografía axial computarizada o la resonancia magnética, que mues tran una lesión quísti ca adyacente a la faceta articu lar. Realizamos una revis...

  10. Computerised Axial Tomography (CAT)

    Science.gov (United States)

    1990-06-01

    Ministry of’ Defence, Defence Research Information Centre, UK. Computerised Axial Tomography ( CAT ) Report Secufty C"uMiauion tide Onadtiicadon (U. R, Cor S...DRIC T 8485 COMPUTERISED AXIAL TOMOGRAPHY ( CAT ) F.P. GENTILE, F. SABETTA, V. TRO1* ISS R 78/4.Rome, 1.5 Mlarch 1978 (from Italian) B Distribution(f...dello Radiazioni ISSN 0390--6477 F.P. GENTILE, F. SABETTA. V. TROI Computerised Axial Tomography ( CAT ) March 15, 1978). This paper is a review of

  11. Correlación neuropsicológica y electrofisiológica en niños escolares con TCE

    OpenAIRE

    Abel Delgado; Luis Quintanar; Yulia Solovieva; Regina Machinskaya

    2011-01-01

    El traumatismo craneoencefálico (TCE) es una de las causas principales por la que se solicita atención médica en el servicio hospitalario de urgencias. El TCE frecuentemente produce daño cerebral o deterioro funcional del sistema nervioso en distintos niveles, que se refleja en las funciones cognitivas, tanto en niños como en adultos. El objetivo del presente estudio es correlacionar los resultados obtenidos a través de la Tomografía Axial Computarizada (TAC), el registro electroencefalográfi...

  12. Paciente con tumor de cuerpo carotideo

    Directory of Open Access Journals (Sweden)

    Mariuska Forteza Sáez

    Full Text Available Los tumores de cuerpo carotideo (paragangliomas son neoplasias altamente vascularizadas, muy poco frecuentes y generalmente benignas, originadas en los quimiorreceptores del cuerpo carotideo. Se presenta el caso de un paciente de 54 años, con aumento de volumen cervical derecho, asintomático, con estudio preoperatorio y angiografía realizados por tomografía axial computarizada, que resultan compatibles con tumor de cuerpo carotideo. Se realiza disección subadventicial, informando la biopsia paraganglioma. El tumor fue completamente resecado, sin evidencia de recurrencia y sin complicaciones.

  13. Tomografia computadorizada em pacientes portadores de neurocisticercose com hipertensão intracraniana por hidrocefalia obstrutiva: comparação com ventriculografia com Dimer-X

    Directory of Open Access Journals (Sweden)

    Benedicto Oscar Colli

    1984-06-01

    Full Text Available Estudo das alterações observadas nas tomografias computadorizadas (TCs de 16 casos de neurocisticercose, com hipertensão intracraniana por hidrocefalia. Todos os casos foram submetidos a radiografias simples do crânio e 12, à ventriculografia com Dimer-X. Nas radiografias simples foram observados sinais de hipertensão intracraniana em 7, calcificações em um, e d foram normais. A TC mostrou parênquima cerebral normal em 9 casos e nos 7 restantes áreas hipodensas arredondadas de tamanho variado, com ou sem retenção de contraste na periferia, e/ou calcificações esparsas no parenquima. Hidrocefalia foi a única alteração observada no sistema ventricular nos casos em que o exame foi realizado previamente à derivação do LCR. As ventriculografias foram analisadas em trabalho anterior e permitiram localizar e determinar as características da obstrução e a presença de massas ocupando espaço dentro dos ventrículos. A comparação das ventriculografias e TCs realizadas na mesma época evidenciou que a primeira fornece melhores informações sobre o sistema ventricular mas, por outro lado, a tomografia fornece informações adicionais sobre o parênquima cerebral. A TC e a ventriculografia são exames que se completam na avaliação e no diagnóstico destes pacientes.

  14. A tomografia computadorizada de alta resolução na avaliação da toxicidade pulmonar por amiodarona High-resolution computed tomography of amiodarone pulmonary toxicity

    Directory of Open Access Journals (Sweden)

    Daniela Peixoto Consídera

    2006-04-01

    Full Text Available OBJETIVO: Avaliar as principais alterações identificadas na tomografia computadorizada de alta resolução do tórax em pacientes com toxicidade pulmonar pela amiodarona. MATERIAIS E MÉTODOS: Foram avaliadas dez tomografias computadorizadas de alta resolução de tórax de pacientes com pneumonite pela amiodarona, seis desses pacientes do sexo masculino e quatro do sexo feminino, com idade média de 73,5 anos. RESULTADOS: Os achados tomográficos mais relevantes foram opacidades lineares ou reticulares em seis casos (60%, pequenos nódulos com densidade elevada em seis casos (60%, consolidações densas em três casos (30% e aumento da densidade do parênquima hepático em cinco de oito casos em que havia estudo tomográfico do abdome superior (62,5%. CONCLUSÃO: A tomografia computadorizada de alta resolução é um exame importante na avaliação de pacientes com toxicidade pulmonar pela amiodarona, devendo ser realizada sempre que houver suspeita deste diagnóstico. O achado de espessamento de septos interlobulares associado a lesões com aumento de densidade é altamente sugestivo deste diagnóstico.OBJECTIVE: To evaluate the main findings of chest high-resolution computed tomography in patients with amiodarone pulmonary toxicity. MATERIALS AND METHODS: Ten patients - six male and four female, average age of 73.5 years - with amiodarone-induced pneumonitis have undergone chest high-resolution computed tomography. RESULTS: The most relevant tomographic findings were linear or reticular opacities in six cases (60%, small high density nodules in six cases (60%, dense consolidations in three cases (30% and increased density in the hepatic parenchyma in five of eight cases in which there was a superior abdomen CT scan (62.5%. CONCLUSION: The high-resolution computed tomography is a valuable non-invasive test for evaluating patients with amiodarone pulmonary toxicity and should always be performed when one suspects of the presence of this

  15. Resolution of axial shear strain elastography

    International Nuclear Information System (INIS)

    Thitaikumar, Arun; Righetti, Raffaella; Krouskop, Thomas A; Ophir, Jonathan

    2006-01-01

    The technique of mapping the local axial component of the shear strain due to quasi-static axial compression is defined as axial shear strain elastography. In this paper, the spatial resolution of axial shear strain elastography is investigated through simulations, using an elastically stiff cylindrical lesion embedded in a homogeneously softer background. Resolution was defined as the smallest size of the inclusion for which the strain value at the inclusion/background interface was greater than the average of the axial shear strain values at the interface and inside the inclusion. The resolution was measured from the axial shear strain profile oriented at 45 0 to the axis of beam propagation, due to the absence of axial shear strain along the normal directions. The effects of the ultrasound system parameters such as bandwidth, beamwidth and transducer element pitch along with signal processing parameters such as correlation window length (W) and axial shift (ΔW) on the estimated resolution were investigated. The results show that the resolution (at 45 0 orientation) is determined by the bandwidth and the beamwidth. However, the upper bound on the resolution is limited by the larger of the beamwidth and the window length, which is scaled inversely to the bandwidth. The results also show that the resolution is proportional to the pitch and not significantly affected by the axial window shift

  16. Signatures for axial chromodynamics

    International Nuclear Information System (INIS)

    Pati, J.C.

    1978-07-01

    Within the context of basic left-right symmetry and the hypothesis of unification of weak, electromagnetic and strong forces at a mass level approximately equal to 10 4 -10 6 GeV, relatively light ''mass'' axial gluons, confined or liberated, must be postulated. The authors remark that the existence of such ''light'' axial gluons supplementing the familiar vector octet preserves the successes of QCD, both for deep inelastic processes and charmonium physics. Through the characteristic spin-spin force, generated by their exchange, they may even help resolve some of the discrepancies between vector QCD predictions and charmonium physics. The main remark of this note is that if colour is liberated, not only vector but also axial-vector gluons are produced in high-energy e - e + experiments, e.g. at PETRA and PEP, with fairly large cross-section. Distinctive decay modes of such liberated axial gluons are noted

  17. A new strategy of axial power distribution control based on three axial offsets concept

    International Nuclear Information System (INIS)

    Shimazu, Yoichiro

    2009-01-01

    We have proposed a very simple control procedure for axial xenon oscillation control based on a characteristic trajectory. The trajectory is drawn by three offsets of power distributions, namely, AOp, AOi and AOx. They are defined as the offset of axial power distribution, the offset of the power distribution under which the current iodine distribution is obtained as the equilibrium and that for xenon distribution, respectively. When these offsets are plotted on X-Y plane for (AOp-AOx, AOi-AOx) the trajectory draws a quite characteristic ellipse (or an elliptic spiral). On the other hands, Constant Axial Offset Control (CAOC) procedure is adopted as axial power distribution control strategy during both base load and load following operations in domestic PWRs. In the previous paper, we have presented an innovative procedure of axial power distribution control during load following in PWRs based on this trajectory such that the AOp-AOx is to be controlled to zero when the value deviates the pre-determined limiting values. In this paper we propose a modified control strategy to get more stability of axial power distributions. In this strategy, we control the trajectory to be close to the major axis of the ellipse when the power distribution reaches the limiting values. In other words, the plot is not controlled only to reduce AOp-AOx but also AOi-AOx is taken into account at the same time. It is known that when the plot is controlled to the major axis, it means that the point gives the peak position of axial xenon oscillation. Therefore xenon oscillation will not increase its amplitude any more. Thus more stable axial power distribution control is attained. This kind of design concept is quite important especially for the future PWRs with elongated fuel length and longer core life. Because in a longer effective core and also the longer core life, it has been known that the stability of axial xenon oscillation becomes more unstable. In this paper, some simulation

  18. Modernity: A new axial (era culture?

    Directory of Open Access Journals (Sweden)

    Wolfgang Schluchter

    2017-10-01

    Full Text Available The proposition of an axial age, lasting roughly from 800 to 200 B.C. and occurring in major civilizations (China, India, Near East independent of each other, first introduced by Alfred Weber and Karl Jaspers, then further developed by Robert Bellah and S. N. Eisenstadt among others, implied from the outset the question whether there has been a second axial age, leading to modernity, and if so, whether this second axial age consists in a secularization of the achievements of the first axial age. In this article it is argued that the notion of a second axial age is meaningful, but that the emergence of modernity can›t be accounted for in terms of secularization of the achievements of the first axial age. Rather, a new axial principle was institutionalized which separates the modern from the premodern world. This new principle is spelled out with reference to Hans Blumenberg, Charles Taylor and especially Max Weber. The emphasis is on the dialectics of disenchantment and the place of religion in a secular age

  19. Experimental Studies on Strength Behaviour of Notched Glass/Epoxy Laminated Composites under Uni-axial and Bi-axial Loading

    Science.gov (United States)

    Guptha, V. L. Jagannatha; Sharma, Ramesh S.

    2017-11-01

    The use of FRP composite materials in aerospace, aviation, marine, automotive and civil engineering industry has increased rapidly in recent years due to their high specific strength and stiffness properties. The structural members contrived from such composite materials are generally subjected to complex loading conditions and leads to multi-axial stress conditions at critical surface localities. Presence of notches, much required for joining process of composites, makes it further significant. The current practice of using uni-axial test data alone to validate proposed material models is inadequate leading to evaluation and consideration of bi-axial test data. In order to correlate the bi-axial strengths with the uni-axial strengths of GFRP composite laminates in the presence of a circular notch, bi-axial tests using four servo-hydraulic actuators with four load cells were carried out. To determine the in-plane strength parameters, bi-axial cruciform test specimen model was considered. Three different fibre orientations, namely, 0°, 45°, and 90° are considered with a central circular notch of 10 mm diameter in the present investigation. From the results obtained, it is observed that there is a reduction in strength of 5.36, 2.41 and 13.92% in 0°, 45°, and 90° fibre orientation, respectively, under bi-axial loading condition as compared to that of uni-axial loading in laminated composite.

  20. Stall inception and warning in a single-stage transonic axial compressor with axial skewed slot casing treatment

    International Nuclear Information System (INIS)

    Lim, Byeung Jun; Kwon, Se Jin; Park, Tae Choon

    2014-01-01

    Characteristic changes in the stall inception in a single-stage transonic axial compressor with an axial skewed slot casing treatment were investigated experimentally. A rotating stall occurred intermittently in a compressor with an axial skewed slot, whereas spike-type rotating stalls occurred in the case of smooth casing. The axial skewed slot suppressed stall cell growth and increased the operating range. A mild surge, the frequency of which is the Helmholtz frequency of the compressor system, occurred with the rotating stall. The irregularity in the pressure signals at the slot bottom increased decreasing flow rate. An autocorrelation-based stall warning method was applied to the measured pressure signals. Results estimate and warn against the stall margin in a compressor with an axial skewed slot.

  1. Characterization of Multiflux Axial Compressors

    International Nuclear Information System (INIS)

    Brasnarof, Daniel; Kyung Kyu-Hyung; Rivarola, Martin; Gonzalez Jose; Florido, Pablo; Orellano, Pablo; Bergallo, Juan

    2003-01-01

    In the present work the results of analytical models of performance are compared with experimental data acquired in the multi flux axial compressor test facility, built in The Pilcaniyeu Technological Complex for the SIGMA project.We describe the experimental circuit and the data of the dispersion inside the axial compressor obtained using a tracer gas through one of the annular inlets.The attained results can be used to validate the design code for the multi flux axial compressors and SIGMA industrial plant

  2. FIBROSIS PULMONAR IDIOPÁTICA

    OpenAIRE

    Álvaro Undurraga P., DR.

    2015-01-01

    La FPI predomina en el sexo masculino, en edades avanzadas, con tos y/o disnea progresivas. Un 5% se presenta como una forma familiar. La tomografía axial computarizada de tórax, fundamental en el diagnóstico, en al menos un 50% hace innecesaria la biopsia. El diagnóstico es conjunto con clínicos, radiólogos y patólogos. La sobrevivencia media es de tres a cinco años desde el diagnóstico. La historia natural es un deterioro progresivo, pero hay formas rápidas y también pueden aparecer e...

  3. Mixoma ventricular izquierdo

    Directory of Open Access Journals (Sweden)

    Camilo Alvarado-Castro

    2017-05-01

    Conclusión: Las neoplasias cardiacas son infrecuentes siendo el mixoma, el tumor benigno más común del corazón. El diagnóstico puede ser sugerido por los síntomas, aunque es usual encontrar un examen físico normal. Se diagnóstica con el ecocardiograma transtorácico, la tomografía axial computarizada y la resonancia nuclear magnética. El tratamiento es quirúrgico, siendo seguro, efectivo y considerado curativo en la mayoría de las resecciones, con una tasa de supervivencia a 5 años del 83%.

  4. Gunshot wounds to the head. Correlations between CT and clinical findings, neurosurgical treatment and long-term sequels; Traumi cranio-encefalici da proiettile: correlazione tra tomografia computerizzata, clinica, trattamento neurochirurgico e sequele a distanza

    Energy Technology Data Exchange (ETDEWEB)

    Salzano, A.; Nocera, V. [Ospedale S. Giovanni di Dio, Frattamaggiore, NA (Italy). Servizio di Radiologia; De Rosa, A.; Nunziata, A. [Ospedale Loreto Mare, Neaples (Italy). Servizio di Radiologia; Rossi, E.; Brunese, L. [Universita' degli Studi Federico II, Neaples (Italy). Ist. di Scienze Radiologiche; Tuccillo, M. [Azienda Ospedaliera di Rilievo Nazionale A. Cardarelli, Neaples (Italy). Servizio di Radiologia; Grassi, R. [Seconda Universita' degli Studi, Neaples (Italy). Ist. di Radiologia

    2000-03-01

    With the aim of demonstrating the usefulness of computerised tomography (CT) findings in the planning of brain neurosurgery in gunshot victims, for prompt and successful treatment, 30 patients with brain gunshot wounds were examined with CT over 5 years. The mortality rate of firearm wounds of the skull base was 34% higher than that of the hemisphere; this is due to carotid hemorrhage and midbrain damage. Such traumas require emergency radiological diagnosis and neurosurgical treatment because of their severity and early irreversible complications. Complex operations and skilled surgeons may prevent disabling postoperative sequels. CT findings are indispensable and must be correctly interpreted. The radiologist and the neurosurgeon must collaborate closely and both must consider several diagnostic factors affecting surgical planning. [Italian] Scopo dello studio e' stato quello di dimostrare l'utilita' della semeiologia della tomografia computerizzata in relazione con la pianificazione dell'intervento neochirurgico, al fine di attuare con tempestivita' interventi chirurgici soddisfacenti e meno lesivi. Lo studio comprende 30 casi di lesioni cranio-encefaliche da arma da fuoco esaminate con tomografia computerizzata nel periodo di 5 anni. Materiali e metodi utilizzati sono analiticamente descritti. L'esperienza dimostra che nelle lesioni da arma da fuoco del basicranio si nota una mortalita' del 34% superiore rispetto a quelle piu' craniali come quelle emisferiche in relazione a emorragie carotidee e lesioni tronco-mesencefaliche. Tali traumi esigono diagnosi radiologica e terapia neurochirurgica d'urgenza per la gravita' e le precoci complicanze irreversibili. Cio' richiede interventi complessi e manualita' esperte e rapide al fine di evitare sequele postoperatorie invalidanti. La corretta e indispensabile interpretazione dei segni radiologici della tomografia computerizzata deve avvenire in stretta

  5. Stability management of high speed axial flow compressor stage through axial extensions of bend skewed casing treatment

    Directory of Open Access Journals (Sweden)

    DilipkumarBhanudasji Alone

    2016-09-01

    Full Text Available This paper presents the experimental results to understand the performance of moderately loaded high speed single stage transonic axial flow compressor subjected to various configurations of axial extensions of bend skewed casing treatment with moderate porosity. The bend skewed casing treatment of 33% porosity was coupled with rectangular plenum chamber of depth equal to the slots depth. The five axial extensions of 20%, 40%, 60%, 80% and 100% were used for the experimental evaluations of compressor performance. The main objective was to identify the optimum extension of the casing treatment with reference to rotor leading edge which results in maximum stall margin improvements with minimum loss in the stage efficiency. At each axial extension the compressor performance is distinctive. The improvement in the stall margin was very significant at some axial extensions with 4%–5% penalty in the stage efficiency. The compressors stage shows recovery in terms of efficiency at lower axial extensions of 20% and 40% with increase in the peak stage efficiency. Measurements of flow parameters showed the typical behaviors at near stall flow conditions. Hot wire sensor was placed at the rotor upstream in the tip region to capture the oscillations in the inlet axial and tangential velocities at stall conditions. In the absence of casing treatment the compressor exhibit abrupt stall with very high oscillations in the inlet axial and tangential velocity of the flow. The extents of oscillations reduce with bend skewed casing treatment. Few measurements were also performed in the plenum chamber and salient results are presented in this paper.

  6. On renormalization of axial anomaly

    International Nuclear Information System (INIS)

    Efremov, A.V.; Teryaev, O.V.

    1989-01-01

    It is shown that multiplicative renormalization of the axial singlet current results in renormalization of the axial anomaly in all orders of perturbation theory. It is a necessary condition for the Adler - Bardeen theorem being valid. 10 refs.; 2 figs

  7. High temperature co-axial winding transformers

    Science.gov (United States)

    Divan, Deepakraj M.; Novotny, Donald W.

    1993-01-01

    The analysis and design of co-axial winding transformers is presented. The design equations are derived and the different design approaches are discussed. One of the most important features of co-axial winding transformers is the fact that the leakage inductance is well controlled and can be made low. This is not the case in conventional winding transformers. In addition, the power density of co-axial winding transformers is higher than conventional ones. Hence, using co-axial winding transformers in a certain converter topology improves the power density of the converter. The design methodology used in meeting the proposed specifications of the co-axial winding transformer specifications are presented and discussed. The final transformer design was constructed in the lab. Co-axial winding transformers proved to be a good choice for high power density and high frequency applications. They have a more predictable performance compared with conventional transformers. In addition, the leakage inductance of the transformer can be controlled easily to suit a specific application. For space applications, one major concern is the extraction of heat from power apparatus to prevent excessive heating and hence damaging of these units. Because of the vacuum environment, the only way to extract heat is by using a cold plate. One advantage of co-axial winding transformers is that the surface area available to extract heat from is very large compared to conventional transformers. This stems from the unique structure of the co-axial transformer where the whole core surface area is exposed and can be utilized for cooling effectively. This is a crucial issue here since most of the losses are core losses.

  8. The Design Method of Axial Flow Runners Focusing on Axial Flow Velocity Uniformization and Its Application to an Ultra-Small Axial Flow Hydraulic Turbine

    Directory of Open Access Journals (Sweden)

    Yasuyuki Nishi

    2016-01-01

    Full Text Available We proposed a portable and ultra-small axial flow hydraulic turbine that can generate electric power comparatively easily using the low head of open channels such as existing pipe conduits or small rivers. In addition, we proposed a simple design method for axial flow runners in combination with the conventional one-dimensional design method and the design method of axial flow velocity uniformization, with the support of three-dimensional flow analysis. Applying our design method to the runner of an ultra-small axial flow hydraulic turbine, the performance and internal flow of the designed runner were investigated using CFD analysis and experiment (performance test and PIV measurement. As a result, the runners designed with our design method were significantly improved in turbine efficiency compared to the original runner. Specifically, in the experiment, a new design of the runner achieved a turbine efficiency of 0.768. This reason was that the axial component of absolute velocity of the new design of the runner was relatively uniform at the runner outlet in comparison with that of the original runner, and as a result, the negative rotational flow was improved. Thus, the validity of our design method has been verified.

  9. Origin of axial current in scyllac

    International Nuclear Information System (INIS)

    Sugisaki, K.

    1975-12-01

    The origin of the axial current observed in Scyllac (a high beta stellarator experiment) is discussed. A shaped coil and/or helical winding produce rotational transform which links magnetic lines of force to the plasma column and the axial current is induced electromagnetically. This phenomenon is inherent in a pulsed high-beta stellarator. The rotational transform produced by the induced axial current is much smaller than that associated with the l = 1, 0 equilibrium fields. The effect of the axial current on the equilibrium and stability of the plasma column is thus small. It is also shown that the magnetic field shear near a plasma surface is very strong

  10. Descrição anatômica das estruturas osteoarticulares do esqueleto axial do tatu-galinha (Dasypus novemcinctus Linnaeus, 1758) por meio da radiografia e tomografia computadorizada

    OpenAIRE

    Alves, Lidiane da Silva [UNESP

    2016-01-01

    O tatu-galinha é um dos animais mais populosos da ordem Xenarthra com distribuição do sul dos Estados Unidos até a América do Sul. São animais frequentemente caçados e, em muitos casos, são vítimas de atropelamentos rodoviários. Existem diversos estudos descritivos sobre a fisiologia, a genética e o comportamento, porém a anatomia óssea e articular destes animais ainda é restrita. Este estudo tem por objetivo, descrever a anatomia das estruturas osteoarticulares do esqueleto axial em 20 tatus...

  11. New molecular targets for PET and SPECT imaging in neurodegenerative diseases Novos alvos moleculares para tomografia por emissão de pósitrons (PET e tomografia computadorizada por emissão de fóton único (SPECT em doenças neurodegenerativas

    Directory of Open Access Journals (Sweden)

    Marcel Benadiba

    2012-10-01

    Full Text Available The pathophysiology of neurodegenerative diseases (ND such as Alzheimer's disease (AD and Parkinson's disease (PD has not yet been completely elucidated. However, in the past few years, there have been great knowledge advances about intra-and extracellular proteins that may display impaired function or expression in AD, PD and other ND, such as amyloid beta (Aβ, α-synuclein, tau protein and neuroinflammatory markers. Recent developments in the imaging techniques of positron emission tomography (PET and single photon emission computed tomography (SPECT now allow the non-invasive tracking of such molecular targets of known relevance to ND in vivo. This article summarizes recent findings of PET and SPECT studies using these novel methods, and discusses their potential role in the field of drug development for ND as well as future clinical applications in regard to differential diagnosis of ND and monitoring of disease progression.A fisiopatologia das doenças neurodegenerativas (DN, tais como a doença de Alzheimer (DA e a doença de Parkinson (DP, ainda não é completamente compreendida. No entanto, nos últimos anos, houve grandes avanços em termos do conhecimento sobre proteínas intra e extracelulares, tais como beta-amiloide (Aβ, α-sinucleína, proteína tau e marcadores neuroinflamatórios, que podem ter sua função ou expressão prejudicada na DA, DP ou em outras DN. Progressos recentes nas técnicas de tomografia por emissão de pósitrons (PET e tomografia computadorizada por emissão de fóton único (SPECT permitem hoje em dia a identificação não invasiva de tais alvos moleculares in vivo. Este artigo resume descobertas recentes de estudos de PET e SPECT cerebral usando esses alvos moleculares inovadores e discute o papel potencial dessas técnicas no campo do desenvolvimento de novos medicamentos para as DN, bem como futuras aplicações clínicas em relação ao diagnóstico diferencial e monitoramento da progressão dessas

  12. Estudo da síndrome de tração macular vítreo-retiniana idiopática por meio da tomografia de coerência óptica: relato de casos A study of idiophatic vitreomacular traction syndrome with optical coherence tomography images: cases report

    Directory of Open Access Journals (Sweden)

    Hélio Paulo Primiano Júnior

    2007-02-01

    Full Text Available OBJETIVOS: Avaliar alterações estruturais observadas na síndrome de tração macular vítreo-retiniana idiopática (STMI pela tomografia de coerência óptica (OCT, antes e depois da vitrectomia; identificar situações em que a tomografia de coerência óptica fornece informações adicionais da morfologia e patogênese desta doença. MÉTODOS: Imagens tomográficas (OCT Stratus comparativas da estrutura vítreo-retiniana foram realizadas em quatro pacientes, em estágios variados da síndrome de tração macular vítreo-retiniana idiopática. RESULTADOS: A tomografia de coerência óptica Stratus apresenta imagens vítreo-retinianas que auxiliam na conduta e tratamento da síndrome de tração macular vítreo-retiniana idiopatica. CONCLUSÃO: O exame da tomografia de coerência óptica permite boa visualização da arquitetura morfológica do vítreo e da retina na síndrome de tração macular vítreo-retiniana idiopática. Este exame nos auxilia na compreensão da patogênese, no planejamento do tratamento, clínico ou cirúrgico, e na avaliação pós-operatória das alterações estruturais retinianas.PURPOSE: To evaluate the features of idiophatic vitreomacular traction syndrome (VMT with ocular coherence tomography (OCT - Stratus, before and after vitrectomy; to identify situations where ocular coherence tomography provides additional information on disease morphology and pathogenesis. METHODS: Comparative retinal ocular coherence tomography imaging was performed in four patients with different stages of vitreomacular traction syndrome. RESULTS: Standard-resolution ocular coherence tomography Stratus provides vitreous-retinal images that help the management and treatment of vitreomacular traction syndrome. CONCLUSIONS: Standard-resolution ocular coherence tomography allows good visualization of the architectural morphology of the vitreous and retina in vitreomacular traction syndrome. It helps understanding its pathogenesis, planning

  13. Estimativa dos valores de MSAD em procedimentos de tomografia computadorizada utilizando filmes radiocrômicos

    Directory of Open Access Journals (Sweden)

    Bruno Beraldo Oliveira

    2013-04-01

    Full Text Available OBJETIVO: Verificar a viabilidade de filmes radiocrômicos como um dosímetro alternativo para estimativa da dose média em cortes múltiplos a partir dos perfis de kerma. MATERIAIS E MÉTODOS: Os filmes foram distribuídos em cilindros posicionados no centro e nas regiões periféricas de um objeto simulador padrão de abdome utilizado para dosimetria em tomografia computadorizada. RESULTADOS: Os valores de dose média em cortes múltiplos calculados foram 13,6 ± 0,7, 13,5 ± 0,7 e 18,7 ± 1,0 mGy para os valores de passo (pitch de 0,75, 1,00 e 1,50, respectivamente. CONCLUSÃO: Apesar de os resultados mostrarem valores menores que o nível de referência de radiodiagnóstico de 25 mGy estabelecido pela legislação brasileira para exames de abdome, eles sugerem que há espaço para otimização dos procedimentos e uma revisão do valor para o nível de referência de radiodiagnóstico brasileiro.

  14. Vector and axial constants of the baryon decuplet

    International Nuclear Information System (INIS)

    Belyaev, V.M.; Blok, B.Y.; Kogan, Y.I.

    1985-01-01

    On the basis of the QCD sum rules for the polarization operator in external axial and vector fields we determine the vector and axial transition constants in the 3/2 + baryon decuplet. We show that the renormalization of the axial constant is due to the interaction of the external axial field with the quark condensate

  15. Axial gap rotating electrical machine

    Science.gov (United States)

    None

    2016-02-23

    Direct drive rotating electrical machines with axial air gaps are disclosed. In these machines, a rotor ring and stator ring define an axial air gap between them. Sets of gap-maintaining rolling supports bear between the rotor ring and the stator ring at their peripheries to maintain the axial air gap. Also disclosed are wind turbines using these generators, and structures and methods for mounting direct drive rotating electrical generators to the hubs of wind turbines. In particular, the rotor ring of the generator may be carried directly by the hub of a wind turbine to rotate relative to a shaft without being mounted directly to the shaft.

  16. Study of axial magnetic effect

    Energy Technology Data Exchange (ETDEWEB)

    Braguta, Victor [IHEP, Protvino, Moscow region, 142284 Russia ITEP, B. Cheremushkinskaya street 25, Moscow, 117218 (Russian Federation); School of Biomedicine, Far Eastern Federal University, Ajax 10 Building 25, Russian island, Vladivostok, 690922 (Russian Federation); Chernodub, M. N. [CNRS, Laboratoire de Mathématiques et Physique Théorique, Université François-Rabelais Tours, Fédération Denis Poisson, Parc de Grandmont, 37200 Tours, France Department of Physics and Astronomy, University of Gent, Krijgslaan 281, S9, B-9000 Gent (Belgium); School of Biomedicine, Far Eastern Federal University, Ajax 10 Building 25, Russian island, Vladivostok, 690922 (Russian Federation); Goy, V. A. [School of Natural Sciences, Far Eastern Federal University, Sukhanova street 8, Vladivostok, 690950 (Russian Federation); Landsteiner, K. [Instituto de Física Teórica UAM/CSIC, C/ Nicolás Cabrera 13-15, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Molochkov, A. V. [School of Biomedicine, Far Eastern Federal University, Ajax 10 Building 25, Russian island, Vladivostok, 690922 (Russian Federation); Ulybyshev, M. [ITEP, B. Cheremushkinskaya street 25, Moscow, 117218 Russia Institute for Theoretical Problems of Microphysics, Moscow State University, Moscow, 119899 (Russian Federation)

    2016-01-22

    The Axial Magnetic Effect manifests itself as an equilibrium energy flow of massless fermions induced by the axial (chiral) magnetic field. Here we study the Axial Magnetic Effect in the quenched SU(2) lattice gauge theory with massless overlap fermions at finite temperature. We numerically observe that in the low-temperature hadron phase the effect is absent due to the quark confinement. In the high-temperature deconfinement phase the energy flow is an increasing function of the temperature which reaches the predicted asymptotic T{sup 2} behavior at high temperatures. We find, however, that energy flow is about one order of magnitude lower compared to a theoretical prediction.

  17. Electric machines with axial magnetic flux

    Science.gov (United States)

    Nuca, I.; Ambros, T.; Burduniuc, M.; Deaconu, S. I.; Turcanu, A.

    2018-01-01

    The paper contains information on the performance of axial machines compared to cylindrical ones. At the same time, various constructive schemes of synchronous electromechanical converters with permanent magnets and asynchronous with short-circuited rotor are presented. In the developed constructions, the aim is to maximize the usage of the material of the stator windings. The design elements of the axial machine magnetic system are presented. The FEMM application depicted the array of the magnetic field of an axial machine.

  18. Intrinsic carpal ligaments on MR and multidetector CT arthrography: comparison of axial and axial oblique planes

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ryan K.L.; Griffith, James F.; Ng, Alex W.H.; Law, Eric K.C. [The Chinese University of Hong Kong, Department of Imaging and Interventional Radiology, Prince Of Wales Hospital, Hong Kong (China); Tse, W.L.; Wong, Clara W.Y.; Ho, P.C. [The Chinese University of Hong Kong, Department of Orthopedics and Traumatology, Prince Of Wales Hospital, Hong Kong (China)

    2017-03-15

    To compare axial and oblique axial planes on MR arthrography (MRA) and multidetector CT arthrography (CTA) to evaluate dorsal and volar parts of scapholunate (SLIL) and lunotriquetral interosseous (LTIL) ligaments. Nine cadaveric wrists of five male subjects were studied. The visibility of dorsal and volar parts of the SLIL and LTIL was graded semi-quantitatively (good, intermediate, poor) on MRA and CTA. The presence of a ligament tear was determined on arthrosocopy and sensitivity, specificity and accuracy of tear detection were calculated. Oblique axial imaging was particularly useful for delineating dorsal and volar parts of the LTIL on MRA with overall 'good' visibility increased from 11 % to 78 %. The accuracy of MRA and CTA in revealing SLIL and LTIL tear was higher using the oblique axial plane. The overall accuracy for detecting SLIL tear on CTA improved from 94 % to 100 % and from 89 % to 94 % on MRA; the overall accuracy of detecting LTIL tear on CTA improved from 89 % to 100 % and from 72 % to 89 % on MRA Oblique axial imaging during CT and MR arthrography improves detection of tears in the dorsal and volar parts of both SLIL and LTIL. (orig.)

  19. Radial and axial compression of pure electron

    International Nuclear Information System (INIS)

    Park, Y.; Soga, Y.; Mihara, Y.; Takeda, M.; Kamada, K.

    2013-01-01

    Experimental studies are carried out on compression of the density distribution of a pure electron plasma confined in a Malmberg-Penning Trap in Kanazawa University. More than six times increase of the on-axis density is observed under application of an external rotating electric field that couples to low-order Trivelpiece-Gould modes. Axial compression of the density distribution with the axial length of a factor of two is achieved by controlling the confining potential at both ends of the plasma. Substantial increase of the axial kinetic energy is observed during the axial compression. (author)

  20. View of the Axial Field Spectrometer

    CERN Multimedia

    1980-01-01

    The Axial Field Spectrometer, with the vertical uranium/scintillator calorimeter and the central drift chamber retracted for service. One coil of the Open Axial Field Magnet is just visible to the right.

  1. Tomografia computadorizada aplicada a estudos de um Planossolo

    Directory of Open Access Journals (Sweden)

    Pedrotti Alceu

    2003-01-01

    Full Text Available Na busca de técnicas mais apuradas para a determinação e avaliação de parâmetros físicos do solo com aplicabilidade em várzeas, vem se destacando a tomografia computadorizada, por medir a densidade e a umidade com boa sensibilidade e alta resolução espacial. O presente trabalho teve como objetivo descrever aspectos e procedimentos da calibração de um minitomógrafo de raios-X e gama para estudo da densidade e umidade de um Planossolo no Rio Grande do Sul, bem como estabelecer parâmetros estatísticos para sua adequada utilização. A calibração do minitomógrafo foi obtida pela regressão linear entre as unidades tomográficas (UT, apresentadas pelo programa de reconstrução de imagem, e os coeficientes de atenuação linear (µl, cm-1, medidos por transmissão direta de raios gama, em amostras dos horizontes A e B do Planossolo, água destilada, benzina e alumínio. Para as medidas de transmissão direta de radiação utilizaram-se recipientes com água destilada, benzina, solo e Al, obtendo-se as seguintes fórmulas para o cálculo da densidade do solo no horizonte A: Ds = [(UT/986,16-(0,200xteta]/0,267; e no horizonte B: Ds = [(UT/986,16-(0,200xteta]/0,297, em que UT é o valor médio de UT em cada linha e teta é a umidade volumétrica da amostra de solo, em m³ m-3. Com as configurações obtidas, verificou-se variabilidade média de 2,74% e 0,73%, respectivamente, em termos de homogeneidade e repetibilidade. Os erros atribuídos ao equipamento são de 0,051 e 0,046 Mg m-3, respectivamente, nos horizontes A e B, revelando precisão e adaptabilidade no emprego da técnica em estudos do Planossolo.

  2. Displasia de Mondini asociada a meningitis bacteriana recurrente, correlación clínico-imagenológica

    Directory of Open Access Journals (Sweden)

    Julianis Loraine Quintero Noa

    Full Text Available Se describe la displasia de Mondini asociada a pérdida auditiva y meningitis bacteriana recurrente. La malformación de Mondini representa el 30 % de las anomalías congénitas del oído interno, puede ser unilateral o bilateral, y su principal característica consiste en el desarrollo coclear incompleto, causante de grados variables de hipoacusia neurosensorial. Se considera que la ocurrencia de esta malformación se produce por disrupción del desarrollo embrionario durante la séptima semana de gestación, en la cual se detiene el desarrollo coclear. Se presenta el caso de una niña de 12 años, atendida en los Servicios de Pediatría y Otorrinolaringología del Hospital Pediátrico Universitario "William Soler", por presentar 3 infecciones meningoencefálicas, en las cuales se aisló Streptococcus pneumoniae serotipo 19F, y se constató hipoacusia neurosensorial severa en el oído izquierdo. La tomografía axial computarizada de alta resolución del oído (cortes axiales y coronales, evidenció la malformación coclear y vestibular, con presencia de tejido en el oído medio que se comunicaba directamente con el oído interno del lado izquierdo a nivel de la ventana oval. Se destaca la importancia de la sospecha clínica de displasia de Mondini, y el impacto científico de la tomografía computarizada del hueso temporal, para el diagnóstico precoz de fístula congénita en el oído interno asociada a meningitis bacteriana recurrente.

  3. Temporal and Spatial Variability in the Geochemistry of Axial and CoAxial Segment Lavas and their Mantle Sources

    Science.gov (United States)

    Smith, M. C.; Perfit, M. R.; Davis, C.; Kamenov, G. D.

    2011-12-01

    Three spatially related volcanic eruptions along the CoAxial Segment of the Juan de Fuca Ridge (JdFR) have documented emplacements between 1981 and 1993. Two of the historic flows outcrop at the "Flow Site" and were emplaced within less than 12 years and 500 m from one another. The third was emplaced at the "Floc Site" to the south in the 1980s. Previous studies have documented that CoAxial lavas are among the most incompatible element and isotopically depleted lavas along the entire JdFR, whereas the Axial Seamount segment immediately south of CoAxial has erupted the most chemically enriched lavas south of the Endeavor Segment. Geochemical studies have shown little temporal change in the chemistry of recent Axial Seamount eruptives, whereas CoAxial lavas exhibit distinct chemical differences over short time periods. Significant chemical differences observed among depleted CoAxial lavas emplaced close to one another in space and time are in marked contrast to the relatively constant chemical characteristics of enriched lavas erupted at the magmatically more robust Axial segment only 10's of kilometers to the south and west. New trace element and isotopic (Sr, Nd, Pb) geochemical analyses of historic and older CoAxial lavas have resulted in better documentation of interflow and intraflow chemical variation providing an improved understanding of spatial/temporal chemical variability in lavas, and further insight into JdFR magmatic processes. Modeling of major and trace element abundances suggest that the observed intraflow chemical variation within CoAxial lavas is largely due to shallow-level fractional crystallization but that a single fractional crystallization model cannot account for all interflow chemical variation. In fact, elemental and isotopic data require different parental magmas for each of the three recent CoAxial Segment lava flows suggesting very short-term differences or changes in the chemical character of the mantle source region. In particular

  4. Retinal thickness assessed by optical coherence tomography (OCT in pseudophakic macular edema Espessura retiniana medida pela tomografia de coerência óptica (OCT no edema macular do pseudofácico

    Directory of Open Access Journals (Sweden)

    Maria Teresa Brizzi Chizzoti Bonanomi

    2006-08-01

    Full Text Available PURPOSE: To evaluate the usefulness of the optical coherence tomography (OCT retinal map in angiographic pseudophakic macular edema (ACME. METHODS: This is a prospective analysis of a group of 36 pseudophakic eyes at the fifth postoperative week, submitted to optical coherence tomography 2 macular map and fluorescein angiography on the same day and, a control group of twenty-two 20/20 vision eyes with a minimum 6-month postoperative period, submitted to optical coherence tomography 2 macular map only. Exclusion criteria were diabetes, any macular pathology and unreadable optical coherence tomography or angiogram. The angiograms were divided into three groups according to the edema intensity: Group I: level 0 (absence of angiographic pseudophakic macular edema; group II: levels 1 and 2 (incomplete and complete perifoveal angiographic pseudophakic macular edema respectively and group III: levels 3 and 4 (up to one disc diameter and greater than one disc diameter angiographic pseudophakic macular edema area respectively. The nine zones of the optical coherence tomography macular map were compared between the control and the three subgroups of the study group and, between group I and groups II and III. RESULTS: Among the 36 eyes, 23 (64% were classified as group I, 10 (28% as group II and three (8% as group III. The mean thickness of the fovea zone was 185±15 µm for the control group, 189±24 µm for group I, 213±33 µm for group II and 455±38 µm for group III. Significant differences: between group III and the control or group I for all zones (pOBJETIVO: Medir a espessura retiniana pela tomografia de coerência óptica (OCT no edema macular angiográfico do pseudofácico (ACME. MÉTODOS: Trabalho prospectivo composto de um grupo de estudo com 36 olhos pseudofácicos, entre a 4ª e a 6ª semana de pós-operatório, submetidos ao mapa macular com a tomografia de coerência óptica 2 e à angiofluoresceinografia no mesmo dia e, um grupo controle

  5. Axial vector mass spectrum and mixing angles

    International Nuclear Information System (INIS)

    Caffarelli, R.V.; Kang, K.

    1976-01-01

    Spectral sum rules of the axial-vector current and axial-vector current-pseudoscalar field are used to study the axial-vector mass spectrum and mixing angles, as well as the decay constants and mixing angles of the pseudoscalar mesons. In general, the result is quite persuasive for the existence of the Jsup(PC) = 1 ++ multiplet in which one has a canonical D-E mixing. (Auth.)

  6. Axial flow heat exchanger devices and methods for heat transfer using axial flow devices

    Science.gov (United States)

    Koplow, Jeffrey P.

    2016-02-16

    Systems and methods described herein are directed to rotary heat exchangers configured to transfer heat to a heat transfer medium flowing in substantially axial direction within the heat exchangers. Exemplary heat exchangers include a heat conducting structure which is configured to be in thermal contact with a thermal load or a thermal sink, and a heat transfer structure rotatably coupled to the heat conducting structure to form a gap region between the heat conducting structure and the heat transfer structure, the heat transfer structure being configured to rotate during operation of the device. In example devices heat may be transferred across the gap region from a heated axial flow of the heat transfer medium to a cool stationary heat conducting structure, or from a heated stationary conducting structure to a cool axial flow of the heat transfer medium.

  7. Inverse axial mounting stiffness design for lithographic projection lenses.

    Science.gov (United States)

    Wen-quan, Yuan; Hong-bo, Shang; Wei, Zhang

    2014-09-01

    In order to balance axial mounting stiffness of lithographic projection lenses and the image quality under dynamic working conditions, an easy inverse axial mounting stiffness design method is developed in this article. Imaging quality deterioration at the wafer under different axial vibration levels is analyzed. The desired image quality can be determined according to practical requirements, and axial vibrational tolerance of each lens is solved with the damped least-squares method. Based on adaptive interval adjustment, a binary search algorithm, and the finite element method, the axial mounting stiffness of each lens can be traveled in a large interval, and converges to a moderate numerical solution which makes the axial vibrational amplitude of the lens converge to its axial vibrational tolerance. Model simulation is carried out to validate the effectiveness of the method.

  8. Energy Dissipation in Sandwich Structures During Axial Compression

    DEFF Research Database (Denmark)

    Urban, Jesper

    2002-01-01

    The purpose of this paper is to investigate the energy dissipation in sandwich structures during axial crushing. Axial crushing tests on six sandwich elements are described. The sandwich elements consist of a polyurethane core and E-glass/Polyester skin. The elements compare to full-scale structu......The purpose of this paper is to investigate the energy dissipation in sandwich structures during axial crushing. Axial crushing tests on six sandwich elements are described. The sandwich elements consist of a polyurethane core and E-glass/Polyester skin. The elements compare to full...

  9. Improved axial position detection in optical tweezers measurements

    DEFF Research Database (Denmark)

    Dreyer, Jakob Kisbye; Berg-Sørensen, Kirstine; Oddershede, Lene

    2004-01-01

    We investigate the axial position detection of a trapped microsphere in an optical trap by using a quadrant photodiode. By replacing the photodiode with a CCD camera, we obtain detailed information on the light scattered by the microsphere. The correlation of the interference pattern with the axial...... position displays complex behavior with regions of positive and negative interference. By analyzing the scattered light intensity as a function of the axial position of the trapped sphere, we propose a simple method to increase the sensitivity and control the linear range of axial position detection....

  10. Comparison of femoropopliteal artery stents under axial and radial compression, axial tension, bending, and torsion deformations.

    Science.gov (United States)

    Maleckis, Kaspars; Deegan, Paul; Poulson, William; Sievers, Cole; Desyatova, Anastasia; MacTaggart, Jason; Kamenskiy, Alexey

    2017-11-01

    High failure rates of Peripheral Arterial Disease (PAD) stenting appear to be associated with the inability of certain stent designs to accommodate severe biomechanical environment of the femoropopliteal artery (FPA) that bends, twists, and axially compresses during limb flexion. Twelve Nitinol stents (Absolute Pro, Supera, Lifestent, Innova, Zilver, Smart Control, Smart Flex, EverFlex, Viabahn, Tigris, Misago, and Complete SE) were quasi-statically tested under bench-top axial and radial compression, axial tension, bending, and torsional deformations. Stents were compared in terms of force-strain behavior, stiffness, and geometrical shape under each deformation mode. Tigris was the least stiff stent under axial compression (6.6N/m axial stiffness) and bending (0.1N/m) deformations, while Smart Control was the stiffest (575.3N/m and 105.4N/m, respectively). Under radial compression Complete SE was the stiffest (892.8N/m), while Smart Control had the lowest radial stiffness (211.0N/m). Viabahn and Supera had the lowest and highest torsional stiffness (2.2μNm/° and 959.2μNm/°), respectively. None of the 12 PAD stents demonstrated superior characteristics under all deformation modes and many experienced global buckling and diameter pinching. Though it is yet to be determined which of these deformation modes might have greater clinical impact, results of the current analysis may help guide development of new stents with improved mechanical characteristics. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Axial anomaly at finite temperature and finite density

    International Nuclear Information System (INIS)

    Qian Zhixin; Su Rukeng; Yu, P.K.N.

    1994-01-01

    The U(1) axial anomaly in a hot fermion medium is investigated by using the real time Green's function method. After calculating the lowest order triangle diagrams, we find that finite temperature as well as finite fermion density does not affect the axial anomaly. The higher order corrections for the axial anomaly are discussed. (orig.)

  12. Avaliação por imagem da área de gordura visceral e suas correlações com alterações metabólicas Evaluación por imagen del área de grasa visceral y sus correlaciones con alteraciones metabólicas Imaging assessment of visceral adipose tissue area and its correlations with metabolic alterations

    Directory of Open Access Journals (Sweden)

    Anna Karla Carneiro Roriz

    2010-12-01

    Full Text Available FUNDAMENTO: A obesidade androgênica está associada a um risco maior de distúrbios metabólicos, favorecendo assim a ocorrência de doenças cardiovasculares e outras morbidades. OBJETIVO: Verificar a influência da área de tecido adiposo visceral (ATAV, medida pela tomografia computadorizada, sobre alterações metabólicas em adultos e idosos. MÉTODOS: Tomografias computadorizadas e valores de lipoproteínas: o colesterol total e frações, os triglicérides, a glicemia e o ácido úrico foram obtidos de 194 indivíduos estratificados por sexo, grupo etário e massa corporal, e analisados utilizando os testes de correlação e de média. RESULTADOS: Os idosos apresentaram maiores valores da ATAV, glicemia, ácido úrico e colesterol total. As maiores correlações foram encontradas entre a ATAV, os triglicérides e o VLDL-c (r > 0,5; p FUNDAMENTO: La obesidad androgénica está asociada a un riesgo mayor de disturbios metabólicos, favoreciendo así la ocurrencia de enfermedades cardiovasculares y otras morbilidades. OBJETIVOS: Verificar la influencia del área de tejido adiposo visceral (ATAV, medida por la tomografía computarizada, sobre alteraciones metabólicas en adultos y adultos mayores. MÉTODOS: Tomografías computarizadas y valores de lipoproteínas: el colesterol total y fracciones, los triglicéridos, la glucemia y el ácido úrico se obtuvieron de 194 individuos estratificados por sexo, grupo de edad y masa corporal, y se analizaron utilizando las pruebas de correlación y de promedio. RESULTADOS: Los adultos mayores presentaron mayores valores de la ATAV, glucemia, ácido úrico y colesterol total. Las mayores correlaciones se encontraron entre la ATAV, los triglicéridos y el VLDL-c (r > 0,5; p BACKGROUND: Androgenic obesity is associated with a higher risk of metabolic disorders, thus favoring the occurrence of cardiovascular diseases and other morbidities. OBJECTIVE: To verify the influence of the visceral adipose tissue

  13. Proposta para padronização do relatório de tomografia computadorizada nos aneurismas da aorta abdominal A proposal for standardizing computed tomography reports on abdominal aortic aneurysms

    Directory of Open Access Journals (Sweden)

    Fabiola Goda Torlai

    2006-08-01

    Full Text Available OBJETIVO: Propor um modelo de padronização de relatório para aneurisma da aorta abdominal na tomografia computadorizada. MATERIAIS E MÉTODOS: Foram realizadas, no período de abril a outubro de 2004, entrevistas com integrantes da Disciplina de Cirurgia Vascular da nossa instituição, para elaboração de um modelo de padronização de relatório de tomografia computadorizada para o estudo do aneurisma da aorta abdominal. A partir deste modelo foi elaborado um questionário, enviado a nove outros cirurgiões, todos com experiência em cirurgia da aorta abdominal. O índice de resposta aos questionários foi de 55,5% (5/9. RESULTADOS: Os parâmetros de interesse citados mais freqüentemente para a avaliação dos aneurismas de aorta abdominal foram: diâmetro máximo do colo proximal, extensão do colo proximal até a artéria renal mais baixa, forma do colo proximal, diâmetro máximo do aneurisma e diâmetro das artérias ilíacas comuns. Estes dados permitiram elaborar uma proposta de modelo para padronização de relatório na tomografia computadorizada. CONCLUSÃO: Um modelo para a análise tomográfica padronizada do aneurisma de aorta abdominal permite atender às necessidades dos cirurgiões vasculares para acompanhar a evolução e planejar o tratamento destes pacientes.OBJECTIVE: To propose a model to standardize computed tomography reports on abdominal aortic aneurysms. MATERIALS AND METHODS: Interviews were carried out with members of Vascular Surgery Division of our institution, in the period between April and October 2004, aiming at developing a standardized model of computed tomography reports on abdominal aortic aneurysms. Based on this model, a questionnaire was elaborated and sent to other nine surgeons, all of them experienced in the field of abdominal aortic surgery. The questionnaires response rate was 55.5% (5/9. RESULTS: The most frequently mentioned parameters of interest for evaluation of abdominal aortic aneurysms

  14. Review of Axial Burnup Distribution Considerations for Burnup Credit Calculations

    International Nuclear Information System (INIS)

    Wagner, J.C.; DeHart, M.D.

    2000-01-01

    This report attempts to summarize and consolidate the existing knowledge on axial burnup distribution issues that are important to burnup credit criticality safety calculations. Recently released Nuclear Regulatory Commission (NRC) staff guidance permits limited burnup credit, and thus, has prompted resolution of the axial burnup distribution issue. The reactivity difference between the neutron multiplication factor (keff) calculated with explicit representation of the axial burnup distribution and keff calculated assuming a uniform axial burnup is referred to as the ''end effect.'' This end effect is shown to be dependent on many factors, including the axial-burnup profile, total accumulated burnup, cooling time, initial enrichment, assembly design, and the isotopics considered (i.e., actinide-only or actinides plus fission products). Axial modeling studies, efforts related to the development of axial-profile databases, and the determination of bounding axial profiles are also discussed. Finally, areas that could benefit from further efforts are identified

  15. CT diagnosis of subphrenic abscess after splenectomy for trauma; Ruolo della tomografia computerizzata nella valutazione degli ascessi subfrenici dopo splenectomia post-traumatica

    Energy Technology Data Exchange (ETDEWEB)

    Salzano, A. [Ospedale Loreto-Mare, Neaples (IT). Serv. di Radiologia] [and others

    1999-09-01

    The paper studies subphrenic inflammatory abscesses and splenic fluid collections after splenectomy for trauma. These complications may appear early or late postoperatively; they are easily demonstrated with computerized tomography, which permits accurate spatial assessment of the lesions and appropriate treatment with percutaneous drainage. It has been also investigates the diagnostic accuracy of the CT in subphrenic inflammatory conditions after emergency splenectomy for traumatic spleen rupture and found that CT is a precious tool for rapid and easy diagnosis and follow-up of subphrenic abscesses treated with percutaneous drainage. [Italian] Scopo del lavoro e' di valutare il ruolo della tomografia computerizzata nelle flogrosi subfreniche secondarie a splenectomia d'urgenza per rottura traumatica della milza, documentando come tale metodica risulti accurata nel diagnosticare e monitorare in modo semplice e rapido l'evoluzione e il controllo degli ascessi subfrenici trattati con drenaggio percutaneo.

  16. Research on a novel axial-flux magnetic-field-modulated brushless double-rotor machine with low axial force and high efficiency

    Directory of Open Access Journals (Sweden)

    Chengde Tong

    2017-05-01

    Full Text Available The axial-flux magnetic-field-modulated brushless double-rotor machine (MFM-BDRM is a possible alternative as a power-split device for hybrid electric vehicles (HEVs. However, the existence of large axial force may lead to assembly problems and rich inner air-gap harmonics could result in high PM loss and low efficiency. This paper proposes a novel axial-flux MFM-BDRM with improved PM rotor structure. 2-D analytical method to predict the magnetic-field distribution of the proposed MFM-BDRM is developed and the design procedure of the proposed machine is illustrated. The impact of key geometrical parameters on axial force and torque is investigated. To evaluate the advantage of the proposed machine, a comparison is made with a conventional one with respect to electromagnetic performances. Results show that the proposed machine is effective in reducing PM eddy loss and axial force by 60% and 35%, respectively.

  17. Diagnostic value of axial CT scan

    International Nuclear Information System (INIS)

    Kiuchi, Sousuke

    1983-01-01

    Axial CT scan was used to investigate the radiological details of the temporal bone of 33 patients with chronic otitis media, secondary cholesteatoma, sensorineural hearing loss, Meniere disease, vertigo, facial spasm, and neoplasma. The axial scans showed anatomic details of the temporal bone, and at the same time clearly demonstrated the extent of the soft-tissue masses in the middle ears, as well as the destructions of the ossicles. Bone changes of the anterior walls of the epitympanum and external auditory meatus were more clearly demonstrated than by coronary CT scan. However, the axial scan had the disadvantages in demonstrating the stapes, crista transversa, and the mastoid portion of the facial canal. (author)

  18. Improving the lattice axial vector current

    International Nuclear Information System (INIS)

    Horsley, R.; Perlt, H.; Schiller, A.; Zanotti, J.M.

    2015-11-01

    For Wilson and clover fermions traditional formulations of the axial vector current do not respect the continuum Ward identity which relates the divergence of that current to the pseudoscalar density. Here we propose to use a point-split or one-link axial vector current whose divergence exactly satisfies a lattice Ward identity, involving the pseudoscalar density and a number of irrelevant operators. We check in one-loop lattice perturbation theory with SLiNC fermion and gauge plaquette action that this is indeed the case including order O(a) effects. Including these operators the axial Ward identity remains renormalisation invariant. First preliminary results of a nonperturbative check of the Ward identity are also presented.

  19. Achados de tomografia computadorizada de alta resolução em pneumonia pelo vírus parainfluenza pós-transplante de medula óssea: relato de caso

    Directory of Open Access Journals (Sweden)

    Emerson L. Gasparetto

    2004-11-01

    Full Text Available RESUMO: Paciente feminina, de 19 anos, transplantada de medula óssea devido a leucemia mielóide crónica, apresentando tosse seca e coriza no 67.º dia após o procedimento. A radiografia de tórax não evidenciou alterações. A tomografia computadorizada de alta resolução do tórax revelou consolidação subsegmentar na periferia do lobo inferior esquerdo e áreas de redução da atenuação nos terços superior e médio dos pulmões. O lavado broncoalveolar demonstrou pesquisa positiva por imunoflorescência direta para anticorpos anti-vírus parainfluenza. Foi instituído tratamento com ribavirina aerolizada durante 10 dias, havendo melhoria clínico-radiológica do quadro infeccioso.REV PORT PNEUMOL 2004; X (6: 485-489 ABSTRACT: Nineteen year-old female patient, who underwent bone marrow transplantation because of chronic myelogenous leukemia, presented with dry cough and coriza sixty-seven days after the procedure. The chest radiograph was normal. The high resolution computed tomography showed a subsegmental air-space consolidation at the periphery of the left inferior lobe and areas of low attenuation at the superior and middle lung zones. The bronchoalveolar lavage demonstrated positive direct fluorescence antibody testing against parainfluenza virus. Treatment with aerolizated ribavirin was instituted during 10 days and the patient showed clinical-radiological improvement.REV PORT PNEUMOL 2004; X (6: 485-489 Palavras-chave: Vírus parainfluenza, tomografia computadorizada de alta resolução, transplante de medula óssea, Key-words: Parainfluenza virus, high resolution computed tomography, bone marrow transplantation

  20. Axial tomographic scanner

    International Nuclear Information System (INIS)

    1976-01-01

    An axial tomographic system is described comprising axial tomographic means for collecting sets of data corresponding to the transmission or absorption of a number of beams of penetrating radiation through a planar slice of an object. It includes means to locate an object to be analyzed, a source and detector for directing one or more beams of penetrating radiation through the object from the source to the detector, and means to rotate (and optionally translate) the source as well as means to process the collected sets of data. Data collection, data processing, and data display can each be conducted independently of each other. An additional advantage of the system described is that the raw data (i.e., the originally collected data) are not destroyed by the data processing but instead are retained intact for further reference or use, if needed

  1. Δ(1232) Axial Charge and Form Factors from Lattice QCD

    International Nuclear Information System (INIS)

    Alexandrou, Constantia; Gregory, Eric B.; Korzec, Tomasz; Koutsou, Giannis; Negele, John W.; Sato, Toru; Tsapalis, Antonios

    2011-01-01

    We present the first calculation on the Δ axial vector and pseudoscalar form factors using lattice QCD. Two Goldberger-Treiman relations are derived and examined. A combined chiral fit is performed to the nucleon axial charge, N to Δ axial transition coupling constant and Δ axial charge.

