Changes In Chemical Composition Research Articles

Widely targeted metabolomics analysis of nutrient changes in a new black rice variety ‘Huamoxiang No.3’ (Oryza sativa L. var. Glutinosa Matsum) under different cooking modes

AbstractBackgroundBlack rice is rich in various nutrients, such as anthocyanins, which may undergo some changes during cooking. However, previous studies have been mainly focused on a single substance and paid less attention to the changes in overall nutrient components. Here, we performed widely targeted metabolomics analysis on the chemical compositional changes in a new black rice variety (‘Huamoxiang No.3’) under three cooking modes, including bottom heating (BH), induction heating (IH), and IH + pressure.ResultsAmong the detected 1458 metabolites, 276 and 108 metabolites were differential metabolites after cooking and in three cooking modes, respectively. Cooking increased the contents of most peptides, phenolic acids, and organic acid compounds but significantly decreased those of lipids and flavonoids, particularly anthocyanins. However, phenolic acids such as chlorogenic acid, erucic acid, and p‐coumaric acid increased significantly, possibly due to the release of bound phenols and degradation of flavonoids to phenolic acids, such as thermal degradation of C3G to protocatechuic acid and among the three heating modes, the IH + pressure mode resulted in the most significant changes.ConclusionAlthough cooking reduced the content of flavonoids and anthocyanins, the increase in phenolic acids and other substances contributed to the healthy effect of cooked black rice, and the content of these active substances increased more significantly in the IH + pressure mode.

Influence of High-Temperature Deformation on the Dissolution of δ-Ferrite in Stainless Steels

The dissolution behavior of δ-ferrite in two commercial stainless steels, 15-5PH and M-154, was studied. In this work, a new approach combining hot deformation and additional post-treatment was investigated and compared with conventional annealing heat treatments for the dissolution of δ-ferrite. The results showed the acceleration in the dissolution of δ-ferrite using the new methodology. Samples from each steel were subjected to conventional annealing heat treatments at 1000 °C and 1150 °C, with soaking times of 1, 2, and 3 h. A second set of samples was subjected to hot compression experiments at 900 °C, under different strain rates, followed by post-processing heat treatments at 1000 °C and 1150 °C, while keeping the holding time constant for 10 min. Advanced microstructural characterization techniques such as Scanning Electron Microscopy (SEM), and Electron Probe Micro-Analysis (EPMA) were employed to investigate δ-ferrite dissolution in terms of changes in area fraction and chemical composition. The results indicated a strong correlation between the dissolution behavior of δ-ferrite and the processing parameters. In addition, thermodynamic calculations using Thermo-Calc software (version 2021.2.87071-368) were used to assess the diffusion of elements during the dissolution of δ-ferrite as a function of temperature and time.

Effects of Silicone Rubber on Rheological Properties and Aging Characteristics of Asphalt Binder

Silicone rubber (SR) is a kind of polymer insulation material with excellent performance. With the service life of silicone rubber products reaching the limit, how to dispose of waste silicone rubber is an urgent problem to be solved. In this paper, silicone rubber-modified asphalt binder (SRMA) was prepared by SR and 90# base asphalt binder. The simulated short-term aging and long-term aging tests of SRMA were carried out using the thin film oven aging test (TFOT) and pressure aging vessel test (PAV). The rotary viscosity test and dynamic shear rheological test (DSR) were applied to the rheological properties of SRMA before and after aging. The degradation degree and chemical composition changes of SR were explored by the toluene insoluble matter test, Fourier transform infrared spectroscopy (FTIR), and a Fluorescence microscope (FM). The results demonstrate that SR can significantly affect the aging resistance, fatigue life, and high-temperature stability of SRMA. As the content of SR rose, the elastic component in SRMA increased, leading to a nice performance in stability at high temperatures and fatigue resistance. However, excessive content (14%wt and 16%wt) had a negative influence on the performance of SRMA. So, the optimal content was speculated to be between 12% and 14%. Furthermore, SR and asphalt binder would be aged and degraded together in the aging process, and this phenomenon was more obvious during long-term aging.

