Indang Dewata

Padang City experiences recurrent flooding because intense rainfall, rapid runoff from eastern catchments, low-lying floodplains, and coastal–estuarine backwater effects interact across a developed watershed continuum. Existing assessments often examine rainfall, runoff response, spatial hazard, and ecological functions separately, limiting integrated flood-risk reduction and land-use planning. This study aims to 1) analyze areal rainfall frequency for 1995–2025 using the Annual Maximum Series of 24-hr Rainfall (R24/AMS), the Log-Pearson Type III (LP-III) distribution, and the Kolmogorov–Smirnov (K–S) goodness-of-fit test; 2) generate a preliminary regional-scale runoff hydrograph using the Nakayasu Synthetic Unit Hydrograph (SUH) to characterize event magnitude and response timing under design rainfall; and 3) map flood-hazard zones using GIS-based weighted overlay scoring that integrates hydrological, geomorphological, and ecological parameters. Rainfall records indicate interannual variability and repeated ≥ 150 mm/24 hr events, including 447 mm on March 7, 2024 and 261 mm on November 25, 2025. Design 24-hr rainfall increases from 160.87 to 334.14 mm across 2- to 50-year return periods, producing 4-hr intensities of 22.13–45.97 mm/hr. The preliminary Nakayasu scenario yields peak discharges of approximately 135–250 m³/s with short times to peak and should be interpreted as screening evidence rather than basin-specific engineering estimates. The flood-hazard map classifies 537.97 km² (77.41%) as Safe, 96.74 km² (13.92%) as Low, 36.76 km² (5.29%) as Moderate, and 23.49 km² (3.38%) as High. Moderate- and high-hazard areas cluster in fluvial–marine lowlands such as floodplains, backswamps, coastal alluvium, river corridors, and estuaries. These findings provide a basis for Ecosystem-based Disaster Risk Reduction (Eco-DRR) through retention-space protection, river setbacks, wetland restoration, upland recharge conservation, and erosion–sediment control.

The formation of tetracalcium aluminoferrite within the CaO-Al2O3-Fe2O3 system significantly influences clinker phase evolution and cement performance. The limited availability of high-grade Fe2O3 has encouraged the exploration of alternative iron-bearing materials, such as iron sand, for sustainable clinker production. This study investigates the effect of iron sand derived Fe2O3 on phase formation in a CaO-rich CaO-Al2O3-Fe2O3 system through a combined thermodynamic interpretation and experimental approach. Laboratory scale clinkerization was conducted at 1050–1450 °C with Fe2O3 contents of 1-5 wt%. Phase evolution and microstructural characteristics were analyzed using X-ray diffraction and scanning electron microscopy. The results indicate that Fe2O3 derived from iron sand enhances ionic diffusion and promotes early phase formation at 1050-1250 °C, leading to a reduction in free CaO. At higher temperatures, increasing Fe2O3 content facilitates liquid phase formation and stabilizes ferrite phase, while excessive Fe2O3 suppresses the formation of reactive C3S. A Fe2O3 content of approximately 3 wt% provides a balance between silicate and ferrite phases, approaching industrial clinker composition. These findings demonstrate that iron sand derived Fe2O3 not only acts as a fluxing agent but also influences phase equilibrium and clinker mineralogy. This study provides insight into the utilization of impurity bearing iron sources for improving clinker formation and supports the potential application of iron sand as an alternative raw material in cement production.

Tuberculosis (TB) remains one of the most burdensome infectious diseases in Indonesia. One contributing factor is the environment, particularly issues related to household ventilation and lighting. TB control efforts do not solely rely on medical interventions but also require a community-based approach that emphasizes active community involvement in preventing and controlling environmental risks to TB transmission. This study aims to analyze risk factors, distribution patterns, and their implications for environmentally based TB transmission risk control strategies. A mixed-methods design was conducted in two stages: first, risk factor analysis (with a case–control approach) and disease distribution pattern determination on environmental variables were performed, followed by a multidimensional scaling model (by using the Rapid Appraisal for Fisheries (RAPFISH) method) according to sustainability dimensions (ecological, economic, social, institutional, and technological) based on the resulting significant variables/indicators. This research was conducted in 2024, in four villages/nagari in West Sumatra of Indonesia. For quantitative analysis, data were collected through interviews, physical measurements of the environment, and determination of the coordinates of the residences of people with TB. Data were analyzed using bivariate and multivariate analyses. For the distribution pattern, Nearest Neighbor Analysis (NNA) in the ArcView program version 3.1 was used. Meanwhile, for qualitative data collection, focus group discussion (FGD) was performed. This study found that poor ventilation, minimal lighting, and a lack of stigma competency significantly increased the risk of TB transmission. Varied distribution patterns between regions demand adaptive and locally based strategies. The community-triggering approach is key to building community awareness and participation in creating a healthy and TB-free home environment.

