evalina herawati | University of Sumatera Utara (original) (raw)
Papers by evalina herawati
Polymers
The suitability of bamboo’s basic characteristics is very important for more specific purposes, s... more The suitability of bamboo’s basic characteristics is very important for more specific purposes, such as composite raw materials. Anatomical, physical, mechanical, and chemical characteristics are some of bamboo’s fundamental characteristics. This study analyses the basic properties, such as physical, mechanical, and chemical properties of bamboo from the Forest Area with Special Purpose (FASP) Pondok Buluh Sumatera Island, Indonesia (I); analyses the relationship between the properties of each type of bamboo (II); and chooses the type of bamboo with the best properties that have the potential to be applied to composite materials, such as laminated bamboo (III). This study used materials consisting of six species of bamboo from the FASP Pondok Buluh. The manufacture of physical and mechanical test samples refers to the ISO 22157 standard, 2004, while the chemical properties test refers to the TAPPI 1999 standard. The chemical, physical, and mechanical properties of bamboo vary widely...
Glued-laminated (glulam) beams is one of engineered wood products used for structural application... more Glued-laminated (glulam) beams is one of engineered wood products used for structural applications. The objective of this research is to evaluate characteristics of glulam beams made from Acacia mangium Willd. Laminations used were 2, 4, 6, 8 and 12 cm in widthnesses, 2 cm in thickness and 260 cm in length. Each lamination was graded using Machine Stress Grading (namely by Panter or plank sorter) to determine the modulus of elasticity (MOE) value. The glulam beams was 6 cm x 12 cm in five types of cross-section which arranged by various widths and those MOE of laminations. Glulam beams were bonded by water based polymer isocyanate (WBPI) using 280 g/m2 double glue spread. The research results showed that glulam beams made from A. mangium Willd. fulfilled the JAS 234:2003 standard as on following properties: moisture content, MOE, MOR, shear strength and immersion delamination test. However, performance of glulam was unsatisfactory in wood failure ratio and boiling water so...
Glued-laminated (glulam) beams is one of engineered wood products used for structural application... more Glued-laminated (glulam) beams is one of engineered wood products used for structural applications. The objective of this research is to evaluate characteristics of glulam beams made from Acacia mangium Willd. Laminations used were 2, 4, 6, 8 and 12 cm in widthnesses, 2 cm in thickness and 260 cm in length. Each lamination was graded using Machine Stress Grading (namely by Panter or plank sorter) to determine the modulus of elasticity (MOE) value. The glulam beams was 6 cm x 12 cm in five types of cross-section which arranged by various widths and those MOE of laminations. Glulam beams were bonded by water based polymer isocyanate (WBPI) using 280 g/m 2 double glue spread. The research results showed that glulam beams made from A. mangium Willd. fulfilled the JAS 234:2003 standard as on following properties: moisture content, MOE, MOR, shear strength and immersion delamination test. However, performance of glulam was unsatisfactory in wood failure ratio and boiling water soak delamination test.
Polymers
The use of natural fibers or particles as alternative raw materials for particleboard production ... more The use of natural fibers or particles as alternative raw materials for particleboard production is essential due to the shrinking forest area. Currently, dung waste from the Sumatran elephant (Elephas maximus sumatranus) is being used as a raw material for particleboard due to its high fiber content. Although the product still has inferior mechanical and physical characteristics, it can be improved by layering bamboo. Therefore, this study aimed to enhance the mechanical and physical qualities of elephant dung particleboard by adding layers of bamboo. The particleboard constructed had three layers; namely, the face and back in the form of a bamboo layers, as well as the core, which was in the form of elephant dung. The elephant dung was evenly mixed with isocyanate adhesive using a spray gun, and the bamboo layers were coated with adhesive on one side of the surface. The sample was subjected to a hot press at a temperature of 150 °C and 30 kg/cm2 pressure for 10 min. Generally, JIS...
