ABSTRACT Motivation is a fundamental element for the practice of physical activity and the feeling of satisfaction with life. However, little is known about the role of such psychological variables in the lifestyle of Chilean university students. This study aimed to analyse the relationship between life satisfaction and the regulations of motivation and to compare such variables by physical activity level and sedentary behaviour of university students. The sample comprised 95 Chilean university students (63.2% female), with a mean age of 20.92 ± 1.98 years. The instruments were the IPAQ, the Satisfaction with Life Scale, and the Behavioural Regulation in Exercise Questionnaire. Descriptive measures, Pearson’s correlation coefficient, and Student’s t-tests were used to analyse the data. The results revealed positive and significant correlations between life satisfaction and intrinsic (r = 0,44), integrated (r = 0,38), and identified (r = 0,41) regulation. Students with high levels of physical activity scored higher for intrinsic, integrated, and identified regulation. Those who reported low sedentary behaviour showed higher identified regulation. Therefore, it is suggested that students’ motivational regulation may differ on some dimensions as those with higher levels of physical activity show more adaptive motivational regulation. Identified regulation also seems to play an important role in decreasing sedentary behaviour.

RESUMO A motivação é elemento fundamental para a prática de atividade física e o sentimento de satisfação com a vida. Contudo, pouco se sabe sobre o papel de tais variáveis psicológicas no estilo de vida de estudantes universitários chilenos. Este estudo teve como objetivos analisar as relações entre a satisfação com a vida e as regulações da motivação, e comparar tais variáveis em função do nível de atividade física e do comportamento sedentário de estudantes universitários. A amostra foi composta por 95 estudantes universitários chilenos (63,2% do gênero feminino), com idade média de 20,92 ± 1,98 anos. Os instrumentos avaliados foram o IPAQ, a Escala de Satisfação com a Vida e o Questionário de Regulação do Comportamento do Exercício. Medidas descritivas, coeficientes de correlação de Pearson e testes t de Student foram utilizados para analisar os dados. Os resultados revelaram correlações positivas e significativas entre satisfação com a vida e regulação intrínseca (r = 0,44), integrada (r = 0,38) e identificada (r = 0,41). Os estudantes com alto nível de atividade física obtiveram maiores pontuações para regulação intrínseca, integrada e identificada. Os indivíduos que reportaram menor comportamento sedentário possuíam maior regulação identificada. Desse modo, sugere-se que a regulação motivacional dos estudantes pode ser diferente em algumas dimensões, sendo que os indivíduos com maior nível de atividade física semanal demonstram regulações motivacionais mais adaptativas. A regulação identificada também parece desempenhar um papel importante para a redução do comportamento sedentário.

Resumen El sector financiero se caracteriza por una mayor presencia de hombres en los altos niveles directivos. Por esta razón, el presente trabajo tiene por objetivo determinar la influencia de la diversidad de género en el rendimiento financiero de estas instituciones. Se tomó una muestra de 31 cooperativas de ahorro y crédito del segmento I y también los 24 bancos privados del Ecuador. La diversidad de género se midió con tres indicadores: el porcentaje de mujeres, el índice de Blau y el índice de Shannon; la variable rendimiento fue medida con el ROA (rentabilidad sobre activos, por sus siglas en inglés), el ROE (rentabilidad financiera, por sus siglas en inglés) y el ratio de endeudamiento. Con un enfoque cuantitativo se relacionaron mediante modelos econométricos. Los resultados demuestran que las cooperativas tienen mayor diversidad de género que los bancos. La diversidad de género sí incide en el ROA, pero no en el ROE ni en el endeudamiento. Se requiere una mayor inclusión de la mujer en puestos directivos para una mejor diversidad.

Abstract The financial sector is characterized by a greater presence of men in senior management levels. For this reason, this paper aims to determine the influence of gender diversity on the financial performance of these institutions. This article analyzes a sample of 31 savings and credit cooperatives, as well as the 24 private banks in Ecuador. Gender diversity was measured with three indicators: the percentage of women, the Blau Index and the Shannon Index; the performance variable was measured with ROA and ROE and the debt ratio; and with a quantitative approach they were related through econometric models. The results show that cooperatives have greater gender diversity than banks. Gender diversity does affect ROA but not ROE or indebtedness. Greater inclusion of women in management positions is still required for better diversity.

