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All Journal POSITRON Komunikasi Fisika Indonesia SEMIRATA 2015 Abdimas Indonesian Journal Science, Technology, and Communication Journal
Lazuardi Umar
Fakutas Sains dan Teknologi Universitas Jambi, Jambi
Religion Computer Science & IT Earth & Planetary Sciences Economics, Econometrics & Finance Education Electrical & Electronics Engineering Energy Engineering Industrial & Manufacturing Engineering Materials Science & Nanotechnology Physics Social Sciences

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KARAKTERISASI DAN SIMULASI DIODA PN MEMPERGUNAKAN ALAT UJI OTOMATIS BERBASIS MIKROKONTROLER ATMEGA8A Oktavia, Dian Putri; Hamzah, Yanuar; Umar, Lazuardi
Komunikasi Fisika Indonesia Vol 13, No 12 (2016)
Publisher : Komunikasi Fisika Indonesia

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Abstract

An automated test platform for I-U curve diode characterisation based on microcontroller of Atmega8A is presented. Four types of diodes; 1N4007, 1N5401, 1N5392, and 1N4148 were characterized at temperature 303K using step voltage (dU) of 1mV, 5mV, 10mV, 20mV, 50mV, 100mV, and 500mv respectively. The temperature influences on diode was observed by putting diodes in adiabatic temperature chamber at three different temperatures of 313K, 323K, and 333K, the I-U curve of diodes are then measured. The results show an exponentially diodes I-U curve at quadrant I (forward bias region). For diode parameters, the I-U curve were then modeled and simulated after diodes equation and resulted an maximum absolute error 10.57% of full scale measurement
SIMULASI 3 DIMENSI DISTRIBUSI PANAS PLAT KNALPOT MOBIL UNTUK ELEMEN TERMOELEKTRIK Adli, Wildan; Tambunan, Walfred; Umar, Lazuardi
Komunikasi Fisika Indonesia Vol 13, No 12 (2016)
Publisher : Komunikasi Fisika Indonesia

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Abstract

This study simulates the distribution of heat in the conductor plate micro energy generation based module Thermoelectric Generator (TEG) type 40-40-10 / 100 to optimize the absorption of heat from the vehicle exhaust waste heat. The module has a maximum operating temperature of 423K. The modeling is done using MATLAB with a modified diffusion equation by application of 900K of temperature as boundary condition on the surface of the base plate which is in contact with the heat source. The plate with aluminum material modeled in varies form of solid, hollow, hollow gitter, hollow heatsink, with dimensions of 110mm long, 60mm wide, 30mm thick base and 30mm thick bulge. The best temperature drop obtained for ΔT = 178,67K (19.85%) produced by the shape of a hollow heatsink plate. The resulting temperature of this model is then lowered back with varying types of material such as aluminum, copper, iron, and stainless steel, as well as by varying the number of TEG array that is 1 to 4-arrays, each array consisting of two modules. Drop in temperature that comes closest to the maximum TEG operating temperature is a drop in temperature that generates the final temperature of 402K, which comes from hollow-with-heatsink stainless steel plate with 50mm of thick and 4-arrays formation.
PENGOLAHAN ISYARAT METODE DIFERENSIAL UNTUK LINIERISASI SENSOR KOIL DATAR Pertiwi, Kisna; Malik, Usman; Umar, Lazuardi
Komunikasi Fisika Indonesia Vol 13, No 12 (2016)
Publisher : Komunikasi Fisika Indonesia

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Abstract

Flat coil sensor works by evaluating changes the mutual inductance of the measuring object immersed in a magnetic field of coil. The spiral coil detects without a physical contact with object made on FR4 Printed Circuit Board (PCB). LC-oscillators are used to evaluate change the inductances of two identical sensors in a differential structure with a measured object of copper beryllium (CuBe) moving parallel between the sensors. Flat coil evaluation sensor using LC oscillator produces the eigen frequency of 1MHz up to 2MHz. The linearization of flat coils are carry out using output differential between two oscillator and shown a linear output.
ANALISIS PENGARUH PUPUK KCl TERHADAP PARAMETER KELEMBABAN PADA TANAH INSEPTISOL UNTUK PENGEMBANGAN SENSOR KELEMBABAN TANAH (SOIL MOISTURE SENSOR) Samsidar, Samsidar; Oktamuliani, Sri; Umar, Lazuardi
SEMIRATA 2015 Prosiding Bidang Fisika
Publisher : SEMIRATA 2015

