Tujuan dari penelitian ini adalah mengetahui pengaruh frekuensi pemberian minyak ikan dalam medium kultur terhadap sintasan dan perkembangan larva kerapu bebek (Cromileptes altivelis) yang pemeliharaannya dilakukan secara massal. Penelitian dilaksanakan dengan menggunakan bak fibervolume 200 L. Ke dalam bak diisilarva yang baru menetas (Dl) dengan kepadatan 10 ekor/L.
Salah satu kendala yang menyebabkan tingginya kematian larva pada pemeliharaan kerapu adalah besarnya ukuran pakan larva awal yang tidak sesuai dengan bukaan mulut larva, jenis, dan jumlah pakan yang diberikan. Penelitian ini bertujuan untuk mengetahui penggunaan nattplius Acaftia sp. sebagai pakan awal pemeliharaan larva kerapu bebek.
<em>The purpose of this research </em><em>is to determine the effect of heat treatment hardening of Al</em><em>Mg</em><em>Si</em><em>-</em><em>Fe12% casting aluminium alloys</em><em> </em><em>on wear. The tests were carried out on specimens of raw materials and heat-treated specimens with variations of temperature used were 550 <sup>o</sup>C, 575 <sup>o</sup>C, 600 <sup>o</sup>C, and 625 <sup>o</sup>C, and used 15 minutes of holding time in each heat treatment, then quenching in SAE 20 oil. The method used for wear-tested was high speed ogoshi universal testing machine wear.</em><em> The result had shown on </em><em>raw material a specific wear rate was 2.256102E-07 mm<sup>2</sup>/kg. Test results on the </em><em>specimens</em><em> that have</em><em> received heat treatment hardening temperature 550 <sup>o</sup>C increased the wear value decreased to 1.7471E-07 mm<sup>2</sup>/kg. In materials with temperature heat treatment, 575 <sup>o</sup>C causes wear values were increased when compared with raw material, </em><em>respectively, 2,83739E-07 mm<sup>2</sup>/kg. In materials with temperature heat treatment 600 <sup>o</sup>C also causes wear values were increased when compared with raw material, respectively, 2,65105E-07 mm<sup>2</sup>/kg. Test results on the test material that ha</em><em>s</em><em> received heat treatment temperature 625 <sup>o</sup>C increased the wear value decreased to 2.16777E-07 mm<sup>2</sup>/kg.</em>
ABSTRAKDengan keberhasilan produksi benih kerapu bebek, masih banyak kendalakendala yang harus diperbaiki di antaranya kualitas benih, yaitu morfologi benih kerapu bebek dari hasil produksi perbenihan masih ada yang cacat seperti insang terbuka, mulut bengkok, tulang belakang bengkok, dan sebagainya yang akan mengganggu pertumbuhan bila dibudidayakan, selain mempunyai harga yang murah dan rentan terhadap penyakit. Diduga salah satu penyebab cacat adalah tidak berkembangnya gelembung renang pada larva yang diakibatkan ketidakmampuan larva mengambil udara di permukaan air yang tertutup oleh lapisan minyak. Karena itu untuk membersihkan lapisan minyak di permukaan air perlu adanya penelitian penggunaan skimmer dengan waktu yang berbeda yaitu: saat larva berumur 6 hari; 15 hari, dan tanpa skimmer. Hasil yang diperoleh adalah penggunaan skimmer pada larva berumur 6 hari menghasilkan sintasan dan pertumbuhan lebih baik di samping mempunyai persentase perkembangan gelembung renang yang lebih tinggi dan persentase benih yang cacat lebih rendah dibanding dengan perlakuan yang lain.
ABSTRACT:Effect surface skimmer on deformity of humpback grouper (Cromileptes altivelis) larval rearing.
