Porosity Of Material Research Articles

Study of Properties of Water-Dispersion Paint and Varnish Compositions with the Content of Modified Mineral Filler

This article presents the results of research work devoted to improving the characteristics of paint and varnish coatings based on aqueous dispersions of polyacrylates; it is proposed to modify them by introducing mineral raw materials as fillers and hydrated lime, with subsequent processing in a vortex layer apparatus. The introduction of activated diatomite does not cause the deterioration of covering power, adhesion or an increase in the porosity of the paint material. The modification of coatings contributes to an increase in their operational properties, which can be associated with a reduction in the free volume in the composite and the formation of polymer boundary layers with modified physical and chemical properties. The aim of this study is to obtain a water-dispersion paint and varnish composition containing modified diatomite on a polyacrylate basis and, subsequently, study its main physical and mechanical parameters. The work has been carried out by the following method: determination of porosity, adhesion, elasticity and covering power of the control composition; determination of porosity, adhesion, elasticity and covering power of the obtained composites using modified filler; investigation of the influence of radiation on the infrared spectrum of the paint coating surface using a FLIRB620 thermal imager. As a result of this research work, it was noticed that the modification of water dispersions with silica-activated diatomite helps to eliminate the main disadvantages of materials and coatings based on acrylate binders—low water resistance and low physical and mechanical characteristics. The introduction of modified diatomite into water-emulsion paint on an acrylate base does not lead to the deterioration of the main performance characteristics of paint coatings—porosity, adhesion, elasticity and covering.

Influence of Process Parameters on Selected Properties of Ti6Al4V Manufacturing via L-PBF Process.

This study investigates the microstructural effects of process parameters on Ti6Al4V alloy produced via powder bed fusion (PBF) using laser beam melting (LB/M) technology. The research focuses on how variations in laser power, exposure velocity, and hatching distance influence the final material's porosity, microhardness, and microstructure. To better understand the relationships between process parameters, energy density, and porosity, a simple mathematical model was developed. The microstructure of the alloy was analyzed in the YZ plane using a confocal microscope. The study identified optimal parameters-302.5 W laser power, 990 mm/s exposure velocity, and 0.14 mm hatching distance-yielding the lowest porosity index of 0.005%. The material's average hardness was measured at 434 ± 18 HV0.5. These findings offer valuable insights for optimizing printing parameters to produce high-quality Ti6Al4V components using PBF-LB/M technology, shedding light on the critical relationship between process parameters and the resulting microstructure.

The novel Vogel's approximation method integrated with a random forest algorithm in the vibration analysis of a two-directional functionally graded taper porous beam: Assessment

A functionally graded material is a class of composite materials characterized by gradual variations in composition and microstructure, which further induces the respective changes in the material properties. This study focuses on evaluating the vibration behavior of two directional functionally graded taper porous beams (FGTPB). This approach adopts a rectangular cross-section in order to deal with the challenges related to fluctuating material characteristics and geometric tapering in both thickness and width dimensions. The research employs a novel approach that merges Vogel's approximation technique with the Random Forest algorithm, an approach that has not been used in analyzing structural vibrations, establish boundary conditions and solve equations of motion. Comparative results of the suggested beam theory with the existing literature on FGTPB materials such as alumina and SUS304 at various taper, porosity, gradient and width ratios verified it. The material gradation and porosity developed a uniform pattern in the first three modes of fundamental frequencies. Higher gradient indices increased the rigidity and natural frequencies of the beams whereas the porosity index decreased the rigidity, resulting in lower natural frequencies. By combining Vogel's approximation method with machine learning techniques, the study improved vibration behavior analysis in FGTPB. The disciplines of materials and structural engineering are significantly impacted by this.

Modelling the effective thermal conductivity and porosity of an open-cell material using an image-based technique coupled with machine learning

Effective thermal conductivity is considered one of the most important parameters in the characterization of insulating materials. The effective thermal conductivity of open-cell porous materials is influenced by both their microstructure and the types of solid and fluid phases present. Currently, many analytical models are available for predicting the final performance based on material porosity, as well as the thermal conductivity of the solid and fluid phases. However, these procedures have two main drawbacks: difficulty in selecting the correct prediction model and challenges in accurately determining porosity. Moreover, when attempting to measure effective thermal conductivity, strict procedural conditions and defined sample geometries are required, necessitating multiple samples due to variations in porosity from specimen to specimen. The procedure proposed here aims to address these challenges. Utilizing microtomography coupled with 3D virtualization and finite element method simulation, this procedure provides validated results which are then used as a dataset to train a machine-learning model capable of predicting thermal conductivity across a comprehensive range of porosities, solid thermal conductivities and fluid thermal conductivities. Comparative analysis has demonstrated that this procedure is significantly more accurate than conventional analytical models or measurement procedures and it has the potential to be applied to any material.

