Judul: Analisis Sensitivitas Model Penyakit Coronavirus (COVID-19) Terhadap Tindakan Intervensi
Abstrak: Pada akhir tahun 2019, dunia dikejutkan dengan adanya wabah penyakit baru yaitu Covid-19. Pandemi Covid-19 ini, telah memberikan dampak terhadap berbagai sektor. Berbagai tindakan intervensi telah dilakukan, namun belum diketahui secara pasti tingkat keefektifan dari tindakan-tindakan tersebut dalam pencegahan penyebaran penyakit Covid-19 ini. Oleh karena itu penelitian ini bertujuan untuk menganalisis sensitivitas parameter intervensi pada model penyebaran penyakit coronavirus (Covid-19). Analisis ini dilakukan dengan menentukan nilai indeks sensitivitas masing-masing parameter terhadap bilangan reproduksi dasarnya (ℛ0) . Dalam penelitian ini ℛ0 ditentukan dengan menggunakan matrix next generation. Hasil analisis sensitivitas menunjukkan bahwa mengurangi tingkat kontak antar individu dan menerapkan pola hidup sehat sehingga sistem imun meningkat, hal tersebut cukup efektif untuk mencegah penyebaran coronavirus berdasarkan model dan analisis ini., In the end of 2019, the world was shocked by the outbreak of Covid-19 disease. Various interventions have been carried out, however it is not certain the level of effectiveness of these measures in preventing the spread of the Covid-19 disease. Therefore, this study aimed to analyze the sensitivity of the intervention parameters in the model. This analysis was carried out by determining the sensitivity index value of each parameter on the basic reproduction number (ℛ0). The ℛ0 itself, was calculated using the next generation matrix method. The results of the sensitivity analysis show that reducing the level of individuals contact and implementing healthy lifestyle were found to be effective in preventing the spread of Covid-19 disease.
Keyword: analisis sensitivitas, bilangan reproduksi dasar, matriks next generation, penyakit Covid-19

Judul: Mathematical Model of the Impact of Face Mask Use and Social Distancing on the Spread of COVID-19
Abstrak: Coronavirus Disease 2019 atau lebih dikenal dengan nama COVID-19 adalah penyakit menular yang menyerang sistem pernapasan manusia. Penelitian ini bertujuan menganalisis pengaruh penggunaan masker dan penerapan social distancing, serta parameter lain terhadap penyebaran penyakit COVID-19. Langkah yang dilakukan dalam penelitian ini adalah dengan mencari kestabilan titik tetap dan bilangan reproduksi dasar model, melakukan analisis sensitivitas, serta melakukan simulasi numerik. Hasil analisis sensitivitas dan simulasi numerik menyatakan bahwa untuk mencapai kondisi bebas penyakit diperlukan tindakan mengurangi laju transmisi efektif penyebaran COVID-19, meningkatkan laju pemulihan individu yang terinfeksi COVID-19 dengan gejala serta meningkatkan proporsi individu yang melakukan social distancing dan menggunakan masker wajah secara efektif., Coronavirus Disease 2019 or more known as COVID-19 is an infectious disease that attack the human respiratory system. The purpose of this study was to analyze the effect of face mask use and the application of social distancing and also other parameters on the spread of COVID-19 disease. The steps taken in this study are to determine the fixed point and basic reproduction number of the model, to carry out sensitivity analysis and numerical simulation. The results of sensitivity analysis and numerical simulations showed that in order to achieve disease-free conditions, it is necessary to reduce the effective transmission rate of the spread of COVID-19, to increase the recovery rate of humans infected with COVID-19 with symptoms, and to increase the proportion of humans who apply social distancing and use face masks effectively.
Keyword: Sensitivity analysis, Basic reproduction number, Coronavirus

Judul: Separation of Neodymium from U3Si2/Al Fuel Plate for Burn-Up Determination
Abstrak: Neodymium is a common fission product produced in nuclear fission reactions. Neodymium in this study was chosen as a burn-up indicator for U3Si2/Al fuel element plates because the neodymium isotope is a stable fission product with a fairly high yield. Some procedures were carried out to separate neodymium, starting with the separation of cesium isotopes (137Cs, 134Cs) through the precipitation method, then separation of uranium isotopes (235U, 238U) and plutonium isotopes (239Pu, 238Pu) with Dowex 1x8 ion exchange resin, and separation of neodymium (Nd), samarium (Sm), as well as cerium (Ce) with Dowex 1x4 ion exchange resin. The Cs recovery reached 99.95%. The U and Pu isotopes resulting from the separation are subjected to an electrodeposition process and the weight of each isotope can be measured with an alpha spectrometer. The separation results of Nd from Sm and Ce have been proven using an XRF spectrometer. The neodymium isotopes separation was corrected using the standard addition method, and an average total Nd content of 2.4 ppm was obtained in the PEB U3Si2/Al bottom solution. It is hoped that this separation method can be applied in determining burn-up of nuclear fuel.
Keyword: neodymium, burn-up indicator, U3Si2/Al fuel plate