  2. Caracterización etiológica del síndrome de Lennox-Gastaut sintomático

    Directory of Open Access Journals (Sweden)

    Ileana Valdivia Álvarez

    2012-03-01

    Full Text Available Introducción: el síndrome de Lennox-Gastaut es una encefalopatía epiléptica dependiente de la edad, de gran severidad, por su farmacorresistencia y las discapacidades asociadas. Objetivos: caracterizar el síndrome de Lennox-Gastaut sintomático según sexo, edad de inicio y diagnóstico, tipo de crisis predominantes, hallazgos en neuroimagen y etiología. Métodos: estudio descriptivo, retrospectivo con una muestra de 36 pacientes egresados del servicio de neuropediatría del Hospital Pediátrico "Juan M. Márquez", con diagnóstico de síndrome de Lennox-Gastaut sintomático y que tuvieran estudios de neuroimagen (tomografía axial computarizada y resonancia magnética nuclear. Las variables cualitativas se describieron estadísticamente mediante frecuencias absolutas y cifras porcentuales. Para los porcentajes de interés, se calculó su intervalo de confianza con el 95 % de confiabilidad (IC 95 %. Resultados y conclusiones: el síndrome de Lennox-Gastaut sintomático fue más frecuente en varones, que comenzaron con epilepsia antes del año de edad, el 33 % presentó síndrome de West. Más del 60 % se diagnosticó antes de los 4 años de edad. Las crisis más frecuentes fueron las tónicas y atónicas de cuello. La tomografía axial computarizada permite localizar zonas de atrofia y pocas lesiones estructurales, que se precisan por resonancia magnética nuclear como alteraciones de la migración neuronal. Después de las malformaciones del sistema nervioso central, la causa más frecuente fue la hipoxia perinatal.

  3. Axial force measurement for esophageal function testing

    DEFF Research Database (Denmark)

    Gravesen, Flemming Holbæk; Funch-Jensen, Peter; Gregersen, Hans

    2009-01-01

    force (force in radial direction) whereas the bolus moves along the length of esophagus in a distal direction. Force measurements in the longitudinal (axial) direction provide a more direct measure of esophageal transport function. The technique used to record axial force has developed from external...... force transducers over in-vivo strain gauges of various sizes to electrical impedance based measurements. The amplitude and duration of the axial force has been shown to be as reliable as manometry. Normal, as well as abnormal, manometric recordings occur with normal bolus transit, which have been...... documented using imaging modalities such as radiography and scintigraphy. This inconsistency using manometry has also been documented by axial force recordings. This underlines the lack of information when diagnostics are based on manometry alone. Increasing the volume of a bag mounted on a probe...

  4. Two-dimensional nonlinear dynamics of an axially moving viscoelastic beam with time-dependent axial speed

    International Nuclear Information System (INIS)

    Ghayesh, Mergen H.; Amabili, Marco; Farokhi, Hamed

    2013-01-01

    In the present study, the coupled nonlinear dynamics of an axially moving viscoelastic beam with time-dependent axial speed is investigated employing a numerical technique. The equations of motion for both the transverse and longitudinal motions are obtained using Newton’s second law of motion and the constitutive relations. A two-parameter rheological model of the Kelvin–Voigt energy dissipation mechanism is employed in the modelling of the viscoelastic beam material, in which the material time derivative is used in the viscoelastic constitutive relation. The Galerkin method is then applied to the coupled nonlinear equations, which are in the form of partial differential equations, resulting in a set of nonlinear ordinary differential equations (ODEs) with time-dependent coefficients due to the axial acceleration. A change of variables is then introduced to this set of ODEs to transform them into a set of first-order ordinary differential equations. A variable step-size modified Rosenbrock method is used to conduct direct time integration upon this new set of first-order nonlinear ODEs. The mean axial speed and the amplitude of the speed variations, which are taken as bifurcation parameters, are varied, resulting in the bifurcation diagrams of Poincaré maps of the system. The dynamical characteristics of the system are examined more precisely via plotting time histories, phase-plane portraits, Poincaré sections, and fast Fourier transforms (FFTs)

  5. Detecção de fraturas radiculares em imagens de tomografia computadorizada de feixe cônico utilizando diferentes parâmetros de exposição e materiais intracanais

    OpenAIRE

    Pinto, Martina Gerlane de Oliveira

    2015-01-01

    O objetivo deste estudo foi avaliar a detecção de fraturas radiculares (FRs) em imagens de Tomografia Computadorizada de Feixe Cônico (TCFC) utilizando diferentes parâmetros de exposição e analisar a influência da guta- percha, do núcleo metálico fundido e do pino de fibra de vidro no diagnóstico das FRs, assim como a formação de artefatos em TCFC. Cento e sessenta dentes foram selecionados e divididos em quatro grupos de acordo com o material de preenchimento (sem guta-percha, com guta-perch...

  6. Stochastic quantization for the axial model

    International Nuclear Information System (INIS)

    Farina, C.; Montani, H.; Albuquerque, L.C.

    1991-01-01

    We use bosonization ideas to solve the axial model in the stochastic quantization framework. We obtain the fermion propagator of the theory decoupling directly the Langevin equation, instead of the Fokker-Planck equation. In the Appendix we calculate explicitly the anomalous divergence of the axial-vector current by using a regularization that does not break the Markovian character of the stochastic process

  7. Nonperturbative Aspects of Axial Vector Vertex

    Institute of Scientific and Technical Information of China (English)

    ZONG Hong-Shi; CHEN Xiang-Song; WANG Fan; CHANG Chao-Hsi; ZHAO En-Guang

    2002-01-01

    It is shown how the axial vector current of current quarks is related to that of constituent quarks within the framework of the global color symmetry model.Gluon dressing of the axial vector vertex and the quark self-energy functions are described by the inhomogeneous Bethe-Salpeter equation in the ladder approximation and the Schwinger Dyson equation in the rainbow approximation,respectively.

  8. Tumor neuroectodérmico primitivo renal. Reporte de un caso

    OpenAIRE

    Nestor Moisés Tineo Araque; Helen Daniela Uzcátegui Camacaro; Henrry Ramirez; Humberto Ruz

    2011-01-01

    El cáncer de riñón representa entre el 2 y 3% del total de las neoplasias malignas, encontrándose entre ellas el tumor neuroectodérmico (1,1% dentro del cáncer renal). En muchos casos el diagnóstico es tardío y se describe la triada clásica: dolor, hematuria y masa palpable. El ultrasonido y la tomografía axial computarizada son los métodos de diagnóstico más importantes y el éxito terapéutico se basa en la cirugía radical. Se presenta caso de paciente femenina de 23 años quien inicia enferm...

  9. Pielonefritis enfisematosa: Reporte de dos casos y revisión de la literatura.

    Directory of Open Access Journals (Sweden)

    Idalia Piedra Valoy

    2007-10-01

    Full Text Available Presentamos dos pacientes mujeres diabéticas con Pielonefritis enfisematosa bilateral atendidas en nuestro hospital. Ambas tenían más de 50 años de edad. El diagnóstico se realizó por la presencia de gas a nivel de ambos riñones, en la tomografía axial computarizada (TAC abdominal. Una de las pacientes fue sometida a nefrectomía bilateral y la otra a nefrectomía derecha. Ambas pacientes tuvieron mala evolución pese al tratamiento antibiótico y quirúrgico. Debido a su alta mortalidad hacemos énfasis en el diagnóstico y tratamiento precoz. (Rev Med Hered 2007;18:212-217.

  10. LINFOMAS PULMONARES: CORRELAÇÃO DA TOMOGRAFIA COMPUTADORIZADA DE ALTA RESOLUÇÃO COM A ANATOMOPATOLOGIA

    Directory of Open Access Journals (Sweden)

    Marchiori Edson

    2002-01-01

    Full Text Available Neste trabalho são descritos os aspectos tomográficos de alta resolução dos linfomas pulmonares e feita correlação com os achados anatomopatológicos. Com este objetivo, foram revisados as tomografias computadorizadas de alta resolução do tórax e os dados histopatológicos de dez pacientes com diagnóstico confirmado de linfoma não-Hodgkin ou de doença de Hodgkin. Os resultados obtidos foram confrontados com os descritos na literatura. Os achados radiológicos mais comumente vistos neste estudo foram as consolidações parenquimatosas, localizadas, com broncogramas aéreos de permeio (n = 8. Em menor freqüência, foram encontrados múltiplos nódulos parenquimatosos (n = 4, espessamento peribroncovascular (n = 3 e opacidades em vidro fosco (n = 2. Na correlação com a anatomia patológica, as consolidações corresponderam a preenchimento alveolar por células neoplásicas, o espessamento peribroncovascular se deveu a infiltração das bainhas peribroncovasculares por células linfomatosas e a atenuação em vidro fosco se associou com infiltração dos septos alveolares por tais células.

  11. Conservative axial burnup distributions for actinide-only burnup credit

    International Nuclear Information System (INIS)

    Kang, C.; Lancaster, D.

    1997-11-01

    Unlike the fresh fuel approach, which assumes the initial isotopic compositions for criticality analyses, any burnup credit methodology must address the proper treatment of axial burnup distributions. A straightforward way of treating a given axial burnup distribution is to segment the fuel assembly into multiple meshes and to model each burnup mesh with the corresponding isotopic compositions. Although this approach represents a significant increase in modeling efforts compared to the uniform average burnup approach, it can adequately determine the reactivity effect of the axial burnup distribution. A major consideration is what axial burnup distributions are appropriate for use in light of many possible distributions depending on core operating conditions and histories. This paper summarizes criticality analyses performed to determine conservative axial burnup distributions. The conservative axial burnup distributions presented in this paper are included in the Topical Report on Actinide-Only Burnup Credit for Pressurized Water Reactor Spent Nuclear Fuel Packages, Revision 1 submitted in May 1997 by the US Department of Energy (DOE) to the US Nuclear Regulatory Commission (NRC). When approved by NRC, the conservative axial burnup distributions may be used to model PWR spent nuclear fuel for the purpose of gaining actinide only burnup credit

  12. Avaliação tomográfica dos pedículos vertebrais no tratamento cirúrgico dos pacientes com escoliose idiopática do adolescente Evaluación de tomografía computarizada de pedículos vertebrales nel tratamiento quirúrgico de escoliosis idiopática del adolescente Computed tomography scan evaluation of vertebral pedicles for surgical treatment of adolescent idiopathic scoliosis

    Directory of Open Access Journals (Sweden)

    Alceu Gomes Chueire

    2012-12-01

    Full Text Available OBJETIVO: Determinar através de cortes tomográficos e reconstrução tridimensional a incidência de mal posicionamento de parafusos em pacientes submetidos ao tratamento cirúrgico da Escoliose idiopática do adolescente. MÉTODOS: Foram analisados exames tomográficos de 8 pacientes, tratados cirurgicamente no Hospital de Base de São José do Rio Preto-SP, realizada instrumentação posterior partindo de T2 /T4 a L4/L5 totalizando 164 parafusos. RESULTADOS: 32,9% (n=54 apresentavam posicionamento com risco potencial,ou seja desvio acima de 2 milímetros, sendo 20,1% (n=33 com invasão lateral, 9,1% (n=15 com invasão medial, 3,6 %(n=6 com invasão anterior. Dos parafusos que ofereciam risco potencial a relação com aspecto da curva foi de 46% (n=25 na concavidade, 35% (n=19 na convexidade e 19% (n=10 em vértebras adjacentes a curva. CONCLUSÃO: Os limites de penetração aceitáveis, assim como os métodos de mensuração ainda não foram padronizados, a técnica "free hand' mostrou-se segura, apesar da violação dos pedículos. A tomografia computadorizada pré-operatória, auxilia no planejamento cirúrgico e na redução das complicações.OBJETIVO: Evaluar mediante tomografía computarizada tridimensional de reconstrucción, una mala posición de los tornillos de pedículo en pacientes con escoliosis idiopática del adolescente. MÉTODOS: Se analizó cortes de tomografía computarizada de 8 pacientes sometidos a tratamiento quirúrgico en el Hospital de Base de São José do Rio Preto-SP, que se llevaron a cabo la fusión vertebral posterior de T2/T4 a L4/L5, 164 tornillos se insertaron. RESULTADOS: 32,9% (n = 54 fueron mal colocados que ofrecen riesgo potencial, que se consideraba una desviación de 2 mm, 20,1% (n = 33, la invasión lateral, el 9,1% (n = 15 invasión medial, 3,6 % (n = 6 la invasión anterior. De los tornillos mal colocados el 46% (n = 25 fueron en la concavidad, el 35% (n = 19 en la convexidad y el 19% (n = 10 se

  13. Cladding axial elongation models for FRAP-T6

    International Nuclear Information System (INIS)

    Shah, V.N.; Carlson, E.R.; Berna, G.A.

    1983-01-01

    This paper presents a description of the cladding axial elongation models developed at the Idaho National Engineering Laboratory (INEL) for use by the FRAP-T6 computer code in analyzing the response of fuel rods during reactor transients in light water reactors (LWR). The FRAP-T6 code contains models (FRACAS-II subcode) that analyze the structural response of a fuel rod including pellet-cladding-mechanical-interaction (PCMI). Recently, four models were incorporated into FRACAS-II to calculate cladding axial deformation: (a) axial PCMI, (b) trapped fuel stack, (c) fuel relocation, and (d) effective fuel thermal expansion. Comparisons of cladding axial elongation measurements from two experiments with the corresponding FRAP-T6 calculations are presented

  14. Aplicación de metodología de modelado 3D utilizando Tomografías Computarizadas para su análisis numérico

    Directory of Open Access Journals (Sweden)

    Ariel Fuerte Hernández

    2014-01-01

    Full Text Available Este trabajo presenta una metodología para la generación de un modelo del segmento lumbar porcino y humano L4-L5 a partir de Tomografías Computarizadas (TC. El uso de la TC como herramienta de biomodelado es una técnica que actualmente es muy usada en el desarrollo de análisis numéricos computacionales mediante programas de Análisis de Elemento Finito (AEF, lo que permite visualizar y analizar estructuras anatómicas simples y/o complejas. Por lo que, la relevancia de este trabajo radica en el hecho de la generación de análisis numéricos biomecánicos con resultados muy cercanos a los análisis experimentales, creando soluciones médicas en el diseño de dispositivos protésicos. Los resultados numéricos muestran una concentración de esfuerzos en el disco intervertebral justo en la zona de las placas terminales, tanto en el caso humano como en el porcino, lo que concuerda con análisis experimentales previos. De este modo, se concluye que los resultados obtenidos mediante esta técnica validan análisis experimentales previos, sin embargo, es necesario tomar en cuenta las características del comportamiento mecánico de los diferentes tejidos biológicos que componen la columna lumbar.

  15. Tomografia Computadorizada de crânio em perícias criminais: uma grande aliada

    Directory of Open Access Journals (Sweden)

    Márcio Gleidson Ribeiro Dias

    2016-11-01

    Full Text Available O presente estudo trata-se de uma revisão descritiva da literatura sobre as principais vantagens da Tomografia Computadorizada (TC de crânio na área de Criminologia. Para a revisão literária foram utilizados artigos e dissertações recentes publicados entre 2007 e 2016, livros de imagenologia e medicina legal. A partir dos dados obtidos na revisão literária, nós realizamos uma descrição sobre a TC e sua evolução ao longo dos anos, suas vantagens e aplicações em perícias criminais. Destacamos a importância do laudo pericial, a responsabilidade do perito criminal, a fisiopatologia do trauma cranioencefálico e a sua relação com a violência urbana.Entre as vantagens da virtópsia em relação aos métodos tradicionais destacam-se a preservação do corpo, o arquivamento das imagens e a capacidade de identificação de vítimas através de imagens comparativas ante mortem e post mortem. Assim, a TC tem se tornado cada vez mais presente nas investigações criminais como uma tecnologia de baixo custo que é capaz de localizar, quantificar e evidenciar o trajeto de projéteis, auxiliando na identificação de cadáveres e causas da morte.

  16. Tomografia computadorizada das células etmoidais intra e extramurais: ensaio iconográfico

    Directory of Open Access Journals (Sweden)

    Fabrício Guimarães Gonçalves

    2011-10-01

    Full Text Available O desenvolvimento dos seios paranasais é um processo intricado que se inicia na vida intrauterina e termina na idade adulta. Dos seios da face, as células etmoidais são provavelmente as estruturas mais complexas e as que estão associadas com o maior número de variantes da normalidade. Variações no padrão de pneumatização das células etmoidais podem ser divididas em intra ou extramurais. Intramurais são aquelas que ao se desenvolverem mantêm contato com o labirinto etmoidal, e extramurais as que se desenvolvem isoladamente. A tomografia computadorizada é a ferramenta mais útil na avaliação de processos inflamatórios dos seios paranasais. De igual modo, ela é importante para o planejamento pré-operatório e controle pós-operatório, pois possibilita grande detalhe anatômico das estruturas normais e detecção precisa de suas variantes. Neste ensaio iconográfico os autores descrevem as principais variantes da normalidade do labirinto etmoidal e suas relações com estruturas adjacentes. Cirurgias endoscópicas para o tratamento de afecções dos seios paranasais têm-se tornado cada vez menos invasivas, o que certamente aumentará a demanda por relatórios de imagem cada vez mais ricos em detalhes desta região.

  17. Nasoangiofibroma juvenil: concordância interobservadores no estadiamento por tomografia computadorizada Juvenile nasopharyngeal angiofibroma: interobserver agreement in cancer staging using computed tomography

    Directory of Open Access Journals (Sweden)

    Jefferson Luiz Gusso

    2001-08-01

    Full Text Available Com o advento da tomografia computadorizada, a avaliação dos locais de acometimento e extensão do nasoangiofibroma juvenil tornou-se mais precisa, o que facilitou o correto estadiamento pré-operatório. O objetivo deste trabalho é avaliar a concordância interobservadores, por meio da análise por tomografia computadorizada, de 15 casos de nasoangiofibroma juvenil em relação à extensão para locais relacionados com altos índices de recidivas. Todos os pacientes eram do sexo masculino, com idade média de 15,8 anos. A análise da concordância entre os observadores quanto à extensão e envolvimento da fossa infratemporal, seios esfenóide e cavernoso e fossa craniana média foi excelente, em relação à fissura orbitária superior foi boa e em relação à base do processo pterigóide e fossa craniana anterior foi ruim. Concluiu-se que a análise apresenta alta concordância entre os observadores para os locais estabelecidos, com exceção da base do processo pterigóide e da fossa craniana anterior.The advent of computed tomography permitted a much more precise evaluation of tumor localization, thus facilitating presurgical staging. The objective of this study was to evaluate the interobserver agreement on the analysis of computed tomography scans of 15 patients with juvenile nasopharyngeal angiofibroma, regarding assessment of tumor extension to sites of high recurrence rate. All patients were male and had a mean age of 15.8 years. The results of the interobserver agreement analysis regarding tumor invasion and extension to the infratemporal fossa, cavernous sinus, sphenoid sinus and medium cranial fossa were excellent. Identification of involvement of the superior orbital fissure was considered good. Interobserver agreement regarding tumor extension to the base of pterigoid process and anterior cranial fossa was considered poor. We concluded that there is a very good interobserver agreement on the evaluation of the established

  18. Esclerose sistêmica progressiva: aspectos na tomografia computadorizada de alta resolução Progressive systemic sclerosis: high-resolution computed tomography findings

    Directory of Open Access Journals (Sweden)

    Emerson L. Gasparetto

    2005-09-01

    Full Text Available OBJETIVO: Descrever os achados de tomografia computadorizada de alta resolução de pacientes com esclerose sistêmica pulmonar, independentemente dos sintomas respiratórios. MATERIAIS E MÉTODOS: Foram revisados 73 exames de tomografia computadorizada de alta resolução de 44 pacientes com diagnóstico de esclerodermia estabelecido através de critérios clínicos e laboratoriais. Os exames foram revisados por dois radiologistas, que estabeleceram os achados por consenso. RESULTADOS: Em 91,8% (n = 67 dos exames observaram-se alterações. Os principais achados foram lesões de padrão reticular (90,4%, opacidades em vidro-fosco (63%, bronquiectasias e bronquiolectasias de tração (56,2%, dilatação esofagiana (46,6%, faveolamento (28,8% e sinais de hipertensão pulmonar (15,6%. Na maioria dos casos as lesões eram bilaterais (89% e simétricas (58,5%. Quanto à localização, houve predomínio de lesões basais (91,2% e periféricas (92,2%. CONCLUSÃO: A esclerose sistêmica progressiva acarreta fibrose pulmonar na maioria dos pacientes, caracterizada principalmente por lesão reticular basal e periférica.OBJECTIVE: To describe the high-resolution computed tomography findings in the lung of patients with systemic sclerosis, independently of the respiratory symptoms. MATERIALS AND METHODS: Seventy-three high-resolution computed tomography scans of 44 patients with clinical diagnosis of systemic sclerosis were reviewed and defined by the consensus of two radiologists. RESULTS: Abnormalities were seen in 91.8% (n = 67 of the scans. The most frequent findings were reticular pattern (90.4%, ground-glass opacities (63%, traction bronchiectasis and bronchiolectasis (56.2%, esophageal dilatation (46.6%, honeycombing pattern (28.8% and signs of pulmonary hypertension (15.6%. In most cases the lesions were bilateral (89% and symmetrical (58.5%. The lesions were predominantly located in the basal (91.2% and peripheral (92.2% regions. CONCLUSION: In

  19. Development of submersible axial pump for wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Jeong Eui [Kangwon Nat' l Univ., Chuncheon (Korea, Republic of)

    2013-02-15

    This study was performed to develop a high efficiency submersible axial pump for concentration wastewater treatment. To do this, we simulated the effect of some parameters such as the axial twist angle of a blade({beta}), the radial twist angle of a blade({alpha}) and the length of a blade ({iota}) on pump efficiency using commercial code, ANSYS CFX and BladeGen. The results showed that the axial twist angle of a blade({beta}) was the most sensible parameter on the pump efficiency. And the pump efficiency had a maximum at {beta}=20.deg, {alpha}=110.deg and {iota}=240mm.

  20. Axial displacements in external and internal implant-abutment connection.

    Science.gov (United States)

    Lee, Ji-Hye; Kim, Dae-Gon; Park, Chan-Jin; Cho, Lee-Ra

    2014-02-01

    The purpose of this study was to evaluate the axial displacement of the abutments during clinical procedures by the tightening torque and cyclic loading. Two different implant-abutment connection systems were used (external butt joint connection [EXT]; internal tapered conical connection [INT]). The master casts with two implant replicas, angulated 10° from each other, were fabricated for each implant connection system. Four types of impression copings were assembled and tightened with the corresponding implants (hex transfer impression coping, non-hex transfer impression coping, hex pick-up impression coping, non-hex pick-up impression coping). Resin splinted abutments and final prosthesis were assembled. The axial displacement was measured from the length of each assembly, which was evaluated repeatedly, after 30 Ncm torque tightening. After 250 N cyclic loading of final prosthesis for 1,000,000 cycles, additional axial displacement was recorded. The mean axial displacement was statistically analyzed (repeated measured ANOVA). There was more axial displacement in the INT group than that of the EXT group in impression copings, resin splinted abutments, and final prosthesis. Less axial displacement was found at 1-piece non-hex transfer type impression coping than other type of impression copings in the INT group. There was more axial displacement at the final prosthesis than resin splinted abutments in the INT and the EXT groups. After 250 N cyclic loading of final prosthesis, the INT group showed more axial displacement than that of the EXT group. Internal tapered conical connection demonstrated a varying amount of axial displacement with tightening torque and cyclic loading. © 2012 John Wiley & Sons A/S. Published by Blackwell Publishing Ltd.

  1. High Precision Axial Coordinate Readout for an Axial 3-D PET Detector Module using a Wave Length Shifter Strip Matrix

    CERN Document Server

    Braem, André; Joram, C; Séguinot, Jacques; Weilhammer, P; De Leo, R; Nappi, E; Lustermann, W; Schinzel, D; Johnson, I; Renker, D; Albrecht, S

    2007-01-01

    We describe a novel method to extract the axial coordinate from a matrix of long axially oriented crystals, which is based on wavelength shifting plastic strips. The method allows building compact 3-D axial gamma detector modules for PET scanners with excellent 3-dimensional spatial, timing and energy resolution while keeping the number of readout channels reasonably low. A voxel resolution of about 10 mm3 is expected. We assess the performance of the method in two independent ways, using classical PMTs and G-APDs to read out the LYSO (LSO) scintillation crystals and the wavelength shifting strips. We observe yields in excess of 35 photoelectrons from the strips for a 511 keV gamma and reconstruct the axial coordinate with a precision of about 2.5 mm (FWHM).

  2. Dual-detection confocal fluorescence microscopy: fluorescence axial imaging without axial scanning.

    Science.gov (United States)

    Lee, Dong-Ryoung; Kim, Young-Duk; Gweon, Dae-Gab; Yoo, Hongki

    2013-07-29

    We propose a new method for high-speed, three-dimensional (3-D) fluorescence imaging, which we refer to as dual-detection confocal fluorescence microscopy (DDCFM). In contrast to conventional beam-scanning confocal fluorescence microscopy, where the focal spot must be scanned either optically or mechanically over a sample volume to reconstruct a 3-D image, DDCFM can obtain the depth of a fluorescent emitter without depth scanning. DDCFM comprises two photodetectors, each with a pinhole of different size, in the confocal detection system. Axial information on fluorescent emitters can be measured by the axial response curve through the ratio of intensity signals. DDCFM can rapidly acquire a 3-D fluorescent image from a single two-dimensional scan with less phototoxicity and photobleaching than confocal fluorescence microscopy because no mechanical depth scans are needed. We demonstrated the feasibility of the proposed method by phantom studies.

  3. Health and imaging outcomes in axial spondyloarthritis

    NARCIS (Netherlands)

    Machado, P.M.

    2016-01-01

    This thesis focuses on the assessment and monitoring of health and imaging outcomes in axial spondyloarthritis (SpA) and the relationship between these outcomes. Four major contributions to the understanding and management of axial SpA were made: 1) the improvement and facilitation of the assessment

  4. DIGITALIZACIÓN 3D DEL RODETE DE UN COMPRESOR CENTRÍFUGO: UN PROCEDIMIENTO ALTERNATIVO 3D-DIGITIZING OF A CENTRIFUGAL COMPRESSOR'S IMPELLER: AN ALTERNATIVE PROCEDURE

    Directory of Open Access Journals (Sweden)

    Jairo Andrés Acosta Rojas

    2007-12-01

    Full Text Available En la digitalización 3D del rodete del compresor centrífugo de un turbo cargador HT3B, se evaluaron numerosas metodologías que permitieran reproducir su geometría satisfactoriamente, de modo que a partir del modelo virtual obtenido se pudiera llevar a cabo una simulación computacional de flujo en el compresor centrífugo. Tras analizar dichas metodologías se decidió que la toma de tomografías axiales computarizadas era la más indicada, a pesar de que requirió previamente la construcción de un modelo en acrílico del rodete. Una vez se contó con las tomografías axiales computarizadas del rodete, se procedió a construir el modelo virtual del mismo usando un programa CAD 3D, integrando una metodología analítica para la generación de la geometría de los álabes del rodete de un compresor centrífugo, con la información metrológica adquirida a través de las tomografías. El modelo virtual del rodete presentó características aptas para el posterior trabajo de simulación, demostrando que el procedimiento planteado constituye una alternativa viable para la digitalización 3D de piezas mecánicas de alta complejidad.In the 3D digitizing of an HT3B turbocharger's centrifugal compressor's impeller, several methodologies were evaluated, reproducing its shape in such a way, that the obtained virtual model could be used to perform a computational flow simulation in the whole centrifugal compressor. After analyzing these methodologies, computerized axial tomographies were chosen as the most suitable methodology, despite requiring the previous construction of an impeller's acrylic-made model. Once the impeller's computerized axial tomographies had been taken, the generation of the virtual model was performed by software CAD 3D, by integrating an analytic methodology for the impeller's vanes' geometrical shape generation, with the metrological information extracted from the tomographies. The virtual model generated presented

  5. sizing of wind powered axial flux permanent magnet alternator using

    African Journals Online (AJOL)

    user

    2016-10-04

    Oct 4, 2016 ... Keywords: Wind-Power, Axial flux, Axial Flux Permanent Machines (AFPM), Axial Flux Permanent Magnet ... energy for power generation, a high constraint is the .... arrangements as Single-Rotor Single-Stator Structure.

  6. Buoyant Helical Twin-Axial Wire Antenna

    Science.gov (United States)

    2016-11-15

    February 2017 The below identified patent application is available for licensing. Requests for information should be addressed to...300169 1 of 9 BUOYANT HELICAL TWIN-AXIAL WIRE ANTENNA CROSS REFERENCE TO OTHER PATENT APPLICATIONS [0001] This application is a divisional...application and claims the benefit of the filing date of United States Patent Application No. 14/280,889; filed on May 19, 2014; and entitled “Twin-Axial

  7. Axial forces in centrifugal compressor couplings

    Science.gov (United States)

    Ivanov, A. N.; Ivanov, N. M.; Yun, V. K.

    2017-08-01

    The article presents the results of the theoretical and experimental investigation of axial forces arising in the toothed and plate couplings of centrifugal compressor shaft lines. Additional loads on the thrust bearing are considered that can develop in the toothed couplings as a result of coupled rotors misalignment. Design relationships to evaluate the level of axial forces and recommendations for their reduction in the operating conditions are given.

  8. Chiral filter, axial charges and Gamow-Teller strengths

    International Nuclear Information System (INIS)

    Rho, M.

    1983-09-01

    The different ways that nuclear matter responds to the weak axial-vector current are interpreted in terms of modification of the ''vacuum'' in baryon-rich environments. The notion of ''chiral filter'' is introduced. Use of a ward identity is suggested. The Gamow-Teller quenching and the enhanced axial charge in O + O - transitions follow from this. I also discuss briefly possible relevance of the nucleon as a topological soliton configuration to the global property of nuclear axial response functions

  9. Fuel rod with axial regions of annular and standard fuel pellets

    International Nuclear Information System (INIS)

    Freeman, T.R.

    1991-01-01

    This patent describes a fuel rod for use in a nuclear reactor fuel assembly. It comprises: an elongated hollow cladding tube; a pair of end plugs connected to and sealing the cladding tube at opposite ends of thereof; and an axial stack of fuel pellets contained in and extending between the end plugs at the opposite ends of the tube, all of the fuel pellets contained in the tube being composed of fissile material being enriched above the level of natural enrichment; the fuel pellets in the stack thereof being provided in an arrangement of axial regions. The arrangement of axial regions including a pair of first axial regions defined respectively at the opposite ends of the pellet stack adjacent to the respective end plugs. The pellets in the first axial regions being identical in number and having annular configurations with an annulus of a first void size. The arrangement of axial regions also including another axial region defined between the first axial regions, some of the pellets in the another axial region having solid configurations

  10. Chiral lattice fermions, minimal doubling, and the axial anomaly

    International Nuclear Information System (INIS)

    Tiburzi, B. C.

    2010-01-01

    Exact chiral symmetry at finite lattice spacing would preclude the axial anomaly. In order to describe a continuum quantum field theory of Dirac fermions, lattice actions with purported exact chiral symmetry must break the flavor-singlet axial symmetry. We demonstrate that this is indeed the case by using a minimally doubled fermion action. For simplicity, we consider the Abelian axial anomaly in two dimensions. At finite lattice spacing and with gauge interactions, the axial anomaly arises from nonconservation of the flavor-singlet current. Similar nonconservation also leads to the axial anomaly in the case of the naieve lattice action. For minimally doubled actions, however, fine-tuning of the action and axial current is necessary to arrive at the anomaly. Conservation of the flavor nonsinglet vector current additionally requires the current to be fine-tuned. Finally, we determine that the chiral projection of a minimally doubled fermion action can be used to arrive at a lattice theory with an undoubled Dirac fermion possessing the correct anomaly in the continuum limit.

  11. Axial Myopia and its Influence on Diabetic Retinopathy

    International Nuclear Information System (INIS)

    Tayyab, H.; Haider, M. A.; Bukhari, S. A. H.

    2014-01-01

    Objective: To evaluate the correlation between axial myopia and diabetic retinopathy. Study Design: Cross-sectional study. Place and Duration of Study: Eye Department of Postgraduate Medical Institute, Lahore General Hospital, from August 2012 to February 2013. Methodology: A total of 258 participants suffering from type-2 diabetic retinopathy were included. Axial length was measured by two optometrists using contact type ultrasound biometer. Colored retinal photographs, red free retinal photographs and Fundus Fluorescein Angiography (FFA) were performed on all patients using standard fundus camera. All fundus photographs and angiograms were independently reviewed and graded by two qualified vitreoretinal fellows. Results: Out of 258 patients, 163 were males (63.2%) and 95 (36.8%) were females. Average age of patients was 56.30 +- 7.57 years. Average axial length of right and left eyes were 23.16 mm and 23.15 mm respectively. There was statistically significant negative correlation between axial length and severity of diabetic retinopathy in the right eye, (Spearman correlation = -0.511, p = 0.0001) as well as the left eye (Spearman correlation = -0.522, p = 0.0001). Conclusion: There is a protective influence of longer axial length of globe on the stage and severity of diabetic retinopathy. This study may help in modifying the screening protocol for diabetic retinopathy amongst patients of differing axial lengths. (author)

  12. Tuberculose pulmonar: achados na tomografia computadorizada de alta resolução do tórax em pacientes com doença em atividade comprovada bacteriologicamente Pulmonary tuberculosis: findings on high resolution computerized tomography of active disease on patients with bacteriological confirmation

    Directory of Open Access Journals (Sweden)

    CRISTIANE ALÓ CAMPOS

    2002-01-01

    Full Text Available Objetivo: Descrever os achados em pacientes com tuberculose pulmonar em atividade na tomografia computadorizada de alta resolução e o padrão de distribuição das lesões pelo parênquima pulmonar. Casuística e método: Foram analisadas retrospectivamente as tomografias de alta resolução de 42 pacientes com diagnóstico bacteriológico de tuberculose pulmonar ou forte suspeita clínica, com posterior confirmação bacteriológica. Resultados: Os principais sinais sugestivos de atividade encontrados foram nódulos do espaço aéreo (83%, nódulos centrolobulares (74%, aspecto de árvore em brotamento (67%, cavitações (67%, espessamento das paredes brônquicas (55%, consolidações (48%, opacidade em vidro fosco (21%, e espessamento do interstício pulmonar (9%. Conclusão: A tomografia computadorizada de alta resolução do tórax pode sugerir fortemente atividade da doença, sendo particularmente útil nos pacientes com baciloscopias negativas e/ou radiografias indeterminadas, permitindo a instituição de tratamento adequado, antes mesmo do crescimento da micobactéria em meio de cultura.Background: The aim of this study was to describe the signs of active tuberculosis in patients submitted to high resolution computerized tomography and the distribution of lesions along the pulmonary parenchyma. Material and methods: The high resolution CTs performed on 42 patients with tuberculosis either bacteriologically diagnosed or clinical suspected and later confirmed by bacteriological tests were studied. Results: The signs of disease activity observed were airspace nodule (83%, centrilobular nodule (74%, tree-in-bud pattern (67%, cavitations (67%, bronchial thickening (55%, parenchymal consolidations (48%, ground glass opacity (21% and thickening of the inter and intralobular septa (9%. Conclusion: High resolution computed tomography can be strongly suggestive of disease activity, is particularly helpful in patients with negative smear and

  13. Transitions in axial morphology along the Southeast Indian Ridge

    Science.gov (United States)

    Ma, Ying; Cochran, James R.

    1996-07-01

    Shipboard bathymetric and magnetic profiles across the Southeast Indian Ridge (SEIR) were analyzed in order to examine the nature of along-axis variations in axial morphology at this intermediate spreading rate ridge. Three types of axial morphology are observed along the SEIR: an axial high, a shallow (200-700 m deep) axial valley and a deep (>1000 m deep) axial valley. An axial high is found to the east of the Australian-Antarctic Discordance (AAD) (east of 128°E) and between 82°E and 104°E. A shallow rift valley is found from 104°E to 114°E and from 82°E westward past the Amerstdam/St. Paul hotspot (ASP) to about 30°S, 75°E. Deep rift valleys are found from 114°E to 128°E in the vicinity of the AAD and from the Indian Ocean Triple Junction (IOTJ) at 25°S, 70°E to about 30°S, 75°E. The transition near 30°S occurs in an area of constant zero-age depth and does not appear to result from an increase in mantle temperature. It could be the result of the rapid increase in spreading rate along that portion of the SEIR. The most likely cause of the other transitions in axial morphology is variations in mantle temperature. The transitions between the different types of axial morphology are well defined and occur over a limited distance. Transitions in axial morphology are accompanied by significant changes in ridge flank topographic roughness. The transitions from axial valleys to axial highs are also accompanied by changes in the amplitude of the seafloor magnetic anomalies. Our observations suggest that there are distinct modes rather than a continuum of axial morphology on the SEIR and that there appears to be a "threshold" mechanism for a rapid change between different states of axial morphology. The ASP has only a limited influence on the SEIR. The ridge axis is marked by an axial valley for the entire distance from the IOTJ up to and past the ASP. The ridge axis becomes shallower as the ASP is approached from the northwest but only by about 300 m over

  14. Lesões traumáticas do parênquima pulmonar: aspectos na tomografia computadorizada Traumatic lung lesions: computed tomography findings

    Directory of Open Access Journals (Sweden)

    Alessandro Severo Alves de Melo

    2003-06-01

    Full Text Available As lesões pulmonares são achados freqüentes no trauma torácico, sendo cada vez mais diagnosticadas pela tomografia computadorizada, em especial pelo rápido tempo de aquisição decorrente da técnica helicoidal, que permite a avaliação de pacientes em estado grave, possibilitando a adoção de conduta terapêutica eficiente. Os autores estudaram 150 pacientes vítimas de trauma torácico submetidos a tomografia computadorizada, que apresentaram lesões pulmonares, representadas por contusões, atelectasias, lacerações e hematomas pulmonares. As contusões pulmonares se caracterizaram por consolidações e atenuação em vidro fosco, sendo as lesões pulmonares mais comuns. As atelectasias foram observadas com os padrões subsegmentar e compressiva, e foram a segunda lesão mais comum. As lacerações se apresentaram como consolidações com ar ou nível líquido no interior. Os hematomas pulmonares representaram a lesão pulmonar mais rara, presentes em apenas cinco casos, caracterizados por opacidades arredondadas. Neste trabalho o trauma torácico fechado predominou, com 120 casos, enquanto o trauma aberto ocorreu em 30 casos. As causas de trauma fechado, em ordem decrescente de freqüência, foram: colisão automobilística, atropelamento, queda de altura, acidente de motocicleta e espancamento. A forma penetrante de traumatismo torácico decorreu de duas causas de agressão: lesão por arma de fogo e lesão por arma branca.Traumatic lesions of the lung are common findings in patients with thoracic trauma. These lesions are increasingly diagnosed using computed tomography, mostly due to the fast acquisition time helical techniques that allow evaluation of critically ill patients and an efficient therapeutic management. The authors studied 150 patients with thoracic trauma submitted to computed tomography that demonstrated lung contusions, atelectasies, lacerations and hematomas. Lung contusions were the most frequent lesions

  15. The Axially Symmetric One-Monopole

    International Nuclear Information System (INIS)

    Wong, K.-M.; Teh, Rosy

    2009-01-01

    We present new classical generalized one-monopole solution of the SU(2) Yang-Mills-Higgs theory with the Higgs field in the adjoint representation. We show that this solution with θ-winding number m = 1 and φ-winding number n = 1 is an axially symmetric generalization of the 't Hooft-Polyakov one-monopole. We construct this axially symmetric one-monopole solution by generalizing the large distance asymptotic solutions of the 't Hooft-Polyakov one-monopole to the Jacobi elliptic functions and solving the second order equations of motion numerically when the Higgs potential is vanishing. This solution is a non-BPS solution.

  16. «FLARES» IN AXIAL SPONDYLOARTHRITIS

    Directory of Open Access Journals (Sweden)

    Sh. F. Erdes

    2016-01-01

    Full Text Available The clear definition of the concept of «flare in axial spondyloarthritis» is of paramount importance for clinical trials and routine practice in particular. It will be able to unify the characteristics of outcomes over a particular period of time on the one hand and to standardize therapeutic approaches on the other. On 4 February 2016, the journal Annals of Rheumatic Diseases published the on-line paper «Preliminary definitions of 'flare' in axial spondyloarthritis, based on pain, BASDAI and ASDAS-CRP: an ASAS initiative» by L. Gossec et al., which was devoted to this topic.

  17. Análise de dentição mista: tomografia versus predição e medida radiográfica Mixed-dentition analysis: tomography versus radiographic prediction and measurement

    Directory of Open Access Journals (Sweden)

    Letícia Guilherme Felício

    2010-10-01

    Full Text Available OBJETIVO: o objetivo dos autores desse estudo foi comparar o método de análise de dentição mista que utiliza tomografia computadorizada de feixe cônico para avaliar os diâmetros dos dentes intraósseos com os métodos de Moyers, Tanaka-Johnston e radiografias oblíquas em 45º. MÉTODOS: foram realizadas medidas, na arcada inferior, dos diâmetros mesiodistais dos incisivos permanentes irrompidos, nos modelos de gesso com auxílio de paquímetro digital e estimativa do tamanho de pré-molares e caninos permanentes ainda não irrompidos utilizando-se a tabela de Moyers e a fórmula de predição de Tanaka-Johnston. Nas radiografias oblíquas em 45º, caninos e pré-molares foram medidos utilizando-se o mesmo instrumento. Nas tomografias, as mesmas unidades dentárias foram aferidas por meio de ferramentas do programa Dolphin. RESULTADOS: a análise estatística revelou elevada concordância entre o método tomográfico e o radiográfico, e baixa concordância entre o tomográfico e os demais avaliados. CONCLUSÃO: a tomografia computadorizada de feixe cônico mostrou-se confiável para análise da dentição mista e apresenta algumas vantagens em relação aos métodos comparados: a observação e mensuração dos dentes intraósseos individualmente, com a possibilidade, contudo, de visualizá-los sob diferentes perspectivas e sem superposição de estruturas anatômicas.OBJECTIVE: The aim of this study was to evaluate the method for mixed-dentition analysis using Cone-Beam Computed Tomography for assessing the diameter of intra-osseous teeth and compare the results with those obtained by Moyers, Tanaka-Johnston, and 45-degree oblique radiographs. METHODS: Measurements of mesial-distal diameters of erupted lower permanent incisors were made on plaster cast models by using a digital calliper, whereas assessment of the size of non-erupted permanent pre-molars and canines was performed by using Moyer's table and Tanaka-Johnston's prediction

  18. Edema pulmonar hidrostático: aspectos na tomografia computadorizada de alta resolução Hydrostatic pulmonary edema: high-resolution computed tomography aspects

    Directory of Open Access Journals (Sweden)

    Cláudia Maria Cunha Ribeiro

    2006-12-01

    Full Text Available OBJETIVO: A proposta deste estudo foi caracterizar por meio de tomografia computadorizada de alta resolução do tórax as principais alterações pulmonares do edema pulmonar hidrostático. MÉTODOS: Foram analisadas, retrospectivamente, as tomografias de quinze pacientes com quadro clínico de edema pulmonar hidrostático, divididos em cinco principais grupos etiológicos: insuficiência cardíaca congestiva, valvulopatia mitral aguda, infarto agudo do miocárdio, miocardite e mediastinite fibrosante, tendo sido sete pacientes classificados no primeiro grupo e dois em cada um dos demais. RESULTADOS: Os principais achados do edema hidrostático foram opacidades em vidro fosco (100%, espessamento dos septos interlobulares (100%, derrame pleural (87% e espessamento do interstício peribroncovascular (80%. Outros achados menos comuns foram aumento do calibre dos vasos, consolidações e nódulos do espaço aéreo. CONCLUSÃO: O padrão predominante encontrado nos pacientes estudados foi o de opacidades em vidro fosco associadas a espessamento dos septos interlobulares (padrão de pavimentação em mosaico, com derrame pleural bilateral, predominante à direita.OBJECTIVE: This study aimed to use high-resolution computed tomography scans of the chest to characterize the principal alterations occurring in cases of hydrostatic pulmonary edema. METHODS: A retrospective analysis was made of the tomography scans of 15 patients presenting clinical profiles of hydrostatic pulmonary edema. The cases were divided into five groups by etiology: congestive heart failure (n = 7; acute mitral valve disease (n = 2; acute myocardial infarction (n = 2; myocarditis (n = 2; and fibrosing mediastinitis (n = 2. RESULTS: The principal findings in the cases of hydrostatic pulmonary edema were ground-glass opacities (in 100%, interlobular septal thickening (in 100%, pleural effusion (in 87% and peribronchovascular interstitial thickening (in 80%. Other, less common

  19. Validation of computed tomography protocols for simulated mandibular lesions: a comparison study Validação de protocolos de tomografia computadorizada para lesões simuladas em mandíbula: estudo comparativo

    Directory of Open Access Journals (Sweden)

    Andréia Perrella

    2007-06-01

    Full Text Available Computed tomography is the choice technique to assess oral and maxillofacial osseous lesions because it provides hard and soft tissues visualization in one examination without superimposition of surrounding structures. This examination offers a significant advance in maxillofacial lesions detection with an excellent anatomic resolution. The aim of this research was to evaluate the validity of two protocols, in axial sections, in simulated mandibular lesions. Two CT protocols were obtained in dry mandibles in which perforations were done simulating lesions. Two observers, previously calibrated, evaluated the images according to different parameters. The results indicated that the sensitivity and specificity in lesion detection were 100% for both protocols, but the detection of loci number of multilocular lesions and the location and detection of medullar invasion obtained reduced validity values, which were influenced by the acquisition protocol. We concluded that thinner axial slices and reconstructions were more effective in detecting early medullar invasion and loci number. Thicker protocols were not considered appropriate to detect multilocular lesions and early stages of medullar invasion.A tomografia Computadorizada é a técnica de escolha no exame de lesões ósseas orais e maxilo-faciais porque proporciona a visualização de tecidos duros e moles em aquisição única e sem sobreposição de estruturas adjacentes. Este exame oferece um avanço significativo na detecção de lesões maxilo-faciais, com excelente resolução anatômica. O objetivo desta pesquisa foi avaliar a validade de dois protocolos, em secções axiais, em lesões simuladas de mandíbula. Dois protocolos de TC foram obtidos em mandíbulas secas em que foram feitas perfurações, simulando lesões. Dois observadores previamente calibrados avaliaram as imagens seguindo parâmetros diversos. Como resultados pudemos observar que a sensibilidade e a especificidade foram

  20. Axial weak currents in the Wess-Zumino term

    International Nuclear Information System (INIS)

    Fujikawa, Kazuo.

    1985-03-01

    The conventional axial gauging of the Wess-Zumino term leads to the results which do not necessarily agree with the expectations on the basis of quark level Ward-Takahashi identities. This discrepancy arises from the fact that the quark level anomalous identities reflect the short distance structure of QCD, whereas the gauging of the Wess-Zumino term reflects the axial symmetry in the spontaneously broken chiral phase. The low energy theorem for axial weak fields is not sharply defined, in contrast to the case of vector fields where no such complications arise. (author)

  1. Magmatic controls on axial relief and faulting at mid-ocean ridges

    Science.gov (United States)

    Liu, Zhonglan; Buck, W. Roger

    2018-06-01

    Previous models do not simultaneously reproduce the observed range of axial relief and fault patterns at plate spreading centers. We suggest that this failure is due to the approximation that magmatic dikes open continuously rather than in discrete events. During short - lived events, dikes open not only in the strong axial lithosphere but also some distance into the underlying weaker asthenosphere. Axial valley relief affects the partitioning of magma between the lithosphere and asthenosphere during diking events. The deeper the valley, the more magma goes into lithospheric dikes in each event and so the greater the average opening rate of those dikes. The long-term rate of lithospheric dike opening controls faulting rate and axial depth. The feedback between axial valley depth D and lithospheric dike opening rate allows us to analytically relate steady-state values of D to lithospheric thickness HL and crustal thickness HC. A two-dimensional model numerical model with a fixed axial lithospheric structure illustrates the analytic model implications for axial faulting. The predictions of this new model are broadly consistent with global and segment-scale trends of axial depth and fault patterns with HL and HC.

  2. Radial loads and axial thrusts on centrifugal pumps

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    The proceedings of a seminar organised by the Power Industries Division of the IMechE are presented in this text. Complete contents: Review of parameters influencing hydraulic forces on centrifugal impellers; The effect of fluid forces at various operation conditions on the vibrations of vertical turbine pumps; A review of the pump rotor axial equilibrium problem - some case studies; Dynamic hydraulic loading on a centrifugal pump impeller; Experimental research on axial thrust loads of double suction centrifugal pumps; A comparison of pressure distribution and radial loads on centrifugal pumps; A theoretical and experimental investigation of axial thrusts within a multi-stage centrifugal pump

  3. The effects of initial rise and axial loads on MEMS arches

    KAUST Repository

    Tella, Sherif Adekunle

    2017-04-07

    Arch microbeams have been utilized and proposed for many uses over the past few years due to their large tunability and bistability. However, recent experimental data have shown different mechanical behavior of arches when subjected to axial loads. This paper aims to investigate in depth the influence of the competing effects of initial rise and axial loads on the mechanical behavior of micromachined arches; mainly their static deflection and resonant frequencies. Based on analytical solutions, the static response and eigenvalue problems are analyzed for various values of initial rises and axial loads. Universal curves showing the variation of the first three resonance frequencies of the arch are generated for various values of initial rise under both tensile and compressive axial loads. This study shows that increasing the tensile or compressive axial loads for different values of initial rise may lead to either increase in the stiffness of the beam or initial decrease in the stiffness, which later increases as the axial load is increased depending on the dominant effect of the initial rise of the arch and the axial load. The obtained universal curves represent useful design tools to predict the tunability of arches under axial loads for various values of initial rises. The use of the universal curves is demonstrated with an experimental case study. Analytical formulation is developed to predict the point of minimum where the trend of the resonance frequency versus axial loads changes qualitatively due to the competing effects of axial loads and initial curvature.

  4. Quasi-renormalization of the axial vector model

    International Nuclear Information System (INIS)

    Schweda, M.

    1979-01-01

    Using the regulator-free BPHZL renormalization scheme the problem of anomalies in a massive axial vector meson model is reinvestigated. The Adler-Bardeen-Bell-Jackiw anomaly introduces some impressive modifications: the nontrivial self-energy and the counterterm of the longitudinal part of the axial vector field depend on the anomaly via the anomalous Ward identity. The investigations are based on a Fermi-type gauge. (author)

  5. Effect of axial heat flux distribution on CHF

    Energy Technology Data Exchange (ETDEWEB)

    Park, Cheol

    2000-10-01

    Previous investigations for the effect of axial heat flux distributions on CHF and the prediction methods are reviewed and summarized. A total of 856 CHF data in a tube with a non-uniform axial heat flux distribution has been compiled from the articles and analyzed using the 1995 Groeneveld look-up table. The results showed that two representative correction factors, K5 of the look-up table and Tongs F factor, can be applied to describe the axial heat flux distribution effect on CHF. However, they overpredict slightly the measured CHF, depending on the quality and flux peak shape. Hence, a corrected K5 factor, which accounts for the axial heat flux distribution effect is suggested to correct these trends. It predicted the CHF power for the compiled data with an average error of 1.5% and a standard deviation of 10.3%, and also provides a reasonable prediction of CHF locations.

  6. Continuous millennial decrease of the Earth's magnetic axial dipole

    Science.gov (United States)

    Poletti, Wilbor; Biggin, Andrew J.; Trindade, Ricardo I. F.; Hartmann, Gelvam A.; Terra-Nova, Filipe

    2018-01-01

    Since the establishment of direct estimations of the Earth's magnetic field intensity in the first half of the nineteenth century, a continuous decay of the axial dipole component has been observed and variously speculated to be linked to an imminent reversal of the geomagnetic field. Furthermore, indirect estimations from anthropologically made materials and volcanic derivatives suggest that this decrease began significantly earlier than direct measurements have been available. Here, we carefully reassess the available archaeointensity dataset for the last two millennia, and show a good correspondence between direct (observatory/satellite) and indirect (archaeomagnetic) estimates of the axial dipole moment creating, in effect, a proxy to expand our analysis back in time. Our results suggest a continuous linear decay as the most parsimonious long-term description of the axial dipole variation for the last millennium. We thus suggest that a break in the symmetry of axial dipole moment advective sources occurred approximately 1100 years earlier than previously described. In addition, based on the observed dipole secular variation timescale, we speculate that the weakening of the axial dipole may end soon.

  7. Dechanneling function for relativistic axially channeled electrons

    International Nuclear Information System (INIS)

    Muralev, V.A.; Telegin, V.I.

    1981-01-01

    Behaviour of the x(t) dechanneling function depending on the depth is theoretically studied. Theoretical consideration of x(t) for axial channeled relativistic electrons in anisotropic medium results in two-dimensional kinetic equation with mixed derivatives of the parabolic type. The kinetic equation in the approximation of the continuous Lindchard model for relativistic axial channeled electrons is numerically solved. The depth dependence of the x(t) dechanneling function is obtained [ru

  8. Singlet axial constant from QCD sum rules

    International Nuclear Information System (INIS)

    Belitskij, A.V.; Teryaev, O.V.

    1995-01-01

    We analyze the singlet axial form factor of the proton for small momentum transferred in the framework of QCD sum rules using the interpolating nucleon current which explicitly accounts for the gluonic degrees of freedom. As the result we come to the quantitative prediction of the singlet axial constant. It is shown that the bilocal power corrections play the most important role in the analysis. 21 refs., 3 figs

  9. Axial clamp for nuclear reactor head penetration conoseal joints

    International Nuclear Information System (INIS)

    Hackley, T.A.

    1986-01-01

    A method for forming a sealed coupling between two bodies each body presenting an abutment surface, the bodies being arranged so that their respective abutment surfaces are axially adjacent one another and define a space therebetween in which a deformable gasket is disposed. An axial external force is applied to the bodies for compressing the abutment surfaces together against the gasket to form a seal between the bodies and the bodies are immobilized relative to one another while the external force is being applied to the bodies so that sufficient compression will be maintained by the abutment surfaces to preserve the integrity of the seal when the external axial force is withdrawn. The external axial force is then withdrawn, leaving the two bodies coupled together via the seal. (author)

  10. Axial Dispersion during Hanford Saltcake Washing

    International Nuclear Information System (INIS)

    Josephson, Gary B.; Geeting, John GH; Lessor, Delbert L.; Barton, William B.

    2006-01-01

    Clean up of Hanford salt cake wastes begins with dissolution retrieval of the sodium rich salts that make up the dominant majority of mass in the tanks. Water moving through the porous salt cake dissolves the soluble components and also displaces the soluble radionuclides (e.g. 137Cs and 99TcO4- ). The separation that occurs from this displacement, known as Selective dissolution, is an important component in Hanford?s pretreatment of low activity wastes for subsequent Supplemental treatment. This paper describes lab scale testing conducted to evaluate Selective dissolution of cesium from non-radioactive Hanford tank 241-S-112 salt cake simulant containing the primary chemicals found the actual tank. An modified axial dispersion model with increasing axial dispersion was developed to predict cesium removal. The model recognizes that water dissolves the salt cake during washing, which causes an increase in the axial dispersion during the wash. This model was subsequently compared with on-line cesium measurements from the retrieval of tank 241-S-112. The model had remarkably good agreement with both the lab scale and full scale data

  11. [Myopia: frequency of lattice degeneration and axial length].

    Science.gov (United States)

    Martín Sánchez, M D; Roldán Pallarés, M

    2001-05-01

    To evaluate the relationship between lattice retinal degeneration and axial length of the eye in different grades of myopia. A sample of 200 eyes from 124 myopic patients was collected by chance. The average age was 34.8 years (20-50 years) and the myopia was between 0.5 and 20 diopters (D). The eyes were grouped according to the degree of refraction defect, the mean axial length of each group (Scan A) and the frequency of lattice retinal degeneration and the relationship between these variables was studied. The possible influence of age on our results was also considered. For the statistical analysis, the SAS 6.07 program with the variance analysis for quantitative variables, and chi(2) test for qualitative variables with a 5% significance were used. A multivariable linear regression model was also adjusted. The highest frequency of lattice retinal degeneration occurred in those myopia patients having more than 15 D, and also in the group of myopia patients between 3 and 6 D, but this did not show statistical significance when compared with the other myopic groups. If the axial length is assessed, a greater frequency of lattice retinal degeneration is also found when the axial length is 25-27 mm and 29-30 mm, which correspond, respectively, to myopias between 3-10 D and more than 15 D. When the multivariable linear regression model was adjusted, the axial length showed the existence of lattice retinal degeneration (beta 0.41 mm; p=0.08) adjusted by the number of diopters (beta 0.38 mm; plattice retinal degeneration was found for myopias with axial eye length between 29-30 mm (more than 15 D), and 25-27 mm (between 3-10 D).

  12. Investigation of angular and axial smoothing of PET data

    International Nuclear Information System (INIS)

    Daube-Witherspoon, M.E.; Carson, R.E.

    1996-01-01

    Radial filtering of emission and transmission data is routinely performed in PET during reconstruction in order to reduce image noise. Angular smoothing is not typically done, due to the introduction of a non-uniform resolution loss; axial filtering is also not usually performed on data acquired in 2D mode. The goal of this paper was to assess the effects of angular and axial smoothing on noise and resolution. Angular and axial smoothing was incorporated into the reconstruction process on the Scanditronix PC2048-15B brain PET scanner. In-plane spatial resolution and noise reduction were measured for different amounts of radial and angular smoothing. For radial positions away from the center of the scanner, noise reduction and degraded tangential resolution with no loss of radial resolution were seen. Near the center, no resolution loss was observed, but there was also no reduction in noise for angular filters up to a 7 degrees FWHM. These results can be understood by considering the combined effects of smoothing projections across rows (angles) and then summing (backprojecting). Thus, angular smoothing is not optimal due to its anisotropic noise reduction and resolution degradation properties. However, uniform noise reduction comparable to that seen with radial filtering can be achieved with axial smoothing of transmission data. The axial results suggest that combined radial and axial transmission smoothing could lead to improved noise characteristics with more isotropic resolution degradation

  13. Axial clamp for nuclear reactor head penetration conoseal joints

    International Nuclear Information System (INIS)

    Hackley, T.A.

    1987-01-01

    A method is described for forming a sealed coupling between two bodies, each body presenting an annular abutment surface. The respective bodies are arranged so that their respective annular abutment surfaces are axially adjacent one another, defining a space therebetween, wherein a deformable gasket is disposed within the space. The method comprises: providing one of the bodies with an annular projection; providing the other body with threads for receiving an annular locknut which can be tightened to bear against the annular projection of the one body; applying an external axial forced to the bodies for compressing the abutment surfaces together against the gasket to form a seal between the bodies; immobilizing the bodies relative to one another while the external force is being applied to the bodies by hand-tightening an annular locknut via the threads of the other body until the locknut abuts the annular projection of the one body, substantially preventing relative axial movement between the bodies when the external axial force is withdrawn; and withdrawing the external axial force applied to the bodies, leaving the two bodies coupled together via the seal

  14. Three-dimensional magnetotelluric axial anisotropic forward modeling and inversion

    Science.gov (United States)

    Cao, Hui; Wang, Kunpeng; Wang, Tao; Hua, Boguang

    2018-06-01

    Magnetotelluric (MT) data has been widely used to image underground electrical structural. However, when the significant axial resistivity anisotropy presents, how this influences three-dimensional MT data has not been resolved clearly yet. We here propose a scheme for three-dimensional modeling of MT data in presence of axial anisotropic resistivity, where the electromagnetic fields are decomposed into primary and secondary components. A 3D staggered-grid finite difference method is then used to resolve the resulting 3D governing equations. Numerical tests have completed to validate the correctness and accuracy of the present algorithm. A limited-memory Broyden-Fletcher-Goldfarb-Shanno method is then utilized to realize the 3D MT axial anisotropic inversion. The testing results show that, compared to the results of isotropic resistivity inversion, taking account the axial anisotropy can much improve the inverted results.

