Physical Microstructure Research Articles

The Impact of Mechanical Compression on the Postharvest Quality of ‘Shine Muscat’ Grapes during Short-Term Storage

Mechanical stress induced by compression during preharvest and postharvest handling of fresh fruit is a major factor influencing the quality of fresh fruit. The degree of compression primarily governs the extent of quality deterioration. However, research on the damage mechanisms of mechanical compression in table grapes remains scarce. This investigation evaluated the impact of varying compression levels (0%, 20%, 40%, 60%, and 80%) on the postharvest quality attributes of table grapes. Changes in postharvest physical properties (overall appearance and color), structural properties (firmness, springiness, cohesiveness, and chewiness), physiological qualities (total soluble solids, titratable acidity, ascorbic acid, malonaldehyde content, and relative electrical conductivity), and cell microstructure of the berries was determined at 4 °C during 15 d of storage. Mechanical compression contributed to the deterioration of the quality of table grapes during storage, resulting in increased weight loss, decay rate, malonaldehyde content, and relative electrical conductivity; and decreased total soluble solids, titratable acidity, and ascorbic acid content. Furthermore, as compared to the control group, mechanical compression resulted in substantial yellowing and diminished textural qualities of grapes. In particular, compression treatment caused significant deformation of grape cell microstructure. In conclusion, mechanical compression stress significantly affects the physical and physiological properties of postharvest table grapes, as well as the internal cellular organization. As compression levels increase, the quality of table grapes progressively deteriorates, leading to a substantial reduction in storage life and commercial value. This study offers essential information for devising damage prevention strategies in preharvest and postharvest handling of table grapes.

Effect of The Composition of TiO2 Additives on The Physical and Magnetic Properties Crystal Structure and Microstructure of BaFe12O19 Magnetic Ceramics

<p>In this research, the manufacture of barium hexaferrite (BaFe<sub>12</sub>O<sub>19</sub>) magnetic ceramics and the addition of titanium dioxide (TiO<sub>2</sub>) additives with variations of 0%: 0.3%: 0.6% and 0.9% used the powder metallurgical method. The characterization used in this study is the measurement of density, porosity, X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Vibrating Sample Magnetometer (VSM), and Impulse Magnetizer K-Series. Based on the results of density and porosity measurements, the highest values were 4.95 g/cm3 and 5.45%, respectively. XRD results showed the formation of a BaFe<sub>12</sub>O<sub>19</sub> phase with some impurities at 0% (Fe<sub>2</sub>O<sub>3</sub>), 0.3% and 0.9% (Ti<sub>6</sub>O<sub>11</sub>), and 0.6% (Ti<sub>4</sub>O<sub>7</sub>). The SEM results showed that the morphology of TiO<sub>2</sub>-BaFe<sub>12</sub>O<sub>19</sub> was quite homogeneous, and the size and cavity ranged from 0.5 – 1.5 μm and 0.25 – 0.9 μm, respectively. VSM results show Mr, Ms, Hc, and Bhmax values of 1,489 kG, 3,235 kG, 1,758 kOe, and Bhmax of 0,867 MGOe, respectively. The results of the Impulse Magnetizer K-Series show the maximum and lowest magnetic flux values of 272.65 gauss and 218.10 gauss at 0.6% and 0% variation, respectively.</p>

Synergistic Effects of Multiple Environmental Factors on Degradation of Silicone Rubber Seals under Marine Atmosphere.

