Athenea Engineering sciences journal

Analysis of Steam Economy in a Five-Effect Evaporation System for the Sugar Industry

Victor Alejandro Ascurra Valle — 2026-07-05

Steam economy is one of the main indicators of energy performance in multiple-effect evaporation systems used in the sugar industry. The objective of this study was to analyze the steam economy of a five-effect evaporation system using a quantitative approach and a quasi-experimental design based on real operational data. The influence of Brix degrees and the mass flow rate of clarified juice was evaluated through a multiple linear regression model, whose significance was verified by statistical analysis. The results showed that an increase in mass flow rate improves steam economy, whereas higher initial juice concentrations reduce its value. The obtained model showed high predictive capacity and made it possible to identify operational conditions that optimize steam utilization. It is concluded that mathematical modeling constitutes a useful tool for improving energy efficiency and supporting decision-making in the sugar industry.

Surface Urban Heat Islands in Coastal and Andean Ecuadorian Cities: Spatio-Temporal Analysis Using Landsat, Urban Vegetation, and Meteorological Reanalysis

Diana Katherine Campoverde Santos — 2026-07-06

Urban growth modifies the physical properties of the Earth's surface and may intensify thermal contrasts between built-up areas and peri-urban zones. This study analyzed the spatio-temporal dynamics of surface urban heat islands in coastal and Andean Ecuadorian cities using Landsat imagery, vegetation and built-up surface indicators, and meteorological reanalysis variables. Landsat products were processed in Google Earth Engine to estimate land surface temperature, calculate spectral indices, and compare urban and peri-urban areas. In addition, fifth-generation terrestrial reanalysis data from the European Centre for Medium-Range Weather Forecasts were incorporated, including air temperature, precipitation, and wind variables. The results show greater urban--peri-urban thermal contrast in Andean cities, whereas the coastal city exhibited higher temporal variability. Vegetation and built-up surface indicators showed differentiated relationships with land surface temperature, and meteorological variables allowed the observed thermal variability to be contextualized.

Analysis of Labor Productivity and Material Waste in Housing Construction

Royer Andree Araujo Mejia — 2026-07-10

La productividad de la mano de obra y el desperdicio de materiales son indicadores fundamentales para evaluar la eficiencia de los proyectos de construcción. El objetivo de este estudio fue evaluar la productividad laboral y el desperdicio de concreto, mortero y ladrillo en viviendas del sector norte de Celendín, Perú. Se desarrolló una investigación cuantitativa, aplicada, con diseño no experimental y alcance descriptivo-analítico. La productividad se evaluó mediante la técnica de carta balance y el desperdicio mediante mediciones directas en obra. Los resultados mostraron que el vaciado de columnas presentó el mayor porcentaje de trabajo productivo, mientras que el levantamiento de muros registró el mayor trabajo improductivo. Asimismo, los desperdicios de materiales permanecieron por debajo de los valores de referencia establecidos por CAPECO. Finalmente, se propuso un Índice de Eficiencia Operativa para integrar la evaluación del desempeño de las partidas constructivas.