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All Journal Jurnal Ilmu dan Teknologi Kelautan Tropis Journal of Engineering and Technological Sciences Jurnal Teknik Sipil BULLETIN OF THE MARINE GEOLOGY JURNAL TEKNIK HIDRAULIK Bulletin of Geology
Totok Suprijo
Faculty of Earth Sciences and Technology, Bandung Institute of Technology
Biochemistry, Genetics & Molecular Biology Civil Engineering, Building, Construction & Architecture Decision Sciences, Operations Research & Management Earth & Planetary Sciences Energy Engineering Library & Information Science

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Modification of Attenuation Rate in Range Normalization of Echo Levels for Obtaining Frequency-dependent Intensity Data from 0.6MHz and 1.0MHz Devices Poerbandono, R.; Suprijo, Totok
Journal of Engineering and Technological Sciences Vol 45, No 2 (2013)
Publisher : ITB Journal Publisher, LPPM ITB

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (457.688 KB) | DOI: 10.5614/j.eng.technol.sci.2013.45.2.3

Abstract

This investigation aims to propose an attenuation rate for range normalization of echo amplitudes recorded by an acoustic backscattering instrument working at a frequency of 1.0 MHz. The intention of the use of such an attenuation rate is to obtain equal echo levels when using a device from the same family of products with a different working frequency, i.e. a 0.6 MHz instrument, at an identical site. This work is based on a field experiment with a 1.0 MHz Acoustic Wave and Current (AWAC) profiler and a 0.6 MHz Aquadopp profiler. Both profilers were deployed upward, side-by-side in the Semak Daun reef lagoon, Seribu Islands, Java Sea, Indonesia. It was found that the proposed attenuation rate for the 1.0 MHz instrument was one-order magnitude higher with respect to the one used for the 0.6 MHz instrument, and logarithmically depth dependent. The proposed attenuation rate for the 1.0 MHz AWAC is –7.925log(R) + 8.551, with R is the slant range from the transducers to the measured layer. Accordingly, the overall agreement between the 1.0 MHz AWAC echo amplitude and the one recorded by the 0.6 MHz Aquadopp was improved by 18dB, which is quite significant considering that the average echo amplitude discrepancy recorded by each transducer was 2.4dB.
Pemodelan Sebaran dan Waktu Tinggal Limbah Panas di Teluk Bontang Suprijo, Totok; Romawan, Francis Seravino; Nur, Ashadi Arifin; Mandang, Idris; Napitupulu, Gandhi
Jurnal Teknik Sipil Vol 31 No 3 (2024): Jurnal Teknik Sipil - Edisi Desember
Publisher : Institut Teknologi Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/jts.2024.31.3.9

Abstract

Abstract The water mass exchange process between a bay and an open sea can flush effluents or pollutants that enter the bay. This paper describes a two-dimensional numerical modelling study on thermal water dispersion due to hydrodynamic processes in The Bontang Bay and the bay flushing capability. The numerical model used is Delft3D. Model input data was including bathymetry, water elevation, discharge of seawater intake and outfall, wind speed, and temperature of the thermal water effluent discharged into Bontang Bay. The modelling results were verified with observation data. Verification results shows that error of water elevation is 0.07 m, while current speed error is 0.26 m/s. Dispersion modeling results indicate that 40°C thermal water discharged at a rate of 24.6 m³/s into Bontang Bay has increased the water temperature in the bay by 1°C to 2°C. This increase in temperature potentially has a negative impact on aquatic ecosystems. An increase in water temperature of 1°C and 2°C covers areas of 19.32 km² and 7.26 km² in the bay, respectively. The residence time of thermal water in Bontang Bay is 3 days and 12 hours before flushing. Keywords: Thermal dispersion, exchange process, residence time, flushing time
ANALISIS PERUBAHAN GARIS PANTAI AKIBAT PEMBANGUNAN JETTY DI WILAYAH PANTAI KARANGSONG, INDRAMAYU, INDONESIA Abdurrahman, Umar; Ningsih, Nining Sari; Suprijo, Totok; Tarya, Ayi
Bulletin of Geology Vol 5 No 2 (2021): Bulletin of Geology
Publisher : Fakultas Ilmu dan Teknologi Kebumian (FITB), Institut Teknologi Bandung (ITB)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.5614/bull.geol.2021.5.2.5