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Abstract

Pengembangan sensor kelembaban tanah (soil moisture sensor) berdasarkan prinsip spektroskopi impedansi merupakan salah satu metode pengembangan sensor yang saat ini cukup diunggulkan. Metode Spektroskopi Impedansi bekerja berdasarkan prinsip dimana status impedansi kompleks suatu sistem dianalisa dalam jangkauan frekuensi tertentu. Pada penelitian ini dilakukan studi validasi sensor kelembaban tanah dengan penambahan pupuk KCl pada tanah inseptisol terdefinisi. Tahap awal penelitian digunakan sensor dengan panjang sonde 100 mm  dan diameter 7 mm untuk mengukur kelembaban tanah Inseptisol dengan kelembaban terdefenisi 10%, 20%, 30% dan 40%. Untuk pengembangan sensor kelembaban tanah divalidasi dengan penambahan pupuk KCl terhadap variasi kelembaban tanah Inseptisol yang terdefenisi dan kemudian diukur nilai konduktivitasnya, dimana nilai konduktivitas  berkaitan dengan nilai Impedansi. Hasil analisis kuantitatif menunjukkan bahwa penambahan pupuk KCl pada kelembaban 10% dan 20%, sensor kelembaban tanah masih memiliki akurasi yang cukup tinggi, sedangkan pada kelembaban 30% dan 40%, sensor kurang akurat dan hasil analisis kualitatif bahwa sensor kelembaban tanah lebih tepat digunakan pada tanah yang tidak mengandung pupuk KCL. Katakunci: KCl, Inseptisol, Sensor Kelembaban
Identification and Classification of Thiamine with Amperometric Biosensor Based on Saccharomyces cerevisiae and Principal Component Analysis Umar, Lazuardi; Rosandi, Vira Annisa; Nainggolan, Leonardus Riski; Setiadi, Rahmondia Nanda; Linda, Tetty Marta
POSITRON Vol 13, No 1 (2023): Vol. 13 No. 1 Edition
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam, Univetsitas Tanjungpura

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26418/positron.v13i1.59432

Abstract

Vitamin B1 (thiamine) plays an important role in various metabolic processes and is one of the main factors in the body's health. Thiamine excess and deficiency in the body might cause a variety of diseases such as shortness of breath, beriberi, and heart failure, hence thiamine levels must be detected as a reference for intake. The present research detected thiamine using the amperometric biosensor method and the yeast Saccharomyces cerevisiae as a bioreceptor. Dissolved oxygen (DO) level measurement parameters are considered based on yeast cell metabolism. Thiamine was treated with various concentrations of 15 mM, 30 mM, 45 mM, 60 mM, and 75 mM. The measurement results are in the voltage range of 1912–1964 mV, where the addition of thiamine causes an increase in the reproducibility and growth rate of yeast cells. The ideal characteristics of the biosensor based on the parameters of sensitivity, linearity, and stability was also carried out, which resulted in successive biosensor measurements of 0.925 mV/mM, a correlation coefficient of r = 0.9868, and a decrease in the voltage response of the biosensor up to 4.97% from its initial activity. The measured data were grouped and classified using principal component analysis (PCA), which resulted in a total accumulated data variance percentage of 84.5% and an eigenvalue > 1 for both PCs. It is intended that the findings of this research can be utilized as a reference for controlling vitamin consumption levels that have an impact on health.
Quantitative Caffeine Analysis in Robusta Coffee Utilizing Amperometric Biosensing Technology Rosandi, Vira Annisa; Umar, Lazuardi; Setiadi, Rahmondia Nanda; Rini, Ari Sulistyo; Erwin, Erwin; Yanuar, Yanuar; Linda, Tetty Marta
POSITRON Vol 13, No 2 (2023): Vol. 13 No. 2 Edition
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam, Univetsitas Tanjungpura