In this research, the degradation behavior and failure mechanism of silicone rubber seal rings under the synergistic effects of multiple factors in the marine atmosphere are fully investigated. Firstly, four aging factors of air, temperature, compressive stress, and chemical medium were determined by analyzing the service environment profile of silicone rubber seal under a marine atmosphere environment. Secondly, to better simulate the actual service environment of silicone rubber and shorten the test period, an artificially accelerated aging test was designed and carried out in the laboratory. In this paper, temperature is utilized as the accelerating stress. According to the results of the pre-test, the accelerating stress level is finally determined to be 110-150 ∘C. In addition, the compression set applied is consistent with the constant compression permanent deformation value of 28% of the silicone rubber in the actual service process. Finally, through the macroscopic physical properties and microstructure analysis of the samples before and after aging, the corresponding test results are given, and the failure mechanism is analyzed and discussed in detail. Through the above test results and discussion, it can be concluded that the aging process of multi-factor coupling on the lower silicone rubber seal ring is uneven, and its aging process is not a simple superposition of multiple environmental factors. More importantly, the above test data and results are of great significance for evaluating the service life of silicone rubber seals, which can be utilized in the future to improve the reliability and durability of related equipment in the marine environment.

Physio-mechanical assessment and process mapping of AlSi10mg/Cu material for automobile application

In this study, copper (Cu) particles were used as a replacement for ceramic particles in an AlSi10Mg matrix to lessen the brittleness often associated with ceramic particles when used as fillers in aluminum matrix. AlSi10Mg was combined with 0, 2, 4, and 6% Cu, and microwave sintering was performed at 300, 450, and 600 °C. The composites produced were subjected to physical tests (porosity, density, shrinkage, and relative density), tensile tests (yield and ultimate strength, elastic modulus, and elongation), and microstructure test. Cu particles were observed to be dispersed at 2% and 4% sintering temperatures and clustered at 6% sintering temperatures, according to the microstructural images. The incorporation of 2% and 4% Cu decreased porosity, leading to increased yield, ultimate tensile strength, and elastic modulus respectively. It was noted that 6% Cu addition resulted in strength reduction owing to particle clusters. Sintering temperatures between 300 and 450 ℃ were favorable for all property investigated; nevertheless, temperatures above 600 °C were detrimental to property responses. The proposed process map revealed diverse response values for varying input combination parameters; hence, a Cu dosage of 4% at a sintering temperature of ≤ 450 °C is recommended.

Short-term improvement of ductile geopolymer composites exposed to magnesium sulfate: Mechanical properties, sorptivity, and mechanisms

Geopolymers are eco-friendly substitutions for cement whose manufacture causes high carbon emissions and energy consumption. Drying shrinkage and brittleness are common defects for geopolymers, and polyvinyl alcohol (PVA) fibers can be employed to suppress these defects. Thus, ductile geopolymer composites (DGC) are preferred. Magnesium sulfate attack is one of the durability concerns over the geopolymers employed for construction. However, previous studies focused on long-term exposure behaviors, and the knowledge of short-term exposure influences and mechanisms is limited. To clarify the gaps, the current research investigated the physical properties, mechanical properties, sorptivity, phases, and microstructure of DGC incorporating 0–0.6% vol.% PVA fibers, and the DGC was exposed to 5% magnesium sulfate solution for 0, 30, 60, and 90 d. According to the results, the short-term exposure increased DGC's compressive, flexural, and splitting tensile strengths by 5.25%–8.33%, 12.02%–17.17%, and 19.31%–27.93%, respectively, as well as sorptivity by 55.15%–64.48%. Short-term magnesium sulfate exposure improved mechanical properties and sorptivity, contrary to performance deterioration caused by long-term exposure. Mechanisms for the improvement are as follows: (a) sodium-calcium-magnesium sulfo-aluminosilicate (SCMSAS) crystals were formed in micropores, which reduced DGC's porosity. The decreased porosity enhanced mechanical properties and reduced sorptivity; (b) no large amounts of expansive gypsum and ettringite crystals were detected after short-term exposure, and their substantial formations were the causes of long-term exposure deterioration; (c) aluminosilicate polymer structures were improved owing to increased stability and mean chain length, which helped enhance DGC's mechanical properties.

Storage of spinach juice agglomerates: Physical, flow, structural, and thermal properties.