Polymers
Sumatran elephants (Elephas maximus sumatranus) are the world’s largest living land mammals. The ... more Sumatran elephants (Elephas maximus sumatranus) are the world’s largest living land mammals. The elephant’s digestive system can only absorb 40% of the nutrients in digested feed, and the remainder is excreted as dung. Elephant dung waste can be used as a particleboard material due to its high fiber content. The objectives of this study are: (i) to prepare elephant dung waste as raw material for particleboard, (ii) to improve elephant dung particleboard’s physical and mechanical properties using wood shavings, and (iii) to study the influence of several parameters on the physical and mechanical properties of particleboard. The particleboard dimensions and density were set at 20 cm × 20 cm × 1 cm and 0.8 g/cm3, respectively. The mixture ratio of elephant dung and wood shavings was 100/0, 90/10, 80/20, 70/30, 60/40, and 50/50 (% w/w). This mixture ratio of particles was sprayed with 7% isocyanate adhesive. The pressing at a pressure of 30 kg/cm2 for 5 min and 160 °C was used in this s...
Abstrak Baut merupakan salah satu jenis alat sambung mekanis atau pengencang yang banyak digunaka... more Abstrak Baut merupakan salah satu jenis alat sambung mekanis atau pengencang yang banyak digunakan dalam sambungan kayu. Penelitian ini bertujuan untuk menentukan kekuatan leleh lentur (F yb ) dari tiga ukuran diameter baut besi yang umum digunakan untuk sambungan kayu dan satu ukuran diameter baut baja sebagai pembanding. Spesifikasi baut yang digunakan dilihat dari dimensi dan komposisi penyusunnya. Nilai F yb baut diperoleh dari pengujian momen leleh lentur dengan mengacu pada standar ASTM F1575. Hasil pengujian menunjukkan baut besi yang digunakan berasal dari bahan baja karbon rendah sedangkan baut baja berasal dari bahan baja karbon sedang. Nilai F yb baut baja lebih tinggi dibandingkan baut besi. Nilai F yb baut besi diameter 1/2 inci berbeda nyata dengan nilai baut diameter 5/8 dan 3/4 inci. Nilai F yb ketiga diamater baut berada di atas nilai F yb baut yang tercantum dalam SNI 7973:2013 tentang Spesifikasi desain untuk konstruksi kayu. Abstract Bolt is one of the mecha...
IOP Conference Series: Earth and Environmental Science, 2019
The reference lateral design value is the basic load capacity for a fastener subjected to a later... more The reference lateral design value is the basic load capacity for a fastener subjected to a lateral shear load. The design value is a consideration in designing a wooden connection. The main objective of this research was to determine the reference design value for a single bolt connection using Merbau wood. In this study, the experimental reference lateral design values were determined from the load-deformation curve with a 5% diameter offset method based on connection testing which refers to ASTM D5652 standard test methods for bolted connections in wood and wood-based products. Meanwhile, the prediction reference lateral design values were determined based on the formulas in the national design specification for wood construction. The wood used was Merbau (Intsia spp) using three bolt diameters (1/2, 5/8 and 3/4 in) and several wood thickness combinations. The results showed that the experimental design reference values ranged from 475 kg to 887 kg. The reference lateral design v...
