The Agro-Waste Production in Selected EUSAIR Regions and Its Potential Use for Building Applications: A Review

The purpose of this study is to provide a snapshot of the agro-waste production in Puglia, Molise, Albania and Montenegro, some of the regions belonging to EUSAIR (ADRIATIC-IONIAN REGIONS) correlating this aspect to the possible use of agro-waste in the building sector. EUSAIR is a functional area, facing the Adriatic sea, treating the marine, coastal and terrestrial areas as interconnected systems. In the first part of the paper, the state of the art about the current consumption of agricultural biomass is carried out referring to the ongoing research lines. It was shown that a great number of international studies have demonstrated that the agro-waste plays an important role in several fields. Moreover, several researchers conducted studies on hygrothermal, physical and acoustical properties of building materials made with biomass proving the potentiality to use this kind of by-product. Then, the state of the art regarding the production and current way of disposal of the agro-waste in the regions of the EUSAIR above mentioned was performed in order to outline the possible by-products which are suitable to be re-used in the building sector. The correlation existing between the agro-waste and the possible use in the building sector is finally presented, focusing on the legislative framework currently existing in each of the regions.

Surface Characteristics and Acoustical Properties of Bamboo Particle Board Coated with Polyurethane Varnish

Using bamboo particle board as a wall divider, a furniture component, or an automotive component with a sound absorber function may be a viable option for architects and engineers seeking to achieve desired acoustical qualities, including noise reduction. However, there is still a dearth of research on the effect of particle board finishing and coatings on acoustical sound absorption and noise reduction qualities. This study, therefore, aims to determine the surface characteristics and acoustical properties of bamboo particle board, coated with polyurethane (PU). The single-layer homogeneous particle boards were constructed using particles classified as fine and coarse with two different board densities, and coated with a high-quality PU lacquer. This study found that the coating treatment of 0.3 mm 0.6 mm succeeded to significantly decrease surface roughness, as well as thickness, swelling, and water absorption, with the thickness coating as a dominant factor compared with board density and board particle size. Adding a PU coating increases sound absorption performance at low frequencies, but significantly reduces acoustical properties at high frequencies. The increase of particle board density leads to the decrease in noise reduction coefficient capability. Results obtained from this study are useful to determine the optimal coating thickness in terms of evaluating acoustical panel products.

GTR/NBR/Silica Composites Performance Properties as a Function of Curing System: Sulfur versus Peroxides

In this work, conventional sulfur and two types of organic peroxides (dicumyl peroxide (DCP) and di-(2-tert-butyl-peroxyisopropyl)-benzene (BIB)) curing systems were used to investigate the possibility for tailoring of the performance properties of GTR/NBR blends reinforced with a variable content of highly dispersive silica (0–30 phr). The curing characteristics, static mechanical and acoustical properties, swelling behavior, thermal stability, and microstructure of the prepared composites were investigated. The results show that regardless of the curing system used, increasing the content of highly dispersive silica resulted in the improvement of the mechanical properties of the studied materials. It was observed that sulfur-based systems are the best choice in terms of cross-linking efficiency determined based on torque increment and cross-link density parameters. However, further analysis of the physico-mechanical properties indicated that the cross-linking efficiency does not match the performance of specimens, and the materials obtained using organic peroxides show higher tensile properties. This is due to the improved physical interactions between the GTR/NBR matrix and highly dispersive silica when using peroxide systems. It was confirmed using the analysis of the Wolff activity coefficient, indicating the enhanced synergy.

A hybrid method of predicting the acoustical properties of multi-layered materials

Many numerical and measuring approaches are widely used in predicting and analysing the acoustic performances of laminated materials for noise control applications. However, numerical methods generally require a set of non-acoustic parameters, and the measuring methods are not available for exceedingly thick materials. The main aim of this article is to address a hybrid approach of evaluating the normal incidence sound transmission loss and absorption coefficients of multi-layered materials. This method is performed with some special parameters that contain the sound transmission and reflection coefficients of each sub-layer of a multi-layer specimen and can be measured by a standing wave tube system. The accuracy and feasibility of the present method are validated by the experimental and numerical comparisons between different methods and samples. Moreover, this present approach can be applied as a numerical tool of estimating the acoustical behaviours of multi-layered structures in noise control treatments, such as automotive, building and aerospace industries.