2031 research outputs found
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Carbon Sequestration Dynamics in Urban-Adjacent Forests: A 50-Year Analysis
Get PDFAchieving carbon neutrality is crucial for urban ecosystems. Forests growing near cities largely determine the state of the environment in urban areas. The aim of the present research is to assess the carbon productivity dynamics in forests near Krasnoyarsk (a large industrial center) over a 50-year period in terms of carbon sequestration and conservation. The study was based on forest inventory conducted in Karaul'noe Forestry in 1972, 1982, and 2002 and forest inventory covering six forest compartments in 2022. The forest covers 3980 ha and consists of 52 forest compartments. The analysis was based on the assessment of carbon productivity dynamics and followed four levels of principles: forestry, structure, forest compartment, and forest stand. The research was based on forest fund dynamics, analyzing methods, long-term forest inventory, assessing carbon stock, and growing stock dynamics. Pine is the dominant forest-forming species that absorbs the most carbon in the study area. Pine is long-lived, covers a vast area, and has the highest carbon sequestration potential. At the forest structure level, the predominant carbon pools are mid-late successional and late successional stands dominated by pine, birch, and aspen. Forest compartment-level analysis revealed three trends in carbon sequestration: carbon balance, a decrease in carbon sequestration, and an increase in carbon sequestration. Notably, the prevailing trend is determined by changes in carbon sequestration by dominant forest-forming species (pine). Forest stand-level analysis showed that stands have become more and more uneven-aged. About 65% of total carbon stock is concentrated in mid successional, mid-late successional and late-successional stands, and 35% in young stands. The carbon sequestration rate decreases in forests with age. However, pine forests increase biological productivity and continue to successfully sequester carbon. Deciduous forests have lost their carbon sequestration potential, and the area they occupy is currently decreasing in the study area. The development of the young generation in pine stands suggests that the carbon sequestration potential in forests growing near the city will not decrease and may even increase due to climate change. Doi: 10.28991/CEJ-2023-09-09-08 Full Text: PD
The Impact of Aspect Ratio, Characteristic Strength and Compression Rebars on the Shear Capacity of Shallow RC Beams
Get PDFThis paper investigates the impact of the aspect ratio, the characteristics strength of the concrete, and the compression steel ratio on the shear capacity of wide-shallow beams. An experimental program consists of seven specimens, including a control specimen, all tested under a three-point load test. Three specimens were considered for each parameter (the control specimen was included in all three variables). The experimental results were compared to the theoretical values of six different codes of practice; they were also analyzed to determine the ductility, stiffness, and dissipated energy of each specimen. The results indicated that the shear reinforcement was fully functioning until it yielded, with a minimum contribution of 55% of the total shear capacity of the specimens. The aspect ratio and the characteristic strength had a notable impact on the shear capacity of the specimens, while the compression steel ratio had a minor effect on the shear capacity, but it improved the stiffness and the ductility of the beams. Theoretical concrete shear strengths from design codes ranged between 77 and 163% of the experimental values; EN-1992 was the closest code to the experimental results. A comparison between the experimental results and predicted values using GP and EPR methods from previous research showed accuracies of 72% and 81%, respectively. Doi: 10.28991/CEJ-2023-09-09-012 Full Text: PD
Enhancing Environmental Sustainability in a Critical Region: Climate Change Impacts on Agriculture and Tourism
Get PDFThe Ardabil Plain is pivotal in the national agricultural sector and ranks among the leading agricultural and horticultural production provinces. The primary objective of this study is to enhance environmental sustainability in this critical and vulnerable region, particularly in the face of imminent droughts and climate change. The study examines the impacts of climate change on agriculture and tourism in the area. It puts forward suggestions for implementing sustainable practices to safeguard the well-being of the local population. The results indicate a 38% reduction in precipitation, especially in the autumn season, with a possible alteration in the timing and strength of rainfall. Also, a notable decline in production volume, particularly