bluuebunny/crossref_metadata_2025 huggingface dataset:
Dukungan Sosial dan Subjective Well Being Siswa Sekolah Singosari Delitua
Authors: Nugraha M. Fadli
Published: February 2021

Tujuan penelitian ini untuk melihat gambaran dukungan sosial dan subjective well being siswa yang ada di sekolah Singosari Kecamatan Delitua, Kabupaten Deli Serdang. Metode penelitian menggunakan kuantitatif deskriptif. Teknik pengambilan sampel menggunakan total sampling. Populasi seluruh siswa kelas 12 dan sampelnya sebanyak 100 siswa. Instrumen penelitian menggunakan skala jenis likert. Analisis data menggunakan analisis deskriptif. Hail penelitian menunjukkan bahwa secara keseluruhan dukungan sosial siswa rendah. Terlihat dari hasil empiris dari dukungan emosional hanya 2 siswa yang tinggi dan 30 siswa sedang dan 68 siswa rendah. Dukungan penghargaan tidak memiliki siswa yang tinggi dan sendang ada 24 siswa, rendah ada 76 siswa. Dukungan instrumental ada 6 siswa tinggi, 19 siswa sedang dan 75 rendah. Kemudian dukungan informatif ada 4 siswa tinggi, 31 sedang dan 65 rendah. Kemudian siswa yang indikator kebahagiaannya tinggi ada 3, sedang 26 dan rendah 71 siswa. Indikator kepuasan hidup ada 2, sedang 32 dan rendah 66 siswa.
Prokrastinasi Akademik Ditinjau Dari Kontrol Diri Pada Siswa-Siswi SMA Swasta Ar-Rahman Medan
Authors: Widyastari Dewinta , Atrizka Diny , Ramadhani Beby , Damanik Devi S
Published: February 2021

Penelitian ini bertujuan untuk mengetahui hubungan antara kontrol diri dan prokrastinasi akademik. Hipotesis yang diajukan dalam penelitian ini adalah ada hubungan negatif antara kontrol diri dengan prokrastinasi akademik dengan asumsi semakin tinggi kontrol diri yang dimiliki siswa-siswi, maka semakin rendah prokrastinasi akademik yang dimiliki siswa-siswi dan sebaliknya. Subjek penelitian yang digunakan dalam penelitian ini adalah siswa-siswi SMA Swasta Ar-Rahman Medan sebanyak 127 orang yang dipilih dengan metode disproportionate stratified random sampling. Data diperoleh dari skala untuk mengukur prokrastinasi akademik dan kontrol diri. Perhitungan dilakukan dengan melalui uji prasyarat analisis (uji asumsi) yang terdiri dari uji normalitas dan uji linearitas. Analisis data yang digunakan adalah menggunakan korelasi Product Moment melalui bantuan SPSS 17 for Windows. Hasil analisis data menunjukkan koefesien korelasi sebesar -0.698 dengan p sebesar 0,000 (p < 0,05). Artinya ada hubungan negatif antara kontrol diri dengan prokrastinasi akademik. Hasil penelitian ini menunjukkan bahwa sumbangan yang diberikan variabel kontrol diri terhadap prokrastinasi akademik adalah sebesar 48.7 persen dan selebihnya 51.3 persen dipengaruhi oleh faktor lain. Dari hasil penelitian ini dapat ditarik kesimpulan bahwa hipotesis penelitian ada hubungan negatif antara kontrol diri dan prokrastinasi akademik, dapat diterima.
Pengaruh Teknik Pembelajaran dan Gaya Belajar Terhadap Hasil Belajar IPS Siswa Kelas IV SDN 014680 Buntu Pane Kisaran
Authors: Lasty Widya Firdausi
Published: February 2021

Penelitian ini dilaksanakan di SD Negeri No.014680 Buntu Pane Kisaran pada semester genap tahun ajaran 2013/2014. Populasinya adalah seluruh siswa kelas IV sebanyak 50 siswa. Sampelnya adalah semua siswa yang mengambil mata pelajaran IPS sebanyak 25 siswa pada kelas IVA dan sebanyak 25 siswa pada kelas IV B. Instrumen yang digunakan untuk mengumpul data adalah tes hasil belajar IPS dan angket gaya belajar. Metode penelitian menggunakan metode quasi eksperimen dengan desain penelitian faktorial 2x2. Teknik analisis data menggunakan ANAVA pada taraf signifikan α = 0,05. Hasil penelitian menunjukkan (1) Hasil belajar IPS siswa yang diajarkan dengan teknik kunjungan lapangan lebih tinggi dibadingkan dengan teknik penyajian kasus (Fhitung = 19,86 > Ftabel = 4,05), (2) Hasil belajar IPS Siswa yang memiliki gaya belajar visual lebih tinggi dibandingkan dengan gaya belajar auditori (Fhitung = 8,65 > Ftabel = 4,05). (3) Terdapat interaksi teknik pembelajaran dan gaya belajar siswa dalam mempengaruhi hasil belajar IPS siswa auditori (Fhitung = 6,52 > Ftabel = 4,05). Data ini menunjukkan, teknik pembelajaran dan gaya belajar berpengaruh terhadap hasil belajar IPS siswa.
Intensitas Penggunaan Media Sosial ditinjau dari Kebutuhan Afiliasi Pada Siswa-Siswi Kelas XI SMA Panca Budi Medan
Authors: Octavia Ryzka Rosta , Malau Josep Hutty Pardamean , Atrizka Diny , Dewi Dearni Cintya
Published: February 2021

