Judul: Design of an Automation System for Controlling Temperature, Water pH, Oxygen Levels and Water Change Volume in Catfish Breeding Ponds (Clarias sp.)
Abstrak: Pembibitan ikan lele diharuskan dapat melihat kebutuhan yang sesuai bagi larva ikan lele terutama pada kualitas air kolam. Tetapi pada pengaplikasianya, umumnya peyesuaian kebutuhan pada kualitas air hanya dilakukan tanpa ada perlakuan khusus, sehingga kelangsungan hidup yang didapat masih rendah. Tujuan dari penelitian ini adalah untuk membuat mesin yang dapat mengendalikan kualitas air pembibitan ikan lele, menguji kinerja mesin dan pengaruh penggunaanya. Penelitian ini menggunakan metode perumusan dan evaluasi desain dan menguji kinerja mesin yang terdiri dari beberapa tahapan, antara lain: perumusan dan evaluasi desain, pabrikasi mesin, uji fungsional, uji kinerja, dan pengaruh kinerja mesin. Hasil yang diperoleh setelah pengujian adalah kinerja mesin berpengaruh terhadap kecepatan penetasan telur, laju pertumbuhan dan kelangsungan hidup larva ikan lele. Kecepatan penetasan telur ikan lele lebih cepat 4 jam dengan menggunakan mesin. Laju pertumbahan menggunakan mesin sebesar 0,061g/ekor, sedangkan tanpa menggunakan mesin sebesar 0,053g/ekor. Kelangsungan hidup larva ikan menggunakan mesin sebesar 80,3%, sedangkan tanpa menggunakan mesin sebesar 63,1%. Kata kunci: kualitas air, kelangsungan hidup, larva ikan, pengendalian, pertumbuhan, Design of an Automation System for Controlling Temperature, Water pH, Oxygen Levels and Water Change Volume in Catfish Breeding Ponds (Clarias sp.). Supervised by DESRIAL. Catfish nurseries are required to be able to see the appropriate needs for catfish larvae, especially in pond water quality. However, in its application, generally adjustments to the needs of water quality are only carried out without any special treatment, so that the survival obtained is still low. The purpose of this research is to make a machine that can control the quality of catfish breeding water, test the performance of the machine and the effect of its use. This study used the method of formulating and evaluating the design and testing the performance of the machine which consisted of several stages, including: formulating and evaluating the design, manufacturing the machine, functional testing, performance testing, and the influence of the machine performance. The results obtained after testing were the performance of the machine affecting the speed of hatching eggs, the growth rate and survival of catfish larvae. The speed of hatching catfish eggs is 4 hours faster using a machine. The growth rate using a machine is 0.061g/head, while without using a machine it is 0.053g/head. The survival of fish larvae using machine was 80.3%, while without using machine was 63.1%.
Keyword: Rancang Bangun, Kualitas Air, Pembibitan Lele, Kontrol Otomatis, water quality, survival, fish larvae, control, growth

Judul: Analisis Penggunaan Semi-Automatic Feeder terhadap Kinerja Usaha Budidaya Ikan Lele (Clarias sp.) di CV Vatra Mandiri Agro, Depok
Abstrak: Tren peningkatan produksi ikan lele diiringi dengan peningkatan kebutuhan dan harga pakan. Hal ini akan berakibat pada tingginya biaya produksi ikan lele. Salah satu solusi penghematan dapat dilakukan dengan penekanan biaya tenaga kerja dengan penggunaan semi-automatic feeder. Penelitian ini bertujuan menganalisis produktivitas tenaga kerja pada metode pemberian pakan dengan penggunaan semi-automatic feeder dan manual feeding dalam usaha pembesaran ikan lele. Perlakuan pada penelitian ini, yaitu kolam dengan manual feeding (A) dan kolam dengan semi-automatic feeder (B), masing-masing dengan 3 ulangan. Ikan lele dengan bobot 3,4 ± 0,82 g dan panjang 7,8 ± 0,65 cm dipelihara dalam kolam berukuran 8 m x 12 m x 0,65 m dengan padat tebar 481 ekor/m3. Selama 83 hari pemeliharaan, ikan diberi pakan tiga kali sehari. Mesin feeder menyemprotkan pakan dengan kecepatan 16 g/detik. Data pertumbuhan diambil sebanyak lima kali dalam 83 hari masa pembesaran. Hasil penelitian menunjukkan bahwa parameter tingkat kelangsungan hidup (TKH), laju pertumbuhan mutlak panjang (LPMP), dan laju pertumbuhan mutlak bobot (LPMB) berpengaruh nyata, sedangkan jumlah konsumsi pakan (JKP), rasio konversi pakan (RKP), dan total panen tidak menunjukkan perbedaan pada budidaya ikan lele. Berdasarkan indikator produktivitas tenaga kerja menunjukkan usaha pembesaran ikan lele dengan semiautomatic feeder memiliki produktivitas yang lebih tinggi yang lebih tinggi., The increasing trend in catfish production aligns with an increase in feed demand and price. This contributes to the higher overall production cost. One cost- saving solution is by suppressing the labour cost through the use of semi-automatic feeder. This research aims to analyse labour productivity in the method of feeding using semi-automatic feeders and manual feeding in the catfish farming business. The treatments in this research were ponds with manual feeding (A) and ponds with semi-automatic feeders (B), each with 3 replicates. Catfish at initial weight of 3.4 ± 0.82 g and a length of 7.8 ± 0.65 cm were reared in ponds measuring 8 m x 12 m x 0.65 m with a stocking density of 481 fish/m3. During the 83 days of cultivation, the fish were fed three times a day. The automatic feeder dispensed feed at a rate of 16 g/second. Growth data were collected five times during the 83-day growth period. The research results show that survival rate (TKH), absolute growth rate in length (LPMP), and absolute growth rate in weight (LPMB) had a significant effect, while feed consumption (JKP), feed conversion ratio (RKP), and total harvest did not show any differences in catfish farming. Based on labor productivity parameters, catfish farming with semi-automatic feeders showed higher productivity.
Keyword: business, catfish, culture, semi-automatic feeder

Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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