Design of supersonic Coanda jet nozzles

The thrust vectoring of supersonic Coanda jets was improved by designing a nozzle to skew the initial jet velocity profile. A new nozzle design procedure, based on the method of characteristics, was developed to design a nozzle which produces a specified exit velocity profile. The thrust vectoring of a simple convergent nozzle, a convergent-divergent nozzle, and a nozzle which produces a skewed velocity profile matched to the curvature of the Coanda surface were expermentially compared over a range of pressure ratios from 1.5 to 3.5. Elimination of the expansion shocks with the C-D nozzle is shown to greatly improve the thrust vectoring; elimination of turning shocks with the skewed profile nozzle further improves the vectoring

Analysis of the reflex response time of the patellar stabilizer muscles in individuals with patellofemoral pain syndrome

OBJETIVO: Avaliar o tempo de resposta reflexa (TRR) dos músculos vasto medial oblíquo (VMO), vasto lateral oblíquo (VLO) e vasto lateral longo (VLL) em indivíduos clinicamente saudáveis e portadores de síndrome da dor patelofemural (SDPF). MÉTODOS: Foram avaliadas 12 mulheres clinicamente saudáveis e 12 mulheres com SDPF. Os registros eletromiográficos foram obtidos por eletrodos ativos simples conectados a um eletromiógrafo, acionados por um sensor externo fixado sobre a porção média do ligamento da patela a partir de sua percussão. A análise do TRR foi realizada por meio da medida do tempo zero ao pico da resposta elétrica dos músculos VMO, VLO e VLL, em segundos, para ambos os grupos. A análise estatística empregada foi o teste de análise de variância (ANOVA, p< 0,05) e teste Tukey post hoc (p< 0,05) para comparação entre os músculos, e o teste t de Student (p< 0,05) para a comparação entre os grupos. RESULTADOS: Ambos os grupos apresentaram um TRR menor para o músculo VMO, quando comparado aos músculos VLO e VLL; entretanto, não se observou diferença significativa entre os músculos VLO e VLL. Na comparação do TRR entre os grupos, não se observou diferença significativa. CONCLUSÕES: De acordo com esses resultados, pode-se sugerir que o TRR das porções do músculo quadríceps não diferencia indivíduos com SDFP dos indivíduos clinicamente saudáveis, sendo que o VMO apresenta um TRR menor em relação ao VLO e VLL para ambos os grupos.OBJECTIVE: To investigate the reflex response time (RRT) of the vastus medialis obliquus (VMO), vastus lateralis obliquus (VLO) and vastus lateralis longus (VLL) muscles in clinically healthy individuals and subjects with patellofemoral pain syndrome (PPS). METHODS: Twelve clinically health women and twelve women with PPS were evaluated. Electromyography (EMG) records were obtained using active electrodes connected to an electromyograph that was activated by an external sensor attached to the medial portion of the patella ligament, by means of percussion. The RRT was analyzed by measuring the time, in seconds, between zero and peak electrical response of the VMO, VLO and VLL muscles, for both groups. The statistical analysis consisted of analysis of variance (ANOVA, p< 0.05) and the Tukey post-hoc test (p< 0.05) to compare the response between muscles, and Student's t test (p< 0.05) to compare the response between groups. RESULTS: Both groups presented lower RRT for the VMO muscle than for the VLO and VLL muscles. However, no significant difference was seen between the VLO and VLL muscles. There was no significant difference in RRT between the groups. CONCLUSIONS: According to these results, it can be suggested that the RRTs in the different portions of the quadriceps muscle do not distinguish between subjects with PPS and clinically healthy individuals. The RRT for the VMO muscle was lower than the RRT for the VLO and VLL muscles, for both groups