MAKARA of Technology Series, 2012
Penelitian pemanfaatan sludge sebagai bahan baku pembuatan papan serat berkerapatan sedang atau m... more Penelitian pemanfaatan sludge sebagai bahan baku pembuatan papan serat berkerapatan sedang atau medium density fibreboard (MDF) berguna untuk menciptakan nilai tambah dari sludge. Tujuan dari penelitian ini adalah mengevaluasi sifat fisis, mekanik, dan ketahanan MDF dari sludge terasetilasi dengan 4 macam konsentrasi asetat anhidrida (0%, 3%, 5% dan 7%) dengan 3 kali ulangan. Pembuatan MDF dilakukan dengan proses kering. Setelah bahan baku dicampur perekat, dilakukan pengempaan dengan menggunakan kempa panas dengan suhu 170 o C dan tekanan 45 Pa selama 25 menit. Ukuran papan yang akan dibuat adalah 25 cm x 20 cm x 1 cm dengan kerapatan 0,8 g/cm 3. Selanjutnya dilakukan pengujian sifat fisik (kerapatan, kadar air, daya serap air, pengembangan tebal) dan mekanik (keteguhan lentur, keteguhan patah, keteguhan rekat, kuat pegang sekrup) terhadap MDF yang dihasilkan yang mengacu pada JIS A 5905-2003 dan pengujian ketahanan mengacu pada SNI 01-7207-2006. Keseluruhan sifat fisik MDF memenuhi standar JIS A 5905-2003. Pemberian asetat anhidrida menurunkan nilai kadar air MDF yang dihasilkan. Hasil pengujian sifat mekanik seluruhnya tidak memenuhi standar yang diacu. Hal tersebut dipengaruhi oleh kalsium karbonat dalam sludge yang menghambat ikatan antar serat sludge. Hasil pengujian keawetan MDF termasuk kedalam kelas I, yaitu sangat tahan terhadap rayap.
International Wood Products Journal, 2017
ABSTRACT Bearing strength largely affects the performance of wood connections. This study, determ... more ABSTRACT Bearing strength largely affects the performance of wood connections. This study, determines the bearing strengths of six Indonesian tropical hardwoods with different specific gravities (ranging from 0.43 to 0.84) by half-hole testing. The results for three bolt diameters were compared to the bearing strengths in the Indonesian National Standard (SNI) and the National Design Specification (NDS) for Wood Construction. Next, the bolt-bearing strengths were related to the specific gravities and mechanical properties of the woods. With increasing specific gravity, the bearing strength increased from 26 to 70 MPa. The experimentally obtained bearing strengths of light and heavy red meranti, mersawa, kapur and bangkirai woods were 3–15% and 11–23% lower than the SNI and NDS values, respectively. In contrast, the experimental result for merbau was 23 and 11% higher than the SNI and NDS values, respectively. The bearing strength most closely approached the compression strength parallel to the grain.
Kayu telah digunakan selama ribuan tahun sebagai bahan konstruksi untuk tempat tinggal, kapal dan... more Kayu telah digunakan selama ribuan tahun sebagai bahan konstruksi untuk tempat tinggal, kapal dan jembatan. Ketersediaan dan kemudahan dalam pengerjaannya pada awalnya telah membuat kayu menjadi pilihan yang logis untuk bahan konstruksi. Belakangan, pilihan ini juga disebabkan oleh biayanya yang lebih rendah dan rasio kekuatan terhadap berat yang tinggi dibandingkan dengan bahan dari logam dan semen (Falk et al., 1990). Kayu merupakan bahan yang memiliki keragaman dalam sifat-sifatnya, yang melekat secara inherent. Kayu dikenal sebagai bahan yang bersifat ortotropis. Sifat-sifat struktural kayu tidak hanya bergantung pada arah orientasinya ketika dipotong dari bentuk log tetapi juga pada distribusi, ukuran
Journal of Biological Sciences, 2010
ABSTRACT This study presents properties test results of glued-laminated (glulam) beams made from ... more ABSTRACT This study presents properties test results of glued-laminated (glulam) beams made from two fast growing tree species, namely African wood ( Maesopsis eminii ) and mangium ( Acacia mangium ) using water based polymer isocyanate (WBPI) as a binder. Laminations were used consist of 2, 4, 6, 8 and 12 cm in widthnesses, 2 cm in thickness and 260 cm in length. Each lamination was graded using Machine Stress Grading (namely by Panter or plank sorter) to determine its Modulus of Elasticity (MOE). Cross-section of five types of glulam beams was 6x12 cm, arranged of various widths and based on MOE of laminations. The study results describe that glulam beams made from mangium showed better performance compared to those of African wood based on values of MOE and Modulus of Rupture (MOR). In general, results showed that almost all of glulam beams types of both wood species fulfill the JAS 234:2003 standard in moisture content, MOE, MOR, shear strength and immersion delamination test. However, performance of glulam beams was unsatisfactory in wood failure ratio and boiling water soak delamination test.
