2031 research outputs found
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Assessing Geospatial Accuracy in Mapping Applications: A Focus on Google Earth
Get PDFGoogle Earth, among other online mapping platforms, offers an interactive mapping platform that has become indispensable for academic and research applications. It serves as a primary reference and a foundational tool for map creation, providing open-source, cost-free imagery that meets the user needs of the mapping community. As a contemporary repository of high-resolution images of Earth's landmass, Google Earth has vast potential for scientific exploration and remains an underexploited resource. Its rapid expansion and consistent reliability make it a favored source for mapping and routing tasks. However, this research underscores the crucial aspect of Google Earth's positional accuracy, which is at the heart of this study. A comparative analysis between the positional accuracy of Google Earth and traditional ground surveying maps was conducted. The Wilcoxon rank test and quantitative methods were used to evaluate coordinate discrepancies, revealing significant discrepancies between the two datasets. This study aims to provide a rigorous assessment of Google Earth's utility and accuracy in scientific and academic contexts, emphasizing its role and reliability as a critical resource for researchers and practitioners in the field of mapping. The results revealed displacement changes in both the northing and the easting coordinates. For the northing coordinates, the displacement increases when moving eastward and decreases when moving westward. For the easting coordinates, the displacement increases when moving northward and decreases when moving southward. This pattern highlights spatial discrepancies and the varying impact of location on the dataset's accuracy, emphasizing the need for targeted corrections to enhance data accuracy. These key findings provide valuable insights that could significantly contribute to optimizing mapping practices and efficiently exploiting this vast, yet underexplored, digital resource. Doi: 10.28991/CEJ-2024-010-08-012 Full Text: PD
Designing Climate-Adaptive Buildings: Impact of Courtyard Geometry on Microclimates in Hot, Dry Environments
Get PDFDesigning climate-adaptive buildings is crucial for mitigating the adverse effects of climate change by enhancing energy efficiency and reducing greenhouse gas emissions. Additionally, such designs improve thermal comfort and resilience in urban environments, particularly in regions with extreme climates, thereby promoting sustainable living conditions. This study aims to mitigate climate change through strategic urban and building design, focusing on the impact of building geometry and courtyard configurations on enhancing microclimates and thermal comfort in the UAE's hot arid climate. Utilizing ENVI-met software for qualitative analysis, the research examines design modifications in a school building's layout and courtyards. The analysis and findings reveal that strategic alterations can reduce outdoor air temperatures by up to 1.45°C and average building temperatures by approximately 1.89°C. Additionally, these modifications significantly improve thermal comfort perceptions on the PMV scale. The findings underscore the potential of architectural design to contribute to climate change mitigation efforts, highlighting the importance of thoughtful building and courtyard designs in promoting sustainable architecture and urban planning. This study offers novel insights into the role of design in enhancing thermal environments, providing a practical approach for developing climate-adaptive buildings in hot, dry environments. Doi: 10.28991/CEJ-2024-010-08-017 Full Text: PD
Comparative Study of UPV and IE Results on Concrete Cores from Existing Structures
Get PDFDynamic non-destructive methods (NDT) are particularly attractive owing to their time and cost efficiency when compared to conventional uniaxial compressive strength tests. However, the results of these methods are highly scattered; therefore, they are primarily used for qualitative material characterization. One of the most important NDT results is the calculation of the dynamic Young's modulus, which is associated to the uniaxial compressive strength (UCS) of concrete. The ultrasonic pulse velocity (UPV) is the most commonly used NDT. The limitation of this method is that it directly depends on knowledge of the Poisson's ratio, and an assumption of its value must be made. This assumption results in highly scattered results. In contrast, the impact echo method (IE) can result in a dynamic Young's modulus calculation without knowing the Poisson's ratio. The limitation of this method is that it is dependent on