Penelitian ini bertujuan untuk mengetahui hubungan antara kebutuhan afiliasi dengan intensitas penggunaan media sosial. Subjek yang digunakan dalam penelitian ini adalah siswa dan siswi di SMA PAnca Budi Medan sebanyak 152 orang sebanyak 152 orang yang dipilih dengan metode purposive sampling. Data diperoleh dari skala untuk mengukur kebutuhan afiliasi dan intensitas penggunaan media sosial. Perhitungan dilakukan dengan melakukan uji analisis (uji asumsi) yang terdiri dari uji normalitas sebaran dan uji linearitas hubungan. Analisis data yang digunakan adalah menggunakan korelasi Product Moment melalui bantuan SPSS 18 for Windows. Hasil analisis data menunjukkan koefisien korelasi sebesar 0,679 dan nilai signifikansi sebesar 0,000 (p < 0,05). Ini menunjukkan ada hubungan positif antara kebutuhan afiliasi dengan intensitas penggunaan media sosial. Hasil penelitian ini menunjukkan bahwa sumbangan yang diberikan variable kebutuhan afiliasi terhadap intensitas penggunaan media sosial adalah sebesar 46,1 %, selebihnya 53,3 % dipengaruhi oleh faktor lain yang tidak diteliti. Berdasarkan hasil penelitian ini dapat ditarik kesimpulan bahwa hipotesis penelitian diterima, yaitu ada hubungan positif antara kebutuhan afiliasi dengan intensitas penggunaan media sosial.
Hubungan Pengetahuan Dengan Tingkat Kesiapsiagaan Siswa/I SMA N 9 Takengon Terhadap Bencana Gempa Bumi di Kecamatan Ketol Kabupaten Aceh Tengah Tahun 2017
Authors: Anwar Syahferi , Mahara Rike
Published: February 2021

Gempa bumi yang berkekuatan 6,2 SR melanda Kabupaten Aceh Tengah pada juli 2013 lalu meluluh lantakkan hampir seluruh wilayah Kabupaten Aceh Tengah dan Kabupaten Bener Meriah. Kecamatan Ketol adalah wilayah terparah yang terkena dampak gempa tersebut. Tanah longsor, rumah ambruk hingga korban jiwa yang tidak sedikit. Setelah terjadinya musibah tersebut, pendidikan pelatihan dan simulasi menghadapi bencana belum pernah dilakukan, namun dalam fase rehabilitasi bencana tanggap darurat hal ntersebut perlu dilakukan. apabila suatu saat dampak bencana serupa dapat minimalisir bahkan di hindari. Penelitian ini mengunakan jenis Deskriptif Korelasi dengan pendekatan Cross Sectional. Jumlah populasi sebanyak 95 orang. Tekhnik pengambilan sampel menggunakan tekhnik Total Sampling sehingga jumlah sampel sebanyak 95 orang. Analisa data yang digunakan uji spearman’s Rho. Hasil penelitian pengetahuan dengan tingkat kesiapsiagaan terhadap bencana gempa bumi diperoleh nilai p=0,000. Hal ini menunjukkan bahwa ada hubungan yang pengetahuan dengan tingkat kesiapsiagaan siswa/I SMA N 9 Takengon terhadap bencana gempa bumi di Kecamatan Ketol Kabupaten Aceh Tengah Tahun 2017. Sebagai Kesimpulan dan harapan peneliti kepada sekolah sekolah maupun pemerintah terkait untuk membentuk kegiatan kesiapsiagaan demi meningkatkan pengetahuan dan kesiapsiagaan dalam menghadapi bencana gempa bumi. Sehingga kesiapsiagaan dalam menghadapi bencana dapat lebih maksimal.
Analisis Nilai-Nilai Religius Pada Novel Bumi Cinta Karya Habiburrahman El-shirazy
Authors: Yanti Sri , Hanina Hanina
Published: February 2021

Penelitian ini bertujuan untuk mendeskripsikan nilai religius novel “Bumi Cinta” karya Habiburrahman El-Shirazy. Untuk mengetahui nilai-nilai religius menggunakan metode deskriftif kualitatif. Objek dalam penelitian ini adalah nilai-nilai religius dalam novel Bumi Cinta Karya Habiburrahman El-Shirazy, Sumber data yang di pakai menggunakan sumber data primer dan sumber data sekunder dengan teknik pengumpulan data yaitu teknik pustaka dan teknik catat dan teknik analisis data yang di gunakan adalah membaca berulang-ulang novel, menghayati, memahami, mengumpulkan data, dan menggaris bawahi, mendeskripsikan dan menyimpulkan hasil penelitian. Hasil penelitian ini dapat menjawab dari pernyataan penelitian yaitu terdapat terdapat nilai-nilai religius (akidah, syariah dan akhlak) dalam novel Bumi Cinta Karya Habiburrahman El-Shirazy. Nilai akidah dapat di lihat dari keyakinan dan kepercayaan tokoh kepada Allah Swt. Yang maha pencipta dan maha segala nya. Nilai syariah dapat di lihat dari para tokoh yang mematuhi perintah-perintah Allah Swt menjauhi segala larangan nya. Nilai akhlak dapat di lihat dari sifat para tokoh kepada Allah Swt, Rasulullah Saw, sesama manusia, dan lingkungan.
Hubungan Interaksi Sosial dengan Motivasi Kerja Karyawan PT Perkebunan Nusantara II
Authors: Tarigan Mustika , Wahyuni Nini Sri , Syaibani Rahmat
Published: February 2021

