Judul: Analisis Pengaruh Lockdown terhadap Infeksi Ulang dalam Dinamika Penyebaran Covid-19
Abstrak: Coronavirus Disease 2019 (Covid-19) ditularkan dari manusia ke manusia melalui kontak langsung, permukaan, atau menghirup tetesan pernapasan. Covid-19 ditetapkan sebagai pandemi karena penyebaran infeksi baru yang terus meningkat. Pada penelitian ini, model penyebaran Covid-19 pada penelitian Bugalia et al. (2020) dimodifikasi dengan menambahkan kasus infeksi infeksi ulang. Modifikasi ini bertujuan untuk mengetahui pengaruh penerapan lockdown terhadap penyebaran Covid-19 pada suatu populasi. dst ,,,
Keyword: Covid-19, Infeksi Ulang, Lockdown

Judul: Kajian Efek Lockdown dalam Penyebaran Penyakit Menular Covid-19: Analisa Model Matematika SIQ
Abstrak: COVID-19 dapat menyebar dengan cepat melalui kontak langsung dengan penderita COVID-19. Perpindahan penduduk dari wilayah yang telah banyak memiliki kasus COVID-19pun menjadi salah satu penyebab penyakit ini menyebar begitu cepat, maka pembatasan suatu wilayah atau yang biasa disebut dengan lockdown diperlukan untuk dapat menanggulangi penyebaran COVID-19 ini. Model SIQ digunakan untuk mempelajari penyebaran COVID-19. Diperoleh dua titik tetap ketika lockdown diterapkan, yaitu titik tetap bebas penyakit dan titik tetap endemik. Saat titik tetap bebas penyakit, maka penyakit dapat punah. Sedangkan saat titik tetap endemik, berdasarkan simulasi numerik penerapan lockdown berpengaruh untuk menekan peningkatan populasi individu terinfeksi. Pertumbuhan populasi individu terinfeksi saat lockdown juga sangat kecil jika dibandingkan dengan tanpa pemberlakuan lockdown., COVID-19 can spread quickly through direct contact with people with COVID-19. The movement of the people from the areas that already have a lot of COVID-19 cases is also one of the causes of this disease spreading so fast, so the restriction of an area or commonly called a lockdown is needed to be able to cope with the spread of COVID-19. The SIQ model is used to study the spread of COVID-19. Two fixed points are obtained when the lockdown has been implemented, namely the disease-free fixed point and the endemic fixed point. In the disease-free fixed point, the disease can become extinct. Meanwhile, in the endemic fixed point, based on numerical simulations, the implementation of the lockdown is intended to result lower of the level of infected individuals. In fact, the growth of the population of infected individuals when the lockdown is applied is very small, compared to simulation of no lockdown applied.
Keyword: COVID-19, lockdown, mathematical model, SIQ

Judul: Pembuatan Film Tipis Cu2ZnSnS4 sebagai Lapisan Penyerap Cahaya pada Sel Surya Menggunakan Metode Elektrodeposisi
Abstrak: Thin film of Cu2ZnSnS4 (CZTS) is an alternative semiconductor used as light absorber layer on solar cell. CZTS can replace silicon that commonly used as commercial semiconductor. The advantage of using CZTS as absorber layer is due to the abundance of its chemical composer on earth, and its high value of absorption coefficient. The absorber layer was made by using electrodeposition method on ITO glass substrates. The films were deposited at room temperature using potentiostatic mode with a potential of –1.05 V for 30, 45, and 60 minutes. After that, the films were annealed at two different temperatures, 180 ºC and 500 °C, for 45 minutes in N2/H2S atmosphere. Based on X-ray diffraction analysis, the polycrystalline thin film obtained fall into kesterite crystal phase. This type of crystal was obtained when the CZTS was annealed at 500 °C in H2S/N2 atmosphere. The value of optical band gap energy for the CZTS thin film was 2.2 eV with the film thickness about 1.228–6.366 μm. The sample of CZTS with electrodeposition time of 45 minutes and annealing temperature of 500 °C showed the best result and in conformity with absorber layers criteria for solar cells.
Keyword: semiconductor, ITO glass, CZTS thin film, electrodeposition