Microstructural Analysis Research Articles

Removal of proteins and lipids affects structure, in vitro digestion and physicochemical properties of rice flour modified by heat-moisture treatment.

The objective of this experiment was to investigate the role of endogenous proteins and lipids in the structural and physicochemical properties of starch in heat-moisture treatment (HMT) rice flour and to reveal their effect on starch digestibility under heat. The findings indicate that, in the absence of endogenous proteins and lipids acting as a physical barrier, especially proteins, the interaction between rice flour and endogenous proteins and lipids diminished. This reduction led to fewer starch-protein inclusion complexes and starch-lipid complexes, altering the granule aggregation structure of rice flour. It resulted in a decrease in particle size, an increase in agglomeration between starch granules, and more surface cracking on rice granules. Under HMT conditions with a moisture content of 30%, slight gelatinization of the starch granules occurred, contributing to an increased starch hydrolysis rate. In addition, the elevated thermal energy effect of HMT enhanced interactions between starch molecular chains. These resulted in a decrease in crystallinity, short-range ordering, and the content of double-helix structure within starch granules. These structural transformations led to higher pasting temperatures, improved hot and cold paste stability, and a decrease in peak viscosity, breakdown, setback, and enthalpy of pasting of the starch granules. The combined analysis of microstructure, physicochemical properties, and in vitro digestion characteristics has enabled us to further enhance our understanding of the interaction mechanisms between endogenous proteins, lipids, and starches during HMT. © 2024 Society of Chemical Industry.

Enhancing thermal energy storage properties of blend phase change materials using beeswax.

This study aims to use beeswax, a readily available and cost-effective organic material, as a novel phase change material (PCM) within blends of low-density polyethylene (LDPE) and styrene-b-(ethylene-co-butylene)-b-styrene (SEBS). LDPE and SEBS act as support materials to prevent beeswax leakage. The physicochemical properties of new blended phase change materials (B-PCM) were determined using an X-ray diffractometer and an infrared spectrometer, confirming the absence of a chemical reaction within the materials. A scanning electron microscope was used for microstructural analysis, indicating that the interconnection of the structure allowed better thermal conductivity. Thermal gravimetric analysis revealed enhanced thermal stability for the B-PCM when combined with SEBS, especially within its operating temperature range. Analysis of phase change temperature and latent heat with differential scanning calorimetry showed no major difference in the melting point of the various PCM blends created. During the melting/solidification process, the B-PCMs possess excellent performance as characterized by W70/P30 (112.45J.g-1) > W70/P20/S10 (94.28J.g-1) > W70/P10/S20 (96.21J.g-1) of latent heat storage. Additionally, the blends tend to reduce supercooling compared to pure beeswax. During heating and cooling cycles, the B-PCM exhibited minimal leakage and degradation, especially in blends containing SEBS. In comparison to the rapid temperature drop observed during the cooling process of W70/P30, the temperature decline of W70/P30 was slower and longer, as demonstrated by infrared thermography. The addition of LDPE to the PCM reduced melting time, indicating an improvement in the thermal energy storage reaction time to the demand. According to the obtained findings, increasing the SEBS concentration in the composite increased the thermal stability of the resulting PCM blends significantly. Despite the challenges mentioned earlier, SEBS proved to be an effective encapsulating material for beeswax, whereas LDPE served well as a supporting material. Leak tests were performed to find the ideal mass ratio, and weight loss was analyzed after multiple cycles of cooling and heating at 70°C. The morphology, thermal characteristics, and chemical composition of the beeswax/LDPE/SEBS composite were all examined. Beeswax proves to be a highly effective phase change material for storing thermal energy within LDPE/SEBS blends.

Effect of in situ CO2 mixing of cement paste on the leachability of hexavalent chromium (Cr(VI)).

