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Visualization of Microseismic Processing by Coding with GNU Octave Purnama, Aditya Yoga; Nurhanafi, Kholis; Susanti, Susanti; Wibowo, Nugroho Budi
Navigation Physics : Journal of Physics Education Vol 7, No 1 (2025): Navigation Physics : Journal of Physics Education Vol. 7 No. 1 Tahun 2025
Publisher : UNIVERSITAS INDRAPRASTA PGRI

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30998/npjpe.v7i1.3965

Abstract

The use of software in the field of geophysics is often limited to the instantaneous use of interfaces without a deep understanding of the computational processes behind them. This leads to limitations in data interpretation and the development of new methods. To address this issue, it is necessary to explicitly visualize the data processing process through programming in order to strengthen computational thinking skills, which are one of the important competencies of the 21st century. This study aims to visualize the microseismic data processing process using programming in GNU Octave software. The method used is a simulation of microseismic data processing based on the HVSR (Horizontal to Vertical Spectral Ratio) approach, with field data collected from the Yogyakarta area. The processing is carried out by building a programming script in GNU Octave, the results of which are then compared with the Geopsy software as a verification tool. The research results indicate that data processing visualization using the HVSR method through GNU Octave can be performed effectively, and the results exhibit high consistency with the output from Geopsy. The dominant frequency on both curves is the same at a frequency of 1.59 Hz. In addition to the dominant frequency, the HVSR curve shape of both software also shows a similar trend pattern in the mid to high frequency range (around 2–10 Hz), where the amplification value decreases gradually. This demonstrates the accuracy of the developed script and proves that this approach can serve as an educational tool for understanding the functioning of geophysical software in a more transparent and in-depth manner. Programming with GNU Octave can be used as an efficient and accurate geophysical analysis tool. This provides opportunities for users, especially in academic environments with limited access to commercial software.
Exploring The Influence of Electrode Material on Electrical Impedance Spectroscopy: A Comparative Analysis Ahmad Zarkasi; Mohammad Asrul; Kholis Nurhanafi; Rahmawati Munir; Amirin Kusmiran; Kormil Saputra
Frontier Advances in Applied Science and Engineering Vol. 2 No. 2 (2024)
Publisher : Tinta Emas Publisher

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.59535/faase.v2i2.279

Abstract

Electrodes play a crucial role in impedance measurements using the EIS method. This study undertook a comparative analysis of impedance measurement outcomes using aluminum, iron, stainless steel, copper, and tin electrodes with mineral water and distilled water as the measurement objects. The impedance Bode plots for mineral water and distilled water showed similar trends across all electrodes, while the phase difference trends varied. In this experiment, copper electrodes emerge as the preferred choice due to their consistently low impedance, particularly at higher frequencies, and their stable phase difference patterns. Additionally, copper electrodes showed superior stability up to 25 kHz, while tin electrodes remained stable up to 50 kHz, albeit valid only from a frequency of 100 Hz. The varying impedance and phase difference in mineral water measurements align with the Warburg impedance circuit, due to the presence of more complex capacitive and inductive elements. Furthermore, measurements with distilled water showed a uniform Bode plot pattern of both impedance and phase difference across all electrodes, making the Randles circuit approach the most appropriate choice in this case. Overall, all electrode types exhibited distinct characteristics.
EARTHQUAKE VULNERABILITY MAPPING BASED ON MICROSEISMIC MEASUREMENTS IN THE CAMPUS AREA OF UNIVERSITAS SARJANAWIYATA TAMANSISWA YOGYAKARTA Purnama, Aditya Yoga; Nurhanafi, Kholis; Susanti, Susanti; Wibowo, Nugroho Budi; Perdhana, Radhitya
JGE (Jurnal Geofisika Eksplorasi) Vol. 11 No. 2 (2025)
Publisher : Engineering Faculty Universitas Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jge.v11i2.486

Abstract

Building damage caused by earthquakes is more prevalent in the sedimentary areas of Yogyakarta City compared to the hilly regions of Wonosari and Kulonprogo, which have harder soil layers. The campus of Universitas Sarjanawiyata Tamansiswa (UST) is one of the campuses located in Yogyakarta City, where the regional geology is dominated by the Merapi Young Volcanic Deposits Formation. The UST campus area is vulnerable to earthquakes due to its proximity to an active seismic zone, making earthquake vulnerability mapping based on microseismic data an important necessity to support disaster mitigation efforts. The microseismic method was used in this study, while data analysis employed the Horizontal-to-Vertical Spectral Ratio (HVSR). Microseismic measurements were chosen because they have the advantage of not damaging the surface conditions of the ground, thus preserving the environment, and are easy to use in urban areas. The research method stages include survey design, field data collection, data processing and interpretation, and the creation of earthquake vulnerability maps. Data points were collected from 7 locations covering the Universitas Sarjanawiyata Tamansiswa campus area. The research results indicate that the study area has a dominant frequency value ranging from 1.10 to 2.74 Hz. Meanwhile, the amplification value ranges from 1.25 to 2.2. The sediment thickness of the study area ranges from 32 to 79 meters. The Seismic Vulnerability Index (Kg) of the study area ranges from 0.57 to 4 on a low to high scale. Based on the dominant frequency values, amplification, and seismic vulnerability index, the areas of the UST campus that are more vulnerable to earthquakes are the northern, eastern, and central parts, while the southern part is relatively safer.
Identifikasi lapisan sedimen kawasan sungai bawah tanah Bribin Gunung Kidul menggunakan metode mikrotremor horizontal to vertical spectral ratio (HVSR) Melyyanti, Meli; Nur Azis, Khafidh; Nurhanafi, Kholis
Jurnal Penelitian Saintek Vol 30, No 2 (2025)
Publisher : Universitas Negeri Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21831/jps.v30i2.89754

