Biodiesel Production from Sudanese Jatropha curcas Seed by The Alkali-Catalyzed Transesterification Process and Its Analysis by Gas Chromatography

Sudan is highly dependent on diesel. Diesel is used in agriculture machines, transportation, and other applications. This study has been carried out to produced biodiesel from Jatropha curcas seed oil. Jatropha was chosen because it is not edible, therefore it will not pose a new problem to humans regarding food competition. This research successfully extracted oil from Jatropha curcas seed using n-hexane solvent with yield 39%. The oil than converted to biodiesel by alkaline transesterification process with a conversion yield 92 %. The properties such as flash point, acid value, viscosity, iodine value, density, copper corrosion, cetane number, sulphated ash, pour point, free glycerol, and total glycerol contents were 174 oC, 0.17 mg KOH/g, 8.912 mm2/s, 102 g I2/100 g, 895.8 kg/m3, class1, 51, 0.0047 %, -3 oC, 0.01 %,0.03 %, respectively. These quantities obtained were met most of the biodiesel standards that are ASTM D6751, EN14214, and ASTM D975. The GC data showed the fatty acid methyl ester (FAME) has a 12-20 carbon chain and still has monoglycerides, diglycerides, and triglycerides

The Influence of Reciprocal Learning Model on Mathematics Learning Achievement of Grade X Students at SMAN 1 Tinambung

This study is experimental research using the quasi-experimental design. This study aims to describe mathematics learning achievement of students taught by using reciprocal learning model is higher than using conventional learning model. This research was conducted in SMAN 1 Tinambung. The populations in this study were all students of class X MIA SMAN 1 Tinambung. The sample of this study included two classes, namely the experimental class and the control class. Data were collected by using observation, questionnaires, and learning achievement tests. Data analysis techniques were descriptive analysis and inferential analysis by using SPSS 23 for windows. Descriptive statistic analysis used N-Gain showed that the average score of mathematics learning achievement for the control class was 0.66 while for the experimental class was 0.75. As for the hypothesis test analysis that used a t-test (independent sample test), the significant value obtained was 0.027 < 0.05, which means mathematics learning achievement of students taught by using reciprocal learning model is higher than that of students taught by using conventional learning model

Sumatra Barat Plakat Panjang

399hal.; 18c

Sumatera Barat Plakat Panjang

399 hal.;ill.;21 c

Cerita - Cerita Lama Dalam Lembaran Sejarah

xvi, 210 hlm.; 16 x 2

Sumatera Barat Hingga Plakat Panjang

652 hal.;ill.;21 c

Sumatra Barat hingga plakat panjang

652 p.; 20 cm

Sumatra Barat Plakat Panjang

Jakarta396 hlm. 21 cm

PEMODELAN SLIDING MODE CONTROL UNTUK REGULASI TEGANGAN KELUARAN DC-DC ISOLATED FULL BRIDGE CONVERTER

Technological developments in electronic components and circuits are capable of producing a direct current (DC) power supply system, which is produced by converting the input DC voltage to a higher or lower output DC voltage. To enhance energy conversion efficiency, precise and responsive control is essential. One widely used approach is to employ a DC-DC full bridge converter topology. The objective of this study is to model a Sliding Mode Control (SMC) to regulated the output voltage of a DC-DC full bridge converter. The research involves designing and simulating the converter circuit subsystem, controller design, and specifying the equipment to closely resemble the in real conditions. Through experimentations, it is observed that the designed controller meets the expected specifications allowing the converter to simulate stable output voltage regulation. The SMC methods is chosen for its adaptive and nonlinear nature, enabling it to produce a constant output voltage even when the input voltage from the DC source varies. The input DC voltage specification is 24 V, while the output voltage generates 48 V. MATLAB/Simulink is employed for simulation to design the entire system and present the research result in graphical form. Keyword: Fuel Cell, DC-DC Full Bridge Converter, Sliding Mode Control, Voltage Regulation

Pemodelan Sliding Mode Control Untuk Regulasi Tegangan Keluaran Dc-Dc Isolated Full Bridge Converter,

Perkembangam teknologi komponen dan rangkaian elektronika mampu menghasilkan sistem penedia daya tegangan searah (Direct Current/DC), yang dihasilkan melalui konversi tegangan DC masukan ke bentuk tegangan DC keluaran yang lebih tinggi atau lebih rendah. Dalam upaya meningkatkan efisiensi konversi energi, dibutuhkan kontrol yang presisi dan responsif. Salah satu cara yang banyak digunakan adalah dengan menggunakan rangkaian konverter dengan topologi DC-DC full bridge converter. Tujuan dari penelitian ini berupa pemodelan kontroler SMC (Sliding Mode Control) untuk meregulasi tegangan keluaran dari DC-DC full bridge converter. Dalam penelitian ini akan dilakukan dengan merancang dan mensimulasikan sub sistem rangkaian konverter, desain kontroler, serta spesifikasi alat yang mendekati keadaan ril. Berdasarkan pengujian ini didapatkan bahwa rancangan kontroler yang dibuat telah sesuai dengan spesifikasi yang diharapkan dimana konverter mampu mensimulasikan regulasi keluaran tegangan yang cukup stabil. Dalam implementasinya, metode SMC ini digunakan karena bersifat adaptif dan nonlinier sehingga dapat menghasilkan keluaran tegangan yang konstan meskipun ada yang bervariasi tegangan dari sumber DC. Spesifikasi pada tegangan masukan DC adalah 24 V, sedangkan pada tegangan keluaran menghasilkan 48 V. Penelitian yang dilakukan dalam penulisan ini menggunakan simulasi dari aplikasi MATLAB/Simulink dalam merancang keseluruhan sistem dan menampilkan hasil penelitian dalam bentuk grafik