Search Results (21)

The recycling and reuse of wood have gained importance as strategies for reducing construction waste, lowering costs, and promoting circular practices in the built environment. This study evaluates the performance of recycled wood particle/epoxy composites (WPECs) for façade applications by prototyping panels produced from granulated degraded wood bonded with epoxy resin and coated with intumescent fire-retardant paint. The panels were design to meet standards for ventilated façade applications in accordance with EN 310-93 and ASTM D1037-06a and relevant building codes for facade cladding. Three replicates of each panel type were tested under controlled laboratory conditions to assess water absorption, equilibrium moisture content, capillarity, fire resistance, and mechanical performance. Moisture measurements were performed at immersion and drying intervals of 12, 24, 36, 72, and 120 h for four WPEC types manufactured with pine, beech, oak, and olive fibers. Statistical evaluation using SPSS (one-way and two-way ANOVA) confirmed significant species effects across most parameters. Results indicated that olive and oak WPECs provided the highest dimensional stability under moisture exposure, with olive additionally demonstrating superior compressive strength (35.45 MPa) and hardness (˂10,000 N). Pine and beech WPECs exhibited intermediate bending strength (≈10 MPa) and elasticity, while oak contributed stable swelling values despite lower strength. Fire resistance tests suggested relative improvements, although further standardized evaluation is needed. Collectively, olive and oak WPECs emerged as the most promising façade materials, combining durability, mechanical strength, and sustainability. Full article

Wood is often used as an interior surface finish in buildings, including exposed cross-laminated timber panels and other structural mass timber members. Building occupants generally have a positive reaction to visible wood elements used in building interiors due to the visual qualities associated with wood being a natural material. This study aims to identify any thermal comfort impacts of wood interior environments using subjective occupant-reported perceived thermal sensation during two experiments conducted in a climate chamber fitted with either white-painted gypsum wallboard or unfinished laminated Douglas Fir wall panels. In the first experiment, the thermal environment was continually varied while the visual stimulus of the wall type remained constant. Irrespective of wood or white wall treatment type, thermal history played a significant role in the perceived thermal comfort of participants under continually modulating temperatures. In the second experiment, a slightly warm steady-state thermal environment was maintained while one of the two wall treatments was revealed from behind a black curtain. While the shift in thermal sensation toward neutral was greater with wood walls than with white walls, the difference was not found to be statistically significant and appears to diminish after 15 min of exposure to the new visual surroundings. Full article

Wooden panel paintings (WPPs) are among the most significant historical artworks that must be preserved for future generations. Ensuring their long-term conservation requires a comprehensive characterization of their condition, making monitoring an essential process. Thus, the primary objective of this study is to provide a comprehensive overview of the current techniques employed to study support deformations in WPPs, categorizing them into localized and full-field methods. Specifically, we provide information about linear potentiometric transducers, the Deformometric Kit, and Fiber Bragg Grating sensors as techniques that provide information about specific and isolated points on the artwork’s surface. On the other hand, digital image correlation, stereo-correlation, mark-tracking, 3D modeling techniques, and the moiré method, are discussed as techniques that analyze the entire surface or a significant part of the artwork. Each method has advantages and limitations, depending on the type of monitoring needed and the desired information. Nevertheless, these techniques contribute to understanding the behavior of the artworks’ materials under environmental fluctuations or restoration interventions, aiding the development of targeted and effective conservation strategies. Furthermore, this study seeks to evaluate the effectiveness of these methods in various conservation contexts and offers practical guidelines to assist conservators and researchers in selecting the most appropriate approach to support the long-term conservation of these invaluable historical artworks. Full article

