Journal of Science and Application Technology (JSAT - Institut Teknologi Sumatera)
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Studi Ekstraksi Bijih Emas Asal Pesawaran dengan Metode Pelindian Agitasi dalam Larutan Sianida
Get PDFResearch on the extraction of gold ore from Pesawaran, , Lampung, Indonesia, was carried out using the agitation leaching method in cyanide solution. This study aimed to obtain information on the use of conventional cyanidation methods for extracting gold from the Pesawaran gold ore. The ore preparation was carried out in the form of crushing, grinding and sieving to obtain samples with fraction sizes of -60 + 100 mesh, -100 +150 mesh, -150 + 200 mesh and -200 mesh. The ore characterization was performed using XRD, XRF, SEM-EDX, and wet chemical analysis. The XRD analysis showed that the main mineral phases were silica, hematite, aluminium hydroxide and orthoclase. The major constituents of the ore were Si (53,628%), Fe (15,996%), K (19,744%) and Al (8,045%). The Au content was determined by wet chemical analysis and was found to be 9.67 ppm. The experimental results show that the highest percentage of gold extraction of 83.33% was obtained using sodium cyanide at a concentration of 1000 ppm, a percent solids of 40% and a grain size of 200 mesh. Higher gold extraction was not achieved despite the use of a high cyanide concentration was probably because the remaining gold was not properly liberated. The results of SEM-EDX analysis showed that the gold grain size was <20 µm, while the grinding was performed only to a sieve size of -200 mesh (74 µm)
Electrical and optical properties of Ga-doped ZnO thin films deposited by DC magnetron sputtering
Get PDFThe electrical and optical properties of Ga-doped ZnO (GZO) thin film prepared by direct current (dc) magnetron sputtering were investigated. The GZO thin film was deposited on a glass substrate at a substrate temperature (Ts) of room temperature (RT), 150 °C, and 200 °C using DC power of 100 W and an Ar gas flow rate of 450 sccm. The thickness of films was maintained at about 200 nm by controlling the deposition rate of about 12.5 nm/minute. The result showed that the electrical properties improved with increasing Ts. The films deposited at Ts of 200 °C showed the lowest resistivity, highest hall mobility, and carrier concentration compared to other Ts. The average transmittance of the films in the visible range (380-750 nm) was approximately 86.04%. The value of the optical band gap (Eg) was approximately 3.8 eV. The results suggested that GZO films deposited by DC magnetron sputtering at Ts of 200 °C can be applied to transparent conducting oxide (TCO) as an electrode in optoelectronic applications such as solar cells, LEDs and display technology
Pengaruh Hubungan E-learning Dalam Mata Kuliah MAFIKI di Institut Teknologi Sumatera Menggunakan Metode Wilcoxon
Get PDFTujuan dari penelitian ini adalah untuk menganalisis perbedaan nilai matematika, fisika, dan kimia dasar pada Tahap Persiapan Bersama (TPB) sebelum dan sesudah dilaksanakannya program E-Learning. Program E-Learning merupakan salah satu media pembelajaran di ITERA dengan memanfaatkan teknologi internet yang memungkinkan terjadinya interaksi pembelajaran dari mana dan kapan saja dengan karakteristik interaktif, mandiri, mudah diakses, dan memungkinkan adanya pengayaan melalui internet. Penelitian ini merupakan penelitian kuantitatif, di mana data diperoleh dari web siakad ITERA. Pengolahan data dilakukan dengan menerapkan metode statistika non parametrik yaitu Uji Wilcoxon yaitu pengujian untuk data sebelum dan sesudah pelaksanaan E-Learning. Setelah dianalisa diperoleh kesimpulan bahwa terdapat perbedaan nilai dengan metode konvensional dan metode e-learning. Dimana metode konvensional jauh lebih efektif dibandingkan e-learning
Pengaruh Komposisi Campuran Minyak Sereh Wangi dan Minyak Cengkeh terhadap Unjuk Kerja Mesin Diesel