the specimen's slenderness, which in turn depends on the Poisson's ratio. This study investigates the IE method's applicability to short cylinders. A comparison of the UPV and IE methods is made, and the error in the dynamic Young's modulus value derived by assuming Poisson's ratio value in the UPV method is calculated. The authors conducted a numerical analysis and recently proposed the use of a shape correction factor (SCF) to apply the IE results for short cylinders, considering the influence of the slenderness (L/D) of the samples. For the first time worldwide, an extensive experimental study on 232 concrete samples with L/D ≈ 1.0 confirmed the wide spread of UPV test results and showed that it can lead to an error on Young's Modulus determination by up to 50% owing to the adoption of an arbitrary Poisson's ratio value. In contrast, using the SCF yields IE results with a ±2% error. A new methodology, ultrasonic pulse impact echo synergy (UPIES), is proposed by performing both UPV and IE tests on the specimens and using the SCF. The Poisson's ratio and, consequently, the Young's modulus can be accurately determined. Doi: 10.28991/CEJ-2024-010-09-03 Full Text: PD
Global Buckling Strength of Girts with Inner Flange in Compression
Get PDFThe objective of this paper is to provide guidance on improving the lateral-torsional buckling strength of cold-formed, channel-section wall girts subjected to leeward wind loads, which cause the inner flange to compress. Additionally, it aims to identify the cross-sectional dimensions that most affect this strength. This is necessary due to the observation that the lateral-torsional buckling strength, with the inner flange in compression, of those members is significantly lower than that of the outer flange due to the difference in lateral bracing lengths, which leads to material waste. The available methods for improving the lateral-torsional buckling of girts when the inner flange is in compression were first summarized. Then, a parametric study was performed on three typical channel cross-sections. Sixty-three cases were created by varying flange width, lip length, cross-sectional depth, and thickness within practical ranges. These cases were solved manually for lateral-torsional buckling strengths using Microsoft Excel. The results showed that increasing the flange width is the most effective way to improve the flexural strength without considering the bracing effect of sheathings, Mnl, while increasing the cross-section thickness is the best for the strength considering the sheathing effect, Mn. Therefore, a new asymmetrical section with a larger inner flange width is recommended for girts when Mnlgoverns the strength. Doi: 10.28991/CEJ-2024-010-11-05 Full Text: PD
Comparative Study of Different Classification Methods and Winner Takes All Approach
Get PDFOne of the most popular methods in remote sensing for gathering and evaluating satellite data is the classification of images. Several categories exist for image classification techniques, including supervised and unsupervised classification, pixel-based, object-based, and rule-based approaches. Each type of technique has pros and cons of its own. Choosing the method that produces the best results is one of the issues with image classification. The "best" model for classifying images relies on the particular task and the dataset used. The ideal classification technique is a crucial component in increasing classification accuracy. The strengths and drawbacks of various models vary, so selecting one that is appropriate for the job is critical. The main objective of this research is to analyze and compare the results of each classifier used, including ISODATA, K-mean, Maximum likelihood, Minimum distance, Support vector machine, and Neural network then integrate these different types of classification using the winners-takes-all classification approach in order to try to improve the results. The classified images were assessed, and both the overall accuracy and kappa coefficient were calculated and gave 79.50%, 73.89%, 77.05%, and 84.98%, 86.53%, 87.18%, and 88.69% for ISODATA, K-means, Minimum distance (MD), Maximum likelihood (MXL), Support vector machine (SVM), Neural network (NNT), and winner takes all (WTA), respectively. From the results, the Winner takes all (WTA) presented a superior in terms of the overall accuracy and kappa coefficient. Doi: 10.28991/CEJ-2024-010-10-016 Full Text: PD
Performance of Treated Date Palm Leaf Fiber as a Sustainable Reinforcement for Different Soil
