Analytical Assessment and Comparison of Wood Strength and Density Effect in the Design of Three Connection Types in Double-Shear

This work presents the results of three connection types in double-shear with dowel fasteners, using the simplified equations from the Eurocode 5. All design parameters were established and compared using three different wood strength and density properties, which constitute the members connections. Eighty-one connections were obtained, allowing to conclude about the number of fasteners needed to the applied tensile load. An increase in the number of dowels was obtained with the increased applied tensile load, lower dowel diameter, lower wood density, and lower strength material in all connection types in the study. The design characteristic load-carrying capacity per shear plane and fastener also decrease with the previously considered parameters.

Engineered bamboo: The promising material for building and construction application in Indonesia

There is a rising gap between supply and demand of wood as building and construction materials. The search of alternative materials to fill in the gap is an urgent concern. Bamboo is one of locally abundant resources; 88 out of 135 species growth in Indonesia is an endemic. It is a renewably material and has comparable characteristics to wood. Notable efforts to reduce the variability of raw bamboo have led to the improved physical and mechanical properties of the engineered bamboo. Laminated bamboo and hybrid laminated bamboo-wood had superior wood strength in comparison to the raw materials. Laminated bamboo produced from andong (Gigantochloa pseudoarundinacea (Steud.) Widjaja), mayan (Gigantochloa robusta Kurz), vertically laminated andong bamboo comparable to wood strength class I, I-II and II, respectively. Furthermore, hybrid laminated bamboo-wood andong-manii (Maesopsis eminii Engl.), andong-mayan-jabon (Anthocephalus cadamba (Roxb.) Miq.) comparable to wood strength class II and III, respectively. The properties improvement of engineered bamboo demonstrates the potential application of laminated bamboo as a substitution for building and construction material.

Nitrogen Fertilization Increases Windstorm Damage in an Aggrading Forest

Storms are the most significant disturbance events in temperate forests. Forests impacted by nitrogen deposition may face more severe storm damage as changes in soil and wood chemistry impact tree growth allocation, wood strength, and species composition. To examine these potential effects of nitrogen deposition, we measured tree damage from a windstorm in an aggrading forest that is part of a nitrogen fertilization experiment. We discovered that within the nitrogen fertilization treatment area there was significantly more basal area and stems damaged when compared to the reference treatment, and the nitrogen fertilization treatment had more snapped and severely damaged trees. Additionally, the effect of treatment and amount of damage to trees was different depending on tree species. If our results are indicative of the large and globally-distributed regions of temperate forests impacted by nitrogen deposition, then the increased windstorm disturbance risk posed by climate change could be more significant due to the effects of nitrogen deposition.

Theoretical determination of pit membrane natural frequency for destruction by resonance effect

The low permeability of many wood species causes significant problems during processing. Industrial methods used for increasing wood permeability reduce strength properties, are energy consuming, and are not viable economically. Destruction of pit membranes in wood cell walls can provide an increase in wood permeability without affecting wood strength properties. It can be accomplished using resonance applied to the pit membranes. Theoretical analysis and calculations have been performed to determine pit membrane (torus and margo) natural frequency. Membrane natural frequencies of bordered pits of Norway spruce are in the range of 3 to 11 MHz. Water in the pit chamber did not have a significant effect on the resonant frequency of the membrane. The main limitation of the amplitude of membrane fluctuations inside the pit chamber was the width of the chamber. Two methods to initiate resonance frequency for pit membrane destruction have been suggested, namely, alternating electric field application and microwave energy pulsation.

The nuances of toning and wood dyeing in the process of creating the original wooden sculptures

  This article states that the ways to improve the decorative qualities of wood have been known to mankind since ancient times. The techniques of woodworking material have improved over years. The author underlines the importance of proper choice of finishing materials, as it intended to preserve the cultural objects, as well as produce certain aesthetic perception. Therefore, the choice of materials is substantiated by the nature of the wood and the work performed, as well as by the author's plan and conceptual idea. The article discusses the key methods of wood finishing in the process of creating wooden sculptures. The author lists the main types of wood finishing, as well as the original techniques. It is noted that there are various technologies for giving a wood surface a different color. Description is given to such methods as fire-treatment and waxing of wooden surface; as well as to the original techniques of treating wood damaged by the bark beetle or exposed to fire. It is claimed that proper firing gives wood strength and resistance, protecting it from various influences and significantly extending its durability. Special attention is given to the wood ash treatment, and how this ancient technology can be applied in modern wooden sculpture. The recommendations are given for proper selection of applicators that contribute to quality dyeing of wooden surfaces.