In situ CO2 mixing technology is a potential technology for permanently sequestering CO2 during concrete manufacturing processes. Although it has been approved as a promising carbon capture and utilisation (CCU) method, its effect on the leachability of heavy metals from cementitious compounds has not yet been studied. This study focuses on the effect of in situ CO2 mixing of cement paste on the leaching of hexavalent chromium (Cr(VI)). The tank leaching test of the CO2 mixing cement specimen resulted in a Cr(VI) cumulative leaching of 0.614mg/m2 in 28 d, which is ten times lower than that of the control mixing specimens. The results in thermogravimetric analysis indicated that a relatively significant amount of CrO42- is immobilised as CaCrO4 during the CO2-mixing, and a higher Cr-O extension is observed in the Fourier transform infrared spectra. Furthermore, a portion of the monocarboaluminate is inferred from microstructural analyses to incorporate CrO42- ions. These results demonstrate that in situ CO2 mixing is beneficial not only in reducing CO2 emissions, but also in controlling the leaching of toxic substances.

Mn-inlaid antiphase boundaries in perovskite structure

Improvements in the polarization of environmentally-friendly perovskite ferroelectrics have proved to be a challenging task in order to replace the toxic Pb-based counterparts. In contrast to common methods by complex chemical composition designs, we have formed Mn-inlaid antiphase boundaries in Mn-doped (K,Na)NbO3 thin films using pulsed laser deposition method. Here, we observed that mono- or bi-atomic layer of Mn has been identified to inlay along the antiphase boundaries to balance the charges originated from the deficiency of alkali ions and to induce the strain in the KNN films. Thus, rectangular saturated polarization-electric field hysteresis loops have been achieved, with a significantly improved twice remanent polarization of 114 μC/cm2 with an applied electric field of 606 kV/cm, which can be comparable to that of the typical Pb-based thin films. Moreover, we directly see the Mn occupation at the A-site of KNN perovskite structure using atomic-scale microstructure and composition analysis. The Mn-inlaid antiphase boundary can further enrich the understanding of perovskite crystal structure and give more possibilities for the design and optimization of perovskite materials.

Preparation of high purity phase (Bi, Pb)-2223 superconducting films by sol–gel method

In this work, a (Bi, Pb)2Sr2Ca2Cu3O10+δ ((Bi, Pb)-2223) solution with good film-forming capability and chemical stability was synthesized through using metal acetates as raw materials, acrylic acid as an additive, and anhydrous methanol as a solvent to adjust the sol formula. Subsequently, (Bi, Pb)-2223 thin films were fabricated on LaAlO3 (LAO) single-crystal substrates via dip-coating technology at different heat treatment temperatures, and the structures and properties of (Bi, Pb)-2223 films were characterized. It was found that when the sol stoichiometric ratio of Bi: Pb: Sr: Ca: Cu was controlled at 1.9: 0.35: 2: 2: 3 and the gel film was heat-treated at 860 °C and dwelled for 120 min in an mixed atmosphere of N2: O2 = 96: 4, the prepared thin film with a pure (Bi, Pb)-2223 superconducting phase exhibited excellent biaxial texture, a dense surface structure, and had a T c of 106 K and a ΔT c of 6 K. The microstructure analysis revealed a layered epitaxial growth of the film along the LAO substrate with a regular arrangement of atoms and a consistent interlayer spacing.

A comparative study on mechanical properties between linear and zigzag pattern holes reinforced with tialite particles during FSW of AA6082 alloy

In this study, a comparison between linear and zigzag patterned holes is carried out where the holes in the pattern are incorporated with tialite/aluminium titanate (Al2TiO5) particles at the weldment region during friction stir welding of AA6082-T6 aluminium alloy. Different values of tool rotational speed (TRS: 1000, 1200 and 1400 rpm) and welding speed (WS: 35, 40 and 45 mm/min) are considered for the fabrication of joints by both patterns. Visually, no defects are found in all the welded samples. Microstructural analysis has proven that the uniform distribution of particles along the weld region can be obtained by using a zigzag pattern. Maximum hardness is found in the stir zone (SZ), whereas minimum hardness is found in the heat-affected zone (HAZ) for all the samples. The maximum ultimate tensile strength (UTS: 268 MPa), maximum yield strength (YS: 200 MPa) and relatively higher elongation (EL: 7.89%) are exhibited by the Z5 sample, whereas minimum UTS (206 MPa) and minimum YS (142 MPa) was exhibited by L3 and Z7 samples, respectively.