Resumen Antecedentes: El consumo máximo de oxígeno es un indicador de la aptitud cardiorrespiratoria. Objetivo: El objetivo fue relacionar y comparar el V̇O2máx. como variable dependiente con la distancia estimada en la prueba de caminata de seis minutos (PC6M) como variable independiente en estudiantes universitarios, a la vez relacionar la distancia (dependiente) con variables demográficas y antropométricas (independientes). Metodología: Estudio cuantitativo, no experimental, transversal, y descriptivo-correlacional en el que participaron 110 estudiantes universitarios. Se midió antropometría básica y signos vitales, y se aplicó un método directo de V̇O2máx. (Test de Bruce) en cinta rodante, luego se estimó la distancia recorrida en PC6M con dos ecuaciones disponibles en la literatura. Diferencias entre hombres y mujeres en las pruebas aplicadas, correlación entre las distancias estimadas con el V̇O2máx. y variables antropométricas, y la prueba de ANOVA de medidas repetidas entre el V̇O2máx. y las distancias estimadas fueron utilizadas con el programa SPSS v.22 (p<0,05). Resultados: Se encontró correlaciones significativas entre el V̇O2máx. y distancias estimadas (p<0,05) en la muestra, en hombres y mujeres, y en algunos casos la distancia se correlacionó con el sexo, la edad, el peso, la estatura y el IMC (p<0,05). Sin embargo, hubo diferencias entre el V̇O2máx. y las distancias estimadas en la PC6M (p<0,001). Conclusiones: El método directo de V̇O2máx. es distinto de las ecuaciones de predicción de distancia, aunque tienen relación significativa.

Resumo Antecedentes: O consumo máximo de oxigênio é um indicador de aptidão cardiorrespiratória. Objetivo: O objetivo é relacionar e comparar a V̇O2 máx. como variável dependente com a distância estimada no teste de caminhada de seis minutos (TC6M) como uma variável independente em estudantes universitários, ao mesmo tempo, relacionar a distância (dependente) com variáveis demográficas e antropométricas (independente). Metodologia: Estudo quantitativo, não-experimental, transversal, descritivo-correlativo, no qual participaram 110 estudantes universitários. Antropometria básica e sinais vitais foram medidos, e um método direto de V̇O2 máx. (teste Bruce) foi aplicado na esteira, então a distância coberta em TC6M foi estimada com duas equações disponíveis na literatura. Diferenças entre homens e mulheres nos testes aplicados, correlação entre distâncias estimadas com V̇O2 máx. e variáveis antropométricas, e medidas repetidas teste ANOVA entre V̇O2 máx. e distâncias estimadas foram usadas com SPSS v.22 (p<0,05). Resultados: Foram encontradas correlações significativas entre V̇O2 máx. e distâncias estimadas (p<0,05) na amostra, em homens e mulheres, e em alguns casos a distância correlacionada com sexo, idade, peso, altura e IMC (p<0,05). Entretanto, houve diferenças entre V̇O2 máx. e distâncias estimadas em TC6M (p<0,001). Conclusões: O método direto de V̇O2 máx. é diferente das equações de previsão de distância, embora elas tenham relações significativas.

Abstract Background: Maximum oxygen consumption is an indicator of cardiorespiratory fitness. Aim: The purpose was, first, to relate and compare the V̇O2max as the dependent variable with the estimated distance in the six-minute walk test (SMWT) as the independent variable in university students and, secondly, to relate the distance (dependent) with demographic and anthropometric variables (independents). Methodology: A correlational, descriptive, and quantitative study with a non-experimental design was conducted on 110 university students. In the study, basic anthropometry and vital signs were measured. A direct method of V̇O2max (Bruce test) on a treadmill was applied. Then, the distance covered in the SMWT was evaluated with two equations available in the scientific literature. Differences between men and women were measured in the tests, the correlation between the distances estimated with V̇O2max and anthropometric variables, and repeated ANOVA measurement tests between V̇O2max and estimated distance were analyzed with the SPSS v.22 program (p<0.05). Results: Significant correlations were found between V̇O2max and estimated distances (p<0.05) in the total sample, men and women, and in some cases, the distance correlated with gender, age, weight, height, and BMI (p<0.05). However, there were differences between V̇O2max and distances estimated in the SMWT (p<0.001). Conclusions: The V̇O2max measurement method is different from the distance prediction equations, although they have a significant relationship.

