Judul: Pengukuran acoustic backscattering strength dasar perairan Teluk Jakarta menggunakan multibeam echosounder
Abstrak: MBES (Multibeam Echosounder) memiliki kemampuan dalam melakukan pemindaian dasar laut dengan akurasi tinggi dan cakupan yang luas. Teluk Jakarta merupakan kawasan perairan yang sangat strategis dari segi ekologis maupun ekonomis. Perairan ini menerima masukan sedimen yang tinggi dari daratan yang disebabkan oleh tingginya curah hujan dan banyaknya aliran sungai, hal ini menyebabkan perubahan kawasan perairan Teluk Jakarta relatif cepat terkait dengan perubahan substrat dasar perairan. Penelitian ini bertujuan untuk mengetahui nilai hambur balik di dasar perairan Teluk Jakarta dengan menggunakan instrumen multibeam echosounder dan menghubungkan nilai hambur balik dengan tipe sedimen. Penelitian ini megambil data sampel sedimen pada 5 stasiun untuk melakukan validasi data nilai hambur balik akustik dengan jenis sedimennya. Pengolahan data multibeam echosounder dilakukan menggunakan software MB-System yang berbasis sistem operasi linux 16.04. Analisis sampel sedimen dilakukan menggunakan segitiga shepard dengan membagi sedimen menjadi 10 fraksi kemudian dianalisis menjadi 3 kategori yakni pasir, lumpur dan liat. Hasil analisis sedimen pada 5 stasiun Teluk Jakarta terlihat bahwa jenis sedimen dminan merupakan pasir berlumpur. Nilai hambur balik akustik dan substrat berkisar antara -21.6 dB hingga -30.2 dB dengan kedalaman yang bervariasi antara 3.32 – 17.33 meter dan semakin dangkal apabila mendekati pulau. Nilai hambur balik setiap substrat berbeda karena dipengaruhi oleh komposisi pasir, lumpur dan liat pada dasar perairan. Semakin tinggi komposisi pasir pada substrat tersebut maka semakin tinggi nilai hambur baliknya.
Keyword: Multibeam Echosounder, MB-System, Teluk Jakarta, nilai hambur balik, substrat

Judul: Pengukuran Hambur Balik Akustik Dasar Laut di Sekitar Kepulauan Seribu Menggunakan Split Beam Echosounder.
Abstrak: The purpose of this research is to compute the backscattering strength of the seabed by measuring volume backscattering strength (SV), bottom surface backscattering strength (SS), and the echo level (EL) from seabed using split beam echosounder. The research was conducted from 29th January to 3rd February 2011, around the Seribu Islands: Pramuka island, Panggang island, Karya island and Semak Daun island, North Jakarta. Acquisition of acoustic data was conducted using the SIMRAD EY 60 instrument. Acoustic data obtained from 9 stations simultaneously with sediment sampling. Acoustic processing data was conducted by Rick Towler program with Matlab based. The SV and SS were analyzed Manik et al, model by using. Sediment sampling station consisted of 9 stations: Pramuka island there are 1 station (Station 1), Karya island there are 2 stations (Station 2, and Station 3), Panggang island there are 3 stations (Station 4, Station 7, Station 9), and Semak Daun island there are 3 stations (Station 5, Station 6, Station 8). Sediment classified based on the sediment texture. Seabed surface sediments were separated into 3 types, they are: sand, mud, and clay. This analysis showed that the location of the 9 stations observation is dominated by sand fraction with the percentage of 80.85%. Mud and clay fractions had the average percentage value of 18.32% and 0.83%, respectively. The backscattering value (SV) of sand substrate ranged -10.62 to -18.51 dB with the average of -13.91 dB, and the muddy sand substrate ranged from -16.58 to -25.42 dB with the average -20.57 dB. The value of SS for the sand substrate ranged from -20.70 to -28.58 dB with the average value of -23.98 dB. Muddy sand substrate has a value of SS in the range of -26.64 to -35.49 dB with the average SS of -30.64 dB, from this research, the classification of seabed type using hydroacoustic technology was possible.
Keyword: 

Judul: Prenilasi Senyawa β-Diketon sebagai Prekursor 3-Prenilflavon
Abstrak: One group of flavonoids that has not been commonly synthesized is 3- prenylflavone. The main objective of this experiment was to synthesize precursor of 3-prenylflavone. Firstly, β-diketone was synthesized via 4 steps from phenol as starting compound with total yield of 24%. Prenylation of β-diketone with prenyl bromide and K2CO3 base produced 4 fractions which were separated by using preparative thin layer chromatography (PTLC) with n-hexane:EtOAc (8:2) as the eluent. Fraction with Rf = 0.80 was further separated by using preparative PTLC with n-hexane:EtOAc (99:1) as the eluent. Two fractions were obtained with Rf = 0.38 and 0.42. The first fraction has been characterized as diprenylated β-diketone with 49% yield. Application of protecting group on the phenolic OH group in β- diketone are needed to obtain monoprenylated β-diketone which can be further cyclized into 3-prenylflavone
Keyword: