Judul: Rekayasa Teknologi Pemanenan Mikroalga melalui Perbedaan Densitas Flokulan pada Teknik Bio-flokulasi.
Abstrak: Harvesting method is one crucial process during microalgal cultivation for development of bioenergy, thus low-cost bio-flocculation technique needs continuous improvement for yielding higher biomass and faster harvesting period. The study was conducted by mixing Tetraselmis suecica (flocculant) with microalgal species of Chlorella sp. and Nannochloropsis sp. (non-flocculants) to determine the rate of deposition from several treatment (P1-P4). The results showed that Tetraselmis suecica was functional in accelerating harvest of Chlorella sp. and Nannochloropsis sp, with the highest precipitation observed at P4. The deposition rate of Chlorella sp. was increased from 52.12±1.91% to 70.44±0.22%, while Nannochloropsis sp. from 13.84±1.27% to 45.06±0.75% after Tetraselmis suecica was added. Rate of deposition during bio-flocculation process was proven efficient at indoor scale cultivation compare to outdoor. Lipid yielded from bio-flocculation technique was higher compare chemical flocculant, such as NaOH.
Keyword: bio-flocculation, Chlorella sp., harvesting, Nannochloropsis sp., Tetraselmis suecica

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: 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