română R. KARIMIA, I. ABBASPOURA, M. AMIRIB
Abstract
Magnetic Nanofluids, such as water-alumina, water-copper, and water-iron oxide, have been attracted due to their interesting thermo physical properties and their application are important branches of engineering such as heat transfer. Research results in recent years show that the presence of nanoparticles increases heat transfer. In this research, we will produce iron oxide (Fe3O4) nanoparticles, by co-precipitation. Two samples of nanoparticles were synthesized, and the size of the produced nanoparticles was around 30-60 nm. The size of the nanoparticles in the fluid (water) and their distribution have a significant effect on the conductivity coefficient of the porous medium (magnetic Nanofluid). Therefore on the heat transfer factor, we will try to reduce the size of the nanoparticles as much as possible and make the particle size distribution uniform. After synthesis, nanofluid is obtained by combining nanoparticles with a certain mass with water. Arabic gum has been used to prevent nanoparticles from sticking together in nanofluid suspension. Zeta potential was obtained for nanofluid suspensions and it was observed that have good stability. To investigate the effects of adding nanoparticles to water in heat exchangers, we used critical heat flux (CHF) analysis. Using CHF, we can obtain the heat transfer factor, and we showed that by adding synthesized Fe 3 O 4 nanoparticles to the base fluid, the heat transfer is improved.
Keywords
Nanofluids, Heat transfer factor, Iron (II, III) oxide, Heat exchangers
DENISA-NICOLETA MUȘAT, ALEXANDRA-CRISTINA BURDUȘEL, ȘTEFAN GAFTONIANU, ANTON FICAI, OVIDIU OPREA, ROXANA POPESCU, ROXANA TRUȘCĂ, ECATERINA ANDRONESCU
Abstract
This research describes the synthesis and characterization of a nanocomposite material that serves dual purposes: promoting bone healing and providing microbial defense. Therefore, 45S5 bioactive glass was synthesized through sol-gel synthesis with zinc oxide nanoparticles produced via microwave-assisted hydrothermal synthesis. The addition of peppermint and lemon balm essential oils at different concentration levels enhanced the material’s biological functionality. The composites considered were analyzed by thermal analysis (TG–DSC), FTIR spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS) for evaluation. The analysis confirmed the existence of crystalline phases, along with particle morphologies and the incorporation of functional groups. The bioglass particles measured between 2–4 μm in size, while the ZnO nanoparticles size range was from 200 to 400 nm, with a uniform distribution confirmed by elemental mapping. The biocompatibility assessment utilized an MTT assay with MG-63 osteoblast-like cells. The results showed that ZnO caused dose-dependent cytotoxicity; however, the addition of essential oil reduced this effect, mainly when lemon balm essential oil was used at a 2% concentration, which demonstrated improved biocompatibility across all tested concentrations. The developed composite material exhibits enhanced antimicrobial properties and osteoconductivity, along with reduced cytotoxicity, making it suitable for biomedical applications in bone tissue engineering.
Keywords
bioglass, zinc oxide, composite, essential oils, antimicrobial effect
ANDREEA-CRISTIANA ALEXE, ALEXANDRA-CRISTINA BURDUȘEL, ȘTEFAN GAFTONIANU, OVIDIU OPREA, ROXANA POPESCU, ROXANA TRUȘCĂ, ANTON FICAI, ECATERINA ANDRONESCU
Abstract
Bone tissue regeneration presents a significant challenge due to the complexity of bone structures and the limitations inherent in traditional grafting methods. The aim of the study is to describe the development and analysis of a nanocomposite material that combines cerium-doped hydroxyapatite (Ce-HAp) with bioactive glass (45S5 Bioglass) and natural essential oils (sage and thyme). The hydroxyapatite was produced through microwave-assisted hydrothermal synthesis, the bioglass through sol-gel processing, and essential oils were added to the final obtained material. The composite material underwent XRD, FTIR, SEM, and EDAX analysis, which confirmed its crystalline phases, chemical composition, and morphological features. The MTT assay results showed that MG-63 osteoblast-like cells demonstrated high biocompatibility and no cytotoxicity, while samples containing sage essential oil led to increased cell viability. The thermal analysis showed that the composite materials maintained excellent thermal stability. The nanocomposite material exhibits enhanced bioactivity, antimicrobial properties, and cytocompatibility, making it suitable for medical applications. The multifunctional system provides a substitute for standard grafts, while additional biomedical applications can be achieved by adding biologically active ions such as Ag, Sr, Ce, or Zn.
Keywords
hidroxiapatită, oxid de ceriu, uleiuri esențiale, biosticlă, biocompatibilitate
PERFORMANCE OF TITANIUM GYPSUM-REPLACED MAGNESIUM CHLORIDE-MAGNESIUM OXYCHLORIDE COMPOSITE MATERIALS
SHUREN WANG, LINRU ZHAO, JIAN GONG, YAN WANG
Abstract
To realize the resourceful utilization of solid waste and develop novel building materials, an experimental study was conducted using titanium gypsum, magnesium chloride, and magnesium oxide as raw materials to prepare test samples. The samples underwent a series of tests, including unconfined compressive strength testing, water absorption analysis, dynamic non-contact full-field strain measurement, scanning electron microscopy, and X-ray diffraction, to investigate the effects of varying titanium gypsum substitution rates for magnesium chloride on the strength, failure modes, and microstructural properties of the resulting composite materials. Results show that as the substitution rate of titanium gypsum increases, the dry density of the composites initially increases and then decreases, while the water absorption rate continues to rise, with a particularly notable increase observed at substitution rates between 10% and 25%. Both flexural and compressive strengths exhibit an initial increase followed by a decrease, reaching their optimal values at a 5% substitution rate, with a maximum improvement of 17.37% in flexural strength and 18.81% in compressive strength. The increase in titanium gypsum substitution rate alters the phase morphology and internal density of the composites, confirming the feasibility of substituting magnesium chloride with titanium gypsum in magnesium oxychloride cement. This substitution strategy not only promotes the utilization of solid waste but also contributes to cost savings, highlighting its potential for practical applications.
Keywords
magnesium oxychloride cement, titanium gypsum, mechanical properties, microstructural analysis
DAVID RESANO, JOSE BARRANZUELA, FABIOLA UBILLÚS, OSCAR GUILLEN, ANA GALARZA
Abstract
High-altitude human settlements, such as those in the Andes and the Himalayas, experience extreme temperature conditions, yet many houses in the Peruvian Andes lack thermal insulation due to the unavailability of affordable materials. As a result, respiratory diseases linked to low temperatures are widespread during the coldest months of the year. This study presents the development of an innovative thermal insulation panel made from locally sourced sugarcane bagasse fibers, bonded with polyvinyl acetate and fabricated using compression molding. The panel achieved a thermal conductivity of 0.043 W/m·K, which allows compliance with Peruvian thermal transmittance standards when applied in layers of approximately 6 cm thickness. The material exhibited a bulk density ranging from 86.7 to 105.3 kg/m³. Mechanical testing showed a low average tensile strength of 0.0144 kg/cm² and a flexural modulus of 0.116 kg/cm², indicating that the panel is not suitable for structural applications. However, it is effective as a non-structural thermal insulation solution. The proposed panel promotes a circular economy by repurposing agricultural by-product and offers a low-cost, biodegradable alternative to synthetic and mineral fiber insulations, contributing to reduce material costs and environmental impact in buildings.
