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All Journal POSITRON Komunikasi Fisika Indonesia Spektra: Jurnal Fisika dan Aplikasinya Unri Conference Series: Community Engagement Journal of Technomaterial Physics Science, Technology, and Communication Journal
Rini, Ari Sulistyo
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Aerospace Engineering Humanities Astronomy Civil Engineering, Building, Construction & Architecture Computer Science & IT Control & Systems Engineering Earth & Planetary Sciences Electrical & Electronics Engineering Energy Engineering Materials Science & Nanotechnology Physics

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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.
Biosynthesis of Zinc Oxide Powder Using Sandoricum koetjape Peel Extract at Various Annealing Temperature Rini, Ari Sulistyo; Hidayanti, Nurul; Rati, Yolanda
POSITRON Vol 11, No 2 (2021): Vol. 11 No. 2 Edition
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam, Univetsitas Tanjungpura

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (487.835 KB) | DOI: 10.26418/positron.v11i2.49699

Abstract

Zinc oxide (ZnO) synthesized with natural reductants has attracted the attention of researchers because it is environmentally friendly and non-toxic. In this study, ZnO was prepared using Sandoricum koetjape (S. koetjape) peel extract. An aqueous extract of S. koetjape peel was used as biological reduction agent for the synthesis of ZnO from zinc nitrate hexahydrate. The ZnO powder obtained was annealed at different temperatures i.e, 300°C, 400°C, and 500°C for 1 hour. Structural, morphological, optical properties, and functional groups of samples were analyzed using X-Ray Diffraction, Scanning Electron Microscopy, UV-Vis Spectroscopy, and Fourier Transform Infrared Spectroscopy, respectively. The X-ray diffraction pattern shows that pure hexagonal wurtzite structure of ZnO particles can be achieved after annealing. The crystal size has also increased with increasing annealing temperature. SEM photo demonstrates the transformation of ZnO particle from spherical to microflower due to annealing. The widest absorption peaks in the UV-Vis spectrum was occurred after annealing at 500°C. The bandgap energy of ZnO increases after annealing from 3.08 eV to 3.20 eV. The FT-IR analysis confirms O-H functional group from extract has been decomposed due to the annealing process. Based on this study, biosynthesized ZnO using Sandoricum koetjape peel extract requires annealing process to improve the purity, enhance the light absorbance and change the microstructure of ZnO.
CHARACTERIZATION OF ENERGY BAND GAP THIN FILM BaTiO3 – BaZr0.5Ti0.5O3 USING DIFUSION REFLECTANCE SPECTROSCOPY (DRS) METHOD Dewi, Rahmi; Manalu, Wesly Arianto; Asrinaldo, Brian Noval; Rini, Ari Sulistyo; Yanuar, Yanuar
Spektra: Jurnal Fisika dan Aplikasinya Vol. 8 No. 1 (2023): SPEKTRA: Jurnal Fisika dan Aplikasinya, Volume 8 Issue 1, April 2023
Publisher : Program Studi Fisika Universitas Negeri Jakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21009/SPEKTRA.081.02

Abstract

Ferroelectric material is a dielectric material that has a high dielectric constant value so that it can be made in the form of thin films. Its application is based on electro-optical properties, one of which is the infrared thermal switch. This paper aims to determine the bandgap energy (Eg) of a 0.3BaTiO3 – 0.7BaZr0.5Ti0.5O3 thin film. The 0.3BaTiO3 – 0.7BaZr0.5Ti0.5O3 thin film is a semiconductor material with the valence band and conduction band separated by an energy bandgap (Eg). Thin films of 0.3BaTiO3 – 0.7BaZr0.5Ti0.5O3 were grown on FTO substrates using the sol-gel method. The films of 0.3BaTiO3 – 0.7BaZr0.5Ti0.5O3 were annealed at different temperatures of 700°C, 750°C and 800°C within 1 hour. Characterization was carried out using Ultra Violet Visible (UV-Vis) spectroscopy to determine Eg using the Diffusion Reflectance Spectroscopy (DRS) method. The DRS method was found to be better for solid materials considering the scattering component. The UV-Vis characterization results show that an increase in annealing temperature causes a decrease in Eg. For example the values ​​at 700°C, 750°C and 800°C are 3.5 ± 0.01 eV; 3.3±0.01 eV and 3.2±0.01 eV. The decrease in Eg is related to the diffusion of Barium Titanate (BaTiO3) ions into the Barium Zirconium Titanate (BZT) lattice forming a new sub-gap which in turn gives BT-BZT the ability to absorb lower light. Lower light absorption means more capable optics for multilayer systems.
Diffraction Pattern Simulation of Crystal Structure towards the Ionic Radius Changes Via Vesta Program Rini, Ari Sulistyo
Journal of Technomaterial Physics Vol. 1 No. 2 (2019): Journal of Technomaterial Physics
Publisher : Talenta Publisher