<p><em>The purpose of this research is to know the effect of Heat Treatment Hardening-Tempering Alloy AlMgSi–Fe12% foundry result to hardness and toughness. The test was carried out on raw material and material test specimen after obtaining Hardening heat treatment at 600</em>℃ <em>and quenching with SAE 20 oil medium. While Tempering variation at temperature 200</em>℃<em>, temperature 250</em>℃ <em>and temperature 300</em>℃ <em>with detention time for 15 min at each temperature, each heat treatment. Hardness testing method is done by standard micro Vickers test method with 100 gf loading. The result of raw material testing for hardness value is 60,92 VHN. Test results after heat treatment process at temperature 200</em>℃ <em>cause hardness value increased by 63,50 VHN. At temperature 250</em>℃ <em>cause hardness value decreased to 59,94 VHN. At temperature 300</em>℃ <em>cause hardness value increase to 76,98 VHN </em></p>
Berdasarkan data Badan Pusat Statistik, jumlah penduduk Indonesia meningkat sangat pesat daritahun 2000 hingga 2010 sebesar 31.376.731 jiwa. Peningkatan jumlah penduduk berbanding lurus dengankonsumsi listrik. Untuk memenuhi kebutuhan pasokan listrik pemerintah membangun berbagai pembangkitlistrik, salah satunya pembangkit listrik tenaga uap (PLTU). Upaya peningkatan potensi effisiensi PLTUdilakukan dengan meningkatkan koefisien perpindahan kalor dua fasa. Penelitian ini bertujuan untukmengetahui pengaruh debit air, debit udara dan kemiringan pipa terhadap koefisien perpindahan kalor duafasa pola aliran gelembung. Penelitian ini dilakukan dengan mengalirkan udara dengan debit 20 cm3/menit,40 cm3/menit dan 60 cm3/menit. Mengalirkan air dengan debit 2 LPM, 4 LPM dan 6 LPM. Penelitimenggunakan pipa tembaga panjang 2.200 mm dengan diameter dalam 14 mm dan diameter luar 16 mm.Pipa tersebut dipanaskan dengan nikelin berdiameter 0,8 mm yang dibuat melingkari pipa sepanjang 2.000mm. Pada pipa tersebut dipasang 4 buah termokopel untuk membaca suhu yaitu input air, output air, inputdinding pipa tembaga, dan output dinding pipa tembaga. Hasil penelitian menunjukan bahwa terdapatpengaruh positif fraksi hampa pada pipa sempit dengan permukaan dalam berbentuk spiral terhadapterhadap koefisien perpindahan kalor. Pertambahan nilai fraksi hampa menghasilkan gelembung yangjumlahnya lebih banyak, keberadaan permukaan dalam berbentuk spiral mengakibatkan gerakan gelembungsemakin acak dan lebih merata pada permukaan melintang pipa. Dua faktor ini menghasilkan peningkatankoefisien perpindahan kalor.
<p><em>The Cylinder sleeve is an engine component that is mounted on the cylinder block which functions as a piston glide base. The cylinder sleeve is made of FC250 gray cast iron. FC250 is a gray cast iron that has lamellar graphite with a tensile strength of at least 250 MPa. This study aims to determine the mechanical properties of hardness and wear of the Cylinder Sleeve made of gray cast iron FC250. The method used in this research is gray cast iron which is cut with a length of 5.5cm, thickness 0.7cm, height 0.7cm which is formed according to the standard size of the hardness and wear test. The tests carried out include testing brinell hardness and wear. The results showed that the lowest hardness value was 134.63BHN and the highest hardness value was 191.43BHN. The increase in hardness values is influenced by the carbon content that cannot be spread evenly, which is followed by a fast cooling rate. The results of the wear test obtained the lowest price of 0.00017mm³/kg.m and the highest wear price of 0.00028 mm³/kg.m.</em></p><p><em><br /></em></p>
<em>This study aimed to compare the influence of the hole diameter of the outlet of the main jet from 2.5 </em>mm<em> to 2.8 mm on the carburetor to the engine performance and fuel consumption.The test is performed with the brand gasoline motor honda tiger type GL 200 R four-stroke single cylinder. The materials studied were the main jet. Tests performed with standard conditions in without making any changes. Testing machine at the ready on a dynamometers test bed. Then do the testing phase and retrieval of data that is torque and fuel consumption. Torque (Nm) play a modified jet yield increase of 2.2% from the main jet standard. Power (kW) jet modification produces a maximum power of around 2.2% of the main jet standard. The rate of fuel consumption (mf) on the main jet modification is greater than the main jet standard. Fuel consumption (sfc) on the main jet modification will further increase the standard of the main jet. Calorific fuel (Qi) in the main jet modification is greater than the main jet standard. Jet played modifications that do not significantly change the main jet standard.</em>
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.