This paper describes an innovative method developed by the authors to support basic decisions concerning the structural restoration of a large historical panel painting which had been damaged by inappropriate attachment to a wall and ongoing exposure to severe changes in environmental humidity. The Lapidazione di Santo Stefano is a large panel (2.78 × 3.92 m²) painted by Giorgio Vasari in 1571 and has been housed since then in the Church of Santo Stefano dei Cavalieri in Pisa (Italy). Its wooden support is made of large horizontal planks glued together along their edges and stiffened by vertical, dovetailed crossbeams. The panel was tightly fastened to a church wall with several rigid bolts; due to the moisture cycling produced by rainwater leakage and a subsequent “compression set”, it had developed severe tension stresses perpendicular to the grain, resulting in cracks affecting both the wood and the paint layers. To decide how to carry out the structural restoration of the panel, it was necessary to know whether slippage could occur between the panel and crossbeams during seasonal variations in environmental humidity. Without slippage, tensile stresses would be generated in the wood and could produce further cracks and damage the paint layers. An in situ monitoring method for assessing the possibility of slippage was developed and implemented. An analysis of data collected over a period of 6 months before the structural restoration confirmed that adequate slippage was possible; hence, the decision to fully repair the cracks was taken. Monitoring continued for a year after restoration and confirmed the previous findings. This paper describes the monitoring method, the equipment used, the results of its implementation and its value as a preventive conservation tool. Full article

Ajami, a technique of painted wood paneling, was popular in the Ottoman Empire from the 17th to the late 18th centuries. Ajami art became prominent in Syria after the decline of tile production, and it rose to a sophisticated level of art in both local and global markets. Today, however, Ajami art has become almost forgotten and unknown by the modern generation, due to being an exclusive art that can be seen only in palaces, museums, and historical houses. This study investigates the traditional method and techniques of making Ajami, with a focus on the work of a renowned Syrian Ajami art master artisan named Mr. Abdulraouf. The study aims to identify and document the traditional method of Ajami production and determine the materials and techniques used for making Ajami. The study found that Ajami art consists of natural elements that are utilized in four main stages; foundation, design, painting, and finishing. The artisans have a strong preference for floral and geometric designs, influenced by Islamic religious beliefs. The findings of this study could serve as an educational guide to preserve heritage and make it presentable for the present and future generations. Full article

The economic viability of guayule as an industrial crop for natural rubber production depends largely on the potential valorization of these co-products. According to the studies carried out on the subject, there is a broad consensus on the added value of the resin and bagasse in different fields of application. The process of extracting natural rubber from guayule produces mainly bagasse (±80% of the total dry mass) and resin (±10% of the total dry mass). According to guayule research, high-value co-products significantly improve the economic viability of guayule as an industrial crop and offset a substantial portion of the cultivation and processing costs. According to studies, resin remains the most fluctuating value; reducing this uncertainty, through future research on resin applications, it is essential to the success of guayule as a natural rubber raw material. It finds applications in different industrial fields, such as coatings, varnishes, paints, treated wood, biocontrol agents and controlled-release formulations. Bagasse is composed primarily of cellulose, hemicellulose, lignin and resin, and has a high calorific value, making bagasse a suitable fuel for on-site combustion to produce electricity and thermal energy. Bagasse combustion in this scenario is less complex than the logistics of biofuel production. Resin-containing guayule bagasse has been combined with a plastic binder to make high-density composite panels resistant to termite degradation. In addition, the resinous material can be solvent-extracted and used to impregnate wood with raw resin extract so that the wood is protected from destructive organisms. Guayule bagasse containing resin can modify the soil nature and improve the growth of vegetables compared to de-resinated bagasse. Full article

HERIe was used to model the effect of changes to indoor climate on the risk of humidity-induced mechanical damage (cracking and plastic deformation) to wooden panels painted with stiff gesso in two Norwegian medieval stone churches: Kinn (mean relative humidity (RH, %) = 79%) on the humid west coast, and Ringsaker (mean RH = 49%) in the drier eastern part of the country. The risk involved in moving cultural heritage objects (paint on wood) between the churches and a conservation studio with more “ideal”, stable conditions was also modeled. A hypothetical reduction in RH to ~65% and, proportionally, of the climate fluctuations in Kinn, and an increase in the RH in Ringsaker to a more stable value of ~63% via conservation heating, were found to improve (Kinn) and uphold (Ringsaker) the conformity to relevant standards and significantly reduce the risk of damage, except in the scenario of moving objects from Ringsaker to a conservation studio, when the risk would increase. The use of conservation heating could save ~50% of the heating cost. The estimated risk reductions may be less relevant for objects kept in situ, where cracks in the original paint and gesso have developed historically. They may be more relevant when moving original objects away from their proofed climate into a conservation studio for treatment. Full article

