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"Sebagian besar energi terbuang ke lingkungan dalam bentuk panas limbah dari berbagai industri manufaktur. Dengan meningkatnya harga bahan bakar fosil dan perhatian terhadap dampak lingkungan yang terus berkembang, pemanfaatan kembali panas limbah menjadi semakin penting untuk efisiensi energi. Pemulihan panas limbah pada suhu rendah sangat menantang, karena siklus Rankine konvensional tidak mampu mengonversinya menjadi listrik akibat keterbatasan sifat fluida kerja. Sebaliknya, Siklus Rankine Organik (ORC) diakui sebagai teknologi yang menjanjikan untuk mengonversi panas bersuhu rendah menjadi listrik, sehingga sangat cocok untuk pemulihan panas limbah industri. Penelitian ini bertujuan untuk menganalisis kinerja sistem ORC yang menggunakan R245fa sebagai fluida kerja, khususnya untuk sumber panas bersuhu di bawah 90°C. Pengaturan eksperimen melibatkan penggunaan scroll expander dan recuperator tipe double-tube. Hasil penelitian menunjukkan bahwa efisiensi termal net tertinggi pada setting temperatur 80°C dan 85°C berturut-turut adalah 3,1% dan 3,9%. Efisiensi termal net yang rendah disebabkan oleh dua faktor utama, yaitu kombinasi antara laju alir fluida kerja dan temperatur sumber panas yang terlalu rendah, serta penggunaan pompa utama yang terlalu besar. Temuan ini menekankan pentingnya mengoptimalkan komponen sistem dan parameter operasional untuk meningkatkan kinerja ORC.

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A significant amount of energy is being released to the environment in the form of waste heat from many manufacturing industries. With rising fossil fuel prices and growing environmental concerns, recovering this waste heat has become increasingly important for efficient energy utilization. Waste heat recovery is particularly challenging at low temperatures, as conventional Rankine cycles are unable to convert it into electricity due to the limitations of working fluid properties. In contrast, the Organic Rankine Cycle (ORC) is widely recognized as a promising technology for converting low-temperature heat into electricity, making it highly suitable for industrial waste heat recovery. This study aims to analyze the performance of an ORC system using R245fa as the working fluid, specifically for heat source temperatures below 90°C. The experimental setup includes a scroll expander and a double-tube recuperator. The results showed that the highest net thermal efficiency at temperature settings of 80°C and 85°C were 3.1% and 3.9%, respectively. The low net thermal efficiency is attributed to two primary factors: the combination of low working fluid flow rates and heat source temperatures, as well as the use of an oversized main pump. These findings highlight the importance of optimizing system components and operational parameters to enhance ORC performance."

"This study investigated the optimum value of Archimedes Screw Turbine (AST) performance by taking into account blades number. This paper also addressed the design approach based on a fixed incline angle of 30°, where this paper also addressed the design approach. Variations of the single and double blades were experimentally carried out concerning the turbine power output, torque, and rotation speed. This study's aim was related to the optimum power output between two blade variations, while the manufacturing and design steps were addressed as well. In the design process, the obtained blade length dimension was 0.180 m and 0.269 m for the single and double blades. Furthermore, the overall turbine's length was 1.7m, and the inner and outer of the turbine's radius were 0.069m and 0.128m. Meanwhile, the manufacturing process began with turbine modeling, plate cutting, plate withdrawal (thread formation), welding, and attained finishing process. Based on the experimental result, a double blade turbine generated turbine power by 48.8W at an average rotational speed of 115.3 rpm. Moreover, a single blade turbine produced 37.5W with turbine power averaging a rotational speed of 109.8 rpm. It was obtained that the values of turbine efficiency were 42% and 38% for double and single turbine types, respectively. Based on this finding, it can be suggested that a double blade was more efficient than a single one. This study is beneficial for the design consideration of the AST system."