A poroelastic [formula omitted]-SPH model for modeling biofilm deformation and sloughing in microfluidic channels

We present a poroelastic fluid–structure interaction δ-SPH model for simulating biofilm deformation and sloughing in microfluidic channels. Based on the mixture theory, this model accurately handles large deformations of solid structures and simultaneously simulates seepage flow within the porous biofilm and external flow. A key advantage of the model is its reliance on the solid phase material properties rather than the averaged properties of the biofilm, enabling the modeling of changes in porosity and biofilm material properties induced by loads. Model verification is achieved through two benchmark problems, followed by application to biofilm deformation and sloughing studies. The Young’s modulus of biofilms is a key parameter of interest in many studies. Calibration of the biofilm’s solid material elasticity modulus by using the presented model yields a value of 200 Pa, aligning with previous reports in literature. Additionally, the model is capable of simulating the sloughing process by evaluating local von Mises equivalent stress, reproducing different detachment patterns corresponding to various material strengths. This δ-SPH model offers an efficient numerical tool for biofilm analysis and is extendable to simulate other fluid–structure interaction problems involving porous media with large deformations, such as soil, debris flow, and biological tissues.

Improved Low-field NMR porosity characterization of cementitious materials containing water-soluble organic admixtures

Water-soluble organic admixtures (WSOAs) are widely used in cementitious materials, and may affect the porosity, but their effects on low-field nuclear magnetic resonance (LF-NMR) measurement are often overlooked. Using viscosity modifying admixture (VMA) as an example, this study demonstrates the presence of WSOAs would lead to an overestimation of porosity and a leftward shift of pore size distribution using LF-NMR. This is attributed to the formation of hydrogen bonds between polymer and water molecules, and the decreased distance between nuclear spins, respectively. A strategy is proposed to improve the accuracy of the porosity characterization by eliminating the additional effects of WSOAs in LF-NMR testing. The results show that the addition of small molecular mass non-ionic VMAs replacing mixing water (within a 20 % replacing rate) does not alter the porosity of the paste. This method can be extended to characterize the porosity of various porous materials containing WSOAs.

High speed enrichment of benzoylurea insecticides by hierarchical pore nitrogen doped carbon materials induced with hydrogen-bonded organic frameworks

The high speed enrichment of benzoylurea insecticides (BUs) in complex matrices is an essential and challenging step. The present study focuses on the synthesis of a hierarchical pore nitrogen-doped carbon material for magnetic solid phase extraction (MSPE) of BUs. This material was prepared through the carbonization of a composite material ZIF-67@MCA which assembly with hydrogen-bonded organic frameworks (melamine-cyanurate, MCA) and zeolitic imidazolate framework (ZIF-67) at room temperature. The optimal adsorption effect is achieved when the mass ratio of ZIF-67 to MCA is 1/3, and the carbonization was performed at 600 °C, the such obtained carbon material was denoted as 1/3ZIF-67@MCA-DCs-600. The material was characterized with various physical methods including X-ray diffractometry (XRD), Fourier transform infrared spectrometry (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), Brunauer–Emmett–Teller (BET), vibrating sample magnetometer (VSM), water contact angle measurement, Raman spectrometry. 1/3ZIF-67@MCA-DCs-600 exhibits a macro-mesoporous 3D structure with a high degree of nitrogen doping and relatively large specific surface area, making it suitable for magnetic solid phase extraction (MSPE). The adsorption of BUs with concentration of 100 ng mL-1 can reach equilibrium within 5 s. The interaction between BUs and the adsorbent, facilitated by π-π stacking, hydrophobic interactions, hydrogen bonding forces, as well as the material's porosity, enables efficient extraction recoveries ranging from 45 % to 92 %. The enrichment of BUs was achieved through the establishment of an MSPE method under optimized conditions, which was further coupled with high performance liquid chromatography (HPLC) for the determination of the four BUs. The linear range spans from 5 ng ml-1 to 1000 ng ml-1 with the correlation coefficient (R2) of ≥ 0.99, Meanwhile, the detection limit for these four BUs falls within the range of 0.01 to 0.10 ng ml-1. The material exhibits good reusability and can be reused for at least 5 cycles. Inter day and intra-day precision ranges from 2.1-7.9 % and 1.0-5.4 %, respectively. The method demonstrates a high level of reliability in practical applications for the determination of BUs.