  15. Ball Screw Actuator Including an Axial Soft Stop

    Science.gov (United States)

    Wingett, Paul T. (Inventor); Forrest, Steven Talbert (Inventor); Abel, Steve (Inventor); Woessner, George (Inventor); Hanlon, Casey (Inventor)

    2016-01-01

    An actuator includes an actuator housing, a ball screw, and an axial soft stop assembly. The ball screw extends through the actuator housing and has a first end and a second end. The ball screw is coupled to receive a drive force and is configured, upon receipt of the drive force, to selectively move in a retract direction and an extend direction. The axial soft stop assembly is disposed within the actuator housing. The axial soft stop assembly is configured to be selectively engaged by the ball screw and, upon being engaged thereby, to translate, with compliance, a predetermined distance in the extend direction, and to prevent further movement of the ball screw upon translating the predetermined distance.

  16. Axial Vircator for Electronic Warfare Applications

    Directory of Open Access Journals (Sweden)

    L. Drazan

    2009-12-01

    Full Text Available This paper deals with a high power microwave generator with virtual cathode – vircator in axial release for electronic warfare applications. The classification of directed energy weapons microwave (DEWM is introduced together with basic block diagrams of a particular class of DEWM. In the paper, methods for designing vircator pulsed power supply, axial vircator structure, measurement methods and experimental results are presented. The vircator in electromagnetic ammunition is powered by magneto-cumulative generator and in weapons for defense of objects (WDO, it is powered by Marx generator. The possible applications of a vircator in the DEWM area are discussed.

  17. Generalized dynamic model and control of ambiguous mono axial vehicle robot

    Directory of Open Access Journals (Sweden)

    Frantisek Duchon

    2016-09-01

    Full Text Available This article deals with the novel concept of ambiguous mono axial vehicle robot. Such robot is a combination of Segway and dicycle, which utilizes the advantages of each chassis. The advantage of dicycle is lower energy consumption during the movement and the higher safety of carried payload. The movable platform inside the ambiguous mono axial vehicle allows using the various sensors or devices. This will change the ambiguous mono axial vehicle to the Segway type robot. Both these modes are necessary to control in the stable mode to ensure the safety of the ambiguous mono axial vehicle’s movement. The main contents of the article contain description of generalized dynamic model of ambiguous mono axial vehicle and related control of ambiguous mono axial vehicle. The proposal is unique in that the same controller is used for both modes. Several simulations verify proposed control schemes and identified parameters. Moreover, the dicycle type of platform has never been used in robotics and that is another novelty.

  18. Measurement for cobalt target activity and its axial distribution

    International Nuclear Information System (INIS)

    Li Xingyuan; Chen Zigen.

    1985-01-01

    Cobalt target activity and its axial distribution are measured in process of producing radioactive isotopes 60 Co by irradiation in HFETR. Cobalt target activity is obtained with measured data at 3.60 m and 4.60 m, relative axial distribution of cobalt target activity is obtained with one at 30 cm, and axial distribution of cobalt target activity(or specific activity) is obtained with both of data. The difference between this specific activity and measured result for 60 Co teletherapy sources in the end is less than +- 5%

  19. The spin of the proton and the axial anomaly

    International Nuclear Information System (INIS)

    Hatsuda, T.; Zahed, I.

    1989-01-01

    We show that a consistent treatment of the abelian axial anomaly in a two-phase model of the proton yields a flavor singlet axial current that is saturated by the anomaly at Q 2 =0 in the chiral limit. This result suggests that at Q 2 =0 the matrix element of the flavor singlet axial current in a polarized proton state is small while the proton spin is still one-half. Modulo the QCD evolution equation, this result is in fair agreement with the recent EMC data. (orig.)

  20. Axial to transverse energy mixing dynamics in octupole-based magnetostatic antihydrogen traps

    Science.gov (United States)

    Zhong, M.; Fajans, J.; Zukor, A. F.

    2018-05-01

    The nature of the trajectories of antihydrogen atoms confined in an octupole minimum-B trap is of great importance for upcoming spectroscopy, cooling, and gravity experiments. Of particular interest is the mixing time between the axial and transverse energies for the antiatoms. Here, using computer simulations, we establish that almost all trajectories are chaotic, and then quantify the characteristic mixing time between the axial and transverse energies. We find that there are two classes of trajectories: for trajectories whose axial energy is higher than about 20% of the total energy, the axial energy substantially mixes within about 10 s, whereas for trajectories whose axial energy is lower than about 10% of the total energy, the axial energy remains nearly constant for 1000 s or longer.

  1. Test Setup for Axially Loaded Piles in Sand

    DEFF Research Database (Denmark)

    Thomassen, Kristina

    The test setup for testing axially static and cyclic loaded piles in sand is described in the following. The purpose for the tests is to examine the tensile capacity of axially loaded piles in dense fully saturated sand. The pile dimensions are chosen to resemble full scale dimension of piles used...... in offshore pile foundations today....

  2. Computerized tomography findings in Fahr's syndrome Achados da tomografia computadorizada na síndrome de Fahr

    Directory of Open Access Journals (Sweden)

    Andréia V. Faria

    2004-09-01

    Full Text Available We analyzed computerized tomography (CT findings in six patients with Fahr's syndrome. They presented calcifications in basal ganglia, dentate nucleus, subcortical region and semioval center, due to alteration in calcium metabolism or due to senile relative hypoxemic state. The image pattern was not strictly related with etiology, although some differences in dystrophic senile calcifications (the only one present in semioval center and absent in subcortical region. CT is an easy exam, has maximum sensitivity and allows diagnosis, contributing to early treatment of many etiologies of Fahr's syndrome.Analisamos os achados de tomografia computadorizada (TC de seis pacientes com síndrome de Fahr. Eles apresentaram calcificações nos gânglios da base, núcleo denteado, região subcortical e centro semi-oval, devidas a distúrbios no metabolismo do cálcio ou a estado de hipóxia relativa, por senilidade. O padrão de imagem não apresenta relação clara com a etiologia, apesar de algumas diferenças no caso das calcificações distróficas senis (as únicas presentes nos centros semi-ovais e ausentes na região subcortical. TC é um exame de fácil realização, máxima sensibilidade e permite o diagnóstico, contribuindo para o tratamento precoce de muitas das etiologias da síndrome de Fahr.

  3. An axial calculation method for accurate two-dimensional PWR core simulation

    International Nuclear Information System (INIS)

    Grimm, P.

    1985-02-01

    An axial calculation method, which improves the agreement of the multiplication factors determined by two- and three-dimensional PWR neutronic calculations, is presented. The axial buckling is determined at each time point so as to reproduce the increase of the leakage due to the flattening of the axial power distribution and the effect of the axial variation of the group constants of the fuel on the reactivity is taken into account. The results of a test example show that the differences of k-eff and cycle length between two- and three-dimensional calculations, which are unsatisfactorily large if a constant buckling is used, become negligible if the results of the axial calculation are used in the two-dimensional core simulation. (Auth.)

  4. Reactive control of subsonic axial fan noise in a duct.

    Science.gov (United States)

    Liu, Y; Choy, Y S; Huang, L; Cheng, L

    2014-10-01

    Suppressing the ducted fan noise at low frequencies without varying the flow capacity is still a technical challenge. This study examines a conceived device consisting of two tensioned membranes backed with cavities housing the axial fan for suppression of the sound radiation from the axial fan directly. The noise suppression is achieved by destructive interference between the sound fields from the axial fan of a dipole nature and sound radiation from the membrane via vibroacoustics coupling. A two-dimensional model with the flow effect is presented which allows the performance of the device to be explored analytically. The air flow influences the symmetrical behavior and excites the odd in vacuo mode response of the membrane due to kinematic coupling. Such an asymmetrical effect can be compromised with off-center alignment of the axial fan. Tension plays an important role to sustain the performance to revoke the deformation of the membrane during the axial fan operation. With the design of four appropriately tensioned membranes covered by a cylindrical cavity, the first and second blade passage frequencies of the axial fan can be reduced by at least 20 dB. The satisfactory agreement between experiment and theory demonstrates that its feasibility is practical.

  5. Equation of motion for the axial gravitational superfield

    International Nuclear Information System (INIS)

    Ogievetsky, V.; Sokatchev, E.

    1980-01-01

    Transformation properties of the axial supergravitational field variants are investigated. The equation of motion for the axial gravitational superfield is derived by direct variation of the N = 1 supergravity action. The left-hand side of this equation is a component of the torsion tensor, and the right-hand side is the supercurrent. The question about the cosmological term in supergravity is discussed

  6. Development of vortex model with realistic axial velocity distribution

    International Nuclear Information System (INIS)

    Ito, Kei; Ezure, Toshiki; Ohshima, Hiroyuki

    2014-01-01

    A vortex is considered as one of significant phenomena which may cause gas entrainment (GE) and/or vortex cavitation in sodium-cooled fast reactors. In our past studies, the vortex is assumed to be approximated by the well-known Burgers vortex model. However, the Burgers vortex model has a simple but unreal assumption that the axial velocity component is horizontally constant, while in real the free surface vortex has the axial velocity distribution which shows large gradient in radial direction near the vortex center. In this study, a new vortex model with realistic axial velocity distribution is proposed. This model is derived from the steady axisymmetric Navier-Stokes equation as well as the Burgers vortex model, but the realistic axial velocity distribution in radial direction is considered, which is defined to be zero at the vortex center and to approach asymptotically to zero at infinity. As the verification, the new vortex model is applied to the evaluation of a simple vortex experiment, and shows good agreements with the experimental data in terms of the circumferential velocity distribution and the free surface shape. In addition, it is confirmed that the Burgers vortex model fails to calculate accurate velocity distribution with the assumption of uniform axial velocity. However, the calculation accuracy of the Burgers vortex model can be enhanced close to that of the new vortex model in consideration of the effective axial velocity which is calculated as the average value only in the vicinity of the vortex center. (author)

  7. The deep structure of Axial Volcano

    Science.gov (United States)

    West, Michael Edwin

    The subsurface structure of Axial Volcano, near the intersection of the Juan de Fuca Ridge and the Cobb-Eickelberg seamount chain in the northeast Pacific, is imaged from an active source seismic experiment. At a depth of 2.25 to 3.5 km beneath Axial lies an 8 km x 12 km region of very low seismic velocities that can only be explained by the presence of magma. In the center of this magma storage chamber at 2--3.5 km below sea floor, the crust is at least 10--20% melt. At depths of 4--5 km there is evidence of additional low concentrations of magma (a few percent) over a larger area. In total, 5--11 km3 of magma are stored in the mid-crust beneath Axial. This is more melt than has been positively identified under any basaltic volcano on Earth. It is also far more than the 0.1--0.2 km3 emplaced during the 1998 eruption. The implied residence time in the magma reservoir of a few hundred to a few thousand years agrees with geochemical trends which suggest prolonged storage and mixing of magmas. The large volume of melt bolsters previous observations that Axial provides much of the material to create crust along its 50 km rift zones. A high velocity ring-shaped feature sits above the magma chamber just outside the caldera walls. This feature is believed to be the result of repeated dike injections from the magma body to the surface during the construction of the volcanic edifice. A rapid change in crustal thickness from 8 to 11 km within 15 km of the caldera implies focused delivery of melt from the mantle. The high flux of magma suggests that melting occurs deeper in the mantle than along the nearby ridge. Melt supply to the volcano is not connected to any plumbing system associated with the adjacent segments of the Juan de Fuca Ridge. This suggests that, despite Axial's proximity to the ridge, the Cobb hot spot currently drives the supply of melt to the volcano.

  8. Anisotropic yield surfaces in bi-axial cyclic plasticity

    International Nuclear Information System (INIS)

    Rider, R.J.; Harvey, S.J.; Breckell, T.H.

    1985-01-01

    Some aspects of the behaviour of yield surfaces and work-hardening surfaces occurring in biaxial cyclic plasticity have been studied experimentally and theoretically. The experimental work consisted of subjecting thin-walled tubular steel specimens to cyclic plastic torsion in the presence of sustained axial loads of various magnitudes. The experimental results show that considerable anisotropy is induced when the cyclic shear strains are dominant. Although the true shapes of yield and work-hardening surfaces can be very complex, a mathematical model is presented which includes both anisotropy and Bauschinger effects. The model is able to qualitatively predict the deformation patterns during a cycle of applied plastic shear strain for a range of sustained axial stresses and also indicate the material response to changes in axial stress. (orig.)

  9. Light-front view of the axial anomaly

    International Nuclear Information System (INIS)

    Ji, C.; Rey, S.

    1996-01-01

    Motivated by an apparent puzzle of the light-front vacua incompatible with the axial anomaly, we have considered the two-dimensional massless Schwinger model for an arbitrary interpolating angle of Hornbostel close-quote s interpolating quantization surface. By examining spectral deformation of the Dirac sea under an external electric field semiclassically, we have found that the axial anomaly is quantization angle independent. This indicates an intricate nontrivial vacuum structure present even in the light-front limit. copyright 1996 The American Physical Society

  10. Gravitational waves from the axial perturbations of hyperon stars

    International Nuclear Information System (INIS)

    Wen De-Hua; Yan Jing; Liu Xue-Mei

    2012-01-01

    The eigen-frequencies of the axial w-mode oscillations of hyperon stars are examined. It is shown that as the appearance of hyperons softens the equation of state of the super-density matter, the frequency of gravitational waves from the axial w-mode of hyperon star becomes smaller than that of a traditional neutron star at the same stellar mass. Moreover, the eigenfrequencies of hyperon stars also have scaling universality. It is shown that the EURO third-generation gravitational-wave detector has the potential to detect the gravitational-wave signal emitted from the axial w-mode oscillations of a hyperon star. (general)

  11. Axial injection in Orsay superconducting cyclotron

    International Nuclear Information System (INIS)

    Depauw, J.; Kugler, M.F.; Legoff, A.; Potier, J.C.; Richomme, A.; Skowron, R.; Mandrillon, P.; Schapira, J.P.

    1983-01-01

    The compact superconducting cyclotron currently planned at IPN at Orsay is designed for light ion acceleration together with heavy ion acceleration. From the beginning, for this reason, a central geometry able to receive an inflector (to 90deg C) allowing the axial injection of low energy ion beams given by an outer source. The present study is aimed at showing the technical feasibility of theoretical results obtained on axial injection. First experimental study has been made of spatial repartition in three dimensions of electric potential developed by a central geometry of 3 electrodes. Then, the electric study of an electrostatic mirror has been made [fr

  12. Bessel beam CARS of axially structured samples

    Science.gov (United States)

    Heuke, Sandro; Zheng, Juanjuan; Akimov, Denis; Heintzmann, Rainer; Schmitt, Michael; Popp, Jürgen

    2015-06-01

    We report about a Bessel beam CARS approach for axial profiling of multi-layer structures. This study presents an experimental implementation for the generation of CARS by Bessel beam excitation using only passive optical elements. Furthermore, an analytical expression is provided describing the generated anti-Stokes field by a homogeneous sample. Based on the concept of coherent transfer functions, the underling resolving power of axially structured geometries is investigated. It is found that through the non-linearity of the CARS process in combination with the folded illumination geometry continuous phase-matching is achieved starting from homogeneous samples up to spatial sample frequencies at twice of the pumping electric field wave. The experimental and analytical findings are modeled by the implementation of the Debye Integral and scalar Green function approach. Finally, the goal of reconstructing an axially layered sample is demonstrated on the basis of the numerically simulated modulus and phase of the anti-Stokes far-field radiation pattern.

  13. Uniform Decay for Solutions of an Axially Moving Viscoelastic Beam

    Energy Technology Data Exchange (ETDEWEB)

    Kelleche, Abdelkarim, E-mail: kellecheabdelkarim@gmail.com [Université des Sciences et de la Technologie Houari Boumediene, Faculté des Mathématiques (Algeria); Tatar, Nasser-eddine, E-mail: tatarn@Kfupm.edu.sa [King Fahd University of Petroleum and Minerals, Department of Mathematics and Statistics (Saudi Arabia)

    2017-06-15

    The paper deals with an axially moving viscoelastic structure modeled as an Euler–Bernoulli beam. The aim is to suppress the transversal displacement (transversal vibrations) that occur during the axial motion of the beam. It is assumed that the beam is moving with a constant axial speed and it is subject to a nonlinear force at the right boundary. We prove that when the axial speed of the beam is smaller than a critical value, the dissipation produced by the viscoelastic material is sufficient to suppress the transversal vibrations. It is shown that the rate of decay of the energy depends on the kernel which arise in the viscoelastic term. We consider a general kernel and notice that solutions cannot decay faster than the kernel.

  14. Atlanto-axial Subluxation in rheumatoid arthritis: description of a case

    International Nuclear Information System (INIS)

    Medina, Yimy F; Martinez V, Jose B; Restrepo, Jose Felix; Rondon H, Federico; Iglesias G, Antonio

    2004-01-01

    The damage of the spine by rheumatoid arthritis is multiple and a variety of affectations have been described at cervical level, being the anterior atlanto-axial subluxation and vertical subluxation the more common. However the posterior atlanto-axial subluxation has been rarely described. In this paper, we describe the case of a patient with posterior atlanto-axial subluxaction in addition to its infrequent manifestation of alteration of the lower cranial nerves as a manifestation of myelopathy

  15. Analysis of axial compressive loaded beam under random support excitations

    Science.gov (United States)

    Xiao, Wensheng; Wang, Fengde; Liu, Jian

    2017-12-01

    An analytical procedure to investigate the response spectrum of a uniform Bernoulli-Euler beam with axial compressive load subjected to random support excitations is implemented based on the Mindlin-Goodman method and the mode superposition method in the frequency domain. The random response spectrum of the simply supported beam subjected to white noise excitation and to Pierson-Moskowitz spectrum excitation is investigated, and the characteristics of the response spectrum are further explored. Moreover, the effect of axial compressive load is studied and a method to determine the axial load is proposed. The research results show that the response spectrum mainly consists of the beam's additional displacement response spectrum when the excitation is white noise; however, the quasi-static displacement response spectrum is the main component when the excitation is the Pierson-Moskowitz spectrum. Under white noise excitation, the amplitude of the power spectral density function decreased as the axial compressive load increased, while the frequency band of the vibration response spectrum increased with the increase of axial compressive load.

  16. SCLERAL AND CHOROIDAL THICKNESS IN SECONDARY HIGH AXIAL MYOPIA.

    Science.gov (United States)

    Shen, Ling; You, Qi Sheng; Xu, Xiaolin; Gao, Fei; Zhang, Zhibao; Li, Bin; Jonas, Jost B

    2016-08-01

    To assess differences in scleral and choroidal thickness between eyes with secondary high axial myopia caused by congenital glaucoma, eyes with primary high axial myopia, and nonhighly myopic eyes. The study consisted of 301 Chinese individuals with a mean age of 23.9 ± 22.6 years and mean axial length of 24.8 ± 4.2 mm. It included the "secondary highly myopic group" (SHMG) because of congenital glaucoma (n = 20 eyes; axial length >26.0 mm), the "primary highly myopic group" (PHMG) (n = 73; axial length >26.0 mm), and the remaining nonhighly myopic group (NHMG). The secondary highly myopic group versus the primary highly myopic group had significantly thinner sclera in the pars plana region (343 ± 71 μm versus 398 ± 83 μm; P = 0.006), whereas scleral thickness in other regions did not differ significantly between both highly myopic groups and was significantly thinner in both highly myopic groups than in the NHMG. Mean total scleral volume did not differ significantly (P > 0.20) between any group (SHMG: 659 ± 106 μm; PHMG: 667 ± 128 μm; NHMG: 626 ± 135 μm). Choroidal thickness was significantly thinner in both highly myopic groups than in the NHMG, with no significant differences between both highly myopic groups. Choroidal volume did not differ significantly (P > 0.40) between any of the groups (SHMG: 43 ± 12 μm; PHMG: 43 ± 13 μm; NHMG: 46 ± 17 μm). In secondary high axial myopia, the sclera gets thinner anterior and posterior to the equator; whereas in primary high axial myopia, scleral thinning is predominantly found posterior to the equator. Because volume of sclera and choroid did not differ between any group, scleral and choroidal thinning in myopia may be due to a rearrangement of tissue and not due to the new formation of tissue.

  17. CT findings after normal and unsuccessful functional endoscopic sinus surgery; Ruolod della tomografia computerizzata dopo chirurgia funzionale dei seni paranasali: rilievi normali e valutazioni degli insuccessi chirurgici

    Energy Technology Data Exchange (ETDEWEB)

    Scribano, E.; Ascenti, G.; Bellinvia, A.; Mazziotti, S.; Lamberto, S. [Messina Univ., Messina (Italy). Ist. di Scienze Radiologiche; Cascio, F. [Messina Univ., Messina (Italy). Ist. di Otorinolaringoiatria

    1999-09-01

    The paper investigates the functional endoscopic sinus surgery with the Messer-linger's technique which treats benign or inflammatory diseases of paranasal sinuses resistant to medical therapy. The goal of this type of surgery is to open the obstructed sinus ostia and restore normal aeration and mucociliary clearance. The computerized tomography permits an accurate assessment of extension and results of functional endoscopic sinus surgery. [Italian] L'articolo discute l'uso della tecnica di Messerklinger nella chirurgia funzionale endoscopica dei seni paranasali per il trattamento delle malattie benigne e delle infiammazioni croniche. Essa disostruisce gli osti sinusali ripristinando la normale areazione e la pulizia mucociliare. La tomografia computerizzata consente di valutare l'estensione e i risultati del trattamento chirurgico funzionale, soprattutto nel caso di insuccesso terapeutico, rilevando malattia nasosinusale ricorrente e-o recidiva.

  18. Plasma sheath axial phase dynamics in coaxial device

    Energy Technology Data Exchange (ETDEWEB)

    Soliman, H.M. (Plasma Physics Dept., NRC, Atomic Energy Authority, Cairo (Egypt)); Masoud, M.M. (Plasma Physics Dept., NRC, Atomic Energy Authority, Cairo (Egypt))

    1994-10-01

    The study of the plasma sheath dynamics in the axial phase has been carried out in a 3 kJ coaxial system of Mather type for two different inner electrode (IE) lengths, 20 cm and 31.5 cm. For both lengths, measurements showed that the plasma sheath is splitted into two layers at the breech, which is referred to as a shock front and its magnetic piston. It has been found that the two layers of the plasma current sheath rotate around the inner electrode. At the muzzle the back layer reverse its rotation direction due to the magnetic field structure of the system. Results showed that the axial velocity of the first layer is greater than the second one all over the axial phase within the range between 1.4 and 1.7. (orig.).

  19. Plasma sheath axial phase dynamics in coaxial device

    International Nuclear Information System (INIS)

    Soliman, H.M.; Masoud, M.M.

    1994-01-01

    The study of the plasma sheath dynamics in the axial phase has been carried out in a 3 kJ coaxial system of Mather type for two different inner electrode (IE) lengths, 20 cm and 31.5 cm. For both lengths, measurements showed that the plasma sheath is splitted into two layers at the breech, which is referred to as a shock front and its magnetic piston. It has been found that the two layers of the plasma current sheath rotate around the inner electrode. At the muzzle the back layer reverse its rotation direction due to the magnetic field structure of the system. Results showed that the axial velocity of the first layer is greater than the second one all over the axial phase within the range between 1.4 and 1.7. (orig.)

  20. Generation of parasitic axial flow by drift wave turbulence with broken symmetry: Theory and experiment

    Science.gov (United States)

    Hong, R.; Li, J. C.; Hajjar, R.; Chakraborty Thakur, S.; Diamond, P. H.; Tynan, G. R.

    2018-05-01

    Detailed measurements of intrinsic axial flow generation parallel to the magnetic field in the controlled shear decorrelation experiment linear plasma device with no axial momentum input are presented and compared to theory. The results show a causal link from the density gradient to drift-wave turbulence with broken spectral symmetry and development of the axial mean parallel flow. As the density gradient steepens, the axial and azimuthal Reynolds stresses increase and radially sheared azimuthal and axial mean flows develop. A turbulent axial momentum balance analysis shows that the axial Reynolds stress drives the radially sheared axial mean flow. The turbulent drive (Reynolds power) for the azimuthal flow is an order of magnitude greater than that for axial flow, suggesting that the turbulence fluctuation levels are set by azimuthal flow shear regulation. The direct energy exchange between axial and azimuthal mean flows is shown to be insignificant. Therefore, the axial flow is parasitic to the turbulence-zonal flow system and is driven primarily by the axial turbulent stress generated by that system. The non-diffusive, residual part of the axial Reynolds stress is found to be proportional to the density gradient and is formed due to dynamical asymmetry in the drift-wave turbulence.

  1. Manufacture of axially insulated large-area diodes

    International Nuclear Information System (INIS)

    Ma Weiyi; Zhou Kungang; Wang Youtian; Zhang Dong; Shan Yusheng; Wang Naiyan

    1999-01-01

    The author describes the design and construction of the axially insulated large-area diodes used in the 'Heaven-1'. The four axially insulated large-area diodes are connected to the 10 ohm pulse transmission lines via the vacuum feed through tubes. The experimental results with the diodes are given. The diodes can steadily work at the voltage of 650 kV, and the diode current density is about 80 A per cm 2 with a pulse width of 220 ns. The electron beams with a total energy of 25 kJ are obtained

  2. Axial nucleon form factors from lattice QCD

    International Nuclear Information System (INIS)

    Alexandrou, C.; Brinet, M.; Carbonell, J.; Harraud, P. A.; Papinutto, M.; Constantinou, M.; Guichon, P.; Jansen, K.; Korzec, T.

    2011-01-01

    We present results on the nucleon axial form factors within lattice QCD using two flavors of degenerate twisted mass fermions. Volume effects are examined using simulations at two volumes of spatial length L=2.1 fm and L=2.8 fm. Cut-off effects are investigated using three different values of the lattice spacings, namely a=0.089 fm, a=0.070 fm and a=0.056 fm. The nucleon axial charge is obtained in the continuum limit and chirally extrapolated to the physical pion mass enabling comparison with experiment.

  3. Topological invariants and the dynamics of an axial vector torsion field

    International Nuclear Information System (INIS)

    Drechsler, W.

    1983-01-01

    A generalized throry of gravitation is discussed which is based on a Riemann-Cartan space-time, U 4 , with an axial vector torsion field. Besides Einstein's equations determining the metric of the U 4 a system of nonlinear field equations is established coupling an axial vector source current to the axial vector torsion field. The properties of the solutions of these equations are discussed assuming a London-type condition relating the axial current and torsion field. To characterize the solutions use is made of the Euler and Pontrjagin forms and the associated quadratic curvature invariants for the U 4 space-time. It is found that there exists for a Riemann-Cartan space-time a relation between the zeros of the axial vector torsion field and the singularities of the Pontrjagin invariant, which is analogous to the well-known Hopf relation between the zeros of vector fields and the Euler characteristic. (author)

  4. Axial holdup in pulsed perforated-plate column of pulser feeder type, (2)

    International Nuclear Information System (INIS)

    Ikeda, Hidematsu; Suzuki, Atsuyuki; Kiyose, Ryohei.

    1987-01-01

    In mathematical models for a pulsed perforated-plate column, the dispersed phase holdup has been considered to be uniform throughout the length of the column, but fairly recently it is treated as being nonuniform. In the previous paper, the axial holdup data were obtained in the dispersed aqueous and the dispersed organic modes. Experimental results showed that the axial holdup data become nonuniform throughout the column. It was also found that both of the plate type and the operation mode affected the axial holdup distribution. The present work is an attempt to formulate the axial holdup by means of a heuristic selforganization method that provides a nonlinear prediction model of complex system, since the holdup data did not directly show so significant trend as to formulate the axial holdup. The Group Method of Data Handling (GMDH) is used for this purpose. The GMDH can be used for selection and synthesis of input variables concerned with the axial holdup for the pulsed perforated-plate column. The axial holdup data have been successfully correlated and the identification models could be useful in discussing mathematical models. (author)

  5. Evaluation of efficiency of axial profiling in WWER-440 fuel assemblies

    International Nuclear Information System (INIS)

    Ananjev, Yu. A.; Kurakin, K. Yu.; Artemov, V.G.; Ivanov, A.S.

    2005-01-01

    The present report deals with consideration of fuel enrichment axial profiling in WWER-440 assemblies. The study is performed on improving the effectiveness of fuel utilization using the example of implementing the axial profiling in the assemblies of the second generation. For simulation of fuel loadings the computer code package SAPFIR 9 5 and RC is used that allows for correct consideration of specific features of assemblies design changes. The methodical approach to assessment of effectiveness of implementing the axial profiling is considered with the use of capabilities of the mentioned code package. In conclusion the recommendations are given on using the fuel enrichment axial profiling in WWER-440 assemblies (Authors)

  6. Precautions against axial fan stall in reactor building to Tianwan NPP

    International Nuclear Information System (INIS)

    Liu Chunlong; Pei Junmin

    2011-01-01

    The paper introduces the mechanism and harm of rotating stall of axial fans, analyzes the necessity for prevention against axial fan stall in reactor building of Tianwan NPP, introduces the precautions, and then makes an assessment on anti-stall effect of flow separators. It can provide reference for model-selection or reconstruction of similar fans in power stations, and for operation and maintenance of axial fans. (authors)

  7. Microlitíase alveolar pulmonar: achados na tomografia computadorizada de alta resolução do tórax em 10 pacientes Pulmonary alveolar microlithiasis: high-resolution computed tomography findings in 10 patients

    Directory of Open Access Journals (Sweden)

    Edson Marchiori

    2007-10-01

    Full Text Available OBJETIVO: Apresentar os achados na tomografia computadorizada de alta resolução (TCAR do tórax da microlitíase alveolar pulmonar. MÉTODOS: Foram estudadas, retrospectivamente, as tomografias de dez pacientes adultos, sete mulheres e três homens, com idade média de 38,7 anos. Os exames foram analisados por dois radiologistas, de forma independente, e as decisões finais foram obtidas por consenso. RESULTADOS: Os achados mais freqüentes foram as opacidades em vidro fosco e as calcificações subpleurais, ambas presentes em 90% dos pacientes estudados. Os outros achados de maior relevância foram pequenos nódulos parenquimatosos, calcificação ao longo dos septos interlobulares, cissuras nodulares, nódulos subpleurais, cistos subpleurais, consolidações densas e padrão de pavimentação em mosaico. CONCLUSÕES: A microlitíase alveolar pulmonar apresenta aspectos na TCAR que são altamente sugestivos da doença, na maior parte dos casos dispensando a realização de biópsias pulmonares.OBJECTIVE: To present the high-resolution computed tomography (HRCT findings of pulmonary alveolar microlithiasis. METHODS: The HRCT scans of 10 adult patients (seven females and three males; mean age, 38.7 years were retrospectively analyzed. The films were studied independently by two radiologists. RESULTS: The most common tomographic findings were ground-glass attenuation and linear subpleural calcifications, which were seen in 90% of the patients. Other relevant findings were small parenchymal nodules, calcification along the interlobular septa, nodular cissures, subpleural nodules, subpleural cysts, dense consolidations, and a mosaic pattern of attenuation. CONCLUSIONS: The HRCT findings presented by individuals with pulmonary alveolar microlithiasis are distinct. In most cases, such findings can form the basis of the diagnosis, eliminating the need to perform a lung biopsy.

  8. Dynamic control of knee axial deformities

    Directory of Open Access Journals (Sweden)

    E. E. Malyshev

    2013-01-01

    Full Text Available The authors have evaluated the clinical examination of the patients with axial malalignments in the knee by the original method and device which was named varovalgometer. The measurements were conducted by tension of the cord through the spina iliaca anterior superior and the middle of the lower pole of patella. The deviation of the center of the ankle estimated by metal ruler which was positioned perpendicular to the lower leg axis on the level of the ankle joint line. The results of comparison of our method and computer navigation in 53 patients during the TKA show no statistically significant varieties but they differ by average 5° of valgus in clinical examination in comparison with mechanical axis which was identified by computer navigation. The dynamic control of axial malalignment can be used in clinical practice for estimation of the results of treatment of pathology with axial deformities in the knee; for the control of reduction and secondary displacement of the fractures around the knee; for assessment of instability; in planning of correctional osteotomies and intraoperative control of deformity correction; for estimation of Q angle in subluxation and recurrent dislocation of patella; in planning of TKA; during the growth of child it allows to assess the progression of deformity.

  9. Analysis of the axial filaments of Treponema hyodysenteriae by SDS-PAGE and immunoblotting.

    Science.gov (United States)

    Kent, K A; Sellwood, R; Lemcke, R M; Burrows, M R; Lysons, R J

    1989-06-01

    Purified axial filaments from eight serotypes of Treponema hyodysenteriae and two non-pathogenic intestinal spirochaetes were characterized by SDS-PAGE and Western blotting. Axial filaments of all ten strains had similar SDS-PAGE profiles; five major axial filament polypeptides were identified, with molecular masses of 43.8, 38, 34.8, 32.8 and 29.4 kDa. Hyperimmune gnotobiotic pig serum raised against purified axial filaments of strain P18A (serotype 4) cross-reacted with all other serotypes and with the non-pathogens, and convalescent serum taken from a pig with persistent swine dysentery also showed a strong response to the axial filament polypeptides. Hyperimmune gnotobiotic pig serum raised against axial filaments failed to agglutinate viable organisms and did not inhibit growth in vitro. Hence, the axial filaments of T. hyodysenteriae have been identified as major immunodominant antigens, although the role that antibodies to these antigens play in protection has yet to be established.

  10. Investigation of axial power gradients near a control rod tip

    Energy Technology Data Exchange (ETDEWEB)

    Loberg, John, E-mail: John.Loberg@fysast.uu.se [Uppsala University, Department of Physics and Astronomy, Division of Applied Nuclear Physics, Box 525, SE-75120 Uppsala (Sweden); Osterlund, Michael, E-mail: Michael.Osterlund@fysast.uu.se [Uppsala University, Department of Physics and Astronomy, Division of Applied Nuclear Physics, Box 525, SE-75120 Uppsala (Sweden); Bejmer, Klaes-Hakan, E-mail: Klaes-Hakan.Bejmer@vattenfall.com [Vattenfall Nuclear Fuel AB, Jaemtlandsgatan 99, 162 60 Vaellingby, Stockholm (Sweden); Blomgren, Jan, E-mail: Jan.Blomgren@vattenfall.com [Vattenfall Nuclear Fuel AB, Jaemtlandsgatan 99, 162 60 Vaellingby, Stockholm (Sweden); Kierkegaard, Jesper, E-mail: Jesper.Kierkegaar@vattenfall.com [Vattenfall Nuclear Fuel AB, Jaemtlandsgatan 99, 162 60 Vaellingby, Stockholm (Sweden)

    2011-07-15

    Highlights: > Pin power gradients near BWR control rod tips have been investigated. > A control rod tip is modeled in MCNP and compared to simplified 2D/3D geometry. > Small nodes increases pin power gradients; standard nodes underestimates gradients. > The MCNP results are validated against axial gamma scan of a controlled fuel pin. - Abstract: Control rod withdrawal in BWRs induces large power steps in the adjacent fuel assemblies. This paper investigates how well a 2D/3D method, e.g., CASMO5/SIMULATE5 computes axial pin power gradients adjacent to an asymmetrical control-rod tip in a BWR. The ability to predict pin power gradients accurately is important for safety considerations whereas large powers steps induced by control rod withdrawal can cause Pellet Cladding Interaction. The computation of axial pin power gradients axially around a control rod tip is a challenging task for any nodal code. On top of that, asymmetrical control rod handles are present in some BWR designs. The lattice code CASMO requires diagonal symmetry of all control rod parts. This introduces an error in computed pin power gradients that has been evaluated by Monte Carlo calculations. The results show that CASMO5/SIMULATE5, despite the asymmetrical control rod handle, is able to predict the axial pin power gradient within 1%/cm for axial nodal sizes of 15-3.68 cm. However, a nodal size of 3.68 cm still causes underestimations of pin power gradients compared with 1 cm nodes. Furthermore, if conventional node sizes are used, {approx}15 cm, pin power gradients can be underestimated by over 50% compared with 1 cm nodes. The detailed axial pin power profiles from MCNP are corroborated by measured gamma scan data on fuel rods irradiated adjacent to control rods.

  11. Bruch´s membrane thickness in relationship to axial length.

    Directory of Open Access Journals (Sweden)

    Hai Xia Bai

    Full Text Available To assess a potential role of Bruch´s membrane (BM in the biomechanics of the eye, we measured its thickness and the density of retinal pigment epithelium (RPE cells in various ocular regions in eyes of varying axial length.Human globes, enucleated because of an ocular tumor or end-stage glaucoma were prepared for histological examination. Using light microscopy, the histological slides were histomorphometrically examined applying a digitized image analysis system.The study included 104 eyes with a mean axial length of 27.9±3.2 mm (range:22.6mm-36.5mm. In eyes without congenital glaucoma, BM was significantly thickest (P<0.001 at the ora serrata, followed by the posterior pole, the midpoint between equator and posterior pole (MBEPP, and finally the equator. BM thickness was not significantly correlated with axial length (ora serrata: P = 0.93; equator:P = 0.31; MBEPP:P = 0.15; posterior pole:P = 0.35. RPE cell density in the pre-equatorial region (P = 0.02; regression coefficient r = -0.24 and in the retro-equatorial region (P = 0.03; r = -0.22 decreased with longer axial length, while RPE cell density at the ora serrata (P = 0.35, the MBEPP (P = 0.06; r = -0.19 and the posterior pole (P = 0.38 was not significantly correlated with axial length. Highly myopic eyes with congenital glaucoma showed a tendency towards lower BM thickness and lower RPE cell density at all locations.BM thickness, in contrast to scleral and choroidal thickness, was independent of axial length in eyes without congenital glaucoma. In association with an axial elongation associated decrease in the RPE cell density in the midperiphery, the findings support the notion of a biomechanical role BM may play in the process of emmetropization/myopization.

  12. Investigation of axial power gradients near a control rod tip

    International Nuclear Information System (INIS)

    Loberg, John; Osterlund, Michael; Bejmer, Klaes-Hakan; Blomgren, Jan; Kierkegaard, Jesper

    2011-01-01

    Highlights: → Pin power gradients near BWR control rod tips have been investigated. → A control rod tip is modeled in MCNP and compared to simplified 2D/3D geometry. → Small nodes increases pin power gradients; standard nodes underestimates gradients. → The MCNP results are validated against axial gamma scan of a controlled fuel pin. - Abstract: Control rod withdrawal in BWRs induces large power steps in the adjacent fuel assemblies. This paper investigates how well a 2D/3D method, e.g., CASMO5/SIMULATE5 computes axial pin power gradients adjacent to an asymmetrical control-rod tip in a BWR. The ability to predict pin power gradients accurately is important for safety considerations whereas large powers steps induced by control rod withdrawal can cause Pellet Cladding Interaction. The computation of axial pin power gradients axially around a control rod tip is a challenging task for any nodal code. On top of that, asymmetrical control rod handles are present in some BWR designs. The lattice code CASMO requires diagonal symmetry of all control rod parts. This introduces an error in computed pin power gradients that has been evaluated by Monte Carlo calculations. The results show that CASMO5/SIMULATE5, despite the asymmetrical control rod handle, is able to predict the axial pin power gradient within 1%/cm for axial nodal sizes of 15-3.68 cm. However, a nodal size of 3.68 cm still causes underestimations of pin power gradients compared with 1 cm nodes. Furthermore, if conventional node sizes are used, ∼15 cm, pin power gradients can be underestimated by over 50% compared with 1 cm nodes. The detailed axial pin power profiles from MCNP are corroborated by measured gamma scan data on fuel rods irradiated adjacent to control rods.

  13. Nuclear chiral axial currents and applications to few-nucleon systems

    Energy Technology Data Exchange (ETDEWEB)

    Baroni, Alessandro [Old Dominion Univ., Norfolk, VA (United States)

    2017-08-01

    This Thesis is divided into three main parts. The first part discusses basic aspects of chiral effective field theory and the formalism, based on time ordered perturbation theory, used to to derive the nuclear potentials and currents from the chiral Lagrangians. The second part deals with the actual derivation, up to one loop, of the two-nucleon potential and one- and two-nucleon weak axial charge and current. In both derivations ultraviolet divergences generated by loop corrections are isolated using dimensional regularization. The resulting axial current is finite and conserved in the chiral limit, while the axial charge requires renormalization. A complete set of contact terms for the axial charge up to the relevant order in the power counting is constructed. The third part of this Thesis discusses two applications: (i) the calculation of the Gamow-Teller matrix element of tritium, used to constrain the single low-energy constant entering the axial current; (ii) the calculation of neutrino-deuteron inclusive cross sections at low energies. These results have confirmed previous predictions obtained in phenomenological approaches. These latter studies have played an important role in the analysis and interpretation of experiments at the Sudbury Neutrino Observatory.

  14. Reconstruction of core axial power shapes using the alternating conditional expectation algorithm

    International Nuclear Information System (INIS)

    Lee, Eun Ki; Kim, Yong Hee; Cha, Kune Ho; Park, Moon Ghu

    1999-01-01

    We have introduced the alternating conditional expectation (ACE) algorithm in reconstructing 20-node axial core power shapes from five-level in-core detector powers. The core design code, Reactor Operation and Control Simulation (ROCS), calculates 3-dimensional power distributions for various core states, and the reference core-averaged axial power shapes and corresponding simulated detector powers are utilized to synthesize the axial power shape. By using the ACE algorithm, the optimal relationship between a dependent variable, the plane power, and independent variables, five detector powers, is determined without any preprocessing. A total of ∼3490 data sets per each cycle of YongGwang Nuclear (YGN) power plant units 3 and 4 is used for the regression. Continuous analytic function corresponding to each optimal transformation is calculated by simple regression model. The reconstructed axial power shapes of ∼21,200 cases are compared to the original ROCS axial power shapes. Also, to test the validity and accuracy of the new method, its performance is compared with that of the Fourier fitting method (FFM), a typical method of the deterministic approach. For a total of 21,204 data cases, the averages of root mean square (rms) error, axial peak error (ΔF z ), and axial shape index error (ΔASI) of new method are calculated as 0.81%, 0.51% and 0.00204, while those of FFM are 2.29%, 2.37% and 0.00264, respectively. We also evaluated the wide range of axial power profiles from the xenon-oscillation. The results show that the newly developed method is far superior to FFM; average rms and axial peak error are just ∼35 and ∼20% of those of FFM, respectively

  15. What changed during the axial age: Cognitive styles or reward systems?

    Science.gov (United States)

    Baumard, Nicolas; Hyafil, Alexandre; Boyer, Pascal

    2015-01-01

    The ‘Axial Age’ (500–300 BCE) refers to the period during which most of the main religious and spiritual traditions emerged in Eurasian societies. Although the Axial Age has recently been the focus of increasing interest,1-5 its existence is still very much in dispute. The main reason for questioning the existence of the Axial Age is that its nature, as well as its spatial and temporal boundaries, remain very much unclear. The standard approach to the Axial Age defines it as a change of cognitive style, from a narrative and analogical style to a more analytical and reflective style, probably due to the increasing use of external memory tools. Our recent research suggests an alternative hypothesis, namely a change in reward orientation, from a short-term materialistic orientation to a long-term spiritual one.6 Here, we briefly discuss these 2 alternative definitions of the Axial Age. PMID:27066164

  16. Axial gravity, massless fermions and trace anomalies

    International Nuclear Information System (INIS)

    Bonora, L.; Cvitan, M.; Giaccari, S.; Stemberga, T.; Prester, P.D.; Pereira, A.D.; UFF-Univ. Federal Fluminense, Niteroi

    2017-01-01

    This article deals with two main topics. One is odd parity trace anomalies in Weyl fermion theories in a 4d curved background, the second is the introduction of axial gravity. The motivation for reconsidering the former is to clarify the theoretical background underlying the approach and complete the calculation of the anomaly. The reference is in particular to the difference between Weyl and massless Majorana fermions and to the possible contributions from tadpole and seagull terms in the Feynman diagram approach. A first, basic, result of this paper is that a more thorough treatment, taking account of such additional terms and using dimensional regularization, confirms the earlier result. The introduction of an axial symmetric tensor besides the usual gravitational metric is instrumental to a different derivation of the same result using Dirac fermions, which are coupled not only to the usual metric but also to the additional axial tensor. The action of Majorana and Weyl fermions can be obtained in two different limits of such a general configuration. The results obtained in this way confirm the previously obtained ones. (orig.)

  17. Axial gravity, massless fermions and trace anomalies

    Energy Technology Data Exchange (ETDEWEB)

    Bonora, L. [International School for Advanced Studies (SISSA), Trieste (Italy); KEK, Tsukuba (Japan). KEK Theory Center; INFN, Sezione di Trieste (Italy); Cvitan, M.; Giaccari, S.; Stemberga, T. [Zagreb Univ. (Croatia). Dept. of Physics; Prester, P.D. [Rijeka Univ. (Croatia). Dept. of Physics; Pereira, A.D. [UERJ-Univ. Estadual do Rio de Janeiro (Brazil). Dept. de Fisica Teorica; UFF-Univ. Federal Fluminense, Niteroi (Brazil). Inst. de Fisica

    2017-08-15

    This article deals with two main topics. One is odd parity trace anomalies in Weyl fermion theories in a 4d curved background, the second is the introduction of axial gravity. The motivation for reconsidering the former is to clarify the theoretical background underlying the approach and complete the calculation of the anomaly. The reference is in particular to the difference between Weyl and massless Majorana fermions and to the possible contributions from tadpole and seagull terms in the Feynman diagram approach. A first, basic, result of this paper is that a more thorough treatment, taking account of such additional terms and using dimensional regularization, confirms the earlier result. The introduction of an axial symmetric tensor besides the usual gravitational metric is instrumental to a different derivation of the same result using Dirac fermions, which are coupled not only to the usual metric but also to the additional axial tensor. The action of Majorana and Weyl fermions can be obtained in two different limits of such a general configuration. The results obtained in this way confirm the previously obtained ones. (orig.)

  18. On the problem of axial anomaly in supersymmetric gauge theories

    International Nuclear Information System (INIS)

    Kazakov, D.I.

    1984-01-01

    The explicit relation is found between the axial current obeying the Adler-Bardeen theorem and the supersymmetric one belonging to a supermultiplet. It is shown that the axial and superconformal anomalies are consistent in all orders of perturbation theory

  19. Metamorphosis of helical magnetorotational instability in the presence axial electric current

    OpenAIRE

    Priede, Jānis

    2014-01-01

    This paper presents numerical linear stability analysis of a cylindrical Taylor-Couette flow of liquid metal carrying axial electric current in a generally helical external magnetic field. Axially symmetric disturbances are considered in the inductionless approximation corresponding to zero magnetic Prandtl number. Axial symmetry allows us to reveal an entirely new electromagnetic instability. First, we show that the electric current passing through the liquid can extend the range of helical ...

  20. Progressive atlanto-axial subluxation in Behcet's disease

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sang-hyuk [Chonbuk National University Hospital, Department of Neurosurgery, Jeonju City, Jeonbuk (Korea); Eoh, Whan [Sungkyunkwan University School of Medicine, Samsung Medical Center, Department of Neurosurgery, Seoul (Korea)

    2010-03-15

    Behcet's disease is a chronic inflammatory condition involving several organs, such as the skin, mucous membranes, eyes, joints, intestines, lungs and central nervous system. It rarely affects the spinal column. We describe a case of progressive atlanto-axial subluxation in a 44-year-old woman with Behcet's disease. The patient started complaining of posterior neck pain 10 years after the diagnosis of her Behcet's disease. Initial radiographs showed no abnormal finding, but follow-up radiographs 6 month later demonstrated atlanto-axial subluxation. To the best of our knowledge, this is the second reported case in the worldwide literature of an atlanto-axial instability in a patient with Behcet's disease. (orig.)

  1. Development of axial tomography technique for the study of steam explosion

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Young; Seo, S. W.; You, S. [Handong Golbal Univ., Pohang (Korea, Republic of)

    2006-05-15

    In this report, axial tomography applying to steam explosion is implemented. When steam explosion experiment is performed, we have seen the difficulty with physical modeling due to the complex phenomena of generated steam, propagation of shock wave and bubble breakup and coalescence. Hence, the uncertainty due to these phenomena is occurred. The fast and global measurement of the steam distribution is imperative to understand the complex phenomena performed during the steam explosion, KAERI have developed the fast and global measuring instrument to monitor such phenomena of axial steam distribution. Generally, X-ray is used as measuring method, but this method is very expensive and has limited measurement area. So we need new method that can substitute X-ray method and in this research, ECT method is replaced. The research is performed dividing within two parts: Software and Hardware. In the software part, the electric field analysis code and algorithm for inverse projection were developed. And, in the hardware part, capacitance measurement circuit is developed to measure up to fF level. Operable axial tomography was analyzed with concept design of axial tomography appropriate to steam explosion accident and analysis code for axial electric field analysis and inverse algorithm were developed, moreover, designing signal analysis system for axial tomography was performed.

  2. Axial sidelobe reduction in single-photon 4Pi microscopy by Toraldo filters

    International Nuclear Information System (INIS)

    Martinex-Corral, M.; Pons, A.; Caballero, M.T.

    2002-01-01

    Full text: The 4Pi-confocal fluorescence microscope is a recently developed 3D imaging technique in which two opposing high-NA objectives are used for coherently illuminating and/or detecting the same point of the fluorescent sample. The interference process yields an intensity point spread function (PSF) with an extremely narrow axial core, but with very large axial sidelobes, which compromise the actual improvement in axial resolution. To overcome this problem we propose the use, in the illumination arm of the 4Pi-confocal microscope, of multiple-zones phase filters whose design is based on the Toraldo-design principle. Note that the Toraldo procedure allows to select at will the positions of the zeros of the PSF of an optical system. Then, what we propose here if to design a phase pupil filter such that the position of the first zero of the illumination axial PSF is close to the position of the maximum of the first axial sidelobe of the detection PSF. In the design procedure it is taken into account that: 1. The value of the parameter ε = λ exc /λ det which, in a single-photon fluorescent process, is the responsible for the different scales of the illumination and detection PSFs. 2. The Toraldo procedure was originally designed to control the position of zeros of the transverse PSF. In this case the procedure is adapted to the aim of controlling the position of zeros of the axial PSF. 3. Since 4Pi-confocal microscopes are only useful when built with high-NA objectives, the Toraldo principle is reformulated in terms of the nonparaxial diffraction theory. We show that by using Toraldo filters in the illumination part of a 4Pi-confocal microscope it is possible to obtain up to a 60% reduction of height of the axial sidelobe of the whole-system axial PSF. This fact permits to fully benefit the axial resolution from the strong narrowness of the central peak of the axial PSF, inherent to the 4Pi principle. Copyright (2002) Australian Society for Electron Microscopy

  3. Axial structure of the nucleon

    Energy Technology Data Exchange (ETDEWEB)

    Veronique Bernard; Latifa Elouadrhiri; Ulf-G Meissner

    2002-01-01

    We review the current status of experimental and theoretical understanding of the axial nucleon structure at low and moderate energies. Topics considered include (quasi)elastic (anti)neutrino-nucleon scattering, charged pion electroproduction off nucleons and ordinary as well as radiative muon capture on the proton.

  4. Method to Measure Tone of Axial and Proximal Muscle

    Science.gov (United States)

    Gurfinkel, Victor S.; Cacciatore, Timothy W.; Cordo, Paul J.; Horak, Fay B.

    2011-01-01

    The control of tonic muscular activity remains poorly understood. While abnormal tone is commonly assessed clinically by measuring the passive resistance of relaxed limbs1, no systems are available to study tonic muscle control in a natural, active state of antigravity support. We have developed a device (Twister) to study tonic regulation of axial and proximal muscles during active postural maintenance (i.e. postural tone). Twister rotates axial body regions relative to each other about the vertical axis during stance, so as to twist the neck, trunk or hip regions. This twisting imposes length changes on axial muscles without changing the body's relationship to gravity. Because Twister does not provide postural support, tone must be regulated to counteract gravitational torques. We quantify this tonic regulation by the restive torque to twisting, which reflects the state of all muscles undergoing length changes, as well as by electromyography of relevant muscles. Because tone is characterized by long-lasting low-level muscle activity, tonic control is studied with slow movements that produce "tonic" changes in muscle length, without evoking fast "phasic" responses. Twister can be reconfigured to study various aspects of muscle tone, such as co-contraction, tonic modulation to postural changes, tonic interactions across body segments, as well as perceptual thresholds to slow axial rotation. Twister can also be used to provide a quantitative measurement of the effects of disease on axial and proximal postural tone and assess the efficacy of intervention. PMID:22214974

  5. Memoria de trabajo en niños escolarizados: efecto de intervalos de presentación y distractores en la prueba computarizada Memonum

    Directory of Open Access Journals (Sweden)

    Carlos Arturo Conde Cotes

    2013-06-01

    Full Text Available La presente investigación evaluó la memoria de trabajo visual a través de la prueba computarizada Memonum en niños escolarizados. Se evaluaron los efectos de tres tiempos de exposición (1, 4 y 8 segundos y de la presentación de un distractor sobre el desempeño mnemónico en la prueba Memonum en 72 niños pertenecientes a un colegio del área metropolitana de Bucaramanga, Colombia, con edades entre 8 y 11 años de los grados tercero, cuarto y quinto de primaria. Se encontró una diferencia significativa entre los tiempos de exposición en las variables número de aciertos y aciertos acumulados, demostrandoun mejor desempeño mnemónico en los participantes que presentaron la prueba en el tiempo de 8 segundos en comparación con los niños pertenecientes al grupo de 1 segundo; además, la presencia del distractor demostró una diferencia significativa en los aciertos y aciertos acumulados, considerándose como un estímulo generador de interferencia que perturba la capacidad de almacenamiento de la memoria de trabajo en niños. Adicionalmente, se halló una diferencia significativa en cuanto al uso de la estrategia de repetición mental, indicando que los participantes de los grupos de 4 y 8 segundos leasignaron mayor puntaje que los niños del grupo de 1 segundo. Un amplio tiempo de exposición de estímulos en la prueba Memonum aumenta la capacidad de retención; asimismo, el empleo de un distractor afecta en los participantes la capacidad de almacenamiento y esta, a suvez, aumenta de acuerdo a la progresión escolar, debidoal uso de las estrategias mnemónicas que los niños utilizan para garantizar el recuerdo de las series numéricas.

  6. Modelling larval transport in a axial convergence front

    Science.gov (United States)

    Robins, P.

    2010-12-01

    Marine larvae exhibit different vertical swimming behaviours, synchronised by factors such as tidal currents and daylight, in order to aid retention near the parent populations and hence promote production, avoid predation, or to stimulate digestion. This paper explores two types of larval migration in an estuarine axial convergent front which is an important circulatory mechanism in many coastal regions where larvae are concentrated. A parallelised, three-dimensional, ocean model was applied to an idealised estuarine channel which was parameterised from observations of an axial convergent front which occurs in the Conwy Estuary, U.K. (Nunes and Simpson, 1985). The model successfully simulates the bilateral cross-sectional recirculation of an axial convergent front, which has been attributed to lateral density gradients established by the interaction of the lateral shear of the longitudinal currents with the axial salinity gradients. On the flood tide, there is surface axial convergence whereas on the ebb tide, there is (weaker) surface divergence. Further simulations with increased/decreased tidal velocities and with stronger/weaker axial salinity gradients are planned so that the effects of a changing climate on the secondary flow can be understood. Three-dimensional Lagrangian Particle Tracking Models (PTMs) have been developed which use the simulated velocity fields to track larvae in the estuarine channel. The PTMs take into account the vertical migrations of two shellfish species that are commonly found in the Conwy Estuary: (i) tidal migration of the common shore crab (Carcinus maenas) and (ii), diel (daily) migration of the Great scallop (Pecten maximus). These migration behaviours are perhaps the most widespread amongst shellfish larvae and have been compared with passive (drifting) particles in order to assess their relative importance in terms of larval transport. Preliminary results suggest that the net along-estuary dispersal over a typical larval

  7. Axial loaded MRI of the lumbar spine

    Energy Technology Data Exchange (ETDEWEB)

    Saifuddin, A. E-mail: asaifuddin@aol.com; Blease, S.; MacSweeney, E

    2003-09-01

    Magnetic resonance imaging is established as the technique of choice for assessment of degenerative disorders of the lumbar spine. However, it is routinely performed with the patient supine and the hips and knees flexed. The absence of axial loading and lumbar extension results in a maximization of spinal canal dimensions, which may in some cases, result in failure to demonstrate nerve root compression. Attempts have been made to image the lumbar spine in a more physiological state, either by imaging with flexion-extension, in the erect position or by using axial loading. This article reviews the literature relating to the above techniques.

  8. Cross-flow filtration and axial filtration

    International Nuclear Information System (INIS)

    Kraus, K.A.

    1974-01-01

    Two relatively novel alternative solid-liquid-separation techniques of filtration are discussed. In cross-flow filtration, the feed is pumped past the filtering surface. While in axial filtration the filter, mounted on a rotor, is moved with respect to the feed. While large-scale application of the axial filter is still in doubt, it permits with little expenditure of time and money, duplication of many hydrodynamic aspects of cross-flow filtration for fine-particle handling problems. The technique has been applied to municipal wastes, low-level radioactive waste treatment plant, lead removal from industrial wastes, removal of pulp-mill contaminants, textile-mill wastes, and pretreatment of saline waters by lime-soda process in preparation for hyperfiltration. Economics and energy requirements are also discussed

  9. Development of Performance Analysis Program for an Axial Compressor with Meanline Analysis

    International Nuclear Information System (INIS)

    Park, Jun Young; Park, Moo Ryong; Choi, Bum Suk; Song, Je Wook

    2009-01-01

    Axial-flow compressor is one of the most important parts of gas turbine units with axial turbine and combustor. Therefore, precise prediction of performance is very important for development of new compressor or modification of existing one. Meanline analysis is a simple, fast and powerful method for performance prediction of axial-flow compressors with different geometries. So, Meanline analysis is frequently used in preliminary design stage and performance analysis for given geometry data. Much correlations for meanline analysis have been developed theoretically and experimentally for estimating various types of losses and flow deviation angle for long time. In present study, meanline analysis program was developed to estimate compressor losses, incidence angles, deviation angles, stall and surge conditions with many correlations. Performance prediction of one stage axial compressors is conducted with this meanline analysis program. The comparison between experimental and numerical results show a good agreement. This meanline analysis program can be used for various types of single stage axial-flow compressors with different geometries, as well as multistage axial-flow compressors

  10. Xenon-induced axial power oscillations in the 400 MW PBMR

    International Nuclear Information System (INIS)

    Strydom, Gerhard

    2008-01-01

    The redistribution of the spatial xenon concentration in the 400 MW Pebble Bed Modular Reactor (PBMR) core has a non-linear, time-dependent feedback effect on the spatial power density during several types of operational transient events. Due to the inherent weak coupling that exists between the iodine and xenon formation and destruction rates, as well as the complicating effect of spatial variance in the thermal flux field, reactor cores have been analyzed for a number of decades for the occurrence and severity of xenon-induced axial power oscillations. Of specific importance is the degree of oscillation damping exhibited by the core during transients, which involves axial variations in the local power density. In this paper the TINTE reactor dynamics code is used to assess the stability of the current 400 MW PBMR core design with regard to axial xenon oscillations. The focus is mainly on the determination of the inherent xenon and power oscillation damping properties by utilizing a set of hypothetical control rod insertion transients at various power levels. The oscillation damping properties of two 100%-50%-100% load-follow transients, one of which includes the de-stabilizing axial effects of moving control rods, are also discussed in some detail. The study shows that, although first axial mode oscillations do occur in the 400 MW PBMR core, the inherent damping of these oscillations is high, and that none of the investigated load-follow transients resulted in diverging oscillations. It is also shown that the PBMR core exhibits no radial oscillation components for these xenon-induced axial power oscillations

  11. A study on multi-axial fatigue model based on structural stress

    International Nuclear Information System (INIS)

    Kim, Cheol; Kim, Jong Sung; Jin, Tae Eun; Dong, P.

