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All Journal INVOTEK: Jurnal Inovasi Vokasional dan Teknologi Justek : Jurnal Sains Dan Teknologi GeoEco
Arif Algifari
Universitas Negeri Padang
Automotive Engineering Civil Engineering, Building, Construction & Architecture Computer Science & IT Control & Systems Engineering Earth & Planetary Sciences Education Electrical & Electronics Engineering Energy Engineering Environmental Science Industrial & Manufacturing Engineering Mathematics Social Sciences Transportation

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Implementation of Project Based Learning for Cognitive and Psychomotor Students in the Basic of Workshop Technology Course Welding Sub-competency in the Automotive Engineering Study Program Rahma Doni; Arif Algifari; Muhammad Irvan
invotek Vol 22 No 3 (2022): INVOTEK: Jurnal Inovasi Vokasional dan Teknologi
Publisher : Universitas Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/invotek.v22i3.1073

Abstract

The higher education curriculum adopts project-based learning (PjBL) method that emphasizes the provision of knowledge with the problem solving in an organized work project within study group. This is such a solution for the problems of current conventional learning method implementation that made low enthusiasm and slow understanding student especially for Automotive Engineering student in having welding practice in The Basic Workshop Technology Course. By using experimental method in this research to compare conventional learning and PjBL method toward twenty Automotive Engineering students to evaluate cognitive and psychomotor aspect. On the steps, the lecturer starts with provides theoretical enrichment and end with welding practice. To find out the effect of implementing this project-based learning, lecturer divides the class in two study groups by differentiating learning methods, namely the group with conventional learning and the group with PjBL learning. Comparison is made between conventional learning and PjBL learning with projects processed by statistical interpretation. The results of the study showed that there was a significant effect on the results of the psychomotor evaluation of students, but not too significant for the cognitive evaluation results. Based on this research, there is a prove that PjBL is good enough to increase student’s abilities in welding practice as psychomotor representation increment.
Studi Review: Evaluasi Batubara Formasi Sawahlunto sebagai Batuan Induk Hidrokarbon Arif Algifari; Syari Rahma Yanti; Fitri Nauli
Justek : Jurnal Sains dan Teknologi Vol 6, No 3 (2023): September
Publisher : Unversitas Muhammadiyah Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31764/justek.v6i3.16686

Abstract

Abstract: Hydrocarbons are still source of energies that people are interested in. This energy source does not only come from source rock of  formations and reservoirs of oil and natural gas, hydrocarbon sources can also be found in the organic depositional environment of coal formations. The Ombilin Basin in West Sumatra stores coal deposits that were formed during the Tertiary period in a non-marine environment, precisely in the Sawahlunto formation. This study aims to identify the potential of light hydrocarbons from coal as a source rock. The identification method was carried out by studying the geochemical and petrological characteristics of coal based on the literature study approach and geological survey of the basin to obtain information that the organic component of the coal of the Sawahlunto formation is dominated by vitrinite maceral. The relationship between maceral and the hydrogen/carbon ratio is plotted on a Van Krevelen diagram to determine the hydrocarbon recovery. The genesis of this coal deposit comes from plants that have the potential to produce methane coal gas or coal bed methane because it has the characteristics of bituminous class coal with high volatile content with an empirical hydrogen/carbon ratio kerogen III type of 0.65-0.7, tends to occur condensation of hydrocarbons releasing aliphatic bonds while aromatization continues increase.Abstrak: Hidrokarbon masih menjadi sumber energi yang diminati masyarakat. Sumber energi ini tidak hanya berasal dari formasi batuan induk dan reservoir minyak bumi serta gas alam, sumber hidrokarbon juga dapat ditemukan pada lingkungan pengendapan organik formasi batubara. Cekungan Ombilin di Sumatera Barat menyimpan endapan batubara yang terbentuk selama periode Tersier pada lingkungan non laut tepatnya pada formasi Sawahlunto. Penelitian ini bertujuan untuk mengidentifikasi potensi hidrokarbon ringan dari batubara sebagai batuan induk. Metode indentifikasi dilakukan dengan mempelajari karakteristik geokimia dan petrologi batubara berdasarkan metode pendekatan studi literatur dan survey geologi cekungan hingga diperoleh informasi bahwa komponen organik batubara formasi Sawahlunto didominasi oleh maseral vitrinit. Hubungan antara maseral terhadap rasio hidrogen/karbon diplot pada diagram Van Krevelen untuk menentukan perolehan hidrokarbon. Genesis endapan batubara ini berasal dari tumbuh-tumbuhan yang berpotensi menghasilkan gas metana batubara atau coal bed methane karena memiliki karakteristik batubara kelas bituminus volatil tinggi tipe kerogen III dengan rasio hidrogen/karbon empiris 0,65-0,7 cendrung terjadi kondensasi hidrokarbon melepaskan ikatan alifatik sedangkan aromatisasi terus meningkat.
TOPOGRAPHIC MAPPING, TEMPERATURE DISTRIBUTION, AND pH OF HOT SPRINGS IN PADANG GANTING, TANAH DATAR, WEST SUMATRA: A PRELIMINARY STUDY Arif Algifari; Wahyudi Ardiansyah; Ilham Gilang Ramadhan
GeoEco Vol 10, No 2 (2024): GeoEco July 2024
Publisher : Universitas Sebelas Maret (UNS)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20961/ge.v10i2.86131

