Judul: Model Turunan Terbatas untuk Pendugaan Laju Pembekuan Daging Sapi
Abstrak: Skripsi ini disusun berdasarkan penelitian yang dilakukan di PT Abattoir Surya Jaya, Surabaya. Penelitian dilaksanakan pada tanggal 15 September sanpai 1 Oktober 1987. Tujuan penelitian ini adalah: 1) nenyusun program komputer model turunan terbatas untuk menduga laju penbekuan daging sapi dengan menggunakan "air-blast freezern dan 2) menguji ketepata-n model pendugaan terhadap hasil pengukuran.
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Judul: Model pendugaan laju pembekuan daging kambing dengan metode beda hingga
Abstrak: Skripsi ini merupakan hasil penelitian yang dilakukan di Bangsal Percontohan Pengolahan Hasil Pertanian dan di Laboratorium Teknik Pengolahan Pangan dan Hasil Pertanian, Jurusan Mekanisasi Pertanian, Institut Pertanian Bogor. Penelitian ini mempunyai tujuan :1) menentukan per- kembangan sifat-sifat termofisik daging kambing selama pembekuan, dan 2) menyusun model simulasi komputer untuk menduga laju pembekuan daging kambing dalam bentuk lempengan datar tak terhingga dengan metoda beda hingga. Pengukuran laju pembekuan daging kambing dilakukan dengan menggunakan alat pembeku "air blast freezer". Daging kambing yang diukur penurunan suhunya tersebut dibuat berbentuk balok dengan ukuran 100 x 100 mm dan dengan tiga macam ketebalan, yaitu 1 cm, 2 cm dan 3 cm. Suhu ruangan pada "air blast freezer" sebesar -27.2 °C. Model numerik yang digunakan adalah model numerik skema Crank Nicholson. Perhitungan model numerik dilaku- kan pada setiap interval waktu (At) dengan menggunakan jumlah interval jarak (Ax) yang berbeda-beda untuk tiap ketebalan sedemikian hingga mempunyai jarak yang sama...
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Judul: Bioelectricity Production from Citrobacter freundii GBH253 and Chlorella pyrenoidosa on Microbial Fuel Cell Anode with Different Carbon Sources
Abstrak: Microbial Fuel Cell (MFC) development has significantly increased from various aspects to get higher and more stable electricity. Developing MFC on microorganism aspect is very important because it plays a crucial role in the MFC system. C. freundii GBH253 is one of the potential exoelectrogen bacterium that could be developed for the MFC system. Integrating C. freundii GBH253 and electricity-producing microalgae, such as C. pyrenoidosa, in the anode of MFC could get more stable and higher electricity. In this study, C. freundii GBH253 and C. pyrenoidosa were coupled to produce electricity from different substrates. C. freundii GBH253 and C. pyrenoidosa were tested on three different media types before being tested on MFC. They were also examined for the co-cultivation test to determine the symbiotic relationship between the two microorganisms. The MFC test was conducted using the Randomized Block Design Factorial and the Tukey test to see significant differences from each treatment. The parameters observed in this study were voltage, power density, Chemical Oxygen Demand (COD), Coulombic Efficiency (CE), pH, and volatile fatty acid (VFA). C. freundii GBH253 cannot grow on microalgae medium, while C. pyrenoidosa could grow on bacterial medium and a mixture of bacterium and microalgae media. The bacterium gained benefit from co-culture with microalgae. In the MFC test, electricity was generated in all treatments, which bacterium + microalgae with acetate treatment could generate power density up to 211,97 mW/m2 and the most stable compared to others. Production of electricity in bacterium-microalgae combination dominated by the bacterium; hence, microalgae still help bacterium by producing electricity and raised the COD value. The pH value of all treatments was higher than the initial pH. Acetate and phenol were VFA produced in all treatments, whereas butyric acid and propionic acid were found in some treatments. Pearson correlation showed that some VFA highly correlated with power density.
Keyword: Chlorella pyrenoidosa, Substrate, Microbial Fuel Cell, Electricity Producing Microalgae, Volatile Fatty Acid, Citrobacter freundii