Effect of Heat Treatment on the Supramolecular Structure of Copolymers Based on Poly(propylene glycol fumarate phthalate) with Acrylic Acid

Previous studies investigating the thermal decomposition of p-PGFPh:AA copolymers in an inert atmosphere have provided only a general understanding of the changes that occur during thermolysis. Comprehensive studies are required to gain a better understanding of these processes [1]. The most comprehensive information on the influence of various factors on both the kinetics and the supramolecular structure of the resulting products can be obtained by combining the method of thermal analysis with IR, mass spectrometry, and scanning electron microscopy. The compounds studied have two different compositions, namely p‑PGFPh:AA 6.77:93.23 mol % and p-PGFPh:AA 86.67:13.33 mol %. These compounds were then subjected to a thermolysis process, which resulted in the emission of gases and a decrease in sample weight. The degradation process can be divided into three stages: 1) Depolymerization of the main chain; 2) Depolymerization of the side chain; 3) Final decomposition. These processes occur sequentially at different temperature ranges. According to TG- and DTG studies, complete decomposition of p-PGFPh:AA copolymers occurred at Tterm = 340–350 °C. In this temperature range, a slight loss of sample mass (less than 10 wt %) was observed along with a slight gas evolution. The main gaseous products from the transformation of the studied samples were CO and CO2. This was supported by IR-CO (2000–2200 cm−1) and CO2 (2310–2370 cm−1) as well as mass spectrometric observations. The final products resulting from the thermolysis of p-PGFPh:AA copolymers were examined under an electron microscope. The results showed a similar morphological pattern of mesostructures with sizes ranging from 0.3–1.5 μm, which were observed depending on the porous structure of the initial polymer material. Based on the experimental data, it can be concluded that the p-PGFPh:AA copolymers (in proportions of 6.77:93.23 mol % and 86.67:13.33 mol %) have a relatively high degree of resistance to heating and do not undergo any changes in chemical composition, particle size and shape. In conclusion, the results clearly indicate that the selection of conditions for pyrolysis plays a crucial role in increasing the thermal stability of polymeric materials. This method allows for purposeful changes in the structure and properties of polymers.

Preparation and weathering properties of Ce/TiO2 anti-UV coating on heat-treated wood

Heat-treated wood is widely used as building exterior wall panels and landscape materials due to its excellent dimensional stability and durability. However, heat-treated wood is susceptible to discoloration and cracking due to ultraviolet radiation, temperature and humidity changes in the outdoor environment. In this study, Ce/TiO2 alcohol solution was prepared by sol-gel method, and the inorganic anti-ultraviolet coating was attached to the surface of wood by brush coating. Then artificial accelerated weathering test was carried out for 672 h to evaluate the weathering behavior of heat-treated wood. UV–Vis spectroscopy and macroscopic morphology analysis of the glass substrate show that the coating has good transparency and effective UV shielding ability. Scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analysis showed that the coating successfully adhered to the wood surface and played a good anti-ultraviolet effect. After artificial weathering, the color difference values of unmodified wood, Ce modified wood, TiO2 modified wood and Ce/TiO2 modified wood were 6.04, 4.97, 3.67 and 3.29, respectively. Based on the changes of color and wood chemical composition, the Ce/TiO2 anti-ultraviolet coating can significantly improve the weathering resistance of heat-treated wood, and ultimately limit the degradation degree of surface chemical composition of heat-treated wood.

