Judul: Senyawa Penciri Damar Mata Kucing untuk Pembaruan Parameter Standar Nasional Indonesia
Abstrak: The best quality cat eyes dammar that has high price in market is produced by Shorea javanica. Indonesia National Standard (SNI) 2900:1999 classifies the grade of cat eyes dammar based on parameters of softening point, acid number, ash content, toluene insoluble matter content, solution properties in 50% toluene, and solution properties in 20% toluene. The grades of cat eyes dammar are A, B, C, D, E, A/D, A/E, and Bubuk. Most of the parameters cannot be used to classify this commodity distinctly so that a quantitative chemical parameter is needed. The results showed that most of the SNI parameters have low agreement with the grades as determined by sellers. To obtain chemical profile, toluene extracts for all sample were analyzed by gas chromatography mass spectrometer. α-Copaene was identified in all cat eyes dammar samples and linearly correlated with the dammar grades. The same result was showed in resin content. These results were potencial to become new parameter for SNI revising.
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Judul: Sifat Fisiko-Kimia Damar Mata Kucing (Shorea javanica K. et V.) Hasil Klasifikasi Mutu di Pasar Domestik
Abstrak: Hutan alam di Indonesia didominasi oleh famili Dipterocarpaceae, salah satunya adalah pohon Shorea javanica. Pohon tersebut menghasilkan resin dengan mutu yang sangat tinggi dan dikenal sebagai damar mata kucing. Damar mata kucing asal Indonesia telah lama menjadi komoditi perdagangan. Walaupun mutu suatu bahan unsur yang sangat penting dalam perdagangan, namun penentuan mutu damar mata kucing di pasar domestik masih berdasarkan uji visual yaitu kebersihan, warna, dan ukuran bongkahan saja. Oleh sebab itu sangat dimungkinkan damar yang diklasifikasikan secara visual sebetulnya memiliki kandungan fisiko-kimia yang hampir sama. Penelitian ini bertujuan untuk mengetahui sifat fisiko-kimia damar mata kucing dari berbagai klasifikasi mutu secara visual (mutu A, B, C, D, E, dan Abu) yang berasal dari tiga lokasi (PT. Bintang Kazha Gemilang, Krui, dan PT. Winas Guna Mustika). Pengujian dilakukan dengan pengamatan secara visual terhadap warna dan ukuran bongkahan, serta pengujian laboratoris untuk parameter bahan tidak larut dalam toluena (kadar kotoran), kadar air, kadar abu, bilangan asam, bilangan penyabunan, dan titik lunak. Hasil pengujian menunjukkan bahwa damar mata kucing dengan mutu yang tinggi berdasarkan klasifikasi secara visual, berkecenderungan memiliki nilai kadar air, kadar abu, bilangan asam, bilangan penyabunan, titik lunak, dan bahan tidak larut dalam toluena yang rendah. Akan tetapi, penentuan mutu damar mata kucing secara visual masih bersifat subjektif, karena terbukti damar mata kucing mutu A, B, dan C yang dikelompokkan secara visual memiliki ukuran bongkahan yang berbeda, namun menunjukkan sifat fisiko-kimia yang hampir sama dan dapat dikelompokkan ke dalam satu klasifikasi mutu (mutu A).
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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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