Judul: Pengembangan Bio-flokulasi sebagai Teknik Pemanenan Mikroalga Ramah Lingkungan
Abstrak: Microalgae harvesting is an important part in microalgae cultivating system. Microalgae harvesting technique system which commonly used are centrifugation, filtration and flocculation, but those techniques still have some disadvantages, such as not environmentally friendly, and high of energy used and costly. Bio-flocculation harvesting technique using the microalgae as a flocculant agent can be an alternative way to solve those problems. In this research, mixing of Tetraselmis suecica (flocculant) with Chlorella sp., and Nannochloropsis sp. (nonflocculant) in ratio of 1:4, 2:4, 3:4 and 4:4 (v/v) has conducted to obtain % recovery. The results show that Tetraselmis suecica species as a flocculant agent can fasten the harvesting of Chlorella sp. and Nannochloropsis sp. It can be proved with the increase of % recovery value of Chlorella sp. from 51.14±1.07% to 67.34±0.67% and Nannochloropis sp. from 20.52±1.17% to 42.43±0.40% at the first hour. The result shows that bioflocculation can be applied as microalgae harvesting technique.Microalgae harvesting is an important part in microalgae cultivating system. Microalgae harvesting technique system which commonly used are centrifugation, filtration and flocculation, but those techniques still have some disadvantages, such as not environmentally friendly, and high of energy used and costly. Bio-flocculation harvesting technique using the microalgae as a flocculant agent can be an alternative way to solve those problems. In this research, mixing of Tetraselmis suecica (flocculant) with Chlorella sp., and Nannochloropsis sp. (nonflocculant) in ratio of 1:4, 2:4, 3:4 and 4:4 (v/v) has conducted to obtain % recovery. The results show that Tetraselmis suecica species as a flocculant agent can fasten the harvesting of Chlorella sp. and Nannochloropsis sp. It can be proved with the increase of % recovery value of Chlorella sp. from 51.14±1.07% to 67.34±0.67% and Nannochloropis sp. from 20.52±1.17% to 42.43±0.40% at the first hour. The result shows that bioflocculation can be applied as microalgae harvesting technique.
Keyword: Harvesting Mikroalgae, Bio-flocculation, Recovery, Tetraselmis suecica, Chlorella sp., Nannochloropsis sp

Judul: Karakterisasi Pertumbuhan Mikroalga dan Penyisihan Nutrien dari Limbah Cair Rumah Pemotongan Hewan dengan Sistem Kultur Semi Kontinu
Abstrak: Organic wastewater with high nutrient content can stimulate uncontrolled microalgae growth. Whereas discipline control led growth can be very profitable. The research was performed to determine the characteristic of growth microalgae nutrient elimination from slaughterhouse wastewater in semi continuous culture system with 75% concentration of slaughterhouse wastewater : 25% consortium of microalgae. In addition, the separation and harvesting of microalgae for the known oil content was also investigated. Cultivation of microalgae has been done at a temperature and pH of the field approach, then temperature and pH dependent on state in the field daily. The light source is obtained directly from the sun. Circulation in a semi continuous culture media which have been made simply by aeration when sampling. Microalgae consortium cell density attained 640 000 cell/ml. During the cultivation for 18 days, the growth of Chlorella sp dominate the culture, that follow by growth of Euglena on day 20 after the death phase of Chlorella sp through. The best growth of Chlorella sp (on day-12) occurred with a concentration of nutrients containing: 1 mg/l for N-organic content, 1 mg/l for NNH3, 4 mg/l for N-NO3 - then total of nitrogen 6 mg/l, orthophosphate content of 10 mg/l, and potassium values of 87.5 mg/l with consortium cell density attained 3 130 000 cell/ml and TSS Filtration 1 930 mg/l. Convertion of biomass from TSS with amount of nitrogen or TKN (on day 2 until 12) is 180 mg TSS/ mg TKN and convertion of biomass from TSS with orthophosphate content in the same time is 4 200 mg TSS/ mg Orthophosphate. Maximum population of microalgae decrease due to lower nutrient content in culture media. Although the consortium of microalgae dominated by Chlorella sp, oil content (3.03%) and oil productivity is 3 000 liter/ha/year still low compared with a previous study, that have been in research by Hsieh and Wu (2009), Widjaja (2009) along with Danusubrata (2010). It was caused by nutrient treatment which have not yet optimum.
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Judul: Kerusakan bantalan rel kereta api di wilaya inspeksi 2 jalan dan bangunan perusahaan jawatan kereta api (pjka),cirebon
Abstrak: Kereta api merupakan salah satu sarana angkutan yang murah, cepat dan aman serta dapat mengangkut barang dalam jumlah besar. Kelancaran operasi sarana angkutan tersebut banyak ditentukan oleh kondisi jalan rel, termasuk kondisi bantalannya. Dalam hal ini bantalan rel kereta api dapat dibuat dari kayu, logam, atau beton. Namun demikian kayu merupakan bahan yang paling banyak digunakan sebagai pembuat bantalan rel kereta api di berbagai negara. Kenyataan menunjukkan bahwa kayu yang digunakan sebagai bantalan rel kereta api sering mengalami berbagai macam kerusakan yang menyebabkan bantalan tidak berfungsi lagi atau menurun fungsinya. Di Indonesia, informasi mengenai jenis dan tingkat kerusakan bantalan kayu masih sangat kurang, pada- hal informasi tersebut sangat penting sebagai dasar pertimbangan dalam rangka pemeliharaan jalan kereta api, agar umur pakainya (service life) lebih lama.
Keyword: bantalan rel