Erosion performance of direct-aged Al2O3-reinforced plasma-sprayed composite coatings at high-temperature conditions

The present investigation evaluates the influence of furnace heat-treatment (HT) on the microstructure, microhardness, fracture toughness and erosion resistance of three plasma sprayed composite coatings: a Inconel625–30 wt% micron-sized Al2O3 (In625-MHT) coating, a Inconel625–30 wt% nano-sized Al2O3 (In625-NHT) coating and a Inconel625–15 wt% micron-sized Al2O3 + 15 wt% nano-sized Al2O3 (In625-BHT/bimodal) coating. High temperature solid particle erosion tests were conducted at 900 °C temperature and with at two different impingement angles (90 and 30) in simulated environment using standard erosion-test rig. Coatings were subjected to detailed mechanical and microstructural analysis in order to better understand their erosion mechanism and structure–property correlation. By healing pores and cracks, the furnace HT increases the coatings’ erosion resistance in the order of In625-BHT, In625-NHT, and In625-MHTcoating. In addition, the mechanical properties of In625-BHT coating like porosity (1.0 ± 0.09%), micro-hardness (1299 ± 25Hv) and fracture toughness (5.9 MPa√m) are significantly improved after HT. The presence of grooves and lips on the surfaces of uncoated substrates provides clear evidence that the erosion mechanism involves the combined processes of micro-ploughing and micro-cutting indicating ductile erosion mode. However unimodal and bimodal composite coatings demonstrated a brittle erosion mode.

Functional description of fiber orientation in paperboard based on orientation tensors resulting from μ-CT scans

AbstractModern $$\upmu$$ μ -CT scans offer non-destructive three-dimensional microstructure analysis of various materials. Despite small density contrasts, this technology also accurately captures the complex network structure of paper and paperboard. It provides detailed insight into the fiber orientation distribution in paper, which was previously unattainable with existing measurement methods. The image analysis results are applicable for numerical fiber network models, and simulations based on these models can significantly improve our understanding of the microstructural influence on macrostructural paper properties, such as strength, stiffness, and curl tendency. This work presents a new method for investigating the microstructural fiber orientation in paperboard. Orientation tensors obtained from $$\upmu$$ μ -CT scan image processing are extracted and evaluated. Based on the direction of the orientation tensor’s first eigenvector, the fiber orientation distribution is determined and then approximated by periodic and non-periodic probability density functions (PDFs). In this study, 40 commercial paperboard samples, each consisting of three plies, were analyzed. From a given set of commonly used PDFs, the best fitting ones have been identified based on their original location in the paper roll and on their ply. It was found that the von Mises PDF provided the most accurate representation of fiber orientation distribution in the middle ply, while the Elliptical PDF was the most suitable for the outer plies. Moreover, a more pronounced fiber orientation anisotropy was observed at the edges of the paper roll than in its center. The best PDFs and their function parameters are provided to allow for direct usage in numerical microstructure models of paperboard, thus enhancing their representativeness.

Preparation and property study of sawdust-modified cement mortar

Sawdust, a solid waste generated during stone processing, poses a serious threat to the environment with its untreated accumulation. This paper first analyzes the chemical composition and physical properties of sawdust, and discusses its mechanism of action in cement mortar. By systematically optimizing the blending ratio and modification method of sawdust, the sawdust-modified cement mortar with excellent performance was prepared. This study evaluates the key performance indicators of sawdust-modified cement mortar, such as compressive strength, flexural strength, and durability, through a series of experiments. The experimental results indicate that the incorporation of an appropriate amount of sawdust significantly enhances the mechanical properties of cement mortar, while also improving its durability, particularly in terms of freeze-thaw resistance. Microstructural analysis reveals the mechanism by which sawdust improves the pore structure of cement mortar; the active components in the sawdust react with the hydration products of cement, resulting in the formation of crystalline structures with higher strength.Therefore, the use of sawdust as a modifier in cement mortar can improve its mechanical properties and durability, while simultaneously reducing the accumulation of solid waste and promoting the sustainable development of building materials.