Keywords
Composite, organic material, sugarcane bagasse fibers, thermal insulation, circular economy
MANI P, ARULARASAN R
Abstract
One of the biggest obstacles to using natural fibers in industrial applications is their poor mechanical qualities. The study aims to use carbon and glass fillers to increase the flexural, impact, and tensile strengths of luffa/epoxy composites. Three fillers proportions (5wt.%, 7.5wt.%, 10wt.%) and one luffa proportion (20wt.%) were taken to fabricate the composites. The ASTM guidelines were followed when conducting the experiments. The fillers enhanced the composites tensile, flexural, and impact strengths. Comparing carbon-filled composites to corresponding glass-filled composites, the former showed superior performance. The 7.5wt.% carbon-filled composite shows the highest tensile and impact strength values, whereas the composite without fillers shows the lowest tensile and impact strength values. For flexural strength, 10wt.% carbon-filled composite shows the highest values, whereas the composite without fillers shows the lowest values.
Keywords
luffa fiber, carbon filler, glass filler, tensile strength, impact strength, flexural strength
J.JEGAN, P.ANITHA, SUNANTHA B., J SUDHAKUMAR, R.LOGARAJA, KONA PRAVALLIKA PHANI DURGA
Abstract
Phase-change materials must now be used during construction to reduce greenhouse gas emissions and boost energy efficiency. Considering concrete makes up the majority of construction materials worldwide, incorporating PCMs into concrete can greatly increase a structures energy efficiency. There has been a growing interest in phase change materials (PCMs) in recent years. By utilizing the appropriate PCM and integration approach, the majority of issues associated with utilizing PCM in concrete may be resolved. In this work, Thermal Storage Light Weight Aggregate (TSLWA) was produced by incorporating pumice stone into Paraffin wax. The concrete cube were cast with different replacement ratios of TSLWA with LWA such as 0%, 25%, 50%, 75%, and 100%. The study revealed that increasing PCM content reduced water absorption, with the control sample absorbing 8.5% water compared to only 1.8% for the 100% PCM sample. Compressive strength decreased with higher PCM percentages, with the 100% PCM sample showing significant reduction, emphasizing the need for a balance between thermal properties and structural integrity. Thermal analysis showed that paraffin wax exhibited thermal transitions around 50°C, demonstrating stable thermal behavior up to 300°C. Microstructural examination revealed altered bonding strength due to paraffin wax-filled aggregates, and leakage tests highlighted the effectiveness of epoxy resin coatings in reducing water seepage. Overall, PCM-impregnated pumice concrete improves moisture resistance and thermal performance, offering a promising solution for sustainable construction, though careful consideration of PCM concentration is needed to maintain mechanical strength.
Keywords
thermal storage aggregate, Pumice stone, immersion method, phase change materials, paraffin wax.
A. THOMAS EUCHARIST, V. REVATHI
Abstract
Concrete is one of the most vital building materials next to the water. Day by day, the demand for concrete is escalating with the rising demand for infrastructural development, and the cement industry is one of the dominant contributors to the production of greenhouse gases. So, efforts are essential to make concrete further eco-friendly by adopting cement-free concrete, which helps overcome global warming. In this study, varying compositions of alumina silica materials made up of ground granulated blast furnace slag (GGBFS) and sugarcane bagasse ash (SBA) were supposed to be utilized in the manufacture of geopolymer mortars, and five different ratios of 100:0, 75:25, 50:50, 25:75, 0:100 were proposed. It might be a better solution for both waste disposal problems and issues related to cement production. Combinations of GGBFS and SBA were made with varying concentrations of alkaline solution starting from 10M, 12M, and 14M. The strength properties of the prepared specimens were assessed by conducting compressive strength test on mortar and concrete specimens at 3 days, 7 says, 28 days. Despite the fact that not all of the combinations of the mixes examined had statistically significant results, the test results do suggest that the GGBFS-SBA blend is viable for use in geopolymer. In a 14M geopolymer concrete mix consisting of 100% GGBS, the highest compressive strength of 61 MPa was achieved.
Keywords
Cement-free concrete, Geo polymer mortar, GGBFS, Bagasse ash, Alkaline solution
EUGENIA TANASĂ
Abstract
One extremely promising method for producing hydrogen sustainably and storing energy is the photoelectrochemical (PEC) splitting of water with solar energy. Hematite is a good photoanode material for water splitting because of its advantageous qualities, according to recent study in this area: it is an n-type semiconductor, possesses a band gap appropriate for visible light absorption, exhibits high chemical stability, and is abundantly available on Earth. This review presents various strategies for modifying hematite to enhance its performance. These modifications include element doping, nanostructure design and fabrication, co-catalyst integration, heterostructure formation and the interdependence between the structure and performance of hematite.
Keywords
solar energy, hematite, photoanoes
XIANWU JING, XIAOJIN ZHOU, TENG GONG, TAO WANG, YANG WANG, GUOQING LIU, KAIJUN WANG
Abstract
This research employed molecular dynamics simulations to explore the distribution of sodium dodecyl sulfate (SDS) at the n-hexane/water interface. Once the SDS concentration surpasses the critical micelle concentration(cmc), a large portion of SDS migrates to the n-hexane/water interface, establishing a thin layer where sulfonic acid groups are oriented towards the water phase and carbon-hydrogen chains are directed towards n-hexane, a small amount of SDS forms spherical micelle with sulfonic acid groups facing the water phase, while carbon-hydrogen chains aggregate in the interior of these spherical structures. The sulfonic acid group of SDS forms multiple h-bonds with water, shows strong interaction energy; while the carbon hydrogen chain itself has only weak van der Waals interactions with surrounding molecules. The thickness of SDS- layer at the n-hexane/water interface is about 2.06 nm, with a maximum number density of about 0.25 per nm3, and average area occupied by a single SDS- is about 0.21 nm2. According to radial distribution function (RDF) result, due to the attractive effect of positive and negative charges, the first coordination layer of Na+ ions and oxygen atoms on sulfonic acid groups is about 0.21 nm. This study investigated the distribution of SDS at n-hexane/water interface, vividly demonstrating the mechanism by which SDS reduces the interfacial tension between oil and water, and providing guidance for oilfield development.
Keywords
N-hexane/water interface; Molecular dynamic simulation; Sodium dodecyl sulfate; Weak interaction analysis
S. DHANALAKSHMI, T. JESUDAS, M. PRADEEP KUMAR
Abstract
The objective of this research study is focused to improve the wear resistance of the reinforced Al6063 hybrid metal matrix composite. The secondary particles like Al2O3 /TiO2are used as a reinforcement particle and the samples fabricated using stir casting technique with the base material Al6063 alloy. The fabricated samples were analyzed using Energy Dispersive Spectroscopy (EDS) and Scanning Electron Microscope (SEM) for understanding the potential of fabricated samples. Dry sliding wear test was conducted for the composite samples. The major wear process parameters such as load, sliding distance were considered for analysis work. The reinforcement particles such as Al2O3 /TiO2 also were considered as one of process parameter for wear analysis. The results of Variance of analysis clearly statethat reinforced secondary particles were the most influencing wear process parameter. The validation of desirability function analysis results reveals that the obtained optimal solutions were effectively enhance the wear resistance property for fabricated hybrid metal matrix composite (Al6063/Al2O3 /TiO2).
Keywords
Al 6063, Al2O3 /TiO2, DFA, Wear, RSM.
