The Blue Stain Attack and Its Effect on The Mechanical Properties of Five Light-Colour Woods

The processing of light-color wood often has problems due to blue stain, which can reduce the quality and economic value of the wood. This research aimed to evaluate the intensity of blue stain attack on five light-color woods and the effect on their mechanical properties. Pine, rubber, jabon, sengon, and gmelina logs with an average diameter of 30 cm were turned into 3 cm thickness disc samples for staining fungal test; 2 cm × 2 cm × 30 cm and 3 cm × 3 cm × 6 cm samples for bending and hardness tests respectively. All the samples were exposed to the environment above ground on a rack for six weeks. The results showed that the highest intensity of blue stain attack was found in pine wood (84%), followed by rubber wood (80%), jabon wood (65%), sengon wood (36%), and gmelina wood (27%). The mechanical properties (modulus of elasticity, modulus of rupture, and hardness) of all wood-attacked blue stains did not significantly differ from their control samples

Improving Students’ Scientific Literacy Skills Using Inquiry- Based E-Comic At The Tenth Grader In Lampung Province

This study aims to determine the effect of inquiry-based e-comic media on students' scientific literacy abilities and to determine students' responses to inquiry-based e-comic. This type of research is a quasi experiment; The sample in the study was taken using the cluster random sampling technique; The research data was taken through the pretest and posttest to see the increase in scientific literacy skills after the learning process while the use of a questionnaire in the experimental class was used to find out students' responses to e-comic media; The results showed that there was a significant effect of the use of inquiry-based e-comic media on students' scientific literacy skills with a significance value of the independent sample t-test of 0.000 or less than 0.05; The results of the questionnaire on student responses to inquiry-based e-comic media obtained an average percentage of 86% in the very good category ABSTRAK: Penelitian ini bertujuan untuk mengetahui pengaruh media ecomic berbasis inquiry terhadap kemampuan literasi sains peserta didik serta mengetahui tanggapan peserta didik terhadap e-comic berbasis inquiry. Jenis penelitian ini adalah quasi eksperimen; Sampel dalam penelitian diambil menggunakan teknik Cluster random sampling; Data penelitian diambil melalui pretest dan posttest untuk melihat peningkatan kemampuan literasi sains setelah proses pembelajaran sedangkan penggunaan angket di kelas eksperimen digunakan untuk mengetahui tanggapan peserta didik terhadap media e-comic; Hasil penelitian menunjukkan terdapat pengaruh yang signifikan penggunaan media ecomic berbasis inquiry terhadap kemampuan literasi sains peserta didik dengan nilai signifikansi uji independent sample t-test 0,000 atau kurang dari 0,05; Hasil angket tanggapan peserta didik terhadap media media ecomic berbasis inquiry diperoleh rata-rata persentase 86% dengan kategori sangat baik

Karakteristik dan Sifat-Sifat Dasar Kayu Jati Unggul Umur 4 dan 5 Tahun Asal Jawa Barat

Anatomical characteristics, fiber morphology, microfibril angle, specific gravity and wood density, dimensional stabilization, modulus of rupture (MOR), modulus of elasticity (MOE), hardness and natural durability of superior teakwood from West Java were studied comprehensively in order to find out their best quality improvement technique. It was showed that quality improvement technique has to be employed since characteristics and properties of the superior teakwood studied are inferior compared to those of the older teakwood. In general wood strength, wood durability, wood stability and wood figure were lower compared to those of the conventional teakwood

Karakteristik dan Sifat-Sifat Dasar Kayu Jati Unggul Umur 4 dan 5 Tahun Asal Jawa Barat

Anatomical characteristics, fiber morphology, microfibril angle, specific gravity and wood density, dimensional stabilization, modulus of rupture (MOR), modulus of elasticity (MOE), hardness and natural durability of superior teakwood from West Java were studied comprehensively in order to find out their best quality improvement technique. It was showed that quality improvement technique has to be employed since characteristics and properties of the superior teakwood studied are inferior compared to those of the older teakwood. In general wood strength, wood durability, wood stability and wood figure were lower compared to those of the conventional teakwood

Characterization of thermally modified short and long rotation teaks and the effects on coatings performance

Many wood processing industries use short rotation teak, which has lower quality especially in durability and dimensional stability. Heat treatment is an eco-friendly method to improve dimensional stability and durability of wood. The objectives of the study were to investigate the effects of thermal modification on chemical composition, colour, dimensional stability and durability as well as coating’s performance after accelerated weathering of short and long rotation teak for exterior utilization. In this study, the samples were heated in oven at 220 °C for 20 h under nitrogen atmosphere. Results showed that independently of growth conditions teak woods underwent hemicelluloses degradation and an increase of lignin content after heat treatment. Extractives contents were lower in short rotation than in long rotation teak, and decreased in all cases after heat treatments. Dimensional stability was considerably improved as indicated by anti-swelling efficiency values of 64.9% and 58.9% for short and long rotation teak, respectively. Heated teak woods were more resistant against Trametes versicolor and the durability of short-rotation teak increased from moderate to very durable. Coatings on heat treated teaks had better bonding quality and better photo-stability when compared to unheated. Heated short rotation teak could be considered for exterior application

Sifat Fisis Dan Mekanis Kayu Dari Hutan Rakyat Dalam Uji Biodeteriorasi Di Beberapa Daerah Bagian Barat Pulau Jawa

