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ABSTRAK
Sumber utama lepasan radioaktif 137Cs yang dikategorikan sebagai global fallout berasal dari percobaan senjata nuklir pada masa lalu serta kecelakaan nuklir PLTN Chernobyl dan PLTN Fukushima yang masing-masing terjadi pada tahun 1986 dan 2011. Kontaminasi radioaktif yang berada di atmosfir akan terdeposisi ke daratan dan terdispersi melalui perairan. Operasional fasilitas nuklir yang telah ada dan rencana pembangunan RDE (Reaktor Daya Eksperimental) di Kawasan Puspiptek Serpong dapat berpotensi melepas radioaktif 137Cs melalui sungai Cisadane dan bermuara ke Teluk Jakarta. Diperlukan pemantauan lingkungan terhadap kandungan radioaktif hasil fisi sebagai kontrol terhadap tingkat radioaktivitas lingkungan laut saat fasilitas nuklir yang direncanakan dan fasilitas yang ada beroperasi. Disisi lain unit yang digunakan memiliki kelemahan efisiensi adsorpsi serta diperlukannya suatu unit yang mudah mobilisasi dan terintegrasi dengan pemantauan kualitas air. Pada penelitian ini telah dibuat alat ekstraksi 137Cs di air laut yang terintegrasi dengan pemantauan parameter air laut seperti pH, konduktivitas dan suhu. Prototipe telah menjalani proses pengujian dan memenuhi pedoman analitik IAEA dengan hasil batas kuantifikasi dan batas deteksi sebesar 0,13 mBq/l dan 0,29 mBq/l serta hasil uji bias relatif dan presisi dibawah batas yang diperbolehkan.

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ABSTRACT
The main source of 137Cs radioactive releases categorized as global fallout came from nuclear weapon experiments in the past as well as nuclear accidents of the Chernobyl and Fukushima nuclear power plant occurred in 1986 and 2011. Radioactive contamination in the atmosphere will be deposited on land and dispersed through the water. The existing operational nuclear facilities and plan to construct an Experimental Power Reactor in the Serpong Puspitek area could potentially release radioactive 137Cs through the Cisadane river and ended in Jakarta bay. Environmental monitoring of fission product is required as control of the level radioactivity of the marine environment when the new nuclear facilities and existing facilities operate. On other hand the unit used has a weakness of adsorption efficeinsy and new unit that easily mobilized and integrated with monitoring of seawater parameter such as pH, conductivity and temperature. The unit have been made integrated with water quality checker and the data from the results can be downloaded on a computer device. This prototipe has been tested and fulfilled IAEA analytical guidelines with the results of decision threshold and detection limit were 0,13 mBq/l and 0,29 mBq/l respectively, also the results of the relative bias and precision test are below the permissible limit.

