Judul: Deteksi Nilai Hambur Balik Karang Massive Menggunakan Insrumen Hidroakustik CruzPro Fish Finder PcFF-80
Abstrak: In Indonesia hydroacoustic methods have been used in various marine research. Using Hydroacoustic method is one of many alternatives have been developed to get information about coral reef. This research describes an attempt to analysis back scattering value of massive coral using hydroacoustic instrument. Data collection was carried out in Karang Beras Island, DKI Jakarta province by CruzPro instrument which operated with frequency 200 kHz. Data validation of coral reef was performed by visual observation which documented using underwater camera. Back scattering strength value is gotten from first echo (E1) and second echo (E2). The result is showed that the average value of volume back scattering strength from first echo (E1) has range -19.11 dB to -18.00 dB and second echo (E2) has range -45.51 dB dB to -41.97 dB. The average value of surface back scattering strength from first echo (E1) has range -15.56 dB to -14.45 dB and second echo (E2) has range -41.96 dB dB to -38.42 dB.
Keyword: second echo, massive coral, first echo, CruzPro, back scattering

Judul: Aplikasi Single Beam Echosounder Simrad EK15 untuk Pengukuran Hambur Balik Akustik Koloni Karang
Abstrak: Indonesia dan beberapa negara berkembang lainnya masih memanfaatkan teknologi hidroakustik dengan transduser single beam dibandingkan dengan teknologi beam lebih dari satu karena harganya yang relatif lebih murah. Perlu adanya basis data nilai hambur balik akustik objek dasar perairan untuk memudahkan dalam survei pendugaan dasar perairan menggunakan metode hidroakustik. Tujuan penelitian ini adalah membandingkan dan mengelompokkan nilai area backscattering coefficient dan area backscattering strength pada tipe pertumbuhan koloni karang dan jenis substrat dasar perairan dengan menggunakan instrumen single beam echosounder Simrad EK15. Data akustik ditampilkan dalam bentuk echogram dan dikonversi menjadi nilai digital berupa area backscattering coefficient dan area backscattering strength dari hambur balik echo pertama (E1) dan hambur balik echo kedua setelah dihamburkan kembali dari permukaan (E2) yang merepresentasikan kekasaran dan kekerasan objek yang terdeteksi. Ground check dengan penyelaman SCUBA dilakukan untuk memastikan instrumen yang digunakan tepat mendeteksi objek dasar perairan yang diinginkaan. Uji statistik dilakukan untuk membuktikan bahwa nilai E1 maupun E2 dapat dibedakan dan dikelompokan berdasarkan sifat kemiripan dan ketakmiripan dari objek dasar perairan yang terdeteksi. Nilai E1didapatkan berkisar antara -32.42 hingga -24.48 dan nilai E2 didapatkan berkisar antara -51.35 hingga -38.02 Urutan nilai E1 maupun E2 dari yang tertinggi berturut-turut yaitu coral massive, acropora tabulate, coral foliose, acropora branching, pecahan karang/rubble, dan substrat pasir. Semua parameter yang diujikan memiliki nilai yang berbeda nyata dengan nilai kepercayaan 95%. Berdasarkan nilai E1 dan E2 dengan analisis multivariat, didapatkan dua kelompok utama yang memiliki tingkat kemiripan yang tinggi yaitu kelompok coral massive dan acropora tabulate serta kelompok acropora branching, pecahan karang/rubble, dan substrat pasir.
Keyword: hidroakustik, karang, parairan

Judul: Characterization of The Chemical Constituents and Antioxidant Capacity of Green and Oolong Teas (Camellia sinensis) Manufactured in Thailand
Abstrak: Tea in Thailand most manufactured in northern area, especially Chiang Rai, Chiang Mai, Nan, and Mai Hang Son province. The aim of this study was to determine and compare the chemical compositions and antioxidant capacity of 4 important Thai tea products. A total of 13 of green teas of 2 major cultivars, assamicaand cv. oolong no.12 (chin hsuan oolong) and 26 of oolong tea of 2 major varieties, cv. oolong no. 12 and cv. oolong no. 17 (chin shin oolong) were collected from 18 factories in Chiang Rai province in 2011. The total polyphenol content was determined according to International Organization for Standardization (ISO 14502-1). For antioxidant capacity, DPPH radical scavenging activitiy assay and ferric reducing antioxidant power assay were determined. The catechins content and caffeine content were determined using HPLC by ISO method (ISO-14502-2). Results showed that about 95% of the 39 tea samples manufactured in Thailand had moisture content below 7%, 5% of tea samples being above 7%. The total polyphenol content in green tea was found to vary from 11.86 to 21.19%GAE, while in oolong tea was found in a range of10.22 to 17.57%GAE. The caffeine content in green tea samples were in a range of 1.69 to 3.7%, while in oolong tea samples were in a range of 1.61 to 3.26%. The catechin content in green tea samples were in a range of 8.31-14.08%, while in oolong tea samples were in a range of 6.81-12.46%. The antioxidant capacity in green tea samples was 164.01 mmole TE/100 g dry basis, while in oolong tea samples was about 132.73mmole TE/100 g dry basis. This study provided useful information for the tea industry in Thailand and other countries in processing and selecting a good-quality tea.
Keyword: Antioxidant capacity, Camellia sinensis, Green tea, Oolong tea, Thailand