    2004-01-01

    In nuclear components, cyclic loadings that cause complex states of stress are common. Through a reference review, four sources of the multi-axial fatigue data were collected from LBF, University of Illinois, EPRI, and TWI. All these tests were conducted using tube to flange specimens with a circumferential fillet welds. The loading conditions were mostly bending/ torsion combinations, except that TWI used tension/ torsion combinations. None of fatigue correlation parameters have been demonstrated to be satisfactory in correlating the multi-axial fatigue data outside of their own. In this paper, we proposed the characterizing multi-axial fatigue behavior in terms of the structural stress methods by using some of the well-known multi-axial fatigue data available in the references

  12. Precision axial translator with high stability.

    Science.gov (United States)

    Bösch, M A

    1979-08-01

    We describe a new type of translator which is inherently stable against torsion and twisting. This concentric translator is also ideally suited for precise axial motion with clearance of the center line.

  13. Axially modulated arch resonator for logic and memory applications

    KAUST Repository

    Hafiz, Md Abdullah Al

    2018-01-17

    We demonstrate reconfigurable logic and random access memory devices based on an axially modulated clamped-guided arch resonator. The device is electrostatically actuated and the motional signal is capacitively sensed, while the resonance frequency is modulated through an axial electrostatic force from the guided side of the microbeam. A multi-physics finite element model is used to verify the effectiveness of the axial modulation. We present two case studies: first, a reconfigurable two-input logic gate based on the linear resonance frequency modulation, and second, a memory element based on the hysteretic frequency response of the resonator working in the nonlinear regime. The energy consumptions of the device for both logic and memory operations are in the range of picojoules, promising for energy efficient alternative computing paradigm.

  14. Avaliação da concordância interobservador na análise da tomografia computadorizada sem contraste no diagnóstico da urolitíase em pacientes com cólica renal aguda Interobserver agreement on non-contrast computed tomography interpretation for diagnosis of urolithiasis in patients with acute flank pain

    Directory of Open Access Journals (Sweden)

    Luís Ronan Marquez Ferreira de Souza

    2006-10-01

    Full Text Available OBJETIVO: Avaliar a reprodutibilidade da tomografia computadorizada sem contraste na avaliação da litíase ureteral e os sinais secundários de obstrução do sistema coletor em pacientes com cólica renal aguda. MATERIAIS E MÉTODOS: Estudo prospectivo de 52 pacientes com diagnóstico clínico de cólica renal aguda submetidos a exame de tomografia computadorizada de abdome sem contraste. Os exames foram realizados com técnica helicoidal e posteriormente analisados por três observadores independentes, com a concordância interobservador avaliada pelo método estatístico kappa (kapa. Foram analisados os parâmetros: a presença, localização e mensuração dos cálculos ureterais; b dilatação do sistema coletor intra-renal; c heterogeneidade da gordura perirrenal; d dilatação ureteral; e edema da parede ureteral (sinal do halo. RESULTADOS: Foram encontrados 40 cálculos ureterais na tomografia computadorizada (77%. A concordância interobservador para a identificação do cálculo ureteral e da dilatação ureteral foi quase perfeita (kapa = 0,89 e kapa = 0,87, respectivamente, substancial para dilatação do sistema coletor intra-renal (kapa = 0,77 e moderada para heterogeneidade da gordura perirrenal e para edema da parede ureteral (kapa = 0,55 e kapa = 0,56, respectivamente. CONCLUSÃO: A tomografia computadorizada de abdome sem contraste apresenta elevada reprodutibilidade na avaliação da litíase ureteral e dos sinais secundários de obstrução do sistema coletor.OBJECTIVE: To evaluate the interobserver agreement on non-contrast computed tomography interpretation by a group of experienced abdominal radiologists, for the study of urolithiasis in patients presenting acute flank pain. MATERIALS AND METHODS: Prospective study of 52 patients submitted to non-contrast enhanced helical computed tomography. The images were subsequently analyzed by three independent observers, with the interobserver agreement assessed by means of the

  15. Investigation on a procedure for optimal axial depth of cut accuracy in micromilling

    DEFF Research Database (Denmark)

    Bissacco, Giuliano; Hansen, Hans Nørgaard; De Chiffre, Leonardo

    2005-01-01

    On the basis of a previously developed procedure for control of axial depth of cut in high accuracy micromilling operations, this paper presents an investigation on the estimation of the uncertainty of the set axial depth of cut.......On the basis of a previously developed procedure for control of axial depth of cut in high accuracy micromilling operations, this paper presents an investigation on the estimation of the uncertainty of the set axial depth of cut....

  16. Asymptotic freedom in the axial and Coulomb gauges

    International Nuclear Information System (INIS)

    Frenkel, J.; Taylor, J.C.

    1976-01-01

    The sources of the negative contribution to the charge renormalization factor gsup(B)/g-1 in Yang-Mills theories are investigated in the axial and Coulomb gauges. In the axial gauge, a Kaellen dispersion relation exists but the spectral function is not positive definite because of the prescription that is used to integrate the singular polarization vectors. In the Coulomb gauge, the negative contributions are (to the lowest order) isolated in the Coulomb self-energy corrections to the Coulomb field. (Auth.)

  17. Effects of axial coordination on immobilized Mn(salen) catalysts.

    Science.gov (United States)

    Teixeira, Filipe; Mosquera, Ricardo A; Melo, André; Freire, Cristina; Cordeiro, M Natália D S

    2014-11-13

    The consequences of anchoring Mn(salen) catalysts onto a supporting material using one of the vacant positions of the metal center are tackled by studying several Mn(salen) complexes with different axial ligands attached. This is accomplished using Density Functional Theory at the X3LYP/Triple-ζ level of theory and the Atom In Molecules formalism. The results suggest that both Mn(salen) complexes and their oxo derivatives should lie in a triplet ground state. Also, the choice of the axial ligand bears a moderate effect on the energy involved in the oxidation of the former to oxo-Mn(salen) complexes, as well as in the stability of such complexes toward ligand removal by HCl. AIM analysis further suggests that the salen ligand acts as a "charge reservoir" for the metal center, with strong correlations being obtained between the charge of salen and the electron population donated by the axial ligand to the metal center. Moreover, the results suggest that the Mn atom in Mn(salen) complexes holds different hybridization of its valence orbitals depending on the type of axial ligand present in the system.

  18. Axial magnetic field restriction of plasma sheath in a coaxial discharge

    International Nuclear Information System (INIS)

    Masoud, M. M.; Soliman, H. M.; Ibrahim, F. A.

    1999-01-01

    The study deals with the effect of an applied axial magnetic field on the dynamics and parameters of the plasma sheath and the expanded plasma in a coaxial discharge. Experimental investigations were carried out with a 3 kJ coaxial discharge device of a Mather geometry. The discharge takes place in Hydrogen gas with base pressure of 1 torr. The experiments were conducted with a 10 kV bank voltage, which corresponds to 100 kA discharge currents. The investigations have shown that the maximum axial plasma sheath velocity is decreased by 20% when applying the external axial magnetic field along the coaxial electrodes of intensity 2.6 kG. The experimental results of axial magnetic field intensity B z along the coaxial electrodes indicated that the application of external axial magnetic field causes an increases of B z ∼ 40% at a mid-distance between the breech and the muzzle and a decrease by 75% at the muzzle. The experimental results of expanded plasma electron temperature T e and density n e cleared that when the axial magnetic field is applied the maximum T e is decreased by 2.6 and 3 times, while the maximum n e is increased by 2.8 and 2 times for the first and second half cycles respectively. (author)

  19. Efficient Propulsion Structure with an Axial Flux Rotary Converter for HEV Drive Unit

    Directory of Open Access Journals (Sweden)

    Ales Havel

    2011-01-01

    Full Text Available This paper describes an efficient axial flux arrangement of the four quadrant rotary converter for hybrid electric vehicles. The design of the axial flux wound stator and both axial flux squirrel cage rotors is based on the arrangement of radial air gap induction motor and permanent magnet synchronous motor. The method of constant magnetic circuit volume is utilized for dimensions conversion, which results into basic dimensions of stator and rotor discs in axial flux conception. This allows the creation of real 3D models in the CAD application. Finally, the finite element simulations of electromagnetic induction in the axial flux stator pack are presented in the concluding part of this paper.

  20. Axial and radial velocities in the creeping flow in a pipe

    Directory of Open Access Journals (Sweden)

    Zuykov Andrey L'vovich

    2014-05-01

    Full Text Available The article is devoted to analytical study of transformation fields of axial and radial velocities in uneven steady creeping flow of a Newtonian fluid in the initial portion of the cylindrical channel. It is shown that the velocity field of the flow is two-dimensional and determined by the stream function. The article is a continuation of a series of papers, where normalized analytic functions of radial axial distributions in uneven steady creeping flow in a cylindrical tube with azimuthal vorticity and stream function were obtained. There is Poiseuille profile for the axial velocity in the uniform motion of a fluid at an infinite distance from the entrance of the pipe (at x = ∞, here taken equal to zero radial velocity. There is uniform distribution of the axial velocity in the cross section at the tube inlet at x = 0, at which the axial velocity is constant along the current radius. Due to the axial symmetry of the flow on the axis of the pipe (at r = 0, the radial velocities and the partial derivative of the axial velocity along the radius, corresponding to the condition of the soft function extremum, are equal to zero. The authors stated vanishing of the velocity of the fluid on the walls of the pipe (at r = R , where R - radius of the tube due to its viscous sticking and tightness of the walls. The condition of conservation of volume flow along the tube was also accepted. All the solutions are obtained in the form of the Fourier - Bessel. It is shown that the hydraulic losses at uniform creeping flow of a Newtonian fluid correspond to Poiseuille - Hagen formula.

  1. Axial length elongation in adults with long-standing unilateral traumatic cataract

    Directory of Open Access Journals (Sweden)

    Jonel Steffen

    2016-09-01

    Full Text Available Background: Unilateral eye elongation with resultant axial myopia has been reported to occur secondary to visual deprivation from birth or early childhood. Acquired axial length elongation secondary to visual deprivation in adults has rarely been reported. Aim: To report acquired axial myopia in adults with visual deprivation due to long-standing unilateral traumatic cataract. Methods: Eleven consecutive adult patients who presented for cataract surgery with unilateral, long-standing, mature, traumatic cataracts and an interocular axial length difference of more than 1 mm were studied. Patients with a post-operative best corrected visual acuity (BCVA of < 6/12 were excluded to rule out possible pre-existing anisometropic amblyopia. Results: Of the 11 patients with significant interocular axial length difference, 5 patients were excluded on the basis of possible pre-existing amblyopia. The remaining 6 patients had final BCVA of 6/12 or better. The median length of the cataractous eyes was 2.83 mm longer than the fellow eyes (range 1.12 mm – 3.52 mm. The intraocular lens power required for emmetropia was 6.8 dioptres (range 3.5 dioptres – 11.5 dioptres less in the cataractous eyes. A refractive outcome within 1 dioptre of the target refraction was achieved in all patients. The median delay between ocular trauma and cataract surgery was 20 years (range 8–24 years. Conclusion: Significant unilateral axial length elongation may occur in adults with longstanding traumatic cataracts and visual deprivation. A potential correlation may exist between delay to surgery and degree of axial length difference. This rare phenomenon must be considered when determining intraocular lens power to avoid post-operative refractive surprises.

  2. Computational analysis of a multistage axial compressor

    Science.gov (United States)

    Mamidoju, Chaithanya

    Turbomachines are used extensively in Aerospace, Power Generation, and Oil & Gas Industries. Efficiency of these machines is often an important factor and has led to the continuous effort to improve the design to achieve better efficiency. The axial flow compressor is a major component in a gas turbine with the turbine's overall performance depending strongly on compressor performance. Traditional analysis of axial compressors involves throughflow calculations, isolated blade passage analysis, Quasi-3D blade-to-blade analysis, single-stage (rotor-stator) analysis, and multi-stage analysis involving larger design cycles. In the current study, the detailed flow through a 15 stage axial compressor is analyzed using a 3-D Navier Stokes CFD solver in a parallel computing environment. Methodology is described for steady state (frozen rotor stator) analysis of one blade passage per component. Various effects such as mesh type and density, boundary conditions, tip clearance and numerical issues such as turbulence model choice, advection model choice, and parallel processing performance are analyzed. A high sensitivity of the predictions to the above was found. Physical explanation to the flow features observed in the computational study are given. The total pressure rise verses mass flow rate was computed.

  3. High-resolution axial MR imaging of tibial stress injuries

    Directory of Open Access Journals (Sweden)

    Mammoto Takeo

    2012-05-01

    Full Text Available Abstract Purpose To evaluate the relative involvement of tibial stress injuries using high-resolution axial MR imaging and the correlation with MR and radiographic images. Methods A total of 33 patients with exercise-induced tibial pain were evaluated. All patients underwent radiograph and high-resolution axial MR imaging. Radiographs were taken at initial presentation and 4 weeks later. High-resolution MR axial images were obtained using a microscopy surface coil with 60 × 60 mm field of view on a 1.5T MR unit. All images were evaluated for abnormal signals of the periosteum, cortex and bone marrow. Results Nineteen patients showed no periosteal reaction at initial and follow-up radiographs. MR imaging showed abnormal signals in the periosteal tissue and partially abnormal signals in the bone marrow. In 7 patients, periosteal reaction was not seen at initial radiograph, but was detected at follow-up radiograph. MR imaging showed abnormal signals in the periosteal tissue and entire bone marrow. Abnormal signals in the cortex were found in 6 patients. The remaining 7 showed periosteal reactions at initial radiograph. MR imaging showed abnormal signals in the periosteal tissue in 6 patients. Abnormal signals were seen in the partial and entire bone marrow in 4 and 3 patients, respectively. Conclusions Bone marrow abnormalities in high-resolution axial MR imaging were related to periosteal reactions at follow-up radiograph. Bone marrow abnormalities might predict later periosteal reactions, suggesting shin splints or stress fractures. High-resolution axial MR imaging is useful in early discrimination of tibial stress injuries.

  4. High-resolution axial MR imaging of tibial stress injuries

    Science.gov (United States)

    2012-01-01

    Purpose To evaluate the relative involvement of tibial stress injuries using high-resolution axial MR imaging and the correlation with MR and radiographic images. Methods A total of 33 patients with exercise-induced tibial pain were evaluated. All patients underwent radiograph and high-resolution axial MR imaging. Radiographs were taken at initial presentation and 4 weeks later. High-resolution MR axial images were obtained using a microscopy surface coil with 60 × 60 mm field of view on a 1.5T MR unit. All images were evaluated for abnormal signals of the periosteum, cortex and bone marrow. Results Nineteen patients showed no periosteal reaction at initial and follow-up radiographs. MR imaging showed abnormal signals in the periosteal tissue and partially abnormal signals in the bone marrow. In 7 patients, periosteal reaction was not seen at initial radiograph, but was detected at follow-up radiograph. MR imaging showed abnormal signals in the periosteal tissue and entire bone marrow. Abnormal signals in the cortex were found in 6 patients. The remaining 7 showed periosteal reactions at initial radiograph. MR imaging showed abnormal signals in the periosteal tissue in 6 patients. Abnormal signals were seen in the partial and entire bone marrow in 4 and 3 patients, respectively. Conclusions Bone marrow abnormalities in high-resolution axial MR imaging were related to periosteal reactions at follow-up radiograph. Bone marrow abnormalities might predict later periosteal reactions, suggesting shin splints or stress fractures. High-resolution axial MR imaging is useful in early discrimination of tibial stress injuries. PMID:22574840

  5. Imaging features suggestive of a conjoined nerve root on routine axial MRI

    Energy Technology Data Exchange (ETDEWEB)

    Song, Su Jin; Lee, Joon Woo; Kang, Heung Sik [Seoul National University Bundang Hospital, Department of Radiology, Gyeongi-do (Korea); Choi, Ja-Young; Hong, Sung Hwan; Kim, Na Ra [Seoul National University College of Medicine, Department of Radiology, Seoul (Korea); Kim, Ki-Jeong; Chung, Sang-Ki; Kim, Hyun-Jib [Seoul National University Bundang Hospital, Department of Neurosurgery, Gyeongi-Do (Korea)

    2008-02-15

    The purpose of our study is to evaluate imaging features suggestive of a conjoined nerve root on routine axial MRI. Two radiologists and two surgeons retrospectively reviewed the MRI of three cases in which a conjoined nerve root was discovered during operation and found three suggestive signs on routine axial MR images: ''corner'' (asymmetric morphology of the anterolateral corner of the dural sac), ''fat crescent'' (intervening extradural fat between the asymmetric dura and the nerve root), and ''parallel'' signs (visualization of the entire parallel course of the nerve root at the disc level). Two radiologists prospectively found these signs during routine MRI interpretation sessions over a period of 6 months. If one or a combination of signs were noted on axial MR images, contiguous axial scans were additionally obtained. Three cases that were previously found during operations were also included. Prevalence and confidence scores for each sign were assessed on axial T1- and T2-weighted images. Twelve patients showed one or a combination of the three signs, 9 had contiguous axial MR scans. Five cases were confirmed by operation. The prevalence of the corner, fat crescent, and parallel signs were 12 out of 12 (100%), 6 out of 12 (50%), and 8 out of 12 (67.7%) on axial T1-weighted images. The overall diagnostic confidence was higher on T1- than on T2-weighted images (P < 0.05). On routine axial L-spine MRI, corner, fat crescent, and parallel signs are suggestive of and assist in the recognition of a conjoined nerve root. (orig.)

  6. Pion Photo- and Electroproduction and the Partially Conserved Axial Current

    International Nuclear Information System (INIS)

    Haberzettl, Helmut

    2000-01-01

    The relevance of the axial current for pion production processes off the nucleon with real or virtual photons is revisited. Employing the hypothesis of a partially conserved axial current (PCAC), it is shown that, when all of the relevant contributions are taken into account, PCAC does not provide any additional constraint for threshold production processes that goes beyond the Goldberger-Treiman relation. In particular, it is shown that pion electroproduction processes at threshold cannot be used to extract any information regarding the weak axial form factor. The relationships found in previous investigations are seen to be an accident of the approximations usually made in this context

  7. Observed Incidence of Uveitis Following Certolizumab Pegol Treatment in Patients With Axial Spondyloarthritis

    NARCIS (Netherlands)

    Rudwaleit, M.; Rosenbaum, J. T.; Landewé, R.; Marzo-Ortega, H.; Sieper, J.; van der Heijde, D.; Davies, O.; Bartz, H.; Hoepken, B.; Nurminen, T.; Deodhar, A.

    2016-01-01

    Axial spondyloarthritis (axial SpA) is characterized by inflammation of the spine and sacroiliac joints and can also affect extraarticular sites, with the most common manifestation being uveitis. Here we report the incidence of uveitis flares in axial SpA patients from the RAPID-axSpA trial,

  8. Carcinoma espinocelular do conduto auditivo externo: estudo por tomografia computadorizada de seis casos Squamous cell carcinoma of the external auditory canal: computed tomography findings in six cases

    Directory of Open Access Journals (Sweden)

    Fábio Mota Gonzalez

    2005-06-01

    Full Text Available OBJETIVO: Analisar a importância da avaliação tomográfica da extensão profunda dos carcinomas espinocelulares do conduto auditivo externo. MATERIAIS E MÉTODOS: Foram realizados exames tomográficos com cortes axiais e coronais com janelas para partes moles e óssea em seis pacientes com carcinoma espinocelular do conduto auditivo externo, com idade variando entre 55 e 71 anos, internados no Hospital Heliópolis, no período entre maio de 1995 e dezembro de 2003. RESULTADOS: Dos seis pacientes, todos apresentavam aumento de partes moles no conduto auditivo externo, cinco (83,3% tinham erosão óssea e invasão da orelha média, quatro (66,7% possuíam comprometimento da mastóide e da glândula parótida, três (50% apresentavam invasão da articulação temporomandibular, dois (33,3% tinham invasão da fossa média, do canal carotídeo e linfonodomegalia júgulo-carotídea alta ipisilateral. CONCLUSÃO: A avaliação da extensão tumoral profunda fornecida pela tomografia computadorizada é importante no estadiamento clínico, possibilitando um planejamento terapêutico mais eficaz.OBJECTIVE: To evaluate the role of computed tomography in the assessment of deep extension of squamous cell carcinoma of the external auditory canal. MATERIALS AND METHODS: In the period between May 1995 and December 2003 six patients with squamous cell carcinoma of the external auditory canal were submitted to computed tomography scan at "Hospital Heliópolis", São Paulo, SP, Brazil, including axial and coronal slices with soft tissue and bone algorithms. RESULTS: Thickening of the soft tissue of the external auditory canal was seen in all patients, bone erosion and invasion of the middle ear in five (83.3%, invasion of the mastoid and parotid gland in four (66.7%, invasion of the temporomandibular joint in three (50%, and invasion of the middle cranial fossa, carotid canal and cervical lymph node enlargement in two (33.3% patients. CONCLUSION: Assessment of

  9. Research on axial thrust of the waterjet pump based on CFD under cavitation conditions

    International Nuclear Information System (INIS)

    Shen, Z H; Pan, Z Y

    2015-01-01

    Based on RANS equations, performance of a contra-rotating axial-flow waterjet pump without hydrodynamic cavitation state had been obtained combined with shear stress transport turbulence model. Its cavitation hydrodynamic performance was calculated and analysed with mixture homogeneous flow cavitation model based on Rayleigh-Plesset equations. The results shows that the cavitation causes axial thrust of waterjet pump to drop. Furthermore, axial thrust and head cavitation characteristic curve is similar. However, the drop point of the axial thrust is postponed by 5.1% comparing with one of head, and the critical point of the axial thrust is postponed by 2.6%

  10. Research on axial thrust of the waterjet pump based on CFD under cavitation conditions

    Science.gov (United States)

    Shen, Z. H.; Pan, Z. Y.

    2015-01-01

    Based on RANS equations, performance of a contra-rotating axial-flow waterjet pump without hydrodynamic cavitation state had been obtained combined with shear stress transport turbulence model. Its cavitation hydrodynamic performance was calculated and analysed with mixture homogeneous flow cavitation model based on Rayleigh-Plesset equations. The results shows that the cavitation causes axial thrust of waterjet pump to drop. Furthermore, axial thrust and head cavitation characteristic curve is similar. However, the drop point of the axial thrust is postponed by 5.1% comparing with one of head, and the critical point of the axial thrust is postponed by 2.6%.

  11. Análise de carcinomas epidermóides por meio de radiografia panorâmica e tomografia computadorizada Analysis of squamous cell carcinomas by means of panoramic radiography and computed tomography

    Directory of Open Access Journals (Sweden)

    Amanda Cáceres PEREIRA

    2001-12-01

    Full Text Available Este trabalho teve como objetivo correlacionar aspectos radiográficos como, localização e extensão do tumor, infiltração óssea e de tecidos moles e destruição das corticais, obtidos nas radiografias panorâmicas com os encontrados nas tomografias computadorizadas (TCs. Os aspectos radiográficos de 48 pacientes com diagnóstico histopatológico de carcinomas epidermóides, localizados em várias regiões do complexo buco-maxilo-facial, foram analisados por 4 radiologistas. As radiografias panorâmicas e as tomografias computadorizadas foram realizadas nos hospitais e clínicas da Universidade de Iowa (EUA, FUNDECTO - USP e Hospital Universitário da Universidade de São Paulo (SP, Brasil. Como resultados, obtivemos a grande limitação da radiografia panorâmica em determinar a localização e extensão do tumor, com delimitações bastante imprecisas da lesão. Já as TCs ofereceram resultados mais direcionados como: invasão do tumor em direção a estruturas moles adjacentes, extensão da destruição óssea, bem como a profundidade da lesão, que foram confirmados com os achados cirúrgicos. Concluímos que a tomografia computadorizada demonstrou ser uma técnica bastante sensível na detecção do comprometimento ósseo e do envolvimento de tecidos moles, proporcionando, assim, o auxílio no diagnóstico e no planejamento do tratamento. No entanto, a radiografia panorâmica foi muito pouco sensível e eficaz, por mostrar apenas margens imprecisas e pouco nítidas da lesão, não avaliando o envolvimento de tecidos moles.The purpose of this work was to compare radiographic findings, such as localization and extension of tumors toward the bone and soft tissues, in panoramic radiography and computed tomography (CT. Four radiologists assessed the radiographic findings of 48 patients with the histopathological diagnosis of squamous cell carcinoma in different sites of the maxillofacial region. Panoramic radiographs and computed

  12. New Sodium Cooled Long-Life Cores with Axially Multi-Driver Regions

    International Nuclear Information System (INIS)

    Hyun, Hae Ri; Hong, Ser Gi

    2014-01-01

    In this concept of long-life core (they are sometimes called B-B (Breed and Burn)), tall blanket is placed above the relatively short driver fuel. In the initial stage of burning, the power by fission is mostly generated in the driver region and it moves into the blanket region. The power and flux distributions that are highly peaked in the axial direction propagates slowly from the driver into the blanket region. This concept of long-life core fully utilizes the breeding of blanket in the fast spectra and it can achieve very high burnup of fuel. In this work, we introduce new sodium cooled longlife cores rating 600MWe (1800MWt). In these cores, the driver regions are heterogeneously placed into blanket region so as to achieve stabilized and less peaked axial power distribution as depletion proceeds. At present, our study is focused on only two axial driver regions but this concept can be easily extended onto the multi-driver region concept. The cores designed in this paper have two axial driver regions so as to have stabilized and less peaked axial power distributions as depletion proceeds. The results of the core design and analyses show that the cores have very long-lives longer than -49EFPYs and high discharge burnup higher than 200GWD/kg. Additionally, we considered a long-life core having no blanket. As expected, it was shown that these cores have stabilized and less peaked axial power distribution as the fuel depletes. However, the study shows that the cores having two driver regions still show high initial peaking of the axial power distributions and the core can be optimized by changing the driver fuel height

  13. Thermal characterization of phacoemulsification probes operated in axial and torsional modes.

    Science.gov (United States)

    Zacharias, Jaime

    2015-01-01

    To analyze temperature increases and identify potential sources of heat generated when sleeved and sleeveless phacoemulsification probes were operated in axial and torsional modes using the Infiniti Vision System with the Ozil torsional handpiece. Phacodynamics Laboratory, Pasteur Ophthalmic Clinic, Santiago, Chile. Experimental study. Two computer-controlled thermal transfer systems were developed to evaluate the contribution of internal metal stress and tip-to-sleeve friction on heat generation during phacoemulsification using axial and torsional ultrasound modalities. Both systems incorporated infrared thermal imaging and used a black-body film to accurately capture temperature measurements. Axial mode was consistently associated with greater temperature increases than torsional mode whether tips were operated with or without sleeves. In tests involving bare tips, axial mode and torsional mode peaked at 51.7°C and 34.2°C, respectively. In an example using sleeved tips in which a 30.0 g load was applied for 1 second, temperatures for axial mode reached 45°C and for torsional mode, 38°C. Friction between the sleeved probe and the incisional wall contributed more significantly to the temperature increase than internal metal stress regardless of the mode used. In all experiments, the temperature increase observed with axial mode was greater than that observed with torsional mode, even when conditions such as power or amplitude and flow rate were varied. Tip-to-sleeve friction was a more dominant source of phaco probe heating than internal metal stress. The temperature increase due to internal metal stress was greater with axial mode than with torsional mode. Dr. Zacharias received research funding from Alcon Laboratories, Inc., to conduct this study. He has no financial or proprietary interest in any material or method mentioned. Copyright © 2015 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  14. The accuracy of axial length measurements in cases of macula-off retinal detachment.

    Science.gov (United States)

    Abou-Shousha, Mohsen; Helaly, Hany Ahmed; Osman, Ihab Mohamed

    2016-04-01

    To assess the accuracy of axial length measurements in cases of macula-off retinal detachment using different methods (optical biometry, A-scan ultrasound, and combined applanation vector-A/B-scan biometry). This prospective clinical study included 100 eyes of 100 patients who underwent vitrectomy alone or phacovitrectomy for macula-off retinal detachment. All patients included signed an informed consent. Preoperative examination of the patients included recording the axial length measurements using optical biometry, A-scan ultrasound, and combined applanation vector-A/B-scan biometry. The mean postoperative IOLMaster axial length after macular reattachment was 26.11 ± 2.91 mm. The mean preoperative IOLMaster axial length with macula-off was 25.32 ± 2.72 mm. The mean preoperative A-scan axial length with macula-off was 25.29 ± 2.80 mm. The mean preoperative vector-A/B-scan axial length with macula-off was 26.03 ± 2.90 mm. The preoperative vector-A/B-scan mean absolute error was 0.59 ± 0.48 D (range, 0.10-2.25 D). Regular methods (optical biometry and A-scan biometry) of measuring the axial length in cases with a detached macula proved to be variable and less accurate. The vector-A/B-scan offered good measurements of the actual axial length in the patients. This was reflected on more accurate postoperative refractive outcome. Copyright © 2016 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.

  15. Calculation of core axial power shapes using alternating conditional expectation algorithm

    International Nuclear Information System (INIS)

    Lee, Eun Ki; Kim, Yong Hee; Cha, Kune Ho; Park, Moon Kyu

    1998-01-01

    We have introduced the alternating conditional expectation (ACE) algorithm in the method of reconstructing 20 node axial power shapes from five level detector powers. The ACE algorithm was used to find the optimal relationships between each plane power and normalized five detector powers. The obtained all optimal transformations had simple forms to be represented with polynomials. The reference axial power shapes and simulated detector powers were drawn out of the 3-dimensional results of Reactor Operation and Control Simulation (ROCS) code for various core states. By the ACE algorithm, we obtained the optimal relationship between dependent variable plane power, y, and independent variable detector powers, {Di, i=1,...,5 without any preprocessing, where a total of ≅3490 data sets per each cycle of YongGwang Nuclear (YGN) Power Plant units 3 and 4 are used. To test the validity and accuracy of the new method, about 21,200 cases of reconstructed axial power shapes are compared to original ROCS axial power shapes, and they are also contrasted with those obtained by Fourier fitting method (FFM). The average error of root mean square (rms), axial peak (DFZ), and axial shape index (DASI) of our new method for total 21204 data cases are 0.81%, 0.51% and 0.00204, while FFM 2.29%, 2.37% and 0.00264, respectively. The evaluation results for the data sets not used in the ACE transformations also show that the accuracy of new method is much better than that of FFM

  16. Optimización de Estatores para Motores Superconductores de Flujo Axial Optimización de Estatores para Motores Superconductores de Flujo Axial

    Directory of Open Access Journals (Sweden)

    Oscar Gerardo Ibarra-Manzano

    2012-02-01

    Full Text Available The development of superconducting electrical machines has been designed primarily to design and build engines with the superconducting magnetic field in radial configuration, as traditional engines, so the design and construction of rotating electrical machines in axial flow configuration has become an alternative for the design and construction of such engines. In this paper we present preliminary calculations for the optimization of the stator of a superconducting motor in axial flow confi guration, based on the equations of general power of the rotary axial flow configuration. It performs the construction, optimization and evaluation of models of stators in geometries of 4, 6 and 8 poles with high-temperature superconducting tapes of Bismuth. The results show the feasibility of the design implemented, which is verified by a significant decrease in the current of superconducting motor operation.El desarrollo de máquinas eléctricas superconductoras ha estado encaminado principalmentea diseñar y construir motores superconductores con el campo magnético en configuración radial, como los motores tradicionales, por lo que el diseño y construcción demáquinas eléctricas rotativas en configuración de flujo axial ha venido a ser una alternativa para el diseño y construcción de este tipo de motores. En el presente trabajo se presentan los cálculos preliminares para la optimización del estator de un motor superconductor en configuración de flujo axial, basados en las ecuaciones generales de potencia de las máquinas eléctricas rotativas en configuración flujo axial ha venido a ser una alternativa para el diseño y construcción, optimización y evaluación de modelos de estatores en geometrías de 4, 6 y 8 polos, con cintas superconductoras de alta temperatura de Bismuto. Los resultados obtenidos muestran la viabilidaddel diseño implementado, lo cual se comprueba por medio de una disminución significativa de la corriente de operaci

  17. CONTRIBUTION OF AXIAL MOTOR IMPAIRMENT TO PHYSICAL INACTIVITY IN PARKINSON'S DISEASE

    Science.gov (United States)

    Bryant, Mon S; Hou, Jyhgong Gabriel; Collins, Robert L; Protas, Elizabeth J

    2015-01-01

    Objective To investigate the relationships between motor symptoms of Parkinson’s disease (PD) and activity limitations in persons with PD. Design/Methods Cross-sectional study of persons with mild to moderate PD (N=90). Associations among axial motor features, limb motor signs, the Physical Activity Scale for Elders (PASE), the ability to perform Activities of Daily Living (ADL) and level of ADL dependency were studied. A composite score of axial motor features included the following UPDRS items: speech, rigidity of the neck, arising from chair, posture, gait and postural stability. A composite score of limb motor signs included the following UPDRS items: tremor at rest of all extremities, action tremor, rigidity of all extremities, finger taps, hand movement, rapid alternating hand movements and foot tapping. Results Axial motor features of PD were significantly correlated with physical inactivity (pphysical inactivity. After controlling for age, gender, disease duration and comorbidity, axial motor features contributed significantly to physical inactivity, decreased ADL and increase in ADL dependency, whereas the limb motor signs did not. Conclusions Axial motor impairment contributed to physical inactivity and decreased ability to perform ADLs in persons with PD. PMID:26368837

  18. Visualization of bonding at an inclusion boundary using axial-shear strain elastography: a feasibility study

    International Nuclear Information System (INIS)

    Thitaikumar, Arun; Krouskop, Thomas A; Garra, Brian S; Ophir, Jonathan

    2007-01-01

    Ultrasound elastography produces strain images of compliant tissues under quasi-static compression. In axial-shear strain elastography, the local axial-shear strain resulting from application of quasi-static axial compression to an inhomogeneous material is imaged. The overall hypothesis of this work is that the pattern of axial-shear strain distribution around the inclusion/background interface is completely determined by the bonding at the interface after normalization for inclusion size and applied strain levels, and that it is feasible to extract certain features from the axial-shear strain elastograms to quantify this pattern. The mechanical model used in this study consisted of a single stiff circular inclusion embedded in a homogeneous softer background. First, we performed a parametric study using finite-element analysis (FEA) (no ultrasound involved) to identify possible features that quantify the pattern of axial-shear strain distribution around an inclusion/background interface. Next, the ability to extract these features from axial-shear strain elastograms, estimated from simulated pre- and post-compression noisy RF data, was investigated. Further, the feasibility of extracting these features from in vivo breast data of benign and malignant tumors was also investigated. It is shown using the FEA study that the pattern of axial-shear strain distribution is determined by the degree of bonding at the inclusion/background interface. The results suggest the feasibility of using normalized features that capture the region of positive and negative axial-shear strain area to quantify the pattern of the axial-shear strain distribution. The simulation results showed that it was feasible to extract the features, as identified in the FEA study, from axial-shear strain elastograms. However, an effort must be made to obtain axial-shear strain elastograms with the highest signal-to-noise ratio (SNR asse ) possible, without compromising the resolution. The in vivo

  19. Organo-axial volvulus of the small intestine: radiological case report and consideration for its mechanism.

    Science.gov (United States)

    Ishiguro, Toshitaka; Hiyama, Takashi; Nasu, Katsuhiro; Akashi, Yoshimasa; Minami, Manabu

    2017-07-01

    Gastrointestinal volvulus is mainly classified into two subtypes, mesentero-axial volvulus and organo-axial volvulus. The detailed imaging findings of organo-axial volvulus of the small intestine have never been reported as far as we know. In this article, we report a case of organo-axial volvulus of the small intestine, focusing on the computed tomography (CT) findings. An 80-year-old man was radiologically diagnosed as having organo-axial volvulus of the terminal ileum and it was confirmed by open surgery without adhesion or any other anatomical abnormalities. CT showed two specific findings, split-bowel sign and rotating-C sign, which we think reflect pathophysiologic features of organo-axial volvulus. We think the pathogenic mechanism of organo-axial volvulus can be explained by the convergence of the reversed-rotational twist following the formation of a twisted but non-obstructive circular loop, even if there is no adhesion. Radiologists should be aware that organo-axial volvulus can occur even in the small intestine, and in the case of small bowel obstruction with single transition point, the two pathophysiologic signs mentioned above must be looked for to diagnose the possibility of organo-axial volvulus.

  20. Rectal contrast-enhanced computed tomography in the diagnosis of acute appendicitis; Tomografia computarizada con contraste rectal en el diagnostico de la apendicitis aguda

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-07-01

    To assess the efficacy and utility of computed tomography (CT) in the diagnosis of appendicitis, and to evaluate the reliability of CT findings in right iliac fossa in the confirmation or exclusion of this diagnosis. Over a one-year period, 152 patients presenting clinical signs of appendicitis underwent CT scans. The images were reviewed by two radiologists who considered whether the appendix was normal or enlarged and the existence of other signs of appendicitis for the purpose of determining whether or not the patient presented appendicitis. The definitive diagnoses were established by surgery or by clinical follow-up. The sensitivity of CT for the diagnosis of appendicitis was 81.8%, the specificity was 95.3%, the positive predictive value was 93.1%, the negative predictive value was 87.2% and the reliability was 89.9%. The signs of appendicitis observed were: appendicoliths (sensitivity 30.3% and specificity 98.8%), fluid collections (sensitivity 19.7%, specificity 96.5%), cecal enlargement (sensitivity 21.2%, specificity 97.7%), inflammation of pericecal fat (sensitivity 72.7%, specificity 90.7%), fascial thickening (sensitivity 48.5%, specificity 91.9%) and an appendix measuring more than 6 mm (sensitivity 78.8%, specificity 94.3%). Adenopathy and free peritoneal fluid were not significantly related to appendicitis. The presence of a normal appendix filled with air or contrast material had an elevated negative predictive value with respect to appendicitis. In 35 of the 94 cases with negative CT scans, the images suggested alternative diagnoses. CT is a highly reliable diagnostic method for appendicitis. The observation of an appendix filled with air or contrast material has an elevated negative predictive value. The presence of appendicoliths has an elevated positive predictive value. (Author) 29 refs.

  1. Epiploic appendicitis and omental infarction. Findings in the ultrasonography and computerized tomography; Apendicitis epiploica e infarto omental. Hallazgos en ecografia y tomografia computarizada

    Energy Technology Data Exchange (ETDEWEB)

    Migule, A.; Ripolles, T.; Martinez, M. J.; Morote, V.; Ruiz, A. [Hospital Universitario Dr. Peset. Valencia (Spain)

    2001-07-01

    Describe the findings in the ultrasonography and computerized tomography (CT) of the omental infarction and epiploic appendicitis. The clinical and radiological findings of the patients diagnosed in our hospital with epiploic appendicitis or omental infarctions between August 1994 and March 2001 were assessed retrospectively. We found a high incidence (42 cases) of these two diseases: 30 patients with diagnosis of epiploic appendicitis and 12 with the diagnosis of omental infarction. Four patients were treated surgically, while the remaining 38 were conservatively, without posterior complications. The ultrasonography and CT images is characteristics. making it possible to make a diagnosis of epiploic appendicitis or omental infarction with certainty. It is not necessary to make a differential diagnosis between the two entities because their prognosis and treatment are similar. Their incidence is much more frequent than that previously published. (Author) 19 refs.

  2. Beyond axial symmetry: An improved class of models for global data

    KAUST Repository

    Castruccio, Stefano

    2014-03-01

    An important class of models for data on a spherical domain, called axially symmetric, assumes stationarity across longitudes but not across latitudes. The main aim of this work is to introduce a new and more flexible class of models by relaxing the assumption of longitudinal stationarity in the context of regularly gridded climate model output. In this investigation, two other related topics are discussed: the lack of fit of an axially symmetric parametric model compared with a non-parametric model and to longitudinally reversible processes, an important subclass of axially symmetric models.

  3. Beyond axial symmetry: An improved class of models for global data

    KAUST Repository

    Castruccio, Stefano; Genton, Marc G.

    2014-01-01

    An important class of models for data on a spherical domain, called axially symmetric, assumes stationarity across longitudes but not across latitudes. The main aim of this work is to introduce a new and more flexible class of models by relaxing the assumption of longitudinal stationarity in the context of regularly gridded climate model output. In this investigation, two other related topics are discussed: the lack of fit of an axially symmetric parametric model compared with a non-parametric model and to longitudinally reversible processes, an important subclass of axially symmetric models.

  4. Neumonía organizada como forma de presentación de una artritis reumatoide

    Directory of Open Access Journals (Sweden)

    Verónica Temprado

    2015-09-01

    Full Text Available La neumonía organizada (NO es una enfermedad pulmonar intersticial que puede asociarse a la artritis reumatoide (AR. Normalmente, la afectación pulmonar se presenta tras años de evolución de las manifestaciones articulares, siendo menos frecuente la aparición concomitante de ambos procesos. Se expone el caso de una paciente de 79 años que presentó tos y disnea junto con inflamación articular y criterios serológicos de AR. La radiografía de tórax (Rx y la tomografía axial computarizada (TAC objetivaron un infiltrado alveolar bibasal con broncograma aéreo. Las manifestaciones pulmonares de una NO motivaron el ingreso y fueron la clave para el diagnóstico final de una AR. La paciente recibió tratamiento corticoideo con excelente respuesta.

  5. Miasis orbital severa causada por Cochliomyia hominivorax en la región andina de Ecuador

    Directory of Open Access Journals (Sweden)

    Juan Dominguez Enríquez

    2016-01-01

    Full Text Available Presentamos el caso de una indígena kichwa de 91 años con miasis orbital destructiva que compromete globo ocular derecho con destrucción de tejido óseo orbital, nasal, etmoidal y del seno frontal, confirmado por tomografía axial computarizada y con reconstrucción ósea tridimensional. Infectada en una zona templada a 2,418 m de altitud en la provincia andina de Imbabura, Ecuador. La paciente se presentó en el Hospital de Cotacachi con una tumoración cavitaria en el globo ocular derecho acompañada de secreción maloliente, supurativa, observando y extrayéndose más de 100 larvas de moscas desde su interior. Estas fueron identificadas como Cochliomyia hominivorax, por la disposición de sus espiráculos respiratorios.

  6. Differential diagnosis of extra-axial intracranial tumours by dynamic spin-echo MRI

    International Nuclear Information System (INIS)

    Joo, Y.G.; Korogi, Y.; Hirai, T.; Sakamoto, Y.; Sumi, M.; Takahashi, M.; Ushio, Y.

    1995-01-01

    Dynamic MRI was performed on 22 patients with extra-axial intracranial tumours. Serial images were obtained every 30 s for 3 min using a spin-echo sequence (TR 200, TE 15 ms) after rapid injection of Gd-DTPA, 0.1 mmol/kg body weight. The contrast medium enhancement ratio (CER) was correlated with the histology of the tumours. Meningiomas and extra-axial metastases showed a sharp rise, then a gradual decline. Although both had a definite early peak of CER, metastases showed a more rapid decline. Neuromas and extra-axial lymphoma showed a slow, steady increase with no peak within 180 s. This study indicates that the CER is helpful in the differentiation of extra-axial tumours. (orig.)

  7. Characterisation of plasmas produced by the "Torche a Injection Axiale"

    NARCIS (Netherlands)

    Jonkers, J.; Selen, L.J.M.; Mullen, van der J.J.A.M.; Regt, de J.M.; Timmermans, E.A.H.; Schram, D.C.

    1996-01-01

    Summary form only given. The Torche a Injection Axiale (TIA), i.e. torch with axial gas injection, was developed by the group of Moisan in 1993. We report on the investigations on two different kind of plasmas created by the TIA: one with helium and the other with argon as main gas. Using absolute

  8. Non-steroidal anti-inflammatory drugs (NSAIDs) for axial spondyloarthritis (ankylosing spondylitis and non-radiographic axial spondyloarthritis)

    NARCIS (Netherlands)

    Kroon, Feline P. B.; van der Burg, Lennart R. A.; Ramiro, Sofia; Landewé, Robert B. M.; Buchbinder, Rachelle; Falzon, Louise; van der Heijde, Désirée

    2015-01-01

    Axial spondyloarthritis (axSpA) comprises ankylosing spondylitis (radiographic axSpA) and non-radiographic (nr-)axSpA and is associated with psoriasis, uveitis and inflammatory bowel disease. Non-steroidal anti-inflammatory drugs (NSAIDs) are recommended as first-line drug treatment. To determine

  9. Optical coherence tomography image in gelatinous drop-like corneal dystrophy: case report Tomografia de coerência óptica na distrofia corneana gelatinosa em gotas: relato de caso

    Directory of Open Access Journals (Sweden)

    Otávio de Azevedo Magalhães

    2012-10-01

    Full Text Available Gelatinous drop-like corneal dystrophy is a rare disorder with few cases described in the present literature. The following report will show how difficult it is to diagnose this disease in early stages. Modern image exams, such as optical coherence tomography helps to diagnose and can be crucial to establish the best treatment. We will present the histopathological changes and clinical features in this unusual dystrophy.A distrofia corneana gelatinosa em gotas é uma desordem rara e pouco descrita em nossa literatura. O caso apresentado demonstra a dificuldade de realizar o diagnóstico nas fases mais iniciais da doença. O uso de modernos exames de imagem, como a tomografia de coerência óptica de segmento anterior, auxilia no diagnóstico e pode ser crucial para definir a melhor conduta terapêutica. Apresentaremos as alterações histopatológicas e as características clínicas desta incomum distrofia.

  10. Axial blanket enrichment optimization of the NPP Krsko fuel

    International Nuclear Information System (INIS)

    Kromar, M.; Kurincic, B.

    2001-01-01

    In this paper optimal axial blanket enrichment of the NPP Krsko fuel is investigated. Since the optimization is dictated by economic categories that can significantly vary in time, two step approach is applied. In the first step simple relationship between the equivalent change in enrichment of axial blankets and central fuel region is established. The relationship is afterwards processed with economic criteria and constraints to obtain optimal axial blanket enrichment. In the analysis realistic NPP Krsko conditions are considered. Except for the fuel enrichment all other fuel characteristics are the same as in the fuel used in the few most recent cycles. A typical reload cycle after the plant power uprate is examined. Analysis has shown that the current blanket enrichment is close to the optimal. Blanket enrichment reduction results in an approximately 100 000 US$ savings per fuel cycle.(author)

  11. Studio del danneggiamento mediante tomografia in luce del sincrotrone: impatto di un cono d’ombra sulla qualità finale delle ricostruzioni

    Directory of Open Access Journals (Sweden)

    Andrea Bernasconi

    2010-07-01

    Full Text Available Un’accurata osservazione della geometria tridimensionale di cricche e difetti è necessaria per lo studio dei meccanismi alla base del processo di danneggiamento. I metodi convenzionali utilizzati a questo scopo sono distruttivi o non possiedono una sufficiente risoluzione. Le tecniche di imaging che utilizzano la luce di sincrotrone, ed in particolare la microtomografia (micro-CT a raggi X, invece, uniscono i vantaggi di una tecnica non distruttiva ad un’elevata risoluzione spaziale e risultano quindi particolarmente interessanti. Un limite all’applicazione di questa tecnica è costituito dalla propensione della cricca a richiudersi una volta rimosso il carico che ha provocato il danneggiamento, superabile attraverso l’impiego di un dispositivo in grado di esercitare un carico di trazione durante l’acquisizione dei dati. Facendo riferimento al set-up sperimentale della linea SYRMEP di Elettra, il sincrotrone di Trieste, e tralasciando per il momento i vincoli legati a pesi e ingombri, è possibile pensare di inserire tra camera di ionizzazione e CCD una macchina per prove di trazione mono-colonna commerciale, in grado di mantenere aperto il difetto per tutta la durata della tomografia. In questo lavoro viene valutato l’impatto di questo vincolo sulla qualità finale delle ricostruzioni.

  12. Computerized axial tomography in traumatic cervical lesions

    International Nuclear Information System (INIS)

    Koyama, Tsunemaro

    1982-01-01

    Although plain computerized axial tomography cannot routinely demonstrate the spinal cord, it does provide excellent visualization of the bony outline of the spinal canal and vertebral column. So it should be reasonable to use this technique in cases of cervical traumatic disorders. In this paper we presented 10 cases of cervical traumatic lesions; 3 atlanto-axial dislocation, 2 cervical canal stenosis, 3 OPLL, 1 intramedullary hematoma and 1 C 2 -neurinoma. In some patients neurologic deficits were induced by cervical trauma. Bony lesions appeared more adequately deliniated than intraspinal lesions, however, in some cases intramedullary changes could also be demonstrated. The use of metrizamide with high resolution CT-scanner could improve the usefullness of this technique. (author)

  13. Ventajas de los motores de flujo axial

    Directory of Open Access Journals (Sweden)

    Alberto M Basanta Otero

    2011-03-01

    Full Text Available Es importante conocer sobre una familia de motores que a diferencia de los convencionales o tradicionales no presentanun flujo rotatorio radial, denominados motores de flujo axial. Dichos motores presentan altos valores de par motriz abajas velocidades, una alta eficiencia y alta densidad de potencia. Este trabajo constituye un breve análisis dealgunos motores de la referencia bibliográfica.  Is important to know about a family of motors that at difference whit the traditional, don't have a rotator radial flux,called, axial flux motors. These motors have high torque for low speed, high efficiency and high power density. Thiswork is a brief analysis of several motors of the bibliographic references.

  14. Golimumab for the treatment of axial spondyloarthritis.

    Science.gov (United States)

    Palazzi, Carlo; D'angelo, Salvatore; Gilio, Michele; Leccese, Pietro; Padula, Angela; Olivieri, Ignazio

    2017-01-01

    Anti-TNF drugs have represented an epochal revolution in the treatment of rheumatoid arthritis and spondyloarthritis. In the field of axial spondyloarthritis, golimumab, a fully human monoclonal anti-TNFα administered subcutaneously every 4 weeks, has shown significant efficacy and good safety in patients with ankylosing spondylitis. More recently, it was also indicated as an effective treatment for patients suffering from non-radiographic axial spondyloarthitits. Areas covered: A systematic literature search was completed, using the largest electronic databases (Medline, Embase and Cochrane), with the aim to review all data concerning the administration of golimumab in patients suffering from axial spondyloartritis. Expert opinion: In the 16-week GO-AHEAD study, golimumab was effective in patients with non-radiographic spondyloarthritis with high levels of CRP and/or positive MRI findings, but not in subjects with both negative CRP and MRI. This finding allows for the addressing the of anti-TNF treatment more specifically. Preliminary data concerning an open-label extension of the GO-AHEAD study outlined the high retention-rate of the drug at 52 weeks. The production of antibodies against golimumab is rare and it seems to exert scarce influence on the drug performances. In conclusion, golimumab appears as a very useful and well tolerated anti-TNF agent.

  15. Passive axial magnetic bearing with Halbach magnetized array in magnetically suspended control moment gyro application

    International Nuclear Information System (INIS)

    Sun Jinji; Ren Yuan; Fang Jiancheng

    2011-01-01

    The paper presents a special configuration of passive axial magnetic bearing with segmented Halbach magnetized array in magnetically suspended control moment gyro (MSCMG). Peculiarity of presented passive axial magnetic bearing is its ability to provide angular stiffness so that it can produce gyro moment when it is used in MSCMG. The MSCMG with this passive axial magnetic bearing can efficiently reduce the power loss when it supplies gyro moment compared with the five degrees of freedom (5-DOF) MSCMG. The characteristics of the suspension force and stiffness of the passive axial magnetic bearing are studied using finite element method (FEM). The performance of the presented passive axial magnetic bearing with Halbach magnetized array is verified by a prototyped MSCMG. - Research highlights: → Passive axial magnetic bearing is used to provide angular stiffness. → Passive axial magnetic bearing is based on repulsion. → Layers Halbach magnetized array realizes higher stiffness per bearing volume. → Passive axial magnetic bearing can provide gyro moment in CMG. → Power loss of MSCMG with PMB does not increase when it provides gyro moment.

  16. Clinical characteristics of importance to outcome in patients with axial spondyloarthritis

    DEFF Research Database (Denmark)

    Andreasen, Rikke Asmussen; Kristensen, Lars Erik; Ellingsen, Torkell

    2017-01-01

    INTRODUCTION: Spondyloarthritis (SpA) is a heterogeneous spectrum of rheumatic diseases with either predominantly axial inflammatory symptoms of the spine and sacroiliac joints or predominantly peripheral arthritis. The two main entities of axial SpA (axSpA) are ankylosing spondylitis or non...

  17. Guided wave propagation as a measure of axial loads in rails

    CSIR Research Space (South Africa)

    Loveday, PW

    2010-03-01

    Full Text Available Guided wave propagation has been proposed as a means to monitor the axial loads in continuously welded railway rails although no practical system has been developed. In this paper, the influence of axial load on the guided wave propagation...

  18. Posterior atlanto-occipital and atlanto-axial area and its surgical interest

    Directory of Open Access Journals (Sweden)

    Newton José Godoy Pimenta

    2014-10-01

    Full Text Available Classic anatomical studies describe two membranes – atlanto-occipital and atlanto-axial in the posterior aspect of the craniocervical region. During many surgical procedures in this area, however, we have not found such membranes. Objective To clarify the anatomical aspects and structures taking part of the posterior atlanto-occipital and atlanto-axial area. Method Analysis of histological cuts of three human fetuses and anatomical studies of 8 adult human cadavers. Results In both atlanto-occipital and atlanto-axial areas, we have observed attachment between suboccipital deep muscles and the spinal cervical dura. However, anatomical description of such attachments could not be found in textbooks of anatomy. Conclusion Our study shows the absence of the classical atlanto-occipital and atlanto-axial membranes; the occipito-C1 and C1-C2 posterior intervals are an open area, allowing aponeurotic attachment among cervical dura mater and posterior cervical muscles.

  19. Amphiregulin Antibody and Reduction of Axial Elongation in Experimental Myopia

    Directory of Open Access Journals (Sweden)

    Wen Jun Jiang

    2017-03-01

    Full Text Available To examine the mechanism of ocular axial elongation in myopia, guinea pigs (age: 2–3 weeks which either underwent unilateral or bilateral lens-induced myopization (group 1 or which were primarily myopic at baseline (group 2 received unilateral intraocular injections of amphiregulin antibody (doses: 5, 10, or 15 μg three times in intervals of 9 days. A third group of emmetropic guinea pigs got intraocular unilateral injections of amphiregulin (doses: 0.25, 0.50 or 1.00 ng, respectively. In each group, the contralateral eyes received intraocular injections of Ringer's solution. In intra-animal inter-eye comparison and intra-eye follow-up comparison in groups 1 and 2, the study eyes as compared to the contralateral eyes showed a dose-dependent reduction in axial elongation. In group 3, study eyes and control eyes did not differ significantly in axial elongation. Immunohistochemistry revealed amphiregulin labelling at the retinal pigment epithelium in eyes with lens-induced myopization and Ringer's solution injection, but not in eyes with amphiregulin antibody injection. Intraocular injections of amphiregulin-antibody led to a reduction of lens-induced axial myopic elongation and of the physiological eye enlargement in young guinea pigs. In contrast, intraocularly injected amphiregulin in a dose of ≤1 ng did not show a significant effect. Amphiregulin may be one of several essential molecular factors for axial elongation.

  20. A note on axial symmetries

    International Nuclear Information System (INIS)

    Beetle, Christopher; Wilder, Shawn

    2015-01-01

    This note describes how to characterize and normalize an axial Killing field on a general Riemannian geometry or four-dimensional Lorentzian geometry. No global assumptions are necessary, such as that the orbits of the Killing field all have period 2π. Rather, any Killing field that vanishes at at least one point necessarily has the expected global properties. (note)

  1. Computed Tomography of the diabetic kidney; La Tomografia Computerizzata nello studio del rene diabetico

    Energy Technology Data Exchange (ETDEWEB)

    Angelelli, G.; Stabile Ianora, A.A.; Scardapane, A.; Rotondo, A. [Bari Univ., Bari (Italy). Ist. di Radiologia

    2000-02-01

    The purpose of this work is to investigate whether any morphometric or densitometric are detectable in the kidneys of type 2 diabetic patients. 40 diabetic patients were examined and of 20 non-diabetics (the control group) were submitted to triphasic helical CT for different abdominal conditions. The type 2 diabetic patients were 23 men and 17 women, mean age 62 years, while the nondiabetic controls were 12 men and 8 women, mean age 58 years. All the CT images were analyzed using the Multiplanar Reconstruction (MPR) software. It was evaluated morphometric features, such as the presence of parenchymal or vascular calcifications, axial and coronal renal diameters, coronal renal area, and cortico medullary ratio, and densitometric and functional features, such as unenhanced renal density, cortical and medullary density in the arterial phase, parenchymal density in the nephrographic phase, and contrast elimination. It was also compared the results in the subgroups of patients with those in the controls. Both renal diameters on axial sections and cortical density in the arterial phase were significantly lower in the nephropathic group (p<0.05) than in non-nephropathic patients and control. The patients with shorter duration of their diabetes had significantly greater axial diameters (p<0.05); a longer-standing disease correlated significantly (p<0.05) with smaller axial diameters of kidneys and lower cortical density in the arterial phase. Renal diameters on axial and coronal sections and cortical density in the arterial phase can be useful indices of early nephropathy in diabetic patients. Further studies are warranted to make these findings suitable for use in clinical practice. [Italian] In questo articolo sono presentate le eventuali alterazioni tomodensitometriche a livello renale di pazienti affetti da diabete mellito di tipo 2. Si sono valutate retrospettivamente le immagini TC di 40 soggetti affetti da diabete di tipo 2 (23 maschi, 17 femmine, eta' media 62

  2. Axial power deviation control strategy and computer simulation for Daya Bay Nuclear Power Station

    International Nuclear Information System (INIS)

    Liao Yehong; Zhou Xiaoling, Xiao Min

    2004-01-01

    Daya Bay Nuclear Power Station has very tight operation diagram especially at its right side. Therefore the successful control of axial power deviation for PWR is crucial to nuclear safety. After analyzing various core characters' effect on axial power distribution, several axial power deviation control strategies has been proposed to comply with different power varying operation scenario. Application and computer simulation of the strategies has shown that our prediction of axial power deviation evolution are comparable to the measurement values, and that our control strategies are effective. Engineering experience shows that the application of our methodology can predict accurately the transient of axial power deviation, and therefore has become a useful tool for reactor operation and safety control. This paper presents the axial power control characteristics, reactor operation strategy research, computer simulation, and comparison to measurement results in Daya Bay Nuclear Power Station. (author)

  3. Theorem on axially symmetric gravitational vacuum configurations

    Energy Technology Data Exchange (ETDEWEB)

    Papadopoulos, A; Le Denmat, G [Paris-6 Univ., 75 (France). Inst. Henri Poincare

    1977-01-24

    A theorem is proved which asserts the non-existence of axially symmetric gravitational vacuum configurations with non-stationary rotation only. The eventual consequences in black-hole physics are suggested.

  4. Tunable axial gauge fields in engineered Weyl semimetals: semiclassical analysis and optical lattice implementations

    Science.gov (United States)

    Roy, Sthitadhi; Kolodrubetz, Michael; Goldman, Nathan; Grushin, Adolfo G.