The objective of this study was to investigate how the various storage temperatures affected the physical properties, flow characteristics, microstructure, and glass transition temperature of spinach juice agglomerates. For this purpose, spray-dried spinach juice powders were processed to agglomerates by using a modified fluidized bed dryer (1.6 m/s airflow rate, 60°C drying air temperature, 20 min processing time, and with different binder solutions containing agents as maltodextrin, gum Arabic, and whey powder isolate). The analyses were carried out every month throughout 6 months while the spinach juice agglomerates were stored at temperatures of 4, 20, and 35°C. The results revealed that over the storage time, the moisture content and water activity values of the agglomerates were generally under 11% and 0.6, respectively. The color values generally showed a decreasing trend depending on the storage time. The solubility times of the samples stored at 4°C were longer than those of stored at other storage temperatures. The SJA-GA had the lowest HR and CI values and thus the best flowability properties during all storage times. There was no detectable change in the structures of SJA stored at 20°C according to the storage time. Throughout the storage time, it was discovered that the glass transition temperature of all spinach juice agglomerates was remarkably similar. Overall, the investigation revealed that storage at 35°C for 6 months might be suitable because it delivered the intended outcomes such as greater flowability and cohesiveness, and shorter wettability and solubility times.

Estimating the relationships between initial constituent molar ratios and physical–mechanical properties of RCFP-GBFS based geopolymers

Recycling waste materials for geopolymer synthesis offers a sustainable solution for reducing environmental impact from construction. In this study, the recycled concrete fine powder (RCFP) and granulated blast furnace slag (GBFS) were used to synthesize geopolymers, and the effects on physical performance, compressive strength, and microstructure were investigated. Building upon the existing results, the quantitative relationships between initial constituent molar ratios (Si/Al, Na/Al, and Si/Ca) and macro-properties of the geopolymers were explored and the influence mechanisms were analyzed. The findings demonstrate that the incorporation of GBFS significantly reduced setting time and increased compressive strength. Additionally, the blending of GBFS effectively enhanced the geopolymerization degree and generated more mixed gelling products of C-(A)-S-H, N-A-S-H and (C, N)-A-S-H, resulting in a refined internal structure of the matrix. The results revealed that the relationships between initial constituent molar ratios and macro-properties were not straightforward and involved multiple models. The initial and final setting times showed complex non-linear correlations with initial component molar ratios, while strong linear correlations were observed between initial component molar ratios and both flowability and compressive strength. A non-linear relationship was found between the setting time and fluidity. The outcomes contribute to the understanding of the interplay between composition, property, and structure in geopolymer materials and provide guidance for the composition design of geopolymers.

Thermal-mechanical treatment of blackcurrant pomace for enrichment in yoghurt

Blackcurrant pomace (BP) is currently rarely used in human nutrition, although it contains a high amount of dietary fibre (∼60%). A proper enrichment of foods could provide a good opportunity to improve the recommended daily fibre intake. Yoghurt, as a dispersed system, with high consumer acceptance, is a suitable candidate for pomace enrichment. Due to its strong tendency towards sedimentation, direct enrichment is not possible. The aim of the study was to thermal-mechanically functionalise BP, to enrich cow milk yoghurt to an amount of 5%. Chemical composition, particle size and techno-functional properties of BP and functionalised BP, as well as functional and rheological properties and physical microstructure of the resulting yoghurts, were characterised. Fermentation of enriched yoghurt with functionalised pomace containing a high amount of soluble dietary fibre (SDF) and in consequence exhibiting a high water retention capacity (WRC) and good swelling behaviour led to improved product texture. The study shows that pomace, as a by-product of juice production, is suitable for enriching dispersed systems such as yoghurt without negatively affecting rheological properties. The results confirm that a thermal-mechanical functionalisation of the pomace is necessary to reach this goal.

