Published: 2024-10-29
Rework in civil construction projects at design phase: Influencing factors and suggested solutions
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Among the various project phases, the design phase often contains errors that result in rework in civil construction projects. This rework can lead to budget overruns, schedule delays, and a decline in construction quality. There is rare knowledge of reworks in civil construction projects, especially in the design phase. This paper presents an overview of the influencing factors and solutions for reworks in civil construction projects at the design phase. To achieve this objective, a survey on the causes of rework was conducted with experts experienced in designing and constructing civil projects in southern Vietnam. Civil engineers and investors involved in the project at the design phases were targets of the survey. Five groups, including designers, design managers, investors, subcontractors, and objective conditions, were selected for designing survey questionnaires. Then, the PCA (principal component analysis) was applied to the collected data to reveal the most influencing factors on rework causes. Based on the results obtained, several suggestions are proposed to minimize rework in civil construction projects. These findings can serve as valuable insights for investors and design consultants, fostering learning and process improvements to reduce rework in future projects.
Development of the intelligent traffic light system based on image processing and fuzzy control techniques
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In Viet Nam's current traffic conditions, congestion and jams—especially at intersections during peak hours—present major challenges. Traditional traffic light systems, which rely on fixed timing principles, often fail to manage traffic flow efficiently, particularly when vehicle density varies significantly across different directions. This research aims to develop an intelligent traffic light system where the signal timings automatically adjust based on the vehicle density at intersections. The study uses an object recognition algorithm to identify, classify, and count vehicles. The data was then fed into a fuzzy logic model to calculate the optimal signal timings. Experimental results demonstrate an accuracy of approximately 88% in vehicle detection. The fuzzy logic model and the programmable logic controller were able to effectively compute reasonable signal timings based on real-time vehicle density. Future developments include expanding the system's functionalities, creating a user-friendly interface, and developing a management application for mobile devices.
Removal of Dibenzofuran from aqueous solution by sugarcane bagasse-based biochar
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Dibenzofuran (DBF) has been considered an environmental risk due to its high toxicity and risks to human health and ecosystems. Among wastewater treatment technologies, the adsorption process has emerged as a potential solution to remove organic pollutants efficiently, including dibenzofuran, in wastewater. The study aims to investigate the feasibility of sugarcane bagasse-based biochar for DBF removal through adsorption. Biochar characteristics showed a high specific surface area of up to 498.97 m2/g and abundant functional groups on the material surface, resulting in high removal performance of DBF with average adsorption efficiency and adsorption capacity reaching maximum values of 98.43% and 96.77 mg/g, respectively. The optimum parameters were suggested for DBF removal: pyrolysis temperature of 700oC, contact time of 50 min, biochar dosage of 0.5 g/L, and DBF concentration of 40 mg/L. Furthermore, the results of adsorption kinetics and adsorption isotherms indicated that the adsorption process benefits DBF removal. Pseudo-second-order model and Langmuir model can describe the DBF removal process due to the best fit to experimental data (R2 > 0.98). Based on these findings, sugarcane bagasse-based biochar could be utilized efficiently to remove DBF from wastewater.
Removal of tetracycline antibiotic from aqueous solution using bimetallic CuCo-ZIFs as an efficient catalyst in the presence of hydrogen peroxide
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Antibiotics play an important role in disease treatment; however, they are also a threat to public health and the ecosystem. Therefore, a bimetallic CuCo-ZIFs catalyst was manufactured through the ultrasonic-assisted solvothermal method to activate H2O2 towards the removal of tetracycline (TC) in an aqueous environment, a polluting broad-spectrum antibiotic model. PXRD, SEM, TEM, EDX, TGA, FT-IR, and BET analyses indicated that CuCo-ZIFs cubic crystals were successfully synthesized with high crystallinity, large specific surface area, and ideal thermal stability. Factors affecting the TC removal were investigated, including CuCo-ZIFs dosage, H2O2 concentration, treatment time, initial TC concentration, and reaction temperature. The results showed that the CuCo-ZIFs/H2O2 catalytic system was capable of effectively handling TC, with about 93.9% of TC removed in the presence of 0.3 g.L-1 CuCo-ZIFs, 0.01 mol.L-1 H2O2 at room temperature within 30 min. Conclusively, this study contributes to expanding the application potential of bimetallic CuCo-ZIFs materials to eliminate antibiotic residues in an aqueous environment and inspire research on environmental improvement.
Static and dynamic power splitting protocol enabled in DF energy harvesting Half-Duplex relaying network: Ergodic capacity analysis
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In this research, we propose and examine the DF Energy Harvesting Half-Duplex Relaying Network. For this system model, the DF Energy Harvesting Half-Duplex Relaying Network is analyzed in two cases: Static and Dynamic Power Splitting Protocol. The Ergodic Capacity (EC) is introduced and derived in relation to all the primary system parameters in order to evaluate system performance. The Monte Carlo simulation results demonstrate that the mathematical and simulation are in agreement, thereby confirming the accuracy of the analytical description.
