CTU Journal of Innovation and Sustainable Development

Production of dicalcium phosphate anhydrous from the bone of Nile Tilapia (Oreochromis niloticus) grown in Viet Nam

Tue, 04 Mar 2025 00:00:00 +0700

This study was conducted to find a facile method for preparing dicalcium phosphate anhydrous (DCPA) from the bones of Nile Tilapia, recovered from a by-product of the fillet process. The by-product containing bones of the Nile Tilapia collected from a local factory was stewed in boiling water and treated with NaOH solution to remove organic impurities from the obtained bones of Tilapia. The pre-treated bones were then calcined and ground to a fine powder before converting to dicalcium phosphate anhydrous. The factors affecting the yield of DCPA such as precipitation pH, reaction temperature, and reaction time were investigated. Modern analytical methods, such as XRD, SEM, XRF, and TGA were employed to characterize the DCPA. The DCPA product with high crystallinity (~ 98.5%) with particle sizes ranging from 1 to 3 µm was obtained at pH 5, 90 min. reaction, and 80°C. This study showed a facile and viable method for producing dicalcium phosphate anhydrous from the bones of Nile Tilapia.

Influence of Limestone Powder Particle Size and Content on Portland Cement Paste Properties

Cheng-Xuan Yu, Wei-Chien Wang, Hoang-Trung-Hieu Duong, Jia-Chen Xue — Tue, 04 Mar 2025 00:00:00 +0700

The purpose of this study was to investigate the effects of different particle sizes and contents of limestone powder (LSP) on the compressive strength and workability of ordinary Portland cement (OPC) paste. Three types of LSP with different specific surface areas (SSA) were used to replace OPC in proportions ranging from 0 to 40%. Both compressive strength and flow experiments were conducted, and the results were analyzed using regression analysis. The findings were further corroborated by X-ray diffraction analysis. The experimental results show that the higher the SSA and the smaller the particle size, the worse the workability. Notably, when the content of LSP is less than 20%, the influence of LSP particle size on compressive strength and workability is not significant. However, when it exceeds 20%, the greater the SSA of LSP, the smaller the particle size, and the smaller the reduction in compressive strength. According to the result, the LSP-F has the optimal performance in the higher replacement, especially at the 20% replacement.

Using efficient bimetallic FeCo-ZIFs catalyst for Ciprofloxacin degradation in the presence of potassium peroxydisulfate

Tue, 04 Mar 2025 00:00:00 +0700

Solvothermal synthesis was used for the successful manufacture FeCo-ZIFs bimetallic materials. The materials' properties were determined using a variety of techniques, including Fourier-transform infrared spectroscopy (FT-IR), energy dispersive X-ray spectroscopy (EDX), powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and nitrogen adsorption ability. The obtained FeCo-ZIFs were acted as catalysts to remove Ciprofloxacin in aqueous media with high efficiency. It showed that the decomposition efficiency of Ciprofloxacin reached 92.1% with a weight of 0.4 g/L FeCo-ZIFs, and 0.3 g/L potassium peroxydisulfate for 30 min at room temperature (30±2^oC). According to research, this is the first time FeCo-ZIFs was applied to treat Ciprofloxacin.

Recycling used coffee grounds as fine aggregate in alkali-activated lightweight non-load-bearing composites

Tue, 04 Mar 2025 00:00:00 +0700

Coffee is one of the most consumed drinks, which releases large amounts of used coffee grounds (UCG), causing environmental problems. Thus, UCG was re-used in combination with bottom ash (BA) as fine aggregates in making alkali-activated non-load-bearing lightweight composites (ANLC) in this study. To evaluate the effect of UCG on the properties of ANLC, seven ANLC mixtures with UCG/BA ratios of 0/100, 5/95, 10/90, 15/85, 20/80, 25/75, and 30/70 were prepared. Results showed that the properties of ANLC were influenced significantly by UCG contents. Indeed, an increase in UCG content led to a decrease in dry density, strength, and drying shrinkage while increasing the ANLC’s water absorption, except for the specimen with 5% UCG incorporation. Correlations among properties of ANLC were established and the potential applications of ANLC in real practice were also suggested, proving that the ANLC could be applied to non-load-bearing elements. Among the mixtures, the 28-day ANLC specimen containing 5% UCG exhibited the highest flexural and compressive strengths of 7.12 MPa and 39.4 MPa, respectively, and the lowest water absorption of 10.29% with the relatively low dry density of 1671 kg/m³, indicating the feasibility of using UCG as fine aggregate in the production and application of ANLC.