The role of polymer gel electrolyte infiltration for enhancement of capacitance and cycle stability

With the increasing application of electronic materials in various fields such as flexible electronic textiles, wearable and portable gadgets, aerospace and aircraft systems etc., the demand for clean high-power energy storage devices is also increasing rapidly. To date, the application of market available supercapacitors has not met the energy expectations in the range of market leading Li-ion batteries (LIBs) due to their unreliable mechanical flexibility, electrolyte leakage, low voltage application, low capacity, low cycle stability and moderate rate-capability. Inappropriate utilization of the maximum porosity of the electrode material and inefficient activities of the electrode/electrolyte interface are major challenges for present supercapacitor development. In this work, for the first time, the role of polymer gel electrolyte infiltration to improve the electrochemical performance of a supercapacitor has been explicitly studied and investigated. It has been observed that 1-Ethyl-3- Methylimidazolium bis(trifluoromethylsulfonyl)imide [EMIM][TFSI] ionic liquid electrolyte embedded in Polypropylene Carbonate (PPC) and Polycarbonate (PC) polymer matrix polymer gel electrolyte (PGE) showed excellent supercapacitive performance at high voltage window 2.6 V by delivering maximum total capacitance of 5.81 F and maximum energy density 10.9 Wh kg-1 at 30 mA current (0.06 A g-1). Regular infiltration of the polymer gel electrolyte inside the electrode material is also observed during long cycle operation of 10,000 cycles. Infiltration of electrolyte ions into the pores of electrode materials plays a significant role in increasing capacitance and cycle Stability. These results highlight the potential of this novel high-voltage polymer gel electrolyte for future high-power energy storage device applications.

Feasibility study on conversion of biowaste of lemon peel into carbon electrode for supercapacitor using ZnCl2 as an activating agent

Here, we describe the analysis of the capacitive performance of activated carbon materials derived from the biowaste of lemon. Lemon peel discarded by restaurants after juice extraction is carbonized at 400 0C followed by chemical activation using ZnCl2. The porosity of carbon materials is tailored by varying activation conditions, such as the mass ratio of carbonized lemon peel and ZnCl2, duration of heating, and temperature. The Brunauer–Emmett– Teller (BET) surface area and pore volume of carbon materials prepared at different activating conditions range from 1380 to 2120 m2g−1 and 0.38 to 0.69 cm3 g−1 respectively. The derived carbon materials are amorphous indicated by the broad peaks in the XRD pattern as well as disordered structure of the carbon materials is revealed by the Raman spectroscopic analysis. The systematic analysis of capacitive performance of activated carbons by employing electrochemical techniques like Cyclic Voltammetry (CV), Galvanostatic charge/Discharge (GCD) cycles, and electrochemical impedance spectroscopy (EIS) in acidic (H2SO4) and alkaline (KOH) media indicates that optimum condition for activation of lemon peel is 600 °C for 60 min with 1:1 mass ratio of carbonized lemon peel and ZnCl2. The superior performance of (ALP-600) is attributed to its high surface area and well-connected hierarchical porous structure. The tiny hump at ~ 0.2 V in CV might be due to the pseudocapacitive nature of oxygen functional groups indicated by FTIR. ALP-600 exhibits the highest specific capacitance of 180 Fg−1 and retains 99.7% of its initial capacitance after 5000 cycles in the acidic electrolyte. The maximum capacitance achieved with ALP-600 symmetric cell in CR2032 coin cell configuration is 0.90F.

