Risalah Fisika merupakan jurnal yang mempublikasikan hasil-hasil penelitian dalam bidang fisika secara umum, mencakup Fisika Teoritik, Experimen dan Terapan di berbagai bidang (Astrofisika dan Astronomi, Fisika Inti, Atom dan Molekul, Biofisika, Fisika Zat Mampat, Energi, Fisika Bumi, Fisika Material, Fisika Matematika, Fisika Optik, Fisika Partikel, Fisika Kuantum) dan Fisika Pendidikan. Risalah Fisika is a journal that publishes research results in the field of physics in general, including Theoretical, Experimental and Applied Physics in various fields (Astrophysics and Astronomy, Nuclear, Atomic and Molecular Physics, Biophysics, Compressed State Physics, Energy, Earth Physics, Material Physics, Mathematical Physics, Optical Physics, Particle Physics, Quantum Physics) and Educational Physics.
Faktor Koreksi Ionization Chamber pada Dosimetri Berkas Elektron: Kualitas Berkas, Polaritas, dan Rekombinasi Ion di Berbagai Kondisi Pengukuran
Ionization chamber dosimetry in electron beam radiotherapy required accurate correction for beam quality, polarity effects, and ion recombination. This review examined current evidence on these correction factors under conventional, high dose rate electron, ultra-high dose rate, extended source-to-surface distance, and small-field conditions, with emphasis on recent updates to international electron dosimetry formalisms. Updated Monte Carlo calculations for the beam quality correction factor produced values approximately 0.5% lower than older protocol tabulations, while multicenter experimental data showed that inter-institutional variability remained within the ±2% clinical tolerance. For the polarity correction factor, dose per pulse, electrode spacing, field size, and cable geometry were identified as the main determinants, with cable irradiation producing large apparent polarity corrections in large-field and high dose rate electron beams. For the ion recombination correction factor, conventional two-voltage analysis was reliable only up to approximately 10 mGy per pulse; above this range, empirical logistic models provided more accurate correction estimates. Sub-millimeter electrode spacing and high electric field strength were the most important chamber design parameters for ultra-high dose rate dosimetry. Overall, correction factor uncertainties remained controlled under conventional reference conditions but increased substantially under high dose-per-pulse and non-reference geometries, which current protocols did not adequately cover. These findings supported the need for dedicated dosimetry protocols for high dose rate electron, ultra-high dose rate, extended source-to-surface distance, and small-field electron beam modalities.
Tinjauan Literatur Pengurungan Plasma Secara Magnetik Dalam Sistem Tokamak
Kebutuhan global akan sumber energi bersih dan berkelanjutan mendorong pengembangan teknologi alternatif yang mampu menggantikan ketergantungan pada bahan bakar fosil. Salah satu kandidat paling menjanjikan adalah energi fusi nuklir, khususnya melalui sistem tokamak yang memanfaatkan pengurungan magnetik untuk mempertahankan plasma bersuhu tinggi. Makalah ini meninjau secara komprehensif dasar fisika pengurungan plasma dalam konfigurasi toroidal aksisimetris, mencakup dinamika partikel tunggal, teori guiding-center dan gyrokinetik, serta peran partikel terperangkap dan melintas dalam menentukan transport neoklasik. Selain itu, dibahas pula proses transport dan turbulensi yang menjadi keterbatasan utama kinerja tokamak, termasuk kontribusi drift-wave dan aliran zonal terhadap kehilangan energi. Dari perspektif makroskopik, kesetimbangan dan stabilitas magnetohidrodinamika dianalisis melalui parameter seperti faktor keamanan dan prinsip energi. Interaksi gelombang-partikel, termasuk peredaman Landau dan resonansi siklotron, juga dikaji sebagai mekanisme penting dalam pemanasan plasma dan pembangkitan arus non-induktif. Melalui integrasi berbagai skala fenomena, dari mikroskopik hingga makroskopik, kajian ini menegaskan bahwa pemahaman menyeluruh terhadap fisika plasma merupakan kunci dalam mengoptimalkan performa tokamak dan mewujudkan energi fusi sebagai solusi energi masa depan.
