A Modeling Approach on the Correction Model of the Chromatic Aberration of Scanned Wood Grain Images

There always exists subjective and objective color differences between digital wood grain and real wood grain, making it difficult to replicate the color of natural timber. Therefore, we described a novel method of correcting the chromatic aberration of scanned wood grain to maximally restore the objective color information of the real wood grain. A point-to-point correction model of chromatic aberration between the scanned wood grain and the measured wood grain was established based on Circle 1 by adjusting the three channels (sR, sG, and sB) of the scanned images. A conversion of the color space was conducted using the mutual conversion formulas. The color change of the scanned images before and after the correction was evaluated through the L* a* b* color-mode-based ΔE* and the lαβ color-model-based CIQI (Color Image Quality Index) and CQE (Color Quality Enhancement). The experimental results showed that the chromatic aberration ΔE* between the scanned wood grain and the measured wood grain decreased and the colorfulness index CIQI of the scanned wood grain increased for most wood specimens after the correction. The values of ΔE* of the twenty kinds of wood specimens decreased by an average of 3.1 in Circle 1 and 2.3 in Circle 2, thus the correction model established based on Circle 1 was effective. The color of the scanned wood grain was more consistent with that of the originals after the correction, which would provide a more accurate color information for the reproductions of wood grain and had an important practical significance.

Fire performance of hybrid mass timber beam-end connections with perpendicular-to-wood grain reinforcement

PurposeThe fire resistance of timber structures is heavily dependent on the fire behaviour of the connections between its structural elements. The experimental study presented in this paper aimed to investigate the fire performance of glued-laminated timber beam connections reinforced perpendicular-to-wood grain with self-tapping screws (STS).Design/methodology/approachTwo full-size fire experiments were conducted on glulam beam-end connections loaded in flexure bending. Two connection configurations, each utilizing four steel bolts arranged in two different patterns, were reinforced perpendicular to wood grain using STS. The bolt heads and nuts and the steel plate top and bottom edges were fire protected using wood plugs and strips, respectively. Each connection configuration was loaded to 100% of the ultimate design load of the weakest unreinforced configuration. The test assemblies were exposed to elevated temperatures that followed the CAN/ULC-S101 standard fire time–temperature curve.FindingsThe experimental results show that the influence of the STS was significant as it prevented the occurrence of wood splitting and row shear-out and as a result, increased the fire resistance time of the connections. The time to failure of both connection configurations exceeded the minimum fire resistance rating specified as 45 min for combustible construction in applicable building codes.Originality/valueThe experimental data show the effectiveness of a simple fire protection system (i.e. wood plugs and strips) along with the utilization of STS on the rotational behaviour, charring rate, fire resistance time and failure mode of the proposed hybrid mass timber beam-end connection configurations.

PRODUÇÃO DE MÓVEIS RÚSTICOS COM MADEIRA RESIDUAL DA FLORESTA AMAZÔNICA

A exploração madeireira e as conversões de áreas de florestas para uso alternativo do solo na região Amazônica, em especial no estado do Amapá, resultam em grandes quantidades de madeira residual que em geral são abandonadas em campo. Essa problemática da geração de resíduos florestais e principalmente do desperdício e da falta de alternativas para o seu uso apropriado, resultou nesta proposta de pesquisa que teve como objetivo a produção de móveis rústicos artesanais como uma alternativa para o uso da madeira residual da floresta Amazônica. Foram coletados resíduos de madeira deixados no campo após a colheita de floresta Amazônica manejada, destinando-os à fabricação de mobiliário rústico, obtendo como resultado final os seguintes protótipos: banco peça de tora única, balcão para barzinho, aparador de madeira, pia de madeira, mesinha de centro com tampo de madeira, mesinha de centro com tampo de vidro. Foi testada a viabilidade técnica para fabricação artesanal das peças de mobiliário utilizando máquinas e ferramentas portáteis. Os resíduos de madeira se mostraram excelente fonte de matéria-prima para movelaria rústica possibilitando múltiplas alternativas de designs, apesar de certas dificuldades terem sido evidenciadas no decorrer do processo como: peso, dureza, orientação da grã da madeira, entre outras que, no entanto, não impossibilitaram a produção dos móveis. O uso da madeira residual para fabricação de móveis rústicos pode se constituir num novo e empreendedor negócio para a região Amazônica, contribuindo para a geração de renda local. Verificou-se que o método empregado proporcionou a produção de móveis originais, o que agrega valor à sua comercialização. Palavras-chave: trabalho artesanal; empreendedorismo; projeto. Rustic furniture production with wood residues from the Amazon forest ABSTRACT: Harvesting and conversions of forest areas to alternative land use in the Amazon region, especially in the Amapá state, result in large amounts of wood residues that are generally abandoned. This problem about the forest residues and mainly of its loss and the lack of alternatives for its proper use, resulted in this research proposal that aimed to produce handcrafted rustic furniture as an alternative to the use of wood residues from the Amazon forest. Wood residues left in the field after harvesting the managed Amazon forest were collected and destined for the manufacture of rustic furniture, obtaining the following prototypes as a final result: log bench, bar counter, wood dresser, wood sink, coffee table with wood top, coffee table with glass top. The technical feasibility of handcrafting furniture pieces using portable machines and tools were tested. Wood residues proved to be an excellent source of raw material for rustic furniture, enabling multiple design alternatives, although certain difficulties were evidenced during the process such as: weight, hardness, wood grain orientation, among others that did not prevent the furniture production. The use of wood residues to rustic furniture manufacture can constitute a new and entrepreneurial business for the Amazon region, contributing to the generation of local income. It was found that the method used provided the production of original furniture, which adds value to its marketing. Keywords: artisan work; entrepreneurship; design.