Abstrak :
Penerapan sistem proteksi korosi menjadi suatu keharusan terhadap konstruksi yang dibangun di daerah yang rawan korosi seperti dermaga (oil wharve) yang berada pada daerah pantai, guna pemeliharaan dan keselamatan khususnya terhadap kerugian akibat serangan korosi yang dari waktu ke waktu semakin besar. Penelitian yang dilakukan ini menitikberatkan pada evaluasi sistem proteksi korosi yang sudah ada pada oil wharves, dimana sistem proteksi yang sudah ada tidak mampu menahan korosi piles khususnya yang berada pada daerah splash dan pada sleeve. Untuk mendapatkan desain proteksi korosi yang optimal dilakukan mengukuran nilai pH air laut, kelarutan oksigen, mengamati kondisi T/R (transformer rectifier), kondisi coating dan pengukuran rapat arus air laut. Kemudian menghitung ulang kebutuhan anoda korban untuk sistem anoda korban, menghitung kebutuhan arus dan potensiaf rectifier untuk sistem arus tanding, dan menentukan alternatif jenis proteksi untuk diaplikasikan pada daerah splash yang mengalami korosi yang cukup tinggi. Tujuan penelitian ini adalah mengevaluasi dan mendesain ulang sistem proteksi korosi yang optimum untuk tiang-tiang pancang (piles) pelabuhan atau dermaga. Hasil penelitian menunjukkan adanya beberapa faktor yang menyebabkan proteksi korosi yang sudah ada tidak berjalan dengan baik, yaitu penggunaan clamp untuk menempelkan anoda korban pada pile, adanya aliran arus dan potensial yang terputus dari rectifier ke struktur, dan kondisi groundbed (menggunakan anoda grafit) yang diperuntukkan untuk melindungi struktur sudah tidak dapat memenuhi fungsinya secara maksimal (termakan usia). Dan penghitungan ulang kebutuhan anoda korban di dapatkan untuk Oil wharf # 1 & #2 membutuhkan 23.03 ton, Oil wharf # 3 membutuhkan 24.00 ton, Oil wharf # 4 membutuhkan 19.07 ton dan MD #1 - #10 membutuhkan 26.82 ton untuk jangka waktu 20 tahun. Anoda korban yang digunakan untuk proteksi katodik ini adalah Sapalum 111 (Galvanum Ill) yang merupakan jenis anoda paduan Aluminium-Zinc-Indium (AI-Zn-In). Pada Sistem proteksi arus tanding pada OW #3 menggunakan kebutuhan arus dan tegangan sesuai dengan desain hasil perhitungan yaitu, iTR =48.81 A , VTR = 19.18 volt dan sistem groundbed yang menggunakan anoda grafit digantikan dengan anoda MMO (mixed metal oxide). Untuk proteksi korosi pada daerah splash menggunakan petrolatum tape dan covering system.

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The implementation of corrosion protection system has become a requirement on the construction built in corroded environment as jetty (oil wharves) on the beach, for maintenance and safety especially on the effect of corrosion attacks, along its life is getting worst. Thesis done to analyze the evaluation of the corrosion protection system which has been installed on it for years, where the protection system can not longer cover the corrosion on piles, especially on the splash area and on sleeve. To gain the optimum corrosion protection design, we measuring the seawater pH, dissolved oxygen, observing T1R condition, coating condition and design current required for CP design. On the next step, we recalculation the need of anode for sacrificial anode system, to calculate the needs of current and potential rectifier for impress current system and then to design protection corrosion for splash area with the high corrosion environment. The result appointed there is some factor causing corrosion protection installed did not work properly, which is the use of clamps to attach the sacrificial anode on piles and current and electricity potential being cut from TIR to structure, and groundbed condition (grafite anode) which is used to protect the structure, can not longer efficient as it was. Recalculation the needs of sacrificial anode on oil wharf #1 and #2 is 23.03 tons, oil wharf #3 need 24.00 tons, oil wharf #4 need 19.07 tons, and MD #1 to #10 need 26.82 tons for 20 years time. Sacrificial anode used on this cathodic protection is Sapalum Ill (Galvanum Ill), which is aluminum alloy (Al - Zn- In). The impress Current Protection system on OW #3 need current 6=48.81 A and volt Vt =19.18 Volt, based on the result of the calculation design, and replace the ground bed graphite anode with MMC, and using Petrolatum tape and covering system on he splash zone.

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Pemenuhan akan kebutuhan air bersih merupakan salah satu masalah global yang diprediksi akan terus meningkat. Penyediaan air bersih di Indonesia terhambat oleh sulitnya akses untuk mendapatkan air bersih dan buruknya kualitas air yang tersedia, khususnya pada daerah atau pulau terpencil. Sebagai negara kepulauan yang memiliki laut cukup luas serta mendapatkan sinar matahari sepanjang tahun, pengembangan alat desalinasi bertenaga matahari adalah salah satu solusi yang dapat ditawarkan untuk permasalahan pemenuhan kebutuhan air bersih di Indonesia.Penelitian ini bertujuan untuk membuat suatu prototipe alat desalinasi bertenaga matahari tipe wick yang memiliki performa baik dengan struktur sederhana dan material yang mudah ditemukan serta harga terjangkau. Proses prototyping dilakukan mulai dari pemilihan material wick, pengujian sistem penyebaran air, hingga proses manufaktur dari komponen-komponen alat desalinasi. Penelitian menghasilkan prototipe alat desalinasi bertenaga matahari tipe wick single deck  yang memiliki dimensi 127,5 cm x 127,5 cm x 10 cm dan berat 14,6 kg dengan harga produksi relatif murah. Berdasarkan pengujian yang telah dilakukan, efisiensi dari prototipe adalah 35,6% dengan sudut inklinasi 30°.