Análise da postura cranio-cervical em pacientes com disfunção temporomandibular

OBJECTIVE: To compare head positioning and cervical spine alignment between individuals with and without temporomandibular disorders (TMDs), by means of positional evaluation using photographs, radiographs and visual observation, and to investigate whether the type of TMD influences head posture and cervical spine positioning. METHODS: Ninety randomly chosen women were diagnosed using the research diagnostic criteria for TMDs (RDC/TMD) by a trained examiner and were divided into three groups: Group 1, with a diagnosis of myofascial dysfunction (group I of RDC axis I); Group 2, with mixed TMD (groups I, II and III of RDC axis I); and Control, without TMD. Following this, the participants were photographed in frontal and lateral views by a single examiner. To produce these photos, the following anatomical points were marked out on the skin: occipital protuberance, C4, C7, acromioclavicular joint and sternoclavicular joint. From these points, different angles were analyzed by means of the ALCimagem-2000 application. These same photos were then evaluated qualitatively (visual evaluation). Next, lateral teleradiography and radiography of the cervical spine was requested. The examiner was blind when analyzing the images. To compare the results, the chi-squared test and analysis of variance were used, with significance levels of 5%. RESULTS: Regardless of the method used, the results revealed that head and cervical spine posture did not differ between the groups with and without TMD, independent of the diagnostic group. CONCLUSION: The posture of individuals with myogenic or arthrogenous TMD does not differ from the posture of individuals without TMD. The presence of TMD does not influence the head and cervical spine posture.OBJETIVO: Comparar o posicionamento da cabeça e o alinhamento da coluna cervical em indivíduos com e sem DTM, por meio da avaliação postural por fotografias, radiografias e por observação visual e verificar se o tipo de DTM influencia na postura da cabeça e no posicionamento da coluna cervical. MÉTODOS: Noventa mulheres escolhidas aleatoriamente foram diagnosticadas por meio dos Critérios para Diagnóstico em Pesquisa para Disfunções Temporomandibulares (RDC/TMD) por um examinador treinado e divididas em três grupos: grupo 1, diagnóstico de disfunção miofascial (grupo I do eixo I do RDC); grupo 2, com DTM mista (grupo I, II e III do eixo I do RDC) e controle, sem DTM . Em seguida, foram fotografadas em vista anterior e em perfil por um único examinador. Para a realização dessas fotografias, foram demarcados sobre a pele os seguintes pontos anatômicos: protuberância occiptal, C4, C7, articulação acromioclavicular e esternoclavicular. A partir desses pontos, foram analisados diferentes ângulos por meio do aplicativo ALCimagem-2000. Essas mesmas fotos foram posteriormente avaliadas qualitativamente (avaliação visual). Em seguida, foi solicitada uma radiografia e uma telerradiografia em perfil. O examinador foi cego ao analisar as imagens. Para comparação dos resultados, foi utilizado o teste qui-quadrado e a análise de variância com nível de significância de 5%. RESULTADOS: Independentemente do método utilizado, os resultados revelaram que a postura da cabeça e da coluna cervical não diferem entre o grupo com DTM e sem DTM, independentemente do grupo diagnosticado. CONCLUSÃO: A postura do indivíduo com DTM miogênica ou artrogênica não é diferente do indivíduo sem DTM. A presença da DTM não influencia na postura da cabeça e da coluna cervical

CORRELATION BETWEEN ELECTROMYOGRAPHIC ACTIVITY AND STRENGTH OF THE FLEXOR MUSCLES OF THE WRIST

INTRODUCTION: In analysing the electromyographic (EMG) signal, researchers are often led to interpret variations of the signal as variation in strength of muscle contraction. However, the relationship between the force exerted and the electrical activity of a muscle are not well established. This is due to the considerable variation of data acquisition and processing techniques, the detection site of the muscles analysed, as well as the alterations in their length and the type of contraction. The object of this paper was to evaluate the correlation between electrical activity and muscular strength. METHODS AND PROCEDURES: The flexor muscles of the wrist of the non dominant member of 21 female volunteers (mean age = 21 years, sd = ± 1.5) with no history of skeletal muscle dysfuntion, were analysed. The EMG signal was captured by active surface electrode (DELSYS), over the belly of the muscle in the longitudinal sense of the fibres, having a gain of 10 Hz. The electrode was coupled to a 16 channel 12/36 electromyograph (AqDados - LYNX TECNOLOGIA ELETRÔNICA LTDA), which permitted a gain of 50 Hz. The system bandwidth was 10 to 500 Hz, with an overall gain of 1,000. The data acquisition rate was 1,000 Hz. In order to eliminate possible interferences, a ground electrode was coupled to the distal segment of the forearm. Muscular strength was measured by means of a load cell (model MM/50 kg, KRATOS), placed perpendicularly in the center of the palm surface of the hand. The electrode and the load cell were connected to a 16 channel signal acquisition system (AQDADOS 4.0, LYNIX). The temperature of the room was kept at 23ºC, ± 1. The EMG registers and the strength were collected simultaneously. Result were obtained from the average of three repetitions, shown in RMS and Kgf respectively. The data was collected with the hand fixed to a device which limited the wrist to 45º of flexion and 45º of extension, providing an isometric contraction. RESULTS AND DISCUSSION: The results demonstrated a positive correlation between electromyographic activity and strength of contraction (r = 0.76) in the 45º flexion position, whereas, for the 45º extension position, the correlation was not significant (r = 0.23), considering the sample analysed. The data suggest that there is a positive correlation between EMG and strength, depending on the position of the muscle analysed

