Judul: Design and Construction of Ecofriendly Line Hauler for Collapsible Trap Using 5 GT Fishing Boat
Abstrak: The blue swimming crab (rajungan) fishing industry in the coastal area of Karawang has been employing a longline system to capture crabs using traditional crab traps. To expedite and simplify the process of hauling the crab traps onto the fishing boat, fishermen have been using a line hauler, even though without considering the substantial load it exerts on the equipment. Furthermore, the existing line hauler relies on fossil fuels for operation, which is not environmentally sustainable. It also generates carbon dioxides as well as noise pollution during operation. This research aims to design and construct an eco-friendly line hauler that does not rely on fossil fuels and operates with lower noise levels. The design and construction of the line hauler prototype were conducted in several stages. Initially, hydrodynamic force estimations were made for the crab trap assembly during the hauling process. Subsequently, a prototype was designed to suit the operational environment through appropriate design selection. This was followed by functional and performance testing in a real-world environment. The final stage involved assessing positive responses toward fishers and estimating the cost of operating the prototype. The research was carried out from June 2022 to September 2023. The research methodology involved design, construction, and technical function and performance testing. Primary data collection was conducted in the form of measurement results and observations from the initial stages to the functional and performance tests. The data was processed using software and mathematical calculations, presented in tabular form. Data analysis was conducted through quantitative and qualitative comparative analysis of the existing equipment and the prototype. The research findings demonstrate that the prototype of the line hauler surpasses the existing equipment. The prototype uses electric propulsion, making it more environmentally friendly by eliminating the use of fossil fuels and operating quietly below the threshold values especially in fishing area of fishermen. The prototype when subjected to functional testing, received positive responses from the fishers operating it, and also the operationl cost significantly reduced, reaching a cost reduction of 63%., Bubu rajungan yang dioperasikan dengan sistem longline, membutuhkan alat bantu penangkapan untuk memudahkan dan mempercepat waktu penarikan bubu rajungan ke atas kapal. Nelayan buburajungan di pesisir Karawang telah menggunakan alat bantu penarik tali utama namun belum mempertimbangkan besar beban yang ditanggung oleh alat bantu serta masih menggunakan mesin penggerak yang kurang ramah lingkungan Ramah lingkungan yang dimaksud adalah alat bantu eksisting masih menggunakan bahan bakar fosil yang menghasilkan gas buang CO₂ dan kebisingan saat operasional. Tujuan dari penelitian ini adalah untuk membuat alat penarik bubu rajungan yang lebih ramah lingkungan yaitu tidak menggunakan penggerak berbahan bakar fosil dengan tingkat kebisingan dibawah Nilai Ambang Batas (NAB) yang berlaku. Dalam merancang bangun alat penarik tali bubu rajungan prototipe yang dibuat dilakukan dengan beberapa tahapan. Tahap awal dimulai dengan melakukan perhitungan estimasi gaya hidrodinamika pada rangakain bubu rajungan saat proses penarikan (hauling). Selanjutnya tahap perancangan prototipe yang sesuai dengan lingkungan operasional melalui pemilihan desain yang sesuai. Kemudian dilanjutkan dengan pengujian fungsi dan kinerja pada lingkungan yang sebenarnya. Tahap akhir adalah menggali respon positif terhadap rancang bangun kepada nelayan dan menghitung estimasi biaya
Keyword: crab traps, Line hauler, Ecofriendly

Judul: Folding Trap Door Construction Modification for Blue  Swimming Crab (Portunus sp.)
Abstrak: Produksi rajungan di PPN Karangantu cenderung menurun. Hal ini menunjukkan bahwa alat tangkap yang digunakan yakni bubu belum efektif, sehingga diperlukan modifikasi. Modifikasi yang dilakukan yaitu menghilangkan bentuk funnel dan diganti dengan pintu satu arah pada mulut bubu, sehingga tujuan dari penelitian ini adalah membandingkan respons dan tingkah laku rajungan terhadap bubu kontrol dan bubu modifikasi, terdiri dari pola pergerakan mendekati bubu serta waktu yang dibutuhkan untuk menemukan pintu bubu dan memasuki bubu. Metode yang digunakan pada penelitian ini adalah percobaan laboratorium. Hasil penelitian yang didapatkan yaitu pola pergerakan rajungan pada bubu modifikasi umumnya melalui bagian tengah pintu sedangkan pada bubu kontrol melalui bagian sisi funnel. Pola pergerakan memengaruhi waktu yang dibutuhkan rajungan untuk menemukan pintu dan memasuki bubu. Perbedaan waktu yang dibutuhkan rajungan dalam menemukan pintu bubu kontrol dan modifikasi menunjukkan perbedaan yang signifikan, namun waktu rajungan memasuki bubu tidak menunjukkan adanya perbedaan yang signifikan antara kedua jenis bubu, The production of blue swimming crab in Karangantu Archipelago Fishing Port tends to decrease. This indicates that the fishing gear used, namely the trap, is not effective, thus requiring modification. The modification involves removing the funnel-shaped entrance and replacing it with a one-way door at the mouth of the trap. The purpose of this study is to compare the responses and behavior of crabs towards the control trap and the modified trap, specifically examining their approach patterns towards the trap and the time taken to find and enter the trap. The method used for this research is a laboratory experiment. The results show that the movement pattern of crabs towards the modified trap mostly occurs through the center of the door, while for the control trap, it occurs through the sides of the funnel. The movement pattern affects the time taken by crabs to find the trap's door and enter it. There’s a significant difference in the time taken by crabs to find the door between the control and modified traps. However, there’s no significant difference in the time taken by crabs to enter the traps between the two types.
Keyword: funnel, pintu satu arah, Portunus sp., one-way door

Judul: Penentuan Nilai Eigen dan Vektor Eigen dari Matriks Tridiagonal 2-Toeplitz dengan Pendekatan Polinomial Chebyshev
Abstrak: The eigenvalues and eigenvectors of a matrix can be determined by finding its characteristic polynomials. The characteristic polynomials of a tridiagonal 2-Toeplitz matrix is shown to be closely connected to polynomials which satisfy the Chebyshev recurrence relationship. If the order of the matrix is odd, then the eigenvalues are found explicitly in terms of the Chebyshev zeros and the eigenvectors are found in terms of the polynomials satisfying the recurrence relationship. For even ordered matrices, the situation is more complicated. The problem in these cases is that although the Chebyshev recurrence formula is still applied, its initial values are not generating Chebyshev polynomials
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