The Role of Hydrothermal Time in Determining the Phase Purity and Compressive Strength of Biogenic Hydroxyapatite from Meretrix meretrix Clam Shell
Biogenic hydroxyapatite (HA) often contains calcium hydroxide [Ca(OH)₂] as a residual unreacted phase. This study investigates the effect of synthesis duration on the phase purity and compressive strength of HA. HA was synthesized from Meretrix meretrix clam shell (MCS) via a hydrothermal method with reaction times of 15, 18, and 21 hours. Phase composition and purity of HA were characterized using X-ray diffraction (XRD). The results showed that at the 21-hour reaction time, the HA phase purity reached 98.85 %, while the residual Ca(OH)₂ content was 1.15 %. Mechanical properties were evaluated using a Universal Testing Machine (UTM), showing that the compressive strength of HA increased with longer synthesis durations. These findings demonstrate that optimizing hydrothermal synthesis time effectively enhances phase purity and compressive strength of HA, while also highlighting the potential of MCS as a sustainable and high-value biogenic source.
Computational Modeling and Visualization of Quantum Wavefunctions in The Particle-in-a-Box and Hydrogen Atom
This study models and visualizes quantum wavefunctions in two fundamental systems-namely the one-dimensional particle-in-a-box and the hydrogen atom-using a computational Python-based approach. The Schrödinger equation is solved analytically to obtain the wavefunctions and probability distributions, which are subsequently visualized in both two and three dimensions. For the particle-in-a-box system, the results demonstrate clear energy quantization, increasing numbers of nodes, and waveform evolution that aligns with theoretical predictions. In the hydrogen atom system, the modeling incorporates the radial and angular components of the wavefunction, producing realistic orbital representations such as 1s, 2p, 3p, and 3d according to the chosen quantum numbers n, l, and m. The resulting visualizations clearly illustrate the relationship between quantum numbers, nodal structure, and electron probability distributions. Overall, the study shows that computational modeling effectively bridges mathematical solutions and physical interpretation, providing a powerful tool for enhancing conceptual understanding in quantum mechanics education.
Microzonation Of Seismic Vulnerability Index Based on Horizontalto Vertical Spectral Ratio Method In Kapanewon Prambanan,Sleman Regency
Prambanan Sub-district, Sleman Regency, is located in the Yogyakarta Basin, which has complex geological characteristics. This area consists of thick sedimentary deposits, making it vulnerable to increased seismic wave amplitude. This geological complexity plays a major role in increasing seismic risk, which occurred during the 2006 Yogyakarta Earthquake, where this area was on the VII MMI intensity scale and experienced quite severe infrastructure damage. Therefore, a study of seismic vulnerability microzonation is needed as a step to mitigate earthquake disaster risk. This study uses the Horizontal to Vertical Spectral Ratio (HVSR) method by comparing the spectrum of horizontal and vertical components of microtremor waves to produce dominant frequency values, amplification factors, and seismic vulnerability indexes. Furthermore, the HVSR curve is inverted using the Particle Swarm Optimization (PSO) method to obtain the average shear wave velocity value up to a depth of 30 meters VS30. The results of the analysis show that the dominant frequency values in the study area range from 0.98 Hz to 17.13 Hz, while the amplification factor is in the range of 1.06 to 11.69. The VS30 value varies from 114 m/s to 726 m/s, and the seismic vulnerability index ranges from 0.18 to 7.46. Geologically, the Madurejo, Sumberharjo, and Bokoharjo Village areas located in the Young Merapi Formation have high seismic vulnerability values. This is due to the dominance of soft soil material and thick sediment layers. In contrast, areas with the Semilir and Kebobutak Formations dominated by hard rocks and hilly topography show lower vulnerability values. Based on these results, areas with high vulnerability levels need to be prioritized in earthquake-resistant infrastructure development planning and sustainable disaster mitigation strategies.