in a specific region of the Ardabil plain, has been observed. The Ardabil Plain currently produces 284,182 tons of wheat, with 204,980 tons from irrigated crops and 79,202 tons from rain-fed crops. However, the projected future scenario indicates a decrease in total wheat production to 209,196 tons, with 160,125 tons from irrigated crops and 49,071 tons from rain-fed crops. This decline in production is expected to lead to a total net income loss of approximately -45,095,663 attributed to irrigated crops and -$30,293,396 to rain-fed crops. The study findings suggest that the availability of water sources in certain regions may prompt a shift in farming land from the north to the south of the plain to promote environmental sustainability. This demographic change could have significant financial and social implications for the region's growth and prosperity. Moreover, increasing temperatures in the western and northern regions pose flood risks and uncomfortable travel conditions, particularly concerning given the reliance on tourism and potential unemployment consequences. It becomes imperative to adopt sustainable practices and manage resources effectively to ensure the region's resilience and prosperity in the face of environmental challenges. Doi: 10.28991/CEJ-2023-09-11-01 Full Text: PD
Study on Mechanical and Durability Properties of East Borneo Double Layer Porous Concrete Paving Block
Get PDFMassive infrastructure development in East Borneo has reduced the water catchment area. One of the efforts to overcome this is by implementing porous paving with superplasticizer and local materials to improve quality, overcome material scarcity, and save costs. The purpose of this study was to determine the best layer variation of porous paving using Palu and Senoni materials with variations of 1/4, 1/2, and 3/4 of Senoni aggregate. In this study, the test object was made in the form of a beam with a quality of concrete planned at K300 MPa according to the compressive strength, flexural strength, porosity, and permeability values tested at the ages of 7, 14, 21, and 28 days. Based on the results, the variant layer of 1/4 Senoni obtained maximum compressive strength, flexural strength, porosity, and permeability of 17.306 MPa, 3.984 MPa, 18.120%, and 0.216 cm/second at the age of 28 days, respectively. Thus categorized this combination as C quality. Which was included in the C quality group with an application as a pedestrian area. According to the permeability result, double-layer porous paving can accelerate water absorption on the surface to prevent waterlogging when it rains. The increasing variation of layers in double-layer porous paving affects the compressive strength, flexural strength, porosity, and permeability. Doi: 10.28991/CEJ-SP2023-09-012 Full Text: PD
AI Mix Design of Fly Ash Admixed Concrete Based on Mechanical and Environmental Impact Considerations
Get PDFIt has become very important in the field of concrete technology to develop intelligent models to reduce overdependence on laboratory studies prior to concrete infrastructure designs. In order to achieve this, a database representing the global behavior and performance of concrete mixes is collected and prepared for use. In this research work, an extensive literature search was used to collect 112 concrete mixes corresponding to fly ash and binder ratios (FA/B), coarse aggregate and binder ratios (CAg/B), fine aggregate and binder ratios (FAg/B), 28-day concrete compressive strength (Fc28), and the environmental impact point (P) estimated as a life cycle assessment of greenhouse gas emissions from fly ash- and cement-based concrete. Statistical analysis, linear regression (LNR), and artificial intelligence (AI) studies were conducted on the collected database. The material binder ratios were deployed as input variables to predict Fc28 and P as the response variables. From the collected concrete mix data, it was observed that mixes with a higher cement content produce higher compressive strengths and a higher carbon footprint impact compared to mixes with a lower amount of FA. The results of the LNR and AI modeling showed that LNR performed lower than the AI techniques, with an R2(SSE) of 48.1% (26.5) for Fc and 91.2% (7.9) for P. But ANN, with performance indices of 95.5% (9.4) and 99.1% (2.6) for Fc and P, respectively, outclassed EPR with 90.3% (13.9) and 97.7% (4.2) performance indices for Fc and P, respectively. Taylor's and variance diagrams were also used to study the behavior of the models for Fc28 and P compared to the measured values. The results show that the ANN and EPR models for Fc28 lie within the RMSE envelop of less than 0.5% and a standard deviation of between 15 MPa and 20 MPa, while the coefficient of determination sector lies between 95% and 99% except for LNR, which lies in the region of less than 80%. In the case of the P models, all the predicted models lie within the RMSE envelop of between 0.5% and 1.0%, a coefficient of determination sector of 95% and above, and a standard deviation between 2.0 and 3.0 points of impact. The variance between measured and modeled values shows that ANN has the best distribution, which agrees with the performance accuracy and fits. Lastly, the ANN learning ability was used to develop a mix design tool used to design sustainable concrete Fc28 based on environmental impact considerations. Doi: 10.28991/CEJ-SP2023-09-03 Full Text: PD
