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Experimental evaluation of framed and frameless 100 Wp monocrystalline photovoltaic modules under tropical climatic conditions
No full textPhotovoltaic (PV) module performance in tropical climates is strongly affected by high operating temperatures, which reduce voltage and efficiency. Mechanical design features, such as the use of an aluminum frame, influence heat dissipation and may cause different thermal and electrical responses in real outdoor conditions. This study compares the performance of framed and frameless 100 Wp monocrystalline PV modules tested simultaneously in Yogyakarta, Indonesia. Hourly measurements of solar irradiance, module temperature, voltage, current, and power were collected from 07:00 to 17:00 to analyze temperature behavior, power output, and energy yield. The framed module operated approximately 2-3°C cooler during peak irradiance, resulting in more stable voltage and slightly higher instantaneous power output. In contrast, the frameless module produced a slightly higher total daily energy of 74 Wh, compared to 72 Wh for the framed module, due to its faster thermal response during morning and afternoon periods. All experimental trends aligned with established temperature-power coefficients for monocrystalline silicon modules. These findings demonstrate that frame design plays a meaningful role in thermal regulation and overall performance under tropical conditions, providing practical guidance for selecting PV modules in hot and humid environments
Mitigating heavy metal contamination in natural springs through traditional ecological knowledge on plants: Pathways toward sustainable mining practices and resource management
No full textThe local communities, particularly belonging to mineral-rich areas such as Marinduque, face challenges from heavy metal contamination. This study documents the traditional knowledge of the community in the utilization of plants for managing natural spring. Data were collected from ten key informants through interviews and guided walks. For comparative water analysis, samples were collected from the natural springs with and without the identified vegetation. The water samples were subjected to AAS analysis for Cu+2, Zn+2, and Pb+2. Eleven of the identified herbs were grown in a medium with known concentrations of Cu+2, Pb+,2 and Zn+2 in the laboratory for one week and analysed for accumulated heavy metals. The study identified 56 plant species, represented by 33 families. Species Dracontomelon, Dillenia, Nauclea and Duabanga, together with the Ficus, are most preferred by the old folks in cleaning natural springs. The water samples from vegetated springs showed permissible to negligible amounts of heavy metals as compared to those with no plants. The ferns showed high potentials in accumulating heavy metals. These findings show the value of traditional knowledge in the mitigation process and its relevance in the sustainable resource management in mining-affected landscapes
Utilization of the point load index method as an estimator of rock compressive strength in civil engineering
No full textLawa Cave is one of the geotourism sites located in Purbalingga, Central Java, specifically on the eastern slope of Mount Slamet. The large number of tourists visiting each year and the construction of several buildings inside the cave necessitate an assessment of how strong Lawa Cave is in terms of its load-bearing capacity. This study aims to analyze the compressive strength of the rock and provide recommendations on the safety level of the cave in withstanding the load from building structures and visitors. In this study, field observations and primary data collection were conducted, involving the collection of rock samples from several points within the cave. These rock samples were then analyzed at the Rock Mechanics Laboratory of the Mining Engineering Program at Institut Teknologi Nasional Yogyakarta. Rock compressive strength testing was conducted using the Point Load Index testing method. Conversion of the Point Load Index test results to rock compressive strength values was 11.21 MPa until 37.57 MPa. This value indicates that the Lawa Cave rock mass has adequate bearing capacity for structural buildings, suitable as a support layer for light to medium structures with recommended reinforcement such as rock bolts, wire mesh, and shotcrete
Petrographic characterization and classification of alteration zones using a spreadsheet-based system in the Kingking Porphyry Cu-Au Deposit, Barangay Kingking, Pantukan, Davao de Oro