Mapping Ground Acceleration in the Purworejo Region Using the Probabilistic Seismic Hazard Analysis (PSHA) Method with Seismic Data from 1900 to 2024
Purworejo Regency is located in southern Java, directly facing the subduction zone. Its formation is alluvial, making the area vulnerable to seismic hazards. This study aims to map the Peak Ground Acceleration (PGA), Spectral Acceleration (SA), and amplification values in the southern part of Purworejo. PGA values were obtained using the Probabilistic Seismic Hazard Analysis (PSHA) method, while SA was calculated at periods T = 0.2 s and T = 1 s at a 2% exceedance probability over 50 years in both bedrock and surface layers. The data used were earthquake catalog data from the United States Geological Survey (USGS) from 1900 to 2024 with a minimum magnitude of M ≥ 5.0 and a depth of ≤ 300 km. The results show that for bedrock, the PGA value for the Purworejo region is 0.37–0.43 g, SA at T = 0.2 s is 0.79–1.0 g, and SA at T = 1 s is 0.55–0.63 g. The PGA value at the surface is 0.37–0.45 g, the SA at T = 0.2 s is 0.81–1.0 g, and the SA at T = 1 s is 0.55–0.73 g. The calculated amplification values are 1.0–1.03 for PGA and 1.0–1.09 for SA at T = 0.2 s, and 1.0–1.17 for SA at T = 1 s. Among the southern regions of Purworejo showing high PGA, SA, and amplification values are Purwodadi and Ngombol districts. These two areas have higher vulnerability to earthquake hazards compared to surrounding areas.
Development of The Theory of Nuclear Structure from The Perspective of Nuclear Physics
The study of the atomic nucleus's structure is a fundamental aspect of nuclear physics that continues to evolve in tandem with advances in theory, experimentation, and computation. The development of nuclear structure theory does not proceed linearly, but rather through the evolution of various complementary approaches, ranging from experimental foundations to modern theoretical formulations. This study aims to provide a comprehensive overview of the development of nuclear structure theory from a nuclear physics perspective, utilizing a Systematic Literature Review (SLR) approach and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) method. The literature search process was conducted through reputable scientific databases with the inclusion criteria of relevant journal articles published between 2020 and 2025. The results of the study resulted in 13 selected articles representing the stages of development of nuclear structure theory, including experimental foundations, phenomenological models such as the liquid drop model, microscopic approaches through shell models, to modern theories based on many-body, ab initio, and alternative frameworks. The synthesis of findings shows that the development of nuclear structure theory is evolutionary and cumulative, with each approach making specific contributions to explaining the properties and dynamics of atomic nuclei. This study emphasizes the importance of integrating various models and methods in forming a comprehensive understanding of modern nuclear physics.
STEM Integration In Physics Education and Its Influence on Cognitive Skills: A Systematic-Literature Review (2014-2025)
Integration of Science, Technology, Engineering, and Mathematics (STEM) in physics education has become a strategic approach to enhancing students' cognitive skills in response to the demands of the 21st century. This study aims to present a systematic literature review of 20 scientific articles that examine the implementation of STEM- based learning in physics education and its impact on students' cognitive skills. The method employed is a systematic literature review, involving stages of identification, selection, and thematic analysis of articles published between 2015 and 2024. The findings indicate that STEM integration consistently has a positive effect on students' cognitive skills, particularly in critical thinking, problem-solving, conceptual understanding, and higher-order thinking skills (HOTS). Furthermore, the STEM approach promotes learning that is more contextual, collaborative, and oriented toward real-world problem solving. Therefore, the integration of STEM in physics education is recommended as an effective instructional approach to improving the quality of students' cognitive learning outcomes.
Pengukuran Medan Magnet Solenoid Menggunakan Sensor HMC 5883L Berbasis Arduino Uno
Penelitian ini menyelidiki pengukuran medan magnet yang dihasilkan oleh solenoid menggunakan sensor HMC5883L yang terintegrasi dengan mikrokontroler Arduino Uno. Tujuannya adalah untuk mengevaluasi kinerja sensor dalam mencatat perubahan medan magnet pada titik tetap saat arus solenoid bervariasi dari 0 hingga 1,1 A. Metode eksperimental melibatkan kalibrasi sensor, pengumpulan data untuk dua belas variasi arus, dan perbandingan nilai medan magnet yang diukur dengan perhitungan teoritis berdasarkan parameter fisik solenoid. Hasil penelitian menunjukkan bahwa sensor HMC5883L secara akurat mendeteksi perubahan medan magnet pada rentang arus rendah hingga sedang, dengan nilai efektif mengikuti tren linear seperti yang diprediksi oleh teori. Namun, pada arus yang lebih tinggi, medan yang diukur turun tajam dan menyimpang dari harapan teoritis, kemungkinan besar disebabkan oleh keterbatasan sensor, saturasi magnet, dan efek pemanasan di kumparan. Penelitian ini mengkonfirmasi kesesuaian sensor HMC5883L untuk pengukuran medan magnet praktis dalam rentang arus terbatas dan menyoroti perlunya pemilihan sensor yang cermat dan kalibrasi dalam aplikasi medan tinggi.