Soaking Salt Solution Increases Moisture Content, Ash Content, Starch Content, Decreases Solubility and Swelling Power Of Banggai Yam Flour

Purpose: This study aims to investigate the effect of salt solution (NaCl) soaking on yam, focusing on food safety, organoleptic quality, and changes in chemical composition during the soaking process. Methodology: The method used was a factorial Complete Random Design with the following treatments: P0 = no treatment; P1 = soaking in 10 g/liter salt solution; P2 = soaking in 30 g/liter salt solution; P3 = soaking in 50 g/liter salt solution. Each treatment was repeated three times, resulting in 12 observation units. Results: The results indicated that higher salt solution concentrations led to increased water, ash, and starch content, while the solubility and swelling power of yam flour decreased. Findings: The study found that salt soaking positively affects the preservation and quality of yam by inhibiting pathogenic microorganisms and slowing down tuber rot. The increased concentration of salt solution was directly proportional to the increase in water, ash, and starch content. Novelty: This research provides new insights into the effects of salt soaking on yam, particularly on its chemical composition and potential benefits for food preservation. Originality: The study offers a detailed analysis of how different concentrations of salt solutions affect the quality and chemical properties of yam, contributing to the understanding of its implications for food safety and health. Conclusions: Soaking yams in higher concentrations of salt solution enhances their preservation by increasing water, ash, and starch content, while reducing solubility and swelling power. Paper Type: Empirical Research Paper Keywords: Flour; Salt; Soaking; Yam Banggai

Study on water tree resistance and self‐healing properties of multi‐monomer melt‐grafted polyethylene

AbstractIn order to suppress the damage of cable insulation caused by water tree structure formed by micro‐droplets at insulation defects in low density polyethylene (LDPE) materials under AC electric field. In this paper, the siloxane group is grafted onto LDPE by melt grafting method, and different content of comonomer styrene (St) is added to improve the grafting rate of siloxane group grafted polyethylene. The effect of St on the microscopic characteristics of LDPE grafted KH570 is studied. In order to verify the accuracy and timeliness of water tree self‐healing of grafted polymer insulation materials, the microstructure characteristics of LDPE ungrafted and grafted polymer samples are analyzed by Fourier transform infrared spectroscopy, gel content test, and differential scanning calorimeter. Second, the AC dielectric properties of LDPE ungrafted and grafted polymer samples are studied by AC breakdown experiment and space charge test. Finally, the water tree length, micropore defects, and self‐healing of the samples are observed by optical microscopy and polarization and depolarization current method, and the changes of chemical composition in the water tree area before and after aging are analyzed by infrared spectroscopy. The principle and mechanism of repairing water tree defects with grafted monomers are explained. This paper not only combines the previous research results of self‐healing materials, but also provides a new method for the preparation process of LDPE grafted polymer, which has a good research prospect in practical application.

Mapping of lithium ion concentrations in 3D structures through development of in situ correlative imaging of X-ray Compton scattering-computed tomography.

Understanding the correlation between chemical and microstructural properties is critical for unraveling the fundamental relationship between materials chemistry and physical structures that can benefit materials science and engineering. Here, we demonstrate novel in situ correlative imaging of the X-ray Compton scattering computed tomography (XCS-CT) technique for studying this fundamental relationship. XCS-CT can image light elements that do not usually exhibit strong signals using other X-ray characterization techniques. This paper describes the XCS-CT setup and data analysis method for calculating the valence electron momentum density and lithium-ion concentration, and provides two examples of spatially and temporally resolved chemical properties inside batteries in 3D. XCS-CT was applied to study two types of rechargeable lithium batteries in standard coin cell casings: (1) a lithium-ion battery containing a cathode of bespoke microstructure and liquid electrolyte, and (2) a solid-state battery containing a solid-polymer electrolyte. The XCS-CT technique is beneficial to a wide variety of materials and systems to map chemical composition changes in 3D structures.