Dispersion of thermoelastic guided waves in multi-layered porous media

The mechanical properties of the graphite electrode will dynamically change during the charge-discharge cycle, which will affect the propagation characteristics of guided waves in lithium-ion batteries. Meanwhile, lithium-ion batteries experience fluctuations in operating temperature during cycling, which will also influence the propagation of guided waves. This research aims to investigate the guided wave propagation problem of porous electrode material with electrolyte versus temperature. The problem is under the framework of Green-Naghdi theory and Biot theory, and a numerical approach is presented to solve the thermoelastic wave propagation characteristics in such a multi-layered porous electrode. A frequency domain simulation for a multi-layered porous anode will be established. The simulation results confirm the feasibility and accuracy of the proposed approach. The porosity of the anode material shows obvious dynamic variation during cycling, which illustrates a strong correlation with the elastic modulus of the solid skeleton. Then, the effects of porosity and temperature variations on the propagation characteristics of thermoelastic guided waves in multi-layered porous graphite electrodes will be analyzed in detail. The phase velocity of fundamental modes appears regularly shift in the low frequency range. This may provide theoretical support for the acoustic nondestructive characterization of the operating states of the lithium-ion batteries.

Dual-function CoNi-LDH hollow porous spheres for morphology-driven adsorptive removal and photo-oxidative degradation of anionic dyes

The layered double hydroxides (LDHs) emerged as a class of low-cost potential adsorbents for organic pollutant separation, whereas the deep study of organic dye separation regulated by LDH hollow morphology under ambient conditions is still lacking. To address this gap, ZIF-67, Bulk-CoNi-LDH, and HPS-CoNi-LDH materials of different morphology and porosity were synthesized and investigated in the dye separation process. Methyl orange (MO), congo-red (CR), methylene blue (MB), and rhodamine B (Rhb) dyes were selected as model dye pollutants. The spectroscopic and structural analysis reveals the HPS-CoNi-LDH exhibits less-aggregated 2D nanosheets, high BET surface area of 163.2 m2/g, large pore size of 12.29 nm, greater positive surface charges (27.5 mV), superior optical (2.18 eV), and charge-separation capabilities as compared to Bulk-CoNi-LDH, Which provides potential sites for adsorptive and photo-degradation for anionic dyes under natural sunlight. Therefore, it achieves a remarkable removal efficiency of 92.6% for methyl orange (15 ppm) with a superior kinetic rate of 3.0×10−2 min−1 within 90 min, outperforming Bulk-CoNi-LDH and ZIF-67 having removal efficiency of 71.7% and 40.8%, and kinetic rate of 1.35×10−2 and 0.5×10−2 min−1, respectively. Poor removal efficiency and kinetic by ZIF-67 was mainly due to its smaller pore size (1.16 nm) and surface-confined charges (6.13 mV). Additionally, HPS-CoNi-LDH exhibits superb selectivity (at a ppm level) and excellent recyclability under ambient conditions. The mechanism of photo-catalytic reaction is discussed. These results delineate the hollow morphological LDH structure could be a worthy candidate for selective wastewater treatment and useful for sustainable conditions, which points the way to other crucial anionic micropollutant remediation.

Revolutionizing healthcare materials: Innovations in processing, advancements, and challenges for enhanced medical device integration and performance

Cutting-edge materials have transformed the fabrication of medical devices and implants. However, the processing used to create these materials impacts their mechanical, physical, and biological characteristics, preventing effective integration. This study is intended to provide a detailed analysis of healthcare materials processing techniques, stressing healthcare-specific material requirements, such as biocompatibility, mechanical strength, corrosion resistance, stabilizability, and bioactivity, followed by classifying these processing methods as “ordinary” and “edge-cutting” methods. The consequences of each processing on the material, as well as the benefits, drawbacks, and recent developments of each technique, are also aimed to be concluded. The study also aimed to explore how process factors affect product qualities. The articles are collected from the Scopus and Web of Science databases using the search strings “Advance Material,” “Material Processing,” “Healthcare,” and “HealthCare Application.” The assessment of the selected literature has been done in accordance with the objectives. The assessment emphasizes quality assurance and regulatory compliance by stressing the need for quality assurance, characterization, and testing for medical devices and implants. Processes such as polishing, etching, and coatings improve biocompatibility and reduce infection risk, according to the findings. It was also concluded that cutting-edge processing methods such as additive manufacturing (3D printing) and electrospinning provide exact control over material composition, structure, and porosity, making them ideal for many clinical applications.

