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All Journal Jurnal Ilmu Pertanian Indonesia Jurnal Ilmu dan Teknologi Hasil Hutan Jurnal Penelitian Hasil Hutan Jurnal Ilmu dan Teknologi Kayu Tropis Jurnal Penelitian Hasil Hutan International Journal of Recent Technology and Applied Science (IJORTAS) Jurnal Ilmiah STOK Bina Guna Medan Wood Research Journal : Journal of Indonesian Wood Research Society Wood Research Journal : Journal of Indonesian Wood Research Society Jurnal Sylva Lestari Makara Journal of Technology Prosiding University Research Colloquium
I Wayan Darmawan
Departemen Teknologi Hasil Hutan, Fakultas Kehutanan, Institut Pertanian Bogor, Kampus IPB Dramaga, Bogor 16680
Agriculture, Biological Sciences & Forestry Humanities Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Civil Engineering, Building, Construction & Architecture Computer Science & IT Control & Systems Engineering Decision Sciences, Operations Research & Management Earth & Planetary Sciences Education Electrical & Electronics Engineering Energy Engineering Environmental Science Industrial & Manufacturing Engineering Law, Crime, Criminology & Criminal Justice Materials Science & Nanotechnology Mechanical Engineering Medicine & Pharmacology

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Research and Innovations in Products Quality Improvement of Short Rotation Woods for Industry 4.0 Wayan Darmawan
Prosiding University Research Colloquium Proceeding of The 8th University Research Colloquium 2018: Bidang Sosial Ekonomi dan Psikologi
Publisher : Konsorsium Lembaga Penelitian dan Pengabdian kepada Masyarakat Perguruan Tinggi Muhammadiyah 'Aisyiyah (PTMA) Koordinator Wilayah Jawa Tengah - DIY

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (510.442 KB)

Abstract

Juvenile portion of tree stem surrounding the pith is characterized by a progressive change in cell features and wood properties (Panshin and de Zeeuw 1980). In comparison with mature wood, juvenile wood is made of smaller and shorter fibers with thinner walls and larger microfibril angles, lower density, and lower strength properties (Clark et al. 2006; Gryc et al. 2011; Koubaa et al. 2005: Adamopoulus et al. 2007; Evans et al. 2000). It is well known that characteristics of juvenile wood contribute to undesirable solid wood properties. Juvenile wood is not substandard for products such as newsprint and quality printing paper (Zobel 1984). However, it may cause serious problems for quality products, especially veneer or solid wood products. This is due to its low bending strength and dimensional instability upon drying. Juvenile wood of black locust had on average significantly lower static bending strength (MOR, and MOE), dynamic strength, and toughness strength than the mature wood (Adamopoulus et al. 2007). One of the most serious problems in drying and utilization of young plantation grown conifers was warp in the form of twist, crook and bow (Kliger 2001; Johansson and Kliger 2002). One possible means to reduce the negative impact of juvenile wood is to select for an earlier transition age from juvenile to mature wood.
Physical and Mechanical Properties of Oriented Flattened Bamboo Boards from Ater (Gigantochloa atter) and Betung (Dendrocalamus asper) Bamboos Alfira Ramadhani Putri; Nur Alam; Ulfa Adzkia; Yusup Amin; I Wayan Darmawan; Lina Karlinasari
Jurnal Sylva Lestari Vol. 11 No. 1 (2023): January
Publisher : Department of Forestry, Faculty of Agriculture, University of Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jsl.v11i1.614

Abstract

Bamboo-based composite has been used widely for building components and furniture. Oriented flattened bamboo board (OFBB) is a composite board consisting of oriented structure sheets of flattening bamboo. This study aimed to analyze the physical and mechanical properties of the OFBB from ater (Gigantochloa atter) and betung (Dendrocalamus asper) bamboo. A three-layer flattened bamboo board using the isocyanate resin with a density target of 0.6 g/cm3 was applied. The characteristics of raw bamboo, the contact angle of OFBB, and board properties of density, moisture content, thickness swelling, and water absorption, as well as bending, internal bonding (IB), and compressive strength properties were determined to evaluate the quality of the OFBB.  Based on the findings, the thin wall thickness of ater bamboo enhanced the physical and mechanical properties of the OFBB compared to the higher wall thickness of betung bamboo.  Therefore, further development in bamboo composite products with those anatomical properties seems promising. The dimensional stability and bending properties of OFBB from ater bamboo met the quality of first grade of the Canadian Standard for OSB and waferboard, except for the IB strength. Keywords: Bamboo wall thickness, contact angle, Dendrocalamus asper, Gigantochloa atter, oriented flattened bamboo board
Research and Innovations in Products Quality Improvement of Short Rotation Woods for Industry 4.0 Wayan Darmawan
Prosiding University Research Colloquium Proceeding of The 8th University Research Colloquium 2018: Bidang Sosial Ekonomi dan Psikologi
Publisher : Konsorsium Lembaga Penelitian dan Pengabdian kepada Masyarakat Perguruan Tinggi Muhammadiyah 'Aisyiyah (PTMA) Koordinator Wilayah Jawa Tengah - DIY