Get PDFThe increase in fuel prices makes the use of essential oils as a natural bio-additive in diesel engines much in demand. This is because essential oils are believed to have good content to improve engine performance and reduce fuel consumption. In this research, essential oils used are citronella oil because they contain carboxylic compounds (-COOH) and clove oil which has the advantage to prevent corrosion. The aim is to improve engine performance and reduce fuel consumption can also prevent corrosion. This research was conducted by mixing citronella oil and clove oil with diesel fuel with a percentage of 1%, 0.5%, and 0.1% of the total volume. The diesel engine is operated with a loading variation of 200, 400, 600, 800, 1000, 1200, 1400, 1600, 1800, and 2000 W at a constant engine speed of 1500 rpm. The variables measured and calculated in this experiment are power, torque, Brake Mean Effective Pressure (BMEP), Specific Fuel Consumption (SFC). The results showed that the addition of citronella oil and clove oil to diesel fuel with a percentage of 0.1%, 0.5%, and 1% significantly reduced fuel consumption by 14.6%, 12.9%, and 18.3%, respectively. The maximum fuel reduction from mixed oils is only 0.086 liters/hour at 1000W loads with 1% bio-additives content
Karakteristik dan Aplikasi Selulosa Kulit Jagung Pada Pengembangan Hidrogel
Get PDFCorn is one of the staple food crops widely consumed by Indonesians, thus has potensial in producing an abundant amount of corn husk waste. Cellulose contained in corn husk is about 44%, so the material has the potential to be source of natural fiber cellulose. The development of hydrogels from natural polymers such as cellulose is very promising especially for biomaterial application. Cellulose fiber was obtained through several stages: dewaxing, pulping, delignification, bleaching and cellulose purification. This study aimed to determine the most effective solvent in cellulose extraction of corn husk, the research carried out with different solvent such as, hydrogen peroxide (H2O2), sodium hypochlorite (NaOCl) and hydrocloric acid (HCl). Based on the functional group formed on the analysis of FTIR, shows that the extraction method using H2O2 as solvent can remove hemicellulose and lignin from the cellulose structure and the most white cellulose fiber obtained from the extraction with H2O2 solvent. Cellulose obtained from previous step was used for hydrogel production. The hydrogel showed different absorption capacity depend on temperature and ratio of glutaraldehide to cellulose. The highest water absorption capacity of 250% obtained by hidrogel with ratio 1:2 at 25oC
Identifikasi Struktur Geologi dan Petrografi di sekitar Observatorium Astronomi Lampung Gunung Betung
Get PDFLampung Astronomical Observatory (LAO) is located on Betung Mountain which is quite close to the Semangko active fault zone. Betung Mountain is part of the Bukit Barisan which is located west of the city of Bandar Lampung. This mountain has an altitude of about 1200 meters above sea level. There are 6 interesting stations. Most of the stations are located on the upper slopes of Betung Mountain. In the Talang Aji area, there are 2 springs. The other 4 stations consist of waterfalls with varying heights: Talang Teluk waterfall (30 m), Talang Rabun waterfall (20 m), Betung waterfall consists of two minor terraced waterfalls with a height of 5 and 10 m respectively, and Kubu Jambu waterfall (12 m). In general, the orientation of the faults of Mt. Betung was northeast-southwest. The faults are also associated with several waterfalls found in the field. From the joint data processing, it can be interpreted that the fault formed on Betung Mountain is normal. The lithology of Betung Mountain is dominated by volcanic deposits in the form of tuffs. In certain rivers, there are outcrops of lava igneous rock in the form of Andesites. Andesite lava in the northern and southern parts of Betung Mountain has different characteristics
Uji Performa Gasoline Engine menggunakan bioaditif cengkeh dengan bensin berkadar oktan 90
