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2007 research outputs found
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Integrated FEM, CFD, and BIM Approaches for Optimizing Pre-Stressed Concrete Wind Turbine Tower Design
No full textToday, all over the world, people are looking for sustainable energy with modern systems for the coming generations. Wind energy plays a crucial role in supplying electricity to modern systems worldwide. Onshore turbines are necessary to ensure efficient and economical operation of taller wind towers, which can reach up to 100 m. However, building taller turbine towers faces many challenges, such as complex cross-sectional design, multiple stresses, and high construction costs due to different variables. To combat these challenges, this article proposes an optimization design aimed at enhancing the cost-effectiveness of the pre-stressed concrete wind turbine industry, making it accessible to the wind turbine market and design engineers. The main idea of the research is an integration of design criteria and cost conditions by creating a C# plugin to determine the optimal design with minimum cost as an add-in to a 3D software simulating program. This integration helps to calculate computational fluid dynamics (CFD) using the finite element method (FEM) and minimizes costs in building information modeling (BIM), which covers some gaps from the previous works. The study presents a methodology for designing concrete wind towers and facilitating data exchange between finite element software (Ansys) and BIM software by IFC files. The optimization problem in this article is a multi-objective problem, with an optimal design that minimizes costs by reducing the vibrational wear satisfied by suitable structural stiffness. Results showed an optimal design for the concrete wind tower, resulting in a 24% reduction in material costs for the same height compared to conventional alternatives. Doi: 10.28991/CEJ-2025-011-02-08 Full Text: PD
Performance Evaluation of Alkaline Activated Geopolymer Binders Using RCA and Industrial By-Products as Cement Alternatives
No full textThis study explores the performance of alkaline-activated geopolymer binders using industrial by-products and recycled concrete fine aggregate (RCFA) as sustainable alternatives to traditional cement. Materials such as granulated blast furnace slag (GBFS), silica fume (SF), red brick powder (RBP), quick lime (QL), and RCA were utilized to develop eco-friendly binders with enhanced mechanical and durability properties. Experimental tests evaluated physical, mechanical, and microstructural characteristics, including setting times, dry density, flexural strength, and compressive strength. Advanced analysis with SEM and EDAX examined aggregate-binder bonding. Results highlighted the critical role of binder composition in determining performance. Balanced mixtures of GBFS, SF, and RBP achieved superior strength, durability, and compact microstructures, while excessive QL increased porosity, reducing effectiveness. Optimal flexural strength (4.24 MPa at 56 days) was observed for the G30/S40-L20 formulation, underscoring the importance of precise proportions. Composition influenced setting times, with SF delaying gelation and high QL content accelerating it. The findings demonstrate the viability of using RCFA and industrial by-products in sustainable construction, offering a pathway to reduce reliance on traditional cement. The study emphasizes optimizing binder formulations for strength and durability while addressing environmental impacts, encouraging further research into long-term performance under diverse conditions. This innovative approach highlights the potential for integrating recycled and industrial by-products into construction practices to achieve eco-friendly solutions and promote sustainable urban development. Doi: 10.28991/CEJ-2025-011-02-018 Full Text: PD
A Comparative Study of Terrestrial Laser Scanning and Photogrammetry: Accuracy and Applications
No full textThis study presents a comprehensive comparative analysis of Terrestrial Laser Scanning (TLS) and Digital Close-Range Photogrammetry (DCRP) against traditional Total Station (TS) methods for 3D spatial documentation across a range from 8.00 meters to 2.00 mm. The analysis was conducted through three scenarios: Ground Control Points (GCPs), the Kafrelsheikh University Mosque, and Kafr El Sheikh Tanta Road. Paired t-tests and ANOVA revealed statistically significant differences (p < 0.05) across all variables, with TLS demonstrating superior precision. TLS deviations in linear distance measurements were as low as 2 mm compared to TS, while DCRP exhibited variations ranging from 0.02 m to 0.30 m depending on surface reflectivity and distance. Pearson correlation coefficients exceeded 0.95 for TLS across all axes (X, Y, Z), highlighting its reliability. DCRP, while slightly less consistent, showed minor variability, particularly in the Z-axis. For road crack measurements, TLS captured lengths ranging from 180 mm to 750 mm (mean = 501.417 mm, SD = 207.341 mm), which aligned closely with DCRP results (mean = 504.867 mm, SD = 204.455 mm). The mosque's complex geometry showcased TLS's higher precision (ANOVA F = 15.78, p = 0.0001 for the Y-axis), while DCRP provided faster data acquisition and reduced costs. Both methods demonstrated significant statistical alignment, though TLS consistently outperformed DCRP in accuracy, especially for intricate structures requiring high precision. The findings emphasize the complementary strengths of TLS and DCRP, recommending their integration to achieve an optimal balance of accuracy, efficiency, and cost-effectiveness. Future research should focus on improving the precision of DCRP for detailed architectural and structural documentation while exploring hybrid techniques to enhance the reliability and scalability of 3D surveying methods. Doi: 10.28991/CEJ-2025-011-03-021 Full Text: PD
