JURNAL SAIN DAN TEKNOLOGI

PENINGKATAN KESUBURAN PERAIRAN LAUT ARAFURA DAN SEKITARNYA PASCA SIKLON TROPIS LAM

Eko Susilo — 2022-10-13

Siklon tropis merupakan fenomena atsmosfer yang ditandai muncul tekanan udara rendah yang memicu terjadinya angin yang kencang akibat proses perpindahan panas dari daerah khatulistiwa menuju garis lintang. Dampak siklon tropis sangat dirasakan oleh daerah pesisir dan daratan baik berupa meningkatnya curah hujan, bencana banjir hingga kerusakan infrastruktur. Namun siklon tropis menjadi salah satu faktor yang pemicu terjadinya pengadukan vertikal dan upwelling yang menyebabkan meningkatnya kesuburan perairan. Penelitian ini bertujuan untuk mengetahui tingkat kesuburan perairan di Laut Arafura dan sekitarnya pasca terjadinya siklon tropis LAM yang menerjang perairan Arafura dan pantai Queensland Australia pada tanggal 19 Februari 2015. Hasil analisis data konsentrasi klorofil-a komposit 8 harian satelit Aqua Modis menunjukkan daerah yang dilalui oleh siklon tropis LAM mengalami peningkatan kesuburan namun dengan respon yang berbeda pada masing-masing area pengamatan. Nilai konsentrasi klorofil-a sebelum terjadi siklon berkisar antara 0,71 mg/m³ - 0,76 mg/m³ dan mengalami peningkatan hingga 5 kali lipat pada kisaran 3,72 mg/m³ dan 4,15 mg/m³. Jeda waktu peningkatan kesuburuan bervariasi dari beberapa hari (A1, A2 dan A4) hingga selang 2 minggu (A3) pasca siklon LAM. Sedangkan berdasarkan data Global High Resolution Sea Surface Temperature (GHRSST), suhu permukaan laut mengalami penurunan tertinggi mencapai 1,14^oC dalam kurun waktu 2-3 hari pasca siklon tropis LAM, khususnya pada area A3 yang merupakan lokasi terjadinya siklon dewasa sebelum bergerak memasuki daratan.

KAJIAN EKSPERIMENTAL PENGGUNAAN BAHAN BAKAR BIOSOLAR PADA MESIN DIESEL DUAL FUEL BERBAHAN BAKAR BIOSOLAR DAN CNG

Suardi — 2022-10-13

Various studies on optimizing fuel for diesel engines has been done and one of them is the combination of the fuel system between oil and gas. One is the design process fuel gas supply system for diesel engines DDF (Dual Fuel) Natural Gas - Biodiesel, on the research amount of diesel fuel which is in fixed supply 100% then added supply of natural gas by 20%. Based on test results, CNG is able to substitute up to 75% Biodiesel needs. This research is the development of research on where to early stages of the overall research on experimental studies fuel use dual fuel in diesel engines. This stage will focus on the design engineering Biodiesel fuel system with fuel supply capacity expected Biodiesel is 80% plus 20% more CNG. The installation process machine DDF is slightly different from the installation of the machine in general because of the process of controlling the machine itself will use a control device automation is expected to set the timing and injection of gas while on the installation Biosolarnya modification of the injector so that consumption Biosolarnya can be reduced until it reaches the level of the composition of the fuel ideal. The results of this study will menghasilakn than levels pencapuran most optimal fuel when measured from the level of engine performance resulting in power, SFC and better thermal efficiency than the use of pure Biodiesel.

