Advances in Science and Technology Vol. 175

Abstract: Gyroid structures are one of the most common Triply Periodic Minimal Surfaces (TPMS) with remarkable mechanical properties, including energy absorption and stress distribution. In the current study, the compressive behavior of gyroid structures fabricated through Fused Deposition Modeling (FDM) was investigated. The deformation and failure mechanisms were predicted via extensive simulations using Finite Element Analysis tools. Experimental testing using Acrylonitrile Butadiene Styrene (ABS) specimens was performed on a Universal Testing Machine (UTM), and the results compared with computational data. To predict the compressive strength and optimize the structural parameters, an Artificial Neural Network (ANN) was trained. Results indicate a good match between the experimental and simulation findings, indicating immense potential for these gyroid structures in energy absorption.

Abstract: This study examines the mechanical performance, cost-effectiveness, and environmental impact of steam-cured cementless mortar incorporating stainless steel slag (STS slag) with ground granulated blast furnace slag (GGBFS) and natural gypsum. As the STS replacement ratio increased, flowability decreased by about 15%, while air content remained within acceptable limits. The STS10 mixture retained over 90% of the control’s compressive strength. Life cycle cost (LCC) analysis showed overall cost reductions of 3.6, 7.1%, and cost–benefit (CBA) evaluation yielded positive net present values and internal rates of return exceeding standard discount rates, confirming economic feasibility. Life Cycle Assessment (LCA) indicated continuous decreases in life-cycle CO₂ emissions with higher STS contents, with additional reductions of 4.4% and 8.8% in the construction phase for STS10 and STS20, respectively. Overall, incorporating 10% STS slag under steam curing offers an optimal balance of mechanical performance, economic efficiency, and environmental sustainability.

Abstract: The disposal of waste marble is a severe concern worldwide, as it is non-biodegradable, leading to dumping issues and environmental pollution. An economically feasible solution to this problem is utilizing it in concrete production that will make the environment green, make the construction industry sustainable, fulfil the high demand for concrete, and convert waste into valuable materials. This study investigates experimentally the feasibility of using waste marble as a partial replacement for coarse aggregate in concrete production. The research focused on preparing M30-grade concrete mixes with varying percentages of waste marble aggregate to replace normal coarse aggregate, ranging from 20% to 100%. The study evaluated the fresh properties, compressive strength, and durability of concrete made with waste marble aggregate. The research findings indicate that the optimal outcome was achieved with a 60% replacement of natural coarse aggregate with waste marble coarse aggregate in concrete production. The workability increases as the percentage replacement of coarse aggregate by waste marble aggregate increases, as found by the slump value test. The compressive strength of the mix having 60% replacement of natural aggregate by waste marble aggregate concrete (WMAC-60) is 10.0%, 11.8% and 12.14, higher than conventional concrete tested at 7, 28, and 56 days, respectively. The durability of WMAC-60 is also improved, with 7.14% and 13% lower chloride ion pass than conventional concrete at 28 and 180 days of a rapid chloride penetration test, respectively. A 6.1% and 6.67% higher resistivity was found in WMAC-60 compared to the conventional concrete at 28 and 180 days of electrical resistivity test, respectively. In brief, waste marble aggregate is an eco-friendly and sustainable method that reduces concrete costs without compromising concrete performance.

Abstract: This study evaluates the effectiveness of EDIPA, an alkanolamine admixture, in improving the early age strength and durability of GGBFS blended mortars under low temperature (5°C) curing. The experimental program comprised compressive strength tests, SEM/XRD analyses, and durability assessments via accelerated carbonation and drying shrinkage. Mortars with EDIPA achieved higher early age and 28 day strengths and exhibited a denser, more refined hydration microstructure. Durability also improved, as evidenced by reduced carbonation depth and lower shrinkage strain. These results indicate that a low dosage EDIPA approach is effective for securing structural performance and durability of mortar in cold weather construction.

Abstract: Rice husk ash (RHA), a waste product of the rice mill, is rich in silica. This study aimed to investigate the use of RHA as a potential adsorbent for the removal of free fatty acid (FFA) from the waste frying oil (WFO). Acid pre-treatment of RH prior to combustion using hydrochloric acid (HCl) was proposed to improve its adsorption performance. The synthesized acid-pretreated RHAs were characterized using Fourier Transformed Infrared (FTIR), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS). It was found that the aRHAs achieved higher silica purity with low levels of organic impurities as compared to untreated RHA. Additionally, aRHAs possessed porous morphology, especially when treated with higher HCl concentration, as revealed by SEM analysis. EDS analysis confirmed the high silica purity with negligible amount of metal impurities for all the RHAs. For adsorption kinetic models and adsorption isotherms, results showed that the intraparticle diffusion model and the Langmuir isotherm gave the best description to the experimental data with the lowest Chi-square values, reported at 0.02 and 5.46, respectively.

Abstract: Magnetized coal fly ash (MCFA) was utilized as a low-cost and eco-friendly adsorbent for the removal of crystal violet (CV) dye from aqueous solution. This study aims to investigate the adsorption behavior of CV onto MCFA through kinetic and isotherm evaluations. The magnetic modification was performed using Fe₃O₄ to enhance the separation efficiency and adsorption performance of raw fly ash. Batch adsorption experiments were conducted to examine the effects of contact time, initial dye concentration, pH, and adsorbent dosage. The kinetic analysis revealed that the adsorption process followed the pseudo-second-order model, suggesting chemisorption as the dominant mechanism. Isotherm modeling showed that the Langmuir model provided the best fit, indicating monolayer adsorption on a homogeneous surface, with a maximum adsorption capacity (q_m) reflecting the strong affinity of CV toward MCFA. The incorporation of magnetic properties significantly improved the adsorbent’s recovery and reusability. Overall, MCFA demonstrated excellent potential as a cost-effective magnetic adsorbent for the remediation of dye-contaminated wastewater.

Abstract: Regenerating cellulose (cotton) through anti-solvent precipitation is a promising method for recycling textile waste. The selection of an anti-solvent during the regeneration of cellulose depends on its molecular structure. In this study, dissolved cotton in dimethyl sulfoxide (DMSO) was treated with five different anti-solvents for cellulose: sodium hydroxide (NaOH), hydrochloric acid (HCl), calcium chloride (CaCl₂) solution, ethanol, and water. The results show that water is adequate in regenerating cotton by up to 20%. The FTIR study was performed to analyze changes in the chemical structure of regenerated cotton following regeneration with different solvents. The C-H bend peak observed around 800-900 cm-1 confirmed that the main β-glycosidic bonds in cellulose were retained across all samples after the regeneration process. Each anti-solvent altered the cellulose structure by modifying hydrogen bonding through specific rearrangements in the chain packing. This is reflected in the lateral-order index (LOI), which represents the ratio of crystalline to amorphous regions. By comparing the lateral-order index (LOI) A1430/A886 from FTIR peak and UV-vis absorbance, the result confirmed that the ranking of effective regeneration using anti-solvent was H2O > NaOH > CaCl₂, ethanol > HCl.