An Alternative in Determining the Best Wood for Guitar Materials Using MOORA Method

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 materials used as guitar materials are rotten quickly and are dull in terms of color. Based on these problems, a solution is sought using the Multi Objective Optimization on the basis of Ratio Analysis (MOORA) decision support system method, and is assisted by experts in determining the right criteria related to determining the best wood used in making guitar materials, after a long time discussing the correct criteria were found based on the problem, in the form of criteria for wood strength, wood grain, texture, and wood weight. All of these criteria are then processed using the MOORA decision support system method. After processing, the best results are obtained. The right wood for guitar making is ebony with 23.6831 results occupying the first rank. Proving the results of the MOORA decision support system method, a questionnaire was carried out directly to several guitar makers with a total of 14 people, resulting in an accuracy of 85.71% which means that it has significant verification, that ebony wood is best used as a guitar-making material

Modified geopolymer-based wood adhesive using waterborne polyurethane

Geopolymer binders show great potential in the application of eco-friendly wood composite adhesives. The applicability of organic-inorganic hybrid-reinforced geopolymer composites as plywood binder was investigated. In this study, a geopolymer-based wood adhesive was fabricated by mixing a matrix-geopolymeric slurry; a toughening agent, waterborne polyurethane; and a silane coupling agent, that served as the covalent “bridge” between the waterborne polyurethane with a geopolymer matrix. The results showed that the waterborne polyurethane exhibited excellent compatibility with the geopolymer and served as a flexibilizer, which transformed the matrix from a microfractured structure to a denser morphology. Moreover, the shear strength of bonded plywood and the morphology of the fracture surface after the tensile measurement were measured. The resulting geopolymer/wood interface was well bonded, and the interfacial bonding strength was higher than the wood strength matrix after modification. The introduction of waterborne polyurethane and silane coupling agent improved the water resistance of the composites and increased the wet shear strength of plywood from 0 MPa to 0.35 MPa. Notably, a weak wood/alkali interface was formed under alkaline conditions due to the strong diffusion of alkali metal ions between the interfaces.

Sifat Dasar Kayu Ganitri (Elaeocarpus sphaericus (Gaertn.) K. Schum.) dari Sukabumi dan Potensi Penggunaannya

Ganitri (Elaeocarpus sphaericus (Gaertn.) K. Schum.) adalah pohon cepat tumbuh yang banyak ditemukan di Sukabumi. Kayu ini tumbuh di hampir semua wilayah Indonesia. Tulisan ini menyajikan hasil pengujian sifat dasar (struktur anatomi, kimia, sifat fisis dan mekanis) kayu ganitri yang diambil dari hutan rakyat di daerah Sukabumi. Tujuan penelitian adalah untuk mengetahui potensi penggunan kayu ganitri berdasarkan sifat dasar dan penggunaan kayu oleh masyarakat sekitar. Hasil penelitian menunjukkan bahwa kayu ganitri memiliki kayu teras berwarna kuning dan kayu gubal berwarna putih. Corak kayu polos dan tekstur halus. Arah serat lurus sampai berpadu, kayu lunak, tidak mengkilap, dan tidak berbau. Berdasarkan nilai dimensi serat dan nilai turunannya, kayu ganitri termasuk ke dalam Kelas Mutu II. Kayu ganitri memiliki kadar holoselulosa dan selulosa yang tinggi (70,70% dan 54,58%), kadar sedang untuk lignin 21,60%, ekstraktif alkohol-benzena 3,47%, dan kadar abu 0,81%. Dengan berat jenis (BJ) kering udara 0,35 kayu ganitri termasuk ke dalam Kelas Kuat IV. Kayu tersebut disarankan untuk digunakan sebagai bahan bangunan konstruksi ringan, perkakas, furnitur, kayu lapis, papan sambung dan produk panel. Basic Properties of Ganitri Wood (Elaeocarpus sphaericus (Gaertn.) K. Schum from Sukabumi and Its Potential UsesAbsractGanitri (Elaeocarpus sphaericus (Gaertn.) K. Schum.) is a fastgrowing tree that is widely found in Sukabumi, West Java. It grows in all part of Indonesia. A research was carried out to investigate basic properties (anatomical, physical, mechanical, and chemical) of ganitri wood from the community forest of Sukabumi. The purpose of this study was to determine the potential use of ganitri wood based on its basic properties and local utilization. The results showed that the color of ganitri sapwood was white , and it was not clearly demarcated from the yellow, with fewer figure patterns. The texture was fine with straight to interlocked grain. The wood was soft, not lustrous, and no special odor. Based on the fibre dimensions and derivative values, the quality of ganitri wood fell in Class II as a raw material for pulp and paper. Ganitri had high holocellulose and cellulose levels (70.70% and 54.58%), moderate level in lignin (21.60%), and it contained 3.47% extractive soluble in alcohol-benzene, and 0.81% ash. Based on its air dry specific gravity (0,35), ganitri wood could be classified into wood Strength Class IV. The potential uses of ganitri are for lightweight construction material, tools, furniture, plywood, connecting boards, and other panel products.