Optimal location and size of electric vehicle charging and discharging stations in distribution networks with integrated distributed generations

Vo Minh Thien, Tran Thi Lan Anh, Nguyen Quang Ai, Tran Trung Khanh, Vo Ngoc Dieu — Tue, 04 Mar 2025 00:00:00 +0700

Nowadays, the world is moving towards green energy vehicles and electric vehicles (EVs) are one of the chosen solutions. Vehicle-to-grid (V2G) technology is gradually gaining attention to support issues of performance optimization, energy fluctuations, reducing grid operating costs and bringing optimal efficiency to owners. Along with the rapid increase in the number of EVs, the deployment of effective electric vehicle charging station (EVCS) infrastructure is desirable. However, improper installation can cause many negative impacts on the grid and vice versa, especially EVCS applying V2G charging and discharging techniques. In this study, we propose a computational model to determine the optimal location and size of EVCS applying V2G technique in a distribution network integrating distributed generation sources (DG) with the goal of minimizing active power loss, using an improved method combining the firefly algorithm with the quantum-inspired evolutionary algorithm (QBFA) to find solutions for the problem. The solution results are simulated on a 33-node IEEE standard distribution network using Matlab software and compared with the original FA algorithm to evaluate and propose computational solutions to develop the EVCS system infrastructure in practice.

Short-term active power forecasting for wind farms using artificial neural networks

Dinh Thanh Hai, Tran Trung Tinh, Do Nguyen Duy Phuong — Tue, 04 Mar 2025 00:00:00 +0700

These days, wind energy plays an increasingly crucial role in the energy sector, posing challenges in its management and operation. Given the current upgrade of Vietnam's 500 kV grid infrastructure, wind farms are concentrated in specific regions. This concentration can lead to significant power influxes into the grid at certain times, causing grid overcurrent. Hence, the National Load Dispatch Center is currently regulating power generation based on forecasted data from generating units. Therefore, short-term power forecasting for wind farms is crucial to mitigate grid overcurrent. This article proposes a short-term forecast of active power in wind farm using a model based on Artificial Neural Network (ANN) on Matlab platform. In the process of building the ANN model, this article considers eliminating the impact of capacity regulation on the power grid. The model was tested using real data from the Ia Pết Đăk Đoa 1 wind farm in Gia Lai province. The time forecast is given in 15-minute intervals for the next 4 hours. The collected results show the superiority of the method in forecasting with low errors and saving calculation time.

A feasible process for recycling anthocyanins and pectin from the waste peels of purple passion fruit (Passiflora edulis Sims) as food additives

Tue, 04 Mar 2025 00:00:00 +0700

Purple passion fruit is widely cultivated in Vietnam and its peels are considered by-products or agricultural waste after processing, which could cause environmental issues. Notably, these peels contain some valuable components with high bioactivities and applicability, such as anthocyanins (natural colorants) and pectin. Therefore, this work proposes a process for the sequential recycling of anthocyanins and pectin from purple passion fruit waste, in which anthocyanin extraction conditions and their bioactivity by ultrasound-assisted solvent extraction were studied and the characteristics of the obtained pectin were analyzed. The results showed that approximately 95% anthocyanins (125.4 mg/100 g dried peels) were extracted under the best conditions such as 80% ethanol (v/v), 1:25 (g/mL) solid/liquid ratio, 40°C incubation temperature, and 10 minutes sonication time. The findings demonstrated the antioxidant and cytotoxic activity of KB epithelial cells of the anthocyanin extract. Additionally, 7.47% of pectin from the residues after extraction anthocyanins were extracted by citric acid with pH 2 at 87°C for 90 minutes. The pectin has 68.34% purity, and 57.14% of DE, and its structure was confirmed by FT-IR spectra. This study can be utilized to recover useful components from purple passion fruit peel waste, improving the fruit’s value and reducing the environmental impacts of its peels.

Multi-Quality Optimization in Pulsed Laser Cutting of Thin Laminated Cores Using the Preference Selection Index Method

Tue, 04 Mar 2025 00:00:00 +0700

This study explores a pulsed Nd:YAG laser cutting of thin laminated cores made from non-oriented electrical steel sheets, aiming to optimize cutting quality aims to investigate the cutting quality of a thin laminated core using a non-oriented electrical steel sheet by a pulsed fiber Nd: YAG laser. The influence of laser power (P), scanning speed (v), and pulse repetition rate (f) on cutting time (T_C), recast layer height (H), and kerf surface roughness (S_a) is analyzed to determine optimal processing parameters. Each process parameter is elected with three levels, and a total of 27 experimental datasets are achieved. The preference selection index (PSI) method is used to determine the optimal cutting quality based on multiple criteria derived from experimental results. The best quality is found at No. 23 with process parameters of P = 18 W, v = 600 mm/s, and f = 30 kHz for qualities of T_C = 20.6 s, H = 20.2 µm, and Sa = 2.4 µm.