A Review of Advances in Peat Soil Stabilisation Technology: Exploring the Potential of Palm Oil Fuel Ash Geopolymer as a Soil Stabiliser Material
Get PDFThis study aims to highlight the latest developments in the field of peat soil stabilisation technology via chemical stabilisation. The review examines the use of traditional stabilisers such as OPC and various non-traditional stabiliser materials, i.e., Palm Oil Fuel Ash (POFA)-OPC blends, chemical solutions, and geopolymer materials, to enhance the Unconfined Compressive Strength (UCS) characteristics of peat soils based on the ASTM D 4609 requirements. OPC, POFA-OPC blends, and alkaline solutions mostly produced stabilised soil samples that fell short of the ASTM requirements. Existing studies on the use of waste-derived geopolymers to treat peat soils are limited, while the use of POFA geopolymer materials has mostly focused on the improvement of clayey and silty soils. The results of soil stabilisation with geopolymer were very encouraging, as the strength gains were in line with the ASTM soil strength requirements. As a result of this review, it can be concluded that POFA geopolymer is a viable soil stabiliser material with the addition of Ground Granulated Blast Furnace Slag, and that the use of POFA-GGBFS geopolymer to enhance the strength properties of peat soils should be investigated. Doi: 10.28991/CEJ-2023-09-08-017 Full Text: PD
Calibration and Validation of CN Values for Watershed Hydrological Response
Get PDFThe amount of rainfall can be used to estimate the runoff that enters a reservoir. Runoff is influenced by land use, and soil type greatly affects the amount of runoff that will occur. This study discusses the development of a hydrological model with the application of the Hydrologic Engineering Center (HEC-HMS) in the Karangmumus watershed using soil data that has been verified in the field and divided into soil zones based on soil permeability testing in the laboratory. With the help of Geographic Information System (GIS) and Geospatial Hydrological Model (HEC-GeoHMS) applications, it is possible to identify the flow of the Karangmumus watershed and the Lempake Dam in Kalimantan by simulating the rain runoff process. The hydrological model was developed in the HEC-HMS by recording daily rainfall events from 2009 to 2019. With a daily period, then, the zoning soil type data was entered based on the results of soil permeability testing with the help of the application of the soil conservation curve method (SCS-CN), then discharge transformation, and calculation of water loss, including routing with Muskingum and SCS-Hydrograph applications. Based on the distribution of the CN value, the theoretical runoff is calculated and then calibrated with the observed discharge in 2017 and 2018, and then validated with the observed discharge in 2019, showing good results with a coefficient of determination between 0.89 to 0.92. Doi: 10.28991/CEJ-2023-09-01-06 Full Text: PD
Selecting the Safety and Cost Optimized Geo-Stabilization Technique for Soft Clay Slopes
Get PDFSlope failure poses a serious threat to the built environment as it is currently one of the fundamental contributors to climate change fears across the world, and this threatens the environmental goals of the United Nations Sustainable Development Goals (UNSDGs) for the year 2050. In this research paper, an optimized geo-stabilization numerical model has been developed with a Plaxis 2D code under safety and cost optimization considerations for a 37 m high slope embankment located on a soft clay watershed with an infinite extension. The site was prepared with four monitoring wells installed at 2.5 m, 7.5 m, 12.5 m, and 21.5 m from the foot of the slope to measure the water level conditions, and samples were collected and tested in the laboratory to determine the hydraulic and shear strength and modulus of the soil. Seven (7) different simulation alternatives were considered in terms of the model solutions to be deployed under dry and wet states, which were slope steep (angle) reduction (Alt-1), dewatering (Alt-2), jet grouting (Alt-3), jet grouting/dewatering (Alt-4), slope reduction/jet grouting (Alt-5), slope reduction/dewatering (Alt-6), and slope reduction/jet grouting/dewatering (Alt-7). The