Judul: Model Matematika Penyebaran Penyakit Demam Berdarah Dengue
Abstrak: Dengue disease was transmitted to human through infected mosquito Aedes Aegypti. It was found widely in the tropical regions of the world. Infection of dengue virus could be grouped into two mechanisms. The first mechanism was vertical transmission in mosquito body, where virus could be transmitted by female mosquito into her eggs. The second mechanism was transmission from mosquito into human body and conversely. In this study, mathematical models were used to study the behavior of the transmission of dengue disease. The mathematical model of the disease with assumption of healthy mosquito eggs was compared to the modified mathematical model of dengue disease assuming that some of mosquito eggs were infected by dengue virus. The seasonal influence, especially temperature, was considered in the analysis. The standard dynamical analysis was applied to both mathematical models. Numerical results showed that infected mosquito eggs influenced the spreading of dengue disease. There were bigger oscillation in the susceptible and infected human population, as well as in the infected mosquito, as a result of stronger seasonal influence during extrinsic incubation.
Keyword: Dengue disease, Mathematical model, Etrinsic incubation period, DBD, Sistem persamaan diferensial, Titik tetap, Pelinieran, Multi spesies, Kriteria Routh-Hurwitz, Solusi numerik sistem persamaan diferensial, Analisis kestabilan, Simulasi model

Judul: Analisis Model Asimtomatik Penyebaran Penyakit Demam Berdarah Dengue
Abstrak: Demam Berdarah Dengue adalah penyakit yang disebabkan oleh gigitan nyamuk Aedes aegypti dan Aedes albopictus . Penyakit ini memiliki empat jenis virus yaitu DEN-1, DEN-2, DEN-3, dan DEN-4. Individu yang terinfeksi memiliki gejala yang berbeda-beda bahkan ada yang tidak menunjukkan gejala atau asimtomatik. Karya ilmiah ini membahas model penyebaran penyakit dengan adanya pengaruh asimtomatik pada suatu populasi manusia yang tertutup. Berdasarkan analisis terdapat dua titik tetap yaitu titik tetap bebas penyakit dan titik tetap endemik. Untuk menentukan nilai parameter yang mempengaruhi penanggulangan penyebaran penyakit DBD, dilakukan analisis sensitivitas dan simulasi numerik. dst..., engue Fever is a disease caused by the bite of the Aedes aegypti and Aedes albopictus mosquito. This disease has four types of viruses namely DEN-1, DEN-2, DEN-3, and DEN-4. Infected individuals have different symptoms and some even show no symptoms or asymptomatic. This scientific work discusses the model of the spread of disease with an asymptomatic influence on a closed human population. Based on the analysis there are two fixed points, namely the fixed point free of disease and the endemic fixed point. To determine the value of parameters that affect the prevention of the spread of dengue disease, sensitivity analysis and numerical simulations are carried out. etc ...
Keyword: SIR type, dengue fever, basic reproduction number, sensitivity analysis

Judul: Katalis Eterifikasi Gliserol Berbasis Poli–(asam stirena sulfonat) dari Limbah Styrofoam.
Abstrak: Styrofoam waste can be converted to poly–(sulfonate styrene acid) (PSSA) that can be used as catalyst. The objective of this research is to get PSSA that can catalyze the etherification of glycerol and benzyl alcohol. The styrofoam waste was converted to PSSA by reacting with H2SO4 98% (as sulfonation agent) and P2O5 (as sulfonation catalyst) at 40 °C for 6 hours. Characterizations of PSSA included functional groups, sulfonation levels, water swelling, and thermal stability. The yield of PSSA was 40-55%. The success of sulfonated polystyrene was shown by –SO3H group absorption at 1157.29 cm-1. Etherification of glycerol and benzyl alcohol using PSSA catalyst was conducted at 110 °C for 12 hours. The conversion in producing mono–benzyl ether glycerol was 8.10%, 1,3–dibenzyletherglycerol 2.60%, and dibenzyl ether 9.80%. Therefore, the PSSA can be used as etherification catalyst.
Keyword: benzyl alcohol, etherification, glycerol, polystyrene, PSSA