CHIENTA CHEN, SHINGWEN TSAI
Abstract
The rapid increase in terrain variability, climatic factors, axle load, and traffic volume has significantly affected the performance of asphalt pavements on expressways, particularly in harsh environmental conditions. In some cases, the service life of expressway pavements is far shorter than the expected design time. Certain sections of expressways face pavement failures just one or two years after opening, including cracks, potholes, rutting, and oil flooding. These problems not only disrupt the normal flow of traffic but also substantially increase maintenance and repair costs. This study focuses on diagnosing and addressing the causes of asphalt pavement failures, specifically in Jiangsu Province, China, where various asphalt pavement diseases were reported in 2020. By calculating the porosity of asphalt mixtures, we assess the water permeability, strength, and durability of the materials. Applying Mohr-Coulomb theory, we evaluate the high-temperature shear strength of asphalt mixtures and analyze rutting depth. Our findings indicate that rutting is the primary distress type on expressways in Jiangsu, with a rut depth of [3-8] mm observed in 67% of the total road network. Additionally, the pavement smoothness of expressways remains within a range of 0.5-1m/km for 85% of the highway network. We also analyze lateral and longitudinal fractures, which constitute 97% of repairs, with transverse cracks becoming prevalent after 6 years of service under high axle loads. This suggests the need for early preventive measures within the first 6 years of service to mitigate the development of cracks.
Keywords
asphalt pavement, highway, pavement diagnosis, repair technology, environmental impact, rutting, crack formation, traffic load.
MĂDĂLINA-OANA MIHĂILĂ, DENISA FICAI, OANA DAMIAN, BOGDAN ȘTEFAN VASILE, ALEXANDRA CRISTINA BURDUȘEL, ANDREI PĂDURARU, ECATERINA ANDRONESCU
Abstract
Before discussing innovative materials and nanomaterials for the conservation and restoration of the national archaeological heritage, it is necessary to dentification and characterization of the main raw materials (plastic and non-plastic materials) and auxiliary materials used to obtain the ceramic body (part I) and the decoration on the surface of the sherd: sculptural – simultaneous with shaping and pictorial, monochrome or polychrome, existing on the inner or outer surface of the ceramic pieces. Thus, according to their origin and the way of formation, by sedimentation, thermal processing – sintering and vitrification, which determines the composition, properties, color and degree of refractivity, they are classified into common clays and superior clays, differentiated by the plasticity index, vitrification being influenced by the ratios of the component oxides, by the firing temperatures: low, medium or high and by the types of atmosphere inside the kilns: oxidizing in the case of white, gray and red ceramics or reducing in the case of black ceramics, partial or complete, made in a single phase or two stages.
Keywords
plastic clay, sculptural decoration, polychrome decoration, ceramic engobes, ceramic glazes, the color, coloring oxides, alkaline oxides and alkaline earth oxides.
SALEM MERABTI, LAYACHI GUELMINE, MEZIANE KACI
Abstract
This study investigates the seismic performance of reinforced concrete buildings ranging from 5 to 20 stories using nonlinear static pushover analysis. Four shear wall bracing configurations are considered: L-shaped peripheral walls, central core, double central core, and double peripheral core systems, with wall thicknesses of 15, 20, and 25 cm, all subjected to unidirectional lateral loading. Although these configurations are widely implemented in both moderate and high seismicity regions, few comparative studies have assessed their nonlinear seismic resistance. The results indicate that central core configurations provide superior control of inter-storey drift, with a significant reduction in lateral displacements—up to 48% compared to peripheral wall systems. In contrast, peripheral wall systems exhibit higher drift demands, reaching a maximum of 0.124% for 15 cm thick walls. The analysis also highlights the effectiveness of L-shaped walls in mid-rise buildings, particularly those with wall thicknesses of 20 and 25 cm. The study of deformation mechanisms reveals a concentration of plastic hinges and thus stress in L-shaped wall systems and at beam-wall joint regions.
Keywords
Multi-storey building, Nonlinear pushover analysis, Reinforced concrete shear wall, Inter-storey drift, Shear stress, Overturning moment.
ALI SABERI VARZANEH, MAHMOOD NADERI
Abstract
In concrete design, durability is as vital as strength, especially in aging structures exposed to harsh environmental conditions. Increased permeability over time compromises structural integrity. Polypropylene (PP) fibers help limit cracking, which in turn reduces permeability. Traditionally, assessing permeability requires destructive core sampling. This study introduces a novel approach—the “cylindrical chamber” test—to evaluate permeability directly on structures. Validation of this method confirmed its reliability. Results indicated that incorporating PP fibers reduced permeability in C25, C35, and C45 concretes by 22.5%, 20.2%, and 16.3%, respectively. XRD analysis revealed that PP fibers influenced Ca(OH)₂ crystallization and enhanced C-S-H formation. MIP results showed a 24.5% increase in pore volume and 32.8% rise in pore surface area in C45 concrete with fibers, yet overall permeability declined. This confirms the effectiveness of PP fibers in improving durability without the need for invasive testing.
Keywords
Concrete, durability, Fiber, Strength, Novel method.
KARTHIKEYAN R, PARTHEEBAN P, THOLKAPIYAN.M, SIVAKUMAR, SUGUNA K, GAAYATHRI KK
Abstract
This work discusses the outcome of Finite Element Analysis using ANSYS Workbench, to analyse the cyclic behavior of rubberized concrete beams with steel fiber reinforcement. The investigation focuses on substituting coarse aggregate with sand coated rubber shreds, obtained from waste conveyor belt, with the sand coating applied using resin. The study examines rubber shreds in proportion of 2.5%, 5% and 7.5%, combined with steel fibres at volume fraction of 0.5% and 1%, total of seven beams were cast and tested under cyclic loading in a standard loading frame of 500kN capacity. The FEA outcomes revealed that reinforced concrete beams with steel fibres and sand coated rubber shreds reveal boosted cyclic efficiency regarding number of cycle’s sustained, maximum deflection and total energy absorption capacity. Load – deflection curves were plotted to compare experimental and FEA for all seven beams. These results have proved very helpful for better understanding the rubberized concrete with fiber reinforcement under cyclic loading, for its use in structural applications.
Keywords
Sand Coated Rubber Shreds, Ultimate Deflection, Steel fiber, Energy Absorption , and Load-Deflection Curve.
ZHI LI, PING JIANG
Abstract
To address the performance limitations of single silica (SiO2) encapsulated phase change materials, a novel shape-stable composite microencapsulated phase change material (CA/CS/SiO2 MEPCM) was prepared using the sol-gel method. Capric acid (CA) was used as the phase change material (PCM), while chitosan/silica (CS/SiO2) served as the composite encapsulation material. Fourier transform near infrared spectroscopy (FT-NIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) were employed to characterize the chemical structure, crystalline phase, and microstructure of the CA/CS/SiO2 MEPCM. The thermal storage properties and thermal stability of the MEPCM were analyzed using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). SEM results indicated that CA was effectively encapsulated within the CS/SiO2 shell, and the reticulated structure of the shell contributed to the high shape stability of the MEPCM. The results demonstrate that CA is effectively encapsulated within the CS/SiO2 shell, and the network structure of the shell significantly enhances the shape stability of the MEPCM. The encapsulation process preserves the chemical integrity of CA, as no structural changes were observed. The synthesized MEPCM exhibits excellent sealing performance at 102 °C, and the thermal stability of the CS/SiO2 composite shell surpasses that of conventional single-shell structures. Furthermore, the material displays a moderate phase transition temperature and a maximum latent heat of 69.38 J/g, meeting the requirements for variable thermal regulation. In conclusion, the CA/CS/SiO2 MEPCM developed in this study is a green, non-toxic, and structurally stable phase change material with a tunable phase transition temperature, offering promising potential for sustainable thermal energy storage applications.
