Journal Of Exact Sciences and Technological Applications

Cellular Concrete Production Technologies: An Overview

Luísa Lopes — 2025-12-19

Cellular concrete is a widely used material in the construction industry and can be produced through different methods, which result in significant variations in its final properties. One of the most established techniques is the manufacturing of autoclaved blocks, subjected to a curing process under high pressure and temperature to enhance the mechanical strength and dimensional stability of the material. However, not all methods employ this type of curing. For instance, foamed blocks are produced with ambient curing by incorporating foaming agents that generate air bubbles directly within the mixture or through the addition of a pre-formed foam, providing the material with a lightweight and uniform cellular structure. Among the main production techniques for non-autoclaved cellular concrete are direct mixing and foam pre-formation. Additionally, this type of concrete may offer advantages such as accelerated carbonation reaction, contributing to a more efficient production process. Furthermore, cellular concrete can be manufactured using industrial or post-consumer waste by partially replacing conventional aggregates with paper ash, ceramics, and other materials, thus creating a sustainable product that reutilizes waste otherwise destined for disposal.

Teaching Chess as a Pedagogical Tool for Schoolchildren

Hernan Eduardo Seniw Gonçalves — 2025-12-19

Chess evolution is marked by historical events and great players, whose contribution have consolidated the game as one of the most complex and strategic in the world. The game requires the player to have a vision of the board as a whole, predicting moves and seeking the best combinations in order to achieve the goal, checkmate. Studies show that playing board games, including chess, provides benefits such as developing logical reasoning, increasing attention and long-term benefits in the educational process. The main objective of this project is to promote the practice of chess among children and adolescents from schools in the city of Cachoeira do Sul. Each semester, the project visits a specific school and the methodology applied is based on weekly meetings lasting two hours, divided in a theoretical stage and a practical stage. The theoretical covers topics such as the origin of chess, the particularities of the pieces and tactics. The practical consists of applying the concepts discussed, through games between participants, solving exercises and debates on strategic variants. In addition to activities at schools, weekly meetings are held on the campus of the Federal University of Santa Maria – Cachoeira do Sul, involving students and teachers and follow the same methodology used in schools. It is concluded that chess is a pedagogical tool with great potential, capable of promoting the cognitive and social development of students. The game develops interpersonal relationships, contributing for a more collaborative and inclusive school environment.

Influence of shakeout time on the microstructure and hardness of gray cast iron under industrial conditions

Renan Pfeifenberg — 2025-12-19

Gray cast iron is widely used due to its machinability and low cost, and its properties depend on the microstructure formed during cooling. This study evaluated the effect of shakeout time (2, 24, and 48 h) on the microstructure and hardness Brinell (HB) of parts produced in no-bake sand molds, using steel scrap as metallic charge and cast in a cupola furnace. Graphite morphology was classified according to ASTM A247, and hardness was measured as per ASTM E10. A microstructural evolution with shakeout time was observed: at 2 h, ferrite + pearlite matrix, Type A/E graphite, and 201.16 ± 2.63 HB; at 24 h, pearlitic matrix, Type A graphite, and 198.83 ± 2.92 HB; at 48 h, predominantly pearlitic matrix with residual ferrite, Type A/E graphite, and 214.33 ± 2.16 HB. The results indicate that shakeout time modulates the cooling rate, changing phase fractions and hardness with a non-monotonic response over the range studied. Therefore, shakeout time is a relevant process parameter for controlling the microstructure and properties of the gray cast irons.

UV-Vis analysis of the formation of iron-based nanoparticles

Arthur Batista Bromirsky — 2025-12-19

The present study investigated the temporal formation of iron nanoparticles (FeNPs) by means of UV-Vis spectroscopy, evaluating the behavior of both isolated and mixed reagents. The results validated the sensitivity and reliability of the method in monitoring nanoparticle formation and colloidal stability, with minimal spectral changes detected over four hours. Long-term monitoring is recommended to identify significant shifts in the wavelength of maximum absorption (Amax), which may be indicative of structural alterations or changes in their compositions.