The most important painter from Urbino in the last decades of the 15th century (1439 ab.–1494) was Giovanni Santi, the father of Raphael. The lack of scientific literature about Santi’s practice and the possible peculiar role of Urbino in the development of painting techniques in northern Italy suggested in-depth investigations of the entire corpus of his paintings. A well-established sequence of multispectral imaging, spectroscopic and microscopic investigations was performed on 24 wood panel paintings and 2 canvases attributed by most scholars to Giovanni Santi (1439 ab.–1494) to collect a large set of significant data. This systematic research allowed his painting technique to be defined, starting from the type of supports he used and from the features of the underdrawing, which quite frequently included characteristic regular hatching. The pigments used were widely investigated by means of ED-XRF and reflectance spectroscopy (vis-RS); a meaningful multivariate statistical method (PCA and HCA analysis) was also applied to the ED-XRF dataset acquired for representative hues. In particular, the vis-RS technique proved to be a simple and effective diagnostic tool to detect many pigments, including indigo, and to distinguish between two different types of red lakes, avoiding sampling and more complex analyses. Santi used lead white, Fe-Mn-based pigments, vermilion, red lake, natural blue ultramarine, azurite, copper-based green pigments (particularly verdigris), lead-tin yellow, scarcely ever orpiment and, in a few green mixtures, also indigo. Despite the palette being linked to tradition, the master appeared to introduce some peculiarities, such as the addition of glass powder, and mixing pigments both in a traditional way and using them to create chromatic effects unusual for his time. This research confirmed that the systematic use of the integrated non-invasive methods is highly representative, and the results of this wide diagnostic campaign provided a significant dataset which allowed the implementation of a scientific database related to central Italy Renaissance paintings and materials. Full article

The study aims to enhance our knowledge of the materials and techniques applied in the making of Russian, portable ecclesiastical paintings produced after the 16th century, and to evaluate a pilot, non-destructive, non-invasive, research methodology proposed for their examination. Based on research relating to the historical background of their production and distribution in the South, the availability of materials and the applied techniques, a non-destructive, non-invasive methodology is exploited to examine three triptychs and two polyptych side panels belonging to the collection of the Benaki Museum. As their small size and excellent state of preservation prohibit sampling, a study scheme based on visual examination, the implementation of a series of spectral imaging techniques (VIS, IRRFC, SWIR, UVL, RTI, X ray) and a non-invasive micro XRF analysis is tested. Fiber and wood-type identification are carried out microscopically. The collected information relates to the making of the frames and the supports, the design, the use of metal foils and pigments, the order of application of paint layers and the rendering techniques. Due to the non-destructive, non-invasive character of the procedure, organic constituents are not thoroughly examined. Use of an expected palette was confirmed, but the modelling proved rather sophisticated. Among the most interesting finds were the use of distinct pigment mixtures for the underpaints of the flesh parts and certain deviations from the expected rendering techniques. The methodology proved very effective in terms of its output, the global approach of the construction technique, the user-friendly application, the low cost and time consumption factors. Full article

