Judul: Characterization of Carbon Nanoparticles (C-Dots)  Originated from Palm Oil Waste
Abstrak: Peningkatan produktivitas kelapa sawit meningkatkan limbah yang dihasilkan. Penelitian ini mengkarakterisasi C-dots dari Tandan Kosong Kelapa Sawit (TKKS) dan pelepah dengan agen pasivasi menggunakan metode hidrotermal, serta menganalisis efektivitas C-dots dari TKKS dan pelepah kelapa sawit sebagai penjerap zat warna dan logam berat, termasuk pendeteksi logam berat pada air. Penelitian ini meliputi preparasi sampel, sintesis C-dots, adsorpsi Pb(II) dan zat warna MB, uji sensor ion logam Pb2+ dan karakterisasi C-dots. C-dots dari TKKS dan pelepah kelapa sawit formula 1 dan formula 3 memiliki rendemen tertinggi. Uji sensor logam berat Pb²? menunjukkan variasi intensitas fluoresensi. Adsorpsi Pb(II) oleh C-dots meningkat seiring waktu kontak. Spektrum emisi fluoresensi menunjukkan C-dots TKKS formula 2 (asam sitrat-urea) dan C-dots pelepah formula 3 (urea) memiliki gelombang emisi maksimum, sedangkan formula 4 (air) memiliki panjang gelombang emisi terendah pada TKKS maupun pelepah kelapa sawit. Pola serapan UV-Vis menunjukkan C-dots TKKS formula 1 (asam sitrat-NH4OH) memiliki absorbansi tertinggi. Spektrum FTIR menunjukkan puncak serapan dan gugus fungsi pada C-dots TKKS dan pelepah kelapa sawit., Increasing palm oil productivity increases the waste produced. This study characterizes C-dots from Empty Palm Oil Bunches (TKKS) and fronds with passivation agent using hydrothermal method, and analyzes the effectiveness of C-dots from TKKS and palm fronds as a sorbent of dyes and heavy metals, including heavy metal detection in water. This research includes sample preparation, C-dots synthesis, adsorption of Pb(II) and MB dye, Pb2+ metal ion sensor test and C-dots characterization. C-dots from TKKS and palm fronds formula 1 and formula 3 have the highest yield. The Pb²? heavy metal sensor test showed variation in fluorescence intensity. Adsorption of Pb(II) by C-dots increased with contact time. Fluorescence emission spectra showed that TKKS C-dots formula 2 (citric acid-urea) and palm frond C-dots formula 3 (urea) had the maximum emission wavelength, while formula 4 (water) had the lowest emission wavelength in both TKKS and palm frond. The UV-Vis absorption pattern shows that the TKKS C-dots formula 1 (citric acid-NH4OH) has the highest absorbance. FTIR spectrum shows the absorption peaks and functional groups in the C-dots of TKKS and oil palm fronds.
Keyword: C-dots, fluoresensi, hidrotermal, limbah, kelapa sawit, C-dots, fluorescence, hydrothermal, waste, palm oil

Judul: Sintesis Nanopartikel Karbon dari Limbah Padat Kelapa Sawit Secara Hidrotermal dan Mikrogelombang
Abstrak: Nanopartikel karbon (C-dot) merupakan nanomaterial berfluoresens yang berukuran kurang dari 10 nm. C-dot dapat disintesis dari berbagai bahan yang memiliki kandungan karbon yang tinggi, seperti limbah kelapa sawit. Untuk meningkatkan fluoresensi C-dot dapat ditambahkan urea sebagai agen pasivasi. Penelitian ini bertujuan menyintesis dan mencirikan C-dot dari limbah padat kelapa sawit, yaitu bungkil, tandan kosong, dan cangkang dengan tambahan dan tanpa tambahan urea menggunakan metode hidrotermal dan mikrogelombang. Hasilnya menunjukkan bahwa sintesis C-dot menggunakan metode hidrotermal lebih baik daripada mikrogelombang dan tambahan urea meningkatkan intensitas pendaran C-dot. Puncak emisi maksimum yang dihasilkan C-dot dari bungkil tanpa dan dengan tambahan urea berturut-turut adalah 505 nm dan 503 nm untuk metode hidrotermal, serta 512 nm dan 511 nm untuk metode mikrogelombang. Jadi, bungkil sawit merupakan sumber C-dot terbaik. Spektrum infra-merah menunjukkan keberadaan gugus fungsi –OH, N-H, C=O, C-H, dan CH2 pada permukaan C-dot. Analisis menggunakan mikroskop elektron payaran energi dispersif sinar-X menunjukkan kandungan unsur C, N, O, Si, dan S.
Keyword: C-dot, fluorescent, hydrothermal, microwave, palm oil waste

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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