The Influence of Calendering Process on the Graphite Anode

Calendering, or pressing, is the final property-defining process for battery electrode manufacturing to maximize the volumetric capacity of the cell through the compaction of an electrode between two large calender rollers12. On one hand, it can reduce the porosity of battery materials thus increase the conductivity of the materials. On the other hand, it can control the thickness of the electrodes, making sure it is uniform and proper thickness to guarantee the minimal variation in the cell thickness, reaching even stack pressure for module assembly and impacting the thermal management [3]. The calendering process significantly influence the performance of lithium-ion battery (LIB).Graphite anode coating on Cu foil was chosen as our baseline coating for this calendering process investigation. The slurry was mixed in a planetary and dispersive mixer and then coated using reverse comma coating method by a scale-up coater with drying zones of 70 °C. Then the coating was calendered by a calendering machine at various conditions.Calendering, though seemingly a simply process, is influenced by several different parameters significantly. In this study, we systematically investigated the calendering process by carrying-out a Design-of-experiment (DOE). The following calendering parameters were investigated: the parameters of calendering machine gap size, calendering pressure, and the speed of the coating web. The calendered graphite coating was then measured for the morphology by scanning electron microscopy (SEM), the pore size change by BET surface area measurement, and Direct current internal resistance (DCIR) by building half cells and cycling and Electrochemical Impedance Spectroscopy (EIS) at 50% State-of-Charge (SOC).The result showed that pressure is the most critical parameter for calendering and the internal resistance and ionic conductivity changes in response to the calendering parameters. The half-cell with calendering at the pressure of 37 MPa, gap size targeted for 30% porosity, the BET surface area around 0.75 m2/g showed highest cell capacity and lowest internal resistance.

Metal-organic framework incorporated polybenzimidazole aerogel fibers with dual protections for thermal hazards and chemical warfare agents

Aerogel fibers possess the flexibility of fiber materials and the high porosity and low thermal conductivity of aerogel materials, which hold great promising for applications in thermal insulation and personal protection. However, the inferior mechanical performance and the lack of functionality have impeded the wider applications of these fascinating materials. Herein, we report a novel kind of MOF/polybenzimidazole composite aerogel fibers (CAFs) with both physical and chemical protection functions. The CAFs are fabricated by an oxidation induced sol–gel transition spinning method that utilized the transition of labile imidazole/Co2+ coordination bonds to stable imidazole/Co3+ coordination bonds upon oxidation. The incorporation of MOF has obviously improved the strength and ductility of CAFs due to the good interfacial interactions with matrix and increased crosslinking among polymer chains. The CAFs maintain the high thermal stability and flame retardancy of polybenzimidazole matrix, while the increased porosity and surface area with the addition of MOF have lowered the thermal conductivity and improved the thermal insulation performance of CAFs. The uniform porous skeleton also facilitates the access of chemical warfare agents (CWAs) to MOF inside the fiber. The catalytic experiments show that the CAFs have better degradation effect on CWAs than pure MOF powder, dense composite fiber, and MOF coated fiber. This work is expected to provide an efficient strategy for strong and multifunctional aerogel fibers.

Enhancing the porosity of chitosan sponges with CBD by adding antimicrobial violacein

Given the growing interest in non-toxic materials with good anti-inflammatory and antimicrobial mechanical properties, this work focuses on preparing chitosan sponges with violacein and cannabis oil crosslinked with dialdehyde chitosan. The sponge was tested for its physicochemical and biological properties, presenting a high swelling rate, good thermal stability, and satisfactory mechanical properties. The obtained sponge's water vapor transmission rate was 2101 g/m2/day and is within the recommended values for ideal wound dressings. Notably, adding violacein favorably affected the material's porosity, which is essential for dressing materials. In addition, studies have shown that the designed material interacts with human serum albumin and exhibits good antioxidant and anti-inflammatory properties. The antibacterial properties of the prepared biomaterial were assessed using the Microtox test against A. fisherii (Gram-negative bacterium) and S. aureus (Gram-positive bacterium). The investigated material provides potential therapeutic benefits due to the synergistic action of chitosan, violacein, and cannabis oil so that it could be used as a dressing material. The natural origin of the substances could provide an attractive and sustainable alternative to traditional commercially available dressings.