A Novel Process for Decolmatation of Wells During In Situ Leach Mining of Uranium
No full textThe objective of this research is to enhance the efficiency of geotechnical wells by using a low-toxicity ammonium fluoride substance in neutral, acidic, and alkaline environments to dissolve colmatants. The research methodology includes X-ray spectral analysis, semi-quantitative X-ray phase analysis of the colmatants, laboratory experiments, and pilot-scale tests. The study results indicate that the use of ammonium fluoride combined with soda increases the dissolution of colmatants, particularly quartz, thereby improving the flow rate and extending the inter-repair cycle of process wells. When ammonium fluoride is used with sulfuric acid, it leads to a decrease in the oxidation-reduction potential (ORP), whereas its combination with soda ash increases the ORP, both of which positively affect the efficiency of in situ leaching technology for uranium mining. The practical significance and novelty of this work lie in the development of an effective and environmentally friendly decolmatation technology using a low-toxicity reagent”ammonium fluoride in combination with soda. For the first time, this research established the dependence of the degree of quartz colmatant dissolution on the concentration of ammonium fluoride in both acidic and alkaline environments, along with observed changes in ORP and pH values over time during treatment with alkaline and acidic solutions of ammonium fluoride. Doi: 10.28991/CEJ-2025-011-04-011 Full Text: PD
Microstructural Attributes for Soft Soils Affected by Salts During Soaking and Seepage
No full textThis study investigates the impact of salts on the microstructure of natural soft soil under water soaking and seepage conditions over specific periods, comparing results to the natural soil in dry state. The soil sample was taken from a study area in central Iraq, south of Babylon Governorate. The research utilizes scanning electron microscopy (SEM) to analyze soil structure changes. The findings reveal that soaking has a slow effect on salt dissolution, gradually altering the soil's chemical composition and reducing its cohesion. In contrast, seepage accelerates salt removal, with dissolution beginning around 7 days and nearing completion by 30 days. Seepage also has a more evident effect on soil cohesion and bearing capacity compared to soaking, suggesting that improved drainage systems are crucial to prevent rapid soil degradation. SEM results further show that soaking weakens soil structure, increases porosity, and causes general degradation. Seepage causes an irregular cohesion and gradual deformation, which significantly affects soil stability under varying loads. This study provides novel insights into the effects of salt dissolution on soil behavior under different conditions, pointing out the need for better soil management in areas with saline soils. Doi: 10.28991/CEJ-2025-011-05-04 Full Text: PD
Performance Optimization of Masonry Mortar with Marble Dust, Spent Coffee Grounds, and Peanut Shell Ash
No full textThis research focused on the inclusion of spent coffee grounds (SCGs) and peanut shell ash (PSH) as variable additives and marble dust as a constant additive to cement materials to substitute aggregates and determine the effect of each variable on the properties of cement materials. To determine the influence of PSH and SCGs, these were added to mortar in 0.1, 0.2, and 0.3% proportions and were combined with microsilica and superplasticizer. To analyze the results, the compressive and flexural strengths during three-point bending were investigated. The chemical composition and microstructure of the mortar mix were investigated using Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray (EDX) spectroscopy. The results showed that incorporating microsilica into the mortar mix increased the compressive strength to over 35.42 MPa compared to the control sample's 33.4 MPa. Adding 0.1% and 0.3% of SCGs and PSH improved the compressive strength of the mortar mix to over 39.48 and 38.09 MPa, respectively. Including 0.2% SCGs and 0.1% PSH increased the flexural strength to over 4.52 and 6.0 MPa, respectively. The SEM and EDX results showed that adding 0.3% SCGs slowed down the formation of calcium silicate hydrates (C-S-H), consequently slowing down the hydration processes, and the strength gain was slower compared to microsilica. The addition of 0.3 PSH stimulated the formation of C-S-H, additionally supplying the cement matrix with such elements as Si and Al. Overall, adding SCGs and PSH has a positive effect on the mechanical and chemical properties of the mortar mix, although adding PSH is more beneficial than adding SCGs. Doi: 10.28991/CEJ-2025-011-03-09 Full Text: PD
Statistical Estimation of Reliability Values for Large-Panel Buildings Based on Passportization Results