Penelitian ini bertujuan untuk mengetahui dan menguji secara empirik apakah ada hubungan antara interaksi sosial dengan motivasi kerja karyawan PT Perkebunan Nusantara II. Subjek penelitian adalah karyawan yang bekerja di PT Perkebunan Nusantara II yang berjumlah 74 orang. Alat ukur yang digunakan adalah instrumen interaksi sosial yang terdiri dari 40 aitem (α = 0.948) dan instrumen motivasi kerja yang terdiri dari 38 aitem (α = 0.906). Analisis data menggunakan teknik r Product Moment. Berdasarkan analisis data, diperoleh bahwa hipotesis yang diajukan dalam peneltian ini dinyatakan diterima, yaitu ada hubungan antara interaksi sosial dengan motivasi kerja karyawan. Artinya semakin baik interaksi sosial maka semakin tinggi motivasi kerja karyawan. Hal ini dibuktikan melalui perhitungan analisis r Product Moment dengan nilai atau koefisien (Rxy) = 0.397 dan koefisien determinan (R2) = 0.158 dengan p = 0.000 < 0.050. Koefisien determinan (R2) = 0.158 menunjukkan bahwa interaksi sosial berhubungan dengan motivasi kerja sebesar 15,8%. Selanjutnya dilihat dari perhitungan mean hipotetik = 100 dan mean empirik 119.135 serta standat deviasi = 14.359 diketahui bahwa interaksi sosial dalam kategori baik. Sedangkan motivasi kerja dari perhitungan mean hipotetik = 95.00 dan mean empirik 116.648 serta standart deviasi = 12.444 diketahui bahwa motivasi kerja dalam kategori tinggi.
Survei Pilihan Karir Ditinjau dari Profil Kepribadian DISC Pada Calon Karyawan PT. X Indonesia
Authors: Bantam Dian Juliarti
Published: February 2021

This study aims to identify the career choice of prospective employees at PT. X Indonesia, which is reviewed by the personality profile mapping. This research is a survey that involving 211 subjects, in which the personality profile is measured using the DISC test. The results showed that prospective employees of PT. X Indonesian who have dominant personality type D are 15 subjects (7,11%), dominant personality type I are 13 subjects (6.16%), dominant personality type S are 92 subjects (43.60%) and the last personality dominant type C as many as 91 subjects (43.13%). In addition, the results also show that there are 17 career choices and dominant personality types. Account Managers, Contact Centers, Drivers, Online Sales Officers and Receptionists have the dominant type S. Admin, Branding and Communication Manager, Finance and Accounting, Web Developers, and Human Resources Operations, have dominant type C. There are also Business Development, Graphic Designer, Office Boy, Telemarketing and Recruitment Staff have dominant type S and type C. Meanwhile, Chemist Assistant has dominant type D and C, and Sales Manager with dominant type D, type S and type C.
Pentingnya Layanan Konseling Kelompok Terhadap Harga Diri Remaja
Authors: Yunita Yunita
Published: February 2021

Artikel ini menjelaskan tentang pentingnya layanan konseling kelompok terhadap harga diri remaja. Layanan konseling kelompok ialah suatu proses konseling antara konselor professional dengan beberapa konseli sekaligus dalam sebuah kelompok kecil di waktu yang bersamaan. Layanan konseling kelompok pada dasarnya merupakan layanan konseling individual yang dilakukan dalam suasana kelompok. Disana ada konselor dan klien, yaitu “para anggota kelompok” (yang jumlahnya lebih dari dua orang). Pada layanan konseling kelompok diusahakan tercipta suasana yang sama seperti dalam konseling individual yaitu hangat, permisif, penuh keterbukaan dan juga intimasi. Dimana konseli dapat mengungkapkan dan saling memahami masalah anggota kelompok, menelusuri sebab-sebab terjadinya permasalahan serta upaya pemecahan masalah. Sedangkan harga diri remaja merupakan penilaian pribadi individu yang dilakukan pada diri sendiri baik secara positif maupun negatif yang dilandaskan hubungan dan interaksi dengan orang-orang penting di sekitarnya dan juga dipengaruhi sikap, penerimaan, penghargaan dan perlakuan orang lain terhadap diri individu. Harga diri sering dinilai sebagai peringkat dengan dimensi yang berkisar mulai dari negatif sampai positif maupun rendah sampai tinggi. Diharapkan setelah membaca artikel ini dapat melakukan layanan konseling kelompok dengan maksimal dalam meningkatkan harga diri remaja baik di sekolah maupun di luar sekolah.
Pengaruh Penyuluhan Kesehatan Tentang Penggunaan Alat Pelindung Diri Terhadap Perilaku Petani Di Desa Petukel Blang Jorong Kecamatan Bandar Kabupaten Bener Meriah Tahun 2019
Authors: Zuidah Zuidah , Yanti Salda
Published: February 2021

Pemakaian alat pelindung diri merupakan salah satu cara pencegahan terjadinya keracunan pestisida. Pestisida dapat masuk kedalam tubuh melalui kulit dan sistem pernapasan. Menurut WHO di seluruh dunia terajadi 4 ratus ribu- 2 juta mengalami keracunan pestisida. Tujuan penelitian ini untuk mengetahui pengaruh penyuluhan kesehatan tentang penggunaan alat pelindung diri terhadap perilaku di Desa Petukel Blang Jorong Kecamatan Bandar Kabupaten Bener Meriah Tahun 2019. Penelitian ini menggunakan desain Pra-eksperimen dengan rancangan one group pretes and posttest, populasi dalam penelitian ini adalah seluruh petani yang menggunakan pestisida sebanyak 456 orang. Teknik pengambilan sampel dengan accidental sampling, jumlah sampel sebanyak 30 orang. Instrumen yang digunakan menggunakan kuesioner dan leflet. Analisa data dilakukan dengan univariat dan bivariat menggunakan Wilcoxon signed rank test. Hasil penelitian bahwa perilaku sebelum diberikan penyuluhan kesehatan tentang penggunaan alat pelindung diri mayoritas kurang sebanyak 15 responden (50%), perilaku sesudah diberikan penyuluhan kesehatan tentang penggunaan alat pelindung diri mayoritas baik sebanyak 21 responden (70%). Hasil uji statistik dengan uji wilcoxon pengaruh pengaruh penyuluhan kesehatan tentang penggunaan alat pelindung diri terhadap perilaku di Desa Petukel Blang Jorong Kecamatan Bandar Kabupaten Bener Meriah Tahun 2019 dengan nilai P-value 0,000. Kesimpulan penelitian terdapat pengaruh penyuluhan kesehatan tentang penggunaan alat pelindung diri terhadap perilaku di Desa Petukel Blang Jorong Kecamatan Bandar Meriah Tahun 2019. Disarankan untuk pihak aparat desa untuk dapat memberikan informasi tentang penggunaan alat pelindung diri yang baik pada petani sehingga mengurangi terjadinya keracunan pada petani.
In Search of Substitution Material for Traditional Javanese Wooden Houses
Authors: Prihatmaji Yulianto P. , Kitamori Akihisa , Komatsu Kohei
Published: February 2021