An experimental investigation on transpiration cooling with phase change subjected to non-uniform flame

Transpiration cooling with phase change is promising for thermal protection of scramjet engine due to the combined advantages of latent heat absorption of coolant and thermal insulation of gas film. Previous investigations primarily focused on the transpiration cooling subjected to uniform incoming flow. However, few investigations have revealed the effect of the non-uniformity of high-temperature flame on transpiration cooling with phase change. Moreover, the effect of porosity on transpiration cooling performance was seldomly mentioned. Herein, we experimentally investigate the transpiration cooling in porous media of alloy (Inconel 600) with deionized water as the coolant subjected to the non-uniform high-temperature flame. Moreover, the effects of porosity and type of transpiration material on cooling are investigated. Results show that when the injection rate is less than 16 %, local overheating occurs on the surface of the porous materials. The overheating phenomenon occurs earlier at lower injection rates. Moreover, the decrease in porosity of the transpiration material will lead to increases of the surface temperature and top/back surface temperature difference, as well as decreases of top-surface temperature non-uniformity and cooling efficiency. In addition, for the different porous materials with similar thermal conductivity, the specific surface area exhibits a dominant factor in transpiration cooling.

Parameters of rocket engine chambers, obtained by selective laser fusion

When designing and testing a low-thrust rocket engine (SLME), one of the most important tasks is to ensure the quality of materials, which, in turn, affects the reliability of the product. Currently, additive technologies for manufacturing parts from metals are actively developing. This direction is relevant for rocket and space technology products to reduce weight and increase the reliability of products. The article presents the results of studies of the chemical composition and mechanical characteristics of the material of the low-thrust rocket engine demonstrator chamber, manufactured by selective laser fusion from metal powder. The properties of products made from Inconel 718 metal powder were studied. Samples were made and the chemical, mechanical and structural characteristics of the material were studied. Based on the test results, two RDMT samples were printed. RDMT chambers were tested for vibration loads, strength and tightness. Increased porosity and roughness of the test material of the engine chamber were noted. When analyzing a number of parameters of the selective laser fusion technology, an experimental selection of printing parameters was carried out and the most significant factors affecting the print quality (surface roughness and porosity) were identified. Based on the results of the work carried out, four groups of controlled printing parameters were identified that affect the properties of the resulting material. The work also provides recommendations on printing modes and characteristics to obtain the highest quality parts.

Controlling the Degree of Interpenetration in Chiral Three-Dimensional Covalent Organic Frameworks via Steric Tuning.

Network interpenetration plays a crucial role in functionalizing porous framework materials. However, controlling the degree of interpenetration in covalent organic frameworks (COFs) to influence their pore sizes, shapes, and functionalities still remains a significant challenge. Here, we demonstrate a steric tuning strategy to control the degree of COF interpenetration and modulate their physicochemical properties. By imine condensations of 1,1'-bi-2-naphthol-derived tetraaldehydes bearing different alkyl substituents with the monomer tetra(p-aminophenyl)-methane, we synthesized and characterized a family of two-component and three-component chiral COFs with different interpenetrated dia networks. The alkyl groups are periodically appended on the pore walls, and their types/contents that can be synthetically tuned control the interpenetration degree of COFs by minimizing repulsive interactions between the alkyl groups. Specifically, the COF with -OH groups adopts an interpenetrated dia-c5 topology, those with -OMe/-OEt groups take an interpenetrated dia-c4 topology, whereas those with the bulky -OnPr/-OnBu groups exhibit a noninterpenetrated dia-c1 topology. The multivariate COFs with both -OH and -OnBu groups display either a noninterpenetrated or dia-c5 topology, depending on the proportion of -OnBu groups. The extent of interpenetration in COFs significantly affects their porosity, thermal stability, and chemical stability, resulting in varying selective performances in the adsorption and separation of dyes and asymmetric catalysis. This work highlights the potential of using steric hindrance to tune and control interpenetration, porosity, stability, and functionalities of COFs materials, broadening the range of their applications.