While Artisanal and Small-Scale Gold Mining (ASGM) severely contaminates watersheds with mercury (Hg), existing studies primarily diagnose pollution levels without identifying the underlying transport mechanisms or actionable engineering solutions. Addressing this gap, this study analyzes Hg concentrations, identifies physical transport vectors, and proposes a data-driven mitigation framework for the Kuantan River, Indonesia. A targeted spatial sampling (n=10) was conducted during the dry season (June 2025), with water samples analyzed using Cold Vapour Atomic Absorption Spectrometry (CVAAS). Results revealed gross contamination, with 100% of samples exceeding the World Health Organization (WHO) limit of 0.001 mg/L (ranging from 0.0027 to 0.0081 mg/L). The Heavy Metal Toxicity Load (HMTL) indicated critical toxicological risks (3.94–11.81). Crucially, Principal Component Analysis (PCA) identified Total Dissolved Solids (TDS) as the dominant spatial transport vector, demonstrating that Hg is predominantly particulate-bound rather than dissolved. To mitigate this, a hierarchical engineering framework is proposed, featuring source control (mercury-capturing retorts), pathway interruption (sedimentation basins to trap TDS), and receptor protection (point-of-use filtration). Although limited by a small sample size, this study extends foundational environmental engineering knowledge by linking statistical transport diagnostics to structural interventions, offering a replicable policy and watershed management blueprint for ASGM-impacted regions globally.

Sustainability issues and environmental impacts of synthetic dyes have encouraged increased exploration of environmentally friendly natural dye sources. This study aims to identify the potential of local plants from the highlands of West Sumatra as a source of natural dyes, and to analyze the effect of mordant types on color variation and fastness in cotton fabrics. Ten local plant species were used as sources of natural pigments from leaves and bark. Three types of mordants—alum (KAl(SO4)2•12H2O), calcium carbonate (CaCO3), and tunjung (FeSO4•7H2O)—were applied to produce color variations. Fastness tests were conducted using three types of washing agents (Lerak Extract, Soklin Liquid, and Soklin Bleach) and analyzed quantitatively with a spectrophotometer at a wavelength of 625 nm. The results showed that the use of mordant significantly affected the intensity and color fastness. Tunjung tends to produce darker colors and has the best resistance for guava leaves (Psidium guajava), while alum is more effective for ambacang (Mangifera foetida) skin. Some materials such as pomegranate peel and guava peel show high resistance without the use of mordant due to their strong natural tannin content. Natural detergent Sari Lerak is proven to be the safest for maintaining color stability compared to commercial chemical detergents. These findings confirm that the highlands of West Sumatra have a potential diversity of flora as a source of sustainable natural dyes. This research provides a scientific basis for the development of environmentally friendly ecoprint technology based on local wisdom and supports the transition towards a sustainable textile industry in Indonesia.

This study is motivated by the limited research on the use of natural biocoagulants for microplastic removal, despite the significant environmental and human health impacts of this phenomenon. The aim of this research is to analyze the influence of pH variation, chitosan dosage, and settling time on the coagulation effectiveness of polystyrene (PS) microplastics, and to determine the process's optimum conditions. A quantitative method was employed, using PS microplastic solution samples (30 mg/L) treated under varying pH levels (4–10), chitosan doses (10–50 mg/L), and settling times (10–50 minutes). Data were collected through laboratory experiments and analyzed using Fourier Transform Infrared (FTIR) spectroscopy and stereo microscopy. The results indicate that optimum conditions were achieved at pH 6, with a chitosan dose of 30 mg/L and a settling time of 30 minutes, resulting in microplastic removal efficiency exceeding 90%. These findings support the theory of electrostatic interactions between the amine groups in chitosan and the negatively charged surface of microplastics. The main conclusion is that crab shell-derived chitosan is effective as an environmentally friendly biocoagulant for reducing microplastic content in wastewater. The study contributes to the growing literature on biocoagulation and offers practical recommendations for wastewater treatment managers to adopt sustainable natural coagulants. Moreover, it opens avenues for future research on chitosan-based composites for treating various types of microplastics.