OPTIMALISASI PENGGUNAAN BAHAN BAKAR PADA MESIN INDUK DUAL FUEL PADA KAPAL CNG CARRIER RUTE GRESIK-LOMBOK MENGGUNAKAN METODE MULTI-OBJECTIVE GENETIC ALGORITHM (MOGA)

Adhi Iswantoro — 2022-10-14

Lombok Island increased consumption of electrical energy. To meet the demand for electricity on the island of Lombok, the government through PT PLN (Persero) using diesel (Diesel Power Plant). The problem that arises is the operational cost of diesel to be very large, especially if the peak load during limited hours. So that makes PT PLN must provide a generator unit that is a lot more to overcome it. This is the problem, because the consumption of fuel for diesel engines is also increasing. Therefore planned during peak hours, which is 5 hours with a diesel power plant using gas turbine fuel Compressed Natural Gas while the diesel engine is turned off. Other new problems, how the CNG distribution systems from the source to the user. Given the CNG supply taken from outside the island of Lombok because Lombok Island no gas resources and production facilities. Here PT PLN has initial plans for CNG distribution system to the island of Lombok is using specialized vessels transporting CNG. Because if you use a subsea pipeline would be very ineffective. Where the ship is also using a dual fuel engine that vessel operating costs can be reduced. This research will focus on optimizing the use of the fuel in ship main engine dual fuel CNG Carrier. The method used in this study is a multi-objective genetic algorithms.

PENGEMBANGAN SERIES BENTUK LAMBUNG SELF-PROPELLED BARGE

Achmad Baidowi — 2022-10-14

In a period of 10 years (2003-2013) there are 140 construction Self-Propelled Barge (SPB) in Indonesia. However, there is currently no standard for ship hull design SPB twin screw is widely used in Indonesia so that ships SPB experience problems such as vibration, a big obstacle. This research will develop the 27 series hull shape SPB through variation Cb ratio L / B, B / T, L / H and H / T based parent hull-form. One goal is to get a size variation SPB hull form which is more efficient in terms of ship obstacles. The resistance is calculated based on the potential flow theory with slender body approach method. But besides the use of slender body theory is also used Holtrop method to estimate the barriers. Selection of the hull form block, considered the most optimal value based on the smallest obstacles amongst the 27 series.

SEACELL (SEA WATER ELECTROCHEMICAL CELL) PEMANFAATAN ELEKTROLIT AIR LAUT MENJADI CADANGAN SUMBER ENERGI LISTRIK TERBARUKAN SEBAGAI PENERANGAN PADA SAMPAN

Siti Fariya — 2022-10-14

The Petroleum consumption tends to increase from year to year. From this threat, energy experts estimate, that fossil fuels will run out at a certain time consumed. Diesel fuel is the fuel used by fishermen to turn on the generator set at sea. However, the presence of diesel fuel is currently limited and expensive. Besides that, diesel fuel can cause carbon emissions, and the resulting emissions include SOx, NOx, CO, HC, and particulate dust. For this time, the solution there is to replace diesel with biodiesel. The existence of biodiesel is not an appropriate solution because the prices are not much different from the solar. So that required an appropriate solution to replace fuel oil, like diesel fuel. On the other hand, sea water is a mixture of 96.5% pure water and 3.5% other materials such as salts and dissolved gases. Basically, the sea water contains a compound of high NaCl and by H₂O is decomposed into Na⁺ and Cl^-. With the existance of free particles, it can generate electricity. The emergence of electric current by the free charge can be used as a source of electrical energy that is cheap and environmentally friendly with method voltaic cells. Tues voltaic can convert chemical energy arising from the reaction of Na + and Cl-into electrical energy. Therefore, the authors provide a solution that named is "SEACELL (Sea Water Electro Chemical Cell): Utilization of Electrolyte of Sea Water Being Renewable Sources of Energy Electrical as change Generator Set to Lighting on Sampan". Design SEACELL made with an open system for the ions of sea water keep flowing during operation SEACELL. How it works SEACELL is when the sea water entering and flowing into the SEACELL, ion of the salt NaCl terkadung in sea water breaks down into Na + and Cl-so resulting the anode and cathode reaction. Negative ions from the salt will oxidize Pb electrode, causing a potential difference between electrode Pb with NaCl solution. That's the thing that causes an electrical current. Voltage generated from SEACELL theoretically capable of 15 volts per 1 kg of sea water.

