BENCHMARKING OF TWO SYSTEMS FOR TRANSMISSION OF MOTION FOR A DOUBLE ACTION STIRLING ENGINE

In a four-piston Stirling engine, Siemens configuration, the displacement of the pistons is governed by the motion transmission element, which converts the reciprocating motion of pistons into rotary motion. This study aimed to evaluate the influence of the geometry of the transmission element in the mechanical efficiency of a Stirling engine. Analyses were performed using a mathematical computer simulation that uses the geometric and operating data of the engine to calculate the mechanical power and efficiency through a first order thermodynamic mathematical model, also known as the Schmidtmodel. First, an analysis was performed to evaluate the mechanical efficiency of the transmission element with a sinusoidal curve surface. Later, it was implemented in the transmission mechanism a segment based straight plans surface, and then the same analysis was performed with this new transmission element. The results showed that using the transmission element with segment based straight plans the engine showed a significant increase in efficiency. Moreover, one can observe an increase in the vibration of the system, making it necessary to develop an appropriate system for balancing

Identificação de méis adulterados utilizando FT-NIR e quimiometria.

O mel é um produto alimentício que tem sofrido constantemente processos de adulteração devido ao seu custo e sua disponibilidade limitada. Desta forma, o presente trabalho tem como objetivo analisar amostras de mel não adulteradas e adulteradas com glicose, melado de cana-de-açúcar e água, em diferentes proporções, 10%, 25%, 40% e 50% (m m-1). As amostras foram analisadas utilizando espectrometria na região do infravermelho próximo com transformada de Fourier (FT-NIR) e os resultados obtidos foram analisados utilizando a ferramenta quimiométrica de análise de componentes principais (PCA). A partir dos resultados obtidos, foi possível verificar a viabilidade da técnica NIR para verificação da adulteração de méis com água

Protein synthesis and degradation gene SNPs related to feed intake, feed efficiency, growth, and ultrasound carcass traits in Nellore cattle.

We looked for possible associations of SNPs in genes related to protein turnover, with growth, feed efficiency and carcass traits in feedlot Nellore cattle. Purebred Nellore bulls and steers (N = 290; 378 ± 42 kg body weight, 23 months ± 42 days old) were evaluated for daily feed intake, body weight gain (BWG), gross feed efficiency, feed conversion ratio, partial efficiency of growth, residual feed intake (RFI), ultrasound backfat, rump fat, and ribeye area

Effect of food supplementation on in vitro embryo production and growth performance in prepubertal Nelore heifers.

In vitro embryos production from prepubertal heifers can help contribute to breeding programs; however, strategies are necessary to increase their embryo production. The aim of this study was to investigate the effects of two nutritional plans on oocyte recovery, embryo production and growth performance of prepubertal Nelore heifers. Thirty-four Nelore heifers with age of 6.5&#8201;months were divided into two feeding treatments (NP1 and NP2). The NP1 diets served as the control and NP2 diets were formulated to contain an average of 1.22-fold more energy than NP1. After 3&#8201;months of supplementation, the animals underwent follicular aspiration (ovum pick-up, OPU) every 21&#8201;d for 3&#8201;months and embryos were produced in vitro. Wither height, chest depth, body weight and subcutaneous fat of animals were measured. The number of retrieved and viable oocytes per OPU were 1.49-fold and 1.42-fold greater in NP2 heifers (p&#8201;=&#8201;0.018 and p&#8201;=&#8201;0.049, respectively) than those in NP1 heifers. Heifers administered NP2 produced 29.7% blastocysts, a percentage higher than NP1 animals that produced 24.40% embryos (p&#8201;<&#8201;0.05). Consequently, females in the NP2 treatment showed improved body development. These results indicate a positive effect of a higher energy diet on assisted reproduction and body development in prepubertal heifers

Profiles of Parental Burnout Around the Globe: Similarities and Differences Across 36 Countries

Parental burnout (PB) is a pervasive phenomenon. Parenting is embedded in cultural values, and previous research has shown the role of individualism in PB. In this paper, we reanalyze previously collected data to identify profiles based on the four dimensions of PB, and explore whether these profiles vary across countries' levels of collectivistic-individualistic (COL-IND) values. Our sample comprised 16,885 individuals from 36 countries (73% women; 27% men), and we used a latent profile approach to uncover PB profiles. The findings showed five profiles: Fulfilled, Not in PB, Low risk of PB, High risk of PB and Burned out. The profiles pointed to climbing levels of PB in the total sample and in each of the three country groups (High COL/Low IND, Medium COL-IND, Low COL/High IND). Exploratory analyses revealed that distinct dimensions of PB had the most prominent roles in the climbing pattern, depending on the countries' levels of COL/IND. In particular, we found contrast to be a hallmark dimension and an indicator of severe burnout for individualistic countries. Contrary to our predictions, emotional distance and saturation did not allow a clear differentiation across collectivistic countries. Our findings support several research avenues regarding PB measurement and intervention

PHYSICAL ACTIVITY LEVEL DOES NOT INFLUENCE THE NEUROMUSCULAR FATIGUE IN ADULTS

Introduction: Fatigue during voluntary muscle contractions is a complex and multifactorial phenomenon associated with central changes and adaptations of the neuromuscular system. Objective: The purpose of this study was to evaluate the fatigue induced by intermittent successive extension of the knee between active and inactive university students. Method: Twenty healthy men (≥18 years), voluntarily participated in this study. To determine the maximum voluntary isometric contraction (MVIC) of the knee extensors muscle group, three sets of isometric contractions of knee extension were performed for five seconds with five minutes of rest between sets. The fatigue protocol consisted of 10 sets of 10 maximal concentric contractions of the extensor on the right knee, performed at 75% of MVIC with an interval of 45". Results: Significant reductions were observed (p<0.01), both in isometric strength (-34±4%) and the dynamic strength (-40 ± 3%). In addition, the slope of relationship strength x repetition was -0.79±0.07 Nm/repetitions and the magnitude of the effect reached -8.90. Conclusion: The protocol was useful to induce peripheral fatigue, although muscle strength is greater in the active group. In both isometric and dynamic action, muscle fatigue did not differ between groups