Abstract

This preliminary study explores the hot springs in Padang Ganting, Tanah Datar, West Sumatra, at coordinates 00°34'8.404" S - 100°42'45.716" E and 0°31'26.431" S - 100°45'27.598" E. The research was conducted using geological and geochemical methods in the geothermal field. The collected data includes coordinates of the area, temperature, and pH of the hot springs. The results show a pH distribution ranges from 6 to 7 at several points of the hot springs, with slightly brackish characteristics, and the temperature of the hot springs ranges from 41°C to 51°C. The immature meteoric hot springs originate from the granite formation, indicating the possibility of magma intrusion to the surface, possibly caused by the oroclinal shear segment in the upper part of the Ombilin basin. This study provides a basis for further geological investigations into the geothermal potential and prospects for further development in the geothermal field, contributing to understanding the geological processes in the region.
Investigation of Rare Earth Elements from Coal-Derived Minerals of Sawahlunto Formation and Leaching Behavior Under NaOH and HCl Washing Treatment Arif Algifari; Fitri Nauli; Andri Van Deni; Siti Aisyah; Dwi Wulan Syakira
Justek : Jurnal Sains dan Teknologi Vol 8, No 4 (2025): December
Publisher : Unversitas Muhammadiyah Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31764/justek.v8i4.33908

Abstract

The growing demand for rare earth elements (REE) in modern technological applications has encouraged the exploration of alternative REE sources, including minerals associated with coal. This study aims to evaluate the potential of minerals in the Sawahlunto Formation coal from the Ombilin Basin as a secondary REE source through an alkaline leaching approach. Coal samples from the Sawahlunto Formation were subjected to alkaline leaching using sodium hydroxide solutions of 200–600 g/L at temperatures of 38–78 °C for 0.5–1.5 hours, followed by an acid-washing stage using 14% hydrochloric acid. X-ray fluorescence analysis identified yttrium, lanthanum, and cesium, with a total initial REE content of approximately 181 ppm. The leaching results show that under optimal conditions 400 g/L NaOH, 78 °C, and a particle size of 60/70 mesh, the residual REE content decreased to 2 ppm, indicating effective dissolution of REE-bearing mineral components. Subsequent acid washing further enhanced REE recovery by removing remaining soluble phases. These results demonstrate that coal from the Sawahlunto Formation possesses promising characteristics as a secondary REE source.
Analysis of Ground Movement Using Geographic Information System Method in the Area of Kolok Mudik Village, Barangin District, Sawahlunto City Syari Rahma Yanti; Fairus Atika Redanto Putri; Aulia Hidayat Burhamidar; Fitri Nauli; Arif Algifari; Herdian Pratama
Justek : Jurnal Sains dan Teknologi Vol 8, No 1 (2025): Maret
Publisher : Unversitas Muhammadiyah Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31764/justek.v8i1.29250

