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DEVELOPMENT OF BASIC COMPETENCY JOBSHEET TO CUT A RECTANGULAR THREAD USING A LATHE FOR VOCATIONAL SENIOR HIGH SCHOOL Zuhda Bahtiar, fahmy; Khumaedi, M.; Syamwil, Rodia
Journal of Vocational and Career Education Vol 4, No 1 (2019): July 2019
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/jvce.v3i2.19025

Abstract

This study implemented the use of basic competency job-sheet to lathe for a rectangular thread for students of vocational high school. The numerous numbers of students who asked questions indicated that learning has been ineffective. Pretest results proved that the competency in the use of lathe with a rectangular thread did not meet KKM value. This study’s objective therefore was to understand validity, reliability, effectiveness and practicality of the jobsheet for vocational senior high school students.This study used a Research and Development method with 4Da study model approach comprising of Define, Design, Develop, and Disseminate. However, this study  only used 3D, specifically, Define, Design and Develop. The Kappa Coefficient of the VCR raw material was used to gain validity and reliability of the jobsheet content. Two group pretest-posttest designs were used to test effectiveness of the jobsheet, and students’ response to questionnaires were used to understand their  responses.The results of study indicate that validity of the jobsheet content is derived from 2 raters which indicate CVI value with a valid category. Reliability of the jobsheet content showed this was the most substantial category. The results of effectiveness given illustrates that the increasing mean of the posttest values where found effective, while that of students’ responses given to an experimental class was in the very feasible category. The conclusion of this study therefore is valid, reliable, effective and practical development and can be usable for practice learning to lathe the rectangular thread.
Dampak Kadar Hardener Dan Jenis Thinner (Nc) Terhadap Hasil Lapisan Pengecatan Pada Cat Nitrocellulose (Nc) Fahmy Zuhda Bahtiar; Fahmy Fatra; Heru Sugiantoro; Riko Diki Arwanto
AEEJ : Journal of Automotive Engineering and Vocational Education Vol 4 No 1 (2023): AEEJ : Journal of Automotive Engineering and Vocational Education
Publisher : Universitas Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/aeej.v4i1.202

Abstract

This study aims to determine the effect of hardener volume and NC thinner types (super and ND) on the coating results, such as adhesion, gloss, hardness, and gasoline resistance to nitrocellulose paints (NC). This study used 5ml, 10ml, and 15ml of hardener volume variations with super and ND thinner types. The object of this research is nitrocellulose paints. This study found that the best adhesion test was produced at 5ml, 10ml, and 15ml of hardener volumes using super and ND thinners classified as 5B or 0% (percent area removed). For the best gloss test, the hardener volume was 15ml using super thinner with an average yield of 33,3 GU (Gloss Unit). The best hardness test was produced at volumes of 5ml, 10ml, and 15ml using super and ND thinners, while the best result for gasoline resistance testing was produced at volumes of 5ml, 10ml, and 15ml using super and ND thinners. Penelitian ini bertujuan untuk mengetahui pengaruh volume hardener dan penggunaan thinner jenis NC (super dan ND) terhadap hasil coating seperti gloss, adhesi, hardness dan gasoline resistance terhadap cat NC. Penelitian ini menggunakan variasi volume hardener 5ml, 10ml dan 15ml dengan penggunaan jenis thinner super dan ND. Obyek penelitian ini adalah cat nitroselulosa merek steel gloss. Hasil pada penelitian ini didapatkan bahwa uji adhesi terbaik dihasilkan pada semua variasi volume hardener dengan menggunakan thinner super dan ND yang tergolong klasifikasi 5B atau 0%. Untuk uji kilap terbaik diperoleh pada volume hardener 15ml dengan menggunakan super tiner dengan yield rata-rata 33,3 GU (Gloss Unit). Uji kekerasan terbaik dihasilkan pada semua variasi volume menggunakan tiner super dan ND, sedangkan hasil terbaik untuk pengujian gasoline resistance dihasilkan pada semua variasi volume hardener menggunakan tiner super dan ND.
Performa motor bakar satu silinder dengan variasi oktan bahan bakar dan tekanan kompresi Bahtiar Rahmat; Mohammad Burhan Rubai Wijaya; Yuris Bahadur Wirawan; Fahmy Zuhda Bahtiar
Jurnal Teknik Mesin Indonesia Vol. 18 No. 2 (2023): Jurnal Teknik Mesin Indonesia
Publisher : Badan Kerja Sama Teknik Mesin Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.36289/jtmi.v18i2.468

Abstract

The performance of an internal combustion engine was greatly influenced by several factors, including the quality of the fuel and the compression pressure of the engine. High compression pressure, followed by the selection of the appropriate fuel octane number, would result in optimal performance. Conversely, an engine with a high compression pressure given fuel with a low octane number would produce poor performance. Unfortunately, only few users know that high compression engines require fuel with high octane numbers. The purpose of this study was to determine the difference in the power & torque output of single-cylinder combustion engine given variations in compression pressure using pertamax (RON 92) & pertamax plus (RON 95) fuel. A dynamometer test has performed to determine the difference in engine performance. The results showed that the engine with high compression pressure (11.8 kg/cm2) with RON 95 fuel produced the highest power output of 7.5 kW with the highest torque output of 9.6 Nm. While the engine with low compression pressure (10 kg/cm2) using RON 92 fuel produced the lowest power output of 4.2 kW with the lowest torque output of 3.8 Nm.
DAMPAK KADAR THINNER PU TERHADAP DAYA KILAP PADA CAT DASAR LEQUER/NITROCELLULOSE (NC SEMI BLACK GLOSS) Fahmy Zuhda Bahtiar; Moh Khoirul Bahar
Journal of Automotive Technology Vocational Education Vol. 3 No. 1 (2022): April 2022
Publisher : Pendidikan Vokasional Teknologi Otomotif, Universitas PGRI Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31316/jatve.v3i1.3064

