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Efisiensi Energi dan Kelayakan Ekonomi Penerapan Varible Speed Drive Pada Sistem Pompa Distribusi Process Water Yolnasdi Yolnasdi; Triana Ramdha; Ermawati Ermawati; Kevin Kevin; Chrismondari Chrismondari
SAINSTEK Vol. 14 No. 1 (2026)
Publisher : Sekolah Tinggi Teknologi Pekanbaru

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.35583/js.v14i1.463

Abstract

Sistem distribusi process water pada industri umumnya menggunakan motor induksi berdaya besar yang beroperasi secara kontinu sehingga berkontribusi signifikan terhadap konsumsi energi listrik. Pengendalian debit menggunakan metode throttling valve pada sistem Direct On Line (DOL) sering menimbulkan inefisiensi energi akibat motor tetap beroperasi pada kecepatan nominal meskipun kebutuhan debit berkurang. Penelitian ini bertujuan untuk menganalisis efisiensi energi dan kelayakan ekonomi penerapan Variable Speed Drive (VSD) pada motor pompa sentrifugal berkapasitas 500 kW di PT Riau Andalan Pulp and Paper. Metode penelitian menggunakan pendekatan deskriptif kuantitatif dan komparatif berdasarkan data operasional aktual yang diperoleh dari Human Machine Interface (HMI) dan Electronic Tripping Unit (ETU) selama 14 hari pengamatan. Analisis ekonomi dilakukan menggunakan metode Simple Payback Period (SPP). Hasil penelitian menunjukkan bahwa penggunaan VSD mampu menurunkan konsumsi daya secara signifikan dibandingkan metode DOL dengan throttling valve. Pada kondisi operasi setara 50%, konsumsi daya sistem DOL tercatat sebesar 318 kW, sedangkan sistem VSD hanya sebesar 32 kW. Implementasi VSD menghasilkan penghematan energi rata-rata sebesar 4.042,19 kWh per hari atau setara 1.475.399,35 kWh per tahun. Penghematan energi tersebut memberikan reduksi biaya operasional sebesar Rp1.645.070.275,25 per tahun. Dengan nilai investasi sebesar Rp5.000.000.000, sistem memiliki periode pengembalian modal selama 3,039 tahun. Hasil penelitian menunjukkan bahwa penerapan Variable Speed Drive layak diterapkan sebagai solusi konservasi energi dan peningkatan efisiensi operasional pada sistem pompa distribusi process water industri.
The Influence of Self-Directed Learning on Teacher Certification Success: Logistic Regression Analysis among Indonesian English Language Teachers Triana Ramdha; Mirfaturiqa
Jurnal Studi Guru dan Pembelajaran Vol. 9 No. 2 (2026): May - August 2026
Publisher : Universitas Cokroaminoto Palopo

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30605/jsgp.9.2.2026.9611

Abstract

This study investigated whether Self-Directed Learning (SDL), as viewed through the lens of Self-Determination Theory (SDT), predicts the chance of teacher professional certification (Pendidikan Profesi Guru, PPG) achievement among Indonesian English language teachers. Using a quantitative cross-sectional methodology, connected survey and certification records for 46 instructors selected purposively from Riau and nearby areas were examined using binary logistic regression. SDL was measured with a 15-item, three-dimensional instrument spanning autonomy, competence, and relatedness, which demonstrated excellent internal consistency in the current sample (α = .93). A confirmatory model tested total SDL score alongside teaching experience, while an exploratory model decomposed SDL into its three subscales. Total SDL score significantly predicted certification success after adjusting for teaching experience (OR = 1.12, 95% CI [1.01, 1.24]), with good model discrimination (AUC = .83) and adequate calibration (Hosmer-Lemeshow p = .49); teaching experience was the strongest single predictor (OR = 3.15). At the subscale level, only autonomy remained an independent, significant predictor (OR = 1.61, p = .036), while competence and relatedness did not reach significance once their shared variance was accounted for. These findings indicate that autonomy-supportive, self-initiated professional learning is the SDL dimension most worth prioritizing in PPG preparation and mentoring, while pointing to the need for larger, more complete datasets to confirm which dimensions matter most. The study contributes quantitative, probability-based evidence to a body of SDL-professional development literature that has so far relied largely on qualitative and continuous-outcome designs.