ABSTRACT The study consists on the analysis of the relation between multibead welding and the electric current used on maintenance welding of an ASTM A131 grade A steel, by using the shield metal arc welding process and a design of experiment to identify the factors with most influence and if there is relation between the studied factors. Between the main results the heat affected zone of the samples reached the lower extremity of the plate thickness, however the hardness values for the affected extremities show a hardness value identical to the base metal. For use in a repair situation, the desired configuration would be the one presenting 2 weld beads as the CP4 (1,15kJ/mm and 1,37kJ/mm) for having the lowest microhardness values on the welded joint.

RESUMO O estudo consiste na análise da relação entre a soldagem multipasse e os valores de corrente elétrica utilizada na soldagem de manutenção de um aço ASTM A 131 grau A. Por meio do processo de soldagem de eletrodo revestido e um delineamento experimental buscou-se identificar quais os fatores mais influentes e se existe relação entre os fatores estudados. Entre os principais resultados, a zona afetada pelo calor das amostras atravessou a espessura da chapa, entretanto os valores de dureza para as extremidades afetadas demonstraram dureza idêntica ao metal de base. Para uso em uma situação de reparo, a configuração mais indicada seria a configuração com dois cordões de solda do CP4 (1,15 kJ/mm e 1,37 kJ/mm) por apresentar os menores valores de microdureza na junta soldada.

Resumo: Aços carbono são revestidos com Inconel 625® para atender os requisitos de projeto no Pré-Sal. Entretanto, isso gera microrregiões conhecidas como a zona não misturada (ZNM) e a zona parcialmente misturada (ZPM) sendo a sua formação relacionada a dissimilaridade entre o metal de base e o metal de adição. O objetivo desse artigo é analisar o efeito da diluição, da ZPM e da ZNM e do reaquecimento dessas microrregiões sobre a resistência ao arrancamento do aço 9%Ni revestido com a liga Inconel 625®. A ZNM tem direções cristalográficas similares a ZAC e é CCC igual a ZAC. A ZPM apresenta direções cristalográficas mais heterogêneas quando comparadas ao metal de solda e é CFC igual ao metal de solda. A nanodureza da ZPM é similar a ZAC e até 42,5% maior que o metal de solda. A nanodureza da ZNM é até 14,9% menor que ZPM, até 48,2% menor que o metal de solda e até 15% menor que a ZAC. Todos os corpos de prova tiveram a propagação da trinca no metal de solda e atendem o requisito de 140 MPa mínimo para a tensão de cisalhamento. A diluição apresenta uma correlação com a tensão de cisalhamento.

Abstract: Carbon steels are coated with Inconel 625® to comply the pre-salt project requirements. However, this generates micro-regions such as the unmixed zone (UMZ) and a partially mixed zone (PMZ), with the formation related to the dissimilarity between the base metal and the addition metal. The purpose of this article is the analyze of the effect of dilution, PMZ and UMZ and the reheating of these micro-regions on the pullout resistance of 9% Ni steel coated with the Inconel 625® alloy. The UMZ has similar crystallographic directions to the heat affected zone (HAZ) and is BCC equal to HAZ. The PMZ presents more heterogeneous crystallographic directions when compared to the weld metal and is FCC equal to the weld metal. The PMZ nano-hardness is similar to HAZ and up to 42.5% greater than the weld metal. UMZ's nano-hardness is up to 14.9% less than PMZ, up to 48.2% less than weld metal and up to 15% less than HAZ. All specimens had crack propagation in the weld metal and comply the requirement of 140 MPa minimum for shear stress. The dilution presents a correlation with the shear stress.

Abstract The six-minute walk test has been generally applied in people with pathologies and some studies have proposed models to predict maximum oxygen consumption. Our objective was to elaborate on an equation to predict the maximum oxygen consumption in the six-minute walking test for university students. A hundred and forty people participated in this study. The six-minute walking test was applied and after on a gradual exercise test was performed to determine the maximum oxygen consumption. A multivariate equation was developed and the analysis was done using the SPSS v.22 program (p < 0.05). The predictive model include gender, age, body mass index, distance performed and heart rate recovery (r = 0.83; p < 0.001). The equation fulfilled the assumptions of independence (p = 0.13), normality (p = 0.49) and homoscedasticity (p = 0.64). The Bland-Altman diagram indicated that there were no significant differences between the equation and the measurement of the maximum oxygen consumption (p = 0.89), with a confidence interval of 0.054 ml·kg·min-1 (95% CI [-0.72; 0.83]). The equation predicts the maximum oxygen consumption. It is suggested to evaluate university students considering biological and environmental differences between countries.