No full textIn 2017-2018 and 2023-2024, a full passportization of the housing stock of apartment buildings in the city of Almaty (Republic of Kazakhstan) was carried out for the first time. The database includes 2666 multi-story large-panel buildings of different numbers of stories, from 2 to 9 floors. The aim of this study is to assess the reliability of standard-series large-panel buildings based on previous experimental research and passportization results, as well as to evaluate their seismic resistance and reliability using passportization data. The latest earthquakes in Almaty have allowed for refinements in seismic impact models. Therefore, the reliability assessment has been conducted considering this information using the Monte Carlo method. The technical condition of large-panel buildings has been assessed. The earthquake recurrence is taken into account according to the current "Map of seismic zoning of the Republic of Kazakhstan". Reliability value for the whole group of large-panel buildings has been obtained. It is revealed that large-panel buildings with the first flexible or brick floor are not earthquake-resistant. For the first time, the theoretical analysis of reliability and failure values for 2 types of large-panel buildings with the use of experimental data is performed. Regional peculiarities of seismic impact for Almaty City are taken into account. The results of reliability and failure values estimations are used for practical recommendations on risk reduction and expected losses in case of possible earthquakes. The novelty lies in the reliability and failure assessment based on the large-scale passportization of the housing stock in Almaty. It is established that the main types of large-panel buildings are earthquake-resistant. Estimates of earthquake resistance according to the results of passportization and the results of reliability calculations coincided. It is proposed to reinforce large-panel buildings with the first flexible or brick floor (33 buildings). The method of reinforcement should be determined by special studies. Doi: 10.28991/CEJ-2025-011-05-019 Full Text: PD
Mechanical Behavior of Concrete Beams with HDPE Plastic Waste as Partial Fine Aggregates Replacement
No full textThis study is related to using HDPE plastic bag waste applied to building structural components, specifically concrete beams. An innovation utilizes HDPE plastic waste not in shredded form but by taking advantage of the rigid physical properties of HDPE plastic waste after it is burned, crushed, and sieved to the size of sand to be used as a partial replacement (substitution) for fine aggregate (sand). The type of research conducted is experimental quantitative research to determine the flexural capacity of concrete beams made from HDPE plastic bag waste as a partial replacement for fine aggregates using the normal flexural strength testing method with two-point loading. The test specimens prepared were concrete beams with dimensions of 15 × 15 cm cross-section and 65 cm in length, with varying amounts of HDPE plastic bag waste replacement: 0.00% (normal concrete), 0.50%, 0.70%, and 0.90% of the weight of the sand. The concrete beam specimens were cured using a wet curing method and tested at 14 and 28 days of age. The results showed that at 14 days, the concrete beam specimens with variations of 0.00%, 0.50%, 0.70%, and 0.90% achieved flexural strengths of 3.16, 3.35, 2.91, and 2.97 MPa, respectively. Meanwhile, at 28 days, the specimens with variations of 0.00%, 0.50%, 0.70%, and 0.90% reached flexural strengths of 3.39, 3.95, 3.06, and 3.07 MPa, respectively. The highest flexural strength was achieved by the concrete beam specimen with a 0.50% substitution variation, both at 14 and 28 days, with values of 3.35 and 3.95 MPa, respectively, exceeding the flexural strength of the beam without HDPE plastic waste substitution (0.00%)
WatAI: AI-Based System for Real-Time Flow Monitoring and Demand Prediction in Water Networks
No full textEfficient monitoring and control of water demand are crucial for sustainable water resource management. Bogotá, Colombia, currently faces supply rationing due to climate change and ineffective public policies. This study presents WatAI (Water + AI), an AI-powered system designed for real-time flow monitoring and demand prediction in water distribution networks. The system integrates flow sensors, microcontrollers, and machine learning algorithms to capture high-resolution temporal data. A dynamic sequential artificial neural network (ANN) with ReLU activation and Adam optimization is implemented, allowing real-time adjustments (1 sec) to flow variations and anomaly detection. To enhance accuracy, the system applies real-time signal filtering and transmits early alerts via email to service providers. The ANN model achieved an MSE of 0.006510, demonstrating improved accuracy with increasing historical data. Compared to traditional forecasting models, WatAI provides higher temporal resolution and adaptability to demand fluctuations, making it a more effective tool for intelligent water management. The study contributes to the development of IoT-based smart infrastructures for sustainable urban water planning
Mechanical Characteristics of Prestressed Concrete Cylinder Pipe Strengthened by EPS and CFRP Liner
No full textPrestressed concrete cylinder pipe (PCCP) has been applied in many large-scale hydraulic engineering projects around the world. And the prestressed wire breakage is the most common form of PCCP damage. Traditional carbon fiber reinforced polymer (CFRP) liner techniques fail to fully exploit the tensile performance of CFRP. Therefore, the method of using EPS cushion and CFRP liner to strengthen the PCCP with broken wire is proposed in this study. To clarify the effect of the proposed method, a finite element three-dimensional model is established and validated using experimental data. Subsequently, the effects of EPS thickness, CFRP thickness, and wire breakage ratio on the stress-strain response of the PCCP are analyzed. Based on different failure modes of the pipe, the influence of EPS and CFRP thickness on the internal pressure bearing capacity is discussed. The study reveals that the synergistic action of the EPS cushion can effectively enhance the internal pressure bearing capacity of the PCCP. As the thickness of EPS cushion and CFRP increases, the bearing capacity almost linearly increases. Under the influence of internal pressure, visible cracks first appear in the concrete core, followed by yielding of the steel cylinder, and finally the steel wire stress reaches its ultimate strength