    2018-04-01

    In this work, we describe a toolbox to realize and probe synthetic axial gauge fields in engineered Weyl semimetals. These synthetic electromagnetic fields, which are sensitive to the chirality associated with Weyl nodes, emerge due to spatially and temporally dependent shifts of the corresponding Weyl momenta. First, we introduce two realistic models, inspired by recent cold-atom developments, which are particularly suitable for the exploration of these synthetic axial gauge fields. Second, we describe how to realize and measure the effects of such axial fields through center-of-mass observables, based on semiclassical equations of motion and exact numerical simulations. In particular, we suggest realistic protocols to reveal an axial Hall response due to the axial electric field \

  5. Axial-Centrifugal Compressor Program

    Science.gov (United States)

    1975-10-01

    Assembly . .. . .... ..... 33 5 Tie Bolt...... .. .. .. .. . *.. .. .. .. .. .. ... 34 6 Axial Compressor Rotor Assembly Runouts . . .. . 34 7 CCV Blow...1.796 Impeller Slip Factor ’Ce2/U 2 ) .91 Impeller Wheel Speed ft/sec 1992.2 Impellet ’.ip Radius in. 3.780 Blade Tip Metal Angle- deg 0 Numbec of Blades...test item to the next Phase V component test. The test vehicle final balance levels and rotor runouts were normal at teardown, and no rubsI were

  6. Improvement of axial power distribution synthesis methodology in CPC

    International Nuclear Information System (INIS)

    Kim, H. H.; Gee, S. G.;; Kim, Y. B.; In, W. K.

    2003-01-01

    The capability of axial power distribution synthesis in CPC plays an important role in determining the DNBR and LPD trip caused by CPC. The axial power distribution is synthesized using the cubic spline function based on the three excore detector signals. The axial power distributions are categorized into 8 function sets and each sets are stored as pre-calculated values in CPC to save the calculation time. In this study, the additional function sets, the real break-point function sets and the polynomial function are suggested to evaluate the possibility of improving the synthesis capability in CPC. In addition, RMS errors are compared and evaluated for each synthesis method. As a result, it was confirmed that the function sets stored in CPC were not optimal. The analysis result showed that RMS error could be reduced by selecting the proper function sets suggested in this study

  7. Constitutive relations describing creep deformation for multi-axial time-dependent stress states

    Science.gov (United States)

    McCartney, L. N.

    1981-02-01

    A THEORY of primary and secondary creep deformation in metals is presented, which is based upon the concept of tensor internal state variables and the principles of continuum mechanics and thermodynamics. The theory is able to account for both multi-axial and time-dependent stress and strain states. The wellknown concepts of elastic, anelastic and plastic strains follow naturally from the theory. Homogeneous stress states are considered in detail and a simplified theory is derived by linearizing with respect to the internal state variables. It is demonstrated that the model can be developed in such a way that multi-axial constant-stress creep data can be presented as a single relationship between an equivalent stress and an equivalent strain. It is shown how the theory may be used to describe the multi-axial deformation of metals which are subjected to constant stress states. The multi-axial strain response to a general cyclic stress state is calculated. For uni-axial stress states, square-wave loading and a thermal fatigue stress cycle are analysed.

  8. Design, Test, and Evaluation of a Transonic Axial Compressor Rotor with Splitter Blades

    Science.gov (United States)

    2013-09-01

    INTRODUCTION A. MOTIVATION Over the course of turbomachinery history splitter vanes have been used extensively in centrifugal compressors . Axial...TEST, AND EVALUATION OF A TRANSONIC AXIAL COMPRESSOR ROTOR WITH SPLITTER BLADES by Scott Drayton September 2013 Dissertation Co...AXIAL COMPRESSOR ROTOR WITH SPLITTER BLADES 5. FUNDING NUMBERS 6. AUTHOR(S) Scott Drayton 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES

  9. Spectral analysis in thin tubes with axial heterogeneities

    KAUST Repository

    Ferreira, Rita; Mascarenhas, M. Luí sa; Piatnitski, Andrey

    2015-01-01

    In this paper, we present the 3D-1D asymptotic analysis of the Dirichlet spectral problem associated with an elliptic operator with axial periodic heterogeneities. We extend to the 3D-1D case previous 3D-2D results (see [10]) and we analyze the special case where the scale of thickness is much smaller than the scale of the heterogeneities and the planar coefficient has a unique global minimum in the periodic cell. These results are of great relevance in the comprehension of the wave propagation in nanowires showing axial heterogeneities (see [17]).

  10. Rotating stall simulation for axial and centrifugal compressors

    Science.gov (United States)

    Halawa, Taher; Gadala, Mohamed S.

    2017-05-01

    This study presents a numerical simulation of the rotating stall phenomenon in axial and centrifugal compressors with detailed descriptions of stall precursors and its development with time. Results showed that the vaneless region of the centrifugal compressor is the most critical location affected by stall. It was found that the tip leakage flow and the back flow impingement are the main cause of the stall development at the impeller exit area for centrifugal compressors. The results of the axial compressor simulations indicated that the early separated flow combined with the tip leakage flow can block the impeller passages during stall.

  11. Interconnection between several eye biomechanical and biometric parameters in children with axial and refractive mild myopia

    Directory of Open Access Journals (Sweden)

    T. Ye. Tsybulskaya

    2016-08-01

    Full Text Available Aim – to study the relationship of biometric and biomechanical indicators of corneoscleral capsule of the eye in children with axial and refractive mild myopia. Materials and methods. Axial myopia was diagnosed in 32 children (64 eyes, refractive myopia – 18 (36 eyes. The control group – 16 children without ophthalmic diseases (32 eyes. Eye examination: visometry, automated refractometry, biomicroscopy, ophthalmoscopy, determination of the axial length of the eyeball and corneal hysteresis. Results. Significant differences were determined in the indicators of dioptric power of the cornea: 42.2 dpt in patients with axial and 44.7 dpt with refractive myopia (p<0.05, and also difference between patients with refractive myopia and the control group, in which the diopter power of cornea was 42.6 (p<0.05. There are also significant differences in the indicators of the axial length of eyes between axial and refractive myopia – 24.5±0.64 mm and 23.1±0.43 mm (p<0.05. Significant difference with the control group in the axial length marked only in eyes with axial myopia 22.7±0.33 mm and 24.5±0.64 mm, respectively (p<0.05. Corneal hysteresis determined significantly reduced on eyes with both the axial and refractive myopia, which was significantly lower than in the indicators of emmetropic eyes of the control group 13.7 (p<0.05. Corneal hysteresis is inversely related to the axial length of the eyeball: in patients with axial myopia r -0.32, p<0.05; with refractive myopia r -0.36, p<0.05. Сorrelation between diopter power of cornea and axial length of the eyeball: r -0.53, р<0.05 in eyes with axial myopia and r -0.42, p<0.05 refractive myopia. Comparative analysis showed no significant differences between the corneal hysteresis, the axial length of the eye and the spherical component of myopia. Conclusions. In patients with axial and refractive mild myopia corneal hysteresis is reduced on average in 1.2 and 1.1 times, in comparison with

  12. Breast tumor classification using axial shear strain elastography: a feasibility study

    International Nuclear Information System (INIS)

    Thitaikumar, Arun; Ophir, Jonathan; Mobbs, Louise M; Kraemer-Chant, Christina M; Garra, Brian S

    2008-01-01

    Recently, the feasibility of visualizing the characteristics of bonding at an inclusion-background boundary using axial-shear strain elastography was demonstrated. In this paper, we report a feasibility study on the utility of the axial-shear strain elastograms in the classification of in vivo breast tumor as being benign or malignant. The study was performed using data sets obtained from 15 benign and 15 malignant cases that were biopsy proven. A total of three independent observers were trained, and their services were utilized for the study. A total of 9 cases were used as training set and the remaining cases were used as testing set. The feature from the axial-shear strain elastogram, namely, the area of the axial-shear region, was extracted by the observers. The observers also outlined the tumor area on the corresponding sonogram, which was used to normalize the area of the axial-shear strain region. There are several observations that can be drawn from the results. First, the result indicates that the observers consistently (∼82% of the cases) noticed the characteristic pattern of the axial-shear strain distribution data as predicted in the previous simulation studies, i.e. alternating regions of positive and negative axial-shear strain values around the tumor-background interface. Second, the analysis of the result suggests that in approximately 57% of the cases in which the observers did not visualize tumor in the sonogram, the elastograms helped them to locate the tumor. Finally, the analysis of the result suggests that for the discriminant feature value of 0.46, the number of unnecessary biopsies could be reduced by 56.3% without compromising on sensitivity and on negative predictive value (NPV). Based on the results in this study, feature values greater than 0.75 appear to be indicative of malignancy, while values less than 0.46 to be indicative of benignity. Feature values between 0.46 and 0.75 may result in an overlap between benign and malignant

  13. Utility of axial images in an early Alzheimer disease diagnosis support system (VSRAD)

    International Nuclear Information System (INIS)

    Goto, Masami; Aoki, Shigeki; Abe, Osamu

    2006-01-01

    In recent years, voxel-based morphometry (VBM) has become a popular tool for the early diagnosis of Alzheimer disease. The Voxel-Based Specific Regional Analysis System for Alzheimer's Disease (VSRAD), a VBM system that uses MRI, has been reported to be clinically useful. The able-bodied person database (DB) of VSRAD, which employs sagittal plane imaging, is not suitable for analysis by axial plane imaging. However, axial plane imaging is useful for avoiding motion artifacts from the eyeball. Therefore, we created an able-bodied person DB by axial plane imaging and examined its utility. We also analyzed groups of able-bodied persons and persons with dementia by axial plane imaging and reviewed the validity. After using the DB of axial plane imaging, the Z-score of the intrahippocampal region improved by 8 in 13 instances. In all brains, the Z-score improved by 13 in all instances. (author)

  14. [Utility of axial images in an early Alzheimer disease diagnosis support system (VSRAD)].

    Science.gov (United States)

    Goto, Masami; Aoki, Shigeki; Abe, Osamu; Masumoto, Tomohiko; Watanabe, Yasushi; Satake, Yoshiroh; Nishida, Katsuji; Ino, Kenji; Yano, Keiichi; Iida, Kyohhito; Mima, Kazuo; Ohtomo, Kuni

    2006-09-20

    In recent years, voxel-based morphometry (VBM) has become a popular tool for the early diagnosis of Alzheimer disease. The Voxel-Based Specific Regional Analysis System for Alzheimer's Disease (VSRAD), a VBM system that uses MRI, has been reported to be clinically useful. The able-bodied person database (DB) of VSRAD, which employs sagittal plane imaging, is not suitable for analysis by axial plane imaging. However, axial plane imaging is useful for avoiding motion artifacts from the eyeball. Therefore, we created an able-bodied person DB by axial plane imaging and examined its utility. We also analyzed groups of able-bodied persons and persons with dementia by axial plane imaging and reviewed the validity. After using the DB of axial plane imaging, the Z-score of the intrahippocampal region improved by 8 in 13 instances. In all brains, the Z-score improved by 13 in all instances.

  15. Aryabhala and Axial Rotation of Earth

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 11; Issue 3. Aryabhata and Axial Rotation of Earth - Khagola (The Celestial Sphere). Amartya Kumar Dutta. General Article Volume 11 Issue 3 March 2006 pp 51-68. Fulltext. Click here to view fulltext PDF. Permanent link:

  16. Axial Ge/Si nanowire heterostructure tunnel FETs.

    Energy Technology Data Exchange (ETDEWEB)

    Dayeh, Shadi A. (Los Alamos National Laboratory); Gin, Aaron V.; Huang, Jian Yu; Picraux, Samuel Thomas (Los Alamos National Laboratory)

    2010-03-01

    Axial Ge/Si heterostructure nanowires (NWs) allow energy band-edge engineering along the axis of the NW, which is the charge transport direction, and the realization of asymmetric devices for novel device architectures. This work reports on two significant advances in the area of heterostructure NWs and tunnel FETs: (i) the realization of 100% compositionally modulated Si/Ge axial heterostructure NWs with lengths suitable for device fabrication and (ii) the design and implementation of Schottky barrier tunnel FETs on these NWs for high-on currents and suppressed ambipolar behavior. Initial prototype devices with 10 nm PECVD SiN{sub x} gate dielectric resulted in a very high current drive in excess of 100 {micro}A/{micro}m (I/{pi}D) and 10{sup 5} I{sub on}/I{sub off} ratios. Prior work on the synthesis of Ge/Si axial NW heterostructures through the VLS mechanism have resulted in axial Si/Si{sub 1-x}Ge{sub x} NW heterostructures with x{sub max} {approx} 0.3, and more recently 100% composition modulation was achieved with a solid growth catalyst. In this latter case, the thickness of the heterostructure cannot exceed few atomic layers due to the slow axial growth rate and concurrent radial deposition on the NW sidewalls leading to a mixture of axial and radial deposition, which imposes a big challenge for fabricating useful devices form these NWs in the near future. Here, we report the VLS growth of 100% doping and composition modulated axial Ge/Si heterostructure NWs with lengths appropriate for device fabrication by devising a growth procedure that eliminates Au diffusion on the NW sidewalls and minimizes random kinking in the heterostructure NWs as deduced from detailed microscopy analysis. Fig. 1 a shows a cross-sectional SEM image of epitaxial Ge/Si axial NW heterostructures grown on a Ge(111) surface. The interface abruptness in these Ge/Si heterostructure NWs is of the order of the NW diameter. Some of these NWs develop a crystallographic kink that is {approx

  17. Assessment of the impact of modeling axial compression on PET image reconstruction.

    Science.gov (United States)

    Belzunce, Martin A; Reader, Andrew J

    2017-10-01

    To comprehensively evaluate both the acceleration and image-quality impacts of axial compression and its degree of modeling in fully 3D PET image reconstruction. Despite being used since the very dawn of 3D PET reconstruction, there are still no extensive studies on the impact of axial compression and its degree of modeling during reconstruction on the end-point reconstructed image quality. In this work, an evaluation of the impact of axial compression on the image quality is performed by extensively simulating data with span values from 1 to 121. In addition, two methods for modeling the axial compression in the reconstruction were evaluated. The first method models the axial compression in the system matrix, while the second method uses an unmatched projector/backprojector, where the axial compression is modeled only in the forward projector. The different system matrices were analyzed by computing their singular values and the point response functions for small subregions of the FOV. The two methods were evaluated with simulated and real data for the Biograph mMR scanner. For the simulated data, the axial compression with span values lower than 7 did not show a decrease in the contrast of the reconstructed images. For span 11, the standard sinogram size of the mMR scanner, losses of contrast in the range of 5-10 percentage points were observed when measured for a hot lesion. For higher span values, the spatial resolution was degraded considerably. However, impressively, for all span values of 21 and lower, modeling the axial compression in the system matrix compensated for the spatial resolution degradation and obtained similar contrast values as the span 1 reconstructions. Such approaches have the same processing times as span 1 reconstructions, but they permit significant reduction in storage requirements for the fully 3D sinograms. For higher span values, the system has a large condition number and it is therefore difficult to recover accurately the higher

  18. Production of low axial energy spread ion beams with multicusp sources

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yung -Hee Y. [Univ. of California, Berkeley, CA (United States)

    1998-05-01

    Multicusp ion sources are capable of producing ions with low axial energy spread which are necessary in applications such as: ion projection lithography (IPL) and focused ion beams for the next generation lithographic tools and nuclear science experiments such as radioactive ion beam production. The axial ion energy spread for multicusp source is approximately 6 eV which is too large for IPL and radioactive ion beam applications. The addition of a magnetic filter which consists of a pair of permanent magnets to the multicusp source reduces the energy spread considerably. The reduction is due to the improvement in the uniformity of the axial plasma potential distribution in the discharge region. Axial ion energy spread of the filament driven ion source has been measured using three different techniques. In all cases, it was found to be less than 2 eV. Energy spread of the radio frequency (RF) driven source has also been explored, and it was found to be less than 3 eV with the proper RF-shielding. A new multicusp source configuration has been designed and constructed to further reduce the energy spread. To achieve a more uniform axial plasma potential distribution, a cylindrical magnetic filter has been designed and constructed for a 2-cm-diameter source. This new source configuration, the co-axial source, is new in its kind. The energy spread in this source has been measured to be a record low of 0.6 eV. Because of the novelty of this device, some plasma parameters inside the source have been studied. Langmuir probe has been used to measure the plasma potential, the electron temperature and the density distribution.

  19. Production of low axial energy spread ion beams with multicusp sources

    International Nuclear Information System (INIS)

    Lee, Y.H.Y.

    1998-05-01

    Multicusp ion sources are capable of producing ions with low axial energy spread which are necessary in applications such as: ion projection lithography (IPL) and focused ion beams for the next generation lithographic tools and nuclear science experiments such as radioactive ion beam production. The axial ion energy spread for multicusp source is approximately 6 eV which is too large for IPL and radioactive ion beam applications. The addition of a magnetic filter which consists of a pair of permanent magnets to the multicusp source reduces the energy spread considerably. The reduction is due to the improvement in the uniformity of the axial plasma potential distribution in the discharge region. Axial ion energy spread of the filament driven ion source has been measured using three different techniques. In all cases, it was found to be less than 2 eV. Energy spread of the radio frequency (RF) driven source has also been explored, and it was found to be less than 3 eV with the proper RF-shielding. A new multicusp source configuration has been designed and constructed to further reduce the energy spread. To achieve a more uniform axial plasma potential distribution, a cylindrical magnetic filter has been designed and constructed for a 2-cm-diameter source. This new source configuration, the co-axial source, is new in its kind. The energy spread in this source has been measured to be a record low of 0.6 eV. Because of the novelty of this device, some plasma parameters inside the source have been studied. Langmuir probe has been used to measure the plasma potential, the electron temperature and the density distribution

  20. Lesões traumáticas do tórax. Aspectos na tomografia computadorizada

    Directory of Open Access Journals (Sweden)

    Alessandro Severo Alves de Melo

    2004-09-01

    Full Text Available RESUMO: O trauma representa, no mundo actual, uma das principais causas de morte, e o acometimento torácico significa um importante agravamento nas vítimas de trauma multi-sistémico. Neste trabalho foram estudados os aspectos tomográficos de 200 pacientes com trauma torácico. As lesões pulmonares predominaram, tendo sido observadas em 192 casos (96%, manifestadas sob a forma de contusões em 178 casos (89%, atelectasias em 41 casos (20,5%, lacerações em 15 casos (7,5% e hematomas em 6 casos (3%. Lesões pleurais foram demonstradas em 140 casos (70%, dos quais em 121 casos (60,5% havia hemotórax e em 84 casos (42% pneumotórax. As lesões mediastínicas estiveram presentes em 28 casos (14%, com pneumomediastino em 18 (9%, hematoma mediastínico em 7 casos (3,5%, hemopericárdio em 4 (2% e lesões da aorta em 3 (1,5%. As lesões diafragmáticas foram observadas em 8 pacientes (4%. O enfisema de partes moles foi demonstrado em 36 casos (18%.REV PORT PNEUMOL 2004; X (5: 393-403 ABSTRACT: Trauma is nowadays one of the most common causes of death and traumatic thoracic lesions are important agravant to trauma patients. In this work the aspects of computed tomography from 200 cases of thoracic trauma were studied. Lung lesions predominated, found in 192 cases (96%, manifested as contusions in 178 cases (89%, atelectasis in 41 cases (20,5%, lacerations in 15 cases (7,5% and hematomas in 6 cases (3%. Pleural lesions were showed in 140 cases (70%, among them in 121 cases (60,5% there were hemothorax and in 84 cases (42%, pneumothorax. Mediastinal lesions were observed in 28 cases (14%, with pneumomediastinum in 18 cases (9%, mediastinal hematoma in 7 cases (3,5%, hemopericardium in 4 cases (2% and aortic lesions in 3 cases (1,5%. Diaphragmatic rupture was seen in 8 pacients (4%. Soft tissue emphysema was demonstrated in 36 cases (18%.REV PORT PNEUMOL 2004; X (5: 393-403 Palavras-chave: Tórax, tomografia computadorizada, trauma torácico, Key

  1. Bifunctional organocatalysts for the asymmetric synthesis of axially chiral benzamides

    Directory of Open Access Journals (Sweden)

    Ryota Miyaji

    2017-08-01

    Full Text Available Bifunctional organocatalysts bearing amino and urea functional groups in a chiral molecular skeleton were applied to the enantioselective synthesis of axially chiral benzamides via aromatic electrophilic bromination. The results demonstrate the versatility of bifunctional organocatalysts for the enantioselective construction of axially chiral compounds. Moderate to good enantioselectivities were afforded with a range of benzamide substrates. Mechanistic investigations were also carried out.

  2. Multidetector CT enteroclysis: comparison of the reading performance for axial and coronal views

    International Nuclear Information System (INIS)

    Schmidt, Sabine; Chalaron, Marc; Schnyder, Pierre; Denys, Alban; Chevallier, Patrick; Bessoud, Bertrand; Verdun, Francis R.; Frascarolo, Philippe

    2005-01-01

    The purpose of this study was to compare the diagnostic performance of axial and coronal views in multidetector CT enteroclysis (MDCTE). We retrospectively evaluated 48 patients with pathological correlation investigated by MDCTE for small bowel disorders. After nasojejunal administration of 2 l of 5% methylcellulose axial arterial and venous acquisition of MDCTE was followed by coronal reconstructions using equal slice thicknesses of 2.5 mm with 2 mm increments. Spatial resolution of both planes was evaluated by phantom. Three radiologists independently read axial and coronal images concerning 12 pathological features. The interobserver agreement and time of reading was calculated. Sensitivity and specificity resulted from comparison with histopathology (n=39) or follow-up (n=9). Phantom study revealed higher spatial resolution for axial than coronal views, whatever reconstruction interval was used. However, spatial frequency always remained high. Most pathological signs, such as bowel wall thickening (BWT), bowel wall enhancement (BWE) and intraperitoneal fluid (IPF), showed better interobserver agreement on axial than coronal views (BWT: 0.61 vs. 0.44; BWE: 0.56 vs. 0.5; IPF:0.53 vs. 0.43). The Wilcoxon signed-rank test revealed significantly higher sensitivity for axial than coronal views (P=0.0453); the time of reading was significantly shorter for the latter (P=0.0146). The diagnostic value of axial slices is superior to coronal reconstructions despite the reduced data volume and display of the physiological course of bowel loops on the coronal plane. (orig.)

  3. Imaging results and TOF studies with axial PET detectors

    CERN Document Server

    Joram, Christian

    2013-01-01

    We have developed a fully operational PET demonstrator setup which allows true 3D reconstruction of the 511 keV photons and therefore leads to practically parallax free images. The AX-PET concept is based on thin 100 mm long scintillation crystals (LYSO), axially oriented and arranged in layers around the held of view. Layers of wavelength shifting plastic strips mounted in between the crystal layers give the axial coordinate. Both crystals and WLS strips are individually read out by G-APD (SiPM) photodetectors. The Fully scalable concept overcomes the dilemma of sensitivity versus spatial resolution which is inherent to classical PET designs. A demonstrator set-up based on two axial modules was exhaustively characterized using point-like sources, phantoms filled with radiotracer and finally rats and a mouse. The results entirely meet the performance expectations ( <2 mm FWHM in all three coordinates over the complete held of view) and also demonstrated the ability to include Compton interactions (inter-cr...

  4. Bifurcation and chaos of an axially accelerating viscoelastic beam

    International Nuclear Information System (INIS)

    Yang Xiaodong; Chen Liqun

    2005-01-01

    This paper investigates bifurcation and chaos of an axially accelerating viscoelastic beam. The Kelvin-Voigt model is adopted to constitute the material of the beam. Lagrangian strain is used to account for the beam's geometric nonlinearity. The nonlinear partial-differential equation governing transverse motion of the beam is derived from the Newton second law. The Galerkin method is applied to truncate the governing equation into a set of ordinary differential equations. By use of the Poincare map, the dynamical behavior is identified based on the numerical solutions of the ordinary differential equations. The bifurcation diagrams are presented in the case that the mean axial speed, the amplitude of speed fluctuation and the dynamic viscoelasticity is respectively varied while other parameters are fixed. The Lyapunov exponent is calculated to identify chaos. From numerical simulations, it is indicated that the periodic, quasi-periodic and chaotic motions occur in the transverse vibrations of the axially accelerating viscoelastic beam

  5. Thermocapillary Convection in Floating Zone with Axial Magnetic Fields

    Science.gov (United States)

    Liang, Ruquan; Yang, Shuo; Li, Jizhao

    2014-02-01

    Numerical simulations on the effects of axial magnetic fields on the thermocapillary convection in a liquid bridge of silicone-oil-based ferrofluid under zero gravity have been conducted. The Navier-Stokes equations coupled with the energy conservation equation are solved on a staggered grid, and the mass conserving level set approach is used to capture the free surface deformation of the liquid bridge. The obvious effects of the magnetic fields on the flow pattern as well as the velocity and temperature distributions in the liquid bridge can be detected. The axial magnetic fields suppress the thermocapillary convection and a stagnant flow zone is formed between the circulating flow and the symmetric axis as the magnetic fields increase. The axial magnetic fields affect not only the velocity level inside the liquid bridge but also the velocity level on the free surface. The temperature contours near the free surface illustrates conduction-type temperature profiles at moderate strength fields.

  6. Axial shuffling fuel-management schemes for 1.2% SEU in CANDU

    International Nuclear Information System (INIS)

    Younis, M.H.; Boczar, P.G.

    1989-11-01

    The use of slightly enriched uranium (SEU) in CANDU (CANada Deuterium Uranium) requires a different fuel-management strategy than that usually employed with natural uranium fuel. Axial shuffling is a fuel-management strategy in which some or all of the fuel bundles are removed from the channel, rearranged, and reinserted into the same channel, along with fresh fuel. An axial shuffling scheme has been devised for 1.2% SEU which results in excellent power profiles, from the perspectives of both good axial flattening and power histories. With the CANFLEX (CANdu FLEXible fuelling) advanced fuel bundle, fuel rating can be reduced to below 40kW/m, with consequent safety benefits

  7. Critical Axial Load

    Directory of Open Access Journals (Sweden)

    Walt Wells

    2008-01-01

    Full Text Available Our objective in this paper is to solve a second order differential equation for a long, simply supported column member subjected to a lateral axial load using Heun's numerical method. We will use the solution to find the critical load at which the column member will fail due to buckling. We will calculate this load using Euler's derived analytical approach for an exact solution, as well as Euler's Numerical Method. We will then compare the three calculated values to see how much they deviate from one another. During the critical load calculation, it will be necessary to calculate the moment of inertia for the column member.

  8. Helical axial injection concept for cyclotrons

    Energy Technology Data Exchange (ETDEWEB)

    Hudson, E.D.

    1981-01-01

    A concept for an external beam injection system using a helical beam path centered on the cyclotron axis is described. This system could be used to couple two accelerator stages, with or without intermediate stripping, in cases where conventional axial injection or radial injection are not practical.

  9. Helical axial injection concept for cyclotrons

    International Nuclear Information System (INIS)

    Hudson, E.D.

    1981-01-01

    A concept for an external beam injection system using a helical beam path centered on the cyclotron axis is described. This system could be used to couple two accelerator stages, with or without intermediate stripping, in cases where conventional axial injection or radial injection are not practical

  10. BPHZL-subtraction scheme and axial gauges

    Energy Technology Data Exchange (ETDEWEB)

    Kreuzer, M.; Rebhan, A.; Schweda, M.; Piguet, O.

    1986-03-27

    The application of the BPHZL subtraction scheme to Yang-Mills theories in axial gauges is presented. In the auxillary mass formulation we show the validity of the convergence theorems for subtracted momentum space integrals, and we give the integral formulae necessary for one-loop calculations. (orig.).

  11. Optimisation of efficiency of axial fans

    NARCIS (Netherlands)

    Kruyt, Nicolaas P.; Pennings, P.C.; Faasen, R.

    2014-01-01

    A three-stage research project has been executed to develop ducted axial-fans with increased efficiency. In the first stage a design method has been developed in which various conflicting design criteria can be incorporated. Based on this design method, an optimised design has been determined

  12. Aryabha~ and Axial Rotation of Earth

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 11; Issue 4. Aryabhata and Axial Rotation of Earth - Naksatra Dina (the Sidereal Day). Amartya Kumar Dutta. General Article Volume 11 Issue 4 April 2006 pp 56-74. Fulltext. Click here to view fulltext PDF. Permanent link:

  13. Axial Hall effect and universality of holographic Weyl semi-metals

    Energy Technology Data Exchange (ETDEWEB)

    Copetti, Christian; Fernández-Pendás, Jorge; Landsteiner, Karl [Instituto de Física Teórica UAM/CSIC,c/ Nicolás Cabrera 13-15, Cantoblanco, 28049 Madrid (Spain)

    2017-02-28

    The holographic Weyl semimetal is a model of a strongly coupled topological semi-metal. A topological quantum phase transition separates a topological phase with non-vanishing anomalous Hall conductivity from a trivial state. We investigate how this phase transition depends on the parameters of the scalar potential (mass and quartic self coupling) finding that the quantum phase transition persists for a large region in parameter space. We then compute the axial Hall conductivity. The algebraic structure of the axial anomaly predicts it to be 1/3 of the electric Hall conductivity. We find that this holds once a non-trivial renormalization effect on the external axial gauge fields is taken into account. Finally we show that the phase transition also occurs in a top-down model based on a consistent truncation of type IIB supergravity.

  14. Linear optical response of carbon nanotubes under axial magnetic field

    Science.gov (United States)

    Moradian, Rostam; Chegel, Raad; Behzad, Somayeh

    2010-04-01

    We considered single walled carbon naotubes (SWCNTs) as real three dimensional (3D) systems in a cylindrical coordinate. The optical matrix elements and linear susceptibility, χ(ω), in the tight binding approximation in terms of one-dimensional wave vector, kz and subband index, l are calculated. In an external axial magnetic field optical frequency dependence of linear susceptibility are investigated. We found that axial magnetic field has two effects on the imaginary part of the linear susceptibility spectrum, in agreement with experimental results. The first effect is broadening and the second, splitting. Also we found that for all metallic zigzag and armchair SWCNTs, the axial magnetic field leads to the creation of a peak with energy less than 1.5 eV, contrary to what is observed in the absence of a magnetic field.

  15. Axially symmetrical stresses measurement in the cylindrical tube using DIC with hole-drilling

    Science.gov (United States)

    Ma, Yinji; Yao, Xuefeng; Zhang, Danwen

    2015-03-01

    In this paper, a new method combining the digital image correlation (DIC) with the hole-drilling technology to characterize the axially symmetrical stresses of the cylindrical tube is developed. First, the theoretical expressions of the axially symmetrical stresses in the cylindrical tube are derived based on the displacement or strain fields before and after hole-drilling. Second, the release of the axially symmetrical stresses for the cylindrical tube caused by hole-drilling is simulated by the finite element method (FEM), which indicates that the axially symmetrical stresses of the cylindrical tube calculated by the cylindrical solution is more accuracy than that for traditionally planar solution. Finally, both the speckle image information and the displacement field of the cylindrical tube before and after hole-drilling are extracted by combining the DIC with the hole-drilling technology, then the axially symmetrical loading induced stresses of the cylindrical tube are obtained, which agree well with the results from the strain gauge method.

  16. Axially alignable nuclear fuel pellets

    International Nuclear Information System (INIS)

    Johansson, E.B.; Klahn, D.H.; Marlowe, M.O.

    1978-01-01

    An axially alignable nuclear fuel pellet of the type stacked in end-to-end relationship within a tubular cladding is described. Fuel cladding failures can occur at pellet interface locations due to mechanical interaction between misaligned fuel pellets and the cladding. Mechanical interaction between the cladding and the fuel pellets loads the cladding and causes increased cladding stresses. Nuclear fuel pellets are provided with an end structure that increases plastic deformation of the pellets at the interface between pellets so that lower alignment forces are required to straighten axially misaligned pellets. Plastic deformation of the pellet ends results in less interactions beween the cladding and the fuel pellets and significantly lowers cladding stresses. The geometry of pellets constructed according to the invention also reduces alignment forces required to straighten fuel pellets that are tilted within the cladding. Plastic deformation of the pellets at the pellet interfaces is increased by providing pellets with at least one end face having a centrally-disposed raised area of convex shape so that the mean temperature and shear stress of the contact area is higher than that of prior art pellets

  17. Exact axially symmetric galactic dynamos

    Science.gov (United States)

    Henriksen, R. N.; Woodfinden, A.; Irwin, J. A.

    2018-05-01

    We give a selection of exact dynamos in axial symmetry on a galactic scale. These include some steady examples, at least one of which is wholly analytic in terms of simple functions and has been discussed elsewhere. Most solutions are found in terms of special functions, such as associated Lagrange or hypergeometric functions. They may be considered exact in the sense that they are known to any desired accuracy in principle. The new aspect developed here is to present scale-invariant solutions with zero resistivity that are self-similar in time. The time dependence is either a power law or an exponential factor, but since the geometry of the solution is self-similar in time we do not need to fix a time to study it. Several examples are discussed. Our results demonstrate (without the need to invoke any other mechanisms) X-shaped magnetic fields and (axially symmetric) magnetic spiral arms (both of which are well observed and documented) and predict reversing rotation measures in galaxy haloes (now observed in the CHANG-ES sample) as well as the fact that planar magnetic spirals are lifted into the galactic halo.

  18. Resolution of extra-axial collections after decompressive craniectomy for ischemic stroke.

    Science.gov (United States)

    Ropper, Alexander E; Nalbach, Stephen V; Lin, Ning; Dunn, Ian F; Gormley, William B

    2012-02-01

    Extra-axial fluid collections are known consequences of decompressive hemicraniectomy. Studies have examined these collections and their management. We retrospectively reviewed 12 consecutive patients who underwent decompressive hemicraniectomy for the treatment of malignant cerebral edema after infarction and evaluated the evolution, resolution and treatment of post-operative extra-axial fluid collections. All patients underwent standard-sized frontotemporoparietal hemicraniectomy with duraplasty as treatment for medically intractable malignant cerebral edema at an average of 3 days after the stroke (median 2 days). Their 30-day mortality was 25%. Three patients developed some extra-axial fluid collections after craniectomy: two patients developed the collections early in their post-operative course, 3 days and 5 days after the craniectomy. Both experienced spontaneous resolution of the collections without corrective cranioplasty or shunt placement at 34 days and 58 days after surgery. The third patient developed a collection 55 days after the operation related to a subgaleal bacterial infection. In the final analysis, 18% of patients developed extra-axial collections and all resolved spontaneously. The incidence of extra-axial collections after decompressive hemicraniectomy following ischemic stroke was lower in our retrospective series than has been reported by others. The collections resolved spontaneously, suggesting that early anticipatory, corrective treatment with cerebrospinal fluid diversion or cranioplasty may not be warranted. Copyright © 2011 Elsevier Ltd. All rights reserved.

  19. Axial oblique MR imaging of the intrinsic ligaments of the wrist: initial experience

    International Nuclear Information System (INIS)

    Robinson, G.; Chung, T.; Finlay, K.; Friedman, L.

    2006-01-01

    To evaluate two separate MR sequences acquired in the axial oblique plane, parallel to the long axis of the scapholunate (SL) and lunotriquetral (LT) ligaments, to determine whether the addition of these sequences to the standard MR wrist examination improves visualization of the intrinsic ligaments, and the evaluation of their integrity. To our knowledge, this plane has not been described in the literature previously. In total we evaluated 26 patients with chronic wrist pain or instability, referred for MR imaging following assessment by an orthopedic surgeon or physiatrist. All patients underwent initial conventional tri-compartment wrist arthrography, which served as the reference standard. This was immediately followed by MR arthrography, in the standard coronal and true axial planes, as well as in the axial oblique plane. The SL and LT ligaments were initially assessed for the presence or absence of tear, using the standard coronal and true axial sequences, and subsequently re-evaluated with the addition of the axial oblique planes. A total of ten intrinsic ligament tears were identified with conventional arthrography: six SL and four LT tears. Five of the six SL tears were identified on the standard sequences. All six were diagnosed with the addition of the oblique sequences. There were three false-positive SL tears identified using standard MR imaging, and two false-positives with the addition of the oblique sequences. No LT tear was identified on standard sequences, whereas all four were confidently seen with the addition of oblique images. No false-positives of the LT ligament were recorded with either standard or axial oblique sequences. The study suggests that the addition of axial oblique MR sequences helps identify tears to the intrinsic ligaments of the wrist, particularly the LT ligament. In addition, the axial oblique images assist in localization of the tear. (orig.)

  20. Automatic measurement of axial length of human eye using three-dimensional magnetic resonance imaging

    International Nuclear Information System (INIS)

    Watanabe, Masaki; Kiryu, Tohru

    2011-01-01

    The measurement of axial length and the evaluation of three dimensional (3D) form of an eye are essential to evaluate the mechanism of myopia progression. We propose a method of automatic measurement of axial length including adjustment of the pulse sequence of short-term scan which could suppress influence of eyeblink, using a magnetic resonance imaging (MRI) which acquires 3D images noninvasively. Acquiring T 2 -weighted images with 3.0 tesla MRI device and eight-channel phased-array head coil, we extracted left and right eye ball images, and then reconstructed 3D volume. The surface coordinates were calculated from 3D volume, fitting the ellipsoid model coordinates with the surface coordinates, and measured the axial length automatically. Measuring twenty one subjects, we compared the automatically measured values of axial length with the manually measured ones, then confirmed significant elongation in the axial length of myopia compared with that of emmetropia. Furthermore, there were no significant differences (P<0.05) between the means of automatic measurements and the manual ones. Accordingly, the automatic measurement process of axial length could be a tool for the elucidation of the mechanism of myopia progression, which would be suitable for evaluating the axial length easily and noninvasively. (author)

  1. Numerical investigation of the performances of axial separation helical baffle heat exchangers

    International Nuclear Information System (INIS)

    Tang, Hongling; Chen, Yaping; Wu, Jiafeng; Yang, Shifan

    2016-01-01

    Highlights: • Seriation incline angles of axial separation reduce helical baffle manufacture cost. • Adjacent helical baffles are separated by sleeve tubes to form a greater pitch helix. • Flow and thermal performances of normal and axial separation schemes were simulated. • Deviation of h.t.c. or pressure drop of 21(15)° and 21° schemes is −1.21% or 4.96%. • Seriation step of baffle incline angles can be extended to 8° by axial separation. - Abstract: Axial separation is a novel baffle connection configuration of circumferential overlap helical baffle heat exchangers which makes baffle incline angle seriation possible. The adjacent baffle plates are separated by sleeve tubes to form a greater pitched helix for enhancing heat transfer under required pressure drop with the least number of molds for reducing baffle manufacture cost. Numerical simulations of flow and heat transfer performances were conducted and the calculation results were verified by the experimental ones. Performance investigation was conducted on eight normal trisection helical baffle schemes with baffle incline angles from 15° to 23° and five axial separation schemes of equivalent 17–22° angles using 15° baffles. In the calculation scope the average deviations of heat transfer coefficients and pressure drops of the normal helical schemes are respectively about −1.97% and −8.11% per 1° deviation of incline angle. The axial separation schemes using 15° baffles with equivalent 21° and 22° incline angles have deviation values of heat transfer coefficient 1.21% and 1.33% lower and pressure drop 4.96% and 5.55% higher respectively than those of the normal 21° and 22° incline angle schemes. By adopting axial separation approach the seriation step of baffle incline angles can be extended to 8°.

  2. Electron–Cyclotron Laser Using Free-Electron Two-Quantum Stark Radiation in a Strong Uniform Axial Magnetic Field and an Alternating Axial Electric Field in a Voltage-Supplied Pill-Box Cavity

    International Nuclear Information System (INIS)

    Kim, S. H.

    2016-01-01

    We consider the radiation from the beam electrons traveling in a strong uniform axial magnetic field and an axial alternating electric field of wavelength λ_w generated by a voltage-supplied pill-box cavity. The beam electrons emit genuine laser radiation that propagates only in the axial direction through free-electron two-quantum Stark radiation. We find that laser radiation takes place only at the expense of the axial kinetic energy when λ_w ≪ c/(ω_c/γ), where ω_c/γ is the relativistic electron–cyclotron frequency. We formulate the laser power based on quantum-wiggler electrodynamics, and envision a laser of length 10 m with estimated power 0.1 GW/(kA) in the 10"−"4 cm wavelength range. (paper)

  3. Prevalence of soft tissue calcifications in cone beam computed tomography images of the mandible = Prevalência de calcificações em tecido mole na região mandibular avaliadas por dois sistemas de tomografia computadorizada por feixe cônico

    OpenAIRE

    Nunes, Leiliane Ferreira da Silva

    2011-01-01

    Objetivo: Determinar a prevalência de calcificações em tecido mole na região mandibular por meio de análise de imagens axiais provenientes de dois sistemas de tomografia computadorizada por feixe cônico (TCFC), NewTom 3G® e Classic i-Cat® Método: Foram avaliadas 246 imagens da região mandibular. Destas, 163 foram adquiridas no aparelho NewTom 3G® e 83 no aparelho Classic i-Cat®. A análise estatística foi baseada no teste exato de Fisher e no teste Qui-quadrado para comparação das proporçõe...

  4. Multi-axial mechanical stimulation of tissue engineered cartilage: Review

    Directory of Open Access Journals (Sweden)

    S D Waldman

    2007-04-01

    Full Text Available The development of tissue engineered cartilage is a promising new approach for the repair of damaged or diseased tissue. Since it has proven difficult to generate cartilaginous tissue with properties similar to that of native articular cartilage, several studies have used mechanical stimuli as a means to improve the quantity and quality of the developed tissue. In this study, we have investigated the effect of multi-axial loading applied during in vitro tissue formation to better reflect the physiological forces that chondrocytes are subjected to in vivo. Dynamic combined compression-shear stimulation (5% compression and 5% shear strain amplitudes increased both collagen and proteoglycan synthesis (76 ± 8% and 73 ± 5%, respectively over the static (unstimulated controls. When this multi-axial loading condition was applied to the chondrocyte cultures over a four week period, there were significant improvements in both extracellular matrix (ECM accumulation and the mechanical properties of the in vitro-formed tissue (3-fold increase in compressive modulus and 1.75-fold increase in shear modulus. Stimulated tissues were also significantly thinner than the static controls (19% reduction suggesting that there was a degree of ECM consolidation as a result of long-term multi-axial loading. This study demonstrated that stimulation by multi-axial forces can improve the quality of the in vitro-formed tissue, but additional studies are required to further optimize the conditions to favour improved biochemical and mechanical properties of the developed tissue.

  5. Investigation of multipactor breakdown in communication satellite microwave co-axial systems

    Science.gov (United States)

    Nagesh, S. K.; Revannasiddiah, D.; Shastry, S. V. K.

    2005-01-01

    Multipactor breakdown or multipactor discharge is a form of high frequency discharge that may occur in microwave components operating at very low pressures. Some RF components of multi-channel communication satellites have co-axial geometry and handle high RF power under near-vacuum conditions. The breakdown occurs due to secondary electron resonance, wherein electrons move back and forth in synchronism with the RF voltage across the gap between the inner and outer conductors of the co-axial structure. If the yield of secondary electrons from the walls of the co-axial structure is greater than unity, then the electron density increases with time and eventually leads to the breakdown. In this paper, the current due to the oscillating electrons in the co-axial geometry has been treated as a radially oriented Hertzian dipole. The electric field, due to this dipole, at any point in the coaxial structure, may then be determined by employing the dyadic Green's function technique. This field has been compared with the field that would exist in the absence of multipactor.

  6. The Co-axial Flow of Injectable Solid Hydrogels with Encapsulated Cells

    Science.gov (United States)

    Stewart, Brandon; Pochan, Darrin; Sathaye, Sameer

    2013-03-01

    Hydrogels are quickly becoming an important biomaterial that can be used for the safe, localized injection of cancer drugs, the injection of stem cells into areas of interest or other biological applications. Our peptides can be self-assembled in a syringe where they form a gel, sheared by injection and, once in the body, immediately reform a localized pocket of stiff gel. My project has been designed around looking at the possibility of having a co-axial strand, in which one gel can surround another. This co-axial flow can be used to change the physical properties of our gel during injection, such as stiffening our gel using hyaluronic acid or encapsulating cells in the gel and surrounding the gel with growth medium or other biological factors. Rheology on hyaluron stiffened gels and cells encapsulated in gels was performed for comparison to the results from co-axial flow. Confocal microscopy was used to examine the coaxial gels after flow and to determine how the co-axial nature of the gels is affected by the concentration of peptide.

  7. Study on Predicting Axial Load Capacity of CFST Columns

    Science.gov (United States)

    Ravi Kumar, H.; Muthu, K. U.; Kumar, N. S.

    2017-11-01

    This work presents an analytical study and experimental study on the behaviour and ultimate load carrying capacity of axially compressed self-compacting concrete-filled steel tubular columns. Results of tests conducted by various researchers on 213 samples concrete-filled steel tubular columns are reported and present authors experimental data are reported. Two theoretical equations were derived for the prediction of the ultimate axial load strength of concrete-filled steel tubular columns. The results from prediction were compared with the experimental data. Validation to the experimental results was made.

  8. Second harmonic generation of off axial vortex beam in the case of walk-off effect

    Science.gov (United States)

    Chen, Shunyi; Ding, Panfeng; Pu, Jixiong

    2016-07-01

    Process of off axial vortex beam propagating in negative uniaxial crystal is investigated in this work. Firstly, we get the formulae of the normalized electric field and calculate the location of vortices for second harmonic beam in two type of phase matching. Then, numerical analysis verifies that the intensity distribution and location of vortices of the first order original vortex beam depend on the walk-off angle and off axial magnitude. It is shown that, in type I phase matching, the distribution of vortices is symmetrical about the horizontal axis, the separation distance increases as the off axial magnitude increases or the off axial magnitude deceases. However, in type II phase matching, the vortices are symmetrical along with some vertical axis, and increase of the walk-off angle or off axial magnitude leads to larger separation distance. Finally, the case of high order original off axial vortex beam is also investigated.

  9. Launch Lock Assemblies Including Axial Gap Amplification Devices and Spacecraft Isolation Systems Including the Same

    Science.gov (United States)

    Barber, Tim Daniel (Inventor); Hindle, Timothy (Inventor); Young, Ken (Inventor); Davis, Torey (Inventor)

    2014-01-01

    Embodiments of a launch lock assembly are provided, as are embodiments of a spacecraft isolation system including one or more launch lock assemblies. In one embodiment, the launch lock assembly includes first and second mount pieces, a releasable clamp device, and an axial gap amplification device. The releasable clamp device normally maintains the first and second mount pieces in clamped engagement; and, when actuated, releases the first and second mount pieces from clamped engagement to allow relative axial motion there between. The axial gap amplification device normally residing in a blocking position wherein the gap amplification device obstructs relative axial motion between the first and second mount pieces. The axial gap amplification device moves into a non-blocking position when the first and second mount pieces are released from clamped engagement to increase the range of axial motion between the first and second mount pieces.

  10. A tubular hybrid Halbach/axially-magnetized permanent-magnet linear machine

    Directory of Open Access Journals (Sweden)

    Yi Sui

    2017-05-01

    Full Text Available A single-phase tubular permanent-magnet linear machine (PMLM with hybrid Halbach/axially-magnetized PM arrays is proposed for free-piston Stirling power generation system. Machine topology and operating principle are elaborately illustrated. With the sinusoidal speed characteristic of the free-piston Stirling engine considered, the proposed machine is designed and calculated by finite-element analysis (FEA. The main structural parameters, such as outer radius of the mover, radial length of both the axially-magnetized PMs and ferromagnetic poles, axial length of both the middle and end radially-magnetized PMs, etc., are optimized to improve both the force capability and power density. Compared with the conventional PMLMs, the proposed machine features high mass and volume power density, and has the advantages of simple control and low converter cost. The proposed machine topology is applicable to tubular PMLMs with any phases.

  11. A tubular hybrid Halbach/axially-magnetized permanent-magnet linear machine

    Science.gov (United States)

    Sui, Yi; Liu, Yong; Cheng, Luming; Liu, Jiaqi; Zheng, Ping

    2017-05-01

    A single-phase tubular permanent-magnet linear machine (PMLM) with hybrid Halbach/axially-magnetized PM arrays is proposed for free-piston Stirling power generation system. Machine topology and operating principle are elaborately illustrated. With the sinusoidal speed characteristic of the free-piston Stirling engine considered, the proposed machine is designed and calculated by finite-element analysis (FEA). The main structural parameters, such as outer radius of the mover, radial length of both the axially-magnetized PMs and ferromagnetic poles, axial length of both the middle and end radially-magnetized PMs, etc., are optimized to improve both the force capability and power density. Compared with the conventional PMLMs, the proposed machine features high mass and volume power density, and has the advantages of simple control and low converter cost. The proposed machine topology is applicable to tubular PMLMs with any phases.

  12. Cdx and Hox genes differentially regulate posterior axial growth in mammalian embryos

    NARCIS (Netherlands)

    Young, Teddy; Rowland, Jennifer Elizabeth; van de Ven, Cesca; Bialecka, Monika; Novoa, Ana; Carapuco, Marta; van Nes, Johan; de Graaff, Wim; Duluc, Isabelle; Freund, Jean-Noël; Beck, Felix; Mallo, Moises; Deschamps, Jacqueline

    2009-01-01

    Hox and Cdx transcription factors regulate embryonic positional identities. Cdx mutant mice display posterior body truncations of the axial skeleton, neuraxis, and caudal urorectal structures. We show that trunk Hox genes stimulate axial extension, as they can largely rescue these Cdx mutant

  13. The Nucleon Axial Form Factor and Staggered Lattice QCD

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Aaron Scott [Chicago U.

    2017-01-01

    The study of neutrino oscillation physics is a major research goal of the worldwide particle physics program over the upcoming decade. Many new experiments are being built to study the properties of neutrinos and to answer questions about the phenomenon of neutrino oscillation. These experiments need precise theoretical cross sections in order to access fundamental neutrino properties. Neutrino oscillation experiments often use large atomic nuclei as scattering targets, which are challenging for theorists to model. Nuclear models rely on free-nucleon amplitudes as inputs. These amplitudes are constrained by scattering experiments with large nuclear targets that rely on the very same nuclear models. The work in this dissertation is the rst step of a new initiative to isolate and compute elementary amplitudes with theoretical calculations to support the neutrino oscillation experimental program. Here, the eort focuses on computing the axial form factor, which is the largest contributor of systematic error in the primary signal measurement process for neutrino oscillation studies, quasielastic scattering. Two approaches are taken. First, neutrino scattering data on a deuterium target are reanalyzed with a model-independent parametrization of the axial form factor to quantify the present uncertainty in the free-nucleon amplitudes. The uncertainties on the free-nucleon cross section are found to be underestimated by about an order of magnitude compared to the ubiquitous dipole model parametrization. The second approach uses lattice QCD to perform a rst-principles computation of the nucleon axial form factor. The Highly Improved Staggered Quark (HISQ) action is employed for both valence and sea quarks. The results presented in this dissertation are computed at physical pion mass for one lattice spacing. This work presents a computation of the axial form factor at zero momentum transfer, and forms the basis for a computation of the axial form factor momentum dependence

  14. Numerical investigations on axial and radial blade rubs in turbo-machinery

    Science.gov (United States)

    Abdelrhman, Ahmed M.; Tang, Eric Sang Sung; Salman Leong, M.; Al-Qrimli, Haidar F.; Rajamohan, G.

    2017-07-01

    In the recent years, the clearance between the rotor blades and stator/casing had been getting smaller and smaller prior improving the aerodynamic efficiency of the turbomachines as demand in the engineering field. Due to the clearance reduction between the blade tip and the rotor casing and between rotor blades and stator blades, axial and radial blade rubbing could be occurred, especially at high speed resulting into complex nonlinear vibrations. The primary aim of this study is to address the blade axial rubbing phenomenon using numerical analysis of rotor system. A comparison between rubbing caused impacts of axial and radial blade rubbing and rubbing forces are also aims of this study. Tow rotor models (rotor-stator and rotor casing models) has been designed and sketched using SOILDSWORKS software. ANSYS software has been used for the simulation and the numerical analysis. The rubbing conditions were simulated at speed range of 1000rpm, 1500rpm and 2000rpm. Analysis results for axial blade rubbing showed the appearance of blade passing frequency and its multiple frequencies (lx, 2x 3x etc.) and these frequencies will more excited with increasing the rotational speed. Also, it has been observed that when the rotating speed increased, the rubbing force and the harmonics frequencies in x, y and z-direction become higher and severe. The comparison study showed that axial blade rub is more dangerous and would generate a higher vibration impacts and higher blade rubbing force than radial blade rub.

  15. Studies of axial-leakage simulations for homogeneous and heterogeneous EBR-II core configurations

    International Nuclear Information System (INIS)

    Grimm, K.N.; Meneghetti, D.

    1985-08-01

    When calculations of flux are done in less than three dimensions, leakage-absorption cross sections are normally used to model leakages (flows) in the dimensions for which the flux is not calculated. Since the neutron flux is axially dependent, the leakages, and hence the leakage-absorption cross sections, are also axially dependent. Therefore, to obtain axial flux profiles (or reaction rates) for individual subassemblies, an XY-geometry calculation delineating each subassembly has to be done at several axial heights with space- and energy-dependent leakage-absorption cross sections that are appropriate for each height. This report discusses homogeneous and heterogeneous XY-geometry calculations at various axial locations and using several differing assumptions for the calculation of the leakage-absorption cross section. The positive (outward) leakage-absorption cross sections are modeled as actual leakage absorptions, but the negative (inward) leakage-absorption cross sections are modeled as either negative leakage absorptions (+-B 2 method) or positive downscatter cross sections [the Σ/sub s/(1 → g) method]. 3 refs., 52 figs., 10 tabs

  16. Fibrose maciça progressiva em trabalhadores expostos à sílica: achados na tomografia computadorizada de alta resolução Progressive massive fibrosis in silica-exposed workers: high-resolution computed tomography findings

    Directory of Open Access Journals (Sweden)

    Ângela Santos Ferreira

    2006-12-01

    Full Text Available OBJETIVO: Avaliar as características radiológicas das massas conglomeradas pela tomografia computadorizada de alta resolução de tórax. MÉTODOS: Foram selecionados 75 pacientes silicóticos, a maioria jateadores de areia, portadores de fibrose maciça progressiva, atendidos no Hospital Universitário Antônio Pedro entre 1986 e 2004. Os pacientes foram submetidos a avaliação clínica, radiografia simples de tórax e tomografia computadorizada de alta resolução. RESULTADOS: Mais da metade dos pacientes com silicose complicada mostrou na radiografia de tórax grandes opacidades dos tipos B e C, denotando a gravidade da doença nesses pacientes. Dos 75 casos, apenas um apresentou massa unilateral simulando câncer de pulmão. Quarenta e quatro pacientes realizaram tomografia computadorizada de alta resolução do tórax. As massas predominaram nos terços superiores e posteriores (88,6%. Broncograma aéreo e calcificações no interior das massas foram observados em 70,4% e 63,8% dos casos, respectivamente. História de tuberculose foi relatada em 52% dos pacientes estudados. CONCLUSÃO: Na grande maioria dos casos as massas eram bilaterais, predominando nas regiões póstero-superiores dos pulmões, com broncogramas aéreos e calcificações de permeio. Associação com calcificações linfonodais foi um achado freqüente. A exposição a elevadas concentrações de poeira e a tuberculose foram consideradas fatores de risco para o desenvolvimento da fibrose maciça progressiva.OBJECTIVE: To evaluate the radiological characteristics of conglomerate masses using high-resolution computed tomography of the chest. METHODS: From among the patients treated between 1986 and 2004 at the Antonio Pedro University Hospital, 75 patients with silicosis and massive fibrosis, most working in the field of sandblasting, were selected for study. These patients were submitted to a clinical evaluation, chest X-ray and high-resolution computed tomography of

  17. Particle flow of ceramic breeder pebble beds in bi-axial compression experiments

    International Nuclear Information System (INIS)

    Hermsmeyer, S.; Reimann, J.

    2002-01-01

    Pebble beds of ceramic material are investigated within the framework of developing solid breeder blankets for future fusion power plants. A thermo-mechanical characterisation of such pebble beds is mandatory for understanding the behaviour of pebble beds, and thus the overall blanket, under fusion environment conditions. The mechanical behaviour of pebble beds is typically explored with uni-axial, bi-axial and tri-axial compression experiments. The latter two types of experiment are particularly revealing since they contain explicitly, beyond a compression behaviour of the bed, information on the conditions for pebble flow, i.e. macroscopic relocation, in the pebble bed. (orig.)

  18. VERY SLOW SPEED AXIAL MOTION RELUCTANCE MOTOR

    African Journals Online (AJOL)

    Dr Obe

    1984-09-01

    Sep 1, 1984 ... VERY SLOW SPEED AXIAL MOTION RELUCTANCE MOTOR by. L. A. Agu ... order as that of the screw-thread motor can be obtained. LIST OF .... The n stator have equal non- magnetic spacers .... induction motor. An.

  19. A double-superconducting axial bearing system for an energy storage flywheel model

    Science.gov (United States)

    Deng, Z.; Lin, Q.; Ma, G.; Zheng, J.; Zhang, Y.; Wang, S.; Wang, J.

    2008-02-01

    The bulk high temperature superconductors (HTSCs) with unique flux-pinning property have been applied to fabricate two superconducting axial bearings for an energy storage flywheel model. The two superconducting axial bearings are respectively fixed at two ends of the vertical rotational shaft, whose stator is composed of seven melt-textured YBa2Cu3O7-x (YBCO) bulks with diameter of 30 mm, height of 18 mm and rotor is made of three cylindrical axial-magnetized NdFeB permanent magnets (PM) by superposition with diameter of 63 mm, height of 27 mm. The experimental results show the total levitation and lateral force produced by the two superconducting bearings are enough to levitate and stabilize the 2.4 kg rotational shaft. When the two YBCO stators were both field cooled to the liquid nitrogen temperature at respective axial distances above or below the PM rotor, the shaft could be automatically levitated between the two stators without any contact. In the case of a driving motor, it can be stably rotated along the central axis besides the resonance frequency. This double-superconducting axial bearing system can be used to demonstrate the flux-pinning property of bulk HTSC for stable levitation and suspension and the principle of superconducting flywheel energy storage system to visitors.

  20. Axial force in a superconductor magnet journal bearing

    Science.gov (United States)

    Postrekhin, E.; Chong, Wang; Ki Bui, Ma; Chen, Quark; Chu, Wei-Kan

    Using superconductors and magnets, a journal bearing could be made from a permanent magnet cylinder in a superconductor ring. We have assembled a prototype superconductor magnet journal bearing of this configuration, and investigated the behavior of the axial force that it can provide. We have put together a numerical model of the interaction between the permanent magnet and the superconductor that is capable of describing these experimental results semi-quantitatively. Combining direct experimental measurements and using the numerical models proposed, we have achieved a qualitative understanding of the behavior of the axial force and its relationship of to the dimensions of the magnet and material quality such as the homogeneity of the superconductor that constitute the bearing.

  1. Imaging results and TOF studies with axial PET detectors

    Science.gov (United States)

    Joram, Christian

    2013-12-01

    We have developed a fully operational PET demonstrator setup which allows true 3D reconstruction of the 511 keV photons and therefore leads to practically parallax free images. The AX-PET concept is based on thin 100 mm long scintillation crystals (LYSO), axially oriented and arranged in layers around the field of view. Layers of wavelength shifting plastic strips mounted in between the crystal layers give the axial coordinate. Both crystals and WLS strips are individually read out by G-APD (SiPM) photodetectors. The fully scalable concept overcomes the dilemma of sensitivity versus spatial resolution which is inherent to classical PET designs. A demonstrator set-up based on two axial modules was exhaustively characterized using point-like sources, phantoms filled with radiotracer and finally rats and a mouse. The results entirely meet the performance expectations (PET concept making use of the novel digital SiPM detectors by Philips. After reproducing comparable energy and spatial resolution on a small digital AX-PET set-up with 100 mm long crystals, we demonstrated a coincidence resolving time of about 210 ps FWHM.