Divergent accumulation of microbial necromass and plant lignin phenol induced by adding maize straw to fertilized soils

Plant carbon (C) inputs and their subsequent microbial transformation affect the build-up process of soil organic C (SOC) pool. Nevertheless, there are knowledge gaps on how crop straw addition modifies SOC composition at molecular-level, especially in soils with different fertilization practices. Here, long-term fertilized Mollisols (unfertilized control, NF; inorganic fertilization, IF; inorganic fertilization plus manure, IFM) were incubated with or without maize straw addition in a 900-day field mesocosm experiment. The microbial necromass and plant lignin components contents were synchronously quantified based on amino sugar and lignin phenol biomarkers, respectively. And changes in SOC chemical composition were examined using solid-state 13C nuclear magnetic resonance spectroscopy. Relative to the NF treatment, long-term fertilization increased amino sugar and lignin phenol contents, and manure application enhanced the accumulation of plant lignin components more than that of microbial necromass. Compared with the NF treatment, the IF treatment decreased the relative proportion of alkyl C and SOC content, suggesting that changes in microbial necromass and lignin phenol were not always consistent with changes in SOC. For the NF and IF treatments, maize straw incorporation increased both amino sugar content and its contribution to SOC, indicating that microbial anabolism was important for SOC accumulation after adding maize straw in C-poor soils. For the IFM treatment, maize straw addition decreased lignin phenol content (27 %) and its contribution to SOC but increased the contribution of amino sugar to SOC, reflecting an enlarged contribution of microbial necromass to soil C pool formation under manure application after maize straw addition. The contribution of lignin phenol to SOC was decreased from days 360–900, whereas fungal necromass C content and the contribution of amino sugar to SOC were increased from days 360–900 under the IFM soil with maize straw addition, indicating that plant lignin components might be converted into fungal biomass and its necromass with increasing maize straw decomposition under manure application. Overall, we concluded that maize straw addition favored microbial immobilization in all fertilization treatments.

Investigation of Mazidagi phosphate ore in wet flue gas desulphurization

The employment of Mazidagi phosphate ore for wet flue gas desulphurization was investigated. The ore was exposed to sulfation processes in a three-phase double-stirred reactor to determine the effects of certain parameters on SO2 absorption. The absorption rate significantly increased with inlet SO2 concentration, gas flow rate, stirring speeds, and solid concentration but not with temperature. The absorption rate increases as the mass transfer coefficients and interface area value increase with stirring speeds. These parameters have also a prominent impact on the absorption rate depending on the dissolution rate of CaCO3. Based on these, the most effective parameters on SO2 absorption are liquid-phase stirring speed and suspension concentration, and the process is diffusion-controlled in the liquid phase. In addition, optimum conditions were determined, and then the ore was exposed to sulfation processes via a semi-batch operation mode. A comparison between raw and sulfated ore was examined for the changes in physical structure and chemical composition. Although the ratios of fluorapatite and carbonate-fluorapatite remained nearly constant, the ratio of calcite decreased significantly. It was determined from these investigations that the calcite in the phosphate ore has been converted into the CaSO3∙½H2O compound. Consequently, both the calcite in the phosphate ore was utilized effectively for wet flue gas desulphurization, and a phosphate-rich industrial product was obtained.

Aging effects on asphalt adhesive properties: molecular dynamics simulation of chemical composition and structural changes

ABSTRACT Asphalt aging is a natural process that causes changes in the properties of asphalt, particularly in asphalt adhesion. Previous studies show that the effect of aging on asphalt adhesion performance is not uniform and depends on the asphalt source and aging conditions. To investigate the effects of different SARA (saturates, aromatics, resins, and asphaltenes) ratios and structural changes on the adhesive properties of asphalt after aging, this study employs molecular dynamics simulation to calculate asphalt properties such as density, viscosity, and work of adhesion. The above properties were computed for 12 categories of asphalt molecules, individual SARA components, and asphalt models characterised by diverse SARA ratios, followed by a correlation analysis. The study reveals that asphalt aging increases density, viscosity, and adhesion to silica. The increase in polar functional groups, namely ketone and sulfoxide, is responsible for the enhanced adhesion of asphalt to silica due to the resulting increase in electrostatic potential energy. Different SARA ratios lead to different asphalt properties, with the RA/SA index ((asphaltene%+resin%)/(saturate% + aromatic%)) showing a better correlation with the properties. Positive correlations were observed among density, viscosity, and work of adhesion. This study advances our understanding of chemical and structural effects on aged asphalt properties.