finite element model implementation of the alternatives showed that Alt-2, Alt-3, and Alt-4 had FOS of less than 1.5 and were omitted because their stability considerations did not meet the requirements for the normal operating conditions of a slope and also the short-term and long-term stability conditions according to the literature. Alternatives 1, 5, 6, and 7 with FOS above 1.5 were selected for further optimization considerations. Economic and sustainability factors were selected and considered based on the cost in line with current average market prices, constructability, reliability, and the environmental impact needed to achieve the required earthwork, jet grouting, dewatering, and selected combinations. Finally, the Alt-1 (FOS = 1.505), though not the cheapest, was selected as the optimal choice in terms of reliability, constructability, and environmental impact. However, Alt-6 (FOS = 1.520) and Alt-7 (FOS = 1.508) are the most economical but ranked low in reliability and environmental impact considerations. Doi: 10.28991/CEJ-2023-09-02-015 Full Text: PD
Performance Evaluation of Fiber-reinforced Ferroconcrete using Response Surface Methodology
Get PDFFibre-reinforced ferroconcrete is a new-generation type of concrete that has been found to have adequate performance. Global emissions of CO2 as a result of concrete production have damaged the earth's atmosphere. These emissions, together with construction waste, such as ceramic powder and aluminium waste, are considered one of the most harmful wastes to the environment, eventually leading to pollution. In this study, the fibre-reinforced ferroconcrete (FRFC) contained waste aluminium fibre, cement, ceramic waste powder, corrugated wire mesh, and fine and coarse aggregate. The cement content in the concrete mix was partially replaced with Ceramic Powder (CP) in proportions of 0%, 10%, and 20%, while the Aluminum Fibers (AF) were added in proportions 0, 1, and 2% to the concrete mix. The variation of ceramic powder and aluminium fibres was done using the central composite design of Response Surface Methodology (RSM) to create experimental design points meant to improve the fibre-reinforced ferroconcrete's mechanical performance. The results conclude that the mechanical performance of the FRFC was slightly improved more than conventional concrete, where at 20% replacement of ceramic powder and 1% addition of aluminium fibre to the concrete mix. There was more compressive, flexural, and split tensile strength increase than conventional concrete, with control concrete having strengths of 13.060, 5.720, and 3.110 N/mm2 and ferroconcrete 15.88, 6.68, and 3.83 N/mm2 respectively. This was further confirmed with microstructural images. The RSM model, with parameters such as; contour plots, analysis of variance, and optimisation, was used to effectively predict and optimise the responses of the ferroconcrete based on the independent variables (Aluminum fibre and Ceramic Powder) considered. The results of the predicted data show a straight-line linear progression as the coefficient of determination (R2) tends to 1, indicating that the RSM model is suitable for predicting the response of the variables on the FRFC. Doi: 10.28991/CEJ-2023-09-04-014 Full Text: PD
Neutralization of Acidity (pH) and Reduction of Total Suspended Solids (TSS) by Solar-Powered Electrocoagulation System
Get PDFThis study investigates the effect of electrocoagulation contact time on the pH and TSS of wastewater discharged from the wastewater treatment plant (WWTP) of the Psychiatric Hospital of West Java Province. The experiment followed the pretest-posttest control group design. This study involved testing 56 wastewater samples six times before and after treatment. Each treatment was repeated four times, and there was one control group for each repetition. The electrocoagulation tool used in this study consisted of six 1-mm electrode plates that were 8 cm apart, a current strength of 5A, a voltage of 12V, and a 50-Watt solar panel. The data were analyzed using descriptive and inferential statistics. The results showed that all electrocoagulation contact time treatments had a significant effect on increasing the pH and the TSS. Additionally, the electrocoagulation tool was found to be effective, stable, portable, and environmentally friendly, with a self-cleaning system that reduced operational costs and saved electricity through the use of solar panels. This study contributes to the development of an effective electrocoagulation toll for wastewater treatment and the determination of the optimal contact time for the tool, providing a practical solution to overcome the problems of pH and TSS in wastewater. These findings can be applied to other wastewater treatment plants, thus improving the quality of discharged wastewater. Doi: 10.28991/CEJ-2023-09-05-09 Full Text: PD