Because the surface of MDF is not aesthetically pleasing, it usually needs to be veneered and then painted, but such a board releases harmful VOCs, among which Benzene Series is the most harmful. Benzene and its series are a group of carcinogenic compounds. With the diluents of nitrocellulose (NC)-lacquered MDF as the research objects, the release of the Benzene Series was studied to provide a scientific basis for pollution control and a reference for eco-friendly paint production. The attenuant of NC paint, anhydrous ethanol, ethyl acetate and solvents mixed with different alcohol ester ratios were used as diluents in NC lacquer. Two kinds of wood-veneered MDF with different thickness (18 mm and 8 mm) were coated with NC lacquer and analyzed in the experiment. The gas was collected using a small environmental chamber and the Benzene Series was analyzed using GC-MS. The concentration of Benzene Series released by MDF was 316.24 μg·m⁻³, and that of the NC-lacquered MDF with thicknesses of 18 mm and 8 mm were 284.44 μg·m⁻³ and 281.06 μg·m⁻³, respectively. The MDF released 14 kinds of Benzene Series, and the NC-lacquered MDF with two thicknesses released 18 kinds of it. The release concentration order of Benzene Series in NC-lacquered MDF with different diluents of the 18 mm thick panel was NC-M, NC-A, and NC-E from high to low. The lowest concentration of it occurred when the ratio of anhydrous ethanol to ethyl acetate was 1:3, and the lowest amount of components were at the ratio of 1:2. The concentration of Benzene Series released by MDF is higher than that released by the NC-lacquered MDF. Thickness has no effect on the type of release. The thicker MDF was, the higher the concentration was. The alcohol and ester thinner can control the release of Benzene Series from the source, and the optimal mixing ratio was 1:3. Full article

Recycled recovered wood, for example, from historic buildings, containing biocides, fire retardants or anti-weather paints is an attractive material for manufacturing composite wood panels which can be used for decoration as well as load-bearing walls with a typical patina. This paper investigates the effect of four inorganic wood preservatives—CuSO₄·5H₂O, ZnCl₂, H₃BO₃ and (NH₄)₂SO₄—commonly used in the past, with the focus on their effect on the quality of wood bonding. The milled surfaces of Norway spruce (Picea abies Karst L.) wood were treated with 0.5, 1 and 2% aqueous solutions of these preservatives. The effect of preservatives in spruce wood was evaluated: (1) by its wettability with the drops of redistilled water, measuring the contact angles; (2) by the shear strength of the “spruce wood—polyurethane (PUR) Kestopur 1030 glue” interphases according to the standard EN 205; (3) by microscopic analysis of the “wood—PUR” interphases. The wettability of spruce wood worsened when using ZnCl₂, by a maximum of 28.2%, but on the contrary, it improved due to other preservatives mainly by using (NH₄)₂SO₄, at a maximum of 22.9%. In general, the shear strength of glued joints “wood—PUR” continually decreased with higher concentrations of all the preservatives. The most significant decrease of adhesion “wood—PUR”, by 19.8% from 10.66 MPa to 8.55 MPa, was caused by 2% ZnCl₂ used for the treatment of both spruce wood specimens in interphase with the PUR glue. On the contrary, the less significant decrease of adhesion “wood—PUR”, by 2.5%, was caused by 0.5% (NH₄)₂SO₄ applied only on one surface of the two inter-bonded spruce wood specimens. The effects of preservatives on the wood wettability and its adhesion with PUR glue were partly confirmed by microscopic analysis. Full article

The potential of any multi-analytical and non-invasive approach to the study of cultural heritage, both for conservation and scientific investigation purposes, is gaining increasing interest, and it was tested in this paper, focusing on the panel painting Madonna della Tenda (Musei Reali, Turin), identified as a 16th-century copy of the painting by Raffaello Sanzio. As a part of a broader diagnostic campaign carried out at the Centro Conservazione e Restauro, La Venaria Reale in Turin, Italy, the potential of the combination of X-ray radiography, pulse-compression thermography, macro X-ray fluorescence, and IR reflectography was tested to investigate the wooden support and all the preparatory phases for the realization of the painting. The results of the optical microscopy and SEM/EDS analyses on a multi-layered micro-sample were used for a precise comparison, integration, and/or confirmation of what was suggested by the non-invasive techniques. Particularly, the radiographic and thermographic techniques allowed for an in-depth study of a hole, interestingly present on the panel’s back surface, detecting the trajectory of the wood grain and confirming the presence of an old wood knot, as well as of a tau-shaped element—potentially a cracked and unfilled area of the wooden support—near the hollow. The combination of radiography, macro X-ray fluorescence, Near Infrared (NIR), and Short Wave Infrared (SWIR) reflectography allowed for an inspection of the ground layer, imprimitura, engravings, and underdrawing, not only revealing interesting technical-executive aspects of the artwork realization, but also highlighting the advantages of an integrated reading of data obtained from the different analytical techniques. Full article

