Judul: Karakteristik Beton Ringan Ramah Lingkungan Berbahan Arang Hidro Serat Kenaf dan Arang Aktif Batang Kenaf
Abstrak: Beton ringan banyak diapilikasikan diberbagai infrastuktur bangunan. Dalam aplikasinya beton sangat rentan terjadinya pecah ataupun retakan, akibatnya kekuatan material beton menurun, sehingga dapat diminimalisir menggunakan bahan alam dari serat tumbuhan yaitu tanaman kenaf. Penggunaan bahan lainnya berupa arang aktif dari tanaman berpotensi untuk menjerap polutan berbahaya di udara melalui skema arang aktif. Tujuan dari penelitian ini adalah menganalisa pengaruh suhu aktivasi terhadap sifat arang aktif dan daya jerap polutannya, menganalisa komposisi yang tepat dari komposit semen dengan penambahan arang hidro serat kenaf dengan penambahan arang aktif batang kenaf terhadap pemulihan retak secara mandiri dan kemampuan menjerap polutan beton ringan. Penelitian ini terdiri dari persiapan bahan baku, proses karbonisasi hidrotermal, pembuatan arang aktif dan pembuatan beton ringan, kemudian dikarakterisasi meliputi analisis proksimat, daya jerap polutan, sifat mekanis beton serta dilakukan analisis pemulihan retak pada beton. Suhu aktivasi berpengaruh nyata terhadap kadar abu, zat terbang, karbon terikat dan daya jerap benzena. Semua arang aktif memenuhi syarat mutu arang aktif teknis yang ditetapkan standar SNI 06-3730-1995 untuk parameter kadar air, kadar zat terbang, kadar karbon terikat namun hanya sebagian arang aktif memenuhi syarat untuk kadar abu. Arang aktif terbaik terdapat pada suhu 600 ○C. Variasi serat kenaf tidak berpengaruh nyata terhadap kerapatan, kuat tekan, MOE, MOR dan daya jerap polutan terhadap formaldehida dan kloroform, sedangkan variasi arang hidro serat kenaf berpengaruh nyata terhadap daya jerap benzena dan amonia. Pemulihan retak secara mandiri pada beton ringan melalui siklus basah-kering mengalami pemulihan 70,38-100%. Komposisi terbaik beton ringan terdapat pada penambahan arang hidro serat kenaf 1,5% dan arang aktif batang kenaf 3%., Lightweight concrete is widely applied in various building infrastructures. In its application, concrete is very susceptible to breakage or cracks, as a result the strength of the concrete material decreases, so it can be minimized using natural materials from plant fibers, namely kenaf plants. The use of other materials in the form of activated charcoal from plants has the potential to absorb harmful pollutants in the air through the activated charcoal scheme. The purpose of this study was to analyze the effect of activation temperature on the properties of activated charcoal and its pollutant adsorption capacity, analyze the correct composition of cement composites with the addition of kenaf hydro-fiber charcoal with the addition of activated charcoal from kenaf stems on crack recovery independently and the ability to absorb pollutants in lightweight concrete. This research consisted of preparation of raw materials, hydrothermal carbonation process, manufacture of activated charcoal and manufacture of lightweight concrete, then characterized by proxymate analysis, pollutant adsorption capacity, mechanical properties of concrete and analysis of crack recovery in concrete. The activation temperature significantly affected the ash content, volatile matter, bound carbon and the adsorption capacity of benzene. All activated charcoal met the technical activated charcoal quality requirements set by the SNI 06-3730-1995 standard for parameters of moisture content, volatile matter content, bound carbon content, but only some activated charcoal met the requirements for ash content. The best activated charcoal is found at a temperature of 600 ○C. Variations in kenaf fiber did not significantly affect density, compressive strength, MOE, MOR and pollutant adsorption capacity
Keyword: lightweight concrete, kenaf plant, hydro charcoal, activated charcoal

Judul: Characteristics of Kenaf Fiber Charcoal (Hibiscus cannabinus L.) With Pyrolysis Carbonization
Abstrak: Serat kenaf merupakan serat yang cukup potensial untuk dijadikan sebagai bahan baku arang aktif melalui proses karbonisasi pirolisis. Proses ini lebih dipilih karena waktu proses yang digunakan relatif lebih singkat dan efisien dibandingkan dengan karbonisasi hidrotermal. Namun, ada beberapa hal yang harus dievalusi untuk menganalisis karakteristik arang pirolisis serat kenaf hasil karbonisasi pirolisis serta menganalisis pengaruh suhu dan waktu dalam proses karbonisasi pirolisis terhadap sifat arang serat kenaf dan daya jerap polutannya. Proses karbonisasi pirolisis dilakukan pada suhu 175 oC, 200 oC, 225 oC dengan waktu selama 3, 4, dan 5 jam. Karakteristik yang dianalisis dalam penelitian ini antara lain komponen kimia dan analisis proksimat dari serat kenaf, sedangkan dari arang yang dihasilkan, dianalisis rendemen, kadar air, kadar abu, kadar zat terbang, kadar karbon terikat, daya jerap iodin, dan daya jerap polutan (amonia, kloroform, formaldehida, dan benzena). Hasil penelitian menunjukkan interaksi antara suhu dan waktu karbonisasi pirolisis berpengaruh nyata terhadap kadar zat terbang, karbon terikat, daya jerap amonia dan daya jerap kloroform. Namun, interaksi antara suhu dan waktu karbonisasi pirolisis tidak memberikan pengaruh yang nyata pada daya jerap benzena, kadar air, dan kadar abu. Arang pirolisis terbaik didapatkan pada suhu 200oC selama 5 jam dengan daya jerap iodin sebesar 148,19 mg/g, Kenaf fiber is a fiber that has potential to be used as raw material for activated charcoal through the pyrolysis carbonization process. This process is preferred because the processing time used is relatively shorter and more efficient than hydrothermal carbonization. However, there are several things that must be evaluated to analyze the characteristics of the pyrolysis charcoal of kenaf fiber asa result of pyrolysis carbonization and to analyze the effect of temperature and time in the pyrolysis carbonization process on the characteristics of the kenaf fiber charcoal and its pollutant adsorption capacity. The pyrolysis carbonization process was carried out at temperatures of 175 oC, 200 oC, 225 oC for 3, 4, and 5 hours. The characteristics analyzed in this study included chemical components and proximate analysis of kenaf fiber, while the resulting charcoal was analyzed for yield, moisture content, ash content, volatile matter content, bound carbon content, iodine adsorption capacity, and pollutant adsorption capacity (ammonia, chloroform, formaldehyde, and benzene). The results showed that the interaction between temperature and time of pyrolysis carbonization had a significant effect on volatile matter, bound carbon, ammonia adsorption capacity and chloroform adsorption capacity. However, the interaction between temperature and time of pyrolysis carbonization did not have a significant effect on the adsorption capacity of benzene, moisture content, and ash content. The best pyrolysis charcoal was obtained at 200oC for 5 hours with an iodine adsorption capacity of 148.19 mg/g
Keyword: Arang pirolisis, daya jerap iodin, Daya jerap polutan, Karbonisasi pirolisis, Serat kenaf, Pyrolysis charcoal, Iodine adsorption capacity, Pollutant adsorption capacity, Pyrolysis carbonization, Kenaf fiber

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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