Judul: Model Prediktif Pertumbuhan Staphylococcus aureus pada Rendang Daging Sapi
Abstrak: Model mikrobiologi prediktif merupakan model matematika yang digunakan untuk mengetahui pertumbuhan mikroorganisme serta responnya terhadap kondisi lingkungan sehingga dapat diketahui populasinya. Rendang merupakan salah satu makanan tradisional khas Sumatera Barat. Makanan ini terbuat dari daging sapi yang dimasak selama 4 hingga 5 jam bersama dengan santan, bawang putih, bawang merah, dan rempah-rempah lainnya. Proses pemasakan rendang serta tambahan rempah-rempah seharusnya dapat meminimalisir cemaran bakteri pada rendang, namun masih ada korban keracunan akibat rendang. Tujuan dari penelitian ini adalah untuk menentukan parameter kinetik pertumbuhan S. aureus pada rendang daging dengan menggunakan model prediktif pada berbagai suhu penyimpanan, dan menyusun kurva pertumbuhan S. aureus pada rendang daging. Suhu penyimpanan yang digunakan adalah 26, dan 35°C. Model primer yang digunakan adalah model Huang, Baranyi dengan h0, Baranyi bebas h0, dan modifikasi Gompertz sedangkan model sekunder yang digunakan yaitu model Ratkowsky. Hasil penelitian menunjukkan bahwa suhu penyimpanan rendang daging sapi terbaik yaitu pada suhu ruang (26°C) karena tidak ditemukan pertumbuhan pada suhu rendah. Berdasarkan hasil penelitian, dapat disimpulkan bahwa model modifikasi Gompertz memiliki hasil fitting kurva terbaik.
Keyword: Kurva pertumbuhan, Model prediktif, Rendang daging sapi, growth curve, modified Gompertz model, predictive model, rendang beef

Judul: Pendugaan Pertumbuhan Staphylococcus aureus pada Sosis Ayam Dengan Penyimpanan Dingin Menggunakan Response Surface Methodology
Abstrak: This research studied the effect of low temperature (-5, 2.5, and 10 °C) and the initial member of S. aureus (0 to 100 cfu gram-1) on the growth curve of S. aureus in chicken sausage, in order to determine the growth rate and lag phase model of S. aureus. The data were plotted and fitted using Response Surface Methodology (RSM) to obtain the growth models of the bacteria under defined conditions. Steps of the study included sample preparation (preparation and confirmation of inoculum following by inoculation of S. aureus cultures on chicken sausage samples), determining the growth pattern of S. aureus ATCC 25923 in chicken sausage at storage temperature 35-37 ºC and 25-30 ºC for 24 hours, as well as at -5 to 10 ºC for 1 to 2 week. The data were then proced using RSM to obtain modelling, model validation, and growth curves plotting based on the Baranyi equation. Growth rate of S. aureus (cfu gram-1 day-1) with concentration factor 0, 20, dan 100 cfu gram-1 and storage temperature -5 until 10 °C in BPA + egg yolk tellurite is y = 0.0093 + 0.0158 temperature + 0.0011 concentration + 0.0003 temperature *concentration. R2 0.60 with confident level 95%. Lag time of S. aureus (day) with concentration factor 0, 20, dan 100 cfu gram-1 and storage temperature -5 until 10 °C in BPA + egg yolk tellurite is y = 0.1680 + 0.0193 temperature + 0.2857 concentration + 0.0052 temperature*concentration. R2: 0.58 with confident level 95%.
Keyword: 

Judul: Hybrid solar cells of ZnO nanoparticles/chlorophyll was modified metal ions (Zn2+ and Cu2+ )
Abstrak: Zinc Oxide (ZnO) is a n-type semiconductor with a wide the energy band (Band Gap) is 3.37 eV at room temperature and 3.34 eV at low temperature with a large exiton binding energy is 60 meV. ZnO has been synthesized by hydrothermal method, resulting in a decrease in particle size over the duration of the hydrothermal changes. Crystallographic structure of ZnO were characterized using XRD, has shown the characteristic pattern of a hexagonal wurtzite structure, the crystallite size increases to changes in particle size. Changes in particle size has also led to a change in the absorption peak of ZnO as has been demonstrated posted under test using the optical properties of UV-Vis spectrophotometer. Changes of this uptake has also led to changes in the energy band gap, which increases its band gap energy of the particle size. In electronic applications, especially in solar cells. Chlorophyll is considered less effective, because of their very nature are easily degraded as a result of several reactions which are acid, lighting and temperature. The results of the stability test using a halogen lamp 34 W/m2 for 5 hours, that the substitution of chlorophyll with metal ions Zn2+ and Cu2+ has been shown to form more stable than natural chlorophyll. The characterization of the optical properties, the combination of ZnO / chlorophyll in the form of hybrid films has led to a shift in the absorption region of ZnO becomes more widely from the UV to Visible. ZnO/chlorophyll has absorption range of 350-515 nm, ZnO / Zn-feofitin 332-401 nm and 332-632 nm for Cu-feofitin. The combination of ZnO/chlorophyll and CuSCN as a solid electrolite in hybrid solar cell, a modified chlorophyll with metal ions Zn2+ and Cu2+ has been shown to form a more stable I-V curve. It is characterized by its fill factor value greater than natural chlorophyll. Nevertheless, solar cells with natural chlorophyll has been able to produce higher efficiency values of chlorophyll were substituted.
Keyword: Hydrothermal, ZnO/Chlorophyll modified, Hybrid Solar Cell