Kajian Efisiensi Sistem pada Prototype Lumina Drive Integrasi Motor DC dan LED dalam Rangkaian Paralel
Penelitian ini bertujuan untuk mengevaluasi tingkat efisiensi energi pada perangkat Lumina Drive, yaitu sistem yang mengintegrasikan dua motor arus searah (DC) dan dioda pemancar cahaya (LED) dengan satu sumber tegangan dalam konfigurasi rangkaian paralel. Prototipe Lumina Drive dirancang untuk memperlihatkan proses konversi energi listrik dari baterai menuju energi kinetik rotasi pada motor DC dan energi cahaya pada LED. Metode penelitian yang digunakan ialah eksperimen kuantitatif melalui pengukuran tegangan, arus, energi masuk, dan energi keluar pada setiap komponen dengan menggunkan multimeter. Data diperoleh melalui pengujian langsung menggunakan sumber tegangan baterai 9 volt, dua motor DC dan satu unit LED. Hasil pengujian menunjukkan bahwa total energi masuk sistem sebesar 96.12J, sedangkan energi keluaran yang terdiri atas energi kinetik kedua motor DC dan energi listrik pada LED mencapai 9.7201 J J, sehingga menghasilkan efisiensi keseluruhan sebesar 10,11%. Nilai efisiensi ini menunjukkan bahwa sebagian energi masukan berhasil dikonversi menjadi energi berguna, sementara sisanya hilang akibat rugi mekanik, gesekan poros motor, serta resistansi internal rangkaian. Meskipun demikian, Lumina Drive efektif digunakan sebagai media pembelajaran untuk memahami konsep konversi energi listrik menjadi energi kinetik rotasi dan energi cahaya dalam rangkaian paralel. Temuan ini memberikan dasar bagi pengembangan prototipe yang lebih efisien pada penelitian selanjutnya.further research.
Penggunaan Alat Peraga Spring Elasticity IoT Meter (SEIM) untuk Mengukur Periode dan Frekuensi Pegas Berbasis ESP8266 Menggunakan Sensor HC-SR04 dan Blynk
Penelitian ini bertujuan untuk mengetahui validasi, akurasi, dan respon siswa terhadap penggunaan media pembelajaran fisika berupa alat peraga Spring Elasticity IoT Meter (SEIM) untuk mengukur periode dan frekuensi pegas secara real-time dengan variasi massa beban. SEIM dirancang menggunakan mikrokontroler ESP8266, sensor ultrasonik HC-SR04, keypad, dan LCD I2C yang diintegrasikan menggunakan aplikasi Blynk di smartphone sebagai tampilan data berbasis Internet of Things (IoT). Metode yang digunakan adalah R&D dengan model pengembangan ADDIE. Pengujian SEIM melalui validasi ahli materi dan media memiliki nilai rata-rata persentase 86% dengan kriteria sangat layak. Pengukuran tingkat akurasi SEIM terhadap rumus teori dengan massa 0,05 kg, 0,07 kg, 0,09 kg, dan 0,11 kg pada pengukuran periode pegas memiliki rentang akurasi 96-98,21% dan rata-rata error 0,01 s. Pengukuran frekuensi pegas memiliki rentang akurasi 97,62-99,28% dan rata-rata error 0,03 Hz. Respon dari 30 siswa terhadap alat peraga SEIM memiliki nilai rata-rata persentase 86% dengan kreteria sangat setuju.