In-situ non destructive investigation of contemporary outdoor bronze sculptures

Indoor investigations are commonly used to assess the causes and extent of damage to bronze artwork and cultural heritage items; however, these methods typically involve destructive sampling and outdoor bronze sculptures are typically heavy and large, hindering their transport. In this study, 16 contemporary bronze sculptures exposed to outdoor environments for a period exceeding 20 years were evaluated in-situ to develop a non-destructive prediction model that can identify types of corrosion and quantify the amount of corrosion on bronze sculptures that cannot be easily transported. The sculptures were classified into three groups according to their patina chromaticity, reflectivity, and chemical composition. The corrosion characteristics were found to be copper oxide and sulfide patinas. Chromaticity and reflectivity investigations revealed that the chemical composition changes of the patinas corresponded to the formation of corrosion products, thus showing a high potential for the identification of the type of corrosion. Portable XRF spectroscopy showed that the low error rate of Cu make its compositional behavior a good indicator in identifying the type of corrosion of sulfide and chloride patinas. Portable Raman spectroscopy was able to detect basic sulfides such as brochantite, antlerite, and cuprite. The corrosion types and corrosion products on the bronze sculptures could be identified using chromaticity and reflectivity, portable X-ray fluorescence, and portable Raman spectroscopy. The rapid insitu diagnosis of these corrosion attributes is expected to contribute to establishing conservation treatment plans in the future.

Reduction of polyketone membranes prepared by thermally induced phase separation with solvent co-extrusion for enhanced fouling resistance

This study utilized solvent co-extrusion technology and NaBH4 reduction to fabricate polyketone (PK) hollow fiber membranes with high water permeance and fouling resistance. Variations in reduction reaction time were explored to assess their impact on chemical composition, morphology, and properties. The results showed that the reduction reaction leads to the conversion of carbonyl groups on the membrane surface to hydroxyl groups, and with prolonged reaction time, the amount of hydroxyl groups on the membrane surface increases to a certain extent. The change in membrane chemical composition enhanced the hydrophilicity, while leaving the membrane morphology, mechanical properties, and separation performance largely unaffected. Static adsorption tests with bovine serum albumin (BSA) and E. coli exhibited distinct fouling behavior. While pristine PK membranes displayed significant BSA adsorption, PK reduction significantly reduced it. Both pristine and reduced PK membranes showed minimal E. coli attachment, likely due to weak interactions. Dynamic filtration tests demonstrated excellent flux recovery for reduced PK membranes, especially after 10 min of reduction, indicating superior fouling resistance with high flux recovery and low irreversible fouling, regardless of foulant type. These findings highlight a straightforward and efficient approach for producing high-performance membranes with exceptional fouling resistance suitable for practical applications.

Quality Evaluation of Polygonatum cyrtonema Hua Based on UPLC-Q-Exactive Orbitrap MS and Electronic Sensory Techniques with Different Numbers of Steaming Cycles.

In this study, electronic sensory techniques were employed to comprehensively evaluate the organoleptic quality, chemical composition and content change rules for Polygonatum cyrtonema Hua (PCH) during the steaming process. The results were subjected to hierarchical cluster analysis (HCA), principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA). These analyses revealed, from a sensory product perspective, overall differences in colour, odour and taste among the samples of PCH with different numbers of steaming cycles. Using the UPLC-Q-Exactive Orbitrap MS technique, 64 chemical components, including polysaccharides, organic acids, saponins and amino acids were detected in PCH before and after steaming. The sensory traits were then correlated with the chemical composition. From the perspectives of sensory traits, chemical composition, and multi-component index content, it was preliminarily deduced that carrying out five cycles of steaming and sun-drying was optimal, providing evidence for the quality evaluation of PCH during the steaming process.