Many Javanese traditional timber structures have been destroyed by major earthquake. The impact of the disaster demanded a deeper finding on timber materials for repairing and reconstructing. To understand the mechanical property of timber for Javanese timber house, compression test were carried out for radial and tangential direction. Traditional joint construction use mortise and tenon system that stress yield in intersection occurred. Compression property and partial compression property is quite important for traditional joint construction. Especially, the mechanical properties against density of tropical timber were studied.                                In this paper, authors showed substitute materials for Javanese timber houses from tropical timber. A total of 288 specimens made from six tropical timber species were tested. All of tropical timber specimens showed strong relationship between Young’s modulus (E) and density. There was clear trend that the smaller density indicated the smaller Young’s modulus. Jati, Nangka, Sonokeling, Ketepeng and Acacia had similar increasing mechanical properties, while in the case of specimen Falcata, it mechanical properties were stagnant. The bigger density indicated the bigger Young’s modulus. Acacia and Ketepeng have MOE and density nearby Jati. Both of specimens has also similar tendency of mechanical properties with Jati.
Development of Earthquake-proof Fittings of Traditional Wooden Frame Structures
Authors: Wakita Takehiro , Konuta Fuyuki , Kitamori Akihisa , Kataoka Yasuo
Published: February 2021

There are many old traditional wooden frame buildings which were specified as cultural heritage or will be specified as Japanese important building in the near future. But there are many buildings which do not have good performance against seismic action. The purpose of the investigation is to develop the earthquake proof fittings, and to apply them to the traditional wooden structures. In concrete terms, the types of the earthquake-proof fittings are the Kamachi door, the acrylic door and the hinged wooden door. Strength and rigidity of the earthquake proof fittings were estimated experimentally, and they were applied to reinforce the two old Buddhist temples.
Chemical and Mechanical Properties of Cuticular Membranes Isolated from Young Matured Leaves of Sonneratia alba
Authors: Takahashi Yuki , Tsubaki Shuntaro , Sakamoto Masahiro , Watanabe Shin , Dwianto Wahyu , Azuma Jun-ichi
Published: February 2021

Leaf cuticular membranes (CMs) of Sonneratia alba are considered to play an important role in environmental tolerance, and chemical and mechanical properties of their CMs are crucial factors which provide protective barrier and mechanical supports.  Leaf CMs were enzymatically isolated from both adaxial and abaxial sides of young matured leaves (L3), and their chemical and mechanical properties were compared. Chemical compositions of both CMs were similar reflecting their morphological similarity.  The adaxial CM was consisted of 23.4% wax, 64.2% cutin, 7.4% cutan and 6.1% polysaccharides with thickness of 9 µm, and the abaxial CM had the values of 23.9%, 63.2%, 9.4%, 4.2% and 8 µm, respectively.  Major monomers in both cutins were 9,10-epoxy-18-hydroxyoctadecanoic acid and 9(10),16-dihydroxyhexadecanoic acid.  Mechanical properties of both CMs were also similar reflecting their morphological and chemical compositional similarities.
Relationship between Growth and Wood properties in Agathis sp. Planted in Indonesia
Authors: Ishiguri Futoshi , Makino Kazuko , Wahyudi Imam , Tanabe Jun , Takashima Yuya , Iizuka Kazuya , Yokota Shinso , Yoshizawa Nobuo
Published: February 2021

The present study clarified the relationship between the growth and wood properties of 54-year-old Agathis sp. trees planted in Indonesia. Stem diameter, pilodyn penetration, and stress-wave velocity (SWV) were measured for all trees (35 trees) in a plot (30  30 m) located almost at the center of a stand. Based on the mean stem diameter, 10 standard trees in a plot were selected for measuring the basic density (BD) and compressive strength parallel to grain (CS). Core samples (5 mm in diameter) were collected from the 10 selected trees to determine BD and CS. The mean stem diameter, pilodyn penetration and SWV in the plot were 40.2  11.3 cm, 23.4  2.1 cm, and 3.85  0.43 km/s, respectively. No  significant correlation coefficeint (r = -0.327, no significance at 5% level) was obtained between stem diameter and SWV. The mean BD and CS in the 10 trees were 0.42  0.03 g/cm3  and 28.1  2.7 MPa, respectively. A significant positive  correlation was observed between BD and CS. Analysis of variance (ANOVA) revealed a significant difference between BD and CS values of the 10 trees, indicating that wood properties may differ among trees with the same standard growth in a stand. From these results, we concluded that wood quality improvement in this species could be achieved by selecting  trees with high density and strength in tree breeding programs.
Indonesian Wood as Material for Acoustic Guitars and Violins
Authors: Kusumaningtyas Indraswari , Subagio Subagio
Published: February 2021

Traditionally, acoustic guitars and violins are made from European woods. Spruce is most preferred for the top plate (soundboard), whereas maple, sycamore and rosewood are often used for the back plate. However, these woods are not easily available in Indonesia. In this paper, we present a study on the suitability of a selection of Indonesian woods, namely acacia, mahogany, pine, sengon and sonokembang, as materials for acoustic guitars and violins. The most important acoustical properties for selecting materials for musical instruments, i.e. the speed of sound, the sound radiation coefficient and the damping factor, were investigated. Furthermore, the performance of pine and mahogany were tested by making them into a violin and a guitar. The vibration frequency spectrum and the damping factor of the top plate were measured. The results show that the acoustical characteristics of mahogany are very close to those of maple and still quite close to those of Indian rosewood, which makes it a very suitable local material for back plates. Pine has quite similar acoustical characteristics to spruce. Although its sound radiation coefficient is slightly lower, its aesthetic appeal and workability makes pine a suitable alternative for top plates. However, instruments with pine top plates exhibit different tonal colour compared to instruments with spruce top plates, due to some differences in the vibration frequency spectrum. Furthermore, the generally higher damping factors of pine and mahogany compared to those of the European woods should be taken into account, because they affect the sustain-time of the generated sound.
Chemotaxonomic Study in the Heartwood of Javanese Teak: Analysis of Quinones and Other Related Components
Authors: Lukmandaru Ganis
Published: February 2021