Wood has a wide range of applications in the artistic field, most of the time used as a support for works of art, for example, in panel paintings. Compared with stones and metals, wood is by far the material most utilised for sculptures. Through the identification of wood species, a study of timbers used in statuary in Europe, with a deeper exploration of the works of art preserved in Italy, can provide further insights for historical–artistic studies. Indeed, in reality, generic wood does not exist, but there are different timbers. This is a notion that the wood fine carving artists/craftsmen knew well. The initial idea of this study was to verify whether timber features could influence the formal results in figurative carving; therefore, a specific database that had been developed to catalogue the carving works was used for which the identification of wood species was carried out through reliable methodologies. The aim of this research was to analyse the relationship between the timber species used in statuary, the formal results of carving, and the thickness of the preparatory layer, through the data stored in a specific database, called ArISStArt. It contains a sort of registry of artistic carving and inlay works: For each artefact, a record was compiled consisting of different fields, which contains the historical–artistic information available, including the images of the artefact and also types of timber/s used for its creation, with a link to the relative field. The number of the recorded artefacts is, at present, 480. On most of the artefacts, more than one sample was taken; therefore, the total number of identifications carried out corresponds to 691. Based on the results, the vast majority of wooden statuary is carved from hardwoods, more specifically hardwoods, with diffuse porosity and small variations in density within the growth ring. The timber most present is poplar, followed by lime and walnut. With the listed three timbers, almost 80% of the artefacts recorded in ArISStArt were created. Full article

The scattering phenomenon is known to be of great importance for the acoustic quality of a performance arts space. The scattering of sound can be achieved in different ways: it can be obtained by the presence of architectural and/or decorating elements inside a room (e.g., columns, statues), by the geometry and roughness of a surface (e.g., Quadratic Residue Diffuser (QRD)) and by the diffraction effect occurring when a sound wave hits the edges of an obstacle. This article deals with the surface scattering effects and the diffusion phenomenon only related to MDF and plywood panels tested by disposing the wells both horizontally and vertically. The test results undertaken inside a semi-reverberant room and inside a large reverberant room have been compared to highlight the success and the failure of the measuring methodologies. In detail, according to the existing standards and regulations (i.e., ISO 17497—Part 2), diffusion measurements have been undertaken on a few selected types of panel: two QRD panels (made of Medium Density Fiberboard (MDF) and plywood) with and without a smooth painted solid wood placed behind the QRD. The panels have been tested inside two rooms of different characteristics: a semi-anechoic chamber (Room A) and a large reverberant room (Room B). The volume size influenced the results that have been analyzed for both chambers, showing an overlap of reflections on panels tested inside Room A and a clear diffusion response for the panels tested inside Room B. In terms of the diffusion coefficient in all the octave bands between 125 Hz and 8 kHz, results should not be considered valid for panels tested in Room A because they were negatively impacted by extraneous reflections, while they are reliable for panels tested in Room B. Full article

Retro-reflectivity is a promising surface capability, which has attracted the interest of researchers for building applications in order to counteract Urban Heat Island (UHI) effects. This work aims at studying the impact of the substrate material on the optic performance of retro-reflective (RR) coatings. Three types of substrate materials were investigated: smooth pine wood panels, rough plywood panels, and smooth acetate sheets. The RR coating samples were made by firstly adding a high reflective white paint onto the substrate material and a homogeneous RR glass beads layer on the top. As a reference case, also diffusive samples, without RR beads, were developed. Samples have been tested through a spectrophotometric and an angular reflectivity analysis. Results show that, despite a lower global reflectance of the RR samples with respect to the diffusive ones, the glass beads coating provides a good retro-reflective capability to all the diffusive samples. Additionally, the roughest RR sample exhibited the highest RR capability of up to 16%, with respect to the other smoother samples. Future developments may involve the optimum design of RR coatings, in terms of their optic performance by varying the substrate materials and roughness, the glass beads density and dimension. Full article