Get PDFThe use of sustainable materials in geotechnical applications has increased in recent years due to their positive impacts on geo-environmental and future generations. This paper contributes to existing knowledge on geocell reinforcement of soil by proposing a new inexpensive product: cells made from natural materials, Date Palm Leaf fiber coated with Bitumen (DPLB), to improve its durability, as an alternative to commercially available high-density polyethylene (HDPE) geocells. A physical laboratory model was designed to examine the performance of the DPLB cell and HDPE cell reinforced base layer under repeated loading. The study tested different infill materials gravel, sand, and recycled asphalt pavement (RAP) in DPLB cells and HDPLE geocell-reinforced granular layers and compared them to unreinforced layers. The reinforcement's performance was assessed using elastic deformation, permanent deformation, traffic benefit ratio, and rut depth reduction. Results showed that both DPLB cell and geocell reinforced sand decreased the cumulative permanent deformations compared to the unreinforced layer. DPLB reinforcement cells improved the permanent deformation behavior by 30% due to the lateral restriction provided by the DPLB pockets on the infill materials, while the geocell improved it by 7%. The traffic benefit ratio (TBR) of geocell-reinforced RAP is 26% greater than that of the DPLB cell-reinforced RAP section, although both geocell and DPLB cell exhibited similar TBR values in the case of gravel infill materials. The experimental results showed that DPLB cells are a cost-effective and environmentally friendly substitute for commercially available HDPE geocells in soil reinforcement applications. Doi: 10.28991/CEJ-2024-010-10-018 Full Text: PD
Assessment of Fly Ash-Rice Straw Ash-Laterite Soil Based Geopolymer Mortar Durability
Get PDFGeopolymer is an inorganic form of alumina-silica that is synthesized through materials containing lots of silica (Si) and alumina (Al) originating from nature or from industrial by-products. The geopolymer binder is a two-component inorganic system consisting of solid components that have sufficient amounts of SiO2 and Al2O3 to form compounds such as fly ash, rice straw ash, pozzolan, laterite soil, slag, etc. This study aims to analyze the compressive strength, chemical compositions, and geopolymerization process of geopolymers produced from fly ash, rice straw ash, and lateritic soil bound with an alkaline activator, sodium hydroxide (NaOH), with a concentration of 12 M. The durability of the geopolymer mortar was determined by soaking for 3, 7, and 28 days using water curing and sulphate curing (Sodium Sulphate, Na2SO4, and Sulfuric Acid, H2SO4). The results showed that sodium hydroxide (NaOH) can release silica and alumina in the amorphous phase and can be used as a binder for geopolymer mortar made from straw ash, fly ash, and laterite soil without using oven heat, according to compressive strength, chemical compositions, and the geopolymerization process. The results of this study can be used to support the use of waste materials (fly ash and laterite soil) and local materials (straw ash) as geopolymer mortar-forming materials. Furthermore, it can aid in the development of eco-friendly (environmentally friendly) national infrastructure by eliminating the need for oven heat to initiate the polymerization reaction. However, this research can also be developed to increase the compressive strength of geopolymer mortar, which resembles that of conventional concrete in general. Doi: 10.28991/CEJ-2023-09-06-012 Full Text: PD
Analysis of Perceptions of Cycling Safety on Roads with Mixed Traffic Depending on Age, Gender, and Riding Experience
Get PDFPromoting cycling as a sustainable mode of transport necessitates understanding how individuals perceive the risks associated with bicycling based on age, gender, and riding experience. This study addresses a critical gap in the field of traffic by examining cyclists' perceptions of risk and safety on mixed-traffic roads. Despite increased interest in promoting cycling as a sustainable means of transportation, research on this topic is rare. Therefore, this study aims to contribute to existing literature on cyclist perceptions and cycling safety on roads with mixed traffic by examining the significant differences that may exist among age groups, genders, and individuals with varying riding experiences. The research focuses on roads lacking distinct bicycle paths and characterized by heterogeneous traffic streams. The study surveyed 120 cyclists on 13 roads in Pristina, the capital of Kosovo. Safety perception, measured using a Likert scale (1–5), was the dependent variable. Non-parametric methods, specifically the Mann-Whitney and Kruskal-Wallis tests, were employed to analyze the data and test the hypotheses. The results revealed statistically significant differences between genders (Mann-Whitney test: U = 720; Z = -5.887, p = 0.000 < 0.05; r = -0.537), between