Influence of Porous Structure of Non-Autoclaved Bio-Based Foamed Concrete on Mechanical Strength

This study examines the impact of the porous structure on the density and mechanical behavior of a new foamed concrete incorporating hemp shives. The specific aim is to gain a better understanding of how the inclusion of hemp shiv, as well as different additions and foaming methods, influence the density and mechanical strength of the concrete. A total of eight batches of foam concrete were produced and tested, made with a protein-based surfactant agent, with cement, ground granulated blast furnace slag, and metakaolin as binders and hemp shiv as natural aggregates. The effect of several parameters is studied, including elaboration method (direct and preformed), amount of pozzolanic additions (0% and 30 of cement weight%), and incorporation of hemp shiv (5 and 15 vol%) on the resulting physical properties, microstructure, porous structure and mechanical behavior of the concrete. Pozzolanic additions improve slightly the uniformity of pore sizes, which increases the mechanical resistance, especially at 28 days. While hemp shiv incorporation results in increased concrete porosity and air bubble radius, it also decreased uniformity, mechanical strength, and lower cohesion with the cement matrix compared to standard concrete. The results contribute to the development of eco-friendly construction materials and promote the utilization of agricultural waste in the construction industry.

Mechanical properties of ultra-fine grained strips under ultrasonic vibration extrusion cutting

Ultrafine grained materials often have superior mechanical properties. In order to complement the advantages of other preparation methods of ultrafine materials, a new process of ultrasonic vibration extrusion cutting was proposed to induce severe plastic deformation of materials to prepare ultrafine grained strips with superior mechanical properties. The mathematical model, finite element simulation and cutting test were combined to validate each other. The mapping relationship and influence law among process parameters, physical field parameters, microstructures and mechanical properties were studied. After ultrasonic vibration extrusion cutting, average grain size of material was refined from tens of microns to ultra-fine grain level. With the decrease of extrusion ratio, thickness of nanocrystalline surface layer, degree of grain refinement, average microhardness and tensile strength of strip increase gradually. When extrusion ratio is 1.2, 1.5, 1.8 and 2.1, thickness of nanocrystalline surface layer is 52.9 μm, 44.1 μm, 26.5 μm and 22.8 μm, respectively. Compared with original matrix, average internal microhardness of strip is increased by about 39.9%, 37.6%, 32.8%, 24.1%, and tensile strength is increased by about 306.9%, 273.7%, 254.1%, 240.9%, respectively.

Preparation, microstructure, stability in magnesium metallurgy environment of SiC composites

The α-SiC/SiO2 and α-SiC/β-SiC composites were prepared by pressureless sintering. The physical properties and microstructure were characterized. Compared to SiO2, the in situ formation of β-SiC was more beneficial to density of α-SiC composites. The stability in magnesium metallurgy environment of different SiC composites was investigated. The SiC composites are corroded by two ways: SiC activated oxidation and grain boundary corrosion by slag. In low oxygen environment, the activated oxidation of SiC forms SiO, resulting in the destruction of SiC surface structure. The CaO and other oxides in the slag are easy to react with SiO2, which continuously corrodes the grain boundaries and eventually leads to the continuous shedding of SiC grains. In particular, the conversion of β-2CaO·SiO2 to γ-2CaO·SiO2 results in volume expansion of about 12%, resulting in grain boundary expansion and structural failure. The α-SiC/β-SiC composites had higher density and better corrosion resistance to magnesium slag.

Physical and mechanical properties and microstructures of submarine soils in the Yellow Sea

AbstractIn recent years, the exploration of seabed has been intensified, but the submarine soils of silt and sand in the Yellow Sea area have not been well investigated so far. In this study, the physical and mechanical properties of silt and sand from the Yellow Sea were measured using a direct shear apparatus and their microstructures were observed using a scanning electron microscope. The test results suggest that the shear strength of silt and sand increases linearly with the increase of normal stress. Based on the direct shear test, the scanning electron microscope was used to observe the section surface of sand. It is observed that the section surface becomes rough, with many “V”‐shaped cracks. Many particles appear on the surface of the silt structure and tend to be disintegrated. The X‐ray diffraction experiment reveals that the sand and silt have different compositions. The shear strength of sand is slightly greater than that of silt under high stress, which is related to the shape of soil particles and the mineral composition. These results can be a reference for further study of other soils in the Yellow Sea; meanwhile, they can serve as soil parameters for the stability and durability analyses of offshore infrastructure construction.