Sistem Bantu untuk Pengrajin dalam Menentukan Kayu Terbaik Terbaik untuk Bahan Gitar dengan Menggunakan Matode Moora

<p>Penelitian ini bertujuan untuk membantu pengrajin kayu di Dongkelan, Krapyak, Yogyakarta dalam menentukan kayu terbaik untuk dijadikan sebagai bahan gitar, karena sering terjadi keluhan dari para pembeli bahwa bahan yang dijadikan bahan gitar cepat lapuk dan kusam dari segi warnah. Berdasarkan permasalahan tersebut, dicari suatu solusi dengan menggunakan metode <em>Decision Support System</em> <em>Multi Objective Optimization on the basic of Ratio Analysis</em><em> </em>(MOORA) serta dibantu oleh pakar dalam menentukan kriteria yang tepat berkaitan penentuan kayu terbaik yang digunakan dalam pembuatan bahan gitar, setelah berdiskusi panjang ditemukan hasil kriteria yang tepat berdasarkan permasalahan, berupa kriteria kekuatan kayu, serat kayu, tekstur, dan berat kayu. Semua kriteria tersebut, kemudian diproses dengan menggunakan metode MOORA, dengan data yang digunakan sebanyak 29 jenis data kayu, yang diperoleh dari pengrajin yang ada di wilayah tersebut. Setelah diproses, diperoleh hasil 3 kayu terbaik yang layak untuk digunakan sebagai bahan pembuatan gitar secara berurutan dalah kayu Bubinga dengan nilai 18,36785, kayu Bocote dengan nilai 17,33385, dan kayu Eboni dengan nilai 17,33385 dari beberapa pilihan alternatif kayu yang ada. Membuktikan hasil dari metode MOORA<em>, </em>maka dilakukan responden secara langsung dengan memberikan hasil metode kepada pakar pembuat gitar. Dari 15 pakar pembuat gitar, 13 mengatakan setuju dengan peringkat 3 terbesar, dan 2 mengatakan kurang setuju. Sehingga ditemukan tingkat akurasi berdasarkan penilaian pakar sebesar 86,67 %.</p><p> </p><p><strong>Abstract</strong></p><div><p><em>This study aims to assist wood craftsmen in Dongkelan, Krapyak, Yogyakarta in determining the best wood to be used as guitar material, because there are frequent complaints from buyers that the material used for guitar is rotten quickly and is dull in terms of color. Based on these problems, a solution was sought using the Multi Objective Optimization on the basic of Ratio Analysis (MOORA) Decision Support System method and assisted by experts in determining the right criteria related to determining the best wood used in making guitar materials, after a long discussion found the results. the right criteria based on the problem, in the form of wood strength criteria, wood grain, texture, and wood weight. All of these criteria are then processed using the MOORA method, with the data used as much as 29 types of wood data, which are obtained from craftsmen in the area. After processing, the 3 best woods that are suitable for use as a guitar-making material are Bubinga wood with a value of 18.36785, Bocote wood with a value of 17.333385, and Eboni wood with a value of 17.333385 from several alternative wood choices. . Proving the results of the MOORA method, the respondents directly gave the results of the method to guitar-making experts. Of the 15 expert guitar makers, 13 said they agreed with the third largest ranking, and 2 said they disagreed. So that it found the level of accuracy based on expert judgment of 86.67%. </em></p></div><p><strong><br /></strong></p>

Single-Sided Microwave Near-Field Scanning of Pine Wood Lumber for Defect Detection

Defects and cracks in dried natural timber (relative permittivity 2–5) may cause structural weakness and enhanced warping in structural beams. For a pine wood beam (1200 mm × 70 mm × 70 mm), microwave reflection (S11) and transmission (S21) measurements using a cavity-backed slot antenna on the wood surface showed the variations caused by imperfections and defects in the wood. Reflection measurements at 4.4 GHz increased (>5 dB) above a major knot evident on the wood surface when the E-field was parallel to the wood grain. Similar results were observed for air cavities, independent of depth from the wood surface. The presence of a metal bolt in an air hole increased S11 by 2 dB. In comparison, transmission measurements (S21) were increased by 6 dB for a metal screw centered in the cavity. A kiln-dried pine wood sample was saturated with water to increase its moisture content from 17% to 138%. Both parallel and perpendicular E-field measurements showed a difference of more than 15 dB above an open saw-cut slot in the water-saturated beam. The insertion of a brass plate in the open slot created a 7 dB rise in the S11 measurement (p < 0.0003), while there was no significant variation for perpendicular orientation. By measuring the reflection coefficient, it was possible to detect the location of a crack through a change in its magnitude without a noticeable change (<0.01 GHz) in resonant frequency. These microwave measurements offer a simple, single-frequency non-destructive testing method of structural timber in situ, when one or more plane faces are accessible for direct antenna contact.