Optimasi Material Inti Waveguide Optik Berbasis Expanded Polystyrene (EPS) dan Unsaturated Polyester Resin (UPR)
Waveguide digunakan secara luas dalam sistem optik karena strukturnya yang kuat, ringan, dan mampu memandu cahaya dalam bentuk chip. Sebagai material inti waveguide, Unsaturated Polyester Resin (UPR) dan polystyrene (PS) telah banyak diteliti. Namun, UPR menghasilkan rugi daya yang relatif tinggi, yaitu sekitar 7,89 dB hingga 13,85 dB. Sementara itu, waveguide berbahan Expanded Polystyrene (EPS) memiliki rugi daya lebih rendah, namun proses fabrikasi yang lebih lama. Oleh karena itu, dalam penelitian ini, telah dilakukan optimasi material inti waveguide dengan mengkombinasikan EPS dan UPR untuk menurunkan waktu fabrikasi dan rugi daya. Fabrikasi waveguide dilakukan dengan memahat polymethilmethaacrylate (PMMA) sebagai substrat dibagian tengah menggunakan mesin pahat computer numerical control (CNC) dengan ukuran melintang 1×1 mm2. Selanjutnya, bagian PMMA yang telah dipahat diisi dengan material inti. Pada kedua ujung lembar PMMA dipasangkan polymer optical fiber (POF) sebagai media untuk menghubungkan waveguide dengan sumber cahaya dan detektor. Sebagai selubung atas, digunakan PMMA yang tidak dipahat. Enam variasi konsentrasi EPS dan UPR telah digunakan. Karakterisasi dilakukan dengan cara melewatkan cahaya LED berwarna merah dengan panjang gelombang 660 nm ke dalam waveguide. Pengukuran tegangan keluaran pada waveguide dilakukan menggunakan detektor fotodioda yang disambungkan dengan multimeter. ada campuran EPS dan UPR terjadi pergeseran serta penurunan intensitas puncak, dengan munculnya puncak baru di sekitar 1700 cm⁻¹ (C=O) dan 1100–1300 cm⁻¹ (C–O), menandakan interaksi kimia antar material. Korelasi menunjukkan semakin tinggi konsentrasi UPR, waktu pengeringan semakin singkat (r = 0,9767) namun rugi daya meningkat (r = 0,969).
Systematic Literature Review (SLR): Pengembangan Asesmen Formatif untuk Mendukung Pembelajaran Fisika dalam Kerangka Kurikulum Merdeka
Penelitian ini bertujuan untuk meninjau secara sistematis literatur mengenai pengembangan dan penerapan asesmen formatif dalam pembelajaran Fisika di bawah Kerangka Kurikulum Merdeka. Pentingnya asesmen formatif ditekankan dalam Kurikulum Merdeka untuk memantau perkembangan siswa, memberikan umpan balik, dan menyesuaikan strategi pembelajaran guna meningkatkan pemahaman mendalam, berpikir kritis, pemecahan masalah, dan literasi sains dalam Fisika, meskipun implementasinya menghadapi tantangan. Metode Systematic Literature Review (SLR) digunakan untuk mengidentifikasi, menganalisis, dan mensintesis temuan dari studi-studi relevan. Data diperoleh dari Google Scholar dan Emerald Journal, dengan fokus pada 10 artikel yang diterbitkan antara tahun 2021 hingga 2025. Proses seleksi literatur didokumentasikan menggunakan Diagram Alir PRISMA. Tinjauan ini diharapkan dapat memberikan gambaran komprehensif dan landasan bagi praktik asesmen formatif yang efektif dalam pembelajaran Fisika sesuai Kurikulum Merdeka.
Mapping of Land Cover Using Remote Sensing in Papela Village, Rote Timur District in 2021
Land cover mapping with remote sensing has never been done in Papela Village. This land cover mapping can provide information to the Papela village government regarding land cover in Papela village. Since 2021, Papela village has experienced regional expansion. Therefore, in this study, it aims to map the land cover on Rote Island, precisely in Papela village, Rote Ndao Regency before the expansion of the area using remote sensing. The remote sensing data used is a Landsat 8 image recorded in March 2021 which was downloaded from the USGS website. Landsat 8 imagery is classified in a guided manner according to the land cover training area data taken by GPS. The results of this study are in the form of land cover maps in Papela village. From this map, 6 classes of land cover were obtained, namely settlements (22.73 ha), shrubs (56.52 ha), forests and mangroves (39.76 ha), rice fields (31.39 ha), ponds (1.46 ha), and gardens (6.48 ha).