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32734/jotp.v1i2.1288

Abstract

The Simulations of X-ray diffraction patterns of MgO, BaO and ZnS ceramics were successfully performed by VESTA program, based on the crystal structures visualization. The aim of this research was to obtain the relationship between ionic radius to the diffraction pattern. The X-ray diffraction pattern was generated from visualization of the crystal structure. The crystal structure information was obtained from JCPDS data which contained lattice parameter, atomic coordinate and the space group. The X-ray diffraction pattern parameters which are taken into account in this research are diffraction angle of 2 Theta and Intensity. The results indicated that the peak position and intensity of the diffraction pattern are influenced by ionic radius of the cations. Structural transformation was also detected from this simulation.
Enhancing rural teacher competence in Meranti Islands Regency high school basic physics practical curriculum Saktioto, Saktioto; Defrianto, Defrianto; Rini, Ari Sulistyo; Irawan, Dedi; Agrina, Agrina; Anita, Sofia; Soerbakti, Yan; Rabin, Mohammed Fisal
Indonesian Physics Communication Vol 21, No 3 (2024)
Publisher : Universitas Riau

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31258/jkfi.21.3.%p

Abstract

Teacher competency standards serve as benchmarks that can be utilised to assess the attributes deemed essential for professional competence in educators. Educators play a crucial and strategic role in the pursuit of national development objectives, particularly within the realm of education. However, the objective of education appears to be a reduction in competency standards at the conclusion of each academic year for specific subjects, particularly in the realm of science and Basic Physics. Consequently, this initiative seeks to inspire educators and students in secondary education to enhance their understanding of the educational process by engaging in the study of science, specifically Basic Physics, utilising appropriate tools and resources. The suggested mode of engagement involves the processes of instruction and education within secondary educational institutions across the Meranti Islands Regency, encompassing SMA, MAN, MTs, and SMP levels. This activity further offers insights into experiments and demonstration tools for educators in the realm of science and Basic Physics, facilitating a comprehension of concepts that range from simple to intricate natural phenomena through accessible demonstration media designed for practical application. In this manner, educators are anticipated to exhibit motivation and enthusiasm throughout the learning process, accompanied by a thorough and nuanced comprehension of the subject matter. To enhance teacher competency standards significantly, ensuring they become more qualified and professional.
Performance analysis of metamaterial antennas based on variations in combination and radius of hexagonal SRR Soerbakti, Yan; Defrianto, Defrianto; Rini, Ari Sulistyo; Asyana, Vepy
Science, Technology and Communication Journal Vol. 4 No. 1 (2023): SINTECHCOM Journal (October 2023)
Publisher : Lembaga Studi Pendidikan and Rekayasa Alam Riau

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.59190/stc.v4i1.250

Abstract

The low antenna performance is a concern for researchers to overcome in modern technology. As an effort to overcome this problem, the application of the metamaterial structure to the antenna was carried out to increase the antenna parameters. This study aims to analyze the effect of antenna performance due to the influence of variations in the combination and radius of the SRR hexagonal metamaterial. The research was conducted in a simulation, starting with designing the antenna structure with the metamaterial of two rings into a resonator with a radius variation of 2.5 mm and 2.7 mm, then combining one to four hexagonal SRRs. The results showed that the highest antenna performance was obtained from a combination of four hexagonal SRRs for a radius of 2.7 mm with parameter values in the form of return loss -38.95 dB, a bandwidth of 7.88 GHz at a working frequency of 1.12 – 9.00 GHz and a gain of 5.92 dBi.
Potential multi-detection manifestation of ultra-sensitive sensors based on ZnO thin films and metamaterials Defrianto, Defrianto; Soerbakti, Yan; Saktioto, Saktioto; Rini, Ari Sulistyo; Fadhali, Mohammed; Yupapin, Preecha
Science, Technology and Communication Journal Vol. 5 No. 1 (2024): SINTECHCOM Journal (October 2024)
Publisher : Lembaga Studi Pendidikan and Rekayasa Alam Riau