Abstract

Pada tahun 2005 dilakukan pembangunan jetty di muara Sungai Prajagumiwang, tepatnya di Pantai Karangsong, Desa Karangsong, Kecamatan Indramayu, Kabupaten Indramayu, JawaBarat. Pembangunan jetty ini merupakan salah satu solusi dari permasalahan pendangkalan alur pelayaran di wilayah tersebut. Selain berdampak pada aktivitas perikanan setempat, pembangunan jetty ini juga berdampak pada perubahan garis pantai di Pantai Karangsong. Pada penelitian ini, analisis perubahan garis pantai dilakukan dengan memanfaatkan data citra satelit dari Google Earth yang terdiri daritahun 2001, 2008, 2009. 2013, 2014, 2015, 2016, dan 2017. Garis air tinggi dipilih sebagai indikator penentu garis pantai dengan tujuan untuk meminimalisir kesalahan yang dapat terjadi akibat penentuan garis pantai secara manual. Hasil analisis secara kualitatif dan kuantitatif menunjukkan adanya pola perubahan garis pantai yang semula didominasi oleh terjadinya erosi, setelah pembangunan jetty berubah menjadi didominasi oleh akresi. Berdasarkan analisis perubahan luas dan garis pantai yang dilakukan pada penelitian ini, perubahan luas pantai dan garis pantai terbesar terjadi pada periode 2001 –2008 yaitu sebesar 297.136 m2dan 13.897 m. Pada periode 2008 –2017 nilai perubahan luas dan garis pantai menunjukkan kondisi yang berubah ubah dan perubahannya semakin mengecil. Hal ini menunjukkan Pantai Karangsong mengalami proses pantai menuju setimbang. Kata kunci:Perubahan garis pantai, pembangunan jetty, Pantai Karangsong, Google Earth
Transformasi Gelombang Reguler Akibat Pemecah Gelombang Tiang Pancang Dua Baris Selang-Seling Suprijo, Totok; Napitupulu, Gandhi; Ginting, Juventus W.R.; Simanjuntak, Eduardo M.; Abdullah, Faizal A.R.; Khadami, Faruq
JURNAL TEKNIK HIDRAULIK Vol 15, No 2 (2024): JURNAL TEKNIK HIDRAULIK
Publisher : Direktorat Bina Teknik Sumber Daya Air, Kementerian Pekerjaan Umum dan Perumahan Rakyat

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32679/jth.v15i2.787

Abstract

Hydraulic experiments in a two-dimensional physical laboratory were conducted to evaluate the performance of pile breakwaters in reducing wave energy. The piles on the breakwater were arranged in a staggered pattern in two rows. A total of seventy-two simulation scenarios were run based on variations in the incoming wave height and period, and the spacing between the piles, using a 1:10 model scale. The data from the hydraulic tests were then processed using a spectral method that could separate the energy spectra of reflected and transmitted waves. These changes result in reflected and transmitted waves. The laboratory test data were used to estimate the values of the transmission coefficient and reflection coefficient. Both coefficients were then used to validate semi-empirical formulas for the two coefficients. The semi-empirical formulas for the two coefficients were developed based on a model for estimating the spatial porosity of pile breakwaters. The porosity estimation model takes into account the dimensions of the piles and the dimensional components of the breakwater, including the arrangement, number of rows, and spacing between the piles. The validation results of the semi-empirical formulas with the laboratory test data showed a coefficient of determination of 0.917 and a root mean square of 0.077. The staggered arrangement improves the effectiveness of the breakwater in reducing the transmission wave height. The developed semi-empirical model can be used to design the pile dimensions to achieve optimal reflected and transmitted wave heights for coastal protection. Keywords:  pile breakwater, coastal protection, hydraulic experiment, physical wave simulation, wave transmission new formula
SEASONAL AND INTRA-SEASONAL VARIABILITY OF OCEAN THERMAL POTENTIAL ENERGY IN THE INDONESIAN EXCLUSIVE ECONOMIC ZONE Suprijo, Totok; Napitupulu, Gandhi; Ningsih, Nining Sari; Sinaga, Denny Basardo Jonatan; Rachman, Audi
BULLETIN OF THE MARINE GEOLOGY Vol 39, No 1 (2024)
Publisher : Marine Geological Institute of Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32693/bomg.39.1.2024.866

