Judul: Effect of EFB Elements on Pulp and Viscose as Raw Materials for Viscose Rayon Staples
Abstrak: Serat viskosa merupakan serat semi sintetis yang berasal dari proses regenerasi selulosa dengan dissolving pulp sebagai bahan baku. TKKS memiliki kandungan selulosa yang cukup tinggi sehingga dalam penelitian ini akan diolah sebagai dissolving pulp. Tujuan penelitian ini adalah mengetahui bagian TKKS terbaik yang dapat menghasilkan pulp dan viscose sesuai dengan standar. Penelitian ini juga bertujuan mengetahui waktu terbaik dalam proses aging dan konsentrasi CS2 yang dapat menghasilkan viscose. Proses pembuatan pulp menggunakan metode prahidrolisis kraft karena memiliki kelebihan dapat menghasilkan pulp dengan kemurnian tinggi. Dissolving pulp yang didapatkan selanjutnya diolah menjadi bahan baku pembuatan larutan viscose. Viscose merupakan larutan yang berasal dari pulp hasil aging kemudian diberikan CS2 membentuk selulosa xantat yang selanjutnya dilarutkan. Pengujian yang dilakukan berupa pengujian kimia bahan baku dan dissolving pulp, pengujian XRD, SEM-EDX, dan pengujian FTIR. Pada proses aging dilakukan variasi waktu dan pada proses xantasi konsentrasi CS2 divariasikan. Hasil penelitian menunjukkan TKKS stalk menghasilkan pulp terbaik yang sesuai dengan standar SNI. Pembuatan viscose dari kedua sampel menunjukkan bahwa pulp TKKS stalk menghasilkan viscose sesuai dengan standarisasi., In the cellulose regeneration process, the basic material for viscose fiber is dissolving pulp. OPEFB will be used as dissolving pulp because of its high cellulose content. This research aims to discover industry-standard OPEFB components for pulp and viscose production. Viscosity can also be produced by determining the ideal time of aging and the concentration of CS2 that produces it. The kraft prehydrolysis method is used in the pulp producing process because it produces high-purity pulp. Raw materials for viscose solution are made from the dissolving pulp. To make cellulose xanthate, aged pulp is mixed with CS2 to generate viscose, which is then dissolved in water. Raw materials and dissolving pulp are subjected to chemical testing, as well as XRD, SEM-EDX, and FTIR testing. In the viscose process, aging time and CS2 concentration are varied. In compliance with SNI criteria, OPEFB stalk pulp was found to provide the best pulp. Both samples showed OPEFB stalk pulp met viscose production standards.
Keyword: Cellulose, Dissolving Pulp, OPEFB, Viscose

Judul: Synthesis and Characterization of Viscose Made from OPEFB Fiber as a Semiconductor Material
Abstrak: Viskosa merupakan serat semi sintetis yang berasal dari proses regenerasi selulosa. Dalam penelitian ini, kandungan alfa selulosa TKKS yang tinggi diolah sebagai bahan baku dissolving pulp. Pembuatan pulp dilakukan menggunakan metode prahidrolisis kraft dengan variasi konsentrasi alkali aktif pada tahap pemasakan yaitu 15%, 20%, dan 25%, selanjutnya pulp diolah menjadi alkali selulosa kemudian dibentuk menjadi viskosa bersifat selulosa xantat. Penelitian ini bertujuan untuk mengetahui konsentrasi alkali aktif terbaik pada tahap pemasakan yang dapat menghasilkan pulp dan viskosa optimum. Pengujian yang dilakukan berupa pengujian kimia dissolving pulp, pengujian sifat listrik dengan LCR meter dan pengujian sifat permukaan dengan perhitungan energi bebas permukaan (SFE) viskosa. Hasil penelitian menunjukkan konsentrasi alkali aktif 25% menghasilkan pulp terbaik sesuai dengan SNI 938:2017. Konduktivitas listrik dan resistivitas yang dihasilkan dari ketiga sampel viskosa menunjukkan material yang bersifat semikonduktor. Variasi cairan uji SFE dengan air dan FFA memberikan sifat hidrofilik pada permukaan viskosa TKKS., Viscose is a semi-synthetic fiber obtained from a cellulose regeneration process. In this study, OPEFB which has a high alpha cellulose content, was processed as a raw material for dissolving pulp. The pre-hydrolysis kraft method is used to produce pulp with varying concentrations of active alkali used during the cooking stage are 15%, 20%, and 25%, which is subsequently processed into alkaline cellulose and converted into viscose with cellulose xanthate properties. The objective of this study is to determine the best concentration of active alkali in the cooking stage that can produce optimal pulp and viscose. The tests were carried out in the chemical testing of dissolving pulp, testing the electrical properties with an LCR meter and testing the surface properties by calculating the surface free energy (SFE) of OPEFB viscose. The results showed that the 25% active alkali concentration produced the best pulp according to SNI 938:2017. The electrical conductivity and resistivity of the three viscose samples show that the material is semiconducting. Variation of the SFE test liquid with water and FFA gave hydrophilic properties on the OPEFB viscose surface.
Keyword: Dissolving Pulp, OPEFB, Semiconductor, Surface Free Energy, Viscose

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