Ethanol-benzene soluble extracts from the heartwood collected from 87 individual teak trees grown in the island of Java were analyzed using GC and GC-MS. The variations of quinones (tectoquinone, deoxylapachol, isodeoxylapachol, lapachol, tectol) and other components (palmitic acid, squalene, and two unknown compounds) were investigated for a chemotaxonomical study. There were wide variations in the contents of the constituents among individuals from three habitats, Purwakarta (plantation forest), Randublatung (plantation forest)  and  Gunungkidul (community forest)  regions. Cluster  and  discriminant analysis  results  showed  that  teak  trees  can  be  classified  into  three  clusters  based  on  the composition of quinones and squalene. Cluster I was distinguished by relatively high amount of squalene and low amount of quinones. In contrast, high amount of tectoquinone and low amount of squalene was observed in cluster III. Further, comparatively high amount of naphtaquinones (lapachol, deoxylapachol and its isomer) and tectol was found in cluster II. Based on geographical distribution, Purwakarta, Randublatung, and Gunungkidul regions mostly produce cluster II, I, and III type individuals, respectively.
Expression of Xyloglucanase (AaXEG2) in Open-field-grown Poplars
Authors: Iizuka Haruka , Kaku Tomomi , Taniguchi Toru , Kurita Manabu , Konagaya Ken-ichi , Ishii Katsuaki , Kondo Teiji , Baba Kei’ichi , Kaida Rumi , Taji Teruaki , Sakata Yoichi , Hayashi Takahisa
Published: February 2021

The transgenic expression of Aspergillus aculeatus xyloglucanase with 35S promoter, which has been maintained in greenhouse-grown transgenic poplars for 10 years, was assessed to determine their expression level in open-field-grown poplars. This level was slightly decreased in the poplars grown in fertile soil for four years, and there were proportionatel y decreased levels of xyloglucanase activity among their tissues, in which the shoots exhibited slightly lower specific activities than was observed in the leaves and roots. Xyloglucan content was greatly decreased in the walls of the tissues in the transgenic lines, although the degradation levels of xyloglucan were slightly lower for the poplars grown in fertile soil than for those grown in non-fertile soil. The results showed that the level of expression, together with xyloglucan degradation in their walls, was decreased for the poplars grown in fertile soil.
Mechanical Properties of Cocos nucifera Wood Planted Around Mt. Merapi, Yogyakarta
Authors: Awaludin Ali , Sutapa J.P. Gentur
Published: February 2021

This study presented test results of mechanical properties of Cocos nucifera wood that were planted around Mt. Merapi, Yogyakarta. The test specimens were obtained from trees that had been exposed to pyroclastic flow during the 2010 volcanic eruption as indicated by dark colour of the outer bark. Test set-up was designed according to ASTM D143-94 and the mechanical properties, which are determined based on the lower 5% exclusion limit, were bending strength, shear strength, dowel bearing strength and compressive strength. Results of the specific gravity measurement showed significant variation of specific gravity between the inner part (close to the pith) and the outer part (far from the pith) in a cross-section. Since mechanical properties generally depend upon specific gravity, it was decided to divide the wood specimens into two groups: specimens from the inner part and specimens from the outer part. Most of the mechanical properties of wood specimens from the inner part, except for bending strength, were found to be much lower than E10 grade of the Indonesian National Standard (SNI). Hence it is not recommended for any structural use. In the case of wood specimens from the outer part, their mechanical properties were as follows: bending strength 83.66 MPa; shear strength parallel to grain 4.41 MPa; dowel bearing strength parallel to grain 40.65 MPa; dowel bearing strength perpendicular to grain 25.88 MPa, compressive strength parallel to grain 37.89 MPa; and compressive strength perpendicular to grain 7.48 MPa. It seemed that the wood specimens from the outer part had excellent mechanical properties especially in bending, but their shear strength is extremely low.
Effect of Melaleuca leucadendron, Cananga odorata and Pogostemon cablin Oil Odors on Human Physiological Responses
Authors: Pujiarti Rini , Ohtani Yoshito , Widowati Titis Budi , Wahyudi Wahyudi , Kasmudjo Kasmudjo , Herath N. Kaushalya , Wang Chao Nan
Published: February 2021

The aims of this study were to evaluate the main compounds and the effect of M. leucadendron, C. odorata and P. cablin essential oil odors on human physiological responses. The chemical compounds of essential oils in this study were analyzed by gas chromatography-mass spectrometry (GC-MS) and the physiological effects of essential oils on human were analyzed via the sense of smell olfactory system. Physiological parameters of systolic blood pressure, diastolic blood pressure, pulse rate, stress index, and brain wave were recorded before and after sniffing essential oils. The result shows that the main compound of M. leucadendron, C. odorata, and P. cablin is 1,8-cineole, Caryophyllene and Patchouli Alcohol, respectively. Our results demonstrated that M. leucadendron and C. odorata oil odors possessed sedative effect and P. cablin oil odor had tendency to contain stimulating effect on human physiologies.
Effects of Temperature and Time of Carbonization on the Properties of Bamboo (Dendrocalamus asper) Carbon
Authors: Subyakto Subyakto , Budiman Ismail , Pari Gustan
Published: February 2021