"Penelitian ini didasarkan pada data yang diperoleh dari institusi Pemerintah, lembaga kredit, Biro Pusat Statistik (BPS) dan lembar pertanyaan yang berhubungan dengan nelayan kecil di wilayah Surabaya. Penelitian ini bertujuan untuk mengetahui faktor-faktor yang mempengaruhi rendahnya pendapatan nelayan serta mengetahui peran pemerintah dalam rangka meningkatkan pendapatan nelayan sehingga profesi ini tetap eksis di Surabaya. Untuk mencapai tujuan tersebut, data penelitian yang digunakan adalah mengumpulkan informasi melalui lembar pertanyaan (questioner) dan analisa berdasarkan teori yang relevan. Dari penelitian yang dilakukan, hasil yang didapatkan adalah bahwa ada beberapa faktor yang menjadi penyebab rendahnya pendapatan nelayan sementara intervensi pemerintah seringkali tidak sesuai dengan permasalahan yang dihadapi oleh nelayan tersebut. Bisa dikatakan bahwa campur tangan pemerintah tidak memberikan pengaruh yang signifikan terhadap pendapatan nelayan. Hal ini dikarenakan untuk menentukan faktor rendahnya pendapatan nelayan juga tidak mudah. Nelayan sering mengalami ketidakpastian pendapatan karena faktor luar seperti iklim, cuaca, bencana alam, penyakit ikan dan ketergantungan nelayan terhadap institusi keuangan yang menerapkan bunga tinggi, anggota keluarga yang besar, daya tawar nelayan yang rendah. Sementara faktor dari dalam adalah rendahnya ketrampilan dan pendidikan. Hal tersebut menjadikan nelayan sangat sulit untuk keluar dari permasalahannya. Sehingga bantuan serta perhatian pemerintah dan organisasi lain diharapkan ikut membantu melepaskan nelayan dari kemiskinan. Kemudahan akses ke aset-aset pemerintah adalah penting untuk membantu nelayan untuk lebih berdaya dan mencoba meningkatkan pendapatannya. Aset memiliki peran yang cukup penting karena bisa meningkatkan produktivitas yang selanjutnya bisa membantu meningkatkan pendapatan mereka. Dalam penelitian ini pemerintah turut campur dalam pemberian kemudahan akses ke berapa aset untuk dimanfaatkan oleh nelayan. Tujuan lainnya dengan adanya aset tersebut, nelayan bisa keluar dari zona kemiskinan.agar tepat sasaran, pemerintah harus mengetahui permasalahn yang sebenarnya yang dihadapi oleh nelayan tersebut.Hasil penelitian menyimpulkan bahwa kemampuan nelayan mempertahankan dan mengatur harga ikan di pasaran menjadi penyebab utama rendahnya pendapatan nelayan disamping penyebab lain yang turut berperan dalam rendahnya pendapatan nelayan. Sehingga penelitian ini memberikan rekomendasi untuk melakukan survey untuk mendapatkan pemahaman yang spesifik tentang penyebab utama rendahnya pendapatan nelayan. Penggabungan metode kualitatif melaui survey dan wawancara langsung adalah metode yang lebih baik untuk mendapatkan gambaran yang lebih tepat.

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This study based on the data were collected from the Government institution, credit institution, statistical bureau and question sheet from the small scale fishing community in Surabaya, this study examines the determinants factors of low level income of the fisher and investigate whether intervention of government help poor fisher increase their income and come with their problem in order to sustain their livelihood. For gain this purpose, this study use data collected and information through questoion sheet and analyzed using relevant theories. Result shows that several factor determined the low level income of fishers and the government interventions are not matching with the fishers problem. On the another words, the intervention could not help fisher to generate their income significantly. The determinant factors of low level income fisher is very complicated. Poor fishers are not only face problem from the outside factors such as natural disaster, climate change, fish diseases, dependency on high interest private debt,large family member, weak bargaining power but also from the inside such as low level of skill and education.

Escaping from all the problems is difficult for the poor fishers, attention from the government and another organization is needed by them to escape from the poverty and sustain their livelihood. Easier of getting access to assets from the community organization or government is important for the fisher to try improve their ability and open chances for them to empower themselves. Assets is the main important thing especially for the poor fisher because commonly they lack n accessing asset. Assets also the most important things in sustainable livelihood. In this study, government gave support on several assets which are aimed to help poor fisher increasing their income by increasing productivity and opening opportunity to diversify their livelihood. Some of the interventions provided by government can lead them to increase their income, in another side, the interventions also give opportunity to pull them in to deeper poverty. To get better and positive impact on those interventions, governent should have more understanding on the determinant factors which are caused fisher’s problem.

Ths study argue that ability to set the fish price and get better bargaining power in the market seem the strongest reason of the fisher’s low level income problems. Even though many factors also take part on that situation. Finally, this study suggest to do survey for get better understanding on fisher main problems, so combining qualitative method through survey and in depth interview may will give more precise figure of fisher conditions.

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"Introduction to scientific inquiry, experimental design in psychology, ethics of experimental research, controls, and analysis of experiments."