Judul: Modification of the Surface Properties of Oil Palm Empty Leaves (EFB) using the Delignification Method
Abstrak: Delignifikasi merupakan tahap awal yang bertujuan untuk mengurangi komposisi kimia non-selulosa di dalam serat TKKS. Delignifikasi dapat memutuskan ikatan non-selulosa dan melarutkan impuritas agar selulosa menjadi lebih mudah diurai. Tujuan penelitian ini dilaksanakan untuk memperoleh serat panjang TKKS dengan metode delignifikasi dan mengaplikasikannya dalam kain nonwoven serta mendapatkan kajian sifat mekanik. Proses pembuatan serat menggunakan pra-perlakuan sodium klorit-asam asetat (SC-AA) dan alkaline peroxide (AP), kemudian dilakukan pengujian komponen kimia menggunakan TAPPI. Hasil pengujian Sampel dikarakterisasi menggunakan alat TGA, FTIR, ASTM D 5035 dan ASTM D 5587. Hasil penelitian menunjukkan bahwa, berdasarkan uji termal (TGA) Sampel A6 memiliki kemampuan termal lebih baik dengan degradasi massa yang kecil 29% karena perlakuan AP mampu degradasi impuritas dan komposisi non-selulosa lebih tinggi dibandingkan perlakuan SC-AA. Sedangkan pada uji FTIR gugus fungsi pada bilangan gelombang 1030 cm-1 (C-O), 2300 cm-1 (O-H), 2900 cm-1 (C-H) menunjukkan terjadi penurunan persen transmitansi pada sampel A4 dan A6 dibandingkan kontrol. Hasil uji tarik dan sobek serat TKKS yang terbaik berdasarkan perlakuan alkaline peroxide yaitu pada nonwoven 4 lapis, semakin besar lapisannya maka kekuatan sobek dan tarik semakin tinggi. Delignifikasi terbaik adalah sampel alkaline peroxide (180 menit) dan berdasarkan uji mekanik serat TKKS nonwoven lapisan 4 dengan gramassi 1700 g/m2., Delignification is an initial step that aims to reduce the chemical composition of non-cellulose in the OPEFB fibers. Delignification can break non- cellulose bonds and dissolve impurities to make cellulose easier to break down. The purpose of this study was to obtain long fiber OPEFB by delignification method and apply it to non-woven fabrics and obtain a study of its mechanical properties. The fiber manufacturing process uses pre-treatment of sodium chlorite-acetic acid (SC-AA) and alkaline peroxide (AP), then testing the chemical components using TAPPI. Test results The samples were characterized using TGA, FTIR, ASTM D 5035 and ASTM D 5587 tools. The results showed that, based on the thermal test (TGA) Sample A6 had a better thermal ability with a small mass degradation of 29% because AP treatment was able to degrade impurity and non-cellulose composition was higher than SC-AA treatment. Whereas in the functional group FTIR test at wave numbers 1030 cm-1 (C-O), 2300 cm-1 (O-H), 2900 cm-1 (C-H) showed a decrease in the percentage of transmittance in samples A4 and A6 compared to controls. The best results of the tensile and tear test for OPEFB fibers based on alkaline peroxide treatment, namely on 4-layer nonwovens, the larger the layer, the higher the tear and tensile strength. The best delignification is alkaline peroxide sample (180 minutes) and based on mechanical test of 4 layer nonwoven OPEFB fibers with gramassiere 1700 g/m2.
Keyword: Alkaline peroxide (AP), Delignification, Chemical components, Nonwoven, OPEFB fibers, Sodium chlorite-acetic acid (SC-AA)

Judul: Delignification of Oil Palm Empty Fruit Bunches using Ozone Microbubble Technique
Abstrak: Proses delignifikasi biomassa berlignoselulosa umumnya masih banyak menggunakan bahan kimia seperti klorin yang limbahnya berbahaya bagi lingkungan. Mikrogelembung ozon merupakan salah satu metode yang ramah lingkungan untuk mengurangi kadar lignin dalam biomassa. Penelitian ini bertujuan menetapkan kondisi terbaik berdasarkan parameter selektivitas delignifikasi (nisbah selulosa/lignin) pada proses ozonolisis dan mencirikan serat berdasarkan kriteria serat untuk pulp dan kertas. Serat tandan kosong kelapa sawit (TKKS) didelignifikasi pada pH 3 (larutan asam oksalat), pH netral (akuades), dan pH 10 (larutan NaOH) selama 30, 45 dan 60 menit dengan laju alir ozon 3 L menit-1. Perlakuan ozonolisis terbaik diperoleh pada kondisi pH asam selama 60 menit yang berhasil mendegradasi lignin dari 11,4% menjadi 7,0% dengan selektivitas delignifikasi 8,86. Serat TKKS termasuk serat kelas III untuk pulp kertas dan proses ozonolisis tidak mengubah kelasnya. Ozonolisis serat TKKS memberikan proses delignifikasi yang lebih hemat waktu dan energi serta ramah lingkungan., The delignification process of lignocellulosic biomass generally still uses many chemicals, such as chlorine, which produces hazardous waste for the environment. Ozone microbubbles are an environmentally friendly method for reducing lignin content in biomass. This study aims to determine the best conditions based on delignification selectivity (cellulose/lignin ratio) in the ozonolysis process and characterize the fiber characteristics based on fiber criteria for pulp and paper. The oil palm empty fruit bunch (OPEFB) fibers were delignified at pH 3 (oxalic acid solution), neutral pH (distilled water), and pH 10 (NaOH solution) for 30, 45 and 60 minutes with an ozone flow rate of 3 L min-1. The best ozonolysis treatment was obtained under acidic pH conditions for 60 minutes which succeeded in degrading the lignin content from 11,4% to 7,0% with a delignification selectivity value of 8,86. OPEFB fiber was classified as class III fiber for paper pulp, and the ozonolysis process does not change its class. The OPEFB fiber ozonolysis process provide a delignification process that saves time and energy as well as is environmentally friendly.
Keyword: delignification, delignification selectivity, microbubble, oil palm empty fruit bunches, ozone

Judul: Dynamical System of Hepatitis B in Three Groups with Vaccination
Abstrak: The aim of this study is to modify the hepatitis B transmission model in three age groups involving vaccination from the model conducted by Zhoe and Zhang.The method used is to analyze the stability of the fixed point and its basic reproduction number (R_0). Performed stability analysis and numerical simulation to see population dynamics. Next, a sensitivity analysis of the parameters was carried out to see its effect on R_0. From the analysis obtained two fixed points, namely non-endemic and endemic fixed points. Non-endemic fixed points are locally asymptotically stable if R_0 <1 Meanwhile, the endemic fixed point is locally asymptotically stable if R_0 > 1. Hepatitis vaccination affects the number of susceptible population, because the more successful the vaccination, the smaller the number of susceptible populations so that the smaller the population will be infected.
Keyword: Dynamic, Hepatitis B, Vaccine, Mathematical model