Abstract

Abstract:  Kolok Mudik Village area has topography that varies between flat, undulating and hilly with a height above sea level.With this very varied height, it has quite steep slopes and has the potential for landslides. Apart from that, coal mining activities around the village make the land unstable. This research aims to map areas that are prone to land movement in Kolok Mudik village. The method used in this research is using a map overlay using the GeographicIinformation System (GIS) application. The parameters used in this model are soil type, rock type, land slope, geological formation, land use, and rainfall. In the mapping process, each parameter has a classification score which is multiplied by the weight of each parameter. Based on the results of data processing, the results show that the vulnerability of land movement in Kolok Mudik Village is in the medium to high categoryAbstrak: Wilayah Desa Kolok Mudik memiliki topografi yang bervariasi antara datar, bergelombang dan berbukit dengan ketinggian di atas permukaan laut. Dengan ketinggian yang sangat bervariasi tersebut, memiliki lereng yang cukup curam dan berpotensi terjadinya tanah longsor. Selain itu, aktivitas pertambangan batu bara sekitar desa membuat tanah menjadi tidak stabil. Penelitian ini bertujuan untuk memetakan wilayah yang rawan terjadi gerakan tanah di Desa Kolok Mudik. Metode yang digunakan dalam penelitian ini adalah menggunakan overlay peta dengan menggunakan aplikasi Sistem Informasi Geografis (SIG). Parameter yang digunakan dalam model ini adalah jenis tanah, jenis batuan, kemiringan lahan, formasi geologi, penggunaan lahan, dan curah hujan. Dalam proses pemetaan, setiap parameter memiliki skor klasifikasi yang dikalikan dengan bobot masing-masing parameter. Berdasarkan hasil pengolahan data, diperoleh hasil bahwa kerentanan gerakan tanah di Desa Kolok Mudik berada pada kategori sedang hingga tinggi.      
Analisis Logam Berat Pada Lahan Bekas Tailing Emas Berdasarkan Sifat Fisik Kimia Tanah Syari Rahma Yanti; Rika Ampuh Hadiguna; Fitri Nauli; Arif Algifari; Tedy Agung Cahyadi; Rika Ernawati
Justek : Jurnal Sains dan Teknologi Vol 7, No 2 (2024): Juni
Publisher : Unversitas Muhammadiyah Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Abstract:  Heavy metals are considered pollutants because its have a toxic effect on an organism if they exceed a certain concentration. The purpose of this study is to determine the characteristics of soil materials based on the physical and chemical properties of the soil. The method used to process the data is using the Soil Chemical Properties Assessment criteria while the texture class is determined based on the Texture Triangle. The result of the physical and chemical properties analysis of the soil is to determine the fertility level of the tailings soil. The analysis was carried out by assessing the physical properties of the soil, namely soil texture, while the assessment of soil chemical properties was soil pH, Cationic Exchange Capacity (CEC), Base Saturation (BS), C-Organic, and metal percentages of Potassium (K), Calcium (Ca), Magnesium (Mg), Sodium (Na). The results of the study showed that the tailings soil had a pH value of 8.89 including the lime category, this was in line with the CEC value and the alkaline saturation was classified as high and very high with values of 31.33% and 94.67 cmol/kg, as well as the values of Potassium (K), Calcium (Ca), Magnesium (Mg), Sodium (Na) which showed very high amounts in the results of the TSF 56 tailings soil testing laboratory. However, the value of C-Organic content is 0.16%, including a very low category. The permeability value of tailings soil is quite low, which is 0.21%, this is in line with the texture of tailings soil which is dominated by clay and dust so that the ability to drain water is very low.Abstrak: Logam berat dianggap sebagai pencemar karena memiliki efek racun pada suatu organisme apabila sudah melebihi konsentrasi tertentu. Tujuan dari penelitian ini adalah untuk mengetahui karakteristik material tanah berdasarkan sifat fisik dan kimia tanah. Metoda yang digunakan untuk mengolah data adalah menggunakan kriteria Penilaian Sifat Kimia Tanah sedangkan kelas tekstur ditentukan berdasarkan motoda Segitiga Tekstur. Hasil dari analisis sifat fisik dan kimia tanah adalah untuk mengetahui tingkat kesuburan tanah tailing. Analisis dilakukan dengan menilai sifat fisika tanah yaitu tekstur tanah, sedangkan penilaian sifat kimia tanah yaitu pH tanah, Kapasitas Tukar Kation (KTK), Kejenuhan Basa (KB), C-Organik, dan persentaase logam Kalium (K), Kalsium (Ca), Magnesium (Mg), Natrium (Na). Hasil penelitian menunjukkan tanah tailing memiliki nilai pH sebesar 8.89 termasuk kategori kalis, hal ini sejalan dengan nilai KTK dan kejenuhan basa tergolong tinggi dan sanggat tinggi dengan nilai 31,33 % dan 94,67 cmol/kg, begitupun dengan nilai Kalium (K), Kalsium (Ca), Magnesium (Mg), Natrium (Na) yang menunjukan jumlah yang sanggat tinggi pada hasil laboratorium pengujian tanah tailing TSF 56. Namun untuk nilai kandungan C-Organik adalah 0.16% termasuk katagori sangat rendah. Untuk nilai permeabilitas tanah tailing cukup rendah yaitu 0.21 %, ini sejalan dengan tesktur tanah tailing yang didominasi oleh liat dan debu sehingga kemampuan melolokan air sangat rendah.
Co-Authors Andri Van Deni Aulia Hidayat Burhamidar Dwi Wulan Syakira Fitri Nauli Herdian Pratama Ilham Gilang Ramadhan Muhammad Irvan Putri, Fairus Atika Redanto Rahma Doni Rika Ampuh Hadiguna Rika Ernawati Siti Aisyah Syari Rahma Yanti Tedy Agung Cahyadi Wahyudi Ardiansyah