Polymers
The suitability of bamboo’s basic characteristics is very important for more specific purposes, s... more The suitability of bamboo’s basic characteristics is very important for more specific purposes, such as composite raw materials. Anatomical, physical, mechanical, and chemical characteristics are some of bamboo’s fundamental characteristics. This study analyses the basic properties, such as physical, mechanical, and chemical properties of bamboo from the Forest Area with Special Purpose (FASP) Pondok Buluh Sumatera Island, Indonesia (I); analyses the relationship between the properties of each type of bamboo (II); and chooses the type of bamboo with the best properties that have the potential to be applied to composite materials, such as laminated bamboo (III). This study used materials consisting of six species of bamboo from the FASP Pondok Buluh. The manufacture of physical and mechanical test samples refers to the ISO 22157 standard, 2004, while the chemical properties test refers to the TAPPI 1999 standard. The chemical, physical, and mechanical properties of bamboo vary widely...
Glued-laminated (glulam) beams is one of engineered wood products used for structural application... more Glued-laminated (glulam) beams is one of engineered wood products used for structural applications. The objective of this research is to evaluate characteristics of glulam beams made from Acacia mangium Willd. Laminations used were 2, 4, 6, 8 and 12 cm in widthnesses, 2 cm in thickness and 260 cm in length. Each lamination was graded using Machine Stress Grading (namely by Panter or plank sorter) to determine the modulus of elasticity (MOE) value. The glulam beams was 6 cm x 12 cm in five types of cross-section which arranged by various widths and those MOE of laminations. Glulam beams were bonded by water based polymer isocyanate (WBPI) using 280 g/m2 double glue spread. The research results showed that glulam beams made from A. mangium Willd. fulfilled the JAS 234:2003 standard as on following properties: moisture content, MOE, MOR, shear strength and immersion delamination test. However, performance of glulam was unsatisfactory in wood failure ratio and boiling water so...
Glued-laminated (glulam) beams is one of engineered wood products used for structural application... more Glued-laminated (glulam) beams is one of engineered wood products used for structural applications. The objective of this research is to evaluate characteristics of glulam beams made from Acacia mangium Willd. Laminations used were 2, 4, 6, 8 and 12 cm in widthnesses, 2 cm in thickness and 260 cm in length. Each lamination was graded using Machine Stress Grading (namely by Panter or plank sorter) to determine the modulus of elasticity (MOE) value. The glulam beams was 6 cm x 12 cm in five types of cross-section which arranged by various widths and those MOE of laminations. Glulam beams were bonded by water based polymer isocyanate (WBPI) using 280 g/m 2 double glue spread. The research results showed that glulam beams made from A. mangium Willd. fulfilled the JAS 234:2003 standard as on following properties: moisture content, MOE, MOR, shear strength and immersion delamination test. However, performance of glulam was unsatisfactory in wood failure ratio and boiling water soak delamination test.
Polymers
The use of natural fibers or particles as alternative raw materials for particleboard production ... more The use of natural fibers or particles as alternative raw materials for particleboard production is essential due to the shrinking forest area. Currently, dung waste from the Sumatran elephant (Elephas maximus sumatranus) is being used as a raw material for particleboard due to its high fiber content. Although the product still has inferior mechanical and physical characteristics, it can be improved by layering bamboo. Therefore, this study aimed to enhance the mechanical and physical qualities of elephant dung particleboard by adding layers of bamboo. The particleboard constructed had three layers; namely, the face and back in the form of a bamboo layers, as well as the core, which was in the form of elephant dung. The elephant dung was evenly mixed with isocyanate adhesive using a spray gun, and the bamboo layers were coated with adhesive on one side of the surface. The sample was subjected to a hot press at a temperature of 150 °C and 30 kg/cm2 pressure for 10 min. Generally, JIS...