Novel microporous MgO-based high-temperature thermal insulator

This paper addresses the development of a novel microporous MgO-based (MPMB) thermal insulator whose temperature-resistant microporous structure was engineered for the introduction of controlled packing flaws amongst their highly asymmetric and porous particles during compacting by uniaxial pressing. Hard-burnt MgO, dolomite, and TiO2 particles were dry-mixed with expanded aluminum phyllosilicate and fibers before being sprayed with a colloidal silica dispersion. The mixture was uniaxially pressed as 400 × 100 × 20 mm boards and dried at 120 °C. Samples were thermally treated at different temperatures (120-1100 °C) for the evaluation of their physical properties (compression strength, rigidity, permanent dimensional thermal variation, solid density, total porosity, pore diameter distribution, and thermal conductivity), crystalline phases, and microstructure. The microporous microstructure generated during pressing was not significantly affected by thermal treatments up to 1100 °C and the samples’ thermal conductivity, total porosity, and compression strength varied between 0.20 and 0.14 W (m K)−1, 54–56%, and 29-15 MPa in the 200-1000 °C temperature range.

Effects of titanium gypsum on high calcium fly ash system: Physical and microscopic properties, hydration, and Fe transformation

Titanium gypsum (TG) is a solid waste generated in the sulfate method of TiO2 production. The stockpiling of TG causes harmful environmental issues, but TG could be reused for manufacturing green cementitious materials with fly ash (FA) and calcium carbide residue (CCR). However, the effects of TG on the high-calcium FA–CCR system and the transformation rule of Fe compound in TG remain unclear. Therefore, FA–CCR and FA–natural gypsum–CCR were used as the control group. The effects of TG on the physical properties, phase composition, and microstructure of the FA–CCR system were studied. Furthermore, the transformation role of Fe in TG was revealed by calculating the thermodynamic properties and performing X-ray photoelectron spectroscopy. Results demonstrated that the appropriate addition of TG was found to shorten the setting time and increase the compressive strength of the FA–CCR system, whereas the excessive addition will cause a negative effect. The small crystal size of TG has a greater contribution to the physical properties compared with the negative effect of iron impurities. The addition of TG can optimize the pore structure of the FA–CCR composites. TG reduced the hydration rate of C-(A)-S-H gels at an early age but promoted ettringite generation and polymerization of C-(A)-S-H at the late stage. Fe(OH)3 in TG plays an insert-filling role at an early age, but this compound could transform into Fe(OH)63− and form ettringite in the late hydration stage, thereby promoting the growth of ettringite crystals. The relative conversion rate of Fe(OH)3 to Fe(OH)63− at 60 days is 11.8%.

Low-temperature-sintering of Co2Z ferrite materials via Dy3+ ion doping for use in high-frequency applications

According to this study, Co2Z ferrite is suitable for applications in high-frequency antennas. Ba3Co2Fe24-xDyxO41 samples with different values of Dy3+ doping concentration (x) in the range of 0.00–0.25 were prepared in the study by employing solid-state sintering and 2.5 wt% Bi2O3 sintering aids. A systematic analysis of the physical phase structure, microstructure, and magnetic dielectric properties of the samples was also performed. The X-ray diffraction patterns of the samples showed that doping with Dy3+ ions and the addition of the Bi2O3 sintering aid had not changed the physical structure of the sample material, indicating that the material was still a Z-type hexagonal ferrite. In addition, according to the magnetic hysteresis loops of the samples, all six groups of them exhibited typical soft magnetic properties. With an increase in the Dy3+ ion doping concentration, the saturation magnetization intensity and coercivity of the samples initially increased and then decreased. The sample with a Dy3+ ion doping concentration of 0.15 had the most uniform grain distribution, largest density, and smallest porosity among the samples. Additionally, that sample had the maximum values of the real parts of the magnetic permeability (7.89) and permittivity (13.90) while having a low magnetic loss (tanδμ≤0.04) and a low dielectric loss (tanδε≤0.03). Thus, this type of magnetic dielectric materials will have significant potential for use in high-frequency antenna applications.