Resumen La prueba de caminata de seis minutos se ha aplicado generalmente en enfermos, y algunos estudios han propuesto modelos para predecir el consumo máximo de oxígeno. Nuestro objetivo fue elaborar una ecuación para predecir el consumo máximo de oxígeno en la prueba de caminata de seis minutos para estudiantes universitarios. Participaron 140 estudiantes. Se aplicó el test de marcha y después se realizó una prueba de ejercicio gradual para determinar el consumo máximo de oxígeno. Se elaboró una ecuación multivariada y el análisis se hizo con el programa SPSS v.22 (p < 0.05). El modelo predictivo incluyó el sexo, edad, índice de masa corporal, distancia recorrida y la frecuencia cardíaca de recuperación (r = 0.83; p < 0.001). La ecuación cumplió con los supuestos de independencia (p = 0.13), de normalidad (p = 0.49) y de homocedasticidad (p = 0.64). El diagrama de Bland-Altman indicó que no hubo diferencias significativas entre la ecuación y la medición del consumo máximo de oxígeno (p = 0.89), con un intervalo de confianza de 0.054 ml·kg·min-1 (95% IC [-0.72; 0.83]). La ecuación predice el consumo máximo de oxígeno. Se sugiere evaluar estudiantes universitarios considerando diferencias biológicas y ambientales entre países.

ABSTRACT: Colombia has three indigenous swine breeds (San Pedreño, Zungo and Casco de Mula), which are in the country approximately 500 years ago and are at risk of disappearing due to their reduced populations and the preferential use of improved foreign breeds in the production systems. In order to preserve the indigenous breeds, germplasm banks were created, whose populations have been maintained as closed nucleus. The objective of this study was to perform a pedigree analysis to characterize the genetic structure of the San Pedreño pig population of the germplasm bank. Genealogical information collected between 2008-2017 was analyzed to estimate the generational interval, pedigree completeness level, consanguinity and its evolution over time. The animals born between the years 2015 and 2017 were selected as the reference population to estimate the effective population size and parameters derived from the probability of gene origin. The average generational interval for the period studied was 2.13 years and the general consanguinity was 4.66%. For the reference population, the consanguinity was 6.73% and the effective population size was 25.31, while the effective number of founders and ancestors was 13 and 7 individuals, respectively, which has led to bottlenecks in the population. The results indicate that in order to maintain genetic variability and reduce inbreeding levels it is necessary to include unrelated individuals from other populations.

RESUMEN: Colombia cuenta con tres razas de cerdos criollos (San Pedreño, Zungo y Casco de Mula), los cuales se encuentran en el país hace 500 años aproximadamente y están en riesgo de desaparecer debido a sus reducidas poblaciones y al uso preferente de razas foráneas mejoradas en los sistemas de producción. Para conservar las razas criollas se crearon los bancos de germoplasma, cuyas poblaciones se han mantenido como núcleos cerrados. El objetivo del estudio fue realizar un análisis de pedigrí para caracterizar la estructura genética de la población de cerdos San Pedreño del banco de germoplasma. Información genealógica colectada entre 2008-2017 se analizó para estimar el intervalo generacional, nivel de integridad del pedigrí, consanguinidad y evolución a través del tiempo. Los animales nacidos entre 2015 y 2017 se seleccionaron como población de referencia para estimar el tamaño efectivo poblacional y parámetros derivados de la probabilidad del origen genético. El intervalo generacional promedio para el periodo estudiado fue de 2.13 años y la consanguinidad general de 4.66%. Para la población de referencia, la consanguinidad fue del 6.73% y el tamaño efectivo poblacional de 25.31, en tanto que el número efectivo de fundadores y ancestros fue de 13 y 7 individuos, respectivamente; lo que ha conllevado a cuellos de botella en la población. Los resultados indican que para mantener la variabilidad genética y reducir los niveles de consanguinidad es necesario incluir individuos no emparentados de otras poblaciones.