  2. Bifurcation of cubic nonlinear parallel plate-type structure in axial flow

    International Nuclear Information System (INIS)

    Lu Li; Yang Yiren

    2005-01-01

    The Hopf bifurcation of plate-type beams with cubic nonlinear stiffness in axial flow was studied. By assuming that all the plates have the same deflections at any instant, the nonlinear model of plate-type beam in axial flow was established. The partial differential equation was turned into an ordinary differential equation by using Galerkin method. A new algebraic criterion of Hopf bifurcation was utilized to in our analysis. The results show that there's no Hopf bifurcation for simply supported plate-type beams while the cantilevered plate-type beams has. At last, the analytic expression of critical flow velocity of cantilevered plate-type beams in axial flow and the purely imaginary eigenvalues of the corresponding linear system were gotten. (authors)

  3. ABOUT MODELING COMPLEX ASSEMBLIES IN SOLIDWORKS – LARGE AXIAL BEARING

    Directory of Open Access Journals (Sweden)

    Cătălin IANCU

    2017-12-01

    Full Text Available In this paperwork is presented the modeling strategy used in SOLIDWORKS for modeling special items as large axial bearing and the steps to be taken in order to obtain a better design. In the paper are presented the features that are used for modeling parts, and then the steps that must be taken in order to obtain the 3D model of a large axial bearing used for bucket-wheel equipment for charcoal moving.

  4. The research on flow pulsation characteristics of axial piston pump

    Science.gov (United States)

    Wang, Bingchao; Wang, Yulin

    2017-01-01

    The flow pulsation is an important factor influencing the axial piston pump performance. In this paper we implement modeling and simulation of the axial piston pump with AMESim software to explore the flow pulsation characteristics under various factors . Theory analysis shows the loading pressure, angular speed, piston numbers and the accumulator impose evident influence on the flow pulsation characteristics. This simulation and analysis can be used for reducing the flow pulsation rate via properly setting the related factors.

  5. A review of creep analysis and design under multi-axial stress states

    International Nuclear Information System (INIS)

    Yao, H.-T.; Xuan Fuzhen; Wang Zhengdong; Tu Shantung

    2007-01-01

    The existence of multi-axial states of stress cannot be avoided in elevated temperature components. It is essential to understand the associated failure mechanisms and to predict the lifetime in practice. Although metal creep has been studied for about 100 years, many problems are still unsolved, in particular for those involving multi-axial stresses. In this work, a state-of-the-art review of creep analysis and engineering design is carried out, with particular emphasis on the effect of multi-axial stresses. The existing theories and creep design approaches are grouped into three categories, i.e., the classical plastic theory (CPT) based approach, the cavity growth mechanism (CGM) based approach and the continuum damage mechanics (CDM) based approach. Following above arrangements, the constitutive equations and design criteria are addressed. In the end, challenges on the precise description of the multi-axial creep behavior and then improving the strength criteria in engineering design are presented

  6. Axial Force Analysis and Roll Contour Configuration of Four-High CVC Mill

    Directory of Open Access Journals (Sweden)

    Guang-ming Liu

    2018-01-01

    Full Text Available In order to analyze the influence of technical parameters on work roll axial force of four-high continuous variable crown (CVC mill, the deformation analyzing model with top roll system and strip was established based on influence function method. Then a CVC work roll curve designing scheme was proposed and it was carried out on some cold rolling mill considering the requirement of comprehensive work roll axial force minimization. The status of comprehensive work roll axial force is improved considering the rolling schedule that is beneficial to the roller bearing. Corresponding to the newly designed work roll contour, the backup roll end chamfer was designed considering comprehensive performance of interroll stress concentration, comprehensive work roll axial force, and strip shape control ability. The distribution of roll wear with newly designed backup roll contour is more even according to the field application data. The newly established roll configuration scheme is beneficial to four-high CVC mill.

  7. Colonic surveillance by CT colonography using axial images only

    International Nuclear Information System (INIS)

    Bruzzi, John F.; Brennan, Darren D.; Fenlon, Helen M.; Moss, Alan C.; MacMathuna, Padraic

    2004-01-01

    Patients at increased risk of colon cancer require strict colon surveillance. Our objective was to establish the efficacy of 2D axial CT colonography as a surveillance test when performed in routine clinical practice. Eighty-two patients at increased risk of colon cancer underwent CT colonography followed by conventional colonoscopy on the same morning. CT colonography studies were performed on a four-ring multidetector CT scanner (100 mAs, 120 kVp, 4 x 2.5 collimation) and were interpreted by two radiologists using 2D axial images only. Results were correlated with findings at colonoscopy. Note was made of subsequent histology reports from polypectomy specimens. A total of 52 polyps were detected at colonoscopy. Using 2D axial images alone, with no recourse to 2D multiplanar or 3D views, the sensitivity of CT colonography was 100, 33 and 19% for polyps larger than 9, 6-9 and smaller than 6 mm, respectively. Per-patient specificities were 98.8, 96 and 81.5%, respectively. Twenty-nine percent of polyps smaller than 1 cm were adenomatous and there were no histological features of severe dysplasia. CT colonography is a useful colon surveillance tool for patients at increased risk of colon cancer. It has a high specificity for identifying patients who should proceed to colonoscopy and polypectomy, while allowing further colon examination to be deferred in patients with normal studies. Using 2D axial images only, CT colonography can be performed as part of the daily CT workload, with a very low rate of referral for unnecessary colonoscopy. (orig.)

  8. The Influence of the Axial Magnetic Field Upon-the Coaxial Plasma Gun Parameters

    International Nuclear Information System (INIS)

    El-Aragi, G.M.; EL-Demrdash, A.

    2001-01-01

    This study concerns with the influence of an applied axial magnetic field upon the electrical parameters of a coaxial plasma gun device. The experimental results are investigated with 0.5 KJ plasma gun device operated with argon gas at a pressure of 3.5 Torr. An axial time independent magnetic field with intensity of 550 G is introduced along the plasma current sheath axial region, within the annular space between the two coaxial electrodes. From the measurements of the discharge current I(t) and the voltage V(t), the electrical discharge parameters of the plasma gun device and the plasma current sheath implosion velocity are estimated, in normal mode of plasma gun operation and in the mode of presence external axial magnetic field. A comparison between these two modes is studied

  9. Axial power difference control strategy and computer simulation for GNPS during stretch-out and power decrease

    International Nuclear Information System (INIS)

    Liao Yehong; Xiao Min; Li Xianfeng; Zhu Minhong

    2004-01-01

    Successful control of the axial power difference for PWR is crucial to nuclear safety. After analyzing various elements' effect on the axial power distribution, different axial power deviation control strategies have been proposed to comply with different power decrease scenarios. Application of the strategy to computer simulation shows that our prediction of axial power deviation evolution is comparable to the measurement value, and that our control strategy is effective

  10. THE EFFECT OF VARIATION CONCRETE CUBE OF AXIAL LOAD ON ULTRASONIC PULSE VELOCITY TRANSMITTER

    Directory of Open Access Journals (Sweden)

    Faqih Ma’arif

    2015-05-01

    The test result showed that the increase of ultrasonic pulse velocity effect on cube II due to axial load variation was optimum at 0,35P0 and was minimum at 0,7P0, if compared to the one without axial load, the results were 4,17% and 11,60 respectively. The decrease of pulse velocity on cube III due to axial load variation was at 0,25P0 and 0,7P0; if compared to the one without axial load the result were 0,47% and 20,87% respectively. And the increase of ultrasonic pulse velocity effect on cube IV due to axial load variation was optimum at 0,35P0 and was minimum at 0,7P0; if compared to the one without axial load the result were 0,52% and 21,63% respectively. The maximum limit of effective load step at structure experiencing compressive load ranged from 0,35P0 up to 0,4P0. At high stress level, the crack that occurred was spread evenly to the concrete cubic components and was giving an exponential equation y = y= 5,11e0,0467x. The result of analysis of cubes II, III and IV showed that on paired sample t-test 0,00<0,025, the significant value (2-tailed (0,00<(0,025; meaning there was a difference of pulse velocity due to axial load variation on concrete cube.

  11. Dispersive approach to the axial anomaly and nonrenormalization theorem

    International Nuclear Information System (INIS)

    Pasechnik, R.S.; Teryaev, O.V.

    2006-01-01

    Anomalous triangle graphs for the divergence of the axial-vector current are studied using the dispersive approach generalized for the case of higher orders of perturbation theory. The validity of this procedure is proved up to the two-loop level. By direct calculation in the framework of dispersive approach we have obtained that the two-loop axial-vector-vector (AVV) amplitude is equal to zero. According to the Vainshtein's theorem, the transversal part of the anomalous triangle is not renormalized in the chiral limit. We generalize this theorem for the case of finite fermion mass in the triangle loop

  12. Are Upper-Body Axial Symptoms a Feature of Early Parkinson’s Disease?

    Science.gov (United States)

    Moreau, Caroline; Baille, Guillaume; Delval, Arnaud; Tard, Céline; Perez, Thierry; Danel-Buhl, Nicolas; Seguy, David; Labreuche, Julien; Duhamel, Alain; Delliaux, Marie; Dujardin, Kathy; Defebvre, Luc

    2016-01-01

    Background Axial disorders are considered to appear late in the course of Parkinson’s disease (PD). The associated impact on quality of life (QoL) and survival and the lack of an effective treatment mean that understanding and treating axial disorders is a key challenge. However, upper-body axial disorders (namely dysarthria, swallowing and breathing disorders) have never been prospectively assessed in early-stage PD patients. Objectives To characterize upper-body axial symptoms and QoL in consecutive patients with early-stage PD. Methods We prospectively enrolled 66 consecutive patients with early-stage PD (less than 3 years of disease progression) and assessed dysarthria, dysphagia and respiratory function (relative to 36 controls) using both objective and patient-reported outcomes. Results The mean disease duration was 1.26 years and the mean UPDRS motor score was 19.4 out of 108. 74% of the patients presented slight dysarthria (primarily dysprosodia). Men appeared to be more severely affected (i.e. dysphonia). This dysfunction was strongly correlated with low swallowing speed (despite the absence of complaints about dysphagia), respiratory insufficiency and poor QoL. Videofluorography showed that oral-phase swallowing disorders affected 60% of the 31 tested patients and that pharyngeal-phase disorders affected 21%. 24% of the patients reported occasional dyspnea, which was correlated with anxiety in women but not in men. Marked diaphragmatic dysfunction was suspected in 42% of the patients (predominantly in men). Conclusion Upper body axial symptoms were frequent in men with early-stage PD, whereas women presented worst non-motor impairments. New assessment methods are required because currently available tools do not reliably detect these upper-body axial disorders. PMID:27654040

  13. Referral patterns, diagnosis, and disease management of patients with axial spondyloarthritis: results of an international survey.

    Science.gov (United States)

    van der Heijde, Désirée; Sieper, Joachim; Elewaut, Dirk; Deodhar, Atul; Pangan, Aileen L; Dorr, Alexander P

    2014-12-01

    Recognition, diagnosis, and management of axial spondyloarthritis (axial SpA) continue to advance. The objectives of this study were to compare referrals, diagnosis, and management of axial SpA in Western Europe (WE), North America (US and Canada), and the rest of world (RoW) in academic and community rheumatology practices and to identify areas for further education. Rheumatologists responded online to the MAXIMA (Management of Axial SpA International and Multicentric Approaches) survey. Questions pertained to referral, diagnosis, and management of axial SpA. Rheumatologists (N = 809) from 56 countries completed the survey about patients with chronic back pain (≥3 months) starting before age 45 years. Responses from academic and community practice rheumatologists were generally similar. Most referrals were from primary care providers. Symptom duration of 3 years or more at referral was reported more frequently by WE and RoW than US respondents. More WE and RoW than US rheumatologists referred to the Assessment of SpondyloArthritis International Society criteria for axial SpA in clinical practice. Rheumatologists reported prescribing disease-modifying antirheumatic drugs for the management of axial SpA. Sulfasalazine was frequently prescribed across regions; methotrexate was more commonly prescribed by US rheumatologists compared with other regions. Referral patterns, diagnosis, and disease management for axial SpA were similar among WE, North America, and RoW rheumatologists and in academic/community practices, although more WE and RoW rheumatologists referred to Assessment of SpondyloArthritis International Society criteria in clinical practice. Disease-modifying antirheumatic drugs were commonly prescribed for axial SpA patients, although it was unclear whether these were prescribed for axial or peripheral symptoms.

  14. Multiaxial ratcheting behavior of zirconium alloy tubes under combined cyclic axial load and internal pressure

    Energy Technology Data Exchange (ETDEWEB)

    Chen, G.; Zhang, X. [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Xu, D.K. [Environmental Corrosion Center, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Li, D.H. [Hunan Taohuajiang Nuclear Power Co., Ltd, Yiyang, 413000 (China); Chen, X. [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Zhang, Z., E-mail: zhe.zhang@tju.edu.cn [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China)

    2017-06-15

    In this study, a series of uniaxial and multiaxial ratcheting tests were conducted at room temperature on zirconium alloy tubes. The experimental results showed that for uniaxial symmetrical cyclic test, the axial ratcheting strain ɛ{sub x} did not accumulate obviously in initial stage, but gradually increased up to 1% with increasing stress amplitude σ{sub xa}. For multiaxial ratcheting tests, the zirconium alloy tube was highly sensitive to both the axial stress amplitude σ{sub xa} and the internal pressure p{sub i}. The hoop ratcheting strain ɛ{sub θ} increased continuously with the increase of axial stress amplitude, whereas the evolution of axial ratcheting strain ɛ{sub x} was related to the axial stress amplitude. The internal pressure restricted the ratcheting accumulation in the axial direction, but promoted the hoop ratcheting strain on the contrary. The prior loading history greatly restrained the ratcheting behavior of subsequent cycling with a small internal pressure. - Highlights: •Uniaxial and multiaxial ratcheting behavior of the zirconium alloy tubes are investigated at room temperature. •The ratcheting depends greatly on the stress amplitude or internal pressure. •The interaction between the axial and hoop ratcheting mechanisms is greatly dependent on the internal pressure level. •The ratcheting is influenced significantly by the loading history of internal pressure.

  15. Multiaxial ratcheting behavior of zirconium alloy tubes under combined cyclic axial load and internal pressure

    International Nuclear Information System (INIS)

    Chen, G.; Zhang, X.; Xu, D.K.; Li, D.H.; Chen, X.; Zhang, Z.

    2017-01-01

    In this study, a series of uniaxial and multiaxial ratcheting tests were conducted at room temperature on zirconium alloy tubes. The experimental results showed that for uniaxial symmetrical cyclic test, the axial ratcheting strain ɛ x did not accumulate obviously in initial stage, but gradually increased up to 1% with increasing stress amplitude σ xa . For multiaxial ratcheting tests, the zirconium alloy tube was highly sensitive to both the axial stress amplitude σ xa and the internal pressure p i . The hoop ratcheting strain ɛ θ increased continuously with the increase of axial stress amplitude, whereas the evolution of axial ratcheting strain ɛ x was related to the axial stress amplitude. The internal pressure restricted the ratcheting accumulation in the axial direction, but promoted the hoop ratcheting strain on the contrary. The prior loading history greatly restrained the ratcheting behavior of subsequent cycling with a small internal pressure. - Highlights: •Uniaxial and multiaxial ratcheting behavior of the zirconium alloy tubes are investigated at room temperature. •The ratcheting depends greatly on the stress amplitude or internal pressure. •The interaction between the axial and hoop ratcheting mechanisms is greatly dependent on the internal pressure level. •The ratcheting is influenced significantly by the loading history of internal pressure.

  16. Análise das variações morfológicas da ATM em pacientes com artrite reumatóide através de tomografia computadorizada = Analysis of the morphologyc variations in the TMJ the patients with rheumatoid arthritis through the computer tomography

    Directory of Open Access Journals (Sweden)

    Vasconcelos, Belmiro Cavalcanti do Egito

    2005-01-01

    Full Text Available Realizou-se um estudo qualitativo e quantitativo enfocando as alterações morfométricas da articulação temporomandibular (ATM, em pacientes com o diagnóstico de artrite reumatóide (AR por meio de tomografia computadorizada. Foram analisados 6 casos onde são descritas as alterações estruturais dos componentes ósseos de 12 ATMs. Os resultados indicaram que todas as ATMs apresentaram alterações, sendo as alterações mais freqüentes a esclerose óssea subcondral, seguida do aplainamento da eminência articular. Todos os pacientes apresentaram distúrbio de mobilidade

  17. Anisotropic Material Behavior of Uni-axially Compacted Graphite Matrix for HTGR Fuel Compact Fabrication

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Young-Woo; Yeo, Seunghwan; Yoon, Ji-Hae; Cho, Moon Sung [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    In developing the fuel compact fabrication technology, and fuel graphite material to meet the required material properties, it is essential to investigate the relationship among the process parameters of the matrix graphite powder preparation, the fabrication parameters of fuel element green compact and the heat treatments conditions and the material properties of fuel element. It was observed, during this development, that the pressing technique employed for the compaction fabrication prior to the two successive heat treatments (carbonization and final high temperature heat treatment) was of extreme importance in determining the material properties of the final compact product. In this work, the material behavior of the uni-axially pressed graphite matrix during the carbonization and final heat treatment are evaluated and summarized along the different directions, viz., perpendicular and parallel directions to pressing direction. In this work, the dimensional variations and variations in thermal expansion, thermal conductivity and Vickers hardness of the graphite matrix compact samples in the axial and radial directions prepared by uni-axial pressing are evaluated, and compared with those of samples prepared by cold isostatic pressing with the available data. From this work, the followings are observed. 1) Dimensional changes of matrix graphite green compacts during carbonization show that the difference in radial and axial variations shows a large anisotropic behavior in shrinkage. The radial variation is very small while the axial variation is large. During carbonization, the stresses caused by the force would be released in to the axial direction together with the phenolic resin vapor. 2) Dimensional variation of compact samples in perpendicular and parallel directions during carbonization shows a large difference in behavior when compact sample is prepared by uni-axial pressing. However, when compact sample is prepared by cold isostatic pressing, there is

  18. Anisotropic Material Behavior of Uni-axially Compacted Graphite Matrix for HTGR Fuel Compact Fabrication

    International Nuclear Information System (INIS)

    Lee, Young-Woo; Yeo, Seunghwan; Yoon, Ji-Hae; Cho, Moon Sung

    2016-01-01

    In developing the fuel compact fabrication technology, and fuel graphite material to meet the required material properties, it is essential to investigate the relationship among the process parameters of the matrix graphite powder preparation, the fabrication parameters of fuel element green compact and the heat treatments conditions and the material properties of fuel element. It was observed, during this development, that the pressing technique employed for the compaction fabrication prior to the two successive heat treatments (carbonization and final high temperature heat treatment) was of extreme importance in determining the material properties of the final compact product. In this work, the material behavior of the uni-axially pressed graphite matrix during the carbonization and final heat treatment are evaluated and summarized along the different directions, viz., perpendicular and parallel directions to pressing direction. In this work, the dimensional variations and variations in thermal expansion, thermal conductivity and Vickers hardness of the graphite matrix compact samples in the axial and radial directions prepared by uni-axial pressing are evaluated, and compared with those of samples prepared by cold isostatic pressing with the available data. From this work, the followings are observed. 1) Dimensional changes of matrix graphite green compacts during carbonization show that the difference in radial and axial variations shows a large anisotropic behavior in shrinkage. The radial variation is very small while the axial variation is large. During carbonization, the stresses caused by the force would be released in to the axial direction together with the phenolic resin vapor. 2) Dimensional variation of compact samples in perpendicular and parallel directions during carbonization shows a large difference in behavior when compact sample is prepared by uni-axial pressing. However, when compact sample is prepared by cold isostatic pressing, there is

  19. Axially substituted silicon (IV) tetrapyrazinoporphyrazines: Synthesis, characterization and investigation of photophysicochemical properties

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Chang Young; Park, Jong Min; Song, Cheol Jun; Jaung, Jae Yun, E-mail: jjy1004@hanyang.ac.kr

    2016-02-15

    A series of silicon tetrapyrazinoporphyrazine (SiPz) complexes, conjugated with various substituents at their axial positions, were synthesized into non-aggregated structures in organic solvents. The UV–vis spectra of the SiPz complexes maintained a strong and sharp Q-band, which is an archetypal characteristic of non-aggregated phthalocyanines (Pcs), in various organic solvents under high concentrations. In addition, the SiPz complexes with axial alkyl groups had high fluorescence quantum yields and singlet oxygen quantum yields. However, the SiPz complexes with axial aniline groups had very low fluorescence quantum yields and singlet oxygen quantum yields due to the quenching ability of the aniline group.

  20. Metodología para la manufactura de implantes craneales a partir de imágenes DICOM y tecnologías CAD/CAM/CNC Metodología para la manufactura de implantes craneales a partir de imágenes DICOM y tecnologías CAD/CAM/CNC

    Directory of Open Access Journals (Sweden)

    Iván López

    2005-12-01

    Full Text Available El presente artículo propone una metodología para el diseño y la fabricación de implantes craneales a partir de imágenes DICOM y tecnologías CAD/CAM/CNC. Esta metodología parte de las Tomografías Axiales Computarizadas (TAC de la cabeza del paciente, con las cuales se lleva a cabo la reconstrucción tridimensional del cráneo. Luego, en el sistema CAD se reconstruye el implante variando la técnica empleada dependiendo de la región del cráneo con defecto o trauma. Una vez obtenido el modelo, se diseña el montaje y se fabrica el implante con soporte en tecnología CAM/CNC.It’s proposed a methodology in order to design and manufacture cranial implants using DICOM and CAD/CAM/CNC technologies. This methodology begins when the designer makes a three-dimensional cranial reconstruction using the Axial Computer Tomographies (ACT of the patient’s cranium. Next, using a CAD system, the designer rebuilds the implant varying the used technique depending on the affected region. Finally, the designer builds the assembling and manufactures the implant.

  1. Constraining vectors and axial-vectors in walking technicolour by a holographic principle

    DEFF Research Database (Denmark)

    D. Dietrich, Dennis; Kouvaris, Christoforos

    2008-01-01

    We use a holographic principle to study the low-energy spectrum of walking technicolour models. In particular, we predict the masses of the axial vectors as well as the decay constants of vectors and axial vectors as functions of the mass of the techni-rho. Given that there are very few...

  2. Axial offset anomalies and local pH

    International Nuclear Information System (INIS)

    Tarin, F.; Montes, M.; Izquierdo, J.; Garcia-Sanchez, J.

    2001-01-01

    Small radial and axial offset anomalies (AOA) in some Spanish PWR-type NPP's, in addition to the knowledge of the existence of similar anomalies in U.S. PWR's, led us in 1993 to study this problem. Important parameters were correlated for a database of plant operating data consisting of six cycles of five different PWR plants (all of them of the Westinghouse 3-loop, 12 ft., 17 x 17 fuel design). One of these cycles (the oldest one) followed the standard constant pH 308 = 7.0, and the remaining ones followed a modified elevated pH control strategy (the pH at EOC is typically 7.4). Only for the oldest cycle that used the standard pH control was the in-core and ex-core axial offset values found to be in good agreement with the predictions, and an anomalous soluble boron curve behavior not observed. (author)

  3. Axial Ge/Si nanowire heterostructure tunnel FETs

    Energy Technology Data Exchange (ETDEWEB)

    Picraux, Sanuel T [Los Alamos National Laboratory; Daych, Shadi A [Los Alamos National Laboratory

    2010-01-01

    The vapor-liquid-solid (VLS) growth of semiconductor nanowires allows doping and composition modulation along their axis and the realization of axial 1 D heterostructures. This provides additional flexibility in energy band-edge engineering along the transport direction which is difficult to attain by planar materials growth and processing techniques. We report here on the design, growth, fabrication, and characterization of asymmetric heterostructure tunnel field-effect transistors (HTFETs) based on 100% compositionally modulated Si/Ge axial NWs for high on-current operation and low ambipolar transport behavior. We discuss the optimization of band-offsets and Schottky barrier heights for high performance HTFETs and issues surrounding their experimental realization. Our HTFET devices with 10 nm PECVD SiN{sub x} gate dielectric resulted in a measured current drive exceeding 100 {mu}A/{mu}m (I/{pi}D) and 10{sup 5} I{sub on}/I{sub off} ratios.

  4. Elastin Cables Define the Axial Connective Tissue System in the Murine Lung.

    Science.gov (United States)

    Wagner, Willi; Bennett, Robert D; Ackermann, Maximilian; Ysasi, Alexandra B; Belle, Janeil; Valenzuela, Cristian D; Pabst, Andreas; Tsuda, Akira; Konerding, Moritz A; Mentzer, Steven J

    2015-11-01

    The axial connective tissue system is a fiber continuum of the lung that maintains alveolar surface area during changes in lung volume. Although the molecular anatomy of the axial system remains undefined, the fiber continuum of the lung is central to contemporary models of lung micromechanics and alveolar regeneration. To provide a detailed molecular structure of the axial connective tissue system, we examined the extracellular matrix of murine lungs. The lungs were decellularized using a 24 hr detergent treatment protocol. Systematic evaluation of the decellularized lungs demonstrated no residual cellular debris; morphometry demonstrated a mean 39 ± 7% reduction in lung dimensions. Scanning electron microscopy (SEM) demonstrated an intact structural hierarchy within the decellularized lung. Light, fluorescence, and SEM of precision-cut lung slices demonstrated that alveolar duct structure was defined by a cable line element encased in basement membrane. The cable line element arose in the distal airways, passed through septal tips and inserted into neighboring blood vessels and visceral pleura. The ropelike appearance, collagenase resistance and anti-elastin immunostaining indicated that the cable was an elastin macromolecule. Our results indicate that the helical line element of the axial connective tissue system is composed of an elastin cable that not only defines the structure of the alveolar duct, but also integrates the axial connective tissue system into visceral pleura and peripheral blood vessels. © 2015 Wiley Periodicals, Inc.

  5. Effect of bone-soft tissue friction on ultrasound axial shear strain elastography.

    Science.gov (United States)

    Tang, Songyuan; Chaudhry, Anuj; Kim, Namhee; Reddy, J N; Righetti, Raffaella

    2017-07-12

    Bone-soft tissue friction is an important factor affecting several musculoskeletal disorders, frictional syndromes and the ability of a bone fracture to heal. However, this parameter is difficult to determine using non-invasive imaging modalities, especially in clinical settings. Ultrasound axial shear strain elastography is a non-invasive imaging modality that has been used in the recent past to estimate the bonding between different tissue layers. As most elastography methods, axial shear strain elastography is primarily used in soft tissues. More recently, this technique has been proposed to assess the bone-soft tissue interface. In this paper, we investigate the effect of a variation in bone-soft tissue friction coefficient in the resulting axial shear strain elastograms. Finite element poroelastic models of bone specimens exhibiting different bone-soft tissue friction coefficients were created and mechanically analyzed. These models were then imported to an ultrasound elastography simulation module to assess the presence of axial shear strain patterns. In vitro experiments were performed to corroborate selected simulation results. The results of this study show that the normalized axial shear strain estimated at the bone-soft tissue interface is statistically correlated to the bone-soft tissue coefficient of friction. This information may prove useful to better interpret ultrasound elastography results obtained in bone-related applications and, possibly, monitor bone healing.

  6. Deformation and collapse of zircaloy fuel rod cladding into plenum axial gaps

    International Nuclear Information System (INIS)

    Pfennigwerth, P.L.; Gorscak, D.A.; Selsley, I.A.

    1983-01-01

    To minimize support structure, blanket and reflector fuel rods of the thoria urania-fueled Light Water Breeder Reactor (LWBR) were designed with non-freestanding Zircaloy-4 cladding. An analytical model was developed to predict deformation of unirradiated cladding into axial gaps of fuel rod plenum regions where it is unsupported. This model uses the ACCEPT finite element computer program to calculate elastic-plastic deformation of cladding due to external pressure. The finite element is 20-node, triquadratic, isoparametric, and 3-dimensional. Its curved surface permits accurate modeling of the tube geometry, including geometric nonuniformities such as circumferential wall thickness variation and initial tube out-of-roundness. Progressive increases in axial gap length due to cladding elongation and fuel stack shrinkage are modeled, as are deformations of fuel pellets and stainless steel support sleeves which bound plenum axial gaps in LWBR type blanket fuel rods. Zircaloy-4 primary and secondary thermal creep representations were developed from uniaxial creep testing of fuel rod tubing. Creep response to multi-axial loading is modeled with a variation of Hill's formulation for anisotropic materials. Coefficients accounting for anisotropic thermal creep in Zircaloy-4 tubes were developed from creep testing of externally pressurized tubes having fixed axial gaps in the range 2.5 cm to 5.7 cm and radial clearances over simulated fuel pellets ranging from zero to 0.089 mm. (orig./RW)

  7. Comparação morfométrica da orelha interna entre ovinos e humanos através da tomografia computadorizada CT-Scan sheep and human inner ear morphometric comparison

    Directory of Open Access Journals (Sweden)

    Valter Ayres Seibel

    2006-06-01

    Full Text Available INTRODUÇÃO: trabalhos sobre o uso de ovelhas em cirurgias experimentais e treinamento em cirurgia otológica são raros. Este estudo pretende contribuir para ampliar o conhecimento nessa área. OBJETIVO: Estudar a orelha interna da ovelha por meio de tomografia computadorizada e cortes sucessivos com o intuito de apresentar dados morfométricos mais precisos relacionados à comparação entre a orelha de ovelhas e a de humanos. MATERIAL E MÉTODO: Foi realizado um estudo descritivo sem seguimento no qual foram comparadas as estruturas da orelha interna da ovelha com as dos humanos. As medidas foram obtidas através de tomografias computadorizadas e avaliadas por meio de um programa de análise de imagens médicas (Osíris 4.16. RESULTADOS: O estudo morfológico da orelha da ovelha, em média, e da orelha humana, em média, revelaram grande similaridade de anatomia. A maior parte das estruturas (10 de 15 preservou a relação proposta de 2/3 da dimensão humana em relação à dimensão ovina. CONCLUSÃO: Os achados contribuem para uso da orelha da ovelha como modelo em cirurgia experimental e treinamento em cirurgia otológica.INTRODUCTION: Studies about the use of sheep in surgical training and experimental otologic surgery are rare. This study intends to contribute to the knowledge on this field. AIM: To study sheep inner ear structures using computerized tomography and serial cross-sections to collect more accurate morphometric data to compare sheep and human ears. MATERIAL AND METHODS: This descriptive study compared the inner structures of sheep and human ears. Measurements were made using computerized tomography, and they were stored in a DICOM compact disc for later analysis and manipulation, with a program used for medical image analysis (Osíris 4.16. RESULTS: Mean measures for sheep and human ears were found to be similar in this morphological study. Most structures (10 out of 15 maintained the 2/3 ratio of sheep to human ear

  8. Tunable Clamped–Guided Arch Resonators Using Electrostatically Induced Axial Loads

    KAUST Repository

    Alcheikh, Nouha; Ramini, Abdallah; Hafiz, Md Abdullah Al; Younis, Mohammad I.

    2017-01-01

    We present a simulation and experimental investigation of bi-directional tunable in-plane clamped-guided arch microbeam resonators. Tensile and compressive axial forces are generated from a bi-directional electrostatic actuator, which modulates the microbeam stiffness, and hence changes its natural frequency to lower or higher values from its as-fabricated value. Several devices of various anchor designs and geometries are fabricated. We found that for the fabricated shallow arches, the effect of the curvature of the arch is less important compared to the induced axial stress from the axial load. We have shown that the first mode resonance frequency can be increased up to twice its initial value. Additionally, the third mode resonance frequency can be increased up to 30% of its initial value. These results can be promising as a proof-of-concept for the realization of wide-range tunable microresonators. The experimental results have been compared to finite-element simulations, showing good agreement among them.

  9. Axial temperatures and fuel management models for a HTR system

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, U

    1971-11-12

    In the HTR system, there is a large difference in temperature between different parts of the reactor core. The softer neutron spectrum in the upper colder core regions tends to shift the power productions in the fresh fuel upwards. As uranium 235 depletes and plutonium with its higher cross sections in the lower hot regions is built-up, an axial power flattening takes place. These effects have been studied in detail for a single column in an equilibrium environment. The aim of this paper is to relate these findings to a whole reactor core and to investigate the influence of axial temperatures on the overall performance and in particular, the fuel management scheme chosen for the reference design. A further objective has been to calculate the reactivity requirements for different part load conditions and for various daily and weekly load diagrams. As the xenon cross section changes significantly with temperature these investigations are performed for an equilibrium core with due representation of axial temperature zones.

  10. Tunable Clamped–Guided Arch Resonators Using Electrostatically Induced Axial Loads

    KAUST Repository

    Alcheikh, Nouha

    2017-01-04

    We present a simulation and experimental investigation of bi-directional tunable in-plane clamped-guided arch microbeam resonators. Tensile and compressive axial forces are generated from a bi-directional electrostatic actuator, which modulates the microbeam stiffness, and hence changes its natural frequency to lower or higher values from its as-fabricated value. Several devices of various anchor designs and geometries are fabricated. We found that for the fabricated shallow arches, the effect of the curvature of the arch is less important compared to the induced axial stress from the axial load. We have shown that the first mode resonance frequency can be increased up to twice its initial value. Additionally, the third mode resonance frequency can be increased up to 30% of its initial value. These results can be promising as a proof-of-concept for the realization of wide-range tunable microresonators. The experimental results have been compared to finite-element simulations, showing good agreement among them.

  11. Axial sesamoiditis in the horse: A review

    Directory of Open Access Journals (Sweden)

    Christelle Le Roux

    2018-03-01

    Full Text Available Axial sesamoiditis or osteitis of the proximal sesamoid bones (PSBs in the horse is described as a rare condition. The cause remains unknown and speculative, with vascular, infectious, and traumatic aetiologies implicated. It is specifically associated with injury of the palmar or plantar ligament (PL, also known as the intersesamoidean ligament. Imaging findings are generally rewarding and radiological changes are typical, if not pathognomonic, for the condition. Lesions consist of bone lysis at the apical to mid-body axial margins of the PSBs, with variable degrees of joint effusion. Radiographic technique warrants careful attention to make a diagnosis, and exposure factors may need to be adjusted. Perineural, intra-articular and intra-thecal anaesthesia does not seem to provide consistent improvement of lameness in these cases, with literature reporting inconsistent findings. Ultrasonographic findings include digital flexor sheath effusion, loss of the normal fibre structure of the PL at its attachment to the PSBs, abnormal echogenicity or change in thickness of the PL, and irregular hyperechoic cortical margins of the axial margins of the PSBs. Scintigraphy, computed tomography and magnetic resonance imaging, although not necessary to make a diagnosis, may add valuable information regarding the location and extent of lesions. The prognosis remains guarded to poor for return to athletic function. The focus of this paper is a comprehensive review of the proposed aetiopathogenesis of the condition, the prognosis, and a summary of the literature findings with focus on the notable diagnostic imaging features, including radiography, ultrasonography, scintigraphy, computed tomography and magnetic resonance imaging.

  12. Behaviour of a neutral particle with spin in an axial magnetic field

    International Nuclear Information System (INIS)

    Sorokin, S.V.; Ehpp, V.Ya.

    1982-01-01

    Proceeding from the Tamm-Good equation taking into account the spin influence on motion trajectory, the neutral particle motion tracjectory and vector turn of spin polarizition in axial magnetic field have been found. The behaviour of a neutral particle possessing its own magnetic moment in an axially-symmetric stationary magnetic field is considered

  13. Axial-Current Matrix Elements in Light Nuclei from Lattice QCD

    Energy Technology Data Exchange (ETDEWEB)

    Savage, Martin [Univ. of Washington, Seattle, WA (United States); Shanahan, Phiala E. [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Tiburzi, Brian C. [Univ. of Maryland, College Park, MD (United States); Wagman, Michael L. [Univ. of Washington, Seattle, WA (United States); Winter, Frank T. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Beane, Silas [Univ. of New Hampshire, Durham, NH (United States); Chang, Emmanuel [Univ. of Washington, Seattle, WA (United States); Davoudi, Zohreh; Detmold, William [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Orginos, Konstantinos [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); College of William and Mary, Williamsburg, VA (United States)

    2016-12-01

    I present results from the first lattice QCD calculations of axial-current matrix elements in light nuclei, performed by the NPLQCD collaboration. Precision calculations of these matrix elements, and the subsequent extraction of multi-nucleon axial-current operators, are essential in refining theoretical predictions of the proton-proton fusion cross section, neutrino-nucleus cross sections and $\\beta\\beta$-decay rates of nuclei. In addition, they are expected to shed light on the phenomenological quenching of $g_A$ that is required in nuclear many-body calculations.

  14. Extended Hamiltonian formalism of the pure space-like axial gauge Schwinger model

    International Nuclear Information System (INIS)

    Nakawaki, Yuji; Mccartor, Gary

    2001-01-01

    We demonstrate that pure space-like axial gauge quantizations of gauge fields can be constructed in ways that are free from infrared divergences. To do so, we must extend the Hamiltonian formalism to include residual gauge fields. We construct an operator solution and an extended Hamiltonian of the pure space-like axial gauge Schwinger model. We begin by constructing an axial gauge formation in auxiliary coordinates, x μ =(x + , x - ), where x + =x 0 sinθ + x 1 cosθ, x - =x 0 cosθ - x 1 sinθ, and we take A=A 0 cosθ + A 1 sin θ=0 as the gauge fixing condition. In the region 0 - as the evolution parameter and construct a traditional canonical formulation of the temporal gauge Schwinger model in which residual gauge fields dependent only on x + are static canonical variables. Then we extrapolate the temporal gauge operator solution into the axial region, π / 4 + is taken as the evolution parameter. In the axial region we find that we have to take the representation of the residual gauge fields realizing the Mandelstam-Leibbrandt prescription in order for the infrared divergences resulting from (∂) -1 to be canceled by corresponding ones resulting from the inverse of the hyperbolic Laplace operator. We overcome the difficulty of constructing the Hamiltonian for the residual gauge fields by employing McCartor and Robertson's method, which gives us a term integrated over x - =constant. Finally, by taking the limit θ→π / 2 - 0, we obtain an operator solution and the Hamiltonian of the axial gauge (Coulomb gauge) Schwinger model in ordinary coordinates. That solution includes auxiliary fields, and the representation space is of indefinite metric, providing further evidence that 'physical' gauges are no more physical than 'unphysical' gauges. (author)

  15. Factors related to axial length elongation and myopia progression in orthokeratology practice.

    Directory of Open Access Journals (Sweden)

    Bingjie Wang

    Full Text Available To investigate which baseline factors are predictive for axial length growth over an average period of 2.5 years in a group of children wearing orthokeratology (OK contact lenses.In this retrospective study, the clinical records of 249 new OK wearers between January 2012 and December 2013 from the contact lens clinic at the Eye and ENT Hospital of Fudan University were reviewed. The primary outcome measure was axial length change from baseline to the time of review (July-August 2015. Independent variables included baseline measures of age at initiation of OK wear, gender, refractive error (spherical equivalent, astigmatism, average keratometry, corneal toricity, central corneal thickness, white-to-white corneal diameter, pupil size, corneal topography eccentricity value (e-value, intraocular pressure (IOP and total time in follow-up (months total. The contributions of all independent variables on axial length change at the time of review were assessed using univariate and multivariable regression analyses.Univariate analyses of the right eyes of 249 OK patients showed that smaller increases in axial length were associated with older age at the onset of OK lens wear, greater baseline spherical equivalent myopic refractive error, less time in follow-up and a smaller e-value. Multivariable analyses of the significant right eye variables showed that the factors associated with smaller axial length growth were older age at the onset of OK lens wear (p<0.0001, greater baseline spherical equivalent myopic refractive error (p = 0.0046 and less time in follow-up (p<0.0001.The baseline factors demonstrating the greatest correlation with reduced axial length elongation during OK lens wear in myopic children included greater baseline spherical equivalent myopic refractive error and older age at the onset of OK lens wear.

  16. Fundamental metallurgical aspects of axial splitting in zircaloy cladding

    International Nuclear Information System (INIS)

    Chung, H. M.

    2000-01-01

    Fundamental metallurgical aspects of axial splitting in irradiated Zircaloy cladding have been investigated by microstructural characterization and analytical modeling, with emphasis on application of the results to understand high-burnup fuel failure under RIA situations. Optical microscopy, SEM, and TEM were conducted on BWR and PWR fuel cladding tubes that were irradiated to fluence levels of 3.3 x 10 21 n cm -2 to 5.9 x 10 21 n cm -2 (E > 1 MeV) and tested in hot cell at 292--325 C in Ar. The morphology, distribution, and habit planes of macroscopic and microscopic hydrides in as-irradiated and posttest cladding were determined by stereo-TEM. The type and magnitude of the residual stress produced in association with oxide-layer growth and dense hydride precipitation, and several synergistic factors that strongly influence axial-splitting behavior were analyzed. The results of the microstructural characterization and stress analyses were then correlated with axial-splitting behavior of high-burnup PWR cladding reported for simulated-RIA conditions. The effects of key test procedures and their implications for the interpretation of RIA test results are discussed

  17. CT Assessment of the axial deviation of the femoral and tibial prosthetic components in total knee arthroplasty; Valutazione con Tomografia Computerizzata della rotazione delle componenti femorale e tibiale nell'artroprotesi totale del ginocchio

    Energy Technology Data Exchange (ETDEWEB)

    Rimondi, E.; Molinari, M.; Moio, A.; Busacca, M. [Istituto Ortopedico Rizzoli, Bologna (Italy). Servizio di Diagnostica per Immagini; Trentani, F.; Trentani, P.; Tigani, D. [Istituto Ortopedico Rizzoli, Bologna (Italy). VII Div.; Nigrosoli, M. [Istituto Ortopedico Rizzoli, Bologna (Italy). IV Div.

    2000-06-01

    CT assessment of the axial deviation of the femoral and tibial prosthetic components in total knee arthroplasty. From January to July 1999, 17 patients, 10 males and 7 females, mean age 66 years (standard deviation plus or minus 4) were examined after total knee arthroplasty. Exclusion criteria were prosthesis loosening and severe (equal or superior to 7 degrees) varus o valgus deviation. All patients were examined with knee radiography in the standing position completed by axial projection of patella and by CT scanning. It was used a modification of Berger technique and carried out comparative CT scans extended lower limbs and acquisitions perpendicular to the mechanical axis of the knee, from the femoral supracondylar region down to the plane crossing the distal end of the tibial prosthetic component. Reference lines were then drawn electronically on given scanning planes to reckon the axial deviation of the femoral and tibial prosthetic components. Six patients, one female and 5 males with normal rotational values of femoral and tibial prosthetic components presented no clinical symptoms. Eight patients, 4 females and 4 males, with abnormal values presented the following clinical symptoms: medial impingement, (incomplete) dislocation patella, and lateral instability. One female patient with a normal rotational value of femoral prosthetic component and an altered value of tibial prosthetic component presented medial impingement. Finally two patients, one female and one male, were absolutely asymptomatic although the rotational values of the two prosthetic components were beyond the normal range. Total knee arthroplasty is presently a standard treatment for many conditions involving this joint. There are several possible postoperative complications, namely fractures, dislocations (a)septic losening and femoropatellar instability. The latter condition is the most frequent complication among implant failures and is caused by bad orientation of the femoral and tibial

  18. Metamorphosis of helical magnetorotational instability in the presence of axial electric current.

    Science.gov (United States)

    Priede, Jānis

    2015-03-01

    This paper presents numerical linear stability analysis of a cylindrical Taylor-Couette flow of liquid metal carrying axial electric current in a generally helical external magnetic field. Axially symmetric disturbances are considered in the inductionless approximation corresponding to zero magnetic Prandtl number. Axial symmetry allows us to reveal an entirely new electromagnetic instability. First, we show that the electric current passing through the liquid can extend the range of helical magnetorotational instability (HMRI) indefinitely by transforming it into a purely electromagnetic instability. Two different electromagnetic instability mechanisms are identified. The first is an internal pinch-type instability, which is due to the interaction of the electric current with its own magnetic field. Axisymmetric mode of this instability requires a free-space component of the azimuthal magnetic field. When the azimuthal component of the magnetic field is purely rotational and the axial component is nonzero, a new kind of electromagnetic instability emerges. The latter, driven by the interaction of electric current with a weak collinear magnetic field in a quiescent fluid, gives rise to a steady meridional circulation coupled with azimuthal rotation.

  19. Characterization of fluid forces exerted on a cylinder array oscillating laterally in axial flow

    International Nuclear Information System (INIS)

    Divaret, Lise

    2014-01-01

    This thesis presents an experimental and a numerical study of the fluid forces exerted on a cylinder or a cylinder array oscillating laterally in an axial flow. The parameters of the system are the amplitude, the oscillation frequency, the confinement and the length to diameter ratio of the cylinder. The objective is to determine the fluid damping created by the axial flow, i.e. the dissipative force. The industrial application of this thesis is the determination of the fluid damping of the fuel assemblies in the core of a nuclear power plant during an earthquake. The study focuses on the configurations where the oscillation velocity is small compared to the axial flow velocity. In a first part, we study the case of a cylinder with no confinement oscillating in axial flow. Two methods are used: a dynamical and a quasi-static approach. In dynamics, the damping rate is measured during free oscillations of the cylinder. In the quasi-static approach, the damping coefficient is calculated from the normal force measured on a yawed cylinder. The range of the small ratios between the oscillation and the axial flow velocities corresponds to a range of low yaw angle where the cylinder is in near-axial flow in statics. The case of a yawed cylinder has been studied both experimentally with experiments in a wind tunnel and numerically with CFD calculations. The analyses of the fluid forces shows that for yaw angles smaller than 5 degrees, a linear lift with the yaw angle creates the damping. The origin of the lift force is discussed from pressure and velocity measurements. The results of the quasi-static approach are compared to the results of the dynamical experiments. In a second part, an experimental study is performed on a rigid cylinder array made up of 40 cylinders oscillating in an axial flow. The normal force and the displacement of the cylinder array are measured simultaneously. The added mass and damping coefficient are calculated and their variation with the

  20. Magnetic uni- and tri-axial grain-orientation in superconductors with layered structures

    International Nuclear Information System (INIS)

    Horii, S.; Yamaki, M.; Ogino, H.; Maeda, T.; Shimoyama, J.

    2010-01-01

    We report the grain-orientation effects under a modulated rotation magnetic field for Y-based cuprate superconductors and LaFeAsO (La1111). Tri-axial orientation has been successfully achieved only for orthorhombic Y 2 Ba 4 Cu 7 O y and YBa 2 Cu 4 O 8 powders without a twin microstructure, while separation of three crystallographic axes could not be observed in twinned YBa 2 Cu 3 O y (Y123) and tetragonal La1111 powders. The morphology of grains, in addition to the symmetry of crystal structures, seriously affects the degrees of tri-axial orientation, which means that the control of twin microstructures is required for the tri-axial magnetic orientation in Y123.

  1. Numerical Simulation of single-stage axial fan operation under dusty flow conditions

    Science.gov (United States)

    Minkov, L. L.; Pikushchak, E. V.

    2017-11-01

    Assessment of the aerodynamic efficiency of the single-stage axial flow fan under dusty flow conditions based on a numerical simulation using the computational package Ansys-Fluent is proposed. The influence of dust volume fraction on the dependences of the air volume flow rate and the pressure drop on the rotational speed of rotor is demonstrated. Matching functions for formulas describing a pressure drop and volume flow rate in dependence on the rotor speed and dust content are obtained by numerical simulation for the single-stage axial fan. It is shown that the aerodynamic efficiency of the single-stage axial flow fan decreases exponentially with increasing volume content of dust in the air.

  2. Axial complex and associated structures of the sea urchin Strongylocentrotus pallidus (Sars, G.O. 1871) (Echinodermata: Echinoidea).

    Science.gov (United States)

    Ezhova, Olga Vladimirovna; Malakhov, Vladimir Vasil'yevich; Egorova, Ekaterina Alekseevna

    2018-06-01

    Studies of echinoid microscopic anatomy over the last two centuries have created a number of inaccuracies and mistakes that have accumulated in the descriptions of the intricate organization of the coelomic system of Echinoidea. To clarify the situation, we reconstructed the axial complex and radial complex of the echinoid Strongylocentrotus pallidus. The water ring is located between the perivisceral coelom and the perioral coelom. The oral haemal ring lies between the coelothelia of the water-vascular, perivisceral, and perioral rings. The axial part of the axial organ communicates with the oral haemal ring in interradius CD, but the axial coelom does not form the axocoelomic perihaemal ring. The ventral intestinal haemal vessel originates from the oral haemal ring in radius A, and then branches into a network of capillaries, from which the dorsal intestinal vessel starts. The pericardial coelom envelopes the pericardial part of the axial organ, the lacunae of which communicate with the haemocoel of the body wall and with the axial part of the axial organ. The genital haemal ring and the dorsal intestinal vessel communicate with the axial organ. The genital coelom passes in the CD interradius on the side opposite to the hindgut. There is a somatocoelomic perihaemal ring, which sends a pair of coelomic outgrowths into each radius, accompanied by a radial haemal vessel in the oral part. The mistakes and inaccuracies of early descriptions of the echinoid axial complex are listed. The axial complex and associated structures of sea urchins are compared with other eleutherozoans. © 2018 Wiley Periodicals, Inc.

  3. Empirical correlations for axial dispersion coefficient and Peclet number in fixed-bed columns.

    Science.gov (United States)

    Rastegar, Seyed Omid; Gu, Tingyue

    2017-03-24

    In this work, a new correlation for the axial dispersion coefficient was obtained using experimental data in the literature for axial dispersion in fixed-bed columns packed with particles. The Chung and Wen correlation, the De Ligny correlation are two popular empirical correlations. However, the former lacks the molecular diffusion term and the latter does not consider bed voidage. The new axial dispersion coefficient correlation in this work was based on additional experimental data in the literature by considering both molecular diffusion and bed voidage. It is more comprehensive and accurate. The Peclet number correlation from the new axial dispersion coefficient correlation on the average leads to 12% lower Peclet number values compared to the values from the Chung and Wen correlation, and in many cases much smaller than those from the De Ligny correlation. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Study of Fuel Rods Axial Enrichment Distribution Effect on the Neutronic Parameters of the Reactor Core

    International Nuclear Information System (INIS)

    Pazirandeh, A.; Nasiri, S. H.

    2012-01-01

    Optimization of the fuel burn up is an important issue in nuclear reactor fuel management and technology. Radial enrichment distribution in the reactor core is a conventional method and axial enrichment is constant along the fuel rod. In this article, the effects of axial enrichment distribution variation on neutronic parameters of PWR core are studied. The axial length of the core is divided into ten sections, considering axial enrichment variation and leaving the existing radial enrichment distribution intact. This study shows that the radial and axial power peaking factors are decreased as compared with the typical conventional core. In addition, the first core lifetime lasts 30 days longer than normal PWR core. Moreover, at the same time boric acid density is 0.2 g/kg at the beginning of the cycle. The flux shape is also flat at the beginning of the cycle for the proposed configuration of the axially enrichment distribution.

  5. Elevated temperature axial and torsional fatigue behavior of Haynes 188

    Science.gov (United States)

    Bonacuse, Peter J.; Kalluri, Sreeramesh

    1992-06-01

    The results of high-temperature axial and torsional low-cycle fatigue experiments performed on Haynes 188, a wrought cobalt-base superalloy, are reported. Fatigue tests were performed at 760 C in air on thin-walled tubular specimens at various ranges under strain control. Data are also presented for coefficient of thermal expansion, elastic modulus, and shear modulus at various temperatures from room to 1000 C, and monotonic and cyclic stress-strain curves in tension and in shear at 760 C. The data set is used to evaluate several multiaxial fatigue life models (most were originally developed for room temperature multiaxial life prediction) including von Mises equivalent strain range (ASME boiler and pressure vessel code), Manson-Halford, Modified Multiaxiality Factor (proposed here), Modified Smith-Watson-Topper, and Fatemi-Socie-Kurath. At von Mises equivalent strain ranges (the torsional strain range divided by the square root of 3, taking the Poisson's ratio to be 0.5), torsionally strained specimens lasted, on average, factors of 2 to 3 times longer than axially strained specimens. The Modified Multiaxiality Factor approach shows promise as a useful method of estimating torsional fatigue life from axial fatigue data at high temperatures. Several difficulties arose with the specimen geometry and extensometry used in these experiments. Cracking at extensometer probe indentations was a problem at smaller strain ranges. Also, as the largest axial and torsional strain range fatigue tests neared completion, a small amount of specimen buckling was observed.

  6. Self-referenced axial chromatic dispersion measurement in multiphoton microscopy through 2-color THG imaging.

    Science.gov (United States)

    Du, Yu; Zhuang, Ziwei; He, Jiexing; Liu, Hongji; Qiu, Ping; Wang, Ke

    2018-05-16

    With tunable excitation light, multiphoton microscopy (MPM) is widely used for imaging biological structures at subcellular resolution. Axial chromatic dispersion, present in virtually every transmissive optical system including the multiphoton microscope, leads to focal (and the resultant image) plane separation. Here we demonstrate experimentally a technique to measure the axial chromatic dispersion in a multiphoton microscope, using simultaneous 2-color third-harmonic generation (THG) imaging excited by a 2-color soliton source with tunable wavelength separation. Our technique is self-referenced, eliminating potential measurement error when 1-color tunable excitation light is used which necessitates reciprocating motion of the mechanical translation stage. Using this technique, we demonstrate measured axial chromatic dispersion with 2 different objective lenses in a multiphoton microscope. Further measurement in a biological sample also indicates that this axial chromatic dispersion, in combination with 2-color imaging, may open up opportunity for simultaneous imaging of two different axial planes. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  7. Upregulation of matrix synthesis in chondrocyte-seeded agarose following sustained bi-axial cyclic loading

    Directory of Open Access Journals (Sweden)

    Belinda Pingguan-Murphy

    2012-08-01

    Full Text Available OBJECTIVES: The promotion of extracellular matrix synthesis by chondrocytes is a requisite part of an effective cartilage tissue engineering strategy. The aim of this in vitro study was to determine the effect of bi-axial cyclic mechanical loading on cell proliferation and the synthesis of glycosaminoglycans by chondrocytes in threedimensional cultures. METHOD: A strain comprising 10% direct compression and 1% compressive shear was applied to bovine chondrocytes seeded in an agarose gel during two 12-hour conditioning periods separated by a 12-hour resting period. RESULTS: The bi-axial-loaded chondrocytes demonstrated a significant increase in glycosaminoglycan synthesis compared with samples exposed to uni-axial or no loading over the same period (p<0.05. The use of a free-swelling recovery period prior to the loading regime resulted in additional glycosaminoglycan production and a significant increase in DNA content (p<0.05, indicating cell proliferation. CONCLUSIONS: These results demonstrate that the use of a bi-axial loading regime results in increased matrix production compared with uni-axial loading.

  8. ZZ PWR-AXBUPRO-GKN, Measured Axial Burnup Profiles, NPP Neckarewstheim

    International Nuclear Information System (INIS)

    Neuber, Jens-Christian; Lamprecht, Thomas

    1999-01-01

    Description or function: PWR-AXBUPRO-GKN12 contains Axial Burnup Shapes released by Siemens AG Power Generation Group. It contains data sets relative to following NPP and initial enrichment: - NPP Neckarwestheim 1, Fuel assemblies with an initial enrichment of 3.5 wt.-% 235-U; - NPP Neckarwestheim 2, Fuel assemblies with an initial enrichment of 3.5 wt.-% 235-U; - NPP Neckarwestheim 2, Fuel assemblies with an initial enrichment of 3.8 wt.-% 235-U; - NPP Neckarwestheim 2, Fuel assemblies with an initial enrichment of 4.0 wt.-% 235-U. In each of these files the axial shapes are listed one after the other. Each shape is characterised by: - the number of the cycle; - the number of the fuel assembly. - axial burnup shape characteristics: - height (in centimeter) of the nodes with respect to the active length of the fuel assemblies normalized to the cold, unirradiated state. - the nodal burnup (in MWd/kg U). - fuel assembly design data as well as core geometry and operating data pertinent to depletion calculations: NPP Neckarwestheim 1 (GKN1) - (square pitch lattice 15X15 - thermal Power 2497 MW)thermal Power 2497 MW); More than 700 EOC axial shapes from cycle 18 up. From cycle 18 to cycle 20 a change from an Out-In-Loading to an In-Out-Loading has taken place. Fuel assemblies up to number 1093 have spacer grids made of Inconel, whereas all the fuel assemblies from number 1094 up have spacer grids made of Zircaloy. Discharge burnups range from: 9.7 to 52.8 MWd/kg. NPP Neckarwestheim 2 (GKN2) - (square pitch lattice 18X18 - thermal Power 3850 MW) more than 500 EOC axial shapes from cycle 5 up: - More than 170 shapes for an initial fuel enrichment of 3.5 wt.-% 235-U, discharge burnup ranges from 16.3 to 44.4 MWd/kg; - more than 170 shapes for an initial fuel enrichment of 3.8 wt.-% 235-U, discharge burnup ranges from 14.0 to 52.8 MWd/kg; - more than 180 shapes for an initial fuel enrichment of 4.0 wt.-% 235-U. discharge burnup ranges from 15.5 to 48.9 MWd/kg. PWR AXBUPRO

  9. Axial mercury segregation in direct current operated low-pressure argon-mercury gas discharge: Part I. Experimental

    NARCIS (Netherlands)

    Gielen, J.W.A.M.; de Groot, S.; Dijk, van J.; Mullen, van der J.J.A.M.

    2004-01-01

    Due to cataphoresis, axial segregation of mercury will occur when the gas discharge of a fluorescent lamp is operated by means of a direct current. A consequence of this is a non-uniform axial luminance distribution along the lamp. To determine the degree of axial mercury segregation experimentally,

  10. Theoretical analysis to investigate thermal performance of co-axial heat pipe solar collector

    Science.gov (United States)

    Azad, E.

    2011-12-01

    The thermal performance of co-axial heat pipe solar collector which consist of a collector 15 co-axial heat pipes surrounded by a transparent envelope and which heat a fluid flowing through the condenser tubes have been predicted using heat transfer analytical methods. The analysis considers conductive and convective losses and energy transferred to a fluid flowing through the collector condenser tubes. The thermal performances of co-axial heat pipe solar collector is developed and are used to determine the collector efficiency, which is defined as the ratio of heat taken from the water flowing in the condenser tube and the solar radiation striking the collector absorber. The theoretical water outlet temperature and efficiency are compared with experimental results and it shows good agreement between them. The main advantage of this collector is that inclination of collector does not have influence on performance of co-axial heat pipe solar collector therefore it can be positioned at any angle from horizontal to vertical. In high building where the roof area is not enough the co-axial heat pipe solar collectors can be installed on the roof as well as wall of the building. The other advantage is each heat pipe can be topologically disconnected from the manifold.

  11. Theoretical analysis to investigate thermal performance of co-axial heat pipe solar collector

    Energy Technology Data Exchange (ETDEWEB)

    Azad, E. [Iranian Research Organization for Science and Technology (IROST), Advanced Materials and Renewable Energy Department, Tehran (Iran, Islamic Republic of)

    2011-12-15

    The thermal performance of co-axial heat pipe solar collector which consist of a collector 15 co-axial heat pipes surrounded by a transparent envelope and which heat a fluid flowing through the condenser tubes have been predicted using heat transfer analytical methods. The analysis considers conductive and convective losses and energy transferred to a fluid flowing through the collector condenser tubes. The thermal performances of co-axial heat pipe solar collector is developed and are used to determine the collector efficiency, which is defined as the ratio of heat taken from the water flowing in the condenser tube and the solar radiation striking the collector absorber. The theoretical water outlet temperature and efficiency are compared with experimental results and it shows good agreement between them. The main advantage of this collector is that inclination of collector does not have influence on performance of co-axial heat pipe solar collector therefore it can be positioned at any angle from horizontal to vertical. In high building where the roof area is not enough the co-axial heat pipe solar collectors can be installed on the roof as well as wall of the building. The other advantage is each heat pipe can be topologically disconnected from the manifold. (orig.)