Preparation and properties of alkali-activated fly ash-waste brick porous building materials

This study explores the development of sustainable porous building materials through the alkali-activation of fly ash and waste clay brick powder. Utilizing Class F fly ash and brick powder from demolished buildings, a series of alkali-activated mortars with varying brick powder replacements (0 % to 50 % by mass) were formulated and analyzed. The results reveal that a 10 % brick powder replacement optimizes the compressive strength, reaching 73 MPa at 28 days, attributed to enhanced nucleation and calcium-rich gel formation. However, higher brick content reduces strength due to the dilution of key reactive materials, with a 50 % replacement leading to a strength of 27 MPa. Porosity increases proportionally with brick content, achieving a maximum of 42 % at 50 % replacement, suggesting potential applications in insulation-centric scenarios. Microstructural analysis confirms the formation of a porous network and identifies the phase compositions and reaction products. This research demonstrates the potential of repurposing construction waste into efficient and environmentally friendly building materials, contributing to waste reduction and offering a greener alternative to traditional practices.

TFE Terpolymers: Once Promising - Are There Still Perspectives in the 21st Century: Synthesis, Characterization, and Properties-Part I.

Polytetrafluoroethylene (PTFE) exhibits outstanding properties such as high-temperature stability, low surface tension, and chemical resistance against most solvents, strong acids, and bases. However, these traits make it challenging to subject PTFE to standard polymer processing procedures, such as thermoforming and hot incremental forming. While polymer processing at temperatures above the melting point of PTFE is already demanding, the typically large molar mass of PTFE results in extremely high melt viscosities, complicating the processing of PTFE. Also, PTFE tends to decompose at temperatures close to its melting point. Therefore, fluoropolymers obtained by copolymerizing tetrafluoroethylene (TFE) with various co-monomers are studied as alternatives to PTFE (e.g., fluorinated ethylene-propylene (FEP)), combining its advantages with better processability. TFE terpolymers have emerged as desirable PTFE alternatives. This review provides an overview of the synthesis with various comonomers and microstructural analysis of PTFE terpolymers and the relationships between the microstructures of TFE terpolymers and their properties.

Can Geopolymer Be a Replacement for Portland Cement in Full-Depth Reclamation Projects? Short- and Long-Term Performance Analysis

The fundamental concern of the full-depth reclamation (FDR) technique using Portland cement (FDR-PC) lies in its detrimental effect on the environment. Therefore, researchers are exploring alternative binders that are comparatively greener but compatible with FDR. This study evaluates both the strength and durability aspects of FDR incorporating geopolymer binder (FDR-GP) as an alternative to conventional FDR-PC. Various blends of fly ash (FA) and ground granulated blast furnace slag (GGBS) have been experimented with as geopolymer pre-cursors, ensuring that the additive content does not exceed 20% by weight of the total mix. Sodium hydroxide (NaOH) was utilized for the alkalinization in varying molarities to enhance the performance of the mixes. The experimental design was formulated to achieve a target 7-day unconfined compressive strength (UCS) strength of 4.95 MPa. This was obtained at a lower molarity (M) of 2 M and a 70% FA, 30% GGBS binder content. The mixes performed satisfactorily in both compression and flexure, along with excellent durability properties analyzed through wetting and drying tests. Furthermore, the long-term performance of FDR-GP mixes was investigated with regard to both UCS and flexural strength after 56, 161, and 238 days of curing. Thereafter, a comprehensive microstructural analysis was conducted to understand the fundamental changes in the matrix that influence mix performance. The outcome of this research confirms the potential of using FA/GGBS-based geopolymer as an alternative binder in FDR projects of flexible pavement, the mechanical and durability properties of which adequately satisfy the requirements as stipulated in various design standards.