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Juvenile portion of tree stem surrounding the pith is characterized by a progressive change in cell features and wood properties (Panshin and de Zeeuw 1980). In comparison with mature wood, juvenile wood is made of smaller and shorter fibers with thinner walls and larger microfibril angles, lower density, and lower strength properties (Clark et al. 2006; Gryc et al. 2011; Koubaa et al. 2005: Adamopoulus et al. 2007; Evans et al. 2000). It is well known that characteristics of juvenile wood contribute to undesirable solid wood properties. Juvenile wood is not substandard for products such as newsprint and quality printing paper (Zobel 1984). However, it may cause serious problems for quality products, especially veneer or solid wood products. This is due to its low bending strength and dimensional instability upon drying. Juvenile wood of black locust had on average significantly lower static bending strength (MOR, and MOE), dynamic strength, and toughness strength than the mature wood (Adamopoulus et al. 2007). One of the most serious problems in drying and utilization of young plantation grown conifers was warp in the form of twist, crook and bow (Kliger 2001; Johansson and Kliger 2002). One possible means to reduce the negative impact of juvenile wood is to select for an earlier transition age from juvenile to mature wood.
Impregnation Effect of Synthesized Fe3O4 Nanoparticles on the Jabon Wood’s Physical Properties Rahayu, Istie Sekartining; Ismail, Rohmat; Darmawan, Wayan; Wahyuningtyas, Irma; Prihatini, Esti; Laksono, Gilang Dwi; Khairunissa, Dhiya
International Journal of Recent Technology and Applied Science (IJORTAS) Vol 6 No 2: September 2024
Publisher : Lamintang Education and Training Centre, in collaboration with the International Association of Educators, Scientists, Technologists, and Engineers (IA-ESTE)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.36079/lamintang.ijortas-0602.701

Abstract

This study focused on characterizing synthetic magnetite (Fe3O4-NP) and evaluating the impregnated jabon wood’s physical properties. The co-precipitation method used for the synthesis of Fe3O4-NP, namely by mixing the iron solution (n/n Fe2+:Fe3+=1:2) with the strong base of sodium hydroxide (NaOH) (MG-S) and weak base of ammonium hydroxide (NH4OH) (MG-W) as precursors. The impregnation stage uses parameters of a -0.5 bar vacuum for half an hour and 2 bar pressure for 2 hours with magnetite concentrations of 1; 2.5; 5% w/v in a demineralized water solvent. Scanning electron microscopy-energy dispersive x-ray spectroscopy (SEM-EDX) and Fourier transform infrared spectrometry (FTIR) confirmed the presence of Ferrum content and Fe-O functional group in both Fe3O4-NPs produced. The Fe3O4-NP size was also measured via the X-ray diffraction analysis, namely 34.54 nm for the MG-S and 39.24 nm for the MG-W. Magnetic strength obtained was 7.51 mT for the MG-S and 8.58 mT for the MG-W. The impregnated jabon wood’s physical properties also improved with indications of an increase in wood density, weight percent gain (WPG), bulking effect (BE), anti-swelling efficiency (ASE), and a decrease in water absorption (WA). The results showed the best treatments were MG-S 2.5% and MG-W 5%.
Mikrostruktur dan Karakteristik Permukaan Kayu Pinus Scots (Pinus sylvestris L.) Termodifikasi Gliserol dan Asam Sitrat Tobing, Gabriel; Sofiaturizkiyah, Nurul; Basri, Efrida; Martha, Resa; Rahayu, Istie; Gérardin, Philippe; Darmawan, Wayan
Jurnal Ilmu Pertanian Indonesia Vol. 29 No. 4 (2024): Jurnal Ilmu Pertanian Indonesia
Publisher : Institut Pertanian Bogor