  12. High-energy manifestations of heavy quarks in axial-vector neutral currents

    International Nuclear Information System (INIS)

    Kizukuri, Y.; Ohba, I.; Okano, K.; Yamanaka, Y.

    1981-01-01

    A recent work by Collins, Wilczek, and Zee has attempted to manifest the incompleteness of the decoupling theorem in the axial-vector neutral currents at low energies. In the spirit of their work, we calculate corrections of the axial-vector neutral currents by virtual-heavy-quark exchange in the high-energy e + e - processes and estimate some observable quantities sensitive to virtual-heavy-quark masses which may be compared with experimental data at LEP energies

  13. Signal-to-noise ratio, contrast-to-noise ratio and their trade-offs with resolution in axial-shear strain elastography

    International Nuclear Information System (INIS)

    Thitaikumar, Arun; Krouskop, Thomas A; Ophir, Jonathan

    2007-01-01

    In axial-shear strain elastography, the local axial-shear strain resulting from the application of quasi-static axial compression to an inhomogeneous material is imaged. In this paper, we investigated the image quality of the axial-shear strain estimates in terms of the signal-to-noise ratio (SNR asse ) and contrast-to-noise ratio (CNR asse ) using simulations and experiments. Specifically, we investigated the influence of the system parameters (beamwidth, transducer element pitch and bandwidth), signal processing parameters (correlation window length and axial window shift) and mechanical parameters (Young's modulus contrast, applied axial strain) on the SNR asse and CNR asse . The results of the study show that the CNR asse (SNR asse ) is maximum for axial-shear strain values in the range of 0.005-0.03. For the inclusion/background modulus contrast range considered in this study ( asse (SNR asse ) is maximum for applied axial compressive strain values in the range of 0.005%-0.03%. This suggests that the RF data acquired during axial elastography can be used to obtain axial-shear strain elastograms, since this range is typically used in axial elastography as well. The CNR asse (SNR asse ) remains almost constant with an increase in the beamwidth while it increases as the pitch increases. As expected, the axial shift had only a weak influence on the CNR asse (SNR asse ) of the axial-shear strain estimates. We observed that the differential estimates of the axial-shear strain involve a trade-off between the CNR asse (SNR asse ) and the spatial resolution only with respect to pitch and not with respect to signal processing parameters. Simulation studies were performed to confirm such an observation. The results demonstrate a trade-off between CNR asse and the resolution with respect to pitch

  14. Multi-axial response of idealized cermets

    International Nuclear Information System (INIS)

    Pickering, E.G.; Bele, E.; Deshpande, V.S.

    2016-01-01

    The yield response of two idealized cermets comprising mono and bi-disperse steel spheres in a Sn/Pb solder matrix has been investigated for a range of axisymmetric stress states. Proportional stress path experiments are reported, from which are extracted the initial yield surfaces and their evolution with increasing plastic strain. The initial yield strength is nearly independent of the hydrostatic pressure but the strain hardening rate increases with stress triaxiality up to a critical value. For higher triaxialities, the responses are independent of hydrostatic pressure. Multi-axial measurements along with X-ray tomography were used to demonstrate that the deformation of these idealized cermets occurs by two competing mechanisms: (i) a granular flow mechanism that operates at low levels of triaxiality, where volumetric dilation occurs under compressive stress states, and (ii) a plastically incompressible mechanism that operates at high stress triaxialities. A phenomenological viscoplastic constitutive model that incorporates both deformation mechanisms is presented. While such multi-axial measurements are difficult for commercial cermets with yield strengths on the order of a few GPa, the form of their constitutive relation is expected to be similar to that of the idealized cermets presented here.

  15. Anion-π Catalysts with Axial Chirality.

    Science.gov (United States)

    Wang, Chao; Matile, Stefan

    2017-09-04

    The idea of anion-π catalysis is to stabilize anionic transition states by anion-π interactions on aromatic surfaces. For asymmetric anion-π catalysis, π-acidic surfaces have been surrounded with stereogenic centers. This manuscript introduces the first anion-π catalysts that operate with axial chirality. Bifunctional catalysts with tertiary amine bases next to π-acidic naphthalenediimide planes are equipped with a bulky aromatic substituent in the imide position to produce separable atropisomers. The addition of malonic acid half thioesters to enolate acceptors is used for evaluation. In the presence of a chiral axis, the selective acceleration of the disfavored but relevant enolate addition was much better than with point chirality, and enantioselectivity could be observed for the first time for this reaction with small-molecule anion-π catalysts. Enantioselectivity increased with the π acidity of the π surface, whereas the addition of stereogenic centers around the aromatic plane did not cause further improvements. These results identify axial chirality of the active aromatic plane generated by atropisomerism as an attractive strategy for asymmetric anion-π catalysis. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Axial SPN and radial MOC coupled whole core transport calculation

    International Nuclear Information System (INIS)

    Cho, Jin-Young; Kim, Kang-Seog; Lee, Chung-Chan; Zee, Sung-Quun; Joo, Han-Gyu

    2007-01-01

    The Simplified P N (SP N ) method is applied to the axial solution of the two-dimensional (2-D) method of characteristics (MOC) solution based whole core transport calculation. A sub-plane scheme and the nodal expansion method (NEM) are employed for the solution of the one-dimensional (1-D) SP N equations involving a radial transverse leakage. The SP N solver replaces the axial diffusion solver of the DeCART direct whole core transport code to provide more accurate, transport theory based axial solutions. In the sub-plane scheme, the radial equivalent homogenization parameters generated by the local MOC for a thick plane are assigned to the multiple finer planes in the subsequent global three-dimensional (3-D) coarse mesh finite difference (CMFD) calculation in which the NEM is employed for the axial solution. The sub-plane scheme induces a much less nodal error while having little impact on the axial leakage representation of the radial MOC calculation. The performance of the sub-plane scheme and SP N nodal transport solver is examined by solving a set of demonstrative problems and the C5G7MOX 3-D extension benchmark problems. It is shown in the demonstrative problems that the nodal error reaching upto 1,400 pcm in a rodded case is reduced to 10 pcm by introducing 10 sub-planes per MOC plane and the transport error is reduced from about 150 pcm to 10 pcm by using SP 3 . Also it is observed, in the C5G7MOX rodded configuration B problem, that the eigenvalues and pin power errors of 180 pcm and 2.2% of the 10 sub-planes diffusion case are reduced to 40 pcm and 1.4%, respectively, for SP 3 with only about a 15% increase in the computing time. It is shown that the SP 5 case gives very similar results to the SP 3 case. (author)

  17. Non-Euclidean stress-free configuration of arteries accounting for curl of axial strips sectioned from vessels.

    Science.gov (United States)

    Takamizawa, Keiichi; Nakayama, Yasuhide

    2013-11-01

    It is well known that arteries are subject to residual stress. In earlier studies, the residual stress in the arterial ring relieved by a radial cut was considered in stress analysis. However, it has been found that axial strips sectioned from arteries also curled into arcs, showing that the axial residual stresses were relieved from the arterial walls. The combined relief of circumferential and axial residual stresses must be considered to accurately analyze stress and strain distributions under physiological loading conditions. In the present study, a mathematical model of a stress-free configuration of artery was proposed using Riemannian geometry. Stress analysis for arterial walls under unloaded and physiologically loaded conditions was performed using exponential strain energy functions for porcine and human common carotid arteries. In the porcine artery, the circumferential stress distribution under physiological loading became uniform compared with that without axial residual strain, whereas a gradient of axial stress distribution increased through the wall thickness. This behavior showed almost the same pattern that was observed in a recent study in which approximate analysis accounting for circumferential and axial residual strains was performed, whereas the circumferential and axial stresses increased from the inner surface to the outer surface under a physiological condition in the human common carotid artery of a two-layer model based on data of other recent studies. In both analyses, Riemannian geometry was appropriate to define the stress-free configurations of the arterial walls with both circumferential and axial residual strains.

  18. Axial crystals macroscopic symmetry and tensor properties

    Czech Academy of Sciences Publication Activity Database

    Janovec, Václav

    2017-01-01

    Roč. 90, č. 1 (2017), s. 1-10 ISSN 0141-1594 Institutional support: RVO:68378271 Keywords : axial * polar * pseudopolar * chiral * enantiomorphism * optical activity Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 1.060, year: 2016

  19. Quando a fase de equilíbrio pode ser suprimida nos exames de tomografia computadorizada de abdome? What is the real role of the equilibrium phase in abdominal computed tomography?

    Directory of Open Access Journals (Sweden)

    Priscila Silveira Salvadori

    2013-04-01

    Full Text Available OBJETIVO: Avaliar a necessidade de realização da fase de equilíbrio nos exames de tomografia computadorizada de abdome. MATERIAIS E MÉTODOS: Realizou-se estudo retrospectivo, transversal e observacional, avaliando 219 exames consecutivos de tomografia computadorizada de abdome com contraste intravenoso, realizados num período de três meses, com diversas indicações clínicas. Para cada exame foram emitidos dois pareceres, um avaliando o exame sem a fase de equilíbrio (primeira análise e o outro avaliando todas as fases em conjunto (segunda análise. Ao final de cada avaliação, foi estabelecido se houve mudança nos diagnósticos principais e secundários, entre a primeira e a segunda análise. Foi utilizada a extensão do teste exato de Fisher para avaliar a modificação dos diagnósticos principais (p 0,999. Com relação aos diagnósticos secundários, cinco exames (2,3% foram modificados. CONCLUSÃO: Para indicações clínicas como estadiamento tumoral, abdome agudo e pesquisa de coleção abdominal, a fase de equilíbrio não acrescenta contribuição diagnóstica expressiva, podendo ser suprimida dos protocolos de exame.OBJECTIVE: To evaluate the role of the equilibrium phase in abdominal computed tomography. MATERIALS AND METHODS: A retrospective, cross-sectional, observational study reviewed 219 consecutive contrast-enhanced abdominal computed tomography images acquired in a three-month period, for different clinical indications. For each study, two reports were issued - one based on the initial analysis of non-contrast-enhanced, arterial and portal phases only (first analysis, and a second reading of these phases added to the equilibrium phase (second analysis. At the end of both readings, differences between primary and secondary diagnoses were pointed out and recorded, in order to measure the impact of suppressing the equilibrium phase on the clinical outcome for each of the patients. The extension of the exact Fisher

  20. The role of an axial MR scan on the diagnosis a meniscal tear of the knee joint

    International Nuclear Information System (INIS)

    Yeom, Suk Keu; Kim, Baek Hyun; Hong, Suk Joo; Seol, Hae Young

    2007-01-01

    To evaluate the role of standard axial MR images for the diagnosis for meniscal tears of the knee. Forty-five patients with a prior MRI examination that underwent arthroscopic surgery of the knee due to clinical impression of a meniscal tear were included in the study group. The sequence for meniscal evaluation was an axial fat-saturated proton density-weighted image with a 4 mm slice thickness. Axial MR images were independently reviewed by two radiologists and were compared with findings of arthroscopy. The sensitivity, specificity, positive predictive value, negative predictive value and accuracy of the axial MR scan for the diagnosis of the meniscal tear were calculated. A total 90 menisci of 45 patients were evaluated in the axial MR scans. Forty-two patients had meniscal tears, and two of the patients had tears in both menisci; thus, a total of 44 meniscal tears were found by arthroscopy. For meniscal tears, the sensitivity of the axial plane was 76.2%, the specificity was 89.1% and the accuracy was 81.1%. False negative meniscal tears were seen in 12 cases and false positive meniscal tears were seen in 5 cases on the axial MR images. In standard knee MRI examinations, axial images may be valuable for the detection and localization of meniscal tears

  1. Avaliação de seis anos de fraturas cervicais subaxiais Evaluación de seis años de fracturas cervicales subaxiales Evaluation of six years of cervical sub-axial fractures

    Directory of Open Access Journals (Sweden)

    Leonardo Franco Pinheiro Gaia

    2013-01-01

    ón (AO. Se utilizaron radiografías en las incidencias frontal y lateral y tomografía computarizada, para dividir las fracturas en A (compresión, B (distracción y C (rotación, de acuerdo con el patrón de presentación. Se analizaron los siguientes parámetros: sexo, edad, clasificación AO, mecanismo de trauma, presencia de déficit neurológico y tratamiento quirúrgico o conservador. RESULTADOS: Fueron analizadas 264 historias clínicas, siendo 216 pacientes hombres e 48 mujeres. La media de edad de éstos pacientes fue de 38,55 años. El mecanismo de trauma más común de las fracturas cervicales subaxiales fue el accidente automovilístico, con 84 casos. En cuanto al tipo de fractura según la clasificación AO, la más frecuente fue el tipo B. De los casos evaluados, 136 pacientes presentaron déficit neurológico parcial o completo. El tratamiento quirúrgico fue realizado en 166 casos. CONCLUSIÓN: Queda claro que las fracturas cervicales representan un importante problema para la salud pública y privada en Brasil. La prevención de fracturas cervicales presenta la mejor relación costo beneficio en el abordaje de éstas lesiones.OBJECTIVE: Retrospectively assess the factors related to cervical trauma, according to the type of fracture based on the AO classification, taking into account etiological and epidemiological aspects of the event. METHODS: Records of patients with cervical fractures were retrospectively reviewed, from 2004 to 2009. The sub-axial fractures (C3-C7 were studied because they fit into only one classification (AO. Frontal and lateral x-rays were used as well as CTs to divide the fractures into A (compression, B (distraction and C (rotation, in accordance with the presented pattern. The following parameters were assessed: gender, age, AO classification, trauma mechanism, presence of neurological deficit, and conservative or surgical treatment. RESULTS: The study included 264 records from the spine, where 216 patients were male and 48

  2. CT-based virtual tracheobronchoscopy in children - comparison with axial CT and multiplanar reconstruction: preliminary results

    International Nuclear Information System (INIS)

    Sorantin, Erich; Lindbichler, Franz; Eber, Ernst; Schimpl, Guenther

    2002-01-01

    Background: 3D post-processing of spiral-CT (S-CT) data using perspective projection allows the generation of virtual views similar to endoscopy. Objective: To evaluate whether simultaneous reading of axial S-CT, multiplanar reconstruction (MPR) and virtual tracheobronchoscopy (VTB) is more precise and accurate than reading of axial S-CT and MPR alone in paediatric patients. Materials and methods: S-CT studies of 15 symptomatic and 4 normal patients were investigated. Two radiologists independently read two sets of images for airway abnormalities: first axial CT and MPR, followed by axial CT, MPR and VTB. A final decision was later made by consensus. All results were compared to fibre-optic bronchoscopy (FTB). Interobserver agreement was used as an indicator of precision for the display technique used. Results: At reading of axial S-CT and MPR an interobserver agreement of 89.5% (κ=0.776, P<0.00103) was found. Based on the consensus decision, a diagnostic accuracy of 89.5% at a sensitivity 86.6% and specificity of 100% (κ=0.776, 95% CI 0.491-1.062, P<0.00103) was achieved. At reporting on axial S-CT, MPR and VTB, all cases were classified correctly by both readers, indicating 100% accuracy, interobserver agreement, sensitivity and specificity (κ=1.00, 95% CI 1.0-1.0, P<0.000258). Conclusions: The simultaneous display of axial S-CT, MPR and VTB raises the precision, accuracy and sensitivity of radiological reports. (orig.)

  3. The internal vertebral venous plexus prevents compression of the dural sac during atlanto-axial rotation

    Energy Technology Data Exchange (ETDEWEB)

    Reesink, E.M.; Lataster, L.M.A.; Mameren, H. van [Dept. of Anatomy/Embryology, Maastricht Univ. (Netherlands); Wilmink, J.T. [Dept. of Radiology, University Hospital Maastricht (Netherlands); Kingma, H. [Dept. of ENT, University Hospital Maastricht (Netherlands)

    2001-10-01

    Deformation of the extradural space and the possibility of impression upon the dural sac during atlanto-axial rotation are investigated. Atlanto-axial rotation leads to a reduction in the cross-sectional area of the bony spinal canal of approximately 40 %. Atlanto-axial rotation was recorded by endocanalar views from a video camera fixed inside the skull of six unembalmed cadavers. Axial thin-section T1-weighted MRI slice sets were acquired from three volunteers (mid-position and maximal left and right rotation of the head and cervical spine). The axial cross-sectional areas of the bony spinal canal, dural sac and spinal cord were measured. In two other persons post-gadolinium contrast-enhanced T1-weighted MRI volume scans with fat-suppression prepulse were acquired (mid-position and rotation) to determine venous contents of the extradural space. The 50:50 ratio between left and right extradural halves in mid-position changed to an ipsilateral:contralateral ratio of 20:80 in maximum rotation at the level just above the lateral C1-C2 joints. Directly below these joints the opposite occurred. The post-contrast studies showed an enhancing internal vertebral venous plexus (IVVP), which almost completely occupied the extradural space at the atlanto-axial level. This could not be shown in the cadaver experiments, because of absence of blood and cerebrospinal fluid (CSF) pressure. During atlanto-axial rotation blood displacement in the IVVP allows major deformations of the extradural space. This prevents dural sac impression. (orig.)

  4. Transverse Vibration of Axially Moving Functionally Graded Materials Based on Timoshenko Beam Theory

    Directory of Open Access Journals (Sweden)

    Suihan Sui

    2015-01-01

    Full Text Available The transverse free vibration of an axially moving beam made of functionally graded materials (FGM is investigated using a Timoshenko beam theory. Natural frequencies, vibration modes, and critical speeds of such axially moving systems are determined and discussed in detail. The material properties are assumed to vary continuously through the thickness of the beam according to a power law distribution. Hamilton’s principle is employed to derive the governing equation and a complex mode approach is utilized to obtain the transverse dynamical behaviors including the vibration modes and natural frequencies. Effects of the axially moving speed and the power-law exponent on the dynamic responses are examined. Some numerical examples are presented to reveal the differences of natural frequencies for Timoshenko beam model and Euler beam model. Moreover, the critical speed is determined numerically to indicate its variation with respect to the power-law exponent, axial initial stress, and length to thickness ratio.

  5. A free vibration of beams carrying a concentrated mass under distributed axial forces

    International Nuclear Information System (INIS)

    Nagai, Ken-ichi; Nagaya, Kosuke; Takeda, Sadahiko; Arai, Noriyuki.

    1988-01-01

    The free bending vibrations of beams with a concentrated mass subjected to axial forces caused by axial acceleration are analyzed by the Galerkin method, introducing the mode shape functions which are the sum of the products of the finite power series and the trigonometrical function. This analytical method makes it easy to construct the equations of motion in each boundary condition only by exchanging the coefficients of the finite power series. Numerical calculations are carried out under four sets of boundary conditions combined with simply supported and clamped edges. The natural frequencies and the corresponding modes of vibration are determined under both various locations of the concentrated mass and axial forces. it is found that the transverse inertia force and the axial force, due to the concentrated mass, have significant effects on the change of the natural frequencies for beams. Furthermore the distinction of boundary conditions gives predominant influence to the variation of natural frequencies. (author)

  6. The relationship between the types of axial elongation and the prevalence of lattice degeneration of the retina.

    Science.gov (United States)

    Yura, T

    1998-02-01

    To assess the relationship between the prevalence of lattice degeneration and the types of axial elongation. Nine hundred seventy eyes of 542 highly myopic patients with axial length of 26.00-31.99 mm were evaluated by using A-scan axial length measurements and fundus examinations. Then the prevalence of lattice degeneration was compared between eyes with posterior staphyloma and those without posterior staphyloma. At each axial length, lattice degeneration was more frequent in eyes without posterior staphyloma (the entire eye elongates) than those with posterior staphyloma (only the posterior pole elongates). The difference was statistically significant (plattice degeneration is influenced by the types of axial elongation in high myopic eyes.

  7. Axial mercury segregation in direct current operated low-pressure argon-mercury gas discharges: Part I. Experimental

    International Nuclear Information System (INIS)

    Gielen, John W A M; Groot, Simon de; Mullen, Joost J A M van der

    2004-01-01

    Due to cataphoresis, axial segregation of mercury will occur when the gas discharge of a fluorescent lamp is operated by means of a direct current. A consequence of this is a non-uniform axial luminance distribution along the lamp. To determine the degree of axial mercury segregation experimentally, axial luminance distributions have been measured which are converted into axial mercury vapour pressure distributions by an appropriate calibration method. The mercury segregation has been investigated for variations in lamp tube radius (3.6-4.8 mm), argon buffer gas pressure (200-600 Pa) and lamp current (100-250 mA) at mercury vapour pressures set at the anode in the range from 0.2 to 9.0 Pa. From the experiments it has been concluded that the mercury vapour pressure gradient at any axial position for a certain lamp tube diameter, argon pressure and lamp current depends on the local mercury vapour pressure. This observation is in contrast to assumptions made in earlier modelling publications in which one mercury vapour pressure gradient is used for all axial positions. By applying a full factorial design, an empirical relation of the mercury segregation is found for any set of parameters inside the investigated parameter ranges

  8. Accessory caudal axial and pelvic ribs

    International Nuclear Information System (INIS)

    Bohutova, J.; Kolar, J.; Vitovec, J.; Vyhnanek, L.

    1980-01-01

    Accessory caudal ribs are reported as an extremely curious anomaly in five patients. Once the fracture of this rib was a source of pains after injury. The different shapes of the ribs are documented in this clinical survey which is the most extensive in the present literature. Anomalous ribs arise due to inappropriate segmentation during the embryonal development of the axial skeleton. (orig.) [de

  9. A study of friction and axial effects in pellet-clad mechanical interaction

    International Nuclear Information System (INIS)

    Harriague, Santiago; Mayer, J.E.

    1982-01-01

    An analysis is made of the effect of friction and axial forces along the fuel rod in the pellet-cladding mechanical interaction in a commercial reactor under a power-up ramp. The effect of different pellet and rod shapes on their behaviour was also determined. A linear thermoelastic computer program was used in order to obtain the stiffness matrix of a compound structure from the stiffness of its components. Pellet-cladding displacements, localized deformations of the cladding in the interfaces between pellets, as well as pellet and cladding axial deformations were determined for different power axial profiles as well as for pellets with and without dishing and with height/diameter ratios of 1.7, 1 and 0.5. (M.E.L.) [es

  10. Holographic estimate of the meson cloud contribution to nucleon axial form factor

    Science.gov (United States)

    Ramalho, G.

    2018-04-01

    We use light-front holography to estimate the valence quark and the meson cloud contributions to the nucleon axial form factor. The free couplings of the holographic model are determined by the empirical data and by the information extracted from lattice QCD. The holographic model provides a good description of the empirical data when we consider a meson cloud mixture of about 30% in the physical nucleon state. The estimate of the valence quark contribution to the nucleon axial form factor compares well with the lattice QCD data for small pion masses. Our estimate of the meson cloud contribution to the nucleon axial form factor has a slower falloff with the square momentum transfer compared to typical estimates from quark models with meson cloud dressing.

  11. The Relation Between Plate Spreading Rate, Crustal Thickness and Axial Relief at Mid-Ocean Ridges

    Science.gov (United States)

    Liu, Z.; Buck, W. R.

    2017-12-01

    Variations in axial valley relief and in faulting at plate spreading centers are clearly related to magma supply and axial lithospheric structure. Previous models that consider the interaction of magmatic dikes with lithospheric stretching do not successfully reproduce both of these trends. We present the first model that reproduces these trends by making simple assumptions about the partitioning of magma between dikes, gabbros and extrusives. A key concept is that dikes open not only in the brittle axial lithosphere but also into the underlying ductile crust, where they cool to form gabbro. The amount of gabbro so intruded depends on magma pressure that is related to axial relief. The deeper the valley the less magma goes into gabbros and the more magma is available for dikes to accommodate plate separation. We define the fraction of plate separation rate accommodated by dikes as M. If Mreasonable. Finally, we describe themo-mechanical models that allow us to relate plate spreading rate and crustal thickness and to axial valley depth.

  12. Dispersion relation and growth rate in a Cherenkov free electron laser: Finite axial magnetic field

    International Nuclear Information System (INIS)

    Kheiri, Golshad; Esmaeilzadeh, Mahdi

    2013-01-01

    A theoretical analysis is presented for dispersion relation and growth rate in a Cherenkov free electron laser with finite axial magnetic field. It is shown that the growth rate and the resonance frequency of Cherenkov free electron laser increase with increasing axial magnetic field for low axial magnetic fields, while for high axial magnetic fields, they go to a saturation value. The growth rate and resonance frequency saturation values are exactly the same as those for infinite axial magnetic field approximation. The effects of electron beam self-fields on growth rate are investigated, and it is shown that the growth rate decreases in the presence of self-fields. It is found that there is an optimum value for electron beam density and Lorentz relativistic factor at which the maximum growth rate can take place. Also, the effects of velocity spread of electron beam are studied and it is found that the growth rate decreases due to the electron velocity spread

  13. Growth-induced axial buckling of a slender elastic filament embedded in an isotropic elastic matrix

    KAUST Repository

    O'Keeffe, Stephen G.

    2013-11-01

    We investigate the problem of an axially loaded, isotropic, slender cylinder embedded in a soft, isotropic, outer elastic matrix. The cylinder undergoes uniform axial growth, whilst both the cylinder and the surrounding elastic matrix are confined between two rigid plates, so that this growth results in axial compression of the cylinder. We use two different modelling approaches to estimate the critical axial growth (that is, the amount of axial growth the cylinder is able to sustain before it buckles) and buckling wavelength of the cylinder. The first approach treats the filament and surrounding matrix as a single 3-dimensional elastic body undergoing large deformations, whilst the second approach treats the filament as a planar, elastic rod embedded in an infinite elastic foundation. By comparing the results of these two approaches, we obtain an estimate of the foundation modulus parameter, which characterises the strength of the foundation, in terms of the geometric and material properties of the system. © 2013 Elsevier Ltd. All rights reserved.

  14. HTS axial flux induction motor with analytic and FEA modeling

    Energy Technology Data Exchange (ETDEWEB)

    Li, S., E-mail: alexlee.zn@gmail.com; Fan, Y.; Fang, J.; Qin, W.; Lv, G.; Li, J.H.

    2013-11-15

    Highlights: •A high temperature superconductor axial flux induction motor and a novel maglev scheme are presented. •Analytic method and finite element method have been adopted to model the motor and to calculate the force. •Magnetic field distribution in HTS coil is calculated by analytic method. •An effective method to improve the critical current of HTS coil is presented. •AC losses of HTS coils in the HTS axial flux induction motor are estimated and tested. -- Abstract: This paper presents a high-temperature superconductor (HTS) axial-flux induction motor, which can output levitation force and torque simultaneously. In order to analyze the character of the force, analytic method and finite element method are adopted to model the motor. To make sure the HTS can carry sufficiently large current and work well, the magnetic field distribution in HTS coil is calculated. An effective method to improve the critical current of HTS coil is presented. Then, AC losses in HTS windings in the motor are estimated and tested.

  15. HTS axial flux induction motor with analytic and FEA modeling

    International Nuclear Information System (INIS)

    Li, S.; Fan, Y.; Fang, J.; Qin, W.; Lv, G.; Li, J.H.

    2013-01-01

    Highlights: •A high temperature superconductor axial flux induction motor and a novel maglev scheme are presented. •Analytic method and finite element method have been adopted to model the motor and to calculate the force. •Magnetic field distribution in HTS coil is calculated by analytic method. •An effective method to improve the critical current of HTS coil is presented. •AC losses of HTS coils in the HTS axial flux induction motor are estimated and tested. -- Abstract: This paper presents a high-temperature superconductor (HTS) axial-flux induction motor, which can output levitation force and torque simultaneously. In order to analyze the character of the force, analytic method and finite element method are adopted to model the motor. To make sure the HTS can carry sufficiently large current and work well, the magnetic field distribution in HTS coil is calculated. An effective method to improve the critical current of HTS coil is presented. Then, AC losses in HTS windings in the motor are estimated and tested

  16. A benchmark study of procedures for analysis of axial crushing of bulbous bows

    DEFF Research Database (Denmark)

    Yamada, Yasuhira; Pedersen, Preben Terndrup

    2008-01-01

    Simplified methods to estimate mean axial crushing forces of plated structures are reviewed and applied to a series of experimental results for axial crushing of large-scale bulbous bow models. Methods based on intersection unit elements such as L-, T- and X-type elements as well as methods based...

  17. Classical theory of the Kumakhov radiation in axial channeling

    International Nuclear Information System (INIS)

    Khokonov, M.K.; Komarov, F.F.; Telegin, V.I.

    1984-01-01

    The paper considers radiation of ultrarelativistic electrons in axial channeling initially predicted by Kumakhov. The consideration is based on the results of solution of the Fokker-Planck equation. The spectral-angular characteristics of the Kumakhov radiation in thick single crystals are calculated. It is shown that in heavy single crystals the energy losses on radiation can amount to a considerable portion of the initial beam energy. The possibility of a sharp increase of radiation due to a decrease of crystal temperature is discussed. It is shown that radiation intensity in axial channeling is weakly dependent on the initial angle of the electron entrance into the channel if this angle changes within the limits of a critical one. (author)

  18. Impact of axial velocity and transmembrane pressure (TMP) on ARP filter performance

    Energy Technology Data Exchange (ETDEWEB)

    Poirier, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Burket, P. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-02-29

    The Savannah River Site (SRS) is currently treating radioactive liquid waste with the Actinide Removal Process (ARP) and the Modular Caustic Side Solvent Extraction Unit (MCU). Recently, the low filter flux through the ARP of approximately 5 gallons per minute has limited the rate at which radioactive liquid waste can be treated. Salt Batch 6 had a lower processing rate and required frequent filter cleaning. Savannah River Remediation (SRR) has a desire to understand the causes of the low filter flux and to increase ARP/MCU throughput. One potential method for increasing filter flux is to adjust the axial velocity and transmembrane pressure (TMP). SRR requested SRNL to conduct bench-scale filter tests to evaluate the effects of axial velocity and transmembrane pressure on crossflow filter flux. The objective of the testing was to determine whether increasing the axial velocity at the ARP could produce a significant increase in filter flux. The authors conducted the tests by preparing slurries containing 6.6 M sodium Salt Batch 6 supernate and 2.5 g MST/L, processing the slurry through a bench-scale crossflow filter unit at varying axial velocity and TMP, and measuring filter flux as a function of time.

  19. Notchless is required for axial skeleton formation in mice.

    Directory of Open Access Journals (Sweden)

    Sarah Beck-Cormier

    Full Text Available Maintenance of cell survival is essential for proper embryonic development. In the mouse, Notchless homolog 1 (Drosophila (Nle1 is instrumental for survival of cells of the inner cell mass upon implantation. Here, we analyze the function of Nle1 after implantation using the Meox2(tm1(creSor mouse that expresses the Cre recombinase specifically in the epiblast at E5.5. First, we find that NLE1 function is required in epiblast cells, as Nle1-deficient cells are rapidly eliminated. In this report, we also show that the Meox2(Cre transgene is active in specific tissues during organogenesis. In particular, we detect high Cre expression in the vertebral column, ribs, limbs and tailbud. We took advantage of this dynamic expression profile to analyze the effects of inducing mosaic deletion of Nle1 in the embryo. We show that Nle1 deletion in this context, results in severe developmental anomalies leading to lethality at birth. Mutant embryos display multiple developmental defects in particular during axial skeletal formation. We also provide evidence that axial defects are due to an increase in apoptotic cell death in the somite at E9.5. These data demonstrate an essential role for Nle1 during organogenesis and in particular during axial development.

  20. Notchless is required for axial skeleton formation in mice.

    Science.gov (United States)

    Beck-Cormier, Sarah; Escande, Marie; Souilhol, Céline; Vandormael-Pournin, Sandrine; Sourice, Sophie; Pilet, Paul; Babinet, Charles; Cohen-Tannoudji, Michel

    2014-01-01

    Maintenance of cell survival is essential for proper embryonic development. In the mouse, Notchless homolog 1 (Drosophila) (Nle1) is instrumental for survival of cells of the inner cell mass upon implantation. Here, we analyze the function of Nle1 after implantation using the Meox2(tm1(cre)Sor) mouse that expresses the Cre recombinase specifically in the epiblast at E5.5. First, we find that NLE1 function is required in epiblast cells, as Nle1-deficient cells are rapidly eliminated. In this report, we also show that the Meox2(Cre) transgene is active in specific tissues during organogenesis. In particular, we detect high Cre expression in the vertebral column, ribs, limbs and tailbud. We took advantage of this dynamic expression profile to analyze the effects of inducing mosaic deletion of Nle1 in the embryo. We show that Nle1 deletion in this context, results in severe developmental anomalies leading to lethality at birth. Mutant embryos display multiple developmental defects in particular during axial skeletal formation. We also provide evidence that axial defects are due to an increase in apoptotic cell death in the somite at E9.5. These data demonstrate an essential role for Nle1 during organogenesis and in particular during axial development.

  1. Axial tomography

    International Nuclear Information System (INIS)

    Brueckner, K.A.; Lewis, J.H.

    1979-01-01

    The invention relates to axial tomography, sometimes referred to as cross-sectional x-ray. The apparatus described may utilize the conventional x-ray or ultrasonic source and detector and scanning mechanism for producing the plurality of sets of radiation detector output signals. It has the means for storing the detector output signals in analog form with the signals of one set overlying the signals of another set so that signals resulting from radiation through a zone of the object being examined are summed at a corresponding zone in the storage device, typically an electronic storage tube. The summed signals are read from the storage device with a radially inversely proportional reader producing a second signal for storage, again typically in an electronic storage tube. These signals stored in the second storage device are read with Laplacian relation, with the resultant sigal being a video signal that may be connected to a TV monitor for display of the sectional image. In alternative embodiments, optical film systems and electrostatic systems are utilized. (JTA)

  2. Effect of intervertebral disk degeneration on spinal stenosis during magnetic resonance imaging with axial loading

    International Nuclear Information System (INIS)

    Ahn, Tae-Joon; Lee, Sang-Ho; Choi, Gun; Ahn, Yong; Liu, Wei-Chiang; Kim, Ho-Jin; Lee, Ho-Yeon

    2009-01-01

    Magnetic resonance (MR) imaging with axial loading can simulate the physiological standing state and disclose spinal stenosis undetected or underestimated in the conventional position. Intervertebral disk degeneration may be an important factor in spinal stenosis. This study investigated whether intervertebral disk degeneration increases spinal stenosis during axial loading. MR imaging with and without axial loading was obtained in 51 patients with neurogenic intermittent claudication and/or sciatica and reviewed retrospectively. The grade of disk degeneration was rated in four disk spaces from L2-3 to L5-S1. The dural sac cross-sectional area (DCSA) was measured on MR images taken in both conventional and axial loading positions, and the change in the DCSA was calculated. The effect of disk degeneration on the DCSA was statistically analyzed. Significant decreases in the DCSA occurred with grade 4 disk degeneration (mean±standard deviation, 20.1±14.1 mm 2 ), followed by grade 3 (18.3±15.1 mm 2 ) and grade 2 (8.9±13.1 mm 2 ). DCSA decreased considerably with increased severity of disk degeneration with axial loading, except for grade 5 disk degeneration. More accurate diagnosis of stenosis can be achieved using MR imaging with axial loading, especially if grade 2 to 4 disk degeneration is present. (author)

  3. Magnetic resonance imaging of the lumbar spine with axial loading: A review of 120 cases

    International Nuclear Information System (INIS)

    Kinder, Andre; Palma Filho, Fernando; Ribeiro, Elisio; Domingues, Romeu C.; Domingues, Roberto C.; Marchiori, Edson; Gasparetto, Emerson

    2012-01-01

    Purpose: To evaluate the imaging findings of patients with clinical symptoms of lower back pain who underwent magnetic resonance imaging (MRI) of the lumbar spine with axial loading. Materials and methods: We examined 120 patients by MRI, before and after axial loading, using a compression device that applied 50% of their body weight for a load time of 5 min. The dural sac cross area (DSCA) was examined by two experienced radiologists before and after axial load, and their findings were compared. Degenerative abnormalities within and adjacent to the spinal canal were also analyzed. Results: A reduction in DSCA greater than 15 mm 2 after axial load was defined as significant, and was found in 81 patients (67.5%) and 138 disc spaces (38.3%). Reduction was most frequent at L4-L5 (n = 55). For other disorders, a 9% increase in cases of bulging disc was seen during axial loading, and seven disc spaces showed protrusion/extrusion only after load. Facet joint synovial cysts, foraminal stenosis, and hypertrophy of the flavum ligaments showed almost no differences, pre- and post-load. Conclusion: For adequate evaluation of lumbar symptoms, examination should be performed with axial loading, especially in cases of suspected spinal stenosis.

  4. An Axial Sliding Test for machine elements surfaces

    DEFF Research Database (Denmark)

    Godi, Alessandro; Grønbæk, J.; Mohaghegh, Kamran

    2012-01-01

    are necessary: a press to provide the normal pressure and a tensile machine to perform the axial movements. The test is calibrated so that the correspondence between the normal pressure and the container advancement is found. Finally, preliminary tests are carried out involving a multifunctional and a fine......Throughout the years, it has become more and more important to find new methods for reducing friction and wear occurrence in machine elements. A possible solution is found in texturing the surfaces under tribological contact, hence the development and spread of plateau-honed surface for cylinder...... liners. To prove the efficacy of a particular textured surface, it is paramount to perform experimental tests under controlled laboratory conditions. In this paper a new test rig simulating pure sliding conditions is presented, dubbed Axial Sliding Test. It presents four major components: a rod, a sleeve...

  5. Axial weak currents in the Wess-Zumino term

    International Nuclear Information System (INIS)

    Fujikawa, Kazuo

    1986-01-01

    In a simplified model lagrangian of 3 quarks with an SU(2)sub(L) gauging of chiral SU(3)sub(L)xSU(3)sub(R) to introduce W-boson, we analyse certain complications associated with the low-energy theorem including axial weak fields. We first show that the low-energy amplitude is independent of the form of the quark-level anomalous identity, whether in the covariant form or the consistent form. However, the interplay of the short-distance dynamics (anomalous identity) and the long-distance dynamics (low-energy theorem) becomes involved in the presence of axial fields. We then discuss what kinds of conditions single out the gauged Wess-Zumino term as a low-energy effective action. The connection of the low-energy theorem with the 't Hooft anomaly matching condition is also discussed. (orig.)

  6. Ependimoma celular parcialmente resecado complicado con meningoependimocoroiditis bacteriana por Pseudomonas aeruginosa e infección sistémica por citomegalovirus

    Directory of Open Access Journals (Sweden)

    Francisco Javier Otero-Mendoza

    2017-06-01

    Full Text Available Niño de 1 año 10 meses de edad, originario de Irapuato, Guanajuato, sin antecedentes de importancia para el padecimiento actual. Inició dos meses previos a su ingreso con crisis convulsivas tónico-clónicas generalizadas de 15 segundos de duración durante el sueño. Se realizó electroencefalograma que reportó actividad epileptiforme, por lo que se dio tratamiento con ácido valproico. Una semana previa al ingreso se agregó ataxia troncal impidiendo la marcha, por lo que se realizó una tomografía axial computarizada de cráneo en la que se observó un tumor en fosa posterior con densidad heterogénea y áreas de necrosis central que obliteraba el cuarto ventrículo, ocasionando efecto de masa y desplazamiento ventral del tallo cerebral. Por tal motivo, fue referido a nuestra institución.

  7. Study of different aerodynamics modifications for small axial flow fan

    OpenAIRE

    Bin Abdul Jalil, Anas

    2017-01-01

    En este proyecto, se investigaron los efectos de los álabes en el comportamiento aerodinámico de pequeños ventiladores axiales para disminuir la turbulencia del flujo en su superficie y generalmente para mejorar el rendimiento aerodinámico. Se estudiaron mediante simulación dos modificaciones en la superficie de los alabes de un pequeño ventilador axial (modelo 1, prototipo): la situación de un “winglet” en el extremo del álabe (modelo 2) y el diseño denominado de “aleta de tiburón” (modelo 3...

  8. Post-buckling capacity of bi-axially loaded rectangular steel plates

    DEFF Research Database (Denmark)

    Jönsson, Jeppe; Bondum, T. H.

    2012-01-01

    slenderness and edge displacement ratio are included in the investigations presented. Capacity interaction curves are established in the bi-axial stress domain. It turns out that for certain stress ratios the imperfections dominating the ultimate capacity are not affine to the lowest classical buckling mode...... for biaxial stress. It is of great interest that short wave imperfections of a lower magnitude compared to conventionally used imperfections are seen to lower the capacity of the bi-axially loaded plates. The topic is of major concern in the flange plates of long span bridges with multi box girder...

  9. Long axial imaging range using conventional swept source lasers in optical coherence tomography via re-circulation loops

    Science.gov (United States)

    Bradu, Adrian; Jackson, David A.; Podoleanu, Adrian

    2018-03-01

    Typically, swept source optical coherence tomography (SS-OCT) imaging instruments are capable of a longer axial range than their camera based (CB) counterpart. However, there are still various applications that would take advantage for an extended axial range. In this paper, we propose an interferometer configuration that can be used to extend the axial range of the OCT instruments equipped with conventional swept-source lasers up to a few cm. In this configuration, the two arms of the interferometer are equipped with adjustable optical path length rings. The use of semiconductor optical amplifiers in the two rings allows for compensating optical losses hence, multiple paths depth reflectivity profiles (Ascans) can be combined axially. In this way, extremely long overall axial ranges are possible. The use of the recirculation loops produces an effect equivalent to that of extending the coherence length of the swept source laser. Using this approach, the achievable axial imaging range in SS-OCT can reach values well beyond the limit imposed by the coherence length of the laser, to exceed in principle many centimeters. In the present work, we demonstrate axial ranges exceeding 4 cm using a commercial swept source laser and reaching 6 cm using an "in-house" swept source laser. When used in a conventional set-up alone, both these lasers can provide less than a few mm axial range.

  10. NUMERICAL PREDICTION OF COMPOSITE BEAM SUBJECTED TO COMBINED NEGATIVE BENDING AND AXIAL TENSION

    Directory of Open Access Journals (Sweden)

    MAHESAN BAVAN

    2013-08-01

    Full Text Available The present study has investigated the finite element method (FEM techniques of composite beam subjected to combined axial tension and negative bending. The negative bending regions of composite beams are influenced by worsen failures due to various levels of axial tensile loads on steel section especially in the regions near internal supports. Three dimensional solid FEM model was developed to accurately predict the unfavourable phenomenon of cracking of concrete and compression of steel in the negative bending regions of composite beam due to axial tensile loads. The prediction of quasi-static solution was extensively analysed with various deformation speeds and energy stabilities. The FEM model was then validated with existing experimental data. Reasonable agreements were observed between the results of FEM model and experimental analysis in the combination of vertical-axial forces and failure modes on ultimate limit state behaviour. The local failure modes known as shear studs failure, excess yielding on steel beam and crushing on concrete were completely verified by extensive similarity between the numerical and experimental results. Finally, a proper way of modelling techniques for large FEM models by considering uncertainties of material behaviour due to biaxial loadings and complex contact interactions is discussed. Further, the model is suggested for the limit state prediction of composite beam with calibrating necessary degree of the combined axial loads.

  11. The Distal Humerus Axial View: Assessment of Displacement in Medial Epicondyle Fractures.

    Science.gov (United States)

    Souder, Christopher D; Farnsworth, Christine L; McNeil, Natalie P; Bomar, James D; Edmonds, Eric W

    2015-01-01

    The assessment and treatment of childhood medial epicondyle humerus fractures continues to be associated with significant debate. Several studies demonstrate that standard radiographic views are unable to accurately portray the true displacement. Without reliable ways to assess the amount of displacement, how can we debate treatment and outcomes? This study introduces a novel imaging technique for the evaluation of medial epicondyle fractures. An osteotomy of a cadaveric humerus was performed to simulate a medial epicondyle fracture. Plain radiographs were obtained with the fracture fragment displaced anteriorly in 2-mm increments between 0 and 18 mm. Anteroposterior (AP), internal oblique (IR), lateral (LAT), and distal humerus axial (AXIAL) views were performed. Axial images were obtained by positioning the central ray above the shoulder at 15 to 20 degrees from the long axis of the humerus, centered on the distal humerus. Displacement (mm) was measured by 7 orthopaedic surgeons on digital radiographs. At 10 mm displacement, AP views underestimated displacement by 5.5±0.6 mm and IR views underestimated by 3.8±2.1 mm. On LAT views, readers were not able to visualize fragments with displacement. Displacement ≥10 mm from LAT views was overestimated by 1 reader by up to 4.6 mm and underestimated by others by up to 18.0 mm. AXIAL images more closely estimated the true amount of displacement, with a mean 1.5±1.1 mm error in measurement for displacement and a mean 0.8±0.7 mm error for displacements of ≥10 mm. AXIAL measurements correlated strongly with the actual displacement (r=0.998, Pdisplacement of medial epicondyle humerus fractures. The newly described AXIAL projection more accurately and reliably demonstrated the true displacement while reducing the need for advanced imaging such as computed tomography. This simple view can be easily obtained at a clinic visit, enhancing the surgeon's ability to determine the true displacement.

  12. Profiling Cognitive Deficits in Intra-Axial and Extra-Axial Tumors Using Addenbrooke's Cognitive Examination as a Screening Tool: An Indian Experience.

    Science.gov (United States)

    Cherkil, Sandhya; Panikar, Dilip; Soman, Deepak Kuttikkattu

    2017-01-01

    Tumors of the brain, whether intra- or extra-axial, results in cognitive deficits. The aim of the present study was to profile cognitive deficits using Addenbrooke's Cognitive Examination-Malayalam (ACE-M) as a screen and to determine the sensitivity and specificity of the same. Seventy-four drug naïve patients diagnosed to have brain tumors were assessed for cognitive functioning using ACE-M before surgery. Patients with high-grade intra-axial tumors showed a significant association on the cognitive domains of registration (0.04), recall (0.01), and visuospatial functioning (0.02). Gender showed an association between registration (0.02) and verbal fluency (0.02) with females performing better while education was significantly associated with retrograde or remote memory (0.00) with college-educated sample performing better. Significance was assumed at P cognitive decline on the cognitive domains of attention (0.02), recall (0.05), naming (0.02), and language functions (0.01). College educated group performed better on registration (0.01), recall (0.09), naming (0.00), and visuospatial functioning (0.00). The area under the receiver operating characteristic curve was estimated as 0.75, which indicates fairly good discriminative ability with a cut off of 71/100; sensitivity at 77.3 and specificity fixed at 67. ACE-M is capable of bringing out cognitive deficits along with a number of cognitive domains in patients with intra- and extra-axial tumors in the capacity of a screen, with fairly good levels of sensitivity and specificity.

  13. Effects of casing treatment on a small, transonic axial-flow compressor

    Science.gov (United States)

    Holman, F. F.; Kidwell, J. R.

    1975-01-01

    Improved axial compressor surge margin through effective rotor casing treatment has been identified from test results on large axial compressors. A modified scale of a large compressor was built and tested to determine if similar improvements in surge margin could be duplicated in small-size turbomachinery. In addition, the effects of rotor radial running clearance, both with and without casing treatment, were investigated and are discussed. Test results of the scale configuration are presented and compared to the parent compressor.

  14. Internal and external axial corner flows

    Science.gov (United States)

    Kutler, P.; Shankar, V.; Anderson, D. A.; Sorenson, R. L.

    1975-01-01

    The inviscid, internal, and external axial corner flows generated by two intersecting wedges traveling supersonically are obtained by use of a second-order shock-capturing, finite-difference approach. The governing equations are solved iteratively in conical coordinates to yield the complicated wave structure of the internal corner and the simple peripheral shock of the external corner. The numerical results for the internal flows compare favorably with existing experimental data.

  15. PWR AXIAL BURNUP PROFILE ANALYSIS

    International Nuclear Information System (INIS)

    J.M. Acaglione

    2003-01-01

    The purpose of this activity is to develop a representative ''limiting'' axial burnup profile for pressurized water reactors (PWRs), which would encompass the isotopic axial variations caused by different assembly irradiation histories, and produce conservative isotopics with respect to criticality. The effect that the low burnup regions near the ends of spent fuel have on system reactivity is termed the ''end-effect''. This calculation will quantify the end-effects associated with Pressurized Water Reactor (PWR) fuel assemblies emplaced in a hypothetical 21 PWR waste package. The scope of this calculation covers an initial enrichment range of 3.0 through 5.0 wt% U-235 and a burnup range of 10 through 50 GWd/MTU. This activity supports the validation of the process for ensuring conservative generation of spent fuel isotopics with respect to criticality safety applications, and the use of burnup credit for commercial spent nuclear fuel. The intended use of these results will be in the development of PWR waste package loading curves, and applications involving burnup credit. Limitations of this evaluation are that the limiting profiles are only confirmed for use with the B andW 15 x 15 fuel assembly design. However, this assembly design is considered bounding of all other typical commercial PWR fuel assembly designs. This calculation is subject to the Quality Assurance Requirements and Description (QARD) because this activity supports investigations of items or barriers on the Q-list (YMP 2001)

  16. Whole-body magnetic resonance imaging in axial spondyloarthritis

    DEFF Research Database (Denmark)

    Krabbe, Simon; Østergaard, Mikkel; Eshed, Iris

    2018-01-01

    Objective. To investigate whether adalimumab (ADA) reduces whole-body (WB-) magnetic resonance imaging (MRI) indices for inflammation in the entheses, peripheral joints, sacroiliac joints, spine, and the entire body in patients with axial spondyloarthritis (axSpA). Methods. An investigator-initia...

  17. TRANPZ - A computer code for the simulation of reactors with axial dependence

    International Nuclear Information System (INIS)

    Sampaio, L.C.M.

    1980-12-01

    A computer code was developed to simulate a PWR reactor in steady state and during transients. The solution of one speed diffusion equation in the axial direction is obtained numerically dividing the core in various axial segments and the axial power distribution is obtained there from. A method was developed to determine the transient solution. The external reactivity effects are caused by the motion of the control rods, starting from the steady condition with the control rods in any position. The heat conduction equation in the fuel is numerically solved in the radial direction. Various tests were performed in steady state and transient conditions and the validity of the present model was verified. Results were compared in steady state condition with the code CITATION and a reasonable agreement was found. (E.G.) [pt

  18. Electron angular distribution axial channeling

    International Nuclear Information System (INIS)

    Khokonov, A.Kh.; Khokonov, M.Kh.

    1989-01-01

    Angular distributions of ultra-relativistic electrons are calculated in the assumption about presence of statistical equilibrium. Analysis is based on numerical solution of Fokker-Planck type kinetic equation. It is shown that in contrast to case of amorphous medium, the multiple scattering at axial channeling of negative particles results in self-focusing of the initial beam particles and due to it number of electrons moving at an angles to the chain, which are smaller, than critical angle of channeling, may increase by several times as compared to the initial one

  19. Axial tomography in live cell laser microscopy

    Science.gov (United States)

    Richter, Verena; Bruns, Sarah; Bruns, Thomas; Weber, Petra; Wagner, Michael; Cremer, Christoph; Schneckenburger, Herbert

    2017-09-01

    Single cell microscopy in a three-dimensional (3-D) environment is reported. Cells are grown in an agarose culture gel, located within microcapillaries and observed from different sides after adaptation of an innovative device for sample rotation. Thus, z-stacks can be recorded by confocal microscopy in different directions and used for illustration in 3-D. This gives additional information, since cells or organelles that appear superimposed in one direction, may be well resolved in another one. The method is tested and validated with single cells expressing a membrane or a mitochondrially associated green fluorescent protein, or cells accumulating fluorescent quantum dots. In addition, axial tomography supports measurements of cellular uptake and distribution of the anticancer drug doxorubicin in the nucleus (2 to 6 h after incubation) or the cytoplasm (24 h). This paper discusses that upon cell rotation an enhanced optical resolution in lateral direction compared to axial direction can be utilized to obtain an improved effective 3-D resolution, which represents an important step toward super-resolution microscopy of living cells.

  20. The contribution of axial-vector mesons to hyperfine structure of muonic hydrogen

    OpenAIRE

    Dorokhov, A. E.; Kochelev, N. I.; Martynenko, A. P.; Martynenko, F. A.; Radzhabov, A. E.

    2017-01-01

    The contribution from the axial-vector meson exchange to the potential of the muon–proton interaction in muonic hydrogen induced by anomalous axial-vector meson coupling to two photon state is calculated. It is shown that such contribution to the hyperfine splitting in muonic hydrogen is large and important for a comparison with precise experimental data. In the light of our result, the proton radius “puzzle” is discussed.

  1. Research on monitoring technology of axial gap change about high-speed rotating machinery

    International Nuclear Information System (INIS)

    Zhang Xiaochan; Liu Fanglei; Hu Shihua; Xie Qing; Li Zhen

    2014-01-01

    This paper describes that the only measuring point of high-speed rotating machinery (speed monitoring transducer) measuring the operation of the axial gap change and application. According to mechanism analysis the speed monitoring transducer's signal, prove its amplitude changes including the axial gap change information. To carry out the speed monitoring transducer qualitative and quantitative axial gap change research, Find the output signal amplitude and clearance change corresponding relationship formula of speed monitoring transducer, define the measurement method. Based on the above analsis, manufacture the single channel measurement devices and multiple unit measurement system, provide an important fault decision of high-speed rotating machinery, it can be applied to new equipment development and production. (authors)

  2. Approach to improve the axial power distribution for the application of a core protection system

    International Nuclear Information System (INIS)

    Koo, Bon Seung; Cho, Jin Young; Song, Jae Seung; Lee, Chung Chan

    2008-01-01

    A Core Protection Calculator System (CPCS) is a digital computer based on a safety system for generating trip signals based on a calculation of the Departure from Nucleate Boiling Ratio (DNBR) and the Local Power Density (LPD) by using several on-line measured system parameters including 3-level ex-core detector signals. A few approaches to improve the axial power distribution for the application of a core protection system were performed. For the Yonggwang unit 3 (cycle 1), axial power distributions were synthesized by applying the cubic spline method and compared with the neutronics code results. Several new cubic spline function sets were generated for the drastically distorted axial shapes for a 3-level ex-core detector system. In addition, synthesized axial shapes with a 5-level ex-core detector signals were compared with the conventional 3-level detector results. It demonstrates that the newly generated function sets appear to be better than that of the conventional CPC from the aspect of an axial power synthesis, particularly for the heavily distorted shapes. Moreover, synthesis of an axial power distribution using 5-level ex-core detector signals appears to be better than that of the 3-level ex-core detector signals. From the above results, improvement of the thermal margin is expected because of an uncertainty decreasing a core protection system. (authors)

  3. Numerical simulation of the tip clearance flow in axial turbomachinery; Numerische Simulation der Stroemung im radialen Schaufelspalt axialer Turbomaschinen

    Energy Technology Data Exchange (ETDEWEB)

    Melake, A [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Koeln (Germany). Inst. fuer Antriebstechnik

    1997-12-31

    A computer program has been developed to calculate the three-dimensional tip leakage flow in axial turbomachinery based on the Navier-Stokes equation. This program has been applied to investigate the leakage flow within the gap between the blade fip and casing in an annular compressor cascade. A block structured computational mesh has been used in order to resolve the flow details within the gap and the passage flow. Flow characteristics like boundary layer separation, vortex genesis and interaction of the leakage flow with the secondary flow have been investigated and compared with existing experimental data. By varying the incidence angle and the tip gap the above mentioned flow phenomena have been analysed in an annular compressor cascade and a shrouded propfan rotor respectively. Furthermore, the relationship between the total pressure loss, the axial velocity deficit and the divergence of the tip leakage vortex has been investigated. Streamlines, limited streamlines and the critical point theory have been used extensively to analyse the boundary layer separation on the casing and its roll up to form the tip clearance vortex. (orig.). 59 figs., 3 tabs., 110 refs. [Deutsch] Es wurde ein Rechenprogramm zur Berechnung der dreidimensionalen Spaltstroemung im radialen Schaufelspalt axialer Turbomaschinen auf der Basis der Navier-Stokes`schen Gleichungen entwickelt und angewendet. Um die Stroemung innerhalb des Spaltes und der Schaufelpassage besser aufloesen zu koennen, wurde eine blockstrukturierte Netztopologie verwendet. Stroemungseigenschaften wie Grenzschichtabloesung, Entstehung des Spaltwirbels, Interaktion der Spaltstroemung mit der Sekundaerstroemung werden untersucht und mit vorhandenen experimentellen Daten verglichen. Im weiteren werden durch Variation der Inzidenz und der Spaltweite die oben genannten Stroemungsphaenomene an einem axialen Verdichterringgitter und an einem ummantelten Propfan analysiert. Ferner werden die Korrelation zwischen

  4. Experimental Study of Axially Tension Cold Formed Steel Channel Members

    Science.gov (United States)

    Apriani, Widya; Lubis, Fadrizal; Angraini, Muthia

    2017-12-01

    Experimental testing is commonly used as one of the steps to determine the cause of the collapse of a building structure. The collapse of structures can be due to low quality materials. Although material samples have passed laboratory tests and the existing technical specifications have been met but there may be undetected defects and known material after failure. In this paper will be presented Experimental Testing of Axially Tension Cold Formed Steel Channel Members to determine the cause of the collapse of a building roof truss x in Pekanbaru. Test of tensile strength material cold formed channel sections was performed to obtain the main characteristics of Cold Formed steel material, namely ultimate tensile strength loads that can be held by members and the yield stress possessed by channel sections used in construction. Analysis of axially tension cold formed steel channel section presents in this paper was conducted through experimental study based on specificationsAnnualBook of ASTM Standards: Metal Test methods and Analitical Procedures, Section 3 (1991). The result of capacity loads experimental test was compared with design based on SNI 03-7971-2013standard of Indonesia for the design of cold formed steel structural members. The results of the yield stress of the material will be seen against the minimum allowable allowable stress range. After the test, the percentace of ultimate axial tension capacity theory has a result that is 16.46% larger than the ultimate axial tension capacity experimental. When compared with the load that must be borne 5.673 kN/m it can be concluded that 2 specimens do not meet. Yield stress of member has fulfilled requirement that wass bigger than 550 MPa. Based on the curve obtained ultimate axial tension capacity theory, results greater than experimental. The greatest voltage value (fu) is achieved under the same conditions as its yield stress. For this specimen with a melting voltage value fy = 571.5068 MPa has fulfilled the

  5. Axial distribution of absorbed doses in fast neutron field at the RB reactor

    International Nuclear Information System (INIS)

    Sokcic-Kostic, M.; Pesic, M.; Antic, D.; Ninkovic, M.

    1988-11-01

    The coupled fast thermal system CFTS at the RB reactor is created for obtaining fast neutron fields. The axial distribution of fast neutron flux density in its second configuration (CFTS-2) is measured. The axial distribution of absorbed doses is computed on the basis of mentioned experimental results. At the end these experimental and computed results are given. (Author)

  6. Axial and focal-plane diffraction catastrophe integrals

    International Nuclear Information System (INIS)

    Berry, M V; Howls, C J

    2010-01-01

    Exact expressions in terms of Bessel functions are found for some of the diffraction catastrophe integrals that decorate caustics in optics and mechanics. These are the axial and focal-plane sections of the elliptic and hyperbolic umbilic diffraction catastrophes, and symmetric elliptic and hyperbolic unfoldings of the X 9 diffraction catastrophes. These representations reveal unexpected relations between the integrals.