Abstract: The objective of present study was to predict the carcass characteristics of 28 discarded Pelibuey ewes (41.01 ± 8.43 kg) using ultrasonography. The ultrasonic measurements of fat thickness (FT), area, (LDA), depth (DLD) and width (WLD) of the Longissimus dorsi, between the 12th and 13th thoracic vertebra and between the 3rd and 4th lumbar vertebra, were performed 24 h before slaughter. At the slaughter, hot carcass, internal organs and internal fat were weighed. The carcasses were divided in two half, refrigerated (1 °C; 24 h) and the chilled carcass were weighed. Then were dissected and weighed in the main tissues. With the data it was calculated the correlation coefficients between the variables and their relationships were estimated using regression models. It was observed that the ultrasonic measurements of thoracic and lumbar backfat thickness had a positive r2 that ranged from 0.51 to 0.66 (P<0.001) for prediction of the carcass weights; and an r2 from 0.44 to 0.57 (P<0.001) to predict the carcass muscle quantity. It is possible to use the measurements of ultrasound as a tool for the evaluation of carcass characteristics in discarded Pelibuey ewes and it is possible to predict the carcass weights and edible tissues.

Resumen: El objetivo fue predecir mediante ultrasonografía las características de la canal de 28 ovejas Pelibuey (41.01 ± 8.43 kg) de desecho alimentadas en sistema intensivo, clínicamente sanas, no gestantes y no lactantes. Las mediciones ultrasónicas de espesor de grasa dorsal (EGD), área, (ALD), profundidad (PLD) y ancho (ALD) del músculo Longissimus dorsi, entre la 12.a y 13.a vertebra torácica y entre la 3.a y 4.a vértebra lumbar, se realizaron 24 h antes del sacrificio. Al sacrificio se pesó la canal caliente, así como los órganos internos y la grasa interna. Las canales se dividieron a la mitad, se refrigeraron (1°C; 24 h) y se pesaron en canal frío. Luego fueron diseccionadas y pesadas en sus principales componentes. Con los datos se calcularon los coeficientes de correlación entre variables y las relaciones se estimaron mediante modelos de regresión. Se observó que las mediciones ultrasónicas de grasa dorsal, torácica y lumbar tuvieron un r2 positiva de entre 0.51 y 0.66 (P<0.001) en la predicción de los pesos de la canal; y un r2 de entre 0.44 a 0.57 (P<0.001) para predecir el tejido muscular en la canal. Es posible utilizar las mediciones de ultrasonido como una herramienta para la evaluación de características de la canal de ovejas Pelibuey de desecho, y es posible predecir el peso de la canal y los tejidos comestibles.

Resumen La prueba de caminata de seis minutos (PC6M) consiste en recorrer la mayor distancia posible y se caracteriza por ser una prueba de fácil realización. El objetivo de esta revisión fue examinar la relación entre las variables de distancia recorrida, patologías cardíacas, pulmonares y el consumo de oxígeno de una prueba de criterio en cinta rodante y/o cicloergómetro, y las ecuaciones de predicción del VO2 en la PC6M de Maldonado e Ingle (2006), Vanhelst (2013) y Costa (2017) para personas con patologías. El manuscrito es una revisión bibliográfica que utilizó las bases de datos Scopus y WOS, con artículos en inglés, español y portugués entre 2000 y 2017. La distancia es la variable que más se midió y que más se asoció con el VO2, encontrándose correlaciones significativas con valores de 0.01 hasta 0.8, las patologías más relacionadas con el VO2 máx. fueron la hipertensión pulmonar, enfermedad pulmonar obstructiva, insuficiencia cardíaca, disfunción sistólica ventricular y accidente cerebro-vascular y el cicloergómetro fue el más utilizado en las pruebas de criterio de VO2 máx. Solo una ecuación fue elaborada para niños que eran obesos la que incluyó distancia e IMC (Vanhelst), otra ecuación fue para adultos con enfermedad cardíaca que además incluía el sexo (Costa), una en pacientes con disfunción sistólica ventricular que aparte incorporó la edad, volumen espiratorio y hemoglobina (Ingle) y otra fórmula fue para adultos con insuficiencia cardíaca que consideró la distancia (Maldonado). Se sugiere utilizar la ecuación más apropiada y elaborar modelos predictivos para personas con diversas características.