No full textPorphyry copper-gold deposits (PCDs) are globally significant sources of copper, molybdenum, and gold, characterized by hydrothermal alteration zoning that constrains ore-forming processes and assists mineral exploration. Despite the well-established Lowell-Guilbert model, classification of alteration sub-facies remains subjective, reliant on qualitative petrographic observations. This study introduces a spreadsheet-based classification system that applies point-count modal data to automate subzone assignment in the Kingking Cu-Au deposit, Pantukan, Davao de Oro. Twenty rock samples were collected, with eight representative thin sections subjected to 500-point modal counts using transmitted and reflected light petrography. Classification thresholds, informed by global porphyry models (Lowell & Guilbert, 1970; Sillitoe, 2010; Seedorff et al., 2005) and site-specific petrography, were encoded into a VBA-driven spreadsheet. Results delineate potassic (biotite-rich and K-feldspar-rich), phyllic (quartz-sericite-clay and sericite-chlorite-clay), and propylitic (epidote-and chlorite-dominant) subzones. Overprinting textures and mineral assemblages demonstrate a classic porphyry architecture, concordant with independent descriptions of the Kingking deposit. The approach improves reproducibility and transparency in petrographic classification while highlighting the need for calibration across deposits
Species composition and diversity of flora in an abandoned mine in an island province in the Philippines: Implications for rehabilitation strategies
No full textUnderstanding the floristic composition of degraded lands, such as abandoned mine areas, is crucial for guiding effective rehabilitation. This study assessed an abandoned copper mine in an island province of the Philippines, which remained unrehabilitated after operations ceased, to document its floral species composition and diversity. Ten quadrats were established to identify thriving plant species and evaluate their conservation status and diversity indices. A total of 42 species from 27 families were recorded, with Fabaceae and Pteridaceae most represented. Twenty-one species were native to the Philippines. Dominant species included Oldenlandia corymbosa, Pteris sp., Fimbristylis littoralis, Acacia auriculiformis, Stachytarpheta jamaicensis, and Nephrolepis cordifolia. Based on plant categories, vegetation was mainly composed of ferns (40%) and shrubs or small trees (38%). Diversity indices showed heterogeneous patterns among quadrats, with some exhibiting ecological balance, while others were dominated by only a few species—typical of metal-contaminated environments. Quadrat 4 (Q4) was the most balanced and diverse, suggesting that despite harsh site conditions, patches of vegetation continue to thrive. Future studies should investigate soil properties of Q4 to guide site-specific rehabilitation strategies
Fault control on distribution of sag-ponds in Imogiri, Bantul, Yogyakarta, and Its implications for the existence of the Opak active fault
No full textSag-ponds, a prominent geological feature, may be found near the summit of Gagak Hill in Bantul Regency, Yogyakarta. These depressions, which form within volcaniclastic rocks, are strongly tied to the Opak Fault's activity. The site is made up of Semilir Formation rocks from the Western Southern Mountains Zone, which were exposed along the Mengger Hills escarpment. The purpose of this study is to determine the location and orientation of sag-ponds governed by the Opak Fault. The method is based on structural geology analysis, which is backed by field observations such as lithological descriptions, sag pond dimensions, and documenting of structural elements such fracture planes, lineaments, shear and gash fractures. The sag-ponds range in shape from round to rectangular and elongated, with lengths of 1 to 15 meters and widths of 1 to 9.2 meters. Their depths, which are often filled by rainfall, range between 0.8 and 3 meters. The development of these sag-ponds corresponds to the Opak River's east-west diversion north of Watu Gagak Hill, which caused isolated depressions along the fault zone. Overall, the presence and position of these sag ponds indicate that the examined area is being impacted by the active Opak Fault
#DEBITAAPPS: A Machine learning – based web system for diabetes mellitus detection using k-nearest neighbor algorithm to support sustainable health development
No full textThis study implemented the K-Nearest Neighbor (KNN) algorithm to build a predictive model for early detection of diabetes. Various distance metrics, namely cityblock, cosine, euclidean, and minkowski, as well as n_neighbor values from 1 to 6, were tested to determine the best combination to improve model accuracy. The dataset was divided into three parts : 80% for training, 10% for validation, and 10% for testing. The best results were obtained from the combination of the cityblock metric with n_neighbors = 3, which resulted in a training accuracy of 97.55%, validation accuracy of 94.0%, and testing accuracy of 100%. The F1 score on the test data also showed a perfect result, namely 1.00, indicating that the model can provide accurate and consistent predictions. As a real application of this research, a web application was developed designed to detect diabetes early, which is expected to be used by the community as a preventive health tool. This application allows users to easily and quickly conduct early screening for potential diabetes, thereby increasing health awareness and helping in making earlier and more appropriate preventive decisions and supporting sustainable health development in accordance with SDG 3 namely good health and well-being