Physics-informed machine learning with high-throughput design module for evaluating rupture life and guiding design of oxide/oxide ceramic matrix composites

In this paper, a unified physics-informed machine learning (PIML) model is proposed for the accurate prediction of the creep rupture life of oxide/oxide ceramic matrix composites (CMCs) by incorporating prior physical information and microstructure features. The collected dataset undergoes missing value imputation and standardization methods for processing. Key feature parameters that influence rupture life are identified through global sensitivity analysis. Furthermore, a high-throughput design module is developed to explore optimal composition under specific creep conditions, providing design guidelines for new materials in oxide/oxide CMCs. This study demonstrates that the predicted results consistently fall within the ±3 error bands. Improved life expectancy is attained with fiber modulus (220–290 GPa) and matrix modulus (>310 GPa). The transformation from expensive creep testing to low-cost exploration of modulus and proportional limit is achieved, offering theoretical support and analytical methods for the design of CMC components and the development of new materials for high-temperature applications.

Creep Life Assessment Method for Super304H Boiler Tubes Based on HTS-SQUID Gradiometer

This paper presents a novel method for the creep life assessment of Super304H (KA-SUS304J1HTB, ASME code: 2328) boiler tubes based on a discrete-type eddy-current-testing (ECT) HTS-SQUID nondestructive evaluation (NDE) system. Six specimens were subjected to internal pressure creep tests at a stress level of 110 MPa and a temperature of 700°C. The specimens were inspected at various creep test times using our NDE system, which included an ECT probe and a HTS-SQUID gradiometer. By studying the physical characteristics and microstructures of the specimens at different test times, we found that the electrical conductivity and permeability of the specimens varied with an increasing test time. The detected signals may have been generated from creep voids and/or surface microcracks. Based on the NDE inspection results, creep life assessment curves that can be used for assessing the remaining creep life of the Super304H boiler tubes were plotted. The results confirmed the possibility of assessing the remaining creep life using our HTS-SQUID-based system in a nondestructive manner.

Organic farming systems affect carbon stocks but not soil structure and associated physical properties in a long-term farming trial on Chernozem

An asset of organic farming systems with diversified crop rotations, next to a cut in pesticide and mineral fertilizer application, is the built-up of organic carbon stocks in the long-term. In addition, the inclusion of deep-rooting legumes like alfalfa is known to improve soil structure and increase particulate organic matter contents in the subsoil. These views have been challenged recently ascribing limited potential for legume-based crop rotations to increase carbon stocks in Chernozems (Mollisols) due to limited accrual of mineral-associated organic carbon. Likewise, the direct impact of these legumes on soil structure and associated soil properties like water retention and transport has been questioned and linked to indirect effects instead.The objective of this study was to investigate the impact of legume-based crop rotations on carbon stocks and soil structure properties in the Flurweg II long-term farming systems trial (26 years) established on a Chernozem soil in Germany. We compared one conventional (INT) and two organic farming systems, with (O + M) and without (O - M) integrated livestock management. The three farming systems differ in biomass return via plant residues or farmyard manure as well as share and type of legumes in the eight-year crop rotation (INT: pea, O - M: faba bean and pea, O + M: biannual alfalfa). The comparison included yields, carbon stocks, soil physical properties and microstructure properties based on X-ray computed tomography of soil within and beneath the plow horizon. All farming systems underwent conventional plowing. In addition, we compared carbon stocks and microstructure properties with those from the nearby Westerfeld tillage trial with conventional and reduced tillage in a legume-free crop rotation.The carbon stocks in the plowed topsoil of the Flurweg II systems trial increased significantly with organic farming including livestock (INT: 53 ± 2 vs. O + M: 61 ± 2 t ha−1), but not without (O - M: 53 ± 4 t ha−1), likely because of farmyard manure application in the O + M system. This increase in topsoil carbon stocks is only moderate compared to the increase in topsoil carbon stocks in the Westerfeld tillage trial by switching from conventional to reduced tillage (53 vs. 70 t ha−1). The carbon stocks of the whole soil profile (down to 48 cm) in the Flurweg II systems trial tended to increase with organic farming irrespective of livestock integration (INT: 72 ± 5 t ha−1 vs. O ± M: 82–83 ± 7 t ha−1). Particulate organic matter (POM) contents and biopore diameter below the plow layer tended to increase with alfalfa in the crop rotation of the O + M farming system. However, the legacy effect four years after the presence or absence of alfalfa was only in the range of natural, spatial variability. As a result of similar soil microstructure there was also hardly any difference in hydraulic conductivity and no difference in soil mechanical properties between farming systems.This study shows that Chernozems in this region still have the capacity to increase POM contents and carbon stocks with climate-smart, regenerative agricultural management, but also demonstrate that this has limited effects on structural properties.