Adsorption of Cu(II) and Ni(II) from Aqueous Solutions Using Synthesized Alkali-Activated Foamed Zeolite Adsorbent: Isotherm, Kinetic, and Regeneration Study.

Water pollution, particularly from heavy metals, poses a significant threat to global health, necessitating efficient and environmentally friendly removal methods. This study introduces novel zeolite-based adsorbents, specifically alkali-activated foamed zeolite (AAFZ), for the effective adsorption of Cu(II) and Ni(II) ions from aqueous solutions. The adsorbents' capabilities were comprehensively characterized through kinetic and isotherm analyses. Alkaline activation induced changes in chemical composition and crystalline structure, as observed via XRF and XRD analyses. AAFZ exhibited a significantly larger pore volume (1.29 times), higher Si/Al ratio (1.15 times), and lower crystallinity compared to ZZ50, thus demonstrating substantially higher adsorption capacity for Cu(II) and Ni(II) compared to ZZ50. The maximum monolayer adsorption capacities of ZZ50 and AAFZ for Cu(II) were determined to be 69.28 mg/g and 99.54 mg/g, respectively. In the case of Ni(II), the maximum monolayer adsorption capacities for ZZ50 and AAFZ were observed at 48.53 mg/g and 88.99 mg/g, respectively. For both adsorbents, the optimum pH for adsorption of Cu(II) and Ni(II) was found to be 5 and 6, respectively. Equilibrium was reached around 120 min, and the pseudo-second-order kinetics accurately depicted the chemisorption process. The Langmuir isotherm model effectively described monolayer adsorption for both adsorbents. Furthermore, the regeneration experiment demonstrated that AAFZ could be regenerated for a minimum of two cycles using hydrochloric acid (HCl). These findings highlight the potential of the developed adsorbents as promising tools for effective and practical adsorption applications.

Exploring Endogenous Processes in Water Supply Systems: Insights from Statistical Methods and δ18O Analysis

Water used for water supply undergoes numerous changes that affect its composition prior to entering the water supply system (WSS). Once it enters the WSS, it is subject to numerous influences altering its physical and chemical composition, redox potential, and microbial quality. Observations of water quality parameters at different locations within the WSS indicate that it is justified to assume that these processes take place from the source to the end user. In this study, we used the results of routine everyday analyses (EC, T, pH, ORP, chloride, nitrate, nitrite, ammonium, and bacteria) supplemented by experimental data from a one-year sampling campaign assessing the main cations and anions and stable isotopes δ2H and δ18O. Through these data, the statistical significance of the differences between the concentrations of the basic water quality parameters among different WSS locations was determined, together with the water retention time in the system. The results indicate minor changes in water chemical composition within the observed WSS, remaining below the prescribed Maximum Contaminant Level (MCL) for human consumption. However, factors such as water retention time, CaCO3 deposition, pH fluctuations, and bacterial growth may influence its suitability, which necessitates further investigation into potential risks affecting water quality.

Quality evaluation and identification of Houttuynia cordata bleached with sodium metabisulfite based on whole spectrum metabolomics

Houttuynia Cordata (HC) is a widely distributed plant in Asia and is used extensively for both food and medicinal purposes. A preliminary investigation found that HC is often bleached with sodium metabisulfite solution during its field processing, leading to health risks. In this study, the effects of sodium metabisulfite on the quality of HC were comprehensively evaluated using volatile and non-volatile targeted metabolomic methods. The results revealed a positive correlation between the extent of chemical composition changes and the bleaching time. These notable changes mainly occurred at the initial stage of bleaching. Subsequently, an untargeted UPLC/Q-TOF MS method was used to explore the potential chemical bleaching markers in bleached HC. The marker 1-hydroxy-3-oxodecane-1-sulfonic acid was subsequently prepared, isolated, and identified. Market sample verification further validated the accuracy and effectiveness of this marker.

