Judul: Produksi Filamen Komposit PVA-Alginat dengan Selulosa dari Tandan Kosong Kelapa Sawit
Abstrak: Selulosa merupakan polimer alami terbarukan yang ketersediaannya melimpah di bumi dan salah satu sumbernya tersedia pada tandan kosong kelapa sawit (TKKS). TKKS merupakan salah satu biomassa yang dihasilkan dari produksi minyak sawit (CPO). Selulosa diisolasi melalui tahap deliginifikasi dan bleaching. Selulosa TKKS dapat dimanfaatkan sebagai bahan baku pembuatan filamen dimana selulosa dicampur dengan polivinil alkohol (PVA) dan alginat. Dalam penelitian ini, filamen komposit selulosa-PVA-alginat diproduksi melalui metode wet spinning dengan CaCl2 sebagai larutan koagulan. Dilakukan observasi efek formulasi filamen dan konsentrasi CaCl2 terhadap sifat mekanik, morfologi, kristalinitas, dan termal filamen. Hasil yang didapatkan menunjukkan peningkatan konsentrasi selulosa menyebabkan stabililitas termal yang baik, kristalinitas tinggi, meskipun morfologi permukaan filamen menjadi lebih kasar. Filamen dengan penambahan selulosa (5, 10, dan 15%) memberikan hasil yang signifikan terhadap sifat mekanik filamen, khususnya kuat tarik. Peningkatan konsentrasi CaCl2 menghasilkan filamen dengan stabilitas termal yang baik, namun konsentrasi CaCl2 yang lebih rendah menghasilkan filamen dengan kuat tarik yang lebih baik.
Keyword: filamen, koagulan, selulosa, tandan kososng kelapa sawit, wet spinning

Judul: Analisis Karakteristik Sifat Fisis Filamen Nanoselulosa-Alginat-PVA Untuk Aplikasi 3D Bioink
Abstrak: Nanoselulosa merupakan karbohidrat yang sangat melimpah di alam. Selain ramah lingkungan, nanoselulosa memiliki sifat biokompatibel, biodegradable, dan printability sehingga dapat diaplikasikan sebagai bahan baku 3D bioink. Matrix PVA/alginat dapat diformulasikan dengan selulosa sebagai reinforcing agent. Penelitian ini bertujuan untuk menganalisis pengaruh konsentrasi nanoselulosa terhadap sifat fisis filamen yang dibuat menggunakan metode wet spinning. Metode yang digunakan dalam penelitian ini adalah meta-analisis dengan pendekatan regresi linear sederhana. Pengolahan data dilakukan dengan pencarian nilai koefisien determinasi (R2), p-value, serta koefisien kemiringan kurva. Melalui model regresi linear sederhana, kekuatan mekanis material dari hasil uji tensile strength dianalisis pada penelitian ini. Selain itu, derajat kristalinitas dan stabilitas termal juga dianalisis. Spektra FTIR filamen dianalisis berdasarkan intensitas, shifting wave number, dan gugus fungsi. Morfologi permukaan dan cross section filamen diamati citranya melalui hasil uji SEM. Diameter partikel ikut serta diulas., Nanocellulose is a carbohydrate that is very abundant in nature. In addition to being environmentally friendly, nanocellulose has biocompatible, biodegradable, and printability properties so that it can be applied as a raw material for 3D bioink. Matrix PVA/alginate can be formulated with cellulose as a reinforcing agent. This study aims to analyze the effect of nanocellulose concentration on the physical properties of filaments made using the wet spinning method. The method used in this study is a meta-analysis with a simple linear regression approach. Data processing was carried out by searching for the coefficient of determination (R2), p-value, and the slope coefficient of the curve. Through a simple linear regression model, the mechanical strength of the material from the tensile strength test results was analyzed in this study. In addition, the degree of crystallinity and thermal stability were also analyzed. Filament FTIR spectra were analyzed based on intensity, shifting wave number, and functional groups. The surface morphology and the cross section of the filament were observed through the SEM test results. The particle diameter was also reviewed.
Keyword: Meta-analysis, nanocellulose, PVA-alginate, wet spinning

Judul: A Continuous Vaccination Strategy in the SVIR Epidemic Model
Abstrak: Vaccination is conducted to minimize the spread of a disease. The vaccination is usually done several times within a fixed time interval. In the SVIR model, it is assumed that individuals do not get immediate immunity following a vaccination program. So according to process of vaccination on SVIR model, there are two strategies, i.e. the continuous vaccination strategy (CVS) and the pulse vaccination strategy (PVS). In this study, only the CVS strategy in epidemic model SVIR is considered. Results of the study indicate that dynamics of the CVS system depends on the basic reproductive number. If the basic reproductive number is less than one, then the disease-free fixed point is asymptotically stable. It means that the disease will eventually disappear from the population. Conversely, if the basic reproductive number is greater than one, then the endemic fixed point is asymptotically stable, which means that the disease will remain exist in the population. Simulation result shows that the vaccination would minimize the spread of disease by reducing the basic reproductive number. If the time for the vaccinated recipients to obtain the immunity, as well as a possibility of vaccinated recipients to be infected are neglected, then the disease will be eradicated. This condition is called an over-evaluating effect of vaccination.
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