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.59190/stc.v5i1.265

Abstract

This study aims to observe the ability of a thin layer of zinc oxide (ZnO) which is applied to sensor technology. Currently, the low detection limit of the sensor is a problem in its use. Metamaterials offer resonant properties in increasing sensitivity, but their performance is still below the current high modern technology. The high engineering properties of metamaterials provide opportunities for realizing renewable metamaterials. ZnO thin layer semiconductor material as a transparent conductive oxide can provide a wide detection potential. The ability of ZnO thin films to be adapted to metamaterial sensors can be further investigated and improved for the future.
Intensifikasi Kompetensi Guru Desa dalam Penguatan Kurikulum Praktikum Fisika Dasar di Tingkat Sekolah Menengah se-Kabupaten Kepulauan Meranti Saktioto, Saktioto; Defrianto, Defrianto; Rini, Ari Sulistyo; Irawan, Dedi; Agrina, Agrina; Anita, Sofia; Soerbakti, Yan; Rabin, Mohammed Fisal
Unri Conference Series: Community Engagement Vol 6 (2024): Seminar Nasional Pemberdayaan Masyarakat
Publisher : Lembaga Penelitian dan Pengabdian kepada Masyarakat Universitas Riau

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31258/unricsce.6.766-771

Abstract

Teacher competency standards are indicators that can be used as a measure of teacher characteristics that are considered professionally competent. Teachers have a very strategic role in efforts to realize national development goals, especially in the field of education. However, the goal of education is to experience a decline in competency standards at the end of each year for certain subjects, especially science / Basic Physics. Therefore, this service aims to motivate educators and students at the secondary school level to raise awareness of the education process through the practice of learning science / Basic Physics using adequate equipment and materials. The proposed form of activity is in the form of teaching and learning in secondary schools throughout the Meranti Islands Regency including SMA, MAN, and MTs, and SMP levels. In addition, this activity also provides guidance on experiments and demonstration tools for science / Basic Physics teachers regarding understanding concepts from simple to complex natural phenomena through simple demonstration media for practical tools. That way, teachers are expected to be motivated and enthusiastic in the learning process with a good and comprehensive understanding of the material. So that it can increase teacher competency standards intensively to be more qualified and professional.
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.
Argon plasma ionization in thermodynamic equilibrium with continuity equation Kasri, Anshori; Saktioto, Saktioto; Farma, Rakhmawati; Rini, Ari Sulistyo; Erwin, Erwin; Awitdrus, Awitdrus
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.v5i3.318

Abstract

Local thermodynamic equilibrium is a foundational concept in plasma physics and heat transfer, describing a state where each small region of a system can be treated as if it is in thermodynamic equilibrium, even if the whole system is not. However, achieving accurately perfect thermodynamic equilibrium conditions in real-experiments is often challenging. It often struggles for understanding phenomena like excited states or specific Arrhenius-driven reactions. As a result, the advantages of plasma modeling with simplifications can sometimes overshadow the disadvantages of experiments. This study simulated the ionization process of argon plasma using the 4th order Runge-Kutta numerical method. The simulation, initiated with initial densities before the simulation is run, each of them is electrons 2.6 × 1018 m-3, neutral argon (Ar) 2.6 × 1018 m-3, positive argon ions (Ar+) 2.6 × 1018 m-3, and positive diatomic argon ions (Ar2+) 2.6 × 1018 m-3, successfully obtained reaction rate equilibrium data at the 625th iteration. The final densities observed were 2.46 × 1018 m-3 for electrons, 2.27 × 1018 m-3 for neutral argon, 6.4 × 1015 m-3 for Ar+, and 4.34 × 1017 m-3 for Ar2+. These results show the equilibrium reaction rate in argon plasma which provides information that density of electron and Ar+ species show a decreasing trend while density of Ar and Ar2+ species shows an increasing trend which are the result of ionization and recombination processes in the entire plasma system.
Co-Authors Agrina, Agrina Aminnurdin, Dikri Asrinaldo, Brian Noval Asyana, Vepy Awitdrus Awitdrus, Awitdrus dedi irawan Defrianto Defrianto Erwin Erwin Fadhali, Mohammed Hidayanti, Nurul Kasri, Anshori Lazuardi Umar Manalu, Wesly Arianto Noferdi, Muhammad Deri Rabiah Rabiah Rabin, Mohammed Fisal Rahmi Dewi Rahmondia N. Setiadi Rakhmawati Farma Rati, Yolanda Rosandi, Vira Annisa Saktioto Saktioto Simatupang, Mediniah Putri Soerbakti, Yan Sofia Anita Tengku Emrinaldi Tetty Marta Linda Yanuar Hamzah Yanuar Yanuar, Yanuar Yupapin, Preecha