Enhanced microparticle manipulation and acoustic levitation using dual-array phased ultrasonic tweezers with advanced field control
No full textPhased-array acoustic tweezers serve as powerful tools for non-contact microparticle manipulation; however, achieving stable and repeatable three-dimensional control remains a significant challenge in physical acoustics. Here, we introduce an open-source, modular Bilateral Array ultrasonic platform designed to generate both twin and vortex acoustic fields for precise particle actuation. By integrating Arduino-based logic with a custom 16-channel MOSFET driver board, the system enables real-time phase management of 128 transducers at 40 kHz. We demonstrate that this bilateral array configuration significantly enhances acoustic focusing, manipulation accuracy, and field stability compared to traditional unilateral setups. Through rigorous experimentation, we quantify the distinct stability profiles of different field topologies generated by this system. Results indicate that while vortex fields effectively induce rotation (σθ = 2.5°), they suffer from inherent vertical instability (σz ≈ 0.10 cm), resulting in particle ejection at higher elevations. Conversely, the twin configuration demonstrates superior confinement, achieving sub-millimeter precision in both horizontal (σx ≤ 0.03 cm) and vertical (σz ≤ 0.04 cm) planes. This stability facilitates complex multi-particle operations, including the synchronized rotation of four particles and controlled merging. These findings establish quantitative design guidelines for acoustic field selection, delineating the operational trade-offs between rotational torque and axial confinement for microfluidic and biomedical applications
Integrating community preferences and adaptive capacity for resilient disaster management: A choice experiment-based GIS approach
No full textThis study applies the Choice Experiment (CE) methodology to explore community preferences in enhancing community-based disaster management (CBDM) and strengthening adaptive capacity. The frequency and impact of disasters are increasing, making it crucial to understand public preferences to design effective and inclusive resilience strategies that address these challenges.Additionally, the research integrates GIS-based multi hazard and preference mapping to provide spatial insights into risk distribution and adaptive capacity across different regions of the district. This spatial analysis, combined with preference data, creates a multidimensional framework for understanding and planning community focused disaster resilience. The results show that most people prefer improving early warning systems and managing water resources wisely rather than focusing on land restoration or new farming methods. Additionally, they value giving important roles equally to make sure e1 veryone is involved in disaster planning. They also prefer using online groups to connect with others and want disaster lessons included in schools. These preferences help evaluate and make decisions-supporting more effective and equitable disaster risk management
Addressing transportation challenges in Purwokerto: A graph theory approach to accessibility and sustainability
No full textRapid urbanization and growing private vehicle ownership have led to increasing congestion and declining transport efficiency in Indonesia's secondary cities. Purwokerto, as a medium-sized urban area, faces the challenge of balancing mobility needs with sustainability goals. This study aims to identify priority areas for integrated and sustainable transportation development using a spatial-network approach. Road network and land use data from OpenStreetMap (OSM) and Rupa Bumi Indonesia (RBI) were analyzed using Kernel Density Estimation (KDE) and Graph Theory to assess road density and accessibility. It shows a 37.8% increase in road network concentration between 2015 and 2025, extending from the urban core toward Kembaran, Sokaraja, and Patikraja. Graph analysis revealed that Sokaraja 1 and Patikraja have the highest accessibility indices (1.630–1.800). Urban center areas such as Purwokerto Timur, Purwokerto Utara, and Purwokerto Selatan show lower accessibility levels. The low ones also exist in peripheral areas such as Kembaran, Baturaden, reflecting opportunities for gradual, sustainable connectivity improvement. The research identifies a hierarchy of priority zones for transport development to promote equitable, sustainable mobility. The findings align with Sustainable Development Goal 11 (Sustainable Cities and Communities) and demonstrate how medium-sized cities can plan proactively toward integrated and low-carbon transportation systems