RESUMEN
This study focuses on a typical Brazilian household through the lens of sustainable development, regarding energy demand and GHG emissions. The analysis encompasses both the direct and indirect energy, exergy consumption, and GHG emissions (quantified by life cycle assessment) associated with the usual routine of a household. The household is modeled as a thermodynamic system to evaluate inputs (food, electricity, fuels for transportation) and outputs (solid and liquid residues). The hypothesis is that each input and output contains CO2,eq emissions and exergy derived from its physical-chemical characteristics or production chains. Each household appliance is modeled and tested as a function of external parameters. The contribution of several industries was obtained to the total GHG emissions and exergy flows entering and exiting the household (e.g., fuels for transportation, food, gas, electricity, wastewater treatment, solid waste). It was verified that urban transportation was the flow with the highest GHG and exergy intensity, ranging between 1.49 and 7.53 kgCO2,eq/day and achieving 94.7 MJ/day, almost five times higher than the calculated exergy demand due to electricity. The second largest flow in GHG emissions was food due to the characteristics of the production chains, ranging from 1.6 to 4.75 kgCO2,eq/day, depending on the adopted diet. On the other hand, the electricity presented low GHG emissions due to the main energy sources used to generate electricity, only 0.52 kgCO2,eq/day. Moreover, the chemical exergy of the solid waste was 9.7 MJ/day, and is not irrelevant compared to the other flows, representing an interesting improvement opportunity as it is entirely wasted in the baseline scenario.
RESUMEN
This article aims to describe the evolution of techniques that have enabled the proper application of the Laws of Thermodynamics for physical activity and athletes. The objective is to propose performance indicators to help add information to the current indices used in medicine and sports, such as the lactate threshold and maximum oxygen consumption. A number of analyses of the results obtained by the group were carried out for this purpose. Moreover, a discussion regarding which techniques would provide a better response to the measurements was analyzed. Some examples are the substitution of the treadmill running test with the stationary bicycle (known performed work), and a literature search in order to measure internal temperature more accurately. Level of Evidence V; Expert opinion.
Este artigo descreve a evolução de técnicas que possibilitaram a aplicação adequada das Leis da Termodinâmica às atividades físicas e aos atletas. O objetivo é propor indicadores de desempenho que ajudem a acrescentar informações aos índices atuais usados em medicina e nos esportes, como o limiar de lactato e o consumo máximo de oxigênio. Diversas análises dos resultados obtidos pelo grupo foram realizadas com essa finalidade. Além disso, procedeu-se à análise da discussão sobre quais técnicas proporcionariam resposta melhor às medições. Alguns exemplos são a substituição do teste de corrida em esteira pela bicicleta ergométrica (que sabidamente, pode ser usada para o trabalho), e a pesquisa da literatura para medir a temperatura interna com maior precisão. Nível de Evidência V; Opinião de especialista.
Este artículo describe la evolución de técnicas que posibilitaron la aplicación adecuada de las Leyes de la Termodinámica a las actividades físicas y a los atletas. El objetivo es proponer indicadores de desempeño que ayuden a acrecentar informaciones a los índices actuales usados en medicina y en los deportes, como el umbral de lactato y el consumo máximo de oxígeno. Fueron realizados diversos análisis de los resultados obtenidos por el grupo con esa finalidad. Además, se procedió al análisis de la discusión sobre qué técnicas proporcionarían respuesta mejor a las mediciones. Algunos ejemplos son la sustitución del test de carrera en cinta por la bicicleta ergométrica (que sabidamente, puede ser usada para el trabajo), y la investigación de la literatura para medir la temperatura interna con mayor precisión. Nivel de Evidencia V; Opinión de especialista.