Judul: The Profile of Crude Oils of Indonesia
Abstrak: Dari dua belas karakteristik umum minyak bumi yang dianalisis ternyata terdapat empat faktor penciri profil minyak bumi Indonesia, yaitu faktor Penentu Suhu Panas, faktor Penciri Minyak Bumi, faktor Kekentalan Kinematik dan Karakteristik Uop, serta faktor Total Angka Asam. Berdasarkan keempat faktor tersebut, minyak bumi Indonesia dapat dipilah kedalam empat kelompok. Kelompok pertama adalah kelompok minyak bumi dengan nilai gravitasi API, kadar. karbon, dan tekanan uap Reid yang sangat tinggi; kelompok kedua memiliki nilai gravitasi spesifik, residu karbon Konradson, dan kadar belerang yang sangat tinggi; kelompok ketiga memiliki nilai titik tuang, kadar lilin, kekentalan kinematik, faktor karakteristik uop, kadar garam dan total angka asam yang sangat tinggi; sedangkan kelompok keempat adalah kelompok minyak bumi netral.
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Judul: Kajian mutu minyak sawit kasar dan analisis karakterisrik olein serta stearin sebagai hasil fraksinasinya
Abstrak: Crude Palm Oil (CPO) is a vegetable oil obtained from oil palm fruit extraction process (Elais guinneensis) with reddish orange colour. Standards applicable in Indonesia for CPO released by the National Standardization Agency stated in the document SNI 01-2901-2006 include free fatty acids (maximum 0.5%), moisture and impurities (maximum 0.5%), iodine value (50-55 g yodium/100 g), and reddish orange. In addition to chemical characteristics, other characteristics CPO such as carotene content and DOBI are also important to know as additional data. To increase the value-added palm oil, fractionated CPO usually produces two components, namely liquid olein and stearin with solid form. This study aims to obtain quality data CPO based on SNI-01-2901-2006, carotene, DOBI, and investigate the characteristics of the olein and stearin. Analysis of five types of CPO samples show different data on each CPO character. The result showed moisture content and impurities 0.33-5.39%, free fatty acids 3.84-5.88%, iodine value 50.38-54.15 g yodium/100 g, carotene content 428.28-815.56 ppm, and DOBI 1.34-3.11. The variation can be influenced by several factors including the processing of each palm oil mill and palm fruit oil condition of maturity that will be processed into crude palm oil. Fractination process carried out by melted CPO at 50 °C. The melted CPO was cooled until 15 °C with cooling rate 5 °C/30 minutes. Then crystallization carried out at 12°C for 16 hours. Separation was done by vacuum filter to get olein and stearin. The Olein and stearin were produced from fractination were analyzed. The results showed iodine value, slip melting point, and carotene content for olein consecutive 57.75-60.02 g yodium/100 g, 18.33-24 °C, and 438-536 ppm. While for stearin iodine value 34.95-42.32 g yodium/100 g, slip melting point 50.33-52 °C, and carotene content 215-276 ppm. Olein and stearin have very different characteristics.
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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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