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All Journal Jurnal Sylva Lestari Manajemen : Jurnal Ekonomi Almikanika
Darmawan, Ryan
Unknown Affiliation
Agriculture, Biological Sciences & Forestry Earth & Planetary Sciences Economics, Econometrics & Finance Education Energy Engineering Environmental Science Industrial & Manufacturing Engineering Materials Science & Nanotechnology

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UJI KINERJA POMPA SENTRIFUGAL PADA SISTEM ALAT UJI HEAT EXCHANGER JENIS CONCENTRIC TUBE ALIRAN SEARAH Darmawan, Ryan; Sutoyo, Edi; Al-Kindi, Hablinur
ALMIKANIKA Vol 4 No 3 (2022): Juli
Publisher : UNIVERSITAS IBN KHALDUN BOGOR

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32832/almikanika.v4i3.7270

Abstract

Heat Exchanger atau alat penukar panas adalah alat yang digunakan untuk memindahkan panas dari sistem ke sistem lain tanpa perpindahan massa dan dapat pula berfungsi untuk pemanas maupun sebagai pendingin. Penelitian ini bertujuan agar menjadikan alat uji Heat Exchanger dapat berfungsi secara optimal sehingga menghasilkan data yang sesuai. Salah satu komponen yang digunakan untuk mengalirkan fluida di dalam Heat Exchanger adalah pompa sentrifugal. Setelah dilakukan uji kinerja untuk pompa yang dipilih, pompa bekerja dengan baik dan sesuai dengan kebutuhan.  Kata Kunci : Sistem Uji, Heat Exchanger, Concentric Tube
Kajian Empiris Pengaruh Disiplin Kerja Dan Lingkungan Kerja Terhadap Kinerja Guru Di SMP Muhammadiyah 26 Jakarta Suriani, Fadiyah; Tutik, Misnya; Shabil, Nadhilla Putri; Darmawan, Ryan; Abdullah, Muhammad
Manajemen: Jurnal Ekonomi Vol. 7 No. 3 (2025): Manajemen : Jurnal Ekonomi
Publisher : Fakultas Ekonomi Universitas Simalungun

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.36985/2mjcps83

Abstract

Di era persaingan sekolah swasta yang kian ketat, kinerja guru menjadi faktor penentu keberhasilan lembaga pendidikan. Di SMP Muhammadiyah 26 Jakarta, ditemukan kesenjangan signifikan, di mana 12 dari 31 guru memiliki kinerja di bawah rata-rata, padahal idealnya seluruh guru berkontribusi maksimal terhadap pencapaian tujuan sekolah. Penelitian ini bertujuan menguji pengaruh disiplin kerja dan lingkungan kerja terhadap kinerja guru dengan pendekatan kuantitatif asosiatif menggunakan sampel jenuh seluruh guru. Hasil penelitian menunjukkan bahwa disiplin kerja dan lingkungan kerja berpengaruh signifikan terhadap kinerja guru, baik secara parsial maupun simultan. Temuan penting meliputi penerapan sanksi dan penghargaan yang adil, penguasaan materi ajar, serta kenyamanan ruang kelas yang bebas dari kebisingan. Berdasarkan hasil tersebut, disarankan agar sekolah menegakkan aturan disiplin secara adil, melakukan sosialisasi rutin, memastikan mekanisme sanksi dan penghargaan konsisten, memindahkan kelas yang sering digunakan guru dari sumber kebisingan, memasang peredam suara, serta memberikan pelatihan, workshop, bimbingan teknis, dan akses sumber belajar memadai. Langkah-langkah ini diharapkan meningkatkan kedisiplinan, motivasi, dan kinerja guru secara nyata
Enhancing Pine Resin Productivity through Sulfuric Acid–Modified ETRAT Stimulants under Operational Conditions in Pinus merkusii Stands Santosa, Gunawan; Matangaran, Juang Rata; Darmawan, Ryan; Alamsyah, Darwis; Sari, Rita Kartika
Jurnal Sylva Lestari Vol. 14 No. 2 (2026): May
Publisher : Department of Forestry, Faculty of Agriculture, University of Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jsl.v14i2.1454

Abstract

Pine resin is an important non-timber forest product in Indonesia; however, the productivity of Pinus merkusii tapping remains relatively low and has not yet met industrial demand. This study evaluated the effect of a sulfuric acid–modified ETRAT stimulant on pine resin productivity under operational tapping conditions in Perum Perhutani forests in Central Java, Indonesia. Resin tapping was conducted on 160 trees distributed across four age classes (AC III–VI) using a randomized block design with four stimulant treatments: ETRAT, ETRAT + 5% H2SO4, ETRAT + 10% H2SO4, and a control without stimulant. Resin yield was monitored over 10 consecutive tapping periods, with intervals of 3 days. Resin productivity exhibited temporal variation across tapping periods, with generally lower yields during the initial tapping periods, increasing toward the intermediate periods, and declining slightly thereafter; however, differences among tapping periods were not statistically significant. Stimulant treatment significantly affected resin productivity. The highest productivity was achieved with ETRAT + 5% H2SO4 (11.29 g/quarre/day), representing an approximately 78% increase compared to the control (6.34 g/quarre/day). The addition of 10% H2SO4 did not further improve productivity, suggesting potential physiological stress associated with excessive acidity. Productivity also differed among age-class blocks, with the highest values observed in AC V and AC VI, although these differences likely reflected combined stand-level effects, including stand density and site conditions.  These findings demonstrate that low-concentration sulfuric acid modification can enhance the operational performance of organic stimulants by improving ethylene-mediated resin flow while maintaining tree physiological tolerance. These results provide practical implications for improving pine resin productivity in tropical production forests under operational management conditions. Keywords: age class, ETRAT, pine resin productivity, stimulants, sulfuric acid
Co-Authors Alamsyah, Darwis Gunawan Santosa Hablinur Alkindi Juang Rata Matangaran Muhammad Abdullah Rita Kartika Sari Shabil, Nadhilla Putri Suriani, Fadiyah Sutoyo, Edi Tutik, Misnya