Abstract

Ocean thermal energy is a promising marine renewable energy resource that can be developed as a clean energy alternative for Indonesia, which is in the equatorial or tropical region. This study assesses the potential of ocean thermal energy as a renewable energy source in the Indonesian Exclusive Economic Zone (EEZ) by estimating the monthly, seasonal, and intra-seasonal variability of ocean thermal energy conversion (OTEC) resources. The Indonesian EEZ spans from 6°N to 11°S and 95°E to 139°E, covering an area of 3,495,698.72 km². Using temperature data from simulations of the Hybrid Coordinate Ocean Model (HYCOM), the study evaluates the potential of OTEC resources over a 50-year period (from January 1964 to December 2013) with a spatial resolution of 0.125°. Estimation of OTEC potential power resources was based on temperature differences at depths of 20 m and 1000 m, following the hybrid cycle working principle.The results of the estimations indicate that the area has a monthly average potential power of 289.73 GW. The estimation also reveals seasonal and intra-seasonal variability in this potential energy, with fluctuations ranging from 280.09 GW in August to 295.65 GW in December, influenced by phenomena such as ENSO (El Niño Southern Oscillation) and IOD (Indian Ocean Dipole). In the Indonesian EEZ, the average potential thermal power decreases to 288.23 GW during an El Niño event and increases to 291.72 GW during a La Niña event. The IOD phenomenon has a similar effect, with potential decreasing to 281.82 GW during a positive IOD event and rising to 292.64 GW during a negative IOD event.
Kajian Perilaku Gelombang Akibat Adanya Struktur Tiang Pancang Silinder melalui Analisis Spektrum Energi: Study of Wave Behavior due to Cylinder Pile Structure Through Energy Spectrum Analysis Suprijo, Totok; Khadami, Faruq; Abdullah, Faizal Ade R.; Sesami, Hening; Poerbandono; Prasetyo, Adi; Ginting, Juventus; Simanjuntak, Eduardo; Napitupulu, Gandhi
Jurnal Ilmu dan Teknologi Kelautan Tropis Vol. 15 No. 1 (2023): Jurnal Ilmu dan Teknologi Kelautan Tropis
Publisher : Department of Marine Science and Technology, Faculty of Fisheries and Marine Science, IPB University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29244/jitkt.v15i1.42612

Abstract

Struktur pemecah gelombang banyak dimanfaatkan untuk perlindungan pantai dari hantaman gelombang laut yang berpropagasi ke daerah pesisir pantai. Salah satu inovasi pemecah gelombang yang sedang dikembangkan yaitu struktur tiang pancang. Tiang pancang merupakan replikasi batang pohon bakau yang dapat meredam energi gelombang. Tujuan dalam penelitian ini untuk menganalisis efektivitas struktur tiang pancang dengan menganalisis perilaku gelombang sebelum dan sesudah bertabrakan dengan struktur tiang pancang berdasarkan pembagian teori gelombang. Simulasi laboratorium fisik telah dilakukan untuk mendapatkan data gelombang yang berinteraksi dengan struktur tiang pancang. Selanjutnya, dilakukan analisis spektrum energi untuk menentukan spektrum energi gelombang datang, refleksi dan transmisi dari pengukuran wave probe berupa data time series. Masing-masing spektrum energi digunakan untuk melihat kemampuan refleksi dan transmisi dari struktur tiang pancang dari koefisien refleksi dan transmisi. Nilai koefisien refleksi dan transmisi diestimasi dengan persamaan polinomial derajat tiga menghasilkan dan dengan variabel parameter dasar gelombang yaitu tinggi gelombang, periode gelombang dan kedalaman perairan. Titik kritis dari persamaan polinomial menunjukkan nilai koefisien refleksi dan transmisi minimum ketika berada pada daerah Cnoidal dan maksimum ketika berada pada daerah Stokes orde-2.
Co-Authors Abdullah, Faizal A.R. Abdullah, Faizal Ade R. Abdurrahman, Umar Adi Prasetyo Ayi Tarya Ginting, Juventus Ginting, Juventus W.R. Idris Mandang, Idris Khadami, Faruq Napitupulu, Gandhi Nining Sari Ningsih Nur, Ashadi Arifin Poerbandono Poerbandono, Poerbandono Rachman, Audi Romawan, Francis Seravino Sesami, Hening Simanjuntak, Eduardo Simanjuntak, Eduardo M. Sinaga, Denny Basardo Jonatan