 

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Fulfilling the need for fresh water is one of the global problems which is predicted to continue to increase. Provision of fresh water in Indonesia is hampered by the difficulty of access to clean water and the poor quality of water available, especially in remote area or islands. As an archipelagic country that has wide sea area and gets sun all year round, the development of solar desalination equipment is one of the solutions that can be offered for the problem of meeting fresh water needs in Indonesia.This research aims to create a prototype of a wick type solar desalination that has good performance with simple structures and easy-to-find materials yet affordable prices. The prototyping process is carried out starting from the selection of wick material, testing of the water distribution system, to the manufacturing process of the components of the desalination device. The research produced a wick single deck type solar desalination prototype that has dimensions of 127.5 cm x 127.5 cm x 10 cm and weighs 14.6 kg with relatively low production prices. Based on this research, the efficiency of this prototype is 35,6% with inclination 30°.

 

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This study aims to develop a seawater distiller that can be used to purify water by using electrical energy to power the heating elements used in the condensation phase of distillation. Varying numbers of water heating elements and water levels in the evaporator unit were analyzed to determine the ideal device configuration. The distillation device consisted of a container unit, a water level control unit, and an evaporation chamber unit. Distillation was conducted in two experiments, one with a water level of 8 cm and the other, 4 cm, in the evaporation unit. Each experiment comprised eight tests, in which 1–6 water heating elements were used in various configurations; identical configurations were used in both experiments. The seawater used was obtained from the Indian Ocean off Balekambang Beach, Malang Regency, Indonesia. The largest purified water volume obtained among the 16 experimental conditions was 3.94 L at a cost of IDR 790 per liter. The effectiveness percentage toward water quality improvement in terms of pH, electrical conductivity, TDS, and maximum salinity was 9.88%, 99.98%, 99.96%, and 100%, respectively. In the future, a full-scale experiment will be conducted on site. The use of this device will therefore benefit people in areas with water scarcity.

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Shallow water acoustics (SWA), the study of how low and medium frequency sound propagates and scatters on the continental shelves of the worlds oceans, has both technical interest and a large number of practical applications. Technically, shallow water poses an interesting medium for the study of acoustic scattering, inverse theory, and propagation physics in a complicated oceanic waveguide. Practically, shallow water acoustics has interest for geophysical exploration, marine mammal studies, and naval applications. Additionally, one notes the very interdisciplinary nature of shallow water acoustics, including acoustical physics, physical oceanography, marine geology, and marine biology. In this specialized volume the authors, all of whom have extensive at-sea experience in US and Russian research efforts, have tried to summarize the main experimental, theoretical, and computational results in shallow water acoustics, with an emphasis on providing physical insight into the topics presented.