Towards Green Reduction of Reduced Graphene Oxide: A Comparative Study of Hydrazine and Ascorbic Acid Post Modified Hummer's Synthesis
The production of reduced graphene oxide (rGO) traditionally relies on hazardous reducing agents like hydrazine, which poses significant environmental and health risks. This study conducted a comparative analysis of the reduction of graphene oxide (GO), synthesized via a modified Hummer's method, using toxic hydrazine versus a green alternative, ascorbic acid. The resulting rGO from both methods was characterized using X-Ray Diffraction (XRD) and Fourier-Transform Infrared (FTIR) spectroscopy to evaluate structural and chemical changes, while waste profiles and process efficiencies were also compared. The results demonstrated that both hydrazine and ascorbic acid effectively reduced GO, as confirmed by the disappearance of the GO (001) peak and the emergence of the rGO (002) peak in XRD patterns, alongside a significant reduction of oxygen-containing functional groups in FTIR spectra. However, a critical difference was observed in their environmental impact; hydrazine generated a toxic, carcinogenic effluent and caused nitrogen doping, while ascorbic acid produced a benign, non-toxic waste stream. It was concluded that despite challenges such as process optimization and purification, ascorbic acid presents a vastly superior and more sustainable pathway for rGO synthesis for most applications, successfully balancing reduction efficiency with environmental responsibility.
Potential and Mechanism of Plants as Radioprotection Agents in Cancer Therapy: Review
Radiotherapy is a widely used treatment for cancer, yet it can cause harmful side effects due to oxidative stress and DNA damage in healthy tissues. This systematic literature review explores the potential of medical plants as natural radioprotective agents. Twenty plant species were identified, and their bioactive compounds such as flavonoids, polyphenols, saponins, and tannins were shown to exhibit antioxidant, anti-inflammatory, and DNA repair properties. The predominant mechanism of protection involves free radical scavenging. However, non-selective action and the possibility of protecting cancer cells remain major challenges. While in vivo and in vitro studies show promising results, further research is necessary to develop clinically applicable formulations. Natural plant-based agents offer a safer alternative to synthetic radioprotectors, potentially enhancing patient outcomes in radiotherapy.
Radioprotection; Antioxidants; Phytochemicals; Cancer therapy; Oxidative stress
Synthesis of Silica-Based Glass from Quartz Sand and P₂O₅-BaO-Na₂O Compounds Using the Melt-Quenching Technique
This study reports the development of phosphate-based glass materials incorporating quartz sand sourced from Huta Ginjang, North Sumatra, Indonesia, with a specific focus on their potential application as host matrices for rare earth ions in optical amplification systems. Phosphate glasses are recognized for their excellent transparency and chemical stability, making them promising candidates for various optical applications. Quartz sand was collected and subjected to a cleaning process to eliminate impurities, such as dust and organic matter, which may negatively impact the quality of the resulting glass. The purified sand was subsequently ground using a ball mill for 4 h to achieve the desired particle size distribution. The ground quartz was then combined with phosphorus pentoxide (P₂O₅), barium oxide (BaO), and sodium oxide (Na₂O) in the following molar composition: x mol% quartz sand + (60 − x) mol% P₂O₅ + 10 mol% BaO + 30 mol% Na₂O, where x = 0, 2.5, 5, 10, 15, and 20 mol%. The glass batches were melted at 1200 °C for 3 h using the melt-quenching technique. The synthesized glass samples demonstrated good homogeneity and high optical transparency. The physical characteristics of the resulting materials indicate their suitability for use as host matrices in optical devices. Further analysis is required to assess the incorporation efficiency and spectroscopic properties of rare earth dopants within this glass system.