Corrosion Resistance of Coatings Based on Chromium and Aluminum of Titanium Alloy Ti-6Al-4V

Improvement of wear, corrosion, and heat-resistant properties of coatings to expand the operational capabilities of metals and alloys is an urgent problem for modern enterprises. Diffusion titanium, chromium, and aluminum-based coatings are widely used to solve this challenge. The article aims to obtain the corrosion-electrochemical properties and increase the microhardness of the obtained coatings compared with the initial Ti-6Al-4V alloy. For this purpose, corrosion resistance, massometric tests, and microstructural analysis were applied, considering various aggressive environments (acids, sodium carbonate, and hydrogen peroxide) at different concentrations, treatment temperatures, and saturation times. As a result, corrosion rates, polarization curves, and X-ray microstructures of the uncoated and coated Ti-6Al-4V titanium alloy samples were obtained. Histograms of corrosion inhibition ratio for the chromium–aluminum coatings in various environments were discussed. Overall, the microhardness of the obtained coatings was increased 2.3 times compared with the initial Ti-6Al-4V alloy. The corrosion-resistant chromaluminizing alloy in aqueous solutions of organic acids and hydrogen peroxide was recommended for practical application in conditions of exposure to titanium products.

Three-dimensional structural analyses of the oxygen electrodes in solid oxide electrolysis cells

Solid oxide electrolysis cells (SOECs) have garnered interest as efficient devices for production of clean fuel such as hydrogen gas. However, the industrialization of SOEC technology has encountered significant challenges, such as unsatisfactory performance and insufficient durability. In this study, we aimed to improve the electrochemical performance and stability of the SOEC air electrode by modifying it at various annealing temperatures (900, 1000, and 1100 °C). Electrochemical testing revealed that the SOEC cell with the electrode annealed at 1000 °C for 1 h exhibited the highest current density of 0.88 A/cm2 at 750 °C and 1.3 V, which is 1.76-times higher than that of the cell with the unoptimized electrode annealed at 900 °C. Three-dimensional microstructural analyses using Focused Ion Beam-Scanning Electron Microscope (FIB-SEM) confirmed that the optimized cell is the most porous with sufficient pore surface area, thereby facilitating electrochemical reactions and gas transport, and preventing delamination of the air electrode resulting from lower oxygen partial pressure difference between the barrier layer and air/electrode interface. Side reactions at the interface, including the generation of resistant SrZrO3, are concurrently avoided. These findings demonstrate the potential of the modified SOEC air electrode for improving electrochemical performance and stability.

Comparative microstructural analysis of V2O5 nanoparticles via x-ray diffraction (XRD) technique

Vanadium pentoxide (V2O5) nanoparticles exhibit diverse properties and have been studied for a wide range of applications, including energy storage, catalysis, environmental remediation, and material enhancement. In this work, we have reported the synthesis of vanadium pentaoxide (V2O5) nanoparticles using hydrothermal method. Ammonium metavanadate (NH4VO3) was used as a source of vanadium. These syntheses were carried out at four different concentrations of vanadium source. The hydrothermal reaction was conducted at a temperature of 180 °C for a duration of 24 hours, followed by an additional 24 hours period of natural cooling. Four samples were annealed in air using a muffle furnace at 500 °C for five hours. The x-ray diffraction technique was used to study the structural aspects. A comparative analysis of the microstructure was conducted utilizing the Scherrer method, the Williamson–Hall method and its various models, size-strain analysis, and the Halder–Wagner method. The crystallite size and microstrain were determined using these distinct methods, revealing a systematic correlation between the crystallite size and microstrain obtained through the different techniques.

Modulation of pea protein isolate hydrogels by adding kappa‐carrageenan: gelling properties and formation mechanism

SummaryOur study focuses on the gelling properties of pea protein (PP), which are comparatively weaker than those of other plant proteins, thereby limiting its application. However, we found that the addition of κ‐carrageenan (κ‐CAR) significantly (P < 0.05) increased PP gels' hardness and water‐holding capacity irrespective of gel formation temperature (80 or 95 °C). Rheological and microstructural analysis confirmed a synergistic effect between PP and κ‐CAR, with higher synergy values observed in hydrogels formulated at 95 °C. Molecular force studies revealed that non‐covalent interactions were dominant, with disulphide bonds contributing only to the structure of gels formed at 95 °C. These promising findings not only enhance our understanding of the PP and κ‐CAR gel formation mechanism but also hold practical implications, potentially leading to improved gelling properties of PP and expanding its applications in the food industry.