Exploring the effects of waste plastic aggregate on styrene-butadiene-styrene-modified asphalt binders for sustainable rural pavements
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In addressing the imperative need for sustainable and cost-effective solutions in rural pavement development, this study navigates the intricate balance of environmental and financial constraints to ensure the resilience of infrastructure in communities with limited resources. The focal point is the integration of waste plastic aggregate (WPA) into hot mix asphalt, augmented by the inclusion of styrene-butadiene-styrene (SBS) for an elevated level of performance. The findings underscore a gradual decrease in the tensile strength ratio, emphasizing a manageable impact, transitioning from 82.4% in the control to 73.7% at 6% WPA. Noteworthy is the observation of marginal reductions in indirect tensile strength and stiffness, particularly notable at higher WPA levels. Dynamic modulus testing highlights susceptibility to rutting at lower frequencies, while high-frequency results demonstrate stability up to 6% WPA. The Hamburg wheel tracking test signals heightened rutting at 3% and 6% WPA, indicating potential challenges in deformation resistance. Despite a slight dip in strength, the discernible magnitude of this reduction is not substantial. This affirms that the incorporation of WPA achieves a harmonious enhancement of sustainability without compromising critical mechanical properties.
Evaluating pile foundation design due to groundwater level lowering
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In Viet Nam, ground subsidence has been occurring at an alarming rate, raising concerns for pile foundation design. This issue is primarily caused by excessive groundwater extraction for water supply, irrigation, aquaculture, and other uses. Thus, in this study, the evaluation of pile capacity due to groundwater level (GWL) lowering as a preliminary guideline for structures is proposed. This study analyzed different cases of GWL lowering from 0 m to 2 m, and pile size varied from 18 x 18 cm to 45 x 45 cm, to evaluate the allowable bearing capacities for single piles and pile groups. The results indicated that when lowering the GWL from 0 to 2 m, the allowed bearing capacity varied by 5.75–174.70 tons for single piles and 11.95–808.18 tons for pile groups. Besides, when the pile size increased, the bearing capacity increased in the range of 6.38–41.46 tons (size 18 x 18 cm) to 16.30–174.70 tons (size 45 x 45 cm) for a single pile and 11.95–191.81 tons (size 18 x 18 cm) to 33.49–808.18 tons (size 45 x 45 cm). The result of this study underscores the significance of predicting the bearing capacity of pile foundations due to the variation in groundwater level.
Integrating the cellular vortex method with remote sensing and geographical information systems in the modelling of coastal flooding around Niger Delta
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Coastal areas are increasingly vulnerable to flooding, necessitating accurate simulation methods to understand flood dynamics and their potential impacts. This study employed a Lagrangian framework integrating the cellular vortex method with remote sensing and GIS to simulate flood height distribution in a coastal region. Leveraging climatic and remotely sensed data, alongside ArcMap 10.6.1 for map processing, the research estimated flood magnitude and frequency using the L-moment approach, applied to a forty-year tidal record dataset. Essential input parameters, such as the roughness coefficient and curve number, were derived from land use and land cover characteristics. Additionally, river flow velocity was observed at 0.12m/s, with measured wind speed and direction recorded at 4m/s in the northwest direction. Notably, analysis of the initial flood height distribution map revealed a significant expansion of wetland areas, attributed to observed land use changes between May 2002 and July 2005. Projections for flood height distribution in 2025 and 2050 highlighted the emergence of tidal floods, emphasizing the critical role of considering future climate and land use scenarios in flood dynamics assessment. This research contributes to advancing understanding of flood modeling techniques and underscores the urgency of adaptive measures to mitigate the potential impacts of coastal flooding.
Assessing aquifer vulnerability near cemeteries using dipole-dipole and vertical electrical sounding methods
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An integrated geophysical investigation of the second cemetery in Benin City was conducted with the view to determine the leachate flow direction and the geoelectrical layers that characterized the underlying aquifer. Eight vertical electrical soundings (VES) and two dipole-dipole profiling lines along two transverse sections were carried out. For the dipole-dipole profiling, ABEM Terrameter SAS 300C was employed, while the VES investigation utilized the Schlumberger array. The resistivity data collected during the field investigation were interpreted using DIPROWIN software version 4.01. Leachate plume was identified in the subsurface soil at a depth range of 5 to 20 meters. This was attributed to the soil porosity, aiding the infiltration of necroleachate. The VES results revealed four geoelectric layers: topsoil, lateritic soil, a weathered layer (composed of clay), and medium to coarse sand. The overburden exhibited a thickness range of 0.7762m to 0.8074m, resistivity ranging from 57.318Ωm to 2831.4Ωm, and depths ranging from 0.7762m to 1.5836m. The third geoelectric layer, identified as clay, had an average thickness of 11.48 meters at a depth of 13.06 meters, with a resistivity of 203.52Ωm. Apart from acting as a seal against the downward penetration of leachate, the clay also serves as a filter.