A comparative study of ethylenediamine tetraacetic acid induced gas-solid and liquid-solid accelerated carbonation for enhancement of steel slag aggregates

Accelerated carbonation is an effective technique to enhance the hydration reactivity and volume stability of steel slag aggregates (SSA). However, due to limitations in CO2 transport and carbonation kinetics, carbonation of SSA is frequently carried out using pure CO2 under high pressures. In this study, carbonation under 10% CO2 concentration and ambient temperature and pressure was employed to treat SSA. To accelerate the carbonation of SSA, ethylenediamine tetraacetic acid (EDTA)-induced gas–solid (dry) and liquid–solid (wet) carbonation processes were proposed. Effect of EDTA on the physical and mechanical properties and microstructure of carbonated SSA; and the performance of resulting concrete with a selected mix design were examined. Dry carbonation of SSA, prior to which EDTA was sprayed on the surface of SSA, resulted in a denser carbonated layer and consequently higher specific gravity compared to uncarbonated SSA. Concrete samples involving carbonated SSA, on which 0.1 mol/L EDTA was sprayed at 50% of water absorption mass of SSA, followed by carbonation curing for 24 hrs, revealed 24% increase in strength and 75% reduction in expansion when compared to those containing uncarbonated SSA. Wet carbonation of SSA, during which CO2 was injected into SSA-EDTA solution, promoted both carbonation and hydration of SSA, especially in 0.2 mol/L EDTA solution, resulting in the consumption of periclase and enabling the formation of brucite. While strength improvement was not obvious in the presence of brucite that weakened the interfacial transition zone (ITZ) of concrete, expansion was further reduced by the reduced periclase in SSA. Comparatively, EDTA-induced dry carbonation was more effective and required only 0.4 kg EDTA per tonne of SSA.

The role of alginate in starch nanocrystals-stabilized Pickering emulsions: From physical stability and microstructure to rheology behavior

Sodium alginate (SA) was used as a co-stabilizer to improve the Pickering emulsions stabilized by starch nanocrystals (SNC). Compared with pure SNC, SNC/SA complexes possess better neutral wettability with the contact angle approaching to 90°, more surface negative charges, and lower oil–water interfacial tension. These properties of particles make as-prepared emulsion higher stability with the lower creaming index and average droplet size. Furthermore, the emulsion exhibited good stability against salt (0–600 mM) and pH (2.0–6.0) at higher SA concentration (1.0 wt%). Confocal laser scanning microscopy (CLSM) images proved that SNC could be effectively adsorbed at the oil–water interface with the aid of SA. Rheological analysis showed that higher content of SA resulted in improved strength and higher viscosity of emulsion system. Results from this work indicating that SA could be a useful co-stabilizer to fulfill the demands of Pickering emulsions stabilized by SNC with stable characteristics.