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All Journal Al-Fiziya: Journal of Materials Science, Geophysics, Instrumentation and Theoretical Physics VALENSI Jurnal Fisika Unand JFA (Jurnal Fisika dan Aplikasinya) Spektra: Jurnal Fisika dan Aplikasinya Eksakta : Berkala Ilmiah Bidang MIPA BEES: Bulletin of Electrical and Electronics Engineering Makara Journal of Science
Yuniarti, Elvan
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Aerospace Engineering Agriculture, Biological Sciences & Forestry Astronomy Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Civil Engineering, Building, Construction & Architecture Computer Science & IT Control & Systems Engineering Decision Sciences, Operations Research & Management Earth & Planetary Sciences Electrical & Electronics Engineering Energy Engineering Environmental Science Materials Science & Nanotechnology Mathematics Mechanical Engineering Physics

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SYNTHESIZE OF TiO2 NANOPARTICLES BY PLANETARY BALL MILL FOR DYE-SENSITIZED SOLAR CELLS (DSSC) PHOTOELECTRODE APPLICATION Nurlaela, Ai; Yuniarti, Elvan; Saptari, Siti Ahmiatri
Spektra: Jurnal Fisika dan Aplikasinya Vol. 8 No. 2 (2023): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 8 Issue 2, August 2023
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.082.02

Abstract

In this study, the production of TiO2 nanoparticles from microcrystalline powder was accomplished using the high-energy ball milling (HEBM) technique. Three samples were milled for 0.5, 1, and 1.5 hours. The unmilled powder was also characterized as a comparison. The X-ray diffraction (XRD) technique was utilized to investigate the changes in the microstructure of the milled powders over time. The XRD curve of milled samples showed the broadening of the diffraction peaks, which indicates a decrease in particle size after the milling process. Using the Debye–Scherrer relation, obtain the particle size that decreased from 138.43 nm before milled to 76.65 nm after 0.5 hours milled, 90.63 nm after 1 hour milled, and 83.05 nm after 1.5 hours milled. XRD analysis also showed that TiO2 was in an anatase phase before and after milling. Furthermore, two samples of TiO2, unmilled and after 0.5 hours milled, were used as a working photoelectrode of DSSC with dye from mustard leaves. DSSC efficiency was measured with a 1000-watt halogen lamp. The efficiency of DSSC with photoelectrodes using TiO2 after 0.5 hours milled, which is 0.1715, was higher than using TiO2 before milled, which is 0,0987. The Large surface area in TiO2 enhances the efficiency of DSSC, indicating that the HEBM technique is quite suitable for producing these nanoparticles for this aim.
EXPERIMENTAL AND COMPUTATIONAL STUDY OF NITROGEN-DOPED TiO2 AS A PHOTOELECTRODE Saptari, Sitti Ahmiatri; Yuniarti, Elvan; Loua, Lamin Rene
Spektra: Jurnal Fisika dan Aplikasinya Vol. 8 No. 2 (2023): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 8 Issue 2, August 2023
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.082.03

Abstract

TiO2 has been widely used as a dye-sensitized solar cell (DSSC) photoelectrode, and attempts have been made to improve the performance of the photoelectrode by adding doping. This study aims to synthesize nitrogen (N) doped TiO2 as a photoelectrode. The research was carried out experimentally and computationally using X-Ray Diffraction (XRD) test equipment, Fourier Transform Infra-Red (FTIR), and quantum espresso software using the Density Functional Theory (DFT) method. XRD results showed that TiO2 has an anatase phase, and variations in the addition of nitrogen (doped N) of 10% w/w, 20% w/w, and 30% w/w did not produce a phase change. The FTIR results of N-doped TiO2 and TiO2 provide information on the functional groups of the samples. The wave number absorption area 1626 cm-1 indicates the presence of N-H bonds with a bending vibration mode. In addition, it can be seen that there is an N-H bond with a stretching vibration mode at wave number 3436 cm-1. Computational calculations searched the band gap energy of each variation of N doping, and each obtained was 3.2 eV; 2.54 eV; 2.35 eV; and 1.64 eV. The results of this study indicate that the N-doped TiO2 photoelectrode is expected to produce better DSSC efficiency because the addition of N-doped to TiO2 causes a decrease in the bandgap energy. The N doping effect causes a new energy level. The new energy level must be positioned close to the existing valence and conduction bands. As a result, the energy required for electrons to transition from the valence band to the conduction band is reduced, effectively reducing the energy gap between the two. This change in electronic structure facilitates more effortless movement of electrons, driving increased conductivity.
Sistem Monitoring Kualitas Air dan Pakan Otomatis Pada Akuarium Ikan Mas Koki Terintegrasi IoT Lestari, Dewi; Yuniarti, Elvan; Dinda Sari, Yayang
BEES: Bulletin of Electrical and Electronics Engineering Vol 4 No 3 (2024): March 2024
Publisher : Forum Kerjasama Pendidikan Tinggi (FKPT)