This study aims to determine the optimal pH and stirring speed for the identification and removal of polyethylene terephthalate (PET) microplastics using chitosan extracted from crab shell waste (Scylla serrata) through the coagulation method. The chitosan extraction process involved demineralization, deproteinization, and deacetylation stages. Subsequently, the extracted chitosan was applied as a coagulant in a solution containing PET microplastics under various pH levels and stirring speeds. The results indicate that chitosan derived from crab shell waste is effective in reducing microplastic concentrations, achieving a removal efficiency of 97.30% under optimal conditions of pH 6 and a stirring speed of 250 rpm. These findings highlight the significant potential of utilizing marine waste as an eco-friendly natural biopolymer in microplastic wastewater treatment. This research contributes to the advancement of sustainable biopolymer-based waste treatment technologies and supports efforts to mitigate microplastic pollution in aquatic environments.

Microplastic pollution in wastewater has become an urgent environmental issue due to its resistance to degradation and its potential to contaminate the food chain. This study aims to develop a natural coagulant based on chitosan extracted from the waste shells of Scylla serrata (blue swimming crab) as an eco-friendly solution for precipitating polystyrene (PS) microplastics in wastewater. Chitosan was obtained through demineralization, deproteinization, and deacetylation processes, and its effectiveness was tested in a solution containing 50 mg of pure PS microplastics in 250 ml of wastewater. The results showed that the optimum pH for coagulation was 5, achieving a removal efficiency of 98.4%. The optimal chitosan concentration was 0.5%, resulting in a 97.6% removal rate, while the optimal stirring speed of 700 rpm yielded an efficiency of 89.2%. These findings indicate that chitosan derived from crab shell waste is an effective and sustainable coagulant for mitigating microplastic pollution and holds promising potential for application in environmentally friendly wastewater treatment.

This study analyzes trends, collaborations, and research developments on augmented reality (AR) in mathematics education using a bibliometric approach. Data were collected from the Scopus database on July 31, 2024, identifying 542 documents published between 2015 and 2024. After screening, 194 journal articles were selected for analysis. Using VOSviewer, the study produced visualizations related to document types, publication trends, journal sources, research subjects, institutions, countries, keywords, and author collaborations. The results show that 88.7% of the documents are journal articles, indicating that this topic is predominantly published in scholarly journals. Publication trends reveal significant growth since 2016, peaking in 2024, reflecting increasing global interest. Education Sciences and IEEE Access are among the top journal sources. Subject-wise, social sciences and computer science are the main disciplines exploring AR in mathematics education. Chitkara University (India) and Johannes Kepler University Linz (Austria) are leading institutions, while the United States, Malaysia, and Spain contribute the most publications. Keyword analysis shows rapid growth in research using terms such as "augmented reality" and "mathematics education," emphasizing the role of immersive technology in enhancing student engagement and conceptual understanding through visual and interactive learning. Influential authors like Lavicza, Mantri, and Haas highlight the importance of global collaboration. Based on a thematic analysis of the most-cited articles, this study proposes the AI Mathematical Education Impact and Outcome Framework. In conclusion, although research on AR in mathematics education has significantly advanced, further studies are needed to evaluate its effectiveness across varied educational contexts.

This research aims to evaluate the effect of noise on workers’ cardiac and diastolic blood pressure and explore the role of ear protection in mitigating the impact of noise in Taratak Kampung Baru, Pariaman City. The research used a cross-sectional observational design with 20 respondents from a sawmill. Data was collected through questionnaires and blood pressure measurements before and after noise exposure. In addition, this research also examined the impact of noise pollution on wildlife habitats around the sawmill location, including bird species and small mammals that are indicators of environmental quality. Bivariate analysis was conducted using the Fisher Exact Test to test the relationship between noise intensity, ear protection uses, and blood pressure. The results showed that workers who did not use ear protection experienced a significant increase in cardiac and diastolic blood pressure after exposure to noise > 85 dB. In contrast, workers who used ear protection showed lower blood pressure. These findings also indicate a correlation between high noise and a decrease in local bird populations, which is an early sign of ecosystem disturbance. This research suggests that high-intensity noise not only contributes to increased blood pressure in workers but also affects environmental quality more broadly.