Resumo O teste de caminhada de seis minutos (TC6M) consiste em andar o mais longe possível e é caracterizado como um teste fácil. O objetivo desta revisão foi examinar a relação entre as variáveis distância percorrida, patologias cardíacas, pulmonares e o consumo de oxigênio de um teste de critério em esteira e/ou ciclo ergômetro, e as equações de predição do VO 2 no TC6M de Maldonado e Ingle (2006), Vanhelst (2013) e Costa (2017) para pessoas com patologias. O manuscrito é uma revisão bibliográfica que utilizou as bases de dados Scopus e WOS, com artigos em inglês, espanhol e português entre 2000 e 2017. A distância é a variável mais medida e mais associada ao VO 2, encontrando correlações significativas com valores de 0,01 a 0,8, as patologias mais relacionadas ao VO 2 max. foram a hipertensão pulmonar, doença pulmonar obstrutiva, insuficiência cardíaca, disfunção sistólica ventricular e acidente vascular encefálico e o ciclo ergômetro foi o mais utilizado nos testes do critério VO 2 max. Apenas uma equação foi desenvolvida para crianças obesas, que incluíram distância e IMC (Vanhelst), outra equação foi para adultos com doença cardíaca que também incluiu sexo (Coast), uma em pacientes com disfunção sistólica ventricular que incorporaram a idade, volume expiratório e hemoglobina (Ingle) e outra fórmula foi para adultos com insuficiência cardíaca que considerou a distância (Maldonado). Sugere-se utilizar a equação mais adequada e desenvolver modelos preditivos para pessoas com características diversas.

Abstract The six-minute walk test (SMWT) consists of walking as far as possible and is characterized by being an easy test to perform. This paper examines the relationship between the variables of distance traveled, cardiac and pulmonary pathologies, and the oxygen consumption of a criterion test on treadmill and/or cycle ergometer, and the prediction equations of VO2 in the SMWT of Maldonado and Ingle (2006), Vanhelst (2013) and Costa (2017) for people with pathologies. The paper is a bibliographic review that used the Scopus and WOS databases containing articles in English, Spanish and Portuguese, published between 2000 and 2017. Distance is the variable that was most measured, and it was most associated with VO2; correlations with values from 0.01 to 0.8 were found. The pathologies most related to VO2 max were pulmonary hypertension, obstructive pulmonary disease, and ventricular heart failure and stroke; and the cycle ergometer was the most commonly used in the VO2 max criterion tests. Only one equation was created for children who were obese; it included distance and BMI (Vanhelst). Another equation was generated for adults with heart disease that also included sex (Costa). Besides, one equation was for patients with ventricular systolic dysfunction that also incorporated age, volume expiratory and hemoglobin (Ingle); another one was created for adults with heart failure, and this formula considered the distance (Maldonado). It is suggested to use the most appropriate equation and create predictive models for people with different characteristics.

Resumen Se desarrolló un sistema de fijación externa monolateral para alargamiento de huesos más fácil de utilizar que los sistemas comerciales puesto que las prensas pueden ser ensambladas lateralmente en el riel a diferencia de los sistemas comerciales donde las prensas solo se pueden ensamblar desde los extremos. El sistema está formado por prensas, tornillos y riel. El riel está formado por dos barras circulares de fibra de carbono de ½” diámetro y 42 cm de longitud. Las prensas se pueden deslizar axialmente con respecto al riel para permitir distracción o se pueden fijar al riel usando una cuña y un tornillo. El prototipo fue evaluado mecánicamente bajo la norma ASTM F1541. La rigidez bajo carga axial, flexión Medio Lateral (ML), flexión Antero Posterior (AP), y flexo torsión fueron 117 N/mm, 46 N/mm, 8.7 N/mm, and 5.8 N-mm/° respectivamente, que están en el rango de rigidez de sistemas comerciales.

Abstract We developed a monolateral external fixation system for bone lengthening that is easier to assemble than commercial systems. In this system, the clamps can be laterally assembled to the rail in contrast to the commercial systems in which the clamps can only be assembled from the ends. The system is formed by clamps, screws, and a rail. The rail is composed of two carbon fiber circular rods of ½” diameter and 42 cm length. The clamps can slide with respect to the rail to allow bone distraction or may be fixed to the rail by using a wedge and a screw. The prototype was mechanically evaluated under the ASTM F1541 standard. The stiffness in axial loading, medio-lateral bending (ML), antero-posterior bending (AP), and flexo-torsional loading were 117 N/mm, 46 N/mm, 8.7 N/mm, and 5.8 N-mm/°, respectively, which are in the range of the stiffness of commercial systems.