Comparative analysis between visual and computerized photogrammetry postural assessment

OBJETIVOS: Comparar a concordância interobservador da avaliação postural visual e por fotogrametria e verificar se os resultados quantitativos da fotogrametria correspondem à detecção de simetrias e assimetrias pela avaliação postural visual qualitativa. MÉTODOS: Vinte e um voluntários (24±1,9 anos) foram inicialmente avaliados visualmente por três fisioterapeutas experientes que preencheram um protocolo de avaliação postural. Em seguida tiveram fotografados a face e o corpo todo nos planos frontal anterior, posterior e sagital. As fotos foram utilizadas para traçar ângulos a partir de marcadores fixados à pele, em vários pontos anatômicos, que são referências frequentes na avaliação postural tradicional. Essas fotografias foram analisadas por três examinadores diferentes da avaliação postural visual. A concordância de cada método de avaliação postural foi avaliada pelos Coeficientes de Cramer V ou de PHI, considerando-se um nível de significância de 5%. RESULTADOS: Foi encontrada uma concordância entre os examinadores que utilizaram a fotogrametria para todos os segmentos avaliados. Não apresentaram concordância os segmentos comissura labial (p=0,00), acrômio clavicular (p=0,01), esternoclavicular (p=0,00), espinhas ilíacas anterior e posterior (p=0,00 e p=0,01) e ângulo inferior da escápula (p=0,00), que foram analizados por meio da avaliação postural visual. A comparação entre a fotogrametria e a avaliação postural visual demonstrou que o grau de concordância entre os dois métodos de avaliação foi pouco significativo para alguns segmentos do membro inferior e pelve. CONCLUSÕES: Nessas condições experimentais, os dados da fotogrametria não podem ser correlacionados com os dados da avaliação postural visual. A avaliação postural visual apresentou dados menos concordantes do que a fotogrametria, devendo ser questionada sua utilização como gold-standart.OBJECTIVES: To compare the interobserver agreement between visual and photogrammetry postural assessment and to determine whether the quantitative photogrammetry results correspond to the symmetries and asymmetries detected through qualitative visual postural assessment. METHODS: Twenty-one volunteers (mean age 24±1.9 years) were visually evaluated by three experienced physical therapists, who completed a postural assessment form. The participants' face and whole body were then photographed in the anterior and posterior frontal and sagittal planes. The photographs were used to draw angles from markers fixed to the skin at various anatomical points that are frequent references in traditional postural assessment. These photographs were analyzed by three examiners (other than the ones who performed the visual assessment). The agreement in each postural assessment method was determined using Cramer's V or the Phi coefficient, with the significance level set at 5%. RESULTS: There was agreement between the examiners who used photogrammetry, for all segments analyzed. No agreement was found for the labial commissure (p=0.00), acromioclavicular joint (p=0.01), sternoclavicular joint (p=0.00), anterior and posterior iliac spines (p=0.00 and p=0.01) or inferior angle of the scapula (p=0.00) when assessed visually. The comparison between photogrammetry and visual postural assessment showed that the agreement level between the two assessment methods was poor for some segments of the lower limb and pelvis. CONCLUSIONS: Under these experimental conditions, the photogrammetry data were not correlated with the results from the visual postural assessment. The visual postural assessment produced data that were in less agreement than the photogrammetry data, and its use as a gold standard must be questioned

Incidência de fungos e desempenho de sementes de mamona.

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