Keywords
capric acid, chitosan, silicon dioxide, microencapsulated phase change materials
SALEM MERABTI, KACI MEZIANE, SLIM ROUABAH
Abstract
This study proposes a robust modeling approach for predicting the drying shrinkage of cementitious composites incorporating expanded cork waste, using a multilayer perceptron (MLP) artificial neural network. An original database consisting of 54 experimental samples and 2430 shrinkage measurements representing nine different material formulations with varying cork, sand, and ground granulated blast furnace slag (GGBFS) contents was used for model development. Five key variables describing material composition, curing conditions, and mass loss served as model inputs. After data normalization and rigorous cross-validation, the MLP significantly outperformed a classical second-degree polynomial regression, as evidenced by a coefficient of determination of R² = 0.999 and a mean absolute percentage error below 1%. Sensitivity analysis identified curing age and mass loss as the most influential factors governing shrinkage evolution, ahead of the cement-to-cork ratio, sand, and GGBFS content. These findings underline the suitability of neural network models for capturing the complex, nonlinear behaviors of bio-based cementitious materials and provide valuable insights for optimizing the design of durable, sustainable composites.
Keywords
Waste expanded cork, river sand, Ground granulated blast furnace slag (GGBFS), composite, shrinkage, Artificial neural networks (ANNs)
VISWANATH KRISHNAN, MOHAN EKAMBARAM, VINOTHKUMAR RAVI, SHEEBA RANI SOUNDARAPANDIAN
Abstract
In this study, powdered magnesium and aluminum particles were combined with a smaller quantity of silicon carbide (SiC) particles, and the sintering process was used to form the metal matrix composite (MMC). The specimens were made at three distinct temperatures such as 4500C, 5000C, and 5400C. The addition of silicon carbide to the magnesium and aluminium leads to increase the hardness. Based on the scanning electron microscopy (SEM), a large number of holes were commensurate with the sintered specimen produced at the minimal sintering temperature. The development of pore was significantly reduced at high temperature, and strong metallurgical bonding was also attained. The hardness of the sintered specimen was also raised at high sintering temperatures. When compared to other traditional machining methods, the reason for using spark erosion machining or electric discharge machining (EDM) is to maintain the optimal surface roughness (SR) and increase material removal rate (MRR). An atomic force microscopy (AFM) and SEM examination was carried out specifically to evaluate the surface parameters of the magnalium MMC. The pit and valley surface was observed in the machining surface. Current and voltage played a crucial role in metal removal and surface roughness.
Keywords
Magnalium composite, sintering, powder metallurgy, hardness, spark erosion machining
QIAN HONG, XIAOFENG CHEN, WEIQING YU, XIAOXIAO MA, YANBING WANG, CHONGQING WANG, CHAO LIU
Abstract
Faced with the defects of engineering disturbed slope soil, such as easy erosion and evaporation of water, this paper uses polyvinyl alcohol (PVA) hydrogel as a soil conditioner to improve the water erosion resistance and water retention performance of engineering disturbed slope soil, and studies the vegetation performance and microstructure of modified soil. The results showed that PVA hydrogel changed the soil structure by using its excellent cementation and water holding capacity. PVA hydrogel completely wrapped the soil particles to form the overall structure of network gel, which significantly improved the soil erosion resistance, water stability and water retention capacity of the soil. With the increase of PVA concentration, the soil erosion resistance, water stability and water retention performance are significantly improved. In addition, the effect of increasing PVA concentration on soil vegetation performance shows a trend of first strengthening and then weakening, with the best soil vegetation performance observed when PVA concentration was 3%. The results show that PVA hydrogel has important application value for reducing soil and water loss of engineering disturbed slope and promoting vegetation restoration.
Keywords
disturbed slope, ecological restoration, erosion resistance, water retention performance, vegetation performance
ANGELA GABRIELA PĂUN, ROBERTA-GEANINA MIFTODE, MIHAELA VASILICA MÎNDROIU
Abstract
This paper presents the main findings of our study on the preparation and characterization of polyvinyl alcohol (PVA)-based conductive bio-membranes intended for use as solid polymer electrolytes (SPEs) in smart window applications. The novelty of this research lies in the development of PVA bio-membranes with enhanced ionic and electronic conductivity through the incorporation of lithium perchlorate (LiClO₄) as a lithium-ion (Li⁺) source, as well as functionalization with deoxyribonucleic acid (DNA) and poly(3,4-ethylenedioxythiophene) (PEDOT), the latter introducing electronically conductive pathways. The bio-membranes were characterized by Fourier transform infrared (FTIR) and UV-Vis spectroscopy, along with electrochemical impedance spectroscopy (EIS) to determine their ionic conductivity. The PVA-based bio-membrane exhibiting the highest conductivity was further employed in the assembly of a smart window device, which was evaluated through chronoamperometry, charge density measurements, and UV-Vis spectroscopy. Results demonstrated that the synergistic combination of PEDOT, LiClO₄ and DNA (facilitating ion transport and polymer matrix interaction) led to the formation of mixed ion–electron conductive pathways that support dual charge transport. The electrochromic smart window incorporating the optimized PVA-based bio-membrane exhibited an optical modulation (ΔT) of 22%, with fast switching times of 11 seconds for coloration and 13 seconds for bleaching.
Keywords
Bio-membranes, Electrochromic smart windows, Polyvinyl alcohol, Deoxyribonucleic acid, Ionic conductivity
CHENKANG LIU, SONGLIN YUE
Abstract
Steel fiber reinforced reactive powder concrete (RPC), as a critical material for engineering construction, has garnered significant research interest regarding its mechanical properties. This study investigates the reinforcement mechanism of steel fibers and the dynamic mechanical behavior of RPC. Composite material theory was employed to analyze the steel fiber strengthening and toughening mechanisms. The distribution of steel fibers and the microstructure of the cement matrix were characterized using X-ray computed tomography (CT) scanning and microstructural analysis. Furthermore, dynamic compression experiments were conducted to evaluate the mechanical response of RPC under high-strain-rate conditions. Results indicate that the interfacial bonding properties between steel fibers and the cement matrix substantially influence the mechanical performance of RPC. A uniform, disordered distribution of steel fibers was found to enhance both the isotropy and compressive strength of the composite. The dynamic strength demonstrates a pronounced strain-rate dependency, wherein the dynamic compressive strength and damage severity increase with escalating strain rates. Notably, damage evolution laws during dynamic compression were quantitatively characterized through high-speed camera imaging. These findings provide valuable insights into the reinforcement mechanisms of steel fibers in RPC composites.
