Judul: Surface Characteristics of Banana Stem Fiber with Delignification Treatment
Abstrak: Penelitian ini bertujuan untuk mengetahui pengaruh perlakuan delignifikasi dengan variasi larutan pemasak terhadap komposisi kimia serat batang pisang serta mengetahui perubahan sifat permukaan serat batang pisang. Pengujian komposisi kimia menggunakan metode TAPPI menunjukkan serat batang pisang delignifikasi NaOH konsentrasi 10% adalah sampel dengan komposisi kimia terbaik. Hal ini ditunjukkan dengan adanya penurunan kadar lignin sebesar 51,88% dan peningkatan kadar alfa selulosa sebesar 36,36% dari serat perlakuan kontrol. Hasil pengujian TAPPI linear dengan citra FTIR pada sampel delignifikasi NaOH konsentrasi 10%. Pengujian Surface Free Energy (SFE) tertinggi ditunjukkan pada sampel delignifikasi NaOH konsentrasi 10%. Peningkatan nilai SFE pada sampel tersebut menunjukkan adanya penurunan sifat hidrofobisitas pada permukaan serat. Nilai interfacial energy saat serat batang pisang berinteraksi dengan air lebih besar karena adanya readsorpsi air. Nilai adhesive energy serat batang pisang yang tinggi menyebabkan komponen zat cair menyerap pada permukaan sampel secara alami., This study aims to determine the effect of the delignification treatment using various solutions on the chemical composition of banana stem fiber and to determine changes in the surface properties of banana stem fiber. Results of TAPPI method test showed that the 10% concentration of NaOH solution produced the best chemical composition, this was indicated by a decrease in lignin content by 51,88% and an increase in alpha cellulose content by 36,36% compared to the control fiber. TAPPI test results were linear with FTIR analysis on 10% concentration of NaOH delignification sample. The highest Surface Free Energy (SFE) value was found in sample with the best chemical composition. An increase in the SFE value indicated a decrease in the hydrophobicity of the fiber surface. The value of the interfacial energy when the samples interacts with water are greater because of water readsorption. The high adhesive energy value of the samples causes the liquid component to adsorb on the surface of the samples naturally.
Keyword: banana stem fiber, delignification, FTIR, Surface Free Energy (SFE)

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: 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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