Greenhouse gases emission trade-offs for benefits gain - An analysis from paddy rice and upland crops cultivation in Hau Giang province, Viet Nam
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Agriculture activities require energy for operation and emit greenhouse gases (GHGs) into the atmosphere. However, agriculture provides essential nutrients with carbon sources through its main and by-products. This study used the life cycle assessment methodology to evaluate the carbon balance in agricultural systems of paddy rice (PR), corn, mung bean (MB), and black sesame (BS) in the summer-autumn growing season in the Vietnamese Mekong Delta. The results showed that PR and upland crops produced a net carbon source of 1,280.9–18,915 kg-C ha–1. Corn cultivation achieved the best value in carbon index analyses. To have one calorie from grain, selected crops must trade off 115.19–501.81 mg-CO2e. This study concluded that four selected crop cultivations achieved carbon analysis benefits. However, corn is a suitable recommendation for adapting to the agricultural conversion from PR farming to better upland crop cultivation.
Physicochemical and toxicological characteristics of leachates and water quality around dumpsites in Lagos Nigeria
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Improper waste management leading to contamination of groundwater resources is a global environmental issue. This study examined the physicochemical and toxicological characteristics of leachates and their effect on water quality around the dumpsite in Alimosho Lagos, Nigeria. Samples of water and leachates were collected from boreholes around the dumpsite. Physiochemical and toxicological characterization of water around the dumpsite was based on American Public Health Association standards. Seventeen physiochemical and heavy metals of leachate and borehole water samples were analysed. The result of the study shows that the temperature, odour, appearance and turbidity of the water in the study area were within the limits set by WHO. However, the pH was below the WHO limits indicative of the acidity of the groundwater. The presence of Pb, Cr, and Cd confirmed leachate pollution. The contemporary effects confirmed the insignificant effect of the dumpsite operations at the groundwater source. Without a properly designed leachate series system, uncontrolled accumulation of leachates at the bottom of the dumpsite poses capacity infection dangers to groundwater resources. It is recommended that proper disposal of waste, in addition to implementing a higher sustainable environmental sanitation practice, is needed to ensure the safety of groundwater within the locality.
A comparative study of teaching internship practices: Insights from Can Tho University and Quirino State University
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This study compares the implementation of teaching internship (TI) guidelines and practices at the School of Education, Can Tho University (CTU), Viet Nam, and the College of Teacher Education, Quirino State University (QSU), the Philippines. Using a qualitative research approach, the study applied Braun and Clarke’s (2006) thematic analysis with Delve Software for coding. Data was collected through document analysis. Findings reveal that while both universities share certain aspects in the implementation of guidelines and practices, notable differences were also observed. These distinctions present valuable opportunities for both institutions to improve and enhance their teaching internship programs.
Efficacy of Jigsaw learning in teaching volleyball skills to grade 12 students
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Playing volleyball is one of the Physical Education courses in the Philippines. However, playing it is not mastered due to a lack of research-based strategies. This study determined the efficacy of Jigsaw learning in teaching Volleyball in Grade 12 at Biliran Province State University-Main Campus, Naval, Biliran during the academic year 2022–2023 as a basis for a proposed skills enhancement activity. The study used a quantitative descriptive-correlation research design. There were one hundred (100) respondents. The skills performance of the students was good after using jigsaw learning in teaching volleyball as to, serving, passing, setting, spiking/attacking, and blocking. The students’ skills performance before and after using jigsaw learning in teaching volleyball were significantly related. Jigsaw learning was efficient in teaching volleyball. Thus, the Jigsaw model is used to make the students more skillful and competent.
K to 12 implementation in Siquijor: The senior high school students’ lived experience
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The Philippines has finally shifted to the K to 12 curriculum, with a senior high school program. This study explored the students’ lived experiences in Senior High school. A qualitative research design utilizing the 5-step Interpretative Phenomenological Analysis was used. Ten students from the 10 Senior High Schools in the Province of Siquijor, Philippines participated and were randomly selected and interviewed using a semi-structured interview guide. The following themes emerged: a) opportunities, b) challenges, and c) uncertainties. Likewise, the students had taken advantage of the opportunities to acquire future-ready skills, student-centered instruction, and adequate learning materials, and were mentored by high-performing teachers. There were challenges caused by the inadequacy of the facilities and the difficulty of the curriculum. Uncertainties about the support of the community and the tracks that the students wanted to pursue were also prevalent in their responses. Therefore, the implementation of the new curriculum has some positive developments and areas for improvement.
Factors influencing environmental and circular economy disclosure of Viet Nam listed companies
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This study examines the environmental and circular economy disclosures (ECED) level and factors influencing this level of 32 Vietnamese listed companies from 2018 to 2022. The content and frequency analyses are performed to determine the level of ECED, and regression analysis is to investigate the influencing factors. Drawing on a sample of 160 sustainable development and annual reports following the Global Reporting Initiative frameworks (GRI), the study evidenced that 32 listed companies paid great attention to the GRI 300 category (on environment topics) with the top three GRI standards 302 (energy), 307 (environmental compliance), and 303 (water and effluents), respectively. In addition, the Feasible Generalized Least Square method results showed that the companies with government ownership and Big4 audit services had a higher level of ECED. In comparison, larger companies had a lower disclosure level. Meanwhile, companies in the manufacturing sector with foreign shares and the independence of the Board of Directors did not affect the disclosure information disclosure level in the studied sample.