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Pengamatan terhadap kandungan logam berat dalam air laut dan sedimen telah dilakukan di perairan muara Sungai Cisadane pada bulan Juli dan November 2005. Kadar logam berat dalam air laut lebih rendah dibandingkan di dalam sedimen. Hasil tersebut memperlihatkan bahwa kadar semua logam berat masih sesuai dengan Nilai Ambang Batas baku mutu air laut yang ditetapkan oleh pemerintah bagi biota, selain itu ada indikasi bahwa logam berat tersebut terakumulasi dalam sedimen. Distribusi logam Pb pada bulan Juli dan logam Cu pada November dengan kadar yang tinggi ditemukan di dekat pantai dan menurun ke arah laut dan pada umumnya ditemukan di muka muara sungai yaitu Sungai Cisadane, Muara Saban dan Tanjung Pasir. Distribusi Pb dan Zn pada bulan November 2005 dengan kadar yang tinggi ditemukan hanya di muka muara Sungai Cisadane. Distribusi kandungan Cd di muara sungai Cisadane di semua stasiun merata, tetapi tidak menunjukkan korelasi antara kadar Cd dengan jarak stasiun terhadap muara. Terlihat bahwa kandungan Cd secara keseluruhan pada bulan Juli dan November 2005 kurang dari 0,001 ppm. Secara umum, kandungan logam berat antar stasiun di lokasi pengamatan menunjukkan distribusi yang seragam, baik stasiun yang berdekatan dengan muara sungai maupun stasiun yang jauh dari muara sungai.

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Heavy Metallic Element Distribution in Cisadane River Estuary?s Water and Sediment. Observation of heavy metallic elements in Cisadane River Estuary has been done in July and November 2005. The results show that heavy metallic elements content in seawater is lower and still below the treshold value stated by government for fisheries. There was an indication of heavy metallic elements on sediment. Distribution of Pb on July and of Cu on November 2005 were found higher near the coast and decrease towards the sea, and commonly were found in front of estuary such as Cisadane, Muara Saban and Tanjung Pasir. High Pb and Zn distributions on November 2005 were found only in front of Cisadane estuary. Cd distribution of Cisadane estuary was constant at all station but did not show any correlation with the distance of station and estuary. The Cd content on July and November 2005 is lower than 0,001 ppm. Generally, heavy metallic elements content have a uniform distribution at all stations inspite of its distance to estuary.

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This study focuses on an evaluation of the dynamic modeling and discharge performance of magnesium battery activated by sea water. Modeling is important to determine the optimum condition of battery discharge operation. The modeling was performed by modifying the Shepherd model approach by combining an Rint equivalent circuit model to avoid the looping algorithm problem. Initial parameters were obtained from battery discharge manufacturing data on open operating systems. The battery anode used magnesium foil, the cathode used carbon, while the electrolyte used 3.5%wt NaCl solution. The battery discharge test to obtain manufacturing data was carried out with variations in current loads of 0.01 C, 0.05 C and 0.1 C until the potential and current were zero. Battery discharge performance evaluation can also be performed from manufacturing data analysis. Potential battery discharge decreased from ±1.49 V to ±1.30 V, while the battery discharge potential was relatively stable at ±1.30 V to the SOCmin potential value (±1.29 V). It can be seen from the different values of exponential and nominal potential that the parameters were not too significant. The modeling has convergence on the discharge parameters, such as E0 = 1.303 V; R = 0.012 Ω; Kdr = 0.01 Ω; Kdv = 5.794×10-4 V/A.h A = 0.195 V; and B = 140 (A.h)-1 . The SOCmin value of 5% indicates a minimum limit of battery operation that is permitted for battery performance to drop suddenly. The SOCmax value of 93% indicates the maximum allowable limit for the battery to operate stably. The percentage of simulated data error compared to the manufacturing data is 0.85%.

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ABSTRAK
Intrusi air laut merupakan salah satu masalah kualitas air tanah yang dapat dimodelkan secara matematika. Model matematika diformulasikan dalam bentuk persamaan diferensial parsial yang kemudian solusi persamaan dapat dilakukan secara numerik. Tujuan utama dari penelitian ini adalah menyimulasikan secara numerik intrusi air laut pada suatu akuifer terkekang. Untuk menyimulasikan intrusi air laut, diperlukan persamaan aliran air tanah dependent-density atau persamaan air tanah yang mengakomodir perubahan massa jenis terhadap ruang dan waktu. Penelitian ini menggunakan persamaan aliran air tanah dependent-density yang pernah dikembangkan oleh Kurnia (2012). Persamaan lain yang diperlukan adalah persamaan transpor adveksidispersi dan gradien perubahan massa jenis terhadap perubahan konsentrasi. Diskritasi persamaan diferensial menggunakan metode Finite-Difference melalui skema Alternating Direction Implicit (ADI). Simulasi model dilakukan dengan menyusun program pada bahasa Visual Basic for Application (Excel-VBA). Model diperlakukan dengan 2 kondisi simulasi yaitu tanpa dan dengan pemompaan akuifer. Hasil akhir simulasi menggambarkan kondisi model sebelum dan setelah intrusi air laut sesuai dengan kodisi teoritisnya.