Keywords
reactive powder concrete; microscopic characterization; dynamic mechanical properties; steel fiber reinforcement; damage evolution
PREPARATION METHOD OF DIATOM-BASED EARTH AND ZINC OXIDE COMPOSITE HIGH-DENSITY POLYETHYLENE MATERIAL
KUN LU, HAN KONG, YAOWEN ZHANG, JIAXING ZHU, YUANYUAN DING, XIYU HUANG, CHAO ZHANG
Abstract
In order to cope with the increasingly severe environmental nanotechnology problems and energy shortage, the development of green new materials has become an inevitable trend in today society. In this paper, a preparation method and application of diatom-based earth and zinc oxide composite high-density polyethylene material are provided, which belong to the solid adsorbent composition material. Firstly, high-density polyethylene composites were prepared according to a certain proportion of diatom-based earth and zinc oxide and polyethylene. Then, to improve its performance and UV resistance, Tinuvin 770 is added and mixed with a composite polyethylene material in a gear mixer. Subsequently, the twin-screw extruding machine is set to a certain temperature and speed, extruded, and the extrusion is cut into composite pellets using a tray machine. Finally, these composite pellets are injected into the injection molding machine, where the target mold is selected and molded. At the same time, it can be used as a food packaging bag material, which can inhibit the growth of Staphylococcus aureus and E. bacillus, so that it has the minimum UV stabilizer content, which is a cost-effective and high-performance choice, and its ability to block ultraviolet rays is strong, and it can well protect the quality of packaged food.
Keywords
diatom-based, Zinc Oxide, High-Density polyethylene, Tinuvin 770
BALÁZS CSABA-FÜLÖP, DRAGOȘ UNGUREANU, GAVRIL KÖLLÖ, NICOLAE ȚĂRANU, GAVRIL HODA, TUDOR-CRISTIAN PETRESCU
Abstract
This paper investigates the structural performance and durability of in-situ stabilized soils used as foundation layers in low- and medium-traffic roads. Two field case studies from Romania (Mureș and Cluj counties) involved the stabilization of weak clayey subgrades with hydraulic binders, aiming to enhance bearing capacity and long-term behavior. Laboratory and in situ evaluations were performed, including compressive strength tests (RC₇, RC₂₈), Benkelman beam deflections, and freeze–thaw resistance assessments, in accordance with Romanian standards (STAS 10473-1-87, STAS 1709, PD 177, CD 31). Results indicate that properly stabilized soils can reach compressive strengths and stiffness moduli comparable to conventional granular materials. Benkelman deflection values and variability remained within permissible limits for foundation layers, while frost–thaw testing confirmed the materials durability. Structural dimensioning based on PD 177 showed that the stabilized layers can accommodate projected traffic demands (Nc = 0.5 million standard axles) with substantial fatigue margins. The study supports the controlled use of stabilized soils in road construction, enabling the reuse of marginal local materials, reducing reliance on quarry aggregates, and promoting sustainable engineering practices aligned with circular economy principles.
Keywords
soil stabilization, road foundation layers, Benkelman beam deflection, hydraulic binders, sustainable road construction
JEBA JENKIN JEBAMONY, ANUSHA GURURAJAN, KRISHNA PRAKASH ARUNACHALAM
Abstract
The significant environmental impact of cement production, particularly its contribution to CO₂ emissions, has driven the search for sustainable alternatives in the construction industry. Alccofine, a byproduct of ground granulated blast furnace slag, offers a promising solution as a supplementary cementitious material (SCM). This study evaluates the mechanical and durability properties of concrete incorporating alccofine as a partial replacement for cement, emphasizing its potential to enhance sustainability in construction. Alccofine, with its ultra-fine particles and unique chemical composition, improves hydration kinetics and pozzolanic reactions, resulting in better workability, and decreased permeability in concrete. Experimental investigations reveal that up to 30% replacement of cement with alccofine yields enhanced strength without compromising concrete structural integrity. Microstructural analysis highlights the role of alccofine in refining pore structure and promoting the formation of calcium-silicate-hydrate (C-S-H) gel. By utilizing an industrial waste material, this study demonstrates a sustainable approach to mitigating environmental impacts while maintaining high-performance concrete.
Keywords
Alccofine, Ordinary Portland Cement (OPC), cement replacement, compressive strength, fresh properties, CO2 emission
IVANKA DIMITROVA
Abstract
Objective: The heat production and transfer to the dental pulp can result from various dental procedures such as friction during cavity preparation without water cooling, bleaching, applying lasers and exothermic reactions during the setting of calcium silicate cements. Calcium–silicate cements are hydraulic materials. Their setting process is associated with temperature changes in the cement paste. These bioactive materials have a variety of uses in endodontics such as a repair perforation material, retrograde root filling material and pulp preservation material. Calcium–silicate cements such as direct pulp capping agents are in direct contact with exposed vital pulp . Excessive heat production during the setting of these materials could lead to serious irreversible pulpal damage. The aim of this study was to record variations in temperature changes during the setting process of conventional calcium silicate cements. Materials and Methods The subjects of this study are three commercially-available in the dental practice calcium silicate cements: White MTA-Angelus (Angelus, Londrina, Brazil), White ProRoot MTA (Dentsply, Tulsa, Johnson City, TN), BioAggregate (InnovativeBioceramix, Vancouver, Canadа) and one industrial Portland cement..For this study thermovision camera FLIR T620 and the Flir Reporter Professional 2013 software were used.Thermal imaging capture was carried out under the following conditions: Distance from the camera lens to the experimental set -1 meter, Room Temperature – 20 - 22 degrees Celsius.Statistical Analysis The mean values of the data were compared using the Student t test. Results: The maximum average temperatures during the cement hydration process range between 26.20 and 26.80 degrees. The highest rise in temperature peak was observed with Bioagreggate at 3 minutes after starting the setting process and the warming peak after 7 minutes at ProRoot. WMTA Angelus exerts the lowest mean temperature rise. Conclusion: The knowledge of temperature rise during the setting reaction of conventional calcium silicate cements can help the dentist to make the right decision and choice of the type of calcium silicate cements. During the dental cement hydration process a rise in temperature up to 2 degrees was recorded. This difference is considered insignificant in the alteation of dental pulp and hard dental tissue.
Keywords
Calcium-silicate cements, temperature changes, hydration process, direct pulp capping material
TAREK NAADIA, DJAMILA GUECIOUER, YOUCEF GHERNOUTI, MALİKA SABRİA MANSOUR
Abstract
This experimental study focuses on the development of a steel fiber-reinforced self-compacting concrete (SFSCC) incorporating tuff powder as a local mineral addition. Five mixes were evaluated to assess the influence of fiber dosage on both fresh and hardened properties. The incorporation of steel fibers leads to reduced workability and longer flow times but significantly enhances the stability of the mix by minimizing segregation risks. Mechanically, the addition of fibers results in a marked improvement in flexural strength, with gains exceeding 40% at the highest fiber content. Ductility is substantially increased, reflecting a better ability to absorb post-cracking energy. In contrast, compressive strength shows only a moderate increase, around 11%, confirming that the main contribution of fibers lies in flexural behavior and toughness. The porous texture and pozzolanic activity of the tuff promote strong fiber–matrix bonding, contributing to improved cohesion and crack control. Overall, the findings highlight the feasibility of producing a high-performance, ductile, and stable self-compacting concrete using local resources, offering a sustainable and efficient solution for modern construction needs.