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.47065/bees.v4i3.4624

Abstract

Water is a living medium for goldfish, which greatly influences their lives. Water quality as a living medium for fish greatly influences the growth and development of goldfish; therefore, water quality must meet the needs of goldfish. Several water quality parameters that greatly influence fish life are temperature, degree of acidity (pH), and solid substances dissolved in water (TDS). The aim of this research is to design a monitoring system capable of measuring temperature, degree of acidity (pH), and solid substances dissolved in water based on the Internet of Things. This tool is used for an Internet of Things-based water quality monitoring system in goldfish aquariums, where the results obtained will be sent via smartphone to the Blynk application. And it can also provide food automatically and provide notifications if the water becomes cloudy. This tool is designed using an Arduino Uno, a Wemos D1 R2 controller, and sensors used to measure each parameter, namely the DS18B20 sensor, pH sensor, and TDS sensor. Then the feeder uses a servo to open the feed and an RTC as a timer. The results of this research conclude that the calibration results for the DS18B20 sensor have an average accuracy rate of 99% with a sensor error percentage of 1%, the pH sensor has an accuracy rate of 98.7% with an error percentage of 1.3%, and the TDS sensor has an accuracy rate of 94.59% with an error percentage of 5.41%.
Synthesis and Characterization of Optical Properties of Carbon Quantum Dots (CQD) Based on Mustard Green (Brassica juncea L) Leaf with Urea Addition Yuniarti, Elvan; Nurlaela, Ai
Jurnal Kimia Valensi Jurnal Kimia VALENSI Volume 9, No. 2, November 2023
Publisher : Syarif Hidayatullah State Islamic University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15408/jkv.v9i2.34164

Abstract

Carbon quantum dots (CQDs) are a class of fluorescent carbon nanomaterials. Carbon quantum dots (CQDs) were synthesized in this work from Mustard Leaves (Brassica juncea L) with the Addition of Urea via a microwave-assisted reflux method. This research aims to characterize CQDs' optical properties, energy gap, and emission under UV light computationally and experimentally. The studied optical properties obtained the maximum absorption peak observed from the UV-Vis spectrum of CQDs without urea shown at 233 nm. The UV-Vis spectrum of CQDs with the addition of urea (1 g, 1.5 g, and 2 g urea) has maximum absorption peaks at 424 nm, 422 nm, and 418 nm. The addition of urea causes a shift in the peak of the UV-Vis absorption spectrum towards red wavelengths (redshift). CQDs display bright green emissions when exposed to UV irradiation. In this work, the structures of CQDs of various forms (CQD-24, CQD-54, CQD-24-NH2, CQD-54-NH2) are theoretically studied in detail, and the results present both models (CQD-24, CQD-54) shows that the calculation results are in accordance with the experimental results, namely having a maximum UV-Vis absorption at 233 nm and in the range 200-400 nm. The results of calculations based on experiments show the same trend, namely that with the addition of urea, there is a shift in the absorption peak (redshift). The gap energy obtained also decreased with the addition of urea. CQDs solution emits yellow-green light.
First-Principles Calculations of Thermoelectric Properties of Fe-Based Full- Heusler Fe2CuSi Nurlaela, Ai; Nanto, Dwi; Azhar, Anugrah; Yuniarti, Elvan; Kristiantoro, Tony; Dedi, Dedi
Makara Journal of Science Vol. 28, No. 3
Publisher : UI Scholars Hub