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26418/positron.v13i2.70008

Abstract

Consuming caffeine in inappropriate amounts can disrupt various aspects, especially health. Controlling intake by knowing the caffeine levels in coffee is necessary to reduce the potential negative impacts. This research focuses on the detection of caffeine in Robusta coffee at two different concentrations (1:10 and 1:20 g/mL) and its relationship with yeast metabolism. An amperometric biosensor with a transimpedance amplifier to measure caffeine levels is used which has the advantages of sensitivity, cost-effectiveness, real time monitoring, biocompatibility, and reliable measurements. The data were statistically analyzed using ANOVA and visualized using Principal Component Analysis (PCA). The results revealed a concentration -dependent decrease in biosensor readings as caffeine levels increased (0.1, 0.5, 1, 1.5, and 2 mM), indicating caffeine's ability to inhibit yeast oxygen consumption and oxygen-dependent metabolic processes. The sensitivity of the biosensor in detecting caffeine is 36.66 mV/mM. PCA uncovered complex patterns, relationships, and variations within the caffeine data. PC1 and PC2, the first two principal components, collectively explained 86.3% of the data's variance. Eigenvalues for both PCs were greater than 1, highlighting their significance in understanding the dataset's complexity. This research enhances our understanding of caffeine content in Robusta coffee and its effects on yeast metabolism, providing valuable insights for the coffee industry. This use of yeast biosensors offers efficiency, and adaptability that make that biosensor valuable in a variety of scientific and industrial contexts.
Pengembangan Kewirausahaan Mahasiswa Melalui Produksi Kopi- Pro Feliatra, Feli; Batubara, Ummi Mardhiah; Nursyirwani, Nursyirwani; Umar, Lazuardi; Zevira, Bella Permata; Gustina, Julia; Alfarisy, M. Phyto; Feliatra, Pamela Isya
Abdimas Indonesian Journal Vol. 4 No. 2 (2024)
Publisher : Civiliza Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.59525/aij.v4i2.469

Abstract

Pro coffee is a coffee drink enriched with B.cereus consortium bacteria. Bacillus cereus is a single cell protein that is rich in protein. This program aims to develop student entrepreneurial activities by implementing the results of previous research, namely utilizing probiotic bacteria for healthy coffee entrepreneurship by adding probiotic bacteria to coffee drinks. The method used to provide lectures and practices about professional coffee processing to students involved in this service. This service activity is carried out in four stages, namely: Training and Competency Improvement. Training and competency improvement activities are carried out as an effort to increase the knowledge and competence of Partners and students in processing Pro coffee. The results of the service show that students are able to improve: 1) Knowledge of making media for developing probiotic bacteria so that they are suitable for human consumption; 2) Making probiotic starter (Bacillus cereus SN7); 3) Pro coffee making; 4) Pro coffee packaging; and 5) Marketing of pro coffee products.
Green-synthesized ZnO and Ag nanoparticles: A comparative study of optical, morphology and structural properties for photocatalytic applications Hamzah, Yanuar; Emrinaldi, Tengku; Dewi, Rahmi; Rini, Ari Sulistyo; Umar, Lazuardi; Simatupang, Mediniah Putri; Rabiah, Rabiah; Noferdi, Muhammad Deri
Science, Technology, and Communication Journal Vol. 5 No. 3 (2025): SINTECHCOM Journal (June 2025)
Publisher : Lembaga Studi Pendidikan dan Rekayasa Alam Riau

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.59190/stc.v5i3.307

Abstract

In this study, zinc oxide (ZnO) and silver (Ag) nanoparticles were synthesized using Annona muricata leaf extract as a reducing and stabilizing agent with variations in the molar ratio of 1:3, 1:5, and 1:7. Optical characterization using UV-Visible spectroscopy revealed that the variations of molar ratio influence the absorption peak and band gap energy of the resulting ZnO and Ag. UV-Vis results show that the molar ratio 1:5 was optimal for synthesizing ZnO and Ag. The band gap value of synthesized ZnO and Ag at a 1:5 molar ratio was 3.27 eV and 2.01 eV, with absorption peaks at 355 nm and 435 nm respectively. XRD characterization shows that ZnO nanoparticles has a hexagonal wurtzite structure with lattice parameters of a = 76 Å and c = 4. 95 Å and for Ag nanoparticles has a face centered cubic structure with lattice parameters a = b = c is 4.15 Å. Annona muricata leaves extract shows photocatalytic properties that can be applied to the degradation of polluted water. This shows that ZnO nanoparticles via green synthesis using Annona muricata leaf extract is a very simple, low-cost and environmentally friendly method.
Co-Authors Alfarisy, M. Phyto Batubara, Ummi Mardhiah Dian Putri Oktavia, Dian Putri Erwin Erwin Feliatra, Feli Feliatra, Pamela Isya Gustina, Julia Kisna Pertiwi, Kisna Nainggolan, Leonardus Riski Noferdi, Muhammad Deri Nursyirwani, Nursyirwani Rabiah Rabiah Rahmi Dewi Rahmondia N. Setiadi Rini, Ari Sulistyo Rosandi, Vira Annisa Samsidar Samsidar Simatupang, Mediniah Putri Sri Oktamuliani Tengku Emrinaldi Tetty Marta Linda Usman Usman Walfred Tambunan Wildan Adli, Wildan Yanuar Hamzah Yanuar Yanuar, Yanuar Zevira, Bella Permata