Polymers
Sumatran elephants (Elephas maximus sumatranus) are the world’s largest living land mammals. The ... more Sumatran elephants (Elephas maximus sumatranus) are the world’s largest living land mammals. The elephant’s digestive system can only absorb 40% of the nutrients in digested feed, and the remainder is excreted as dung. Elephant dung waste can be used as a particleboard material due to its high fiber content. The objectives of this study are: (i) to prepare elephant dung waste as raw material for particleboard, (ii) to improve elephant dung particleboard’s physical and mechanical properties using wood shavings, and (iii) to study the influence of several parameters on the physical and mechanical properties of particleboard. The particleboard dimensions and density were set at 20 cm × 20 cm × 1 cm and 0.8 g/cm3, respectively. The mixture ratio of elephant dung and wood shavings was 100/0, 90/10, 80/20, 70/30, 60/40, and 50/50 (% w/w). This mixture ratio of particles was sprayed with 7% isocyanate adhesive. The pressing at a pressure of 30 kg/cm2 for 5 min and 160 °C was used in this s...
Abstrak Baut merupakan salah satu jenis alat sambung mekanis atau pengencang yang banyak digunaka... more Abstrak Baut merupakan salah satu jenis alat sambung mekanis atau pengencang yang banyak digunakan dalam sambungan kayu. Penelitian ini bertujuan untuk menentukan kekuatan leleh lentur (F yb ) dari tiga ukuran diameter baut besi yang umum digunakan untuk sambungan kayu dan satu ukuran diameter baut baja sebagai pembanding. Spesifikasi baut yang digunakan dilihat dari dimensi dan komposisi penyusunnya. Nilai F yb baut diperoleh dari pengujian momen leleh lentur dengan mengacu pada standar ASTM F1575. Hasil pengujian menunjukkan baut besi yang digunakan berasal dari bahan baja karbon rendah sedangkan baut baja berasal dari bahan baja karbon sedang. Nilai F yb baut baja lebih tinggi dibandingkan baut besi. Nilai F yb baut besi diameter 1/2 inci berbeda nyata dengan nilai baut diameter 5/8 dan 3/4 inci. Nilai F yb ketiga diamater baut berada di atas nilai F yb baut yang tercantum dalam SNI 7973:2013 tentang Spesifikasi desain untuk konstruksi kayu. Abstract Bolt is one of the mecha...
IOP Conference Series: Earth and Environmental Science, 2019
The reference lateral design value is the basic load capacity for a fastener subjected to a later... more The reference lateral design value is the basic load capacity for a fastener subjected to a lateral shear load. The design value is a consideration in designing a wooden connection. The main objective of this research was to determine the reference design value for a single bolt connection using Merbau wood. In this study, the experimental reference lateral design values were determined from the load-deformation curve with a 5% diameter offset method based on connection testing which refers to ASTM D5652 standard test methods for bolted connections in wood and wood-based products. Meanwhile, the prediction reference lateral design values were determined based on the formulas in the national design specification for wood construction. The wood used was Merbau (Intsia spp) using three bolt diameters (1/2, 5/8 and 3/4 in) and several wood thickness combinations. The results showed that the experimental design reference values ranged from 475 kg to 887 kg. The reference lateral design v...
MAKARA of Technology Series, 2012
Penelitian pemanfaatan sludge sebagai bahan baku pembuatan papan serat berkerapatan sedang atau m... more Penelitian pemanfaatan sludge sebagai bahan baku pembuatan papan serat berkerapatan sedang atau medium density fibreboard (MDF) berguna untuk menciptakan nilai tambah dari sludge. Tujuan dari penelitian ini adalah mengevaluasi sifat fisis, mekanik, dan ketahanan MDF dari sludge terasetilasi dengan 4 macam konsentrasi asetat anhidrida (0%, 3%, 5% dan 7%) dengan 3 kali ulangan. Pembuatan MDF dilakukan dengan proses kering. Setelah bahan baku dicampur perekat, dilakukan pengempaan dengan menggunakan kempa panas dengan suhu 170 o C dan tekanan 45 Pa selama 25 menit. Ukuran papan yang akan dibuat adalah 25 cm x 20 cm x 1 cm dengan kerapatan 0,8 g/cm 3. Selanjutnya dilakukan pengujian sifat fisik (kerapatan, kadar air, daya serap air, pengembangan tebal) dan mekanik (keteguhan lentur, keteguhan patah, keteguhan rekat, kuat pegang sekrup) terhadap MDF yang dihasilkan yang mengacu pada JIS A 5905-2003 dan pengujian ketahanan mengacu pada SNI 01-7207-2006. Keseluruhan sifat fisik MDF memenuhi standar JIS A 5905-2003. Pemberian asetat anhidrida menurunkan nilai kadar air MDF yang dihasilkan. Hasil pengujian sifat mekanik seluruhnya tidak memenuhi standar yang diacu. Hal tersebut dipengaruhi oleh kalsium karbonat dalam sludge yang menghambat ikatan antar serat sludge. Hasil pengujian keawetan MDF termasuk kedalam kelas I, yaitu sangat tahan terhadap rayap.