PENENTUAN STANDAR WAKTU PODUKSI POKOK PROSES PENGELASAN MIG (METAL INERT GAS) LOGAM ALUMINIUM ALLOY 5083 PADA PEMBANGUNAN KAPAL

Achmad Fausi — 2022-10-14

On the shipbuilding process nearly 80% of the job is welding, where the skills andcompetence is very influential in the completion of welding work. Standard time welding work is urgently needed in order to find out the length of time the welding job overall. In this research, it aims to define the time standart main production of welding MIG aluminum plate for butt joint on the position down hand (1G), horizontal (2G), vertical up (3G) and fillet joint on the position down hand (1F), horizontal (2F), vertical up (3F) in the process of making aluminum boats. The Data obtained with measurement and observation in the field directly on the aluminum vessel welding work, Then the data processed and analysed using the statistical method which is one of the ANOVA (analysis of Variance) by using the SPSS program assistance 16.0 for windows (Statistical Program for Science), so that the equation obtained time standart of welding on the position 1G Y = 7,79 X + 56,79, position 2G Y = 10,49 X + 62,11, position 3G Y = 7,421 X + 73,59, position 1F Y = 8,71 + 58,58, position 2F Y = 4,235 X + 83,01 and position 3F Y = 7,636 X + 71,79.

RANCANG BANGUN MESIN PENGERING SENTRIFUGAL PADA PROSES PENGGILINGAN SAMPAH PLASTIK JENIS POLYETHYLENE THEREPHTHALATE (PET)

Engki Andri Kisnarti — 2022-10-14

One solution to the problem of waste in particular types therephthalate polyethylene (PET) plastic and is chopping and drying. But still drying system uses natural forces that rely on solar energy. The purpose of this paper is to implement the theory of centrifugal force and gravity in centric tools plastic dryer (centrifugal dryer) that can be produced by a centrifugal drying machine. The method used in the manufacture of centrifugal drying machine is to utilize the principle of centrifugal force and gravity. Resulting in a drying machine that is able to work and produce 2,880 kg for one day (8 hours).

KAJIAN POTENSI SUHU AIR LAUT PERAIRAN PULAU TARAKAN DAN BUNYU SEBAGAI SUMBER ENERGI TERBARUKAN

Sugeng Riyanto — 2022-10-14

Tarakan is an area of territory which lies north Borneo and consists of nearby islands. Some of its sea territory can be exploited as renewable fuels or renewable energy. In this research, Ocean Thermal Energy Conversion (OTEC) is a thermal energy conversion temperature of sea water into electrical energy by the temperature difference use surface sea water temperature and the water temperature in the sea. The surface temperature of the sea water which is located Tarakan and Bunyu region between 26.7 up to 30.2 with a depth of 30 to 100 meters produce the greatest efficiency is 0.17.

ANALISIS KELAYAKAN FINANSIAL USAHA PENDEDERAN BENIH IKAN KERAPU SUNU, Plectrpomus leopardus

Anak Agung Alit — 2022-10-14

Financial analysis efforts fish fry kerapu sunu, Plectrpomus leopardus been done at the hatchery in January to April 2015 in the area of the village of Musi, and the village Sanggalangit Gerokgak Kab. Buleleng, Bali. Research approach the rapid rural appraisal (RRA) and direct interviews with growers of fish fry kerapu sunu. Data related to the technical aspects of the farmer directly, and the economic analysis in the guides to venture into the field of primary data obtained were analyzed using the approach of business profits, the value of breakeven, and business investment payback period. The results research that the seed nursery business kerapu sunu fish in the hatchery provides a profit of Rp 27.158 million, - per 2 months for a period of maintenance, using as many as 10 pieces tub. Investment needed for today is USD 83.4 million, -. Value breakeven obtained Rp 14,147,619, - or many as 1,417 of the tail and the payback period is for 2 months or 1 period maintenance. From the analysis of the feasibility of kerapu sunu fish can to be developed as a sustainable fishing effort.