Utilizing Marble Wastewater in Cement Pastes and Mortars for Enhanced Physico-Mechanical and Microstructural Properties

This research explored the potential of marble wastewater (MWW) in cement paste and mortar production, addressing water scarcity, sustainable growth, and resource management. It investigated the physico-mechanical properties and microstructure of cement materials incorporated with varying amounts of MWW. In this study, we utilized tap water and MWW for mortar quality testing, focusing on parameters including setting times, water absorption, and mechanical strength. The viability of MWW in concrete formulations was confirmed by its acceptable total dissolved solids and alkalinity levels. A comprehensive experimental program determined that using marble wastewater in place of tap water reduced the quantity of water required for cement consistency and generated slightly higher compressive strengths (2, 3, 4, and 6%) after 28 days of curing. Analytical techniques, including Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray analysis, and X-ray diffraction (XRD), were employed for molecular and microstructural analyses, which revealed that MWW had a significant influence on portlandite development and CSH formation at higher replacement levels. In short, this research highlights the feasibility of using MWW in cement products, contributing to sustainable water resources, and industrial waste management and utilization.

A Comparative Study of Artificial Neural Network and Regression Model for Hybrid Additive Manufacturing of Ti6Al4V Parts and Microstructural Analysis

A Comparative Study of Artificial Neural Network and Regression Model for Hybrid Additive Manufacturing of Ti6Al4V Parts and Microstructural Analysis

Bottom Contact Engineering for Ambient Fabrication of >25% Durable Perovskite Solar Cells.

The bottom contact in perovskite solar cells (PSCs) is easy to cause deep trap states and severe instability issues, especially under maximum power point tracking (MPPT). In this study, sodium gluconate (SG) is employed to disperse tin oxide (SnO2) nanoparticles (NPs) and regulate the interface contact at the buried interface. The SG-SnO2 electron transfer layer (ETL) enabled the deposition of pinhole-free perovskite films in ambient air and improved interface contact by bridging effect. SG-SnO2 PSCs achieved an impressive power conversion efficiency (PCE) of 25.34% (certified as 25.17%) with a high open-circuit voltage (VOC) exceeding 1.19V. The VOC loss is less than 0.34V relative to the 1.53eV bandgap, and the fill factor (FF) loss is only 2.02% due to the improved contact. The SG-SnO2 PSCs retained around 90% of their initial PCEs after 1000h operation (T90 = 1000h), higher than T80 = 1000h for the control SnO2 PSC. Microstructure analysis revealed that light-induced degradation primarily occurred at the buried holes and grain boundaries and highlighted the importance of bottom-contact engineering.

Study of temperature-dependent copper iodide thin film by thermal evaporation system

The development of heterostructure devices has gained significant attention towards scientific communities in the present time. This article reports on the effective use of the horizontal thermal evaporation (TE) method to successfully fabricate copper iodide (CuI) films on silicon (Si) substrates. By using the TE technique, CuI-based heterojunctions have been fabricated in this research . CuI exhibits semiconductor qualities of the p-type, making it a promising option for optoelectronic devices in the future. The temperature was varied from room temperature (RT) to 230 °C to synthesise the CuI/Si heterojunction. The structural, morphological, optical, and electrical analyses have been carried out with various substrate temperatures. The x-ray diffraction (XRD) data shows that the CuI films have demonstrated a polycrystalline character and have lattice parameters of 6.03 Å. The Raman spectroscopy study shows the microstructural analysis of CuI films. The field emission scanning electron microscopy (FESEM) study reveals the variation of grain size and shape with synthesis temperature. The atomic force microscope (AFM) was used to estimate the surface roughness. The CuI films were found to be p-type by the Hall effect measurement. The sample synthesised at 130 °C shows the highest mobility of 83.12 cm2 V−1 s−1 with a carrier concentration of 1019 cm−3. The UV-visible (UV–vis) spectroscopy measurements show good absorption of UV light by the CuI thin films. The CuI/Si heterojunctions are rectifying, as demonstrated by the I-V measurements, and those respond well to UV light irradiation.