Esta pesquisa apresenta a descrição de um novo produto desenvolvido a partir de um material não convencional, oriundo da agricultura; os resíduos de casca de arroz. Procurar-se-á também apresentar o desenvolvimento e incorporação do mesmo material na construção civil, com potencial acústico, a partir de ensaios realizados e medições com aparelho calibrado denominado decibelímetro. Utilizou-se também o produto comercialmente conhecido pelas construtoras e incorporadoras de edificações, as lajotas de cerâmica pré-moldadas, usadas para confecção de pisos ou forros nos edifícios e casas. Esta pesquisa procurou apresentar uma nova opção de materiais alternativos para ambientes que exijam o cuidado com a acústica, bem como possibilitar a indústria da construção civil, novos estudos com materiais alternativos e que são muitas vezes rejeitados pela falta de informações ou desconhecimento pelos profissionais da área. A metodologia utilizada para o desenvolvimento dessa pesquisa caracterizou-se como bibliográfica, exploratória, descritiva, quali-quantitativa. Como resultados encontrados após as análises dos ensaios realizados, pode-se observar que a incorporação das cascas de arroz de forma aglomerada às lajotas cerâmica, possibilitaram reduções dos níveis de ruído na ordem de 8 dB (A), quando comparada a forma tradicional de construção nas edificações.

The construction market is very growing, leading to the emergence of new technologies and materials, and a growing need for sustainable products for the construction process, and the call for quality of life we present the description of a new option alternative materials for environments that require careful with the acoustics. The research covers the development and incorporation of new material in construction, with the potential acoustic, from tests and measurements with calibrated decibel meter called. We also used the ceramic tiles pre-molded, used for making floors or ceilings in buildings and homes. The methodology used for the development of this research was characterized as literature, exploratory, descriptive, qualitative and quantitative, alternative and affordable. How after the analysis results of the tests performed it can be seen that the incorporation of rice hulls of agglomerated to form ceramic tiles, possible reductions in noise levels on the order of 8 dB (A) than the traditional construction of the buildings, and then an excellent material. This research contributes to the construction so that presented a description of a new product developed from a conventional material, originating in agriculture, waste rice husk and its incorporation during the construction of buildings and home, with the potential acoustic observed from tests and measurements with calibrated decibel meter called.

We present a parametric analysis of gap variation between the lap brace and through brace of YT welded joints for rolled-steel circular hollow sections on plane steel structures. Our aim is to investigate the collapse behavior of YT-joints under lap brace axial compression. In particular, we focus on e/d0 ratios above 0.25 so bending moments can be taken into account during the design. We find that joint failure is primarily due to chord wall plastification (Mode A) and cross-sectional chord buckling (Mode F) in the region underneath the lap brace. Our joint design followed the Limit States Method, and our results were based on a comparative analysis of three different methods: an analytical solution derived from a set of international technical norms, an experimental analysis, and numerical modeling using Ansys as calibrated by our experimental results.

The effect of magnetic field on the crystallization of diamagnetic zinc sulfate was investigated in a series of controlled batch cooling experiments. Zinc sulfate solutions were exposed to magnetic fields of different intensities, up to a maximum of 0.7T. A clear influence of magnetic field on the following zinc sulfate crystallization parameters was found: an increase in saturation temperature, a decrease in metastable zone width, and an increase in growth rate and average crystal size. These effects were observed for the diamagnetic zinc sulfate, but not in similar, previously reported experiments for paramagnetic copper sulfate.

Devido ao crescente aumento do uso de aeradores artificiais em sistema de cultivo de peixes e à carência de estudos nesta área, este trabalho avaliou a influência de um aerador tipo "propeller diffuser" (AR 120) nas variáveis bióticas e abióticas em um viveiro de engorda de peixe. Foram demarcados três pontos de coleta localizados a 5, 10 e 23 m de distância do aerador, durante 15 dias consecutivos, sendo 5 dias antes do uso do aerador, 5 dias com o aerador ligado e 5 dias com o aerador desligado. As variáveis limnológicas estudadas não apresentaram diferenças significativas (P > 0,05) entre os três pontos de coleta, porém, em relação ao uso do aerador, variáveis como temperatura, transparência, pH, oxigênio dissolvido, bicarbonato, CO2 livre, fósforo total, ortofosfato, amônia, nitrato e nitrito diferiram significativamente (P < 0,05) com a agitação mecânica da água. Já a condutividade, alcalinidade, CO2 total e clorofila a não apresentaram diferenças significativas (P > 0,05) com o uso do aerador. A comunidade fitoplanctônica sofreu influência direta do aerador (P < 0,05), dominada pelas Chlorophyta, representando mais de 70% do total de organismos presentes, seguidas das Cyanophyta e Chrysophyta, porém estas últimas tenderam a aumentar após o uso do aerador, uma vez que estes grupos se adaptam rapidamente às mudanças do ambiente.

Due to the increasing use of artificial aerators in fish ponds, and to the lack of studies on this subject, this work studied some of the aspects associated with their use. The influence of a diffuser type aerator (AR 120) on the biotic and abiotic variables was evaluated in a fish pond. Three points of the pond were marked for the taking of samples: 5, 10 and 23 m from the aerator. Samples were taken every day for 15 consecutive days: 5 days before the use of the aerator, 5 days with the aerator functioning and 5 days with it not functioning. The limnological variables studied did not show significant differences (P > 0.05) when the three sampling points were compared, but regarding the use of the aerator, variables such as water temperature, transparency, pH, dissolved oxygen, bicarbonate, free CO2, total phosphorus, orthophosphate, ammonia nitrate and nitrite concentrations showed significant differences (P < 0.05) when the water was mechanically agitated. There were no significant differences (P > 0.05) with the use of the aerator regarding conductivity, alkalinity, total CO2 and chlorophyll a values. The phytoplanktonic community suffered as a direct influence of the aerator (P < 0.05). The community was dominated by Chlorophyta, representing more than 70% of the total organisms present, followed by Cyanophyta and Chrysophyta which tended to increase in number after the use of the aerator. This probably occurred because these groups adapt quickly to changes in the environment.