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.18343/jipi.29.4.554

Abstract

Scots pine (Pinus sylvestris L.) wood is one of the most popular timber export products. However, its low durability can reduce the potential and utilization of the wood. Chemical modification is one of the solutions to overcome this drawback. Chemical modification using non-biocide materials such as glycerol and citric acid was carried out to improve the inferior properties of wood. The study aimed to observe the microstructure and evaluate the surface characteristics of glycerol and citric acid-modified scots pine wood. Scots pine wood was modified using glycerol and citric acid with weight percent gain (WPG) values of 20% and 46%. Surface characteristics were measured, including surface roughness, surface free energy (SFE), wettability, and bonding quality. The results show that chemical modification using glycerol and citric acid resulted in the structure of the pine wood being more filled and denser. The modification could also reduce the roughness of the wood surface, resulting in decreased SFE value, increased contact angle, and decreased wettability on the wood surface. It might cause a decrease in the bonding quality because the wood did not have the strength to mechanically lock with the paint. Glycerol and citric acid modified-scots pine wood can be considered for exterior application. Keywords: citric acid, glycerol, microstructure, scots pine, surface characteristics
Efektifitas Peran Orang Tua Terhadap Minat Siswa Mengikuti Ekstrakurikuler Pencak Silat SD Negeri 74 Palembang Wayan Darmawan; Bayu Iswana; Bambang Hermansah
Jurnal Ilmiah STOK Bina Guna Medan Vol 13 No 2 (2025): JURNAL ILMIAH STOK BINA GUNA MEDAN
Publisher : Sekolah Tinggi Olahraga dan Kesehatan Bina Guna

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55081/jsbg.v13i2.4085

Abstract

Penelitian ini bertujuan untuk mengetahui Efektifitas Peran Orang Tua Terhadap Minat Siswa Mengikuti Ekstrakurikuler Pencak Silat SD Negeri 74 Palembang. Metode yang digunakan yaitu deskriptif kuantitatif dengan desain penelitian survey. Sampel dalam penelitian ini menggunakan sampel Nonprobability Sampling jenis Purposive Sampling yang berjumlah 60 orang terdiri dari 30 siswa dan 30 orang tua. Teknik pengambilan data menggunakan kuisioner dan dokumentasi. Instrumen yang digunakan dalam mengetahui Efektifitas peran orang tua terhadap minat siswa mengikuti ekstrakurikuler pencak silat berupa angket. Teknik analisis data dalam penelitian ini menggunakan uji Analisis Korelasi Person dan Teknik analisis regresi linier sederhana berbantuan SPSS 25. Hasil dari penelitian menunjukkan bahwa Orang tua di SD Negeri 74 Palembang memiliki peran yang cukup signifikan dalam mendukung minat siswa terhadap ekstrakurikuler pencak silat. Dilihat dari Nilai Pearson Correlation sebesar 0,236 menunjukkan adanya hubungan positif antara peran orang tua dengan minat siswa dan konstanta (Intercept) memiliki nilai signifikansi 0.002 (<0.05), sehingga secara statistik konstanta ini signifikan.
Co-Authors A.A. Ketut Agung Cahyawan W Abigael Kabe Adi Santoso Adi Santoso Alfira Ramadhani Putri Andi T. Lestari Bambang Hermansah Bayu Iswana Deded Sarip Nawawi Devi Armilasari Dodi Nandika Dumasari Dumasari, Dumasari Efrida Basri Fauzan Fahrussiam Gérardin, Philippe Hiroshi Usuki I Kentut Pandit Ignasia Maria Sulastiningsih Imam Santosa Imam Wahyudi Indrawan, Imam Wahyudi Irsan ALIPRAJA Ismail, Rohmat Istie Rahayu Itan Iskova PURBA Jamaludin Malik Jamaludin Malik Khairunissa, Dhiya Laksono, Gilang Dwi Lina Karlinasari Lusita WARDANI Lusita WARDANI Lya Rochmawati Martha, Resa Masahiro Yoshinobu Muh. Yusram Massijaya Muh. Yusram Massijaya Muh. Yusram Massijaya Muh. Yusram Massijaya Muhamad Yusram Massijaya Muhammad Y Massijaya Naoki Okano Naresworo Nugroho Nur Alam Prihatini, Esti Remy Marchal Rita Kartika Sari Rumanintya Lisaria Putri Sarah Augustina Sarah Augustina Shuhou Koseki Silmi Mariya Sofiaturizkiyah, Nurul Sulistyani Budiningsih Surdiding Ruhendi Surdiding RUHENDI Surdiding Ruhendi Taiyo Okada Tobing, Gabriel Ulfa Adzkia Wahyuningtyas, Irma Widyana LUZA Yoichi Kojima Yusuf Sudo Hadi Yusup Amin