  7. The axial polarizability of nucleons and nuclei

    International Nuclear Information System (INIS)

    Ericson, M.; Figureau, A.

    1981-02-01

    The part of the static nuclear axial polarizability arising from the nucleonic excitations is derived from the low energy expansion of the πN amplitude. It is shown that the contribution of the Δ intermediate state, though dominant, does not saturate the nucleonic response. A similar effect, though more pronounced, is known to occur for the magnetic susceptibility

  8. Axial displacement of external and internal implant-abutment connection evaluated by linear mixed model analysis.

    Science.gov (United States)

    Seol, Hyon-Woo; Heo, Seong-Joo; Koak, Jai-Young; Kim, Seong-Kyun; Kim, Shin-Koo

    2015-01-01

    To analyze the axial displacement of external and internal implant-abutment connection after cyclic loading. Three groups of external abutments (Ext group), an internal tapered one-piece-type abutment (Int-1 group), and an internal tapered two-piece-type abutment (Int-2 group) were prepared. Cyclic loading was applied to implant-abutment assemblies at 150 N with a frequency of 3 Hz. The amount of axial displacement, the Periotest values (PTVs), and the removal torque values(RTVs) were measured. Both a repeated measures analysis of variance and pattern analysis based on the linear mixed model were used for statistical analysis. Scanning electron microscopy (SEM) was used to evaluate the surface of the implant-abutment connection. The mean axial displacements after 1,000,000 cycles were 0.6 μm in the Ext group, 3.7 μm in the Int-1 group, and 9.0 μm in the Int-2 group. Pattern analysis revealed a breakpoint at 171 cycles. The Ext group showed no declining pattern, and the Int-1 group showed no declining pattern after the breakpoint (171 cycles). However, the Int-2 group experienced continuous axial displacement. After cyclic loading, the PTV decreased in the Int-2 group, and the RTV decreased in all groups. SEM imaging revealed surface wear in all groups. Axial displacement and surface wear occurred in all groups. The PTVs remained stable, but the RTVs decreased after cyclic loading. Based on linear mixed model analysis, the Ext and Int-1 groups' axial displacements plateaued after little cyclic loading. The Int-2 group's rate of axial displacement slowed after 100,000 cycles.

  9. Taming axial dispersion in hydrodynamic chromatography columns through wall patterning

    Science.gov (United States)

    Adrover, Alessandra; Cerbelli, Stefano; Giona, Massimiliano

    2018-04-01

    A well-known limitation of hydrodynamic chromatography arises from the synergistic interaction between transverse diffusion and streamwise convection, which enhances axial dispersion through the Taylor-Aris mechanism. We show that a periodic sequence of slip/no-slip conditions at the channel walls (e.g., representing wall indentations hosting stable air pockets) can significantly reduce axial dispersion, thus enhancing separation performance. The theoretical/numerical analysis is based on a generalization of Brenner's macrotransport approach to solute transport, here modified to account for the finite-size of the suspended particles. The most effective dispersion-taming outcome is observed when the alternating sequence of slip/no-slip conditions yields non-vanishing cross-sectional flow components. The combination of these components with the hindering interaction between the channel boundaries and the finite-sized particles gives rise to a non-trivial solution of Brenner's problem on the unit periodic cell, where the cross-sectional particle number density departs from the spatially homogeneous condition. In turn, this effect impacts upon the solution of the so-called b-field defining the large-scale dispersion tensor, with an overall decremental effect on the axial dispersion coefficient and on the Height Equivalent of a Theoretical Plate.

  10. Accretion mode of oceanic ridges governed by axial mechanical strength

    Science.gov (United States)

    Sibrant, A. L. R.; Mittelstaedt, E.; Davaille, A.; Pauchard, L.; Aubertin, A.; Auffray, L.; Pidoux, R.

    2018-04-01

    Oceanic spreading ridges exhibit structural changes as a function of spreading rate, mantle temperature and the balance of tectonic and magmatic accretion. The role that these or other processes have in governing the overall shape of oceanic ridges is unclear. Here, we use laboratory experiments to simulate ridge spreading in colloidal aqueous dispersions whose rheology evolves from purely viscous to elastic and brittle when placed in contact with a saline water solution. We find that ridge shape becomes increasingly linear with spreading rate until reaching a minimum tortuosity. This behaviour is predicted by the axial failure parameter ΠF, a dimensionless number describing the balance of brittle and plastic failure of axial lithosphere. Slow-spreading, fault-dominated and fast-spreading, fluid intrusion-dominated ridges on Earth and in the laboratory are separated by the same critical ΠF value, suggesting that the axial failure mode governs ridge geometry. Values of ΠF can also be calculated for different mantle temperatures and applied to other planets or the early Earth. For higher mantle temperatures during the Archaean, our results preclude the predicted formation of large tectonic plates at high spreading velocity.

  11. Research on a novel high stiffness axial passive magnetic bearing for DGMSCMG

    International Nuclear Information System (INIS)

    Sun, Jinji; Wang, Chun'e; Le, Yun

    2016-01-01

    To increase the displacement stiffness and decrease power loss of double gimbals magnetically suspended control momentum gyro (DGMSCMG), this paper researches a new structure of axial passive magnetic bearing (APMB). Different from the existing APMB, the proposed APMB is composed of segmented permanent magnets and magnetic rings. The displacement stiffness and angular stiffness expressions are derived by equivalent magnetic circuit method and infinitesimal method based on the end magnetic flux. The relationships are analyzed between stiffness and structure parameters such as length of air gap, length of permanent magnet, height of permanent magnet and end length of magnetic ring. Besides, the axial displacement stiffness measurement method of the APMB is proposed, and it verified the correctness of proposed theoretical method. The DGMSCMG prototype is manufactured and the slow-down characteristic experiment is carried out, and the experimental result reflects the low power loss feature of the APMB. - Highlights: • A novel high stiffness axial passive magnetic bearing for DGMSCMG. • The proposed APMB is composed of segmented permanent magnets and magnetic rings. • The APMB is analyzed by EMCM and infinitesimal method based on the end magnetic flux. • The axial displacement stiffness measurement method of the APMB is proposed. • The DGMSCMG is manufactured and proved the correctness of theoretical analysis.

  12. Detection of pulmonary nodules at paediatric CT: maximum intensity projections and axial source images are complementary

    International Nuclear Information System (INIS)

    Kilburn-Toppin, Fleur; Arthurs, Owen J.; Tasker, Angela D.; Set, Patricia A.K.

    2013-01-01

    Maximum intensity projection (MIP) images might be useful in helping to differentiate small pulmonary nodules from adjacent vessels on thoracic multidetector CT (MDCT). The aim was to evaluate the benefits of axial MIP images over axial source images for the paediatric chest in an interobserver variability study. We included 46 children with extra-pulmonary solid organ malignancy who had undergone thoracic MDCT. Three radiologists independently read 2-mm axial and 10-mm MIP image datasets, recording the number of nodules, size and location, overall time taken and confidence. There were 83 nodules (249 total reads among three readers) in 46 children (mean age 10.4 ± 4.98 years, range 0.3-15.9 years; 24 boys). Consensus read was used as the reference standard. Overall, three readers recorded significantly more nodules on MIP images (228 vs. 174; P < 0.05), improving sensitivity from 67% to 77.5% (P < 0.05) but with lower positive predictive value (96% vs. 85%, P < 0.005). MIP images took significantly less time to read (71.6 ± 43.7 s vs. 92.9 ± 48.7 s; P < 0.005) but did not improve confidence levels. Using 10-mm axial MIP images for nodule detection in the paediatric chest enhances diagnostic performance, improving sensitivity and reducing reading time when compared with conventional axial thin-slice images. Axial MIP and axial source images are complementary in thoracic nodule detection. (orig.)

  13. Nonlinear output feedback control of underwater vehicle propellers using feedback form estimated axial flow velocity

    DEFF Research Database (Denmark)

    Fossen, T. I.; Blanke, Mogens

    2000-01-01

    Accurate propeller shaft speed controllers can be designed by using nonlinear control theory and feedback from the axial water velocity in the propeller disc. In this paper, an output feedback controller is derived, reconstructing the axial flow velocity from vehicle speed measurements, using...... a three-state model of propeller shaft speed, forward (surge) speed of the vehicle, and the axial flow velocity. Lyapunov stability theory is used to prove that a nonlinear observer combined with an output feedback integral controller provide exponential stability. The output feedback controller...... compensates for variations in thrust due to time variations in advance speed. This is a major problem when applying conventional vehicle-propeller control systems, The proposed controller is simulated for an underwater vehicle equipped with a single propeller. The simulations demonstrate that the axial water...

  14. O valor da fase sem contraste na tomografia computadorizada do abdome The role of the unenhanced phase in the routine abdominal computed tomography

    Directory of Open Access Journals (Sweden)

    Ana Paula Klautau Leite

    2008-10-01

    Full Text Available OBJETIVO: Determinar o valor agregado da fase sem meio de contraste da tomografia computadorizada do abdome em pacientes sem diagnóstico determinado ou em estadiamento tumoral. MATERIAIS E MÉTODOS: Estudo prospectivo e transversal em 100 pacientes consecutivos submetidos a tomografia computadorizada abdominal sem e com meio de contraste intravenoso. Dois examinadores avaliaram todos os exames, procurando estabelecer, através da fase com meio de contraste intravenoso (primeira análise e posteriormente através da fase sem contraste (segunda análise, o diagnóstico principal e os secundários em função da indicação clínica do exame. Mediu-se a freqüência de mudança diagnóstica decorrente da análise combinada das fases pré- e pós-contraste intravenoso. Casos que tiveram mudança diagnóstica foram avaliados por especialistas clínicos para determinar se implicaria mudanças de conduta. RESULTADOS: Diagnósticos principal e secundário foram modificados em 1 e 18 casos, respectivamente (p = 1,000; p = 0,143. Os diagnósticos modificados foram: esteatose, definição de nódulo em adrenal, nefrolitíase, classificação de cistos renais e calcificação hepática. Nos casos em que a fase sem contraste modificou o diagnóstico, os especialistas mudaram sua conduta em 14/19 (73% dos pacientes (p = 0,038. CONCLUSÃO: A fase sem contraste não modificou significativamente o diagnóstico principal ou secundário. Porém, as mudanças nos diagnósticos secundários influenciaram na conduta adotada pelos especialistas.OBJECTIVE: To determine the role of the unenhanced phase of abdominal computed tomography in patients without a definite diagnosis or undergoing tumor staging. MATERIALS AND METHODS: A prospective and transversal study was developed with 100 consecutive patients submitted to unenhanced and contrast-enhanced abdominal computed tomography. Two observers evaluated all the computed tomography images in the contrast-enhanced phase

  15. On aspects of vibration of axially moving continua

    NARCIS (Netherlands)

    Hageraats-Ponomareva, S.

    2009-01-01

    In axially moving structures like conveyor belt systems, magnetic tapes, and so on, vibrations occur due to the presence of different kinds of imperfections in the systems. For these structures internal resonances can lead to severe vibrations. Resonance free conveyor belt systems can be constructed

  16. NORMAL AXIAL ANGLES OF THE KNEE JOINT IN ADULT ...

    African Journals Online (AJOL)

    hi-tech

    2003-08-01

    Aug 1, 2003 ... Conclusion: Our study has demonstrated comparative variations in means and ranges of normal axial angles .... population was significantly different from the mean ... case, however, the angle also exhibits racial variations.

  17. A high resolution TOF-PET concept with axial geometry and digital SiPM readout

    CERN Document Server

    Casella, C; Joram, C; Schneider, T

    2014-01-01

    The axial arrangement of long scintillation crystals is a promising concept in PET instrumentation to address the need for optimized resolution and sensitivity. Individual crystal readout and arrays of wavelength shifter strips placed orthogonally to the crystals lead to a 3D-detection of the annihilations photons. A fully operational demonstrator scanner, developed by the AX-PET collaboration, proved the potential of this concept in terms of energy and spatial resolution as well as sensitivity. This paper describes a feasibility study, performed on axial prototype detector modules with 100 mm long LYSO crystals, read out by the novel digital Silicon Photomultipliers (dSiPM) from Philips. With their highly integrated readout electronics and excellent intrinsic time resolution, dSiPMs allow for compact, axial detector modules which may extend the potential of the axial PET concept by time of fl ight capabilities (TOF-PET). A coincidence time resolution of 211 ps (FWHM) was achieved in the coincidence of two ax...

  18. Dynamics and stability of transverse vibrations of nonlocal nanobeams with a variable axial load

    International Nuclear Information System (INIS)

    Li, C; Yu, J L; Lim, C W

    2011-01-01

    This paper investigates the natural frequency, steady-state resonance and stability for the transverse vibrations of a nanobeam subjected to a variable initial axial force, including axial tension and axial compression, based on nonlocal elasticity theory. It is reported that the nonlocal nanoscale has significant effects on vibration behavior, which results in a new effective nonlocal bending moment different to but dependent on the corresponding nonlocal bending moment. The effects of nonlocal nanoscale and the variation of initial axial force on the natural frequency as well as the instability regions are analyzed by the perturbation method. It concludes that both the nonlocal nanoscale and the initial tension, including static and dynamic tensions, cause an increase in natural frequency, while an initial compression causes the natural frequency to decrease. Instability regions are also greatly influenced by the nonlocal nanoscale and initial tension and they become smaller with stronger nonlocal effects or larger initial tension

  19. Calculation of the Nucleon Axial Form Factor Using Staggered Lattice QCD

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, Aaron S. [Fermilab; Hill, Richard J. [Perimeter Inst. Theor. Phys.; Kronfeld, Andreas S. [Fermilab; Li, Ruizi [Indiana U.; Simone, James N. [Fermilab

    2016-10-14

    The nucleon axial form factor is a dominant contribution to errors in neutrino oscillation studies. Lattice QCD calculations can help control theory errors by providing first-principles information on nucleon form factors. In these proceedings, we present preliminary results on a blinded calculation of $g_A$ and the axial form factor using HISQ staggered baryons with 2+1+1 flavors of sea quarks. Calculations are done using physical light quark masses and are absolutely normalized. We discuss fitting form factor data with the model-independent $z$ expansion parametrization.

  20. The axial power distribution validation of the SCWR fuel assembly with coupled neutronics-thermal hydraulics method

    Energy Technology Data Exchange (ETDEWEB)

    Xi, Xi [CNNC Key Laboratory on Nuclear Reactor Thermal Hydraulics Technology, Nuclear Power Institute of China, Chengdu 610041 (China); Xiao, Zejun, E-mail: fabulous_2012@sina.com [CNNC Key Laboratory on Nuclear Reactor Thermal Hydraulics Technology, Nuclear Power Institute of China, Chengdu 610041 (China); Yan, Xiao; Li, Yongliang; Huang, Yanping [CNNC Key Laboratory on Nuclear Reactor Thermal Hydraulics Technology, Nuclear Power Institute of China, Chengdu 610041 (China)

    2013-05-15

    Highlights: ► CFX and MCNP codes are suitable to calculate the axial power profile of the FA. ► The partition method in the calculation will affect the final result. ► The density feedback has little effect on the axial power profile of CSR1000 FA. -- Abstract: SCWR (super critical water reactor) is one of the IV generation nuclear reactors in the world. In a typical SCWR the water enters the reactor from the cold leg with a temperature of 280 °C and then leaves the core with a temperature of 500 °C. Due to the sharp change in temperature, there is a huge density change of the water along the axial direction of the fuel assembly (FA), which will affect the moderating power of the water. So the axial power distribution of the SCWR FA could be different from the traditional PWR FA.In this paper, it is the first time that the thermal hydraulics code CFX and neutronics code MCNP are used to analyze the axial power distribution of the SCWR FA. First, the factors in the coupled method which could affect the result are analyzed such as the initialization value or the partition method especially in the MCNP code. Then the axial power distribution of the Europe HPLWR FA is obtained by the coupled method with the two codes and the result is compared with that obtained by Waata and Reiss. There is a good agreement among the three kinds of results. At last, this method is used to calculate the axial power distribution of the Chinese SCWR (CSR1000) FA. It is found the axial power profile of the CSR1000 FA is not so sensitive to the change of the moderator density.

  1. An immediate effect of axial neck rotation training with real time visual feedback using a smartphone inclinometer on improvement in axial neck rotation function.

    Science.gov (United States)

    Park, Kyue-Nam; Kwon, Oh-Yun; Kim, Si-Hyun; Jeon, In-Cheol

    2017-03-01

    The purpose of this study was to compare the immediate effects of axial neck rotation training (Axi-NRT) with and without real-time visual feedback (VF) using a smartphone inclinometer on the range of motion (ROM) for axial neck rotation and the onset of compensatory neck lateral bending and extension during active neck rotation. Twenty participants with restricted ROM for neck rotation but no neck pain (21.1 ± 1.6 years and 8 males, 12 females) were recruited for Axi-NRT with VF, and twenty age- and gender-matched participants with restricted ROM for neck rotation were recruited for Axi-NRT without VF. Changes in ROM for neck rotation and the onset time of compensatory neck movement during active neck rotation were measured using an electromagnetic tracking system. Axi-NRT with VF was more effective in increasing ROM for neck rotation and decreasing and delaying the onset of compensatory neck movements during active neck rotation compared with Axi-NRT without VF. Repeated Axi-NRT using VF is useful to educate participants in maintaining the axis of the cervical spine and to increase ROM for axial neck rotation with less compensatory neck motion in participants with a restricted range of neck rotations.

  2. Diagnostic value of multidetector row CT in rectal cancer staging: comparison of multiplanar and axial images with histopathology

    International Nuclear Information System (INIS)

    Sinha, R.; Verma, R.; Rajesh, A.; Richards, C.J.

    2006-01-01

    Aim: Although magnetic resonance (MR) imaging is widely used for rectal cancer staging, many centres in the UK perform computed tomography (CT) for staging rectal cancer at present. Furthermore in a small proportion of cases contraindications to MR imaging may lead to staging using CT. The purpose of this study was to evaluate the accuracy of current generation multidetector row CT (MDCT) in local staging of rectal cancer. In particular the accuracy of multiplanar (MPR) versus axial images in the staging of rectal cancer was assessed. Material and methods: Sixty-nine consecutive patients were identified who had undergone staging of rectal cancer on CT. The imaging data were reviewed as axial images and then as MPR images (coronal and sagittal) perpendicular and parallel to the tumour axis. CT staging on axial and MPR images was then compared to histopathological staging. Results: MPR images detected more T4 and T3 stage tumours than axial images alone. The overall accuracy of T-staging on MPR images was 87.1% versus 73.0% for axial images alone. The overall accuracy of N staging on MPR versus axial images was 84.8% versus 70.7%. There was a statistically significant difference in the staging of T3 tumours between MPR and axial images (p < 0.001). Conclusion: Multidetector row CT has high accuracy for local staging of rectal cancer. Addition of MPR images to standard axial images provides higher accuracy rates for T and N staging of rectal cancer than axial images alone

  3. The relation between anomalous magnetic moment and axial anomaly

    International Nuclear Information System (INIS)

    Teryaev, O.V.

    1990-12-01

    The conservation of total angular momentum of spinor particle leads to a simple relation between the famous Schwinger and Adler coefficients determining axial anomaly and anomalous magnetic moment, respectively. (author). 8 refs, 1 fig

  4. Axially modulated arch resonator for logic and memory applications

    KAUST Repository

    Hafiz, Md Abdullah Al; Tella, Sherif Adekunle; Alcheikh, Nouha; Fariborzi, Hossein; Younis, Mohammad I.

    2018-01-01

    We demonstrate reconfigurable logic and random access memory devices based on an axially modulated clamped-guided arch resonator. The device is electrostatically actuated and the motional signal is capacitively sensed, while the resonance frequency

  5. Bone Disease in Axial Spondyloarthritis.

    Science.gov (United States)

    Van Mechelen, Margot; Gulino, Giulia Rossana; de Vlam, Kurt; Lories, Rik

    2018-05-01

    Axial spondyloarthritis is a chronic inflammatory skeletal disorder with an important burden of disease, affecting the spine and sacroiliac joints and typically presenting in young adults. Ankylosing spondylitis, diagnosed by the presence of structural changes to the skeleton, is the prototype of this disease group. Bone disease in axial spondyloarthritis is a complex phenomenon with the coexistence of bone loss and new bone formation, both contributing to the morbidity of the disease, in addition to pain caused by inflammation. The skeletal structural changes respectively lead to increased fracture risk and to permanent disability caused by ankylosis of the sacroiliac joints and the spine. The mechanism of this new bone formation leading to ankylosis is insufficiently known. The process appears to originate from entheses, specialized structures that provide a transition zone in which tendon and ligaments insert into the underlying bone. Growth factor signaling pathways such as bone morphogenetic proteins, Wnts, and Hedgehogs have been identified as molecular drivers of new bone formation, but the relationship between inflammation and activation of these pathways remains debated. Long-standing control of inflammation appears necessary to avoid ankylosis. Recent evidence and concepts suggest an important role for biomechanical factors in both the onset and progression of the disease. With regard to new bone formation, these processes can be understood as ectopic repair responses secondary to inflammation-induced bone loss and instability. In this review, we discuss the clinical implications of the skeletal changes as well as the underlying molecular mechanisms, the relation between inflammation and new bone formation, and the potential role of biomechanical stress.

  6. Evaluation of electromagnetic shielding effectiveness of multi-axial ...

    Indian Academy of Sciences (India)

    2016-08-26

    Aug 26, 2016 ... ... Lecture Workshops · Refresher Courses · Symposia. Home; Journals; Bulletin of Materials Science; Volume 39; Issue 4. Evaluation of electromagnetic shielding effectiveness of multi-axial fabrics and their reinforced PES composites. RAMAZAN ERDEM. Volume 39 Issue 4 August 2016 pp 963-970 ...

  7. Axial Torsion of Gangrenous Meckel's Diverticulum Causing Small ...

    African Journals Online (AJOL)

    dividing the band. Resection and anastomosis of the small bowel including the MD was performed. We hereby report a rare and unusual complication of a MD. Although treatment outcome is generally good, pre-operative diagnosis is often difficult. Key words: Axial torsion, Meckel's diverticulum, small bowel obstruction.

  8. Limb flexion-induced axial compression and bending in human femoropopliteal artery segments.

    Science.gov (United States)

    Poulson, William; Kamenskiy, Alexey; Seas, Andreas; Deegan, Paul; Lomneth, Carol; MacTaggart, Jason

    2018-02-01

    High failure rates of femoropopliteal artery (FPA) interventions are often attributed in part to severe mechanical deformations that occur with limb movement. Axial compression and bending of the FPA likely play significant roles in FPA disease development and reconstruction failure, but these deformations are poorly characterized. The goal of this study was to quantify axial compression and bending of human FPAs that are placed in positions commonly assumed during the normal course of daily activities. Retrievable nitinol markers were deployed using a custom-made catheter system into 28 in situ FPAs of 14 human cadavers. Contrast-enhanced, thin-section computed tomography images were acquired with each limb in the standing (180 degrees), walking (110 degrees), sitting (90 degrees), and gardening (60 degrees) postures. Image segmentation and analysis allowed relative comparison of spatial locations of each intra-arterial marker to determine axial compression and bending using the arterial centerlines. Axial compression in the popliteal artery (PA) was greater than in the proximal superficial femoral artery (SFA) or the adductor hiatus (AH) segments in all postures (P = .02). Average compression in the SFA, AH, and PA ranged from 9% to 15%, 11% to 19%, and 13% to 25%, respectively. The FPA experienced significantly more acute bending in the AH and PA segments compared with the proximal SFA (P < .05) in all postures. In the walking, sitting, and gardening postures, average sphere radii in the SFA, AH, and PA ranged from 21 to 27 mm, 10 to 18 mm, and 8 to 19 mm, whereas bending angles ranged from 150 to 157 degrees, 136 to 147 degrees, and 137 to 148 degrees, respectively. The FPA experiences significant axial compression and bending during limb flexion that occur at even modest limb angles. Moreover, different segments of the FPA appear to undergo significantly different degrees of deformation. Understanding the effects of limb flexion on axial compression and

  9. One-loop calculations in QED in axial gauge

    International Nuclear Information System (INIS)

    Boos, E.E.; Kurannoy, S.S.

    1983-01-01

    The present paper pursued the aim to test at the simple example of the calculation of the anomalous magnetic moment in quantum electrodynamics the methods of calculating one-loop integrals in the axial gauge, using the dimensional regularization, and to investigate the independence of the results on the choice of the recipe of how to treat the poles in the denominators (k eta) -1 . It is shown that the techniques developed in another paper, as well as in the present paper, can be successfully applied in such calculations, in spite of the peculiarities of the axial gauge that have been discussed previously. The results of the two different ways of treating singularities (k eta) -1 (the principal value and 't Hooft's prescription) turn out to be equal. At the same time it was verified that the Green functions obtained by these calculations near the mass shell in the one-loop approximation satisfy the ward identity

  10. Axial flux permanent magnet brushless machines

    CERN Document Server

    Gieras, Jacek F; Kamper, Maarten J

    2008-01-01

    Axial Flux Permanent Magnet (AFPM) brushless machines are modern electrical machines with a lot of advantages over their conventional counterparts. They are being increasingly used in consumer electronics, public life, instrumentation and automation system, clinical engineering, industrial electromechanical drives, automobile manufacturing industry, electric and hybrid electric vehicles, marine vessels and toys. They are also used in more electric aircrafts and many other applications on larger scale. New applications have also emerged in distributed generation systems (wind turbine generators

  11. An investigation of inconsistent projections and artefacts in multi-pinhole SPECT with axially aligned pinholes

    International Nuclear Information System (INIS)

    Kench, P L; Meikle, S R; Lin, J; Gregoire, M C

    2011-01-01

    Multiple pinholes are advantageous for maximizing the use of the available field of view (FOV) of compact small animal single photon emission computed tomography (SPECT) detectors. However, when the pinholes are aligned axially to optimize imaging of extended objects, such as rodents, multiplexing of the pinhole projections can give rise to inconsistent data which leads to 'ghost point' artefacts in the reconstructed volume. A novel four pinhole collimator with a baffle was designed and implemented to eliminate these inconsistent projections. Simulation and physical phantom studies were performed to investigate artefacts from axially aligned pinholes and the efficacy of the baffle in removing inconsistent data and, thus, reducing reconstruction artefacts. SPECT was performed using a Defrise phantom to investigate the impact of collimator design on FOV utilization and axial blurring effects. Multiple pinhole SPECT acquired with a baffle had fewer artefacts and improved quantitative accuracy when compared to SPECT acquired without a baffle. The use of four pinholes positioned in a square maximized the available FOV, increased acquisition sensitivity and reduced axial blurring effects. These findings support the use of a baffle to eliminate inconsistent projection data arising from axially aligned pinholes and improve small animal SPECT reconstructions.

  12. Construction of axial chirality by rhodium-catalyzed asymmetric dehydrogenative Heck coupling of biaryl compounds with alkenes.

    Science.gov (United States)

    Zheng, Jun; You, Shu-Li

    2014-11-24

    Enantioselective construction of axially chiral biaryls by direct C-H bond functionalization reactions has been realized. Novel axially chiral biaryls were synthesized by the direct C-H bond olefination of biaryl compounds, using a chiral [Cp*Rh(III)] catalyst, in good to excellent yields and enantioselectivities. The obtained axially chiral biaryls were found as suitable ligands for rhodium-catalyzed asymmetric conjugate additions. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Tomografia computadorizada no diagnóstico da otosclerose retrofenestral Computed tomography in the diagnosis of retrofenestral otosclerosis

    Directory of Open Access Journals (Sweden)

    Andy de Oliveira Vicente

    2004-01-01

    Full Text Available OBJETIVO: Identificar os principais achados tomográficos da otosclerose retrofenestral. MÉTODO: Estudo prospectivo multicêntrico com tomografia computadorizada (TC de ossos temporais em 54 pacientes com diagnóstico clínico e cirúrgico de otosclerose. Foi realizada uma análise tomográfica, em que foi avaliada a utilidade da TC no diagnóstico radiológico da otosclerose retrofenestral, sendo verificados os principais sítios de lesões dessa doença. Foram incluídos neste estudo 22 pacientes submetidos à TC de ossos temporais para investigação de outras afecções otológicas, que constituíram o grupo controle. RESULTADOS: Os achados tomográficos foram bilaterais na maioria dos casos e o foco retrofenestral mais prevalente foi o foco pericoclear. CONCLUSÕES: A TC monstrou-se útil na identificação dos focos retrofenestrais. A evidência tomográfica desses focos juntamente com o envolvimento endosteal da cóclea podem sugerir uma maior atividade da doença.AIM: To identify the main tomographic findings of retrofenestral otosclerosis. METHODS: A prospective and multicentric study using computed tomography (CT of the temporal bone in 54 patients with a clinical and surgical diagnosis of otosclerosis. A tomographic analysis has been performed to evaluate the utility of CT scans in diagnosing retrofenestral otosclerosis, verifying the sites of predilection for otosclerotic lesions. In this study, 22 patients undergone CT scans of temporal bones have been included in order to investigate other otologic diseases and have constituted the control group. RESULTS: The tomographic findings were mostly bilateral and the retrofenestral focus more prevalent was the pericochlear focus. CONCLUSIONS: The CT scan was useful in the identification of the retrofenestral focuses. The evidence of this focuses and the presence of the endosteal involvement of the cochlea can suggest a higher activity of the disease.

  14. The Influence of the Axial Magnetic Field Upon- the Coaxial Plasma Gun Parameters

    International Nuclear Information System (INIS)

    El-Aragi, G.M.; El-Demardash, A.

    2001-01-01

    This study concerns with the influence of an applied axial magnetic field upon the electrical parameters and on the brightness (luminance) of argon plasma. The brightness was measured by with a photomultiplier type of IP28 RCA. The experimental results are investigated with plasma gun device operated with argon gas at a pressure of 3.5 Torr. An axial time independent magnetic field with intensity of 550 G is introduced along the plasma current sheath axial region, within the annular space between the two coaxial electrodes. From the measurements of the discharge current I(t) and the voltage V(t), the electrical discharge parameters of the plasma gun device and the plasma current sheath implosion velocity are estimated, in normal mode of plasma gun operation and in the mode of presence external axial magnetic field. A comparison between these two modes is studied. It was found that the thickness of skin-layer δ about 0.01 cm and the wavelength λ, of the perturbation about 1.3 cm i.e. the instability has been satisfied. The growth rate γ of the instability about 10 6 sec -1 . (author)

  15. Assessment of Axial Behavior of Circular HPFRCC Members Externally Confined with FRP Sheets

    Directory of Open Access Journals (Sweden)

    Ugur Demir

    2018-01-01

    Full Text Available The aim of this paper is to identify the axial behavior characteristics of FRP (fiber reinforced polymer confined circular HPFRCC (high performance fiber reinforced cementitious composite members under compression. The test program comprised of 24 circular specimens with an average compressive strength of 102.7 MPa, including 21 carbon FRP (CFRP confined (2, 4, 6, 8 and 10 layers and three unconfined specimens. Transverse confinement generated by external FRP sheets resulted with a remarkable enhancement in axial strength and deformability, which is extremely important to resist seismic actions. The higher was the thickness of FRP confinement, the larger was the ultimate strain (εcu and peak compressive strength (f′cc of externally confined HPFRCC. When compared to FRP confined conventional concrete, different axial and lateral deformation characteristics were seen in FRP jacketed HPFRCC members. Higher strength and steel fiber presence in HPFRCC limited the lateral deformations which resulted with reduced strain efficiency with respect to conventional concrete. After presenting the experimental work, performance and accuracy of several available models proposed for predicting the axial behavior of FRP jacketed concrete were evaluated in a comparative manner.

  16. Influence of axial movement on fatigue of PROFILE* NI-TI rotary instruments: an in vitro evaluation

    Science.gov (United States)

    Avoaka, Marie-Chantal; Haïkel, Youssef

    2010-01-01

    The aim of this study was to evaluate the influence of the axial movement and the angle of curve (in degrees) on fatigue of nickel-titanium (Ni-Ti) ProFile’ rotary endodontic instruments. Ni-Ti ProFile’ rotary instruments (Maillefer SA, Ballaigues, Switzerland), 25 mm long in the range of ISO size 15 to 40 with two tapers (0.4 and 0.6) were evaluated. They are divided in two groups: the instruments with axial movement and those without axial movement. The system used to test the fatigue is maintained in mechanical conditions as close as possible to the clinical situation. The axial movement is in the order of 2mm in corono-apical direction with a frequency of 1Hz. The concave radii incorporating a notched V-form for guiding the instruments were: 5; 7,5 and 10 mm. The rotary system is mounted on an electric handpiece and rotated at 350 rpm speed as recommended by the manufacturers. The instruments are rotated until their separation, and the time, in seconds, is recorded. Statístícal evaluation is undertaken using a two-way t-test to identify significant differences between variables in the study (p engine drive ProFile’ instruments incorporating an axial movement and the instruments without axial movement with the same radius of curvature, size and taper. The incorporation of the axial movement increases significantly the life-span of the ProFile’ rotary instruments. This should reduce the risk of the instrument separation during the endodontic treatment. PMID:20507289

  17. Axial contraction in etched optical fiber due to internal stress reduction.

    Science.gov (United States)

    Lim, Kok-Sing; Yang, Hang-Zhou; Chong, Wu-Yi; Cheong, Yew-Ken; Lim, Chin-Hong; Ali, Norfizah M; Ahmad, Harith

    2013-02-11

    When an optical fiber is dipped in an etching solution, the internal stress profile in the fiber varies with the fiber diameter. We observed a physical contraction as much as 0.2% in the fiber axial dimension when the fiber was reduced from its original diameter to ~6 µm through analysis using high resolution microscope images of the grating period of an etched FBG at different fiber diameters. This axial contraction is related to the varying axial stress profile in the fiber when the fiber diameter is reduced. On top of that, the refractive index of fiber core increases with reducing fiber diameter due to stress-optic effect. The calculated index increment is as much as 1.8 × 10(-3) at the center of fiber core after the diameter is reduced down to ~6 µm. In comparison with the conventional model that assumes constant grating period and neglects the variation in stress-induced index change in fiber core, our proposed model indicates a discrepancy as much as 3nm in Bragg wavelength at a fiber diameter of ~6 µm.

  18. Axial skeletal CT densitometry

    International Nuclear Information System (INIS)

    Lampmann, L.E.H.

    1982-01-01

    Since the discovery of the Roentgen ray a precise and accurate assessment of bone mineral content has been a challenge to many investigators. A number of methods have been developed but no one satisfied. Considering its technical possibilities computed tomography is very promising in determination of bone mineral content (BMC). The new modality enables BMC estimations in the axial skeletal trabecular bone. CT densitometry can be performed on a normal commercially available third generation whole body CT scanner. No dedicated device in a special clinical set-up is necessary. In this study 106 patients, most of them clinically suspected of osteoporosis, were examined. The new method CT densitometry has been evaluated. The results have been correlated to alternative BMC determination methods. (Auth.)

  19. Aspectos da tomografia de coerência óptica na doença de Stargardt: relato de caso Optical coherence tomography aspects of Stargardt's disease: case report

    Directory of Open Access Journals (Sweden)

    Enéias Bezerra Gouveia

    2006-08-01

    Full Text Available O termo fundus flavimaculatus (doença de Stargardt descreve um grupo de distrofias maculares hereditárias caracterizadas por múltiplos "flecks" amarelados em nível do epitélio pigmentar da retina. Os autores descrevem os achados de tomografia de coerência óptica (OCT em paciente portador de doença de Stargardt e sugerem que a OCT tem validade como exame subsidiário no estudo das características da retina de pacientes portadores da doença de Stargardt, embora estudos envolvendo maior número de pacientes sejam indicados para permitir traçar-se o perfil das alterações mais comuns nestes casos.The term fundus flavimaculatus (Stargardt disease describes a group of inherited macular dystrophies characterized by multiple yellow to yellow-white flecks at the level of the retinal pigment epithelium. The authors describe findings in the patient with Stargardt's disease using optical coherence tomography (OCT, and suggest the examination to be valid as subsidiary method in the study of the characteristics of the retina in Stargardt's disease patients, but studies involving a series of patients should be able to show the most frequent findings in these cases.

  20. Improving axial resolution in confocal microscopy with new high refractive index mounting media.

    Science.gov (United States)

    Fouquet, Coralie; Gilles, Jean-François; Heck, Nicolas; Dos Santos, Marc; Schwartzmann, Richard; Cannaya, Vidjeacoumary; Morel, Marie-Pierre; Davidson, Robert Stephen; Trembleau, Alain; Bolte, Susanne

    2015-01-01

    Resolution, high signal intensity and elevated signal to noise ratio (SNR) are key issues for biologists who aim at studying the localisation of biological structures at the cellular and subcellular levels using confocal microscopy. The resolution required to separate sub-cellular biological structures is often near to the resolving power of the microscope. When optimally used, confocal microscopes may reach resolutions of 180 nm laterally and 500 nm axially, however, axial resolution in depth is often impaired by spherical aberration that may occur due to refractive index mismatches. Spherical aberration results in broadening of the point-spread function (PSF), a decrease in peak signal intensity when imaging in depth and a focal shift that leads to the distortion of the image along the z-axis and thus in a scaling error. In this study, we use the novel mounting medium CFM3 (Citifluor Ltd., UK) with a refractive index of 1.518 to minimize the effects of spherical aberration. This mounting medium is compatible with most common fluorochromes and fluorescent proteins. We compare its performance with established mounting media, harbouring refractive indices below 1.500, by estimating lateral and axial resolution with sub-resolution fluorescent beads. We show furthermore that the use of the high refractive index media renders the tissue transparent and improves considerably the axial resolution and imaging depth in immuno-labelled or fluorescent protein labelled fixed mouse brain tissue. We thus propose to use those novel high refractive index mounting media, whenever optimal axial resolution is required.

  1. The reversed and normal flux contributions to axial dipole decay for 1880-2015

    Science.gov (United States)

    Metman, M. C.; Livermore, P. W.; Mound, J. E.

    2018-03-01

    The axial dipole component of Earth's internal magnetic field has been weakening since at least 1840, an effect widely believed to be attributed to the evolution of reversed flux patches (RFPs). These are regions on the core-mantle boundary (CMB) where the sign of radial flux deviates from that of the dominant sign of hemispheric radial flux. We study dipole change over the past 135 years using the field models gufm1, COV-OBS.x1 and CHAOS-6; we examine the impact of the choice of magnetic equator on the identification of reversed flux, the contribution of reversed and normal flux to axial dipole decay, and how reversed and normal field evolution has influenced the axial dipole. We show that a magnetic equator defined as a null-flux curve of the magnetic field truncated at spherical harmonic degree 3 allows us to robustly identify reversed flux, which we demonstrate is a feature of at least degree 4 or 5. Additionally, our results indicate that the evolution of reversed flux accounts for approximately two-thirds of the decay of the axial dipole, while one third of the decay is attributed to the evolution of the normal field. We find that the decay of the axial dipole over the 20th century is associated with both the expansion and poleward migration of reversed flux patches. In contrast to this centennial evolution, changes in the structure of secular variation since epoch 2000 indicate that poleward migration currently plays a much reduced role in the ongoing dipole decay.

  2. Improving axial resolution in confocal microscopy with new high refractive index mounting media.

    Directory of Open Access Journals (Sweden)

    Coralie Fouquet

    Full Text Available Resolution, high signal intensity and elevated signal to noise ratio (SNR are key issues for biologists who aim at studying the localisation of biological structures at the cellular and subcellular levels using confocal microscopy. The resolution required to separate sub-cellular biological structures is often near to the resolving power of the microscope. When optimally used, confocal microscopes may reach resolutions of 180 nm laterally and 500 nm axially, however, axial resolution in depth is often impaired by spherical aberration that may occur due to refractive index mismatches. Spherical aberration results in broadening of the point-spread function (PSF, a decrease in peak signal intensity when imaging in depth and a focal shift that leads to the distortion of the image along the z-axis and thus in a scaling error. In this study, we use the novel mounting medium CFM3 (Citifluor Ltd., UK with a refractive index of 1.518 to minimize the effects of spherical aberration. This mounting medium is compatible with most common fluorochromes and fluorescent proteins. We compare its performance with established mounting media, harbouring refractive indices below 1.500, by estimating lateral and axial resolution with sub-resolution fluorescent beads. We show furthermore that the use of the high refractive index media renders the tissue transparent and improves considerably the axial resolution and imaging depth in immuno-labelled or fluorescent protein labelled fixed mouse brain tissue. We thus propose to use those novel high refractive index mounting media, whenever optimal axial resolution is required.

  3. Evaluation of electromagnetic shielding effectiveness of multi-axial ...

    Indian Academy of Sciences (India)

    The usage of electrical and electronic equipments has been increasing in daily life, which has a potential hazardous impact on humans and other living organisms. In this paper, multi-axial fabrics containing steel yarns and carbon filaments, and their polyester (PES) resin-reinforced composites have been prepared for ...

  4. Spin energy levels in axial symmetry: spin 4

    Energy Technology Data Exchange (ETDEWEB)

    de Biasi, R S; Portella, P D [Instituto Militar de Engenharia, Rio de Janeiro (Brazil). Secao de Engenharia e Ciencia dos Materiais

    1979-01-01

    The spin energy levels in axial symmetry are presented, in graphical and tabular form, for a spin 4. The levels are calculated for five different angles between the applied field and the symmetry axis 0/sup 0/, 30/sup 0/, 45/sup 0/, 60 and 90/sup 0/.

  5. Retinal thickness measurement and evaluation of natural history of the diabetic macular edema through optical coherence tomography Medida da espessura retiniana e avaliação da história natural do edema macular diabético pela tomografia de coerência óptica

    Directory of Open Access Journals (Sweden)

    Rosana Zacarias Hannouche

    2009-08-01

    influence on the center point thickness data, whereas values of visual acuity were significantly correlated with it. CONCLUSION: This study presents the optical coherence tomography applicability in the detection and semiologic evaluation of diabetic macular edema in patients with visual acuity 20/40 or greater, during one year, showing the retinal thickening in the early stages of diabetic retinopathy. Further, it evidenciated the correlation between the increase in foveal thickness and the reduction in visual acuity. Levels of hemoglobin A1c did not influence the center point thickness data. An early detection of clinically significant macular edema leads us to a redefinition of the real meaning of incipient retinopathy and can prevent further significant reduction of vision.OBJETIVOS: 1 Diagnosticar a presença de edema macular diabético em pacientes com retinopatia diabética e acuidade visual igual ou melhor que 20/40, pela realização do exame de tomografia de coerência óptica, medindo a espessura foveal central, ao longo de um ano. 2 Avaliar a história natural do edema, ao longo de um ano, associando a espessura foveal central com a hemoglobina glicosilada (HbA1c e alterações na acuidade visual. 3 Correlacionar os resultados obtidos com o grupo controle. MÉTODOS: Estudo prospectivo de uma amostra de 30 pacientes, com edema macular diabético e acuidade visual melhor ou igual a 20/40. O estudo contou com 30 olhos como grupo controle. Foram feitas medidas da melhor acuidade visual corrigida, dosagem de hemoglobina glicosilada, biomicroscopia com lente de 78 dioptrias, angiofluoresceinografia e tomografia de coerência óptica. Determinou-se, pelo propósito do estudo, a espessura foveal central como principal variável. Além da estatística descritiva, utilizaram-se testes para análise dos resultados: foi testada a homogeneidade de cada variável pelos testes t-Student, Qui-Quadrado e teste de Tukey; para correlacionar variáveis utilizou-se a análise de

  6. Acute neck pain caused by arthritis of atlanto-axial joint

    International Nuclear Information System (INIS)

    Kobayashi, Takashi; Ishikawa, Yoshinori; Abe, Eiji; Konno, Norikazu; Noguchi, Hideaki

    2009-01-01

    We reviewed 27 cases in which the patient complained of acute neck pain. We had performed arthrocentesis of the atlanto-axial joint in every case. An aspirate was obtained in 16 of the cases, and calcium pryophosphate dihydrate (CPPD) crystals were demonstrated in 10 of them. The patients' scores on the visual analogue scale decreased 30 minutes after aspiration of the crystals (p<0.001). CT demonstrated calcification of the transverse ligament in 22 cases, calcification anterior to the body of C2 in 2 cases, and no calcification in 3 cases. The results in these patients suggest that acute neck pain in some elderly patients is related to arthritis of the atlanto-axial joint. (author)

  7. A case of supratentorial intra-axial ependymoma showing exophytic growth

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Seung Woo; Kim, Eung Yeop [Yonsei University College of Medicine, Seoul (Korea, Republic of)

    2007-11-15

    A 17-year-old female had headache for several weeks and she developed an episode of seizure one day prior to admission. She underwent both CT and MRI, which both revealed a large tumor with cystic and solid portions at the right frontoparietal convexity. During operation, a well-defined tumor was found to have a stalk connecting the tumor itself with the brain parenchyma, proving that it was growing exophytically and expanding into the subarachnoid space. Histopathological examination revealed an anaplastic ependymoma with high cellularity. We report here on this case of an unusual supratentorial ependymoma with exophytic growth, and this can be mistaken as another exophytic growing intra-axial tumor or even as an extra-axial tumor.

  8. Tuned dynamics stabilizes an idealized regenerative axial-torsional model of rotary drilling

    Science.gov (United States)

    Gupta, Sunit K.; Wahi, Pankaj

    2018-01-01

    We present an exact stability analysis of a dynamical system idealizing rotary drilling. This system comprises lumped parameter axial-torsional modes of the drill-string coupled via the cutting forces and torques. The kinematics of cutting is modeled through a functional description of the cut surface which evolves as per a partial differential equation (PDE). Linearization of this model is straightforward as opposed to the traditional state-dependent delay (SDDE) model and both the approaches result in the same characteristic equation. A systematic study on the key system parameters influencing the stability characteristics reveals that torsional damping is very critical and stable drilling is, in general, not possible in its absence. The stable regime increases as the natural frequency of the axial mode approaches that of the torsional mode and a 1:1 internal resonance leads to a significant improvement in the system stability. Hence, from a practical point of view, a drill-string with 1:1 internal resonance is desirable to avoid vibrations during rotary drilling. For the non-resonant case, axial damping reduces the stable range of operating parameters while for the resonant case, an optimum value of axial damping (equal to the torsional damping) results in the largest stable regime. Interestingly, the resonant (tuned) system has a significant parameter regime corresponding to stable operation even in the absence of damping.

  9. Características da demanda por tomografia computadorizada crânio-encefálica motivos e custos dos exames

    Directory of Open Access Journals (Sweden)

    Ana Tereza Ramos de Oliveira

    1992-03-01

    Full Text Available Foram levantadas as 2860 tomografias computadorizadas crânio-encefálicas (TCCE feitas em um dos três serviços da cidade do Salvador, Brasil, sendo: caracterizados o perfil do usuário e a procedência da demanda; analisados os motivos dos exames e os custos com TCCE normais e anormais. Foram constatadas frequências altas de exames normais: (a para o sexo feminino (66,0% e até os 54 anos (73,0%, neste sexo (variação de exames normais entre 65 e 80%; (b para o sexo masculino nos grupos <15, 25-34 e 35-44 anos (64,7%; (c para solicitações efetuadas pelos convênios (65,3%; (d pelos seguintes motivos, para homens e mulheres respectivamente: cefaléias (81,3 e 87,5%; desmaios/tonturas (79,3 e 78,6%; convulsões (67,3 e 70%; retardo do desenvolvimento psicomotor (72,0 e 67,7%; «distúrbios endócrinos» (75,0% em cada sexo. Proporções altas de exames anormais foram observadas pelos seguintes motivos e para homens e mulheres, respectivamente: síndrome demencial (91,7 e 83,3%; acidentes vasculares encefálicos (85,1 e 73,7%; doenças infecciosas (76,5 e 78,6%; suspeitas de tumor (65,8 e 55,4%; e traumatismo crâ-nioencefálico, 63,6% no sexo masculino. No total, os custos com as TCC normais corresponderam a US$ 565,255 e com as anormais, US$ 381,247; para os convênios, os custos com TCC normais foram 2,2 vezes superiores ao INAMPS e 2,8 vezes superiores àqueles da medicina privada.

  10. Renormalization of the axial-vector current in QCD

    International Nuclear Information System (INIS)

    Chiu, C.B.; Pasupathy, J.; Wilson, S.L.

    1985-01-01

    Following the method of Ioffe and Smilga, the propagation of the baryon current in an external constant axial-vector field is considered. The close similarity of the operator-product expansion with and without an external field is shown to arise from the chiral invariance of gauge interactions in perturbation theory. Several sum rules corresponding to various invariants both for the nucleon and the hyperons are derived. The analysis of the sum rules is carried out by two independent methods, one called the ratio method and the other called the continuum method, paying special attention to the nondiagonal transitions induced by the external field between the ground state and excited states. Up to operators of dimension six, two new external-field-induced vacuum expectation values enter the calculations. Previous work determining these expectation values from PCAC (partial conservation of axial-vector current) are utilized. Our determination from the sum rules of the nucleon axial-vector renormalization constant G/sub A/, as well as the Cabibbo coupling constants in the SU 3 -symmetric limit (m/sub s/ = 0), is in reasonable accord with the experimental values. Uncertainties in the analysis are pointed out. The case of broken flavor SU 3 symmetry is also considered. While in the ratio method, the results are stable for variation of the fiducial interval of the Borel mass parameter over which the left-hand side and the right-hand side of the sum rules are matched, in the continuum method the results are less stable. Another set of sum rules determines the value of the linear combination 7F-5D to be roughly-equal0, or D/(F+D)roughly-equal(7/12). .AE

  11. The Modelling of Axially Translating Flexible Beams

    Science.gov (United States)

    Theodore, R. J.; Arakeri, J. H.; Ghosal, A.

    1996-04-01

    The axially translating flexible beam with a prismatic joint can be modelled by using the Euler-Bernoulli beam equation together with the convective terms. In general, the method of separation of variables cannot be applied to solve this partial differential equation. In this paper, a non-dimensional form of the Euler Bernoulli beam equation is presented, obtained by using the concept of group velocity, and also the conditions under which separation of variables and assumed modes method can be used. The use of clamped-mass boundary conditions leads to a time-dependent frequency equation for the translating flexible beam. A novel method is presented for solving this time dependent frequency equation by using a differential form of the frequency equation. The assume mode/Lagrangian formulation of dynamics is employed to derive closed form equations of motion. It is shown by using Lyapunov's first method that the dynamic responses of flexural modal variables become unstable during retraction of the flexible beam, which the dynamic response during extension of the beam is stable. Numerical simulation results are presented for the uniform axial motion induced transverse vibration for a typical flexible beam.

  12. The geometrical theory of diffraction for axially symmetric reflectors

    DEFF Research Database (Denmark)

    Rusch, W.; Sørensen, O.

    1975-01-01

    The geometrical theory of diffraction (GTD) (cf. [1], for example) may be applied advantageously to many axially symmetric reflector antenna geometries. The material in this communication presents analytical, computational, and experimental results for commonly encountered reflector geometries...

  13. Diameter and axial position measurement of micrometric particles by in-line digital holography using wavelet transform

    International Nuclear Information System (INIS)

    Torres, Y M; Amezquita, R; Monroy, F

    2011-01-01

    In this paper, the size and axial position of micrometric particles is obtained for an in-line Fraunhofer holography setup. The hologram reconstruction was realized using the wavelet transform. By digital image processing tools, the size distribution histogram for the particles in the sample was obtained. The contrast measurement in the amplitude reconstruction presents a peak when the axial coordinate and the register distance are equal. This fact lets the axial position in the sample be determined.

  14. Valor de la resonancia magnética de imágenes en pacientes con enfermedad cerebrovascular isquémica Evaluation of the magnetic resonance imaging in patient with ischemic cerebrovascular disease

    Directory of Open Access Journals (Sweden)

    Laura María Pons Porrata

    2009-04-01

    Full Text Available La resonancia magnética de imágenes permite investigar aspectos morfológicos y funcionales del cerebro, lo cual es sumamente útil para diagnosticar enfermedades neurológicas, incluidas las cerebrovasculares y, por supuesto, la isquemia cerebral en las primeras horas de ocurrida, de modo que facilita seguir la evolución del ictus, reducir la zona de necrosis y garantizar una mejor calidad de vida de los pacientes. A diferencia de la tomografía y la angiografía no utiliza radiaciones ionizantes. En este artículo se concluye, entre otras inferencias, que su elevada sensibilidad supera el número de confirmaciones obtenidas a través de la tomografía axial computarizada.Magnetic resonance imaging allows to investigate morphological and functional aspects of the brain, something extremely useful to diagnose neurological diseases, including the cerebrovascular diseases and, of course, the cerebral ischemia in the first hours of its ocurrence, so it facilitates to follow the clinical course of ictus, to reduce the necrosis area and to guarantee a better life quality of patients. Contrary to tomography and angiography it doesn't use ionizing radiations. In this article it is concluded, among other things, that its high sensibility overcomes the number of confirmations obtained through computarized axial tomography.

  15. Influence of energy and axial momentum spreads on the cyclotron maser instability in intense hollow electron beams

    International Nuclear Information System (INIS)

    Uhm, H.S.; Davidson, R.C.

    1979-01-01

    The influence of energy and axial momentum spreads on the cyclotron maser instability in an intense hollow electron beam propagating parallel to a uniform axial magnetic field B 0 e/sub z/ is investigated. The stability analysis is carried out within the framework of the linearized Vlasov--Maxwell equations. It is assumed that ν/gamma-circumflexvery-much-less-than1, where ν is Budker's parameter and gamma-circumflexmc 2 is the characteristic electron energy. Stability properties are investigated for the choice of electron distribution function in which all electrons have a step-function distribution in energy (H=γmc 2 ) and a step-function distribution in axial momentum (p/sub z/). The instability growth rate is calculated including the important stabilizing influence of energy spread (epsilon=Δγ) and axial momentum spread (Δ=Δp/sub z/). It is shown that a modest energy spread (epsilonapprox. = a few percent) is sufficient to stabilize perturbations with high magnetic harmonic number (s> or =2). Moreover, a relatively small axial momentum spread (Δ/mcapprox. =0.1) can easily stabilize perturbations with axial wavenumber satisfying vertical-barkc/ω/sub c/vertical-bar> or approx. =0.2, for typical beam parameters of experimental interest

  16. Dynamic interaction between rotor and axially-magnetized passive magnetic bearing considering magnetic eccentricity

    DEFF Research Database (Denmark)

    Enemark, Søren; Santos, Ilmar

    2014-01-01

    with a multibody system composed of rigid rotor and flexible foundation. The magnetic eccentricities of the shaft magnets are modelled using the distances (amplitudes) and directions (phase angles) between the shaft axis and the centre of the magnetic fields generated. A perturbation method, i.e. harmonic......-linear stiffness. In this investigation passive magnetic bearings using axially- aligned neodymium cylinder magnets are investigated. The cylinder magnets are axially magnetised for rotor as well as bearings. Compared to bearings with radial magnetisation, the magnetic stiffness of axially-aligned bearings...... is considerably lower, nevertheless they allow for asymmetric stiffness mounting, and it could be beneficial for rotor stabilization. A theoretical model is proposed to describe the non-linear rotor-bearing dynamics. It takes into account non-linear behaviour of the magnetic forces and their interaction...

  17. Special examinations in neuroradiology diagnostic of the neurological complications in atlanto axial dislocations

    International Nuclear Information System (INIS)

    Mihale, J.

    1998-01-01

    We report about contribution myelography, CT myelography, vertebral angiography and angio-cinematography, CT and MRI in diagnostic of the neurological complications of the ventral atlanto axial dislocation in 126 patients with progressive polyarthritis and ankylosing spondylarthritis. On the myelogram, and CT myelogram we visualized narrowing of the spinal channel in ventral atlanto axial dislocation. In patients with unreponibile dislocation up to the stop contrast medium between C1 and C2 vertebrae. With vertebral angiography and angio-cinematography we visualized changes in course of the arteries until with stop of the contrast medium in ante-flexion of the head in patients with unreponibile atlanto axial dislocation. On the MRI studies we visualized pathological changes in the front and back of the atlanto odontoidal joints and compression of the spinal cord. (author)

  18. Investigation of flow in axial turbine stage without shroud-seal

    Directory of Open Access Journals (Sweden)

    Straka Petr

    2015-01-01

    Full Text Available This article deals with investigation of the influence of the radial gaps on the efficiency of the axial turbine stage. The investigation was carried out for the axial stage of the low-power turbine with the drum-type rotor without the shroud. In this configuration the flow through the radial gap under the hub-end of the stator blades and above the tip-end of the rotor blades leads to generation of the strong secondary flows, which decrease the efficiency of the stage. This problem was studied by experiment as well as by numerical modelling. The experiment was performed on the test rig equipped with the water brake dynamometer, torque meter and rotatable stator together with the linear probe manipulator. Numerical modelling was carried out for both the steady flow using the ”mixing plane” interface and the unsteady flow using the ”sliding mesh” interface between the stator and rotor wheels. The influence of the radial gap was studied in two configuration a positive and b negative overlapping of the tip-ends of the rotor blades. The efficiency of the axial stage in dependence on the expansion ratio, velocity ratio and the configuration as well as the details of the flow fields are presented in this paper.

  19. The New Performance Calculation Method of Fouled Axial Flow Compressor

    Directory of Open Access Journals (Sweden)

    Huadong Yang

    2014-01-01

    Full Text Available Fouling is the most important performance degradation factor, so it is necessary to accurately predict the effect of fouling on engine performance. In the previous research, it is very difficult to accurately model the fouled axial flow compressor. This paper develops a new performance calculation method of fouled multistage axial flow compressor based on experiment result and operating data. For multistage compressor, the whole compressor is decomposed into two sections. The first section includes the first 50% stages which reflect the fouling level, and the second section includes the last 50% stages which are viewed as the clean stage because of less deposits. In this model, the performance of the first section is obtained by combining scaling law method and linear progression model with traditional stage stacking method; simultaneously ambient conditions and engine configurations are considered. On the other hand, the performance of the second section is calculated by averaged infinitesimal stage method which is based on Reynolds’ law of similarity. Finally, the model is successfully applied to predict the 8-stage axial flow compressor and 16-stage LM2500-30 compressor. The change of thermodynamic parameters such as pressure ratio, efficiency with the operating time, and stage number is analyzed in detail.

  20. Diagnostic potential of virtual bronchoscopy: advantages in comparison with axial CT slices, MPR and mIP?

    International Nuclear Information System (INIS)

    Rapp-Bernhardt, U.; Doehring, W.; Bernhardt, T.M.; Welte, T.; Kropf, S.

    2000-01-01

    The aim of this study was to evaluate the diagnostic potential of virtual endoscopy (VE) and to compare it with axial CT slices, multiplanar reconstructions (MPR), minimal intensity projections (mIP), and bronchoscopy in patients diagnosed with bronchogenic carcinoma. Thirty patients underwent a spiral CT. Axial CT images were transferred to an Onyx workstation (Silicon Graphics, Sun Microsystems, Mountain View, Calif.) for performing virtual endoscopy. Accuracy for this procedure was tested by three radiologists on a monitor in comparison with axial CT slices, MPR, mIP, and bronchoscopy concerning the localization and degree of stenoses. Endoluminal tumors were identified by virtual bronchoscopy with no statistically significant difference of localization or grading of stenosis in comparison with bronchoscopy, axial CT slices, MPR and mIP. Axial CT slices, MPR, and mIP showed poorer results with over- or underestimation of stenoses compared with VE and bronchoscopy. Passing of stenoses was only possible with VE in 5 patients. Virtual endoscopy is a non-invasive method for identification of endoluminal tumors and is comparable to real bronchoscopy. (orig.)