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

Abstract

A first-principle study using density functional theory (DFT) and Boltzmann transport was conducted to evaluate the thermoelectric (TE) properties of an Fe-based full-Heusler alloy. The compound studied is Fe2CuSi with a Cu2MnAl-type structure. The electronic properties of Fe2CuSi were obtained using DFT calculations by running the Quantum ESPRESSO (QE) package. By contrast, TE properties, including electron thermal conductivity, electric conductivity, and Seebeck coefficient, were computed using a semi-empirical Boltzmann transport model solved through the BoltzTraP software at 50–1,500 K temperature range. The spin-orbit coupling effect on these properties was also evaluated, demonstrating notable effects on the results. Multiple electronic bands crossing the Fermi level for both spin directions were confirmed by the density of state curve, indicating the metallic behavior of Fe2CuSi. The magnitude of the figure of merit was determined by the Seebeck coefficient, electric conductivity, and electron thermal conductivity. In this study, the maximum dimensionless figure of merit was 0.027, reached at 1,000 K for the spin-down channel.
Dye Sensitized Solar Cells with X% Cu-TiO2 Photoelectrode Sensitized from Syzygium malaccense Fajriah, Nurul; Yuniarti, Elvan; Saptari, Sitti Ahmiatri
Jurnal Fisika dan Aplikasinya Vol 20, No 1 (2024)
Publisher : Lembaga Penelitian dan Pengabdian Kepada Masyarakat, LPPM-ITS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.12962/j24604682.v20i1.16611

Abstract

Abstract: Dye Sensitized Solar Cell preparation with x% Cu-TiO2 photoelectrode sensitized from Jamaica guava leaf dye (Syzygium malaccense) has been successfully made. This DSSC composed of x% Cu- TiO2 Photoelectrode synthesized by the doctor blading method with variation concentration Cu dopant at 0%, 1%, and 5%. Sensitizer (dye) made with technique maceration; electrolyte solution used an iodine solution, counter electrode with a carbon layer made from a candle flame; all the components are then arranged like a sandwich. The layers were characterized by X-ray diffraction to determine the phase, structure, and crystal size. X-ray diffraction characterization was carried out on all x% Cu-TiO2 layers. X-ray diffraction results show that has identified TiO2 anatase phase compound with a tetragonal crystal structure and has an average crystal size obtained from calculations using the Williamson Hall method for 0%, 1%, and 5% Cu doping fractions respectively are 60.28 nm, 43.32 nm, and 53.32 nm. UV-Vis's spectrophotometric characterization was carried out to determine the optical properties of the dye, and the results showed that Jamaica guava leaf dye has light absorption at a wavelength between 400-700 nm with a band gap energy of 1.728 eV. Furthermore, the current-voltage (IV) characterization was carried out to determine the efficiency of the solar cell. Based on the research results, the addition of Cu dopants as Photoelectrode can increase the efficiency of DSSC at a certain concentration. The highest efficiency achieved is 0.0036 % at 1% Cu doping concentration.  
Machine Learning Classification for Detecting Heart Disease with K-NN Algorithm, Decision Tree and Random Forest Hartono, Ambran; Dewi, Lizky Azka; Yuniarti, Elvan; Salsabila Tahta Hirani Putri; Harahap, Try Surya
EKSAKTA: Berkala Ilmiah Bidang MIPA Vol. 24 No. 04 (2023): Eksakta : Berkala Ilmiah Bidang MIPA (E-ISSN : 2549-7464)
Publisher : Faculty of Mathematics and Natural Sciences (FMIPA), Universitas Negeri Padang, Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/eksakta/vol23-iss04/461