Abstract

Cat merupakan lapisan atau film yang diaplikasikan pada permukaan suatu material yang bertujuan agar tampilan lebih indah, terlindungi dari panas dan hujan sehingga menghambat laju korosi. Pada  prosedur pengecatan banyak yang harus diperhatikan seperti membersihkan permukaan sebelum pengecatan, viskositas (cat : thinner), ketebalan cat pada proses pengecatan Solvent suatu cairan yang berfungsi untuk mempermudah pencampuran resin dan pigment pada saat pencampuran cat. untuk memperoleh daya kilap yang baik dapat dilakukan salah satunya dengan cara memvariasikan kadar thinner untuk campuran cat. Penelitian daya kilap cat dilakukan di Lab Otomotif Universitas Ivet. Hasil dari dari pengujian daya kilap tertinggi pada variasi campuran 1:1,3 dengan nilai rata-rata 79.7 GU. Hal ini dikarenakan kandungan atau senyawa nitrocellulose yang ada pada cat NC yang dicampur dengan thinner ketika menguap pada saat proses penyemprotan maka akan ikut menguap dengan kata lain  kadar nitrocellulose akan berkurang sehingga daya kilap akan meningkat. Viscositas cat juga mempengaruhi daya kilap dimana ketika viscositas cat semakin kental maka proses penyemprotan (atomisasi) akan mempengaruhi permukaan menjadi kasar. Selain hal tersebut thinner PU juga memperlambat proses pengeringan dan warna hitam yang dapat menyerap cahaya sehingga didapatkan daya kilap yang maksimal dan warna hitam yang semakin pekat. Saran untuk penelitian serupa yaitu dengan menggunakan perbandinagn thinner/solvent PU dan hardener untuk daya lekatnya dan analisis biaya proses pada material plat dan plastic (ABS/PP).
Investigating Impact of Gasket Cylinder Addition and Octane Rating on Engine Performance Bahtiar Rahmat; Mohammad Burhan Rubai Wijaya; Yuris Bahadur Wirawan; Fahmy Zuhda Bahtiar; Katiko Imamul Muttaqin
Quantum Teknika : Jurnal Teknik Mesin Terapan Vol. 6 No. 1 (2024): October
Publisher : Universitas Muhammadiyah Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.18196/jqt.v6i1.23429

Abstract

The increase in people's mobility were reflected in the growing sales of motor vehicles. This has driven automotive manufacturers to compete in creating more powerful and efficient engines. These engines were designed with high compression ratios to achieve greater efficiency. High compression ratio engine re-quired fuel with the appropriate octane number to attain opti-mal performance. It is regrettable that many users had not un-derstood that an engine with high compression had required gasoline with a high octane rating as well. This research aims to investigate the impact of different compression ratios on the output power and torque of a single-cylinder combustion en-gine using RON 92, RON 95, and RON 100 gasoline. To modify the compression ratio, various numbers of gaskets were used on the cylinder head, with 2 and 3 gaskets for each configuration. A dynamometer test was employed to measure the differences in engine performance. The research results indicate that the engine with the highest compression pressure (11 Kg/cm2) using RON 100 gasoline produced the highest power of 7.90 kW, with the highest torque of 9.60 Nm. Conversely, the engine with the lowest compression pressure (10 Kg/cm2) using RON 92 gasoline produced the lowest power and the lowest torque.
KEPEMIMPINAN DAN MANAJEMEN KEPALA SEKOLAH DALAM MENYELSAIKAN PERMASALAHAN DI SEKOLAH MENENGAH KEJURUAN AL Hafidz, Miftah; Zuhda Bahtiar, Fahmy; Burhan, Nurul
Jurnal Inovasi Pendidikan dan Teknologi Informasi (JIPTI) Vol. 5 No. 1 (2024): Jurnal Inovasi Pendidikan dan Teknologi Informasi (JIPTI)
Publisher : Information Technology Education Department

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.52060/jipti.v5i1.1943

Abstract

The principal in this context plays a key role as a leader who must be able to improve the quality of human resources, especially in the context of Vocational Education. This research involved in-depth interviews with the Principal of SMK Pembaharuan Purworejo, using a qualitative approach. SMK Pembaharuan Purworejo has several problems in facing challenges, such as declining student achievement, morality issues, and challenges in preparing students for college. To overcome these problems, the Principal has implemented several strategies in both leadership and management styles. These include evaluating previous policies, providing motivation and facilities to students and teachers for their development, as well as to increase social awareness, and deepening the material with the help of peer tutors.