Evaluation of Mendeley Usage in Physics Education Students at Jambi University
This study aims to determine the utilization of the Mendeley application in the scope of Physics Education students at Jambi University where Mendeley is one of the applications that can be used to make it easier for writers to create citations and bibliographies in writing. This study uses a quantitative method that uses numerical data and statistical analysis through surveys to answer research questions. A total of 52 Physics Education students at Jambi University who use Mendeley participated in this study. The data collected was through a Google form in the form of a questionnaire that was submitted online to obtain information from a sample population of Physics Education students. The results of this study indicate that most Physics Education students are active in using Mendeley both in making lab reports and other writing. The use of Mendeley also has many positive impacts on students such as improving the quality of writing and helping to manage references, and can avoid mistakes in compiling bibliographies. Thus Mendeley greatly helps students in efficiency and minimizing errors in writing
Analysis of the Relationship Between Temperature and Extreme Rainfall with Drought and Flood Events in Lampung Province
The extreme temperature and rainfall studied in this study have a clear purpose, namely to identify recurring patterns that occur in a certain time span related to the level of rainfall in a certain region. By analyzing the data, it is hoped that it will be possible to better understand the weather and climate dynamics in the context of the region, as well as to enable the development of more effective adaptation and mitigation strategies against the impacts of climate change. This study uses RClimDex to identify temperature and precipitation data to be observed in the year from 1981-2022. The results show extreme rainfall temperatures in the Lampung Province area if there are no optimal countermeasures, projections of climate conditions in the region in the next 100 years show a tendency to decrease rainfall and increase temperature. With increasingly rare rainfall and significantly rising air temperatures, this has the potential to trigger droughts and fires. But the government also needs to pay attention to the threat of hydrometeorological disasters that can arise due to heavy rainfall.
Effect of Electrodeposition Time on Microstructure, Morphology, and Optical Properties of CIGS Films
Solar cells based on crystalline structured materials such as CIGS (Coper Indium Gallium Selenium) have great potential to replace limited fossil energy sources. Optimization of CIGS solar cells was carried out using the electrodeposition method. Electrodeposition is carried out by dipping ITO and platinum substrate electrodes into a CIGS solution with a voltage of -2V for 5-15 minutes. Samples were characterized using XRD, SEM, and UV-Vis. Based on the XRD characterization results, the length of electrodeposition time increases the intensity in the hkl 211 and 112 planes, which indicates better CIGS crystallinity. The results of SEM characterization revealed that the CIGS particle size on the substrate surface can be deposited evenly, with the particle size getting smaller, namely 0.76, 0.68, and 0.32 μm. The SEM analysis also obtained the porosity values, namely 59.28, 64.05, and 68.34. The length of time for CIGS electrodeposition does not significantly affect the absorbance of the film in the UV light range, namely 300 - 350 nm. However, the CIGS band gap becomes larger, namely 3.66, 3.71, and 3.73 eV.
Caleso (Cassava Leaf Soap): Cassava Leaf Extract Herbal Soap as a Solution to Skin Problems
Skin health is an important thing to always pay attention to. A person's lack of maintaining healthy skin can result in skin problems such as wounds and acne. Wounds and acne on the skin can be caused by the activity of Staphylococcus aureus bacteria. One effective way to treat acne and wounds is to use soap. Researchers had the idea to make herbal soap from cassava leaf extract (Manihot esculenta). So far, cassava leaves have not been used optimally. In fact, based on research, cassava leaves contain vitamin C, flavonoids, saponins and triterpenoids which are believed to have antibacterial activity and speed up the wound healing process. The aim of this research was to determine the effect of antiseptic herbal soap from cassava leaf extract (Manihot esculenta) on acne and skin wounds caused by Staphylococcus aureus bacteria. The type of research used is experimental research. The research was carried out by carrying out several tests, namely organoleptic tests, homogeneity tests, foam height tests, pH tests, and irritation tests. The research results show that cassava leaves can be used to make soap that can treat skin problems such as wounds and acne. Cassava leaf extract herbal soap is safe to use for Indonesian people who have skin problems such as acne and wounds because it contains natural ingredients that are suitable for use on all skin types.