Lignocellulosic materials such as wood and bamboo have special characteristics when carbonized at high temperature. For example the electrical conductivity of wood and bamboo increases when carbonized at temperature of 800°C or higher. This property can be used for developing smart materials such as fiber reinforced concrete which has function as sensors for load, damage or temperature. In this experiment, betung bamboo (Dendrocalamus asper) was carbonized at different temperatures and times of carbonization. The purpose of this experiment was to observe the effect of temperature and time of carbonization on the properties of bamboo carbon. Bamboo in the form of particles were carbonized at temperature of 400°C for 300 min and continued at temperatures of 700, 800, or 900°C for 45, 60, or 90 min. Carbon properties such as yield, fixed carbon, volatile matters, and ash content were determined. Structure properties were studied by X Ray Diffraction (XRD), morphological properties were observed by Scanning Electron Microscope (SEM), and electrical conductivity was measured using LCR meter. Result shows that increasing temperature and time of carbonization have significant effects on the structure and other properties of bamboo carbon. Carbonization at temperature of 800°C for 60 min was considered as an optimum condition.
Equations of the Sum of Shear Connector on the Double Shear Connection Strength using Different Connector Materials
Authors: Priyono Dwi Joko , Surjokusumo Surjono , Hadi Yusuf S. , Nugroho Naresworo
Published: February 2021

Mangium wood from the timber estate have been developed continuously in an effort to reach the fulfilling of wood fiber and construction material needs to replace role of timber from the natural forests which has been decreased. Timber connection requires a connector such as bolt that can distribute both the load of wood to wood and the compression or tensile stress through all the connections. Bearing slip is a connector that is inserted into a hole in the wood, which bears pressure and shear. Bolted connection is the most commonly used because it is easy to apply, even though it is less efficient due to the shear forces will be retained by the bolts and wood only on the cross-sectional area of the bolt. This research trying to find the equations of the sum of  bearing slip connector to the strength of double shear connection  which composed of 17 years old mangium. The connector was made from  different materials that consisted of the same mangium, compressed mangium, ironwood and steel. The bearing slip connector consisted of two forms (dowel and rectangular) and arranged on one until three pairs of connector. The size and placement of the double-shear component based on Anonymous (2002), each form of the sample was made in 4 replications and all of them have been tested using a 35-ton Baldwin UTM. The result showed that the rectangular steel bearing slip connector has the highest equation (y = 5322e0.329x ) meanwhile the lowest equation was the ironwood materials (y = 3164e0.405x ). All of equations give high correlations ( R2 between 0.743 to 0.947).  Bearing slip connector can improve the ability of the connection in load-bearing. Densified of mangium able to raise the connection system's ability however not significantly, both in strength and displacement. Ironwood connector are not well used as a retaining shear pin because of easy to split and significantly much below in capacity than mangium wood. Steel connector resulted the higher load-bearing significantly than mangium and ironwood. Dowel do not differ in terms of strength as compared with rectangle, and each additional number of connector producing an increase in load-bearing ability significantly. Observation on the displacement value shows that for the value which applied usually in Indonesia reach the strength ratio (SR) as 92.21% to the proportion limit and 44.91% to the maximum load. This value was in below position of the US standard  (24.17 and 11.77%) and of the Australian standard (51.46 and 25.06%) to the proportional limit and maximum load respectively. Displacement achievement at the proportional limit varies from 1.1 to 2.2 mm, so that the minimum requirement of 1.5 mm displacement is not fulfilled by some treatments, however all of the connection system have passed the 1 mm displacement.
Effects of Nodes on the Properties of Laminated Bamboo Lumber
Authors: Sulastiningsih I. M. , Ruhendi Surdiding , Massijaya Muh. Yusram , Darmawan I Wayan , Santoso Adi
Published: February 2021

The objective of this study was to determine the effects of node on the properties of laminated bamboo lumber (LBL) glued with water based polymer-isocyanate adhesive. Bamboo strips for LBL fabrication were prepared from andong bamboo (Gigantochloa pseudoarundinacea) collected from private gardens in West Java. Each bamboo strip has dimension of 40 cm x 2 cm x 0.5 cm. The bamboo strips were assigned into 3 groups by the node positions: without node, with node position of 10 cm from one end of the bamboo strip, and with node position in the centre of the bamboo strip. Prior LBL fabrication, the bamboo strips were treated by cold soaking in 7% boron solution for 2 h. The laboratory scale 3-layer laminated bamboo lumbers were manufactured with 5 different layer compositions: all layers made of bamboo strips without node, inner layer made of bamboo strips with nodes at 10 cm from one end of the strip, inner layer made of bamboo strips with nodes at the centre of the strip, all layers made of bamboo strips with nodes at 10 cm from one end of the strip, and all layers made of bamboo strips with nodes at the centre of the strip.  The glue spread and cold pressing time applied were 250 g/m2 and 1 h, respectively.The results showed that the average density, moisture content, thickness swelling, bending strength and compression strength of laminated bamboo lumbers were 0.74 g/cm3, 11.3%, 2.9%, 1090 kg/cm2,and560 kg/ cm2, respectively. No delamination occurred in all samples, indicating high bonding quality. The average bonding strength (dry test) of laminated bamboo lumbers was 70.3 kg/cm2. Several properties of laminated bamboo lumber were not significantly affected by the present of nodes in the bamboo strips except the thickness swelling and compression strength.
Effects of Shelling Ratio and Particle Characteristic on Physical Properties of Three-Layered Particleboard Made from Different Wood Species
Authors: Rofii Muhammad Navis , Yumigeta Satomi , Suzuki Shigehiko , Prayitno Tibertius Agus
Published: February 2021