Mechanics and microstructure analysis of geopolymer utilizing ilmenite tailing and metakaolin powder as alkali-activated materials

Geopolymers derived from bulk solid waste are considered ideal substitutes for cement-based materials in developing environmentally friendly construction materials. The utilization of solid waste tailings powder as a precursor for alkali activation of geopolymer can enhance the mechanical characteristics of geopolymer. This study conducted extensive experimental studies on the compressive strength, flexural strength, SEM microstructure, thermogravimetric curve, and variable influence of alkali-activated ilmenite tailings (IT) geopolymer mortar, using the liquid-solid ratio and the number of tailings as variables. An analysis was conducted on the mortar's mechanical characteristics, microstructure, and machine-learning properties. Furthermore, the impact of different atomic ratios on the structure and characteristics of geopolymer mortars was also examined. The test results revealed that the metakaolin-iron titanium tailings geopolymer, when doped with 10% ilmenite tailings, exhibited a compressive strength of 72.30MPa at 14 days. Similarly, the flexural strength of the geopolymer reached 4.76MPa at 14 days when doped with 30% ilmenite tailings. XRD analysis showed that Magnesiohornblende particles Mg-F-A-S-H and C-A-S-H gel had positive and negative correlations, respectively, with the tailings doping level. TG results indicated that the specimens exhibit enhanced thermal stability following treatment with tailings. SEM analysis revealed that combining ilmenite tailings with metakaolin formed Me-(F)-A-S-H gels. The examination of surface porosity, pore shape, and unreacted material determined that adding ilmenite tailings increased the Si/Al and Fe/Si ratios, enhancing the transformation of the lamellar structure to the three-dimensional disordered gel mesh structure. Additionally, the tailings contributed a significant amount of Ca, elevating the Ca/Na ratio (0.1−0.6) and triggering calcium precipitation within a Ca/Si range of 0.03−0.2. This increase in calcium led to a decrease in the sample's strength as the curing time was extended. Based on prior research and the application of the Gray Wolf optimization algorithm in extreme learning, a clear negative correlation was identified between the liquid-solid ratio and strength. Furthermore, increasing the Si/Al ratio enhanced the geopolymer's strength, while an extended curing time negatively correlated with strength. The impact of tailings mixing was deemed insignificant when the tailings amount did not exceed 20%. Geopolymers may derive significant environmental and industrial benefits from the improvement of their mechanical properties, thermal stability, and optimization using machine learning.

Evaluation of Physical Properties in Carboxymethyl Chitosan Modified Glass Ionomer Cements and the Effect for Dentin Remineralization: SEM/EDX, Compressive Strength, and Ca/P Ratio.

The aim of this article was to evaluate the effects of modifying glass ionomer cement (GIC) with carboxymethyl chitosan (CMC) on surface morphology and remineralization outcomes by examining dentin morphology and calcium ion composition changes. Thirty holes in a cylindrical acrylic mold were filled with three groups of restorative materials: GIC, GIC modified with CMC (GIC-CMC) 5%, and GIC-CMC10%. The surface morphology of each group's materials was observed using scanning electron microscopy (SEM). The compressive strength measurement was performed using a universal testing machine. The dentin remineralization process was performed by applying GIC, GIC-CMC5%, and GIC-CMC10% materials for 14 days on demineralized dentin cavities treated with 17% ethylenediamine tetraacetic acid (EDTA) for 7 days. A morphological evaluation was conducted using SEM. The calcium ion composition and calcium-to-phosphorous (Ca/P) ratio were examined using an energy-dispersive X-ray (EDX). The Kruskal-Wallis and post-hoc Mann-Whitney U tests were performed to compare all four groups of calcium ions (p < 0.05). The modification of GIC with CMC affected the morphological changes in the materials in the form of reduced porosity and increased fractures. A significant difference was found in compressive strength between the GIC-CMC modification materials of GIC-CMC5% and GIC-CMC10% and the GIC control group. The dentin tubule morphology and surface changes were observed after applying GIC, GIC-CMC5%, and GIC-CMC10% materials for 14 days, as evaluated by SEM. The EDX examination showed an increase in calcium ion content and hydroxyapatite formation (Ca/P ratio) after applying the GIC-CMC10% material. The surface porosity of the GIC modification material with the addition of CMC tended to decrease. However, an increase in cracked surfaces that widened, along with the rise in CMC percentage, was found. This modification also reduced the compressive strength of the materials, with the lowest average yield at 10% CMC addition. Therefore, the modification of GIC with CMC affects changes in morphology, calcium ion composition, and Ca/P ratio in demineralized dentin.