Abstract

The heart is one of the most important organs for human; therefore, it needs to always be looked after and maintained properly. If it is not looked after and maintained properly, it will be at risk of disease. Currently, heart disease of various types still ranks first in deaths both in Indonesia and abroad. Various efforts continue to be developed by relevant scientists to detect it. Considering the importance of development efforts, in this research a machine-learning program was designing to classify heart disease as a detection system effort. In this article we will describe the analysis of the characteristics of the K-NN classifier, decision tree, random forest (accuracy, precision and recall), as well as determining the best classifier for detecting heart disease. To support the analysis of test results, Python and Google Colab programming has been implementation here. The best results obtained from the analysis of the application of these three models are the Decision Tree Classifier with accuracy, precision and recall values ​​of 90%, 87% and 88% respectively. These results indicate that this model has been successfully developing.
CAFFE VISITOR COUNTER BASED ANDROID ULTRASONIC SENSOR AND BLUETOOTH Lestari, Dewi; Yuniarti, Elvan
Al-Fiziya: Journal of Materials Science, Geophysics, Instrumentation and Theoretical Physics AL-FIZIYA JOURNAL OF MATERIALS SCIENCE, GEOPHYSICS, INSTRUMENTATION AND THEORETICAL PHYSICS VOL.8, N
Publisher : Physics Study Programme, Faculty of Science and Technology UIN Syarif Hidayatullah Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15408/fiziya.v8i1.41892

Abstract

In the cafe industry, real-time visitor monitoring is a critical challenge for operational optimization. This study develops a visitor counting system based on ultrasonic sensors and Bluetooth communication, designed for cafes in Indonesia. The ultrasonic sensor detects the presence of visitors based on distance, while the data is sent to an Android application via the HC-05 Bluetooth module. With an experimental approach, the system was tested in different scenarios (individual visitors, groups, and walking speed) to evaluate the accuracy. The results show that the sensor is able to identify visitors at a distance of ≤15 cm. Bluetooth integration ensures stable data transmission with a maximum distance of 10 meters. This system provides a cost-effective wireless solution for cafe owners, although further research is needed to overcome the drawbacks in dynamic scenarios.
Rancang Bangun Sistem Penyiraman Tanaman Otomatis Berbasis Raspberry Pi 3 dengan Memanfaatkan Thingspeak dan Interface Android Sebagai Kendali Zikri, Annisa; Yuniarti, Elvan; Lestari, Dewi
Jurnal Fisika Unand Vol 11 No 1 (2022)
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jfu.11.1.44-49.2022

Abstract

Padatnya aktivitas diluar rumah membuat sebagian orang lupa untuk menyiram tanaman sehingga saat kembali ke rumah didapati tanaman telah mati kekeringan. Penelitian ini bertujuan untuk merancang dan membangun sistem penyiraman tanaman otomatis yang dapat dikontrol dari jarak jauh melalui Smartphone Android. Sensor YL-69 digunakan untuk mendeteksi kondisi kelembaban tanah. Apabila kelembaban tanah dibawah batas minimal maka pada tampilan aplikasi Android akan muncul pemberitahuan. Proses penyiraman akan aktif jika Raspberry Pi 3 menerima perintah dari pengguna melalui Smartphone Android. Proses pengiriman serta pembacaan data pada sistem ini diperantarai oleh ThingSpeak. Penelitian ini menggunakan metode eksperimen. Pengujian dilakukan dengan membandingkan keakuratan sensor yang digunakan dengan alat yang sudah beredar dipasaran. Penelitian ini menghasilkan karateristik yang menunjukkan DHT22 memiliki ketelitian sebesar 98.65% dan standar deviasi ±0.14 pada pengukuran temperatur udara. Ketelitian sebesar 98.72% dan standar deviasi ±0.38 untuk pembacaan kelembaban udara. YL-69 memiliki ketelitian rata-rata sebesar 95.22% dan standar deviasi sebesar ±5.4. Terdapat selisih waktu sebesar 1.2 detik pada waktu pengiriman data oleh Raspberry Pi 3 dan waktu penerimaan data oleh ThingSpeak. Sistem ini memiliki kecepatan respon sebesar 2 detik.
Co-Authors Ambran Hartono Azhar, Anugrah Dedi Dedi Dewi Lestari Dewi, Lizky Azka Dinda Sari, Yayang Dwi Nanto, Dwi Fajriah, Nurul Harahap, Try Surya Loua, Lamin Rene Nurlaela, Ai Salsabila Tahta Hirani Putri Saptari, Siti Ahmiatri Saptari, Sitti Ahmiatri Tony Kristiantoro, Tony Zikri, Annisa