No full textGlobally, the demand for fuels is ever-increasing and so is the demand for fuel additives. A fuel additive is a substance added in small quantities to increase the performance of the engine, decrease fuel consumption and reduce emission. The fuel additives have no specific set of raw materials or ingredients. Every fuel additive is different from the other in many ways of raw materials and ingredients to produce these additives. In many cases, fuel additives have made by chemical materials as additives for a gasoline engine. However, the optimal parameters for the reduction of fuel consumption are not clear. Accordingly, the present study performs a mixing additive material in the form of clove oil with pure gasoline fuel with a percentage of 1%, 0,6% and 0,3% from a total volume of gasoline to be tested. Then the mixing of the additive and gasoline is tested into the gasoline engine by varying the load using 200, 400, 600, 800, 1000, 1200, 1400, 1600, 1800 and 2000 Watt power with a fixed engine rotation of 2500 rpm. The results show that the reduction of fuel consumption respectively. Results showed that the addition of 1%, 0.6% and 0.3% clove oil into a 90 octane gasoline reduced fuel consumption by 10.6%, 18.2% and 15.4% respectively. Maximum reduction of fuel consumption was 28.6% at 800 W electrical load with 0.6% of clove oil additive
Active contour driven by scalable local regional information on expandable kernel
Get PDFAn active contour that uses the pixel’s intensity on a set of expandable kernels along the propagating contour for image segmentation is presented in this paper. The objective is this study is to employ the scalable kernels to attract the contour to meet the desired boundary. The key characteristics of this scheme is that the kernels gradually expand to find an object’s boundary. So this scheme could penetrate to the concave boundary more effective and efficient than some other schemes. If a Gaussian kernel is applied, it could trace the object with a blurred or smooth boundary. Moreover, the directional selectivity feature enables in capturing two edge’s types with just one initial position. Its performance showed more desirable segmentation outcomes compared to the other existing active contours using regional information when segmenting the noisy image and the non-uniform (or heterogeneous) textures. Meanwhile, the level set implementation enables topological flexibility to our active contour scheme
Analisis Korelasi Sistem Kuliah Lintas Prodi dengan Keefektifan Pembelajaran Mahasiswa Program Studi Matematika Institut Teknologi Sumatera (ITERA)
Get PDFKuliah Lintas Prodi adalah kegiatan mengikuti mata kuliah yang ditawarkan di luar mata kuliah Program Studi Matematika. Penelitian ini bertujuan untuk mengetahui hubungan antara keberlakuan sistem kuliah lintas prodi dengan keefektifan pembelajaran mahasiswa Program Studi Matematika Institut Teknologi Sumatera (ITERA). Hal ini melatarbelakangi permasalahan psikologis mahasiswa Program Studi Matematika angkatan 2017 dan 2018. Metode penelitian yang digunakan dalam penelitian ini adalah metode statistik dan pengujian hipotesis dengan Uji Korelasi Pearson dengan menggunakan variabel yaitu skor sistem kuliah lintas prodi dan skor keefektifan dalam belajar. Teknik pengumpulan data yang dilakukan adalah memperoleh data dari kuisioner dengan hasil 52 responden, yang berikutnya digunakan teknik penyajian skor hasil kuisioner. Dari hasil penelitian yang dilakukan maka dapat disimpulkan bahwa tidak terdapat korelasi yang signifikan antara sistem kuliah lintas prodi dengan keefektifan pembelajaran mahasiswa Program Studi Matematika Institut Teknologi Sumatera (ITERA)
Analisis Korelasi Luas Lahan Serta Ekspor Kopi Lampung Terhadap Ekspor Kopi Indonesia
Get PDFLampung merupakan produsen kopi terbesar kedua dan sumber pengekspor kopi pertama di Indonesia. Sementara Indonesia merupakan pengekspor kopi terbesar ke-4 di dunia. Kopi menjadi salah satu sumber pendapatan devisa utama negara. Paper ini membahas tentang hubungan antara luas lahan kopi di Indonesia dengan jumlah kopi yang diekspor. Hubungan antara eksport kopi lampung dengan eksport kopi Indonesia turut menjadi pokok bahasan utama pada jurnal ini. Data diperoleh dari Badan Pusat Statistik yang diolah secara kuantitatif. Pengolahan data dilakukan dengan menerapkan metode statistika non parametrik yaitu uji korelasi Spearman dengan bantuan SPSS 25. Hasil penelitian menunjukkan bahwa luas lahan kopi cukup berpengaruh terhadap jumlah ekspor kopi Indonesia, begitu pula dengan jumlah ekspor kopi Lampung yangpengaruhnya tinggi terhadap jumlah ekspor kopi Indonesia