Prediction of the acoustic insulation of a prefabricated wooden-based system for collective buildings

Using wood, a renewable, carbon sink material with outstanding thermal properties associated with the prefabrication process and its benefits, a construction system for multi-storey multifamily buildings based on prefabricated wooden panels was developed to act as a tool for meeting the national carbon neutrality targets. It will contribute to the promotion of increasingly sustainable cities that optimise the use of materials and rely on highly energy-efficient buildings. This sustainable alternative to conventional construction materials was designed to comply with the Portuguese needs, regulations, and regulatory requirements regarding construction, structural, functional, and logistics demands. As the acoustic behaviour of wooden buildings is a sensitive subject due to the wood's lightweight and poor insulation performance for low-frequency sounds, this work aims to analyse the panels regarding their acoustic behaviour through INSUL software. The predictions showed favourable results for airborne insulation and partially favourable for impact sound insulation.This work was supported by national funds through FCT – Fundação para a Ciência e a Tecnologia, within the scope of a Ph.D. scholarship (PRT/BD/152841/2021) granted by MIT Portugal Program to the first author

The wood moisture factor on the biological deterioration of wooden structures

With sustainability as a growing concern, the rehabilitation of buildings arises as one of the main forms of support for the construction sector. Rehabilitation, in comparison with new construction, is seen as a path to minimize the negative impacts of this activity by reducing, for example, the energy consumption of buildings and its consequent impact on energy production (still meeting the current needs for comfort) and the extraction of raw materials. Wood has a high potential for numerous purposes, also, it is a natural, renewable, and sustainable resource, presenting itself as a promising construction material with enormous importance for the bio-based economy. However, despite being a traditional material, reliable service life prediction of wooden structures continues to be a challenge. Like other biobased materials, wood can be subject to biological deterioration by fungi and insects. The biological agents, when combined with favourable conditions (e.g., temperature, air relative humidity, wood moisture content, etc.), can lead to simply aesthetic damage, reduction in indoor air quality, or compromising its resistant load capacity, creating a risk to human health and safety, in addition to an increase of repair and maintenance costs. Many approaches consider wood moisture content as the key factor to control the activation of the decay process, since fungal colonization of wood requires a minimum moisture content of around 20%. Moreover, though subterranean termites (one of the most damaging wood insects) are able to infest dry wood, contact to moisture is fundamental for effective installation of the colonies. This paper addresses moisture as a conditioning factor in the degradation of wood in construction. The role of water on the development of the biodeterioration processes, the transport of water within wooden elements, as well as how the current normative references address the issue are discussed. Finally, this work presents some of the exiting methods for continuous moisture content monitoring systems that, associated with regular maintenance, can be an alternative to chemical treatments, increasingly limited due to current environmental legislation- (undefined

Learning about Actions and Events in Shared NeMuS

The categorization process of information from pure data or learned in unsuper- vised artificial neural networks is still manual, especially in the labeling phase. Such a process is fundamental to knowledge representation [6], especially for symbol-based systems like logic, natural language processing and textual infor- mation retrieval. Unfortunately, applying categorization theory in large volumes of data does not lead to good results mainly because there is no generic and systematic way of categorizing such data processed by artificial neural networks and joining investigated conceptual structures. Connectionist approaches are capable of extracting information from arti- ficial neural networks, but categorizing them as symbolic knowledge have been little explored. The obstacle lies on the difficulty to find logical justification from response patterns of these networks [2]. This gets worse when considering induc- tive learning from dynamic data which is very important to Cognitive Sciences that considers categorization as a mental operation of classifying objects, actions and events [1]. We shall address the discoveries of our on-going investigation on the problem of inductively learning (IL) from dynamic data by applying a novel framework for neural-symbolic representation and reasoning called share Neural Multi-Space (NeMuS) used in the Amao system[4]. Instead of woking like traditional ap- proaches for ILP, e.g. [5], Amao uses a shared NeMuS of a give background knowledge (BK) and uses inverse unification as the generalization mechanism of a set of logically connected expressions from the Herbrand Base (HB) of BK that defines positive examples

Quantum phase transitions in alternating spin-(1/2, 5/2) Heisenberg chains

The ground state spin-wave excitations and thermodynamic properties of two types of ferrimagnetic chains are investigated: the alternating spin-1/2 spin-5/2 chain and a similar chain with a spin-1/2 pendant attached to the spin-5/2 site. Results for magnetic susceptibility, magnetization and specific heat are obtained through the finite-temperature Lanczos method with the aim in describing available experimental data, as well as comparison with theoretical results from the semiclassical approximation and the low-temperature susceptibility expansion derived from Takahashi's modified spin-wave theory. In particular, we study in detail the temperature vs. magnetic field phase diagram of the spin-1/2 spin-5/2 chain, in which several low-temperature quantum phases are identified: the Luttinger Liquid phase, the ferrimagnetic plateau and the fully polarized one, and the respective quantum critical points and crossover lines

Mechanical characterization of Iroko wood using small specimens

Despite their favorable physical and mechanical properties for structural use, tropical woods, such as Iroko (Milicia excelsa), present knowledge gaps to be filled mainly about their mechanical characterization, which currently limit their use or result in under- or overdimensioned structural elements. Visual classification, one of the most used methods for characterizing wood, is inaccurate in the case of Iroko due to the wide variety of geographical locations in which this species can be found. In addition, mechanical characterization using test pieces with structural dimensions leads to high and impractical costs. In this context, this study aims to verify the mechanical properties of Iroko (imported from the Republic of the Congo) from small size specimens, a process that is currently standardized only for softwoods, and to verify the correlation of different properties through bending properties and ultrasound tests. Prior to the bending tests, the speed of propagation of ultrasonic waves was measured using the direct method. The results obtained show a good correlation between density and bending properties and the velocity of propagation of ultrasonic waves

Discussão sobre a regularização da piscicultura brasileira: da produção à comercialização.

Introdução. Regularização de projetos aquícolas. Regularização de projetos aquícolas. Exemplos da abertura de empresa rural em outros países. Registro de Aquicultor e Licença de Aquicultor. Espécies cultiváveis. Exemplos de permissão de espécies exóticas para cultivo em outros países. Resumo do processo de regularização das pisciculturas em águas da União. Licenciamento ambiental de projetos de piscicultura. Particularidades do licenciamento em viveiros escavados, barragem e PCH e águas Estaduais. Custos do processo de regularização da área aquícola no Brasil. Exemplos internacionais sobre a regularização das áreas produtivas. Outorga de direito de uso de recursos hídricos para a piscicultura. Exemplos internacionais sobre cessão de uso das áreas produtivas. Regularização da produção. Incentivos para a produção. Tarifa da energia elétrica. Contribuição previdenciária. Regularização na comercialização. Despesca e Abate. Transporte. Guia de trânsito animal e outros documentos. Problemas causados pela falta de Inspeção Sanitária. Registros de estabelecimentos de processamento de pescado. SISB - Uma opção. Considerações Finais. Referências. Anexo 1 - Referências de interesse

Zeta function method and repulsive Casimir forces for an unusual pair of plates at finite temperature

We apply the generalized zeta function method to compute the Casimir energy and pressure between an unusual pair of parallel plates at finite temperature, namely: a perfectly conducting plate and an infinitely permeable one. The high and low temperature limits of these quantities are discussed; relationships between high and low temperature limits are estabkished by means of a modified version of the temperature inversion symmetry.Comment: latex file 9 pages, 3 figure