groups with and without riding experience (Mann-Whitney test: U = 1240.5; Z = -2.59; p = 0.01; r = -0.236), and among age groups (Kruskal Wallis test: df = 4; p = 0.022 < 0.05). With Bonferroni correction, post hoc analysis using the Mann-Whitney test demonstrated significant differences (adjusted p < 0.0125) between at least two age groups. The median perception of general safety was at Likert scale 3 (average safety), while the perception of comfort was at level 2 (uncomfortable). These findings provide valuable insights for policymakers involved in urban planning, offering targeted strategies to enhance cycling safety based on age, gender, and riding experience. The findings highlight the complicated interaction of these elements and their impact on riders' safety perceptions. By understanding these dynamics, policymakers and urban planners may build targeted interventions and infrastructure upgrades to promote safer and more inclusive riding environments. This work adds to the field by shining light on the elements that influence cyclists' risk perception, eventually guiding methods for improving cycling safety and boosting the use of bicycles as a sustainable transportation choice. Doi: 10.28991/CEJ-SP2023-09-011 Full Text: PD
Shear Behavior of Reinforced Concrete Inverted-T Deep Beam
Get PDFContrary to top-loaded deep beams, Inverted-T (IT) deep beams are loaded on ledges at the beam's bottom chord. The presence of the load near the bottom of the beams creates a tension field in the web at the loading points. An experimental investigation was carried out in which 8 specimens of reinforced concrete IT deep beams were tested and the effect of the following variables was studied: changing the hanger diameter, hanger arrangement in terms of spacing and distribution distance, hanger reinforcement ratio, vertical and horizontal web shear reinforcement diameter, and spacing. In addition, all the tested beams had long ledges extending to the end of the beam. It was concluded that hanger reinforcement diameter and horizontal web shear reinforcement have an insignificant effect on the IT deep beam capacity. While the change in hanger arrangement, vertical web reinforcement, and ledge length has a significant effect on IT deep beam capacity. The maximum spacing of the hanger reinforcement and the minimum hanger reinforcement ratio passing through the load plate length will be studied in the following publication. A finite element model (FEM) was presented to predict the behavior of IT deep beams. The simulation was carried out using the ABAQUS 2017 software program. The results of the numerical model showed good agreement with the experimental program. Analysis using design codes was checked against the experimental data, where the computed beam capacities were compared to those obtained from the test results. The comparison showed a remarkable difference between the predictions using the design codes and the test results. Computation using design codes significantly underestimated the capacities of the beams. Doi: 10.28991/CEJ-2023-09-05-04 Full Text: PD
The Reliability of W-flow Run-off-Rainfall Model in Predicting Rainfall to the Discharge
Get PDFThis research intends to predict the discharge (run-off) from rainfall for which the model is built using W-flow. The research location is in the Gajah Mungkur reservoir (Wonogiri) in Indonesia. The estimation of reservoir inflow has an important role, mainly in the scheme of reservoir operation and management. However, the heterogeneity of complex spatial and temporal patterns of rainfall and also the physiographic context of a watershed cause the development of a model of real-time run-off and rainfall that can accurately predict the reservoir inflow to become a challenge in the development of water resources. In relation to the analysis and prediction of rainfall, the constraint and problem that is still often faced is the minimal availability of observed rainfall data spatially as well as temporally; the time series of rainfall data is not long and complete enough; and the number of rainfall stations is less evenly distributed. The methodology consists of carrying out the literature study, collecting as much rainfall data as possible to build a W flow model, then carrying out the model calibration and analyzing the prediction of real-time reservoir inflow for operation. The result shows that the dependable discharge of the Wonogiri watershed shows that there are two peak discharges, which happened on February II (the second half of February) and December II (the second half of December). However, the discharge is decreasing in July and reaching its lowest level in October II (the second half of October). Doi: 10.28991/CEJ-2023-09-07-015 Full Text: PD