Judul: Desain model flapping blade vertical axis wind turbine untuk meningkatkan efisiensi konversi energi angin
Abstrak: Angin merupakan salah satu sumber energi terbarukan yang ramah lingkungan. Untuk memaksimalkan pemanfaatan energi angin, desain baru turbin angin pasti dibutuhkan. Penelitian ini bertujuan untuk melihat pengaruh flapping blade pada turbin angin dengan sumbu tegak. Desain turbin yang digunakan pada penelitian ini dimodifikasi dari profil sayap pesawat NACA 6412. Perbedaan jumlah sudu (3, 5, dan 7) digunakan pada penelitian ini. Turbin angin ini diuji dengan menggunakan wind tunnel yang memiki kecepatan angin dengan rentang 0–6 m/s. Performa pada turbin angin tersebut dievaluasi pada beberapa parameter yaitu TSR, torsi, daya angin, daya turbin, dan efisiensi turbin. Hasil yang didapatkan bahwa turbin angin dengan 7 blade memiliki daya turbin yang lebih efisien yaitu 8.532 %.
Keyword: flapping blade, VAWT, the power of wind turbine, efficiency of turbine

Judul: Karakteristik pada Modifikasi Nozzle untuk Wind Lens Turbin Angin Sumbu Horisontal Skala Mikro
Abstrak: Turbin angin mampu mengubah energi kinetik dari angin menjadi energi listrik. Energi angin tidak dapat dikonversi secara keseluruhan karena efisiensi. Efisiensi dapat ditingkatkan dengan menambahkan selubung yang disebut wind lens. Tujuan penelitian ini adalah meningkatkan efisiensi turbin angin yang ditunjukkan dengan power coefficient. Turbin angin yang digunakan pada penelitian adalah Jointiff tipe Wind Pitch WP-1, diameter rotor turbin angin adalah 36 cm, jenis sudu mengacu pada standar NACA 44-series airfoils sebanyak 3 buah. Pengujian dilakukan pada 3 variasi kecepatan angin. Hasil penelitian ini menunjukkan rataan power coefficient turbin angin saja adalah 0.056. Rataan power coefficient turbin angin menggunakan diffuser bersudut brim 90o adalah 0.082. Hasil rataan power coefficient turbin angin yang menggunakan nozzle dan diffuser bersudut brim 90o adalah 0.100.
Keyword: Diffuser, Nozzle, Power coefficient

Judul: Kajian Listeria monocytogenes pada Keju Gouda
Abstrak: Listeria monocytogenes is a foodborne pathogen, which has been associated with several outbreaks of human listeriosis especially in high risk groups. L. monocytogenes could present in Gouda cheeses because it was influenced by various factors, including unsatisfactory pasteurization treatment, contamination after heat treatment, improper sanitizing procedures and ability of this bacteria to forming biofilms. In addition, this bacteria could survive during the process of cheese making and ripening. The purpose of this study were to examine the presence of L. monocytogenes in Gouda cheeses and to provide an overview of Gouda cheese safety of in regards with L. monocytogenes. The samples of this study consisted of 15 local Gouda cheese and 15 imported Gouda cheese which were sold in supermarkets. The samples were taken with considering production code and expired date. The method to detect presence of L. monocytogenes which referred to the Bacteriological Analytical Manual, US Food and Drug Administration and Bergey's Manual of Determinative Bacteriology. The first step was enrichment of samples in Listeria enrichment broth, then isolated in oxford agar and identification step using catalase test, 3% KOH test, Gram stain, carbohydrate fermentation test (mannitol, rhamnose, xylose), motility test and CAMP test. The results of this study showed that L. monocytogenes was not found in 15 samples of local Gouda cheese (0%) and 15 samples of imported Gouda cheese (0%). The absence of L. monocytogenes in local and imported Gouda cheeses was related to combination of preservative factors in Gouda cheese such as pasteurization of milk as raw material for making of Gouda cheese, decrease in pH was caused by the addition of lactic acid bacteria starter cultures, and decline in water activity during the ripening process of Gouda cheeses. The combination of these preservative factors could inhibit the growth of L. monocytogenes could even inactivate L. monocytogenes. In addition, there was not contamination of L. monocytogenes after the pasteurization and during processing of milk to become cheeses. Another factor that could affect the absence of L. monocytogenes in Gouda cheese samples was the number of L. monocytogenes in the samples below the detection limit of conventional method which used in this study. The study could be concluded that all of samples of Gouda cheese were not found the existence of L. monocytogenes and relatively safe from contamination of L. monocytogenes and fulfilled the standard that determined by national standard of Indonesia 7388:2009 about Maximum Limit of Microbial Contamination in Food.
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