Keywords
Steel fibers, Tuf powder, ductility, workability, flexural strength, compressive strength
LARISA PURDEA, CARMEN OTILIA RUSĂNESCU, GIGEL PARASCHIV, SORIN ȘTEFAN BIRIȘ, SABRINA-MARIA BĂLĂNESCU
Abstract
In this paper, we highlighted the research results regarding the physical and chemical characteristics of the ash obtained from the incineration of sewage sludge and its potential use in cement composition. Considering the climate targets set for 2030 and 2050, it is essential for the circular economy to be implemented for as many waste categories as possible. To this end, this study analyses the ash, classified under waste code 19 01 14, obtained from the incineration of municipal and stormwater sewage sludge from Bucharest, with the aim of its use in the cement industry. This paper includes statistical data regarding the amount of sewage sludge generated in certain countries, some experimental results concerning the properties of the sewage sludge ash (SSA) and its impact on the mechanical strengths of cement.
Keywords
sewage sludge ash (SSA), sewage sludge, cement, waste.
PENG ZHANG
Abstract
The intensification of climate change has aggravated the fatigue damage mechanisms of asphalt pavement materials, posing severe challenges to the long-term durability of road infrastructures. At the same time, conventional repair methods often generate high environmental loads, limiting their ecological sustainability. To address these issues, this study develops a fatigue performance evolution model of asphalt mixtures under coupled temperature–moisture conditions, grounded in nonlinear viscoelastic continuous damage (NVECD) theory. Microscopic damage variables and energy dissipation parameters are introduced to achieve high-fidelity simulation of performance degradation during the service life of pavements. Based on this model, an integrated eco-restoration strategy is proposed that combines the molecular penetration mechanism of bio-based rejuvenating agents with the viscosity-reducing effect of warm-mix technology. This composite approach enhances bonding strength, delays microcrack propagation, and reduces repair-related emissions. Furthermore, a full-process experimental system encompassing aging–repair–refatigue cycles is established to validate the model and evaluate the long-term durability of the repair method. Results demonstrate that the deviation between predicted and experimental fatigue damage within 5.00×105 loading cycles remains below 0.023, confirming the model’s predictive accuracy. With the composite restoration method, the fatigue life of aged asphalt mixtures increases from 1.15×105 to 4.05×105 cycles, while the average crack width is controlled to 3.04 μm and the surface roughness Ra is reduced to 1.49. These findings provide both theoretical guidance and practical solutions for the development of climate-resilient and environmentally sustainable road materials.
Keywords
asphalt pavement materials, fatigue performance, climate change adaptation, eco-restoration, nonlinear viscoelastic damage
IOANA ION, CIPRIAN MIHAI MITU, EMANUEL VIRGIL MARINESCU, ANDREI CUCOS, ALINA RUXANDRA CARAMITU
Abstract
This study presents an eco-friendly synthesis route for a novel hybrid hydrogel (HHy) designed for wastewater remediation using dual crosslinking method: freezing–thawing (FT) and gamma irradiation (GIrr). Polyvinyl alcohol (PVA) and carboxymethyl cellulose (CMC) form the polymeric matrix, silver nanoparticles (AgNPs), and AgNPs decorated graphene oxide (AgNPs/GO) are incorporated to enhance adsorption and photocatalytic properties. Methylene blue (MB) dye was employed as a model pollutant to assess improved adsorption performance. The HHy demonstrated significant improvements compared to unmodified Hy for equilibrium adsorption capacity (EAC): 20% increase with HyAgNPs and 130% for HyAgNPs/GO; swelling ratio (SWR) measurement revealed an increase of 6% for HyAgNPs, 109% for HyAgNPs/GO; water content (WCR) had an increase of 1 % for HyAgNPs, 14 % for HyAgNPs/GO compared to unmodified Hy. Thermal analysis revealed that total carbonaceous residue after pyrolysis at 800 ⁰C, reached approximately 20% of the Hy’s mass for HyAg and HyAgNPs/GO. This indicates effective char formation due to the catalytic role of the AgNPs and graphene oxide (GO) as nucleation sites. The study optimizes the design of functional Hy for water treatment, and also proposes a viable end-of-life strategy through controlled pyrolysis. The synergistic effects of CMC, graphene oxide (GO), and AgNPs enhance both the structural and functional performance of the HHy system, positioning this approach as a promising avenue for advanced wastewater treatment technologies.
Keywords
wastewater remediation, hybrid hydrogel, silver nanoparticles, graphene oxide, graphene oxide decorated with silver nanoparticles, methylene blue adsorption
FANG HUO
Abstract
Ankle injuries in martial arts arise from high-intensity impacts and complex torsional loads. To overcome the trade-off between biocompatibility and mechanical strength in conventional repair materials, we designed a nanostructured hydroxyapatite (HA)/polylactic acid (PLA) composite scaffold. Nano-HA particles were synthesized via controlled solid-state milling (average diameter ~80 nm) and uniformly dispersed in a PLA matrix, then fabricated by 3D printing. We employed BET surface area analysis, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) to characterize pore size distribution and HA–PLA interfacial structure. In vitro tests showed that at 15 wt% HA loading, mesenchymal stem cell proliferation increased by 25% at 42 h, Runx2 expression was upregulated by 30% at day 15, and compressive strength reached 6.0 MPa—significantly higher than controls. Finite element modeling revealed that the nanoscale porous architecture effectively redistributes stress and mitigates concentration. These results demonstrate a clear design–microstructure–performance relationship for nanostructured bone repair scaffolds, offering new insights for high-performance materials in sports injury treatment.
Keywords
Ankle Injury, Biomechanical Mechanism, Tissue Engineering, Bone Repair Materials, Sports Injury Repair, Biocompatibility, Mechanical Properties
WEI ZHENG
Abstract
This work presents an optoelectronic study of cobalt-doped nano-TiO2 camouflage films prepared via a non-hydrolytic sol–gel route and examines their suitability for device integration. Photoluminescence (PL) and UV–Vis absorption measurements show that the films possess a tunable bandgap (3.12–3.24 eV) and exhibit a rapid photoconductive response under visible illumination, with a rise time of about 15 ms and a decay time of roughly 25 ms. SEM observations indicate a highly uniform film morphology, and UV aging tests verify that the coatings retain their structural and optical stability in ambient conditions. When these materials are incorporated into prototype thin-film photodetectors, the devices achieve an on/off photocurrent ratio exceeding 10³ and a responsivity of 0.15 A/W at 450 nm, pointing to their practical promise for adaptive optical filters and smart window coatings. In addition, assessment of visual performance shows that nanoscale optical camouflage layers deliver an average increase of 0.91 points in visual impact over conventional materials, underscoring the capacity of nanoscale optical and electronic architectures to reshape graphic design by enabling more dynamic and aesthetically compelling visual experiences.
Keywords
Nanoscale Optical Camouflage Materials, Electronic and Optoelectronic Properties, Nano Titanium Dioxide, Graphic Design Enhancement, Sol-Gel Process
CHUFENG TAO
Abstract
A novel nanoscale optoelectronic imaging platform is presented that leverages quantum-dot–sensitized sensors together with a hybrid clustering strategy to realize ultra-high-speed acquisition and analysis of rapid nanoscale phenomena. By embedding CdSe/ZnS quantum dots into a plasmonic imaging circuit and feeding the sensor output into a modified k-means routine steered by an artificial fish swarm algorithm (AFSA), data redundancy is suppressed and representative keyframes are extracted in real time. Experiments tracking plasmonic nanoparticle motion under pulsed excitation show a 9.96 % rise in clustering accuracy and a 7.44 % increase in recall relative to standard k-means, accompanied by a 0.086 improvement in the silhouette coefficient. Collectively, these results demonstrate concurrent gains in spatial resolution (down to 50 nm) and temporal resolution (sub-microsecond). Demonstrations in in-situ nanomanufacturing quality monitoring and single-molecule bioimaging further illustrate the platform’s applicability across nanoelectronics and optoelectronic systems.
