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: Optimization of C-dot Nanoparticle Emissions from Palm Kernel Meal by Hydrothermal Method
Abstrak: Nanopartikel karbon dot (C-dot) merupakan nanopartikel berfluoresens berdimensi nol dengan ukuran kurang dari 10 nm. Penelitian sebelumnya menunjukkan bahwa C-dot yang disintesis dari bungkil kelapa sawit menggunakan metode hidrotermal memiliki intensitas emisi tertinggi di antara limbah kelapa sawit lainnya. Penelitian ini bertujuan menentukan kondisi optimum sintesis C-dot dari bungkil kelapa sawit secara hidrotermal dengan variasi suhu sintesis, waktu sintesis, dan konsentrasi melalui variasi volume pelarut. Rendemen C-dot tertinggi sebesar 9,30% dicapai pada suhu 200 ? selama 24 jam dengan 80 mL pelarut. Kondisi optimum berdasarkan intensitas emisi C-dot terbaik dicapai pada suhu 200 ? selama 8 jam dengan 40 mL pelarut. Hasil analisis spektrofotometer UV-Vis menunjukkan terdapat pergeseran panjang gelombang puncak serapan. Terdapat peningkatan intensitas emisi C-dot yang disintesis dari suhu 150 °C hingga 200 °C. Namun, intensitas emisi menurun pada suhu 250 °C. Spektrum FTIR mengindikasikan adanya gugus fungsi yang terdapat pada C-dot, seperti O-H dan C=O. Hasil analisis menggunakan PSA menunjukkan ukuran partikel yang besar dan distribusi ukuran partikel dengan homogenitas yang rendah., Carbon dot nanoparticles (C-dot) are zero-dimensional fluorescent nanoparticles with a size of less than 10 nm. Previous research has shown that C-dot synthesized from palm kernel meal using hydrothermal methods has the highest emission intensity among other palm oil wastes. This study aims to determine the optimal conditions for synthesizing C-dot from palm kernel meal hydrothermally with variations in the synthesis temperature, synthesis time, and concentration through variations in solvent volume. The highest C-dot yield of 9,30% was achieved at 200 °C for 24 hours with 80 mL solvent. The optimum condition based on the C-dot emission intensity was reached at 200 °C for 8 hours with 40 mL solvent. The UV-Vis spectrophotometer analysis showed a shift in the peak absorption wavelength. There was an increase in the emission intensity of C-dot synthesized from 150 °C to 200 °C. However, the emission intensity decreased at 250 °C. The FTIR spectrum indicates the presence of function groups commonly found in C-dot, such as O-H and C=O. Analysis using PSA shows large particle sizes and a distribution of particle sizes with low homogeneity.
Keyword: fluorescence, C-dot, emission, hydrothermal, palm kernel meal

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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