Development of Student Worksheet Assisted by Phyphox Application on Harmonic Vibration Material
This study aims to develop student worksheets assisted by the Phyphox application on the material of Harmonic Oscillations in Springs. This study uses a 4D model consisting of 4 main stages: define, design, develop, and disseminate. The results of the designed worksheets have been reviewed by 2 physics education experts, and are considered suitable for use to support classroom learning. The trial was conducted in one class consisting of 31 students. The results of the trial showed an increase in learning outcomes after students participated in learning with the worksheets assisted by Phyphox that was developed. In addition, students also gave a good response to the use of worksheets assisted by Phyphox. Thus, the worksheets that were developed have the potential to be used in physics learning widely.
Preliminary Study of Ultrasonic Generator Design Based on Microcontroller
Ultrasonic waves have been used in various fields such as cleaning, purification, and homogenization of particles by cavitation in liquid mediums. Cavitation is the formation, growth, and destruction of micro-sized gas bubbles. In this study, an ultrasonic generator based on an Arduino microcontroller has been designed. This research aims to produce square waves by utilizing the PWM method from Arduino Uno, where the frequency and duty cycle generated can be changed according to user needs. The method used in this study is an experimental method with components consisting of Arduino Uno, Mono Digital Audio Amplifier TPA3118, Power Supply 12 V, and Ultrasonic Transducer 40 kHz 60 W. Frequency and duty cycle are regulated using push buttons. The Arduino wave output will be amplified using an amplifier which is then used to produce the ultrasonic transducer. In the test of the generators made, several variations of duty cycles of 15%, 25%, 50%, 75%, and 85% were used. The result of this study is that ultrasonic generators can produce output frequencies of up to 58 kHz with error values of 0.83%, 0.97%, 0.92%, 0.70%, and 15% for each duty cycle.
The Effect of Graphite as an Electrode Material towards Supercapacitor Discharging Time
This study aimed to 1) make a graphite-based supercapacitor, 2) characterize the graphite prepared, and 3) determine the effect of graphite mass as an electrode material towards the supercapacitor discharging time. This study consisted of three stages, namely: i) preparation of the graphite-based electrode material, ii) characterization of the graphite prepared, and iii) measurement of the supercapacitor discharging time with varying graphite mass. The characterizations of the graphite were carried out using an ultraviolet-visible (UV-Vis) spectrophotometer, X-ray diffraction (XRD), and particle size analyzer (PSA). The electrode material is made of graphite, epoxy, and aquadest. Variations were made on the graphite mass deposited on the aluminum plate, namely, 1 g, 2 g, 4 g, 6 g, 8 g, and 0 g as a negative control. The results showed that the graphite was well deposited on the aluminum plate. The results of the UV-Vis characterization indicated that the graphite had an absorption peak at a wavelength of 301 nm. The XRD test showed the crystalline structure of the graphite with a sharp peak at 2q of 26o. The PSA test showed that the dominant particle size distribution was 687 nm. The capacitors were given a voltage of 6 V for 1 minute. The measurement results showed that the discharging time increased as the amount of deposited graphite mass was increased. The electrode material with a mass of 8 g showed the longest discharging time, which was 12,000 seconds. The capacitors that were not deposited with graphite showed the shortest discharge time of 48 seconds after the power supply voltage was released.
Design of an Inclined Plane Experiment Tool Using E18-D80NK Infrared Proximity and MPU6050 Accelerometer Sensors: An IoT-Based Approach
Electronics plays an important role in science, especially in the development of laboratory equipment technology in schools, which is the main pillar in education. Current laboratory equipment still relies on manual operation, reducing measurement efficiency and accuracy. This research focuses on developing an IoT-based inclined plane measurement system that can display results digitally. The system utilizes IoT-based E18-D0NK proximity sensor and MPU6050 accelerometer to ensure more precise and efficient measurements. The main objective of this research is to establish the performance specifications and system design of the inclined plane experimental tool. This research is an engineering research that measures the inclined plane by the object launch method, using both direct and indirect approaches. Direct measurements were taken via a mobile phone screen, while indirect measurements assessed the accuracy and precision of the digital system compared to conventional methods. The data was analyzed with statistical and tabular analysis to provide an overview of the system's performance. The system used proximity sensors to start stop the movement and accelerometers to calculate the tilt angle. The MPU6050 sensor showed an average accuracy of 99.22% and an average precision of 0.991. This tool shows an average accuracy of 98.83% with an accuracy of 0.996.