The synergistic potential of orange peel extract: A comprehensive investigation into its phenolic composition, antioxidant, antimicrobial, and functional fortification properties in yogurt

The study explores the potential of orange peel extract (OPE) as a versatile natural resource, focusing on its phenolic composition, antioxidant, and antibacterial properties, as well as its application in fortifying yogurt. Analysis revealed significant concentrations of phenolic compounds in OPE. OPE exhibited notable antibacterial efficacy against pathogenic bacteria, particularly marine Escherichia coli, with synergistic effects observed when combined with Amikacin. Incorporating OPE into yogurt led to changes in chemical composition, enhancing total proteins, fat, and ash content. Fortified yogurt showed increased antioxidant activity and potential anti-cancer properties against HCT116 cell lines. In conclusion, OPE emerges as a rich source of bioactive compounds with diverse applications, from its antioxidant and antibacterial properties to its potential in fortifying functional foods like yogurt. This comprehensive exploration provides valuable insights into the multifaceted benefits of OPE, paving the way for its utilization in various industries and health-related applications.

Effect of Electrolytic Plasma Polishing on Surface Properties of Titanium Alloy

Electrolytic plasma polishing (EPPo) is an advanced metal surface finishing technology with high quality and environmental protection that has broad application prospects in the biomedical field. However, the effect of EPPo on surface properties such as corrosion resistance and the wettability of biomedical titanium alloys remains to be investigated. This paper investigated the changes in surface roughness, surface morphology, microstructure, and chemical composition of Ti6Al4V alloy by EPPo and their effects on surface corrosion resistance, wettability, and residual stress. The results showed that Ra decreased from 0.3899 to 0.0577 μm after EPPo. The surface crystallinity was improved, and the average grain size increased from 251 nm to more than 800 nm. The oxidation behavior of EPPo leads to an increase in surface oxygen content and the formation of TiO2 and Al2O3 oxide layers. EPPo can significantly improve the corrosion resistance and wettability of titanium alloy in simulated body fluid and eliminate the residual stress on the sample surface. The surface properties are enhanced not only by the reduction in surface roughness but also by the formation of a denser oxide film on the surface, changes in the microstructure, an increase in surface free energy, and the annealing effect developed during EPPo. This study can provide guidance and references for applying EPPo to biomedical titanium alloy parts.

Performance evolution and mechanism of asphalt crack sealant under UV aging: A continuity study

Asphalt crack repair materials, known as crack sealants, are directly exposed to ultraviolet (UV) radiation in asphalt pavements. This exposure causes the gradual aging and deterioration of both their surface and internal properties. To study this phenomenon, the sealant was subjected to UV irradiation for a range of 0–385 hours, with the basic properties of the aged sealant tested every 55 hours. Several techniques were employed to investigate the changes in the internal chemical composition of the sealant, including Fluorescence microscopy (FM), gel permeation chromatography (GPC) and Fourier transform infrared spectroscopy (FT-IR). The results revealed that the UV aging of the sealant mainly occurs in the thinner surface layer, which becomes progressively lighter in color. Notably, obvious surface cracks form after aging process. The cone penetration and softening point of the sealant exhibit an exponential or logarithmic change corresponding to the aging time. The most pronounced changes occur during the early stages of UV aging, with the properties tending to stabilize after approximately 220 h of aging. In addition, the FM images showed that the dispersed polymer particles within the sealant gradually transform into a continuous network structure after aging over time. The GPC spectrum of the aged sealant shifts to the left, indicating an increase in molecular weight, particularly in the polymer modifier. This is consistent with the transformation observed in the FT-IR analysis, which demonstrates that UV irradiation leads to the breaking and recombination of polymer chemical bonds in the sealant. The FT-IR analysis reveals the conversion of monosubstituted benzene to polysubstituted benzene in the polymer modifier, which also correlates with the formation of the network structure observed in the FM images and the increase in molecular weight detected in the GPC spectrum of the polymer modifier.