Abstract Polymer matrix nanocomposites (NMP) have attracted a great interest mainly in the automotive, aerospace and medical industries since they have good mechanical properties, dimensional, thermal and chemical stability, as well as interesting electrical conductivity and cost reduction in the manufacturing process. However, welding of this class of materials presents serious challenges such as improving weldability of the joint and understanding the mechanisms responsible for coalescence. The objective of this work was to evaluate the coalescence of an NMP joint (comprising a PA6 matrix and with nanosilica of different percentages of silicon) using ultrasonic welding, as well as to perform an acoustic approach of the energy dissipation during the welding process. It is concluded that the NMP samples tend to show better coalescence as the percentage of nanosilica increases, up to a certain limit. On the other hand, the higher the content of nanoparticle the smaller the energy absorption.

Background: The six-minute walk test (SMWT) is an easy-to-use test that measures walking distance. Aim: To elaborate an equation to estimate the maximum oxygen consumption (VO2 max) using the results of the SMWT. Material and Methods: Forty men and 40 women aged 22.5 ± 2 years, underwent a SMWT to measure the total walked distance and the recovery heart rate (RhR) Also, VO2 max was estimated from the maximal workload achieved in a cyclo-ergometer using the Storer test. A multivariate regression analysis resulted in a prediction equation that was validated with distributional assumptions of normality, independence and homoscedasticity. The limits of concordance of the predictive model were checked with the Bland-Altman diagram. Results: Body mass index (BMI), sex, RhR and total walked distance explained VO2 max variance by 3.4, 73.1, 17.9 and 32.8%, respectively. The prediction equation achieved was VO2 max (ml.min−1) = −3672.585 + (966.472 × Sex [1: female, 2: male]) + (-18.492 X RhR [beats.minute−1]) + (9.191 X Distance [m]) + (87.707 × BMI). The R2 of the equation was 0.91 (p < 0.01). Conclusions: This equation predicts VO2 max in Chilean university students according to sex, BMI, cardiovascular response and performance in the SMWT.

Na soldagem de aço de baixo carbono podem ser empregados diversos consumíveis, como o arame tubular e o arame maciço. Este trabalho compara a taxa e a eficiência de deposição em função da corrente de soldagem, da distância do bico de contato à peça (DBCP) e do tipo de gás de proteção, comparando-se o ER70S-6 com o E71T-1C. As taxas de deposição foram medidas usando-se uma sequência de cordões de solda sobre chapa de aço. As frequências de destacamento das gotas foram medidas a partir de equipamento de aquisição de dados, baseando-se nas variações de tensão do arco. O diâmetro da gota foi calculado teoricamente com base na velocidade de alimentação do arame. Foi utilizado um programa para análise estatística dos resultados produzidos pelos experimentos. Os resultados mostraram que a taxa de deposição aumenta com o aumento da corrente e com o aumento da DBCP. Da mesma maneira, a variável mais importante para controlar a eficiência de deposição foi a natureza do consumível. O ER70S-6 apresentou uma maior eficiência de deposição que o arame tubular E71T-1C, como era esperado, uma vez que o arame tubular gera escória que não é contabilizada na massa do cordão depositado.

In welding of low carbon steel, various consumables types can be employed. Among them, flux cored wire and solid wire have great application potential and substitution toward other consumables like coated electrode. This paper compares the deposition rate, the deposition efficiency, the frequency of detachment of the drop of molten metal addition and the diameter of the droplet of molten filler metal, as a function of welding parameters such as welding current, contact tip to work distance (CTWD), and the type of shielding gas, comparing the ER70S-6 with the E71T-1C filler metal. Deposition rates were measured using a sequence of three welds performed in bead on plate on ASTM A36 steel plate. The frequencies of filler metal droplets were computed from data acquisition equipment, based on variations of arc voltage. The drop diameter was theoretically calculated based upon the wire feed speed. For data analysis, a program for statistical analysis of the results produced by the experiments was used, which allowed to determine up to the second order interactions between the studied parameters. The results of the experiments show that the deposition rate increases with increase in current and with increase in CTWD. Likewise, the most important factor to control the deposition efficiency was the type of the consumable. The ER70S-6 presented a higher deposition efficiency than the flux cored wire E71T-1C, as expected, since the flux cored wire produces slag, which is not take into account in the mass of deposited bead.