Effect of extraction solvents on yield, chemical composition and antioxidant activity of Peperomia pellucida (L.) Kunth seed extract

Tue, 04 Mar 2025 00:00:00 +0700

Peperomia pellucida (L.) Kunth is a valuable herbal plant with numerous medicinal properties, offering potential for the development of herbal products with antioxidant benefits. Extraction is a critical step in the recovery and analysis of bioactive compounds in botanical materials. The judicious selection of extraction methodologies and solvents is important in ensuring the recovery and protection of the biological efficacy of these compounds, thereby facilitating the standardization of herbal products. This study investigates the influence of solvent on the yield, chemical composition, and antioxidative activity of P. Pellucida seed extract. The results underscore a propensity towards maximal yield with ethanol employment. Furthermore, all extracts manifest a moderate antioxidative capacity, with the ethyl acetate extract particularly demonstrating heightened activity. Dill apiol is identified as the predominant constituent in all extracts, constituting up to 83% of the composition. The study's findings suggest the promising potential of P. Pellucida seed extract as a valuable source of antioxidants, paving the way for the creation of beneficial herbal products.

Simulation of flow velocity variations in the Cai Khe Channel during sluice gate operation

Dinh Van Duy, Nguyen Hoang Phuc — Tue, 04 Mar 2025 00:00:00 +0700

The three-dimensional hydraulic model Flow-3D was used to simulate the flow velocity in the Cai Khe channel when operating the gates of the Cai Khe barrier. Primary and secondary data were collected to build, calibrate, and validate the model. The NSE coefficient for calibration and validation cases were 0.74 and 0.61, respectively, indicating the reliability of the model. The case of operating the gate to discharge pollutants and create a unidirectional flow with a water level difference between the field and the river of 1.54 meters was chosen to check for potential erosion. The simulation results showed that at profiles 1 and 2 (located 10 meters and 60 meters from the center of the sluice towards the river, respectively), the average flow velocities were 2.97 m/s and 4.99 m/s, respectively, which are greater than the allowable non-erosive velocity (v_x = 0.19 – 0.26 m/s). Therefore, the riverbed needs to be reinforced to prevent erosion when operating the sluice gates.

Impact of recycled concrete aggregate particle size on the strength of soil mixtures for subgrade improvement

Ho Thi Kim Thoa, Le Hoang Khanh — Tue, 04 Mar 2025 00:00:00 +0700

Subgrade improvement applications have extensively investigated the financial and ecological benefits of utilizing recycled concrete aggregate (RCA) waste. This solution has been widely studied in recent decades. This study presents the findings of the relationship between different sizes of recycled concrete aggregate (RCA) particles and certain properties of SRCA blends by adding cement. The test results showed that adding RCA with cement to unstabilized soil significantly improved its compressive strength behavior. Incorporating RCA into the soil mixture can more than double its compressive strength. Integrating larger RCA particle sizes into unstabilized soil decreased the optimum moisture content (OMC) while increasing the maximum dry density (MDD). Conversely, using finer RCA particle sizes in soil mixtures increased the compressive strength compared to larger RCA particles. This blend of RCA-stabilized expansive soil is suitable for subgrade improvement applications, such as building low-traffic volume roads and ensuring embankment stability.

Digital mapping of soil electrical conductivity for paddy field

Ho The Anh, Luu Trong Hieu, Nguyen Chi Ngon — Tue, 04 Mar 2025 00:00:00 +0700

The digital soil electrical conductivity (EC) map has been widely applied in agriculture globally due to its ability to explain various soil characteristics. However, the Mekong Delta lacks comprehensive data on soil EC. This study aims to address this gap by using the common interpolation method —K-Nearest Neighbors (KNN), Inverse Distance Weighting (IDW), Kriging interpolation, and Convolutional Neural Networks (CNN)—to map soil EC over an area of approximately 1.4 hectares. Using 228 data samples, the study found that the Gaussian model within Kriging was the most effective for interpolating soil EC, achieving the highest R-squared values (0.79 with test data and 0.96 with full data) and the lowest RMSE values (0.049 with test data and 0.022 with full data). Additionally, GPS data collection using the U-blox ZED-F9P-01B GPS module, paired with the U-blox ANN-MB-00 antenna, yielded better accuracy and reliability under rice field conditions (Q=1) compared to the performance in orchard settings. This research provides valuable insights into soil management and agricultural practices in the Mekong Delta.

Investigating effects of cutting parameters on surface roughness machined by turning of C45 steel based on Taguchi methodology and ANOVA

Tue, 04 Mar 2025 00:00:00 +0700

The present study investigates the effects of cutting parameters (cutting speed, feed rate, and depth of cut) on the roughness of the finished surface during turning C45 steel using CNC QUICK TURN 150 SG (Mazak, Japan) with carbide inserts WNMG431PP CA525 (Kyocera Precision Tools TAC08616). The experiment design was based on the Taguchi method. The results show that the feed rate significantly influences surface roughness; the cutting velocity is second in order, and the depth of cut is the weakest influence parameter on the surface roughness. The regression equation was proposed to predict the roughness of turned surfaces and its determination coefficient ( ) of 0.9985. The prediction predicted by the regression models is compared to the experiment. The mean absolute and square error values are 6.73% and 0.85%. Hence, the model is reliable in estimating surface roughness.