Resource-saving technologies in the production of glued laminated lumber with a glue line of increased strength

One of the main problems of forestry is increased number of fellings and deforestation. Development of promising technologies in woodworking industry is one of the solutions to this problem. These technologies make it possible to reduce the production cost through the use of cheap and non-scarce materials and improve the quality of the resulting products to the level of premium products by improving the quality of the adhesive bond. The aim of the study is to obtain high-quality glued timber from non-grade oak wood (Quercus Robur L.) based on urea formaldehyde (resin, subsequently treated with ultrasound and constant magnetic field. The studies have shown that strength values of the adhesive bond based on the resin, subjected to shear testing along the wood grain, are significantly higher than that of the control specimens obtained using standard technology. Also, additional studies of internal stresses in the glue line and analysis of the microstructure were carried out. They enable obtain an explanation of the strengthening effect of adhesive joint.

Improving the quality of the band saw cut

This article is devoted to the study of the dynamic characteristics of the band sawing process to improve their efficiency. The object of study is: band saw, softwood. A screening experiment was carried out when sawing with band saws to identify key influencing factors on the quality of the treated surface (roughness) and sawing force (sawing power). Rational values of key influencing factors were determined. The effectiveness of the sawing regimes with band saws was evaluated. In the course of laboratory tests of the new saw, it was found that the moisture content of the wood has the maximum effect on the quality of the sawing walls. According to the degree of influence of factors, the roughness of the cut depends on the moisture content of the wood, the feed per tooth, the type of cutting relative to the wood grain and the height of the cut. As a result of a multivariate experiment, two regression equations were obtained for the assumed roughness of the cut and the cutting power. The estimation of the significance of the coefficients in the given interval of variation of the influencing factors is carried out.

Three-dimensional numerical and experimental study of fracture saturation in panel paintings

Panel paintings—complex multi-layer structures consisting of wood support and a paint layer composed of a preparatory layer of gesso, paints, and varnishes—are among the category of cultural objects most vulnerable to relative humidity fluctuations and frequently found in museum collections. The current environmental specifications in museums have been derived using the criterion of crack initiation in an undamaged, usually new gesso layer laid on wood. In reality, historical paintings exhibit complex crack patterns called craquelures. The present paper analyses the structural response of a paint layer with a virtual network of rectangular cracks under environmental loadings using a three-dimensional model of a panel painting. Two modes of loading are considered—one induced by one-dimensional moisture response of wood support, termed the tangential loading, and the other isotropic induced by drying shrinkage of the gesso layer. The superposition of the two modes is also analysed. The modelling showed that minimum distances between cracks parallel to the wood grain depended on the gesso stiffness under the tangential loading. Despite a nonzero Poisson’s ratio, gesso cracks perpendicular to the wood grain could not be generated by the moisture response of the wood support. The isotropic drying shrinkage of gesso produced cracks that were almost evenly spaced in both directions. The modelling results were cross-checked with crack patterns obtained on a mock-up of a panel painting exposed to several extreme environmental variations in an environmental chamber.

Image Definition Evaluations on Denoised and Sharpened Wood Grain Images

Decorative paper and wood veneer have been widely used in the surface decoration of wood-based panels. These surface decoration methods require two-dimensional image acquisition of natural wood grain to obtain the digital grain. However, optically scanned images sometimes produce noise during the process of image acquisition and transmission. In this situation, scanned images cannot be used directly in wood grain reproductions. To reduce noise and retain or strengthen the image sharpness, studies are mostly aimed at the improvement of classic denoising algorithms and edge width-based sharpness evaluation algorithms. To enhance accessibility for common users, four kinds of wood grain images with distinct colors were chosen, and the noise filter (Dust & Scratches) and sharpen filter (Unsharp Mask, USM) were used to denoise and sharpen the images. According to the properties of the two filters, image definition in this study was considered from two aspects: detail retention and sharpness retention. To have an objective evaluation on the definition of denoised and sharpened images, two types of evaluation functions Roberts gradient function (RGF) and modulation transfer function (MTF) were introduced. The purpose of this study was to estimate the image definition by exploring the relationships between the evaluation functions and the commonly used filters in order to allow the required wood grain images to be quickly and accurately processed by common users. The results showed that RGF was only applicable to the case where the two parameters in Dust & Scratches were changed individually, while MTF was not suitable in any case. When both parameters were changed, the required denoising scheme could be obtained through PSNR and SSIM. For the images with distinct colors, even if they were acquired in the same way, denoising them with the same parameter setting was not recommended. For sharpness retention, the values of Radius and Amount in USM were given, and when the Threshold value was set to 20 (levels), the sharpness of the wood grain images barely changed. In this case, both RGF and MTF were suitable to evaluate the sharpness of the wood grain images sharpened by USM.