Wood waste materials such as flakes, particles, sawdust, planer shaving, which are residues from furniture industry can be utilized to manufacture many composites such as particleboard. The most commonly used particleboard has three layers: two face layers and one core layer. The face layers consist of fine particles and the core layer is made of coarse particles.This study aimed to show the effect of shelling ratio and particle characteristic on physical properties of three-layer particleboard with high density core and different particles on surface layers. The materials used in this study were hinoki (Chamaecyparis obtusa) strand and knife-milled Douglas-fir (Pseudotsuga manziesii) as surface layers and hammer-milled matoa (Pometia sp.) as core layer. The wood particles were collected from a wood company. Adhesive used was MDI resin (methylene diphenyl diisocyanate) with 6 % content in mat preparation. The pressing conditions were: temperature 180°C, pressure  3 MPa and pressing time  5 min. The target density was 0.72 g/cm3 with board size of 340 mm x 320 mm  x 10 mm. Factors used in this study were layer structure according to board shelling ratio and particle characteristic. The parameters of this study were density, moisture content, thickness swelling, water absorption, linear expansion and vertical density profile.The results of this study indicate that all boards meet the requirements of JIS A 5908-2003. Higher shelling ratio of surface layers resulted in higher physical performance of three-layer particleboard. In terms of particle type, hinoki strands showed the best performance in board density and linear expansion, while Douglas-fir particle showed the best performance in moisture content, thickness swelling and water absorption. Improvement of physical properties of particleboard with high density wood particles in core layer can be conducted by adding surface layer with higher quality wood particles such as hinoki strands or Douglas-fir particles. Compared to Douglas-fir particles, hinoki strands as surface layers contribute to higher enhancement of three-layer particleboard with matoa as the core layer.
Removal of Arabinose Substituents from Corn Pericarp Arabinoxylan
Authors: Yoshida Tomoki , Dwianto Wahyu , Honda Yoichi , Uyama Hiroshi , Azuma Jun-ichi
Published: February 2021

Partial acid hydrolysis of corn pericarp arabinoxylan (arabinose/xylose (A/X) ratio 0.35 and mean molecular weight of  53.6 × 103) was carried out at pH 1.0 for 1 ~ 6 h at 37 ~ 57 °C to remove arabinose substituents. The removal of arabinose could be described by regression analysis with the method of least squares. Following the regression profile, three kinds of desubstituted arabinoxylans having A/X ratios of 0.25, 0.12 and 0.03 with mean molecular weight values of 37.3 × 103, 15.6 × 103 and 7.2 × 103, respectively, could be prepared.  All corn pericarp arabinoxylans were in the amorphous state and the film formability of the native state was lost after the partial acid hydrolysis.
Wood Properties of Three Fruit Tree Species Planted in Central Kalimantan, Indonesia
Authors: Aiso Haruna , Ishiguri Futoshi , Makino Kazuko , Wahyudi Imam , Takashima Yuya , Ohkubo Tatsuhiro , Iizuka Kazuya , Yokota Shinso
Published: February 2021

The objective of this study was to evaluate the properties for wood utilization of fruit trees planted in Central Kalimantan, Indonesia. A total of 9 jambu bol (Syzygium malaccense), rambutan (Nephelium lappaceum), and durian (Durio zibethinus) trees were randomly selected from the plot (20 by 30 m) and measured for stem diameter, tree height, stress-wave velocity (SWV), and Pilodyn penetration of the trees. Mean values of stem diameter were 11.8, 15.9, and 29.3 cm for S. malaccense, N. lappaceum, and D. zibethinus, respectively. Mean values of stress-wave velocity were 3.16, 3.95, and 3.63 km/s for S. malaccense, N. lappaceum, and D. zibethinus, respectively. Core samples (5 mm in diameter) were collected from these trees to investigate the wood properties [basic density (BD) and compressive strength parallel to grain (CS)], anatomical characteristics [vessel diameter (VD), cell wall thickness (CWT) in wood fiber, and cell length (CL) of wood fiber and vessel element], and amounts of chemical components. In VD, CWT in wood fiber, and CL in wood fiber and vessel element, almost the same radial variation patterns were found in the three species. Relatively higher values in SWV, BD, and CS were found in N. lappaceum, suggesting that its wood can be used for construction lumber. On the other hand, S. malaccense and D. zibethinus had relatively thicker CWT in wood fiber, longer CL in wood fiber, and lower Klason lignin content. It is considered that the wood of these two species may be suitable for pulpwood.
Eco-friendly Board from Oil Palm Frond and Citric Acid
Authors: Syamani Firda Aulya , Munawar Sasa Sofyan
Published: February 2021

The utilization of oil palm fronds as composite board raw material has developed due to the declining wood supply. Currently, citric acid is used as natural adhesive on the wood-based moldings to reduce the use formaldehyde-based resin. Citric acid has carboxylic acid functional group that can react with hydroxyl functional group from cellulose by esterification reaction. This paper explain the production of board from oil palm frond and citric acid, then elaborate their physical and mechanical properties.  Oil palm fronds were processed with ring flaker to produce particles with 1 ~ 5 cm length. The particles were dried until the moisture content reached 6%. Citric acid solution was obtained by stirring 700 g citric acid in 1000 ml water.  Citric acid solution were sprayed onto particles. The weight of citric acid were 10%, 15% and 20% based on oil palm fronds’ dry weight. Boards were produced with density target of 0.6 g/cm3 and pressure at 1N/mm2 for 10 min. The hot pressing temperatures were varied at 140ºC, 160ºC, 180ºC, and 200ºC. Physical and mechanical test were performed according to JIS A 5908-2003. The MOR, MOE, IB and SW values of boards with 15 wt% citric acid content and pressed at 200oC were 5.85 N/mm2, 1067.03  N/mm2, 0.26 N/mm2 and 88.80 N respectively. The optimum condition for board production obtained upon citric acid content and pressing temperature in a range of 15% ~ 20% and 180ºC ~ 200ºC, respectively.
Degradation Analysis on Manufacture of Cement-bonded Particleboard Using Supercritical CO2
Authors: Maail Rohny Setiawan
Published: February 2021