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ABSTRACT
Seawater intrusion is one of the groundwater quality problems which can be simulated as a mathematical model. The mathematical model is formulated as the partial differential equation (PDE) and the solution of the PDE is obtained numerically. The Main objective of this research to simulate seawater intrusion phenomena numerically in the confined aquifer. Dependent-density groundwater flow model is necessary to simulate seawater intrusion phenomena. This research employs the dependent-density groundwater flow model which developed by Kurnia (2012). The other equations to complete simulation are advection-dispersion transport model and the gradient of the changes of fluid density to the changes of concentration constituent. Discretization of PDE is conducted using the Finite-Difference method through Alternating Direction Implicit (ADI) scheme. Simulation is conducted by developing computer programming. Visual Basic for Application (Excel-VBA) is chosen for this research. There are 2 conditions of simulation follows without and by pumping aquifer. The final result of simulation describes both of the model condition, before and after pumping aquifer are appropriate to the theoretical condition.

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Jakarta merupakan Ibukota Negara Kesatuan Republik Indonesia dan menjadi kota metropolitan terbesar. Untuk kegiatan sehari-hari, jumlah air bersih yang dibutuhkan masyarakat Jakarta sangatlah banyak. Salah satu sumber air bersih yang digunakan adalah air sumur. Namun, pada beberapa wilayah Jakarta air sumurnya tidak dapat digunakan karena terkontaminasi oleh air asin. Isu mengenai air asin di Jakarta sudah menjadi perbincangan para peneliti. Meskipun demikian, para peneliti masih memperdebatkan sumber dari air asin tersebut. Ada dua pendapat mengenai sumber air asin di Jakarta, yaitu berasal dari intrusi air laut dan berasal dari air fosil. Penelitian ini bertujuan untuk mengidentifikasi keberadaan intrusi air laut yang menjadi penyebab asinnya air tanah di Jakarta. Metode yang digunakan adalah First Horizontal Derivative (FHD) pada data time-lapse mikrogravitasi dan dikorelasikan dengan data sekunder berupa sampel air tanah. Pergerakan suatu fluida di bawah permukaan dapat diketahui dari nilai FHD. Hasil yang didapatkan menunjukkan adanya aliran fluida yang berarah barat laut – tenggara maupun timur laut – barat daya. Berdasarkan arah aliran fluida tersebut, dapat disimpulkan bahwa penyebab air asin di Jakarta adalah air laut yang terintrusi ke daratan. Intrusi air laut tersebut mengalir dan menyebar ke beberapa daerah di Jakarta. ......Jakarta is the capital city of Indonesia and also the largest metropolitan city. For daily activities, the amount of clean water needed by the people of Jakarta. One of the sources that used for clean water is groundwater. However, in several areas of Jakarta the groundwater cannot be used because it is contaminated by salt water. The issue of salt water in Jakarta has become a topic of discussion among researchers. But researchers are still debating the source of salt water. There are two opinions regarding the source of salt water in Jakarta, namely that is comes from sea water intrusion and it comes from connate water. This research aims to identify the presence of sea water intrusion which is the cause of the salty groundwater in Jakarta. The method used is First Horizontal Derivative (FHD) on time-lapse microgravity data and groundwater sample for the secondary data. The groundwater fluid movement can be known from the time-lapse FHD value. The results obtained indicate that there is a fluid flow in a northwest – southeast and northeast – southeast direction. Based on the direction of the fluid flow, it can be concluded that the cause of the salt water in Jakarta is sea water intruding onto land. The sea water intrusion flows and spreads to several areas in Jakarta.