Keywords
Nanoscale Optoelectronics, Ultra-High-Speed Optical Imaging, Nanomaterials in Imaging Technology, Image Processing Algorithms, High-Speed Phenomena Analysis
MARIA ELIZA PUSCASU, CRISTINA BUSUIOC
Abstract
In the recent years, bone has become the second most transplanted tissue at the global level as a result of increased number of accidents, pathologies and prolonged lifetime span. Currently, there are significant limitations in the available materials for the bone tissue transplantation and there is a high demand for the research of suitable substituents. Following the bone composition and intricate architecture, a grafting material with high potential in bone tissue engineering may be obtained. Bioceramics from the system CaO‒MgO‒SiO2 (ex. diopside, akermanite and merwinite) have excellent bioactivity and are similar with hydroxyapatite from biological point of view, having improved mechanical resistance. Considering the complex inner architecture of the bone, one of the most suitable fabrication methods in the bone tissue engineering is 3D printing as this technique facilitates manufacturing of intricate inner structures with a high control on the infill parameters. In this work diopside, akermanite and merwinite based powders were obtained using both sol-gel and combustion methods. All obtain powders were characterized using X-ray diffraction, while diopside and merwinite powders were characterized from morphological point of view by scanning electron microscopy. Further on, the obtained powders were mixed with an organic additive in order to obtain a printable paste with characteristic adequate for robocasting process. A comparison between the impact of the synthesis method in the paste formulation was further assessed. The obtained 3D scaffolds were evaluated from morphological point of view using Scanning Electron Microscopy. The results suggested that the synthesis method plays an important role in the paste formulation for the 3D printing process and that diopside, akermanite and merwinite based scaffold can be successfully obtained by robocasting method.
Keywords
Calcium Magnesium Silicates; Sol-Gel; Combustion; Robocasting, Bone Tissue Engineering
ELENA CHIȚANU, MIRELA MARIA CODESCU, VIRGIL MARINESCU, ISTVAN BORBÁTH
Abstract
Nanomaterials have attracted considerable attention due to their flexible synthesis methods and wide-ranging functional applications. Among these, SiO2 nanoparticles have attracted significant attention owing to their controllable physicochemical properties, which can be precisely engineered for specific biomedical applications. Since its introduction in 1968, the Stöber method—despite undergoing only minor refinements—has remained the most widely adopted approach for the synthesis of nanoscale SiO2. Due to their morphology and particle size, SiO2 nanoparticles are particularly suitable for use in advanced manufacturing techniques such as three-dimensional (3D) printing, especially within biomedical engineering applications, including bone tissue regeneration. In such contexts, SiO2 nanoparticles are typically dispersed in suspensions, where knowledge of their surface charge is essential, as it plays a critical role in governing their aggregation and colloidal stability. However, existing measurement techniques do not permit direct and accurate quantification of surface charge; consequently, this parameter is often indirectly estimated through the determination of zeta potential. This study presents the tetraethyl orthosilicate (TEOS) concentrations influence on the stability of the SiO2 suspensions. The SiO2 nanoparticles were prepared by classic Stöber technique, with spherical uniform geometry and average sizes starting from 152 nm up to 681 nm due to increasing concentration of TEOS. To determine the zeta potential, suspensions containing 0.05 wt.% SiO2 were prepared in solutions with pH values ranging from 1 to 12. Under alkaline conditions (pH 12), the smallest SiO2 nanoparticles exhibited zeta potential values of up to −58.4 mV, indicating that the analysed suspensions were stable in this medium.
Keywords
silica 3D printing, Stöber method, suspensions stability, zeta potential
STARLIN DEVA PRINCE JOHN SAHAYAM, ARUL FRANCO PANIMAYAM, NAVANEETHA KRISHNAN MUTHU NADAR, MICHAEL RAJ FRANCIS
Abstract
Making high-performance hybrid composites from discarded fishnets may improve sustainability. Hand-lay-up is used to blend glass fibre and epoxy resin in the study. ASTM standards were followed to quantify tensile, flexural, and impact force. Multiple acid solutions Hydrochloric Acid (HCL), Sulphuric Acid (H2SO4), Acetic Acid (CH3COOH) applied to nylon fishnets destroyed pollutants and strengthened composite assemblies based on Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray Spectroscopy (EDS) analysis results. Treated consequences demonstrated superior material properties because tensile strengths achieved 50.71 MPa and flexural strengths measured 40.5 MPa while possessing strong impact resistance. A distribution of materials across the hybrid composites along with minimal voids and improved durability made these composites suitable for marine applications which include boat hulls and structural components. Water absorption tests proved excellent resistance capabilities because the composites exhibited low levels of moisture absorption thus maintaining stability when immersed in water. This research dual-purpose project tackles marine pollution and promotes a circular economy via sustainable development by integrating recycled materials into sophisticated composite systems. Chemically modified waste polymers in ecologically friendly engineering applications may improve engineering materials and performance.
Keywords
Sustainable composites, Recycled nylon fishnets, Glass fiber reinforcement, Epoxy resin matrix, Marine pollution mitigation, Mechanical property enhancement
SAID MOHAMED ELAMIN, BENOUMANE SALLAI, YASSINE KHALFI, ALAMI AHMED, BACHIR BOUIADJRA BACHIR, BENOUIS KHEDIDJA, GUELLA SOUFIANE, BELHIA SOUAD
Abstract
Utilization of agricultural waste for construction materials is an emerging pathway for sustainable development. This study examines the valorization of the Washingtonia filifera palm fibers, one of the main agricultural by-products in Algeria, as a reinforcing material for concrete. Various concentrations and optimum conditions of sodium hydroxide (NaOH) solutions were used to extract the fibers, and subsequently tensile characterization was carried out. The fiber undergone at 2% NaOH for 96 hours has been found to have a 225.95 MPa tensile strength and a 7.85 GPa Young’s modulus. Concrete mixtures were made with 0.5%, 1%, and 1.75% palm fibers by weight of cement. According to mechanical testing, the incorporation of fibers resulted in a slight loss of early age compressive strength, mainly due to porosity. However, as the curing age progressed, the strength performance gradually recovered. The compressive strength of 1.75% fiber blend at 28 days was a maximum of 26.79 MPa. Similarly, flexural tensile strength was notably increased as it achieved a value of 5.96 MPa which was nearly 22% higher than the control. The results show that palm fibers can be converted to effective and green reinforcements when treated appropriately, offering benefits to both engineering applications and the environment.