This study analyzed the degradation process on manufacture of cement-bonded particleboard (CBP) using supercritical CO2. CBP with a target density of 1.2 g/cm3 was manufactured at a cement / wood particle / water weight ratio of 2.5:1.0:1.25. As references, neat cement board (NC) was manufactured at a cement / water weight ratio of 2.5:1.25, and Ca(OH)2 board was manufactured at a Ca(OH)2 / wood particle / water weight ratio of 3.0:1.0:1.5. Hand-formed mat of 230 x 230 mm was cold-pressed to a targeted thickness of 12 mm and kept in an oven set at 60ºC for 24 h. Four specimens of 50 x 210 mm prepared from these boards were then used for curing treatment. The three curing treatments were (1) supercritical CO2 treatments, 10 min to 10 days; (2) conventional curing treatment for 28 days (Conventional); and (3) neither curing nor supercritical CO2 treatment as the control. The chemical changes and the mineralogical composition of the curing and the degradation processes of the CBP were examined using X-ray diffractometry (XRD), thermal gravimetry (TGA-DTG), and scanning electron microscopy (SEM) observation. Significant correlations were found between the supercritical CO2 treatment and mechanical properties during both the curing and degradation processes. Internal bond (IB) strength, modulus of rupture (MOR), and modulus of elasticity (MOE) values of CBP achieved their maximums by supercritical CO2 treatment in 30 min. These conditions indicated that supercritical CO2 treatment accelerates the curing process rapidly and enhances the mechanical properties of the CBP.  However, these values decreased in the treatments from 60 min to 10 days and had a negative effect on board performance, indicating that supercritical CO2 treatment over a longer time span leads to the degradation of the CBP. Furthermore, X-ray diffractometry (XRD), thermal gravimetry (TG-DTG), and scanning electron microscopy (SEM) observation clarified that the mechanisms of the degradation are directly affected by the mineralogical composition of the system, in particular by the calcium carbonate content as caused by carbonation.
Dimensional Stability and Characteristics of Modified Young Teak (Tectona grandis L.f.) Wood with PEG-1000
Authors: Listyanto Tomy , Rofii Muhammad Navis , Ando Keisuke , Hattori Nobuaki
Published: February 2021

The aim of this study was to investigate the effect of wood modification with polyethylene glycol (PEG)-1000 at five concentrations to improve dimensional stability, drying, machining and finishing characteristics of young teak wood. A total of 12 samples for each treatment was prepared to measure an Anti Shrink Efficiency (ASE), as a parameter of dimensional stability and its drying characteristics. Six samples for each treatment were prepared to evaluate machining and finishing characteristics. PEG-1000 with five concentration levels of 20%, 30%, 40%, 50% and 60% were impregnated to modify the samples, except control. Afterward, all samples were kiln dried to gain 12% moisture content. ASE was determined by comparing shrinkage percentage of treated sample with those of untreated one. Warping and surface checks were measured as drying characteristics and machining test was conducted in accordance to ASTM D1666-2004. After coating with a nitrocellulose system, surface quality were evaluated by conducting cross-cut test (ASTM D3359), coin test, delamination test (SNI 01-5008.2-1999b) and glossyness test (SNI-06-6052-1999a). Result shows that dimensional stability of impregnated samples with concentration of 30~60% was successfully improved, with ASE of 52~62%. All treated samples demonstrated good drying characteristics and defect-free areas which were more than 90% under machining test. Surface evaluation by delamination test, glossyness test, and coin test indicated that all impregnated samples were well coated by a nitrocellulose system. However, only impregnated samples in concentration of 20% and 30% showed a good result in cross-cut test. Impregnation with PEG-1000 in concentration of 30% is recommended to modify young teak wood.
Pore Size Distribution and Microstructure of Oil Palm Shell Heat Treated at 300 C Followed by Slow or Fast Heating Treatment
Authors: Sulistyo Joko , Hata Toshimitsu , Imamura Yuji , Darmaji Purnomo , Marsoem Sri Nugroho
Published: February 2021

Pore size distribution and microstructure development of oil palm shell heat treated at 300ºC and treated at 300ºC and recarbonization at 600ºC followed by slow- or fast heating treatment up to 700ºC were investigated by small angle X-ray scattering (SAXS), N2 gas adsorption and Raman spectroscopy. On oil palm shell heat-treated at 300ºC, slow heating treatment gave the widening micropore along with the ordering microstructure; but fast heating treatment produced charcoal with a narrow diameter of micropore with wider pore size distribution and the disordering microstructure. On oil palm shell heat treated at 300ºC and recarbonization at 600ºC, slow heating treatment contributed on the opening new micropore with ordering microstructure, but some parts of micropore showing inaccessible for N2 gas. Meanwhile, fast heating treatment with the heating rate from 75 to 250ºC/min increased BET surface area with similar pore size distribution and the disordering microstructure.
Correlation of the Areal Number Density of Vascular Bundles with the Mechanical Properties of Oil Palm Wood (Elaeis guineensis Jacq.)
Authors: Choowang Rattana
Published: February 2021

Currently most of oil palm trunks in Thailand are left on the field to rot or are burnt in the field, not utilized as lumber. To promote such value-added uses, the objective of this study was to characterize the levels and variation within oil palm trunks of their key mechanical properties. In addition, the vascular bundle population was assessed, because this structural characteristic affected density and mechanical properties. The key ones being here were modulus of rupture (MOR), modulus of elasticity (MOE), and hardness. The 25 years old oil palm trunks were selected from a palm plantation in Surat Thani Province, in southern Thailand. The trees were cut down at 500 mm above ground, cut into dices, then sawn into small pieces in radial direction. Vascular bundle populations and basic densities were determined. Oil palm lumber was sawn from the logs between wood dices, and their mechanical properties were determined. The results indicated that the vascular bundle population density gradually decreased towards the central axis of trunks, and the population density positively correlated with basic density and mechanical properties. This was because the main component of a vascular bundle has fibers with thick cell walls. The data obtained may help select or create products that match the properties of oil palm wood (Elaeis guineensis Jacq.), or contributed to the sorting of wood raw material based on, for example, machine vision.