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ANALYTICAL CALCULATION FOR LAMINAR AIR FLOW MOMENTUM TRANSPORT IN UNDERGROUND MINE TUNNEL USING NEWTONIAN EQUATIONS OF MOTION Algifari, Arif; Adrian, Adrian
ORBITA: Jurnal Pendidikan dan Ilmu Fisika Vol 9, No 2 (2023): November
Publisher : Universitas Muhammadiyah Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31764/orbita.v9i2.17053

Abstract

ABSTRAKDalam kasus tertentu terdapat terowongan percabangan tambang bawah tanah yang tidak teralirkan udara secara mekanis tetapi udara tetap mengalir secara alami teridentifikasi beraliran laminar. Studi ini memodelkan perpindahan momentum aliran laminar udara terowongan dengan dimensi rectangular atau Cartesian untuk memvisualisasikan profil distribusi kecepatan linier fluida dan profil tegangan geser fluida. Metode pemodelan menggunakan perhitungan analitik matematika dari persamaan gerak aliran fluida Newtonian untuk rejim laminar Navier-Stokes. Beberapa data yang dikumpulkan adalah dimensi terowongan, kecepatan linier udara, dan temperatur. Beberapa sifat fisik udara dikutip dari literatur. Hasil pengukuran kecepatan udara rata-rata diinputkan ke dalam model empiris untuk mendapatkan profil koordinat dua dimensi (x,z) untuk distribusi tegangan geser dan kecepatan udara yang mendekati keadaan sebenarnya untuk aliran laminar pada dimensi Cartesian. Hasil penelitian didapatkan pressure drop aliran sebesar 2,2 x 10-5 Pa, aliran mengandalkan perpindahan molekular bukan perpindahan secara konveksi paksa karena dilihat dari profil sebaran tegangan geser yang terlalu kecil dan laju alir sebesar 0,32 m3/s tidak memenuhi fungsi ventilasi tambang bawah. Kata kunci: perpindahan momentum; aliran laminar; fluida newtonian; ventilasi tambang. ABSTRACTIn certain case there is a mine tunnel branch that is not mechanically ventilated but air still flow naturally identified as laminar flow. This study modelled the momentum transport of the tunnel air laminar flow with rectangular or Cartesian dimensions to visualize the linear velocity distribution profile of the fluid and the fluid shear stress profile. The modelling method uses analytical mathematical calculations of the Newtonian fluid flow equations of motion for the laminar regime of Navier-Stokes. Some of the data collected are tunnel dimensions, air linear velocity, and temperature. Some physical properties of air are cited from literature. The results of the average air velocity measurement are input into the empirical model to obtain two-dimensional coordinate profiles (x,z) for the shear stress distribution and air velocity that are close to the actual situation for laminar flow in the Cartesian dimension. The results of the study obtained a pressure drop of the flow was 2,2 x 10-5 Pa, the flow using molecular transport instead of forced convection transport because seen from the shear stress distribution profile was too small and the flow rate was 0,32 m3/s did not fulfill the underground mine ventilation function. Keywords: momentum transport; laminar flow; newtonian fluid; mine ventilation.
Effectiveness of the Prof. Tito Storybook in Enhancing Student Learning in Indonesian Language and Natural Science for Fifth Grade Elementary School Students Azima, Nana Fauzana; Iraqi, Hana Shilfia; Algifari, Arif; Zahra, Lailatul; Putri, Ellsy Rahmadani
Mimbar Sekolah Dasar Vol 11, No 2 (2024)
Publisher : Universitas Pendidikan Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.53400/mimbar-sd.v11i2.66318

Abstract

This research addresses the issue of unsuitable children's storybooks influencing elementary students' thinking patterns by mirroring adult behaviors, prompting the development of the modern children's storybook "Prof. Tito: Electric Bicycle Edition" to enhance literacy and science technology education. The specific aim is to evaluate the effectiveness of character-based and science technology-focused storybooks in improving Indonesian and natural sciences learning among fifth-grade students. "Prof. Tito, Electric Bike Edition" explores values like cooperation, mutual assistance, and knowledge of electric bicycles, offering a moral foundation for young readers. The study highlights the storybook's role in fostering empathy and focus, while educating readers about electric bicycles in the context of Indonesian language and science. Through student evaluations, the book's efficacy was tested, showing significant learning improvements. The findings reveal a 13.49% and 12.55% increase in learning outcomes, classifying the storybook as moderately effective in enhancing learning. Overall, the research concludes that the storybook significantly contributes to improving student learning outcomes, representing an original contribution to the field.
Y Zeolite-Based Catalyst for Palm Oil Cracking to Produce Gasoline Algifari, Arif; Makertihartha, I. G. B. N.; Subagjo, Subagjo; Prabowo, Heri
Bulletin of Chemical Reaction Engineering & Catalysis 2025: BCREC Volume 20 Issue 1 Year 2025 (April 2025)
Publisher : Masyarakat Katalis Indonesia - Indonesian Catalyst Society (MKICS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.9767/bcrec.20267

Abstract

The increasing demand for oil fuel and the decline of crude oil reserves highlight the need for alternative energy sources. Palm oil, as a renewable resource, has potential for biofuel production through catalytic cracking. This study aims to develop and evaluate modified zeolite-based catalysts, particularly ZSM-5/HY, to produce palm oil-derived gasoline that meets European fuel standards. The research involved catalyst preparation, modification with ZSM-5 and phosphorus, and activity testing in a fixed-bed reactor. Gasoline yield and catalyst performance were analyzed using gas chromatography. The results showed nearly 100% conversion of palm oil under optimal conditions, with gasoline yield meeting European standard. The addition of ZSM-5 improved conversion and RON, while phosphorus modification reduced catalyst acidity, affecting yield and coke formation. This study concludes that modifying zeolite catalysts with ZSM-5 and phosphorus enables efficient palm oil-derived gasoline production with high RON and reduced aromatic content, contributing to sustainable energy solutions. Copyright © 2025 by Authors, Published by BCREC Publishing Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).