Judul: Penurunan Kadar Sukrosa dan Total Koloni Fungi Papan Partikel Ampas Tebu dengan Perendaman Air dan Penambahan Fungisida
Abstrak: Bagasse was the materials that can be used as a raw material for particle board. The problem that occured in bagasse was odor caused by the growth of fungi which appear as a result of the sucrose content in material. The objectives of this research were to find out the effect of soaking and fungicides addition on sucrose levels and fungi colony counts, to obtain best combination of both treatments, and to know the physical properties of bagasse particleboard resulted. Hot and cold soaking and fungicides addition on level 0.000, 0.125, and 0.250 g/L of water used to reduce the levels of sucrose and inhibit fungi growth. Sucrose content test showed that the best treatment was in hot soaking with total sucrose 0.717%. The best total fungal colony test was in fungicide 0.125 g/L with a total value of 0 colony. There was a significant correlation between soaking and fungicide added with the density, water content, water absorbsion, and swelling thickness analysis. The best treatment in the research was in bagasse particleboard with hot soaking treatment and fungicide level 0.125 g/L.
Keyword: fungicide, soaking, particle board, bagasse

Judul: Characteristics of Polyester-Coconut Fiber Composite Board with the Addition of Sorghum Bagasse Powder
Abstrak: Produktivitas hutan Indonesia semakin menurun, sedangkan kebutuhan manusia akan bahan baku kayu semakin meningkat seiring dengan bertambahnya jumlah penduduk. Salah satu solusi untuk mengatasi masalah ini antara lain dengan mengembangkan pambuatan metrial papan komposit. Penelitian ini bertujuan untuk membuat papan komposit polyester berpenguat serat kelapa dengan penambahan serbuk bagas sorgum terhadap kualitas papan komposit polyester. Penelitian ini menggunakan metode dengan 2 faktor yaitu presentase kadar partikel (20%, 30%, dan 40%) dan variasi ukuran mesh sorgum (40-60 mesh dan lolos 60 mesh) dengan kadar matrik resin polyester 70% dan penambahan hardener 3%. Kerapatan target papan komposit polyester 1 g cm-3 . Secara keseluruhan kerapatan papan berkisar antara 1,10-1,15 g cm-3 . Campuran papan komposit polyester-serat kelapa dengan serbuk bagas sorgum dapat meningkatkan sifat fisis, mekanis, dan impak. Kadar partikel hanya berpengaruh nyata pada kekuatan impak papan sehingga dapat meningkatkan nilai kekuatan papan komposit. Ukuran partikel tidak berpengaruh nyata terhadap sifat fisis, mekanis dan impak papan komposit. Papan komposit dengan presentase kadar partikel yang tinggi dapat meningkatkan nilai kuat tarik dan impak pada papan., The productivity of Indonesia's forests is declining gradually everyday, while the human needs for the raw materials such as wood is increasing along with the increasing population. One possible solution for this problem is to develop composite materials manufacturing. The purpose of this study is to make polyester composite boards reinforced with coconut fiber with the addition of sorghum bagasse powder to increase the quality of polyester composite boards. This method uses 2 factors, namely the percentage of particle content (20%, 30%, and 40%) and variations in the size of the sorghum mesh (40-60 mesh and 60 mesh) with a matrix content of 70% polyester resin and the addition of 3% hardener. The target density of polyester composite board is 1 g cm-3 . Overall board density ranges from 1,10- 1,15 g cm-3 . A mixture of polyester-coconut fiber composite board with sorghum bagasse powder can increase the value of physical, mechanical and impact properties. The particle content has significant effect on the impact strength of the board, therefore it can increase the strength value of the board. Particle size has no significant effect on the physical, mechanical and impact properties of the board. Composite boards with a high percentage of particle content can increase the tensile and impact strength values of the boards.
Keyword: olyester, sorghum, coconut fiber, composite board

Judul: igenvalues and Eigenvectors of Tridiagonal Matrix with Non Constant and Recurrent Diagonal Entries.
Abstrak: Matriks tridiagonal adalah suatu matriks yang mempunyai entri-entri bernilai nol kecuali pada diagonal utama, di bawah diagonal utama (subdiagonal) dan di atas diagonal utama (superdiagonal). Entri pada diagonal utama tidak konstan dan berulang. Setiap entri pada matriks tridiagonal ini adalah bilangan kompleks. Dalam karya ilmiah ini, akan dibuktikan 3 teorema untuk menentukan nilai eigen dengan 2 kasus dan 1 teorema untuk menentukan vektor eigen. Teorema pertama menentukan polinomial karakteristik dari matriks tridiagonal. Polinomial karakteristik dari matriks tridiagonal tersebut digunakan untuk menentukan nilai eigen pada teorema kedua dan ketiga serta menentukan vektor eigen pada teorema keempat
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