Abstrak Penggunaan kayu dari hutan rakyat untuk bangunan dan furnitur semakin banyak. Oleh karena itu, penelitian ini bertujuan untuk mengevaluasi sifat fisik dan mekanik kayu setelah uji biodeteriorasi alami tanpa menyentuh tanah di empat kota berbeda di bagian Barat Pulau Jawa. Kayu yang digunakan dalam penelitian ini sengon, nangka, mangium, mahoni dan kamper. Uji biodeteriorasi kayu tidak menyentuh tanah dilakukan di Bogor, Tanjung Priok, Lembang, dan Serang. Sifat fisik dan mekanik kayu diuji setelah uji lapang biodeteriorasi tersebut. Hasil penelitian menunjukkan bahwa penurunan berat kayu, berat jenis, modulus elastisitas dan modulus patah dari contoh uji kayu bervariasi di antara berbagai jenis kayu dan tempat uji. Degradasi tertinggi terjadi pada kayu sengon, sedangkan degradasi kayu mangium dan mahoni lebih tinggi daripada kayu nangka dan kamper. Sifat fisik dan mekanik kayu yang diuji di Bogor yang bercurah hujan tinggi dan bersuhu hangat lebih buruk daripada kayu yang diuji di tempat -tempat lainnya.Abstract The use of woods from community forests for building and furniture are increasing. Therefore, this study aimed to evaluate the physical and mechanical properties of woods exposed to above ground biodeterioration test in four different cities in the West part of Java Island. The woods used in this study were sengon, jackfruit, mangium, mahogany and camphor. Above ground biodeterioration test of the woods were conducted in Bogor, Tanjung Priok, Lembang, and Serang. The physical and mechanical properties of the woods were tested after the biodeterioration test. The results showed that the weight loss, specific gravity, modulus of elasticity and modulus of rupture of the woods were different among wood species and exposure palces. The highest degradation occurred in sengon wood, while degradation of mangium and mahagoni woods were higher than that of nangka and kamper woods. The physical and mechanical properties of the woods exposed in Bogor with high rainfall and warm temperature were worse than the woods exposed in the other places

Sudut Kontak dan Keterbasahan Dinamis Kayu Samama pada Berbagai Pengerjaan Kayu

AbstrakSudut kontak dan keterbasahan dinamis penting diketahui untuk menganalisis keteguhan rekat. Penelitian ini bertujuan mengetahui sudut kontak dan keterbasahan dinamis kayu samama pada berbagai pengerjaan kayu. Metode yang digunakan adalah meneteskan air destilata, perekat UF dan isosianat dengan ukuran tertentu pada permukaan kayu hasil gergaji dan hasil mesin kupas. Permukaan kayu gergajian yang ditetesi oleh cairan adalah permukaan radial, tangensial dan permukaan yang membentuk sudut 45° antara radial dan tangensial. Sementara itu permukaan finir hasil pengupasan adalah permukaan tight dan loose. Kayu gergajian maupun finir yang dianalisis pada penelitian ini, keduanya diambil dari bagian juvenil dan dewasa. Keterbasahan dinamis dianalisis menggunakan model SD. Hasil penelitian menunjukkan bahwa porositas permukaan bahan berpengaruh terhadap keterbasahan kayu samama oleh cairan. Permukaan tangensial memiliki sifat yang lebih mudah mengalami keterbasahan dibandingkan dengan permukaan radial maupun TR (permukaan antara radial dan tangensial) sementara bagian juvenil memiliki tingkat keterbasahan lebih baik dibandingkan dewasanya. Finir samama memiliki tingkat keterbasahan setara dengan permukaan TR kayu samama dimana bagian juvenil finir memiliki laju keterbasahan yang lebih baik dibandingkan dengan finir dewasa. Disamping itu, bagian loose finir lebih cepat terbasahi oleh cairan dibandingkan bagian tight.AbstractContact angle and dynamic wettability is important in determining bonding strength, therefore, this study addressed contact angle and dynamic wettability of samama wood in various woodworking. Method used in the study was by dripping distill water, UF and isocyanate adhesives in particular size on the surface of wood processed by circular saw and peeling machine. The surfaces of sawn wood which dripped by those liquids were radial, tangential, and surface which made a 45° angle between radial and tangential. Meanwhile the tested surfaces of peeled-veneer were tight and loose surfaces. Both sawn wood and veneer in this study were taken from juvenile and mature part of the samama wood. Dynamic wettability was analyzed using SD model. The results showed that porosity of the surface significantly affected the wettability of samama wood by liquid. The profile of tangential surface made it had a better wettability than radial and TR (i.e. surface between radial and tangential) surfaces. Meanwhile, juvenile part showed better wettability than the mature one. The samama veneer had equal wettability with TR surface of sawn wood in which the juvenile one showed better wettability than the mature veneer. Further, it was noticed that loose surface of the veneer was wetted faster than the tight one

Natural Durability and Preservative Treatability of Mangium, Manii and Sengon Woods by Cold Soaking and Hot-Cold Soaking Methods

The understanding of the natural durability and preservative treatability of woods from community forests/lands is paramount to prevent biodeterioration of the woods in its utilization. This research was aimed to determine the natural durability of community woods (mangium, manii, and sengon) against subterranean termites (Coptotermes curvignatus) and dry wood termites (Cryptotermes cynocephalus), and to determine their preservative treatability with Diffusol CB applied through cold soaking and hot-cold soaking preservation methods. The results showed that manii and mangium woods were more resistant from subterranean termites and dry wood termites compared to that of sengon wood. The penetration and retension of Diffusol CB by Hot-cold preservation were twofold of that by cold soaking preservation. Penetration and retension of preservative in sengon wood was the highest, more than threefold of those in mangium (the lowest preservative treatability).Keywords: dry wood termite, natural durability, preservative treatability, subterranean termit