International Wood Products Journal, 2017
ABSTRACT Bearing strength largely affects the performance of wood connections. This study, determ... more ABSTRACT Bearing strength largely affects the performance of wood connections. This study, determines the bearing strengths of six Indonesian tropical hardwoods with different specific gravities (ranging from 0.43 to 0.84) by half-hole testing. The results for three bolt diameters were compared to the bearing strengths in the Indonesian National Standard (SNI) and the National Design Specification (NDS) for Wood Construction. Next, the bolt-bearing strengths were related to the specific gravities and mechanical properties of the woods. With increasing specific gravity, the bearing strength increased from 26 to 70 MPa. The experimentally obtained bearing strengths of light and heavy red meranti, mersawa, kapur and bangkirai woods were 3–15% and 11–23% lower than the SNI and NDS values, respectively. In contrast, the experimental result for merbau was 23 and 11% higher than the SNI and NDS values, respectively. The bearing strength most closely approached the compression strength parallel to the grain.
Kayu telah digunakan selama ribuan tahun sebagai bahan konstruksi untuk tempat tinggal, kapal dan... more Kayu telah digunakan selama ribuan tahun sebagai bahan konstruksi untuk tempat tinggal, kapal dan jembatan. Ketersediaan dan kemudahan dalam pengerjaannya pada awalnya telah membuat kayu menjadi pilihan yang logis untuk bahan konstruksi. Belakangan, pilihan ini juga disebabkan oleh biayanya yang lebih rendah dan rasio kekuatan terhadap berat yang tinggi dibandingkan dengan bahan dari logam dan semen (Falk et al., 1990). Kayu merupakan bahan yang memiliki keragaman dalam sifat-sifatnya, yang melekat secara inherent. Kayu dikenal sebagai bahan yang bersifat ortotropis. Sifat-sifat struktural kayu tidak hanya bergantung pada arah orientasinya ketika dipotong dari bentuk log tetapi juga pada distribusi, ukuran
Journal of Biological Sciences, 2010
ABSTRACT This study presents properties test results of glued-laminated (glulam) beams made from ... more ABSTRACT This study presents properties test results of glued-laminated (glulam) beams made from two fast growing tree species, namely African wood ( Maesopsis eminii ) and mangium ( Acacia mangium ) using water based polymer isocyanate (WBPI) as a binder. Laminations were used consist of 2, 4, 6, 8 and 12 cm in widthnesses, 2 cm in thickness and 260 cm in length. Each lamination was graded using Machine Stress Grading (namely by Panter or plank sorter) to determine its Modulus of Elasticity (MOE). Cross-section of five types of glulam beams was 6x12 cm, arranged of various widths and based on MOE of laminations. The study results describe that glulam beams made from mangium showed better performance compared to those of African wood based on values of MOE and Modulus of Rupture (MOR). In general, results showed that almost all of glulam beams types of both wood species fulfill the JAS 234:2003 standard in moisture content, MOE, MOR, shear strength and immersion delamination test. However, performance of glulam beams was unsatisfactory in wood failure ratio and boiling water soak delamination test.