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: Stochastic Spatial Model Of The Spread Of Dengue Hemorrhagic Fever.
Abstrak: Demam berdarah dengue (DBD) merupakan jenis penyakit menular yang disebabkan oleh organisme pathogen dan dapat menular yang dikenal dengan virus dengue. Virus dengue disebarkan oleh nyamuk Aedes aegypti, di mana jenis nyamuk ini dapat berkembang biak di kawasan pemukiman manusia dan dapat bertahan hidup di dalam ruangan. Nyamuk yang sudah terinfeksi virus dengue dapat menularkan virus pada tubuh manusia jika nyamuk tersebut menggigit manusia yang rentan. Penularan virus pada tubuh manusia dapat menyebabkan manusia tersebut mengidap penyakit demam berdarah dengue. Gejala penyakit demam berdarah dengue diantaranya yaitu sakit kepala, nyeri sendi dan tulang, ruam kemerahan pada kulit, sakit pinggang dan sakit perut yang disertai muntah. Prasetyowati dan Seran (2012) menjelaskan bahwa virus dengue memiliki kemampuan untuk bertransmisi secara transovarial yaitu transmisi dari induk ke telur nyamuk. Oleh sebab itu penulis tertarik untuk membuat suatu penelitian yang memodifikasi model dari Otero dan Solari (2009) dengan menambahkan asumsi transovarial di atas. Pada penelitian ini digunakan model stokastik untuk menggambarkan dan menganalisis beberapa faktor yang dapat menjadi penyebab terjadinya penyebaran virus dengue. Model stokastik cocok untuk diterapkan karena model ini memuat cakupan yang memadai untuk menganalisis kejadian yang mengandung peubah acak. Dalam hal ini peubah acak tersebut direpresentasikan oleh gambaran peristiwa pada sistem. Tujuan dari penelitian ini adalah: melakukan modifikasi model Otero dan Solari, merumuskan dan menghitung peluang terjadinya wabah secara analitik dan melihat perubahan nilai peluang wabah terhadap variasi suhu dan kepadatan breeding sites pada suatu lingkungan, melakukan simulasi numerik pada model modifikasi untuk melihat dinamika subpopulasi manusia terekspos dan terinfeksi berdasarkan pengaruh variasi suhu dan kepadatan breeding sites nyamuk Aedes aegypti pada suatu lingkungan., Dengue hemorrhagic fever is an infectious disease caused by pathogenic and infectious virus known as dengue virus. The dengue virus is spreaded by Aedes aegypti mosquitoes, that can breed well in human settlements and they often live indoors. The infected mosquito can transmit virus in human body through its bites. Transmission of the virus in the human body can cause dengue hemorrhagic fever. Symptoms dengue fever disease are headache, joint and bone pain, redness of the skin rash, back pain and abdominal pain accompanied by nausea and vomiting. Prasetyowati and Seran (2012) explained that dengue virus has ability to transmit vertically i.e. dengue virus transmits from mosquito to mosquito eggs. In this work, the Otero and Solari’s model (2009), will be modified with additional assumption of vertical transmission as described above. In this research, a stochastic model is used to describe and analyze some factors causing the spread of dengue virus. The stochastic model is suitable for this model because it contains random variables. In this case the random variables represented by number of individuals in the system. The purpose of this research were: to modify the Otero and Solari models, formulate and calculate the probability of outbreaks analitically. The computer simulation was conducted to study the effect of environmental temperature and breeding sites on the level of exposed and infected humans.
Keyword: breeding site, dengue virus, spatial, stochastic model, temperature, Dengue virus, Infectious virus, Solari models

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