Keywords
Natural fibers, Fiber-reinforced concrete, Alkali treatment, Cement hydration chemistry, Sustainable construction
MOHAMED CHAKIB KHERRABI, MOHAMMED SI-AHMED, AMAR BENYAHIA, MESSAOUD SAIDANI, SAID KENAI
Abstract
Carbon dioxide emissions, natural resources consumption, and inert waste production represent significant challenges in the construction industry. The use of recycled aggregates and supplementary cementitious materials in mortar and concrete offer promising solutions to these issues. This study investigates the combined effect of recycled sand from brick waste and calcined clay-based cement on the behavior of self-compacting mortar (SCM). The novelty of this work lies in assessing both the mechanical performance and the carbon footprint of these alternative materials. Natural sand (NS) was substituted with recycled brick sand (BS) at proportions 10, 20, 30, and 40% by volume, while cement was partially replaced with 10 and 15% by mass of calcined clay (CC). A series of laboratory tests were carried out to evaluate workability, compressive strength, shrinkage, and microstructural properties. The results indicate that the combination of CC and BS decreases workability and shrinkage, increases compressive strength by up to 23%, and improves the microstructure of the mixtures. The mixtures based on BS and CC are the most ecological with a reduction in the carbon footprint and with the eco-mechanical index (EMI) reaching 28% compared to the control mortar.
Keywords
Recycled brick sand, calcined clay, Self-compacting mortar, Compressive strength, shrinkage, Carbon footprint
CICI JENNIFER RAJ J, KUMAR G, BASKAR S
Abstract
This experimental study investigates the feasibility and performance characteristics of incorporating treated rubber industrial wastewater as a sustainable alternative to potable water in concrete production. The research systematically evaluates the mechanical properties and microstructural characteristics of M25 grade concrete with and without rubber industrial waste water (RIWW) using Scanning Electron Microscopy. The study is exclusively dealt with the behaviour of RIWW, with and without admixtures. From the study, it is observed that compressive strength of the concrete using RIWW and admixtures is 25% to 30% greater compared to other concrete only with RIWW. Furthermore, higher replacement levels displayed tiny voids and microcracks, suggesting a small slowdown in hydration, while concretewith potable water had a dense and well-hydrated microstructure with consistent C-S-H gel formation, according to SEM images.
Keywords
Rubber Industrial Water, Compressive Strength, SEM Analysis, CSH gel
KARTHIKEYAN SAMBANDHAM, BASKAR NEELAKANDAN, GANESAN MANICKAM, RAMKUMAR KATHALINGAM
Abstract
Friction welding is an efficient and economical process of joining two similar or dissimilar metals among various welding processes. Now-a-days, the automobile and other industries are using dissimilar metals in a same working area to compensate the problems faced due to temperature and working atmosphere to enhance company’s economy. The material AA6351 and EN353 alloy steel have wide applications in aerospace & automobile industries, are joined with different input parameters like Heating Time (HT), Heating Pressure (HP), Upset Time (UT), Upset Pressure (UP) with constant rotation. These input parameters are ordered using L27 Taguchi Orthogonal Array (OA) to experiment the process. Friction welding is done in KUKA friction welding machine. After experimentation, the responses like temperature, hardness and axial shortening are measured. Using these responses, the optimization is carried out through Grey Relational Analysis (GRA) and the rankings are identified and tabulated to obtain the optimal solutions. Based on rankings, the optimal input parameters are concluded as 18 bar of Heating Pressure (HP), 7 sec of Heating Time (HT), 22 bar of Upset Pressure (UP) and 3 sec of Upset Time (UT). The Field Emission Scanning Electron Microscope (FESEM) analysis is also used to study the Inter-metallic compounds (IMCs).
Keywords
Friction Welding, AA6351, EN353, Grey Relational Analysis, FESEM analysis
GUIZHEN WANG, LINGLONG ZHOU
Abstract
This study explores the seismic reinforcement of coastal buildings through the innovative application of Shape Memory Alloys (SMAs). SMAs, a novel class of functional materials, exhibit unique properties like shape memory effect, superelasticity, and high damping performance, making them ideal for seismic applications. Recognizing the critical role of structural design in a buildings earthquake resistance, this research introduces an SMA-based damper specifically tailored for coastal structures, considering their unique stress profiles and disaster vulnerability. Through experimental and simulation methods, including MATLABs Simulink module, the study compares the seismic responses of conventional coastal building designs with those incorporating the SMA damper. The results reveal that the SMA dampers bilinear restoring force mechanism significantly enhances vibration suppression, offering a promising solution for seismic reinforcement in building construction. This investigation not only contributes to the understanding of SMA materials but also underscores their potential in structural earthquake resilience, marking a significant intersection of material science, engineering, and seismic technology.
Keywords
Shape Memory Alloys (SMAs); Seismic Dampers; Coastal Building Reinforcement; Earthquake Resistant Structures; Superelastic Materials
ANCA MIHAELA MOCANU, ANDREEA IOANA SUSANU
Abstract
The paper explores the domain of digitally fabricated dental prostheses, specifically detailing the application of CAD/CAM (Computer-Aided Design/Computer-Aided Manufacturing) methodologies within the field of restorative dentistry. The research undertakes a thorough examination of the digital fabrication sequence in prosthodontics, which encompasses critical phases such as intraoral/laboratory scanning, CAD modeling, automated milling, and final surface treatment. A significant portion of the work is dedicated to the CEREC system implementation in the chairside clinical environment (i.e., procedures completed within the dental practice). Furthermore, the study includes an assessment of the specialized equipment and the mechanical behavior of three notable restorative biomaterials: Zirconium Dioxide, IPS e.max Ceram Dentin, and Cerasmart. The CEREC system is a computerized system that can be used to design and produce, in a single session, highly accurate, aesthetic, and durable ceramic restorations for small cavities. The dental materials were analyzed both before and after the firing process using infrared absorption spectroscopy (FITR), and the morphology of the samples was highlighted using a high-resolution scanning electron microscope equipped with an EDX detector and thermal analysis (TG-DTG-DTA). The characterization methods were applied to compare the performance of the three materials, with a focus on marginal adaptation, aesthetics, strength, and ease of processing, and to highlight the essential differences between the materials in the context of their use in dental restorations. The results of this study, together with data from the literature, help to understand the interaction of these materials with tissues and also to modify the properties of these materials.
Keywords
ceramic kits, CAD/CAM technique, absorption spectroscopy, scanning electron microscopy, thermal analysis
ANDREI GÎRBOVEANU, ANDREI ZYBACZYNSKI, MUHEEB ALTALEB, DAN PAUL GEORGESCU
Abstract
This article presents arguments that result both from the specialized technical literature but also demonstrated theoretically and through experimental tests by the authors related to the fact that fiber reinforcement also represents a solution to improve the durability of reinforced concrete. Fiber reinforced concrete has particularities that lead to the improvement of transport mechanisms such as permeability or diffusion but also in terms of reducing the level of specific strains as well as the opening of cracks, which influence these transport mechanisms, at the same levels of stress compared to ordinary reinforced concrete. In accordance with research carried out internationally [1] In the case of steel fiber reinforced concrete, corrosion is much less severe compared to continuous steel reinforcement of concrete structures and the degradation of cracked steel fiber reinforced concrete due to fiber corrosion depends on several parameters, such as: crack opening, aggressiveness of environmental conditions and fiber type. The calculations presented in the article indicated that fiber reinforced concrete exhibits a smaller crack opening for the same conditions related to concrete composition or stress level compared to ordinary reinforced concrete. The results of experimental research carried out on prestressed concrete elements in which the transverse reinforcement with stirrups was replaced with fiber reinforcement in the central area of the opening have highlighted a decrease in specific strains for the same stress levels when using fiber reinforcement, which indicates a reduction in microcracking, lower permeability and, implicitly, increased resistance to the penetration of external agents, thus contributing to improved durability.
Keywords
Concrete, fiber reinforcement, environmental conditions, durability, prestressed concrete, stirrups, deformations