Abstract

Penelitian ini bertujuan untuk menentukan dan menganalisis kondisi geologi berdasarkan nilai frekuensi dominan (fo) dan faktor amplifikasi (Ao), menentukan lapisan sedimen berdasarkan nilai vs, serta menginterpretasi ketebalan sedimen berdasarkan ground profiles kecepatan gelombang geser dengan metode ellipcity curve dikawasan Sungai Bawah Tanah Bribin, Gunungkidul. Penelitian ini menghasilkan nilai frekuensi dominan (fo) berkisar antara 2,07 s.d 14,9 Hz dimana nilai frekuensi rendah (<2,5 Hz) yang dibuktikan adanya batuan gamping, sedangkan nilai amplifikasi (Ao) berkisar antara 1,42 hingga 3,81 yang sebagian besar berada pada zona sedang dan zona tinggi, dengan lapisan permukaan yang tipis sekitar 5 hingga 10 meter. nilai ketebalan sedimen di sisi utara sampai tengah daerah penelitian tergolong cukup tebal sedangkan sisi selatan daerah penelitian ketebalan sedimennya tipis karena berada pada sekitar aliran Sungai Bawah Tanah dan di dominasi oleh kawasan pegunungan karst.
IMPEDANCE ANALYSIS FOR FOUR TYPES OF MINERAL WATER AND AQUADES USING ELECTRICAL IMPEDANCE SPECTROSCOPY (EIS) AT FREQUENCIES OF 1 Hz - 50 kHz Wulandari, Darmawati; Zarkasi, Ahmad; Nurhanafi, Kholis
Indonesian Physical Review Vol. 7 No. 1 (2024)
Publisher : Universitas Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29303/ipr.v7i1.269

Abstract

The Electrical Impedance Spectroscopy (EIS) method can be used to identify minerals in mineral water. The EIS method measures the impedance of a material by injecting alternating current in a certain frequency range, which is non-invasive and non-destructive. This study aims to analyze the impedance of mineral water and aquades based on the influence of the dissolved content using EIS equipment that provides flexibility in adjusting the desired frequency spectrum. The study used a frequency range from 1 Hz to 50 kHz with a four-electrode configuration. The measurement graph results were analyzed using Bode graph with impedance plot and phase shift angle to determine the impedance characteristics of mineral water. Equivalent circuit modeling helped to identify the electrochemical properties of materials such as the Warburg circuit, Constant Phase Element (CPE), and Randles circuit. The results show that the aquades has a higher impedance compared to the four mineral waters. Additionally, the four mineral waters exhibit varying impedances, attributed to their respective mineral content. Mineral water is characterized by an impedance that is dominated by Warburg impedance (Zw) at low frequencies, charge transfer resistance (Rct) and double layer capacitance (Cdl) at middle frequencies, and electrolyte resistance at high frequencies. However, the impedance of aquades dominated by electrolyte resistance (Re) at low frequency and Re+Rct at high frequency.
A GUI-BASED DATA ACQUISITION SYSTEM FOR EIT USING TWO CURRENT INJECTION METHODS Zarkasi, Ahmad; Hananda Putra, Muhammad Fauzan; Natalisanto, Adrianus Inu; Nurhanafi, Kholis; Hidayatullah, Muhammad; Kusmiran, Amirin; Nuraidha, Amalia C
Indonesian Physical Review Vol. 7 No. 3 (2024)
Publisher : Universitas Mataram

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29303/ipr.v7i3.356

Abstract

The current injection method played an essential role in the data quality of impedance measurement using the electrical impedance tomography (EIT) technique. Previous studies have largely utilized only a single current injection method with limited interface access, which restricts the effectiveness of EIT systems. In this paper, a graphical user interface (GUI)-based data acquisition system was designed to improve user interaction and optimize the control system. The system was equipped with multiple current injection methods, allowing researchers to choose which method to use in the measurement process. The designed hardware comprises a V-to-I converter circuit, multiplexer, electrodes, peak detector, and filter circuit. Testing results indicate that the V to I converter circuit has an average peak difference between voltage and current of 4.86% and an average error of 0.69% in the peak detector circuit. The multiplexer circuit switches quickly and consistently, while the filter circuit remains stable at the 50 kHz frequency used in this study. These results demonstrate that the designed circuits perform adequately and effectively, ensuring reliable and accurate measurements.  Additionally, the data acquisition software, presented as a GUI, effectively facilitates the selection of current injection methods and the display of boundary data simulation (BDS) on the object. This is demonstrated by the spatial inhomogeneity patterns visible through BDS in both the adjacent and opposite methods
X-ray Absorption Near Edge Structure (XANES) Spectrum Interpretation for LiFePO4-Silicon Doped Cathode Material Intifadhah, Sahara Hamas; Nurhanafi, Kholis; Astuti, Fahmi; Munir, Rahmawati; Hamdani, Dadan; Darminto, Darminto
Jurnal Fisika Unand Vol 12 No 3 (2023)
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jfu.12.3.348-354.2023

Abstract

LiFePO4-Silicon doped has been widely developed as a battery cathode material. Due to the doping of silicon atoms, this study aims to determine the peak energy (E0), oxidation state and percentage of component composition for Fe K-edge. The experimental sample used are LFP Si-0%, LFP Si-1%, LFP Si-3% and LFP Si-6%. These samples were characterized using XAS (X-ray Absorption Spectroscopy). XANES spectrum showed the peak energy of Pre-edge area is 7113.08 – 7114.49 eV. The oxidation state of Fe atoms were increased and tend to be Fe3+ than Fe2+. Moreover, Linear Combination Fitting (LCF) used to determine the ratio composition FeO/Fe2O3 in experimental samples. The ratio composition indicated Fe atom is multivalent, when the percentage of silicon-doped increases, the ratio of Fe3+ increased.It has been found that the presence of silicon atoms in the LiFePO4 structure has an effect in electronic structure.
Analisis Pergerakan Partikel terhadap Rekaman Mikrotremor di Permukaan Sungai Bawah Tanah Bribin, Kawasan Karst Gunung Sewu Nurhanafi, Kholis; Zarkasi, Ahmad; Intifadhah, Sahara Hamas; Wibowo, Nugroho Budi; Purnama, Aditya Yoga
Jurnal Fisika Unand Vol 12 No 3 (2023)
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jfu.12.3.471-478.2023

Abstract

Microtremor has been widely used to determine soil characteristics and dynamics. In this research, particle motion analysis was conducted on 15 microtremor data recordings around the surface of the Bribin Underground River in the Gunungsewu Karst Area. Spectrum analysis was conducted as a basis for determining the frequency range for the particle motion analysis process. Particle motion analysis was only carried out on the horizontal component of the microtremor signal which is expected to provide a representation of the river flow path. The results of particle motion analysis of microtremor recordings in the surface area of the Bribin Underground River show that there are only two points that have a motion-resultant oriented to certain direction, which is perpendicular to the river channel.The points are A4 and B4 which are located in the eastern part of the river flow path.
APLIKASI SENSOR MICRO ELECTRO MECHANICAL SYSTEM (MEMS) ACCELEROMETER BERBASIS IOT DALAM PENGUKURAN PERCEPATAN MAKSIMUM GETARAN STRUKTUR JEMBATAN Rahayu, Rafika Ade; Nurhanafi, Kholis; Syahrir, Syahrir; Zarkasi, Ahmad
Jurnal Informatika dan Teknik Elektro Terapan Vol. 12 No. 2 (2024)
Publisher : Universitas Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jitet.v12i2.4134

Abstract

Alat ukur getaran dengan sensor Micro Electro Mechanical System (MEMS) berbasis Internet of Things (IoT) merupakan alat yang dapat diaplikasikan pada pengukuran nilai percepatan maksimum getaran struktur jembatan. Tujuan penelitian ini adalah untuk merancang alat ukur getaran dengan sensor MEMS berbasis IoT dengan harga yang relatif rendah dan mengukur standar deviasi pada alat ukur tersebut. Pada penelitian ini alat ukur dibuat dengan sensor MEMS tipe ADXL345 yang dihubungkan dengan mikrokontroler NodeMCU Esp8266 lalu diprogram pada interface Arduino IDE agar dapat terhubung dengan platform IoT Blynk. Sistem alat ukur yang dirancang dapat merekam data pada Cloud Blynk dengan nilai sampling 1 Hz. Nilai standard deviasi pada 3 titik pengukuran jembatan tiap sumbunya yaitu: pada titik 1 dengan sumbu x, y, dan z secara berturut-turut sebesar 0.0137 g, 0.0163 g, 0.0228 g; titik 2 sumbu x, y, z secara berturut-turut sebesar 0.0139 g, 0.0195 g, 0.0299 g; titik 3 sumbu x, y, z secara berturut-turut sebesar 0.0139 g, 0.0285 g, 0.0313 g.