Changes In Chemical Composition Research Articles

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.

Effects of Exocellobiohydrolase CBHA on Fermentation of Tobacco Leaves.

The quality of tobacco is directly affected by macromolecular content, fermentation is an effective method to improve biochemical properties. In this study, we utilized CBHA (cellobiohydrolase A) glycosylase, which was expressed by Pichia pastoris, as an additive for fermentation. The contents of main chemical components of tobacco leaves after fermentation were determined, and the changes of microbial community structure and abundance in tobacco leaves during fermentation were analyzed. The relationship between chemical composition and changes in microbial composition was investigated, and the function of bacteria and fungi in fermentation was predicted to identify possible metabolic pathways. After 48 h of CBHA fermentation, the contents of starch, cellulose and total nitrogen in tobacco leaf decreased by 17.60%, 28.91% and 16.05%, respectively. The microbial community structure changed significantly, with Aspergillus abundance decreasing significantly, while Filobasidum, Cladosporium, Bullera, Komagataella, etc., increased in CBHA treated group. Soluble sugar was most affected by microbial community in tobacco leaves, which was negatively correlated with starch, cellulose and total nitrogen. During the fermentation process, the relative abundance of metabolism-related functional genes increased, and the expressions of cellulase and endopeptidase also increased. The results showed that the changes of bacterial community and dominant microbial community on tobacco leaves affected the content of chemical components in tobacco leaves, and adding CBHA for fermentation had a positive effect on improving the quality of tobacco leaves.

Sleep promoting and omics exploration on probiotics fermented Gastrodia elata Blume

Fermenting Chinese medicinal herbs could enhance their bioactivities. We hypothesized probiotic-fermented gastrodia elata Blume (GE) with better potential to alleviate insomnia than that of unfermented, thus the changes in chemical composition and the insomnia-alleviating effects and mechanisms of fermented GE on pentylenetetrazole (PTZ)-induced insomnia zebrafish were explored via high-performance liquid chromatography (HPLC) and mass spectroscopy-coupled HPLC (HPLC-MS), phenotypic, transcriptomic, and metabolomics analysis. The results demonstrated that probiotic fermented GE performed better than unfermented GE in increasing the content of chemical composition, reducing the displacement, average speed, and number of apoptotic cells in zebrafish with insomnia. Metabolomic investigation showed that the anti-insomnia effect was related to regulating the pathways of actin cytoskeleton and neuroactive ligand-receptor interactions. Transcriptomic and reverse transcription qPCR (RT-qPCR) analysis revealed that secondary fermentation liquid (SFL) significantly modulated the expression levels of neurod1, msh2, msh3, recql4, ercc5, rad5lc, and rev3l, which are mainly involved in neuron differentiation and DNA repair. Collectively, as a functional food, fermented GE possessed potential for insomnia alleviation.

In situ high temperature transmission electron microscopy on melting mechanism of secondary copper smelting slag

A new technique for investigations in nano-scale is applied to secondary copper smelting slag with the aim to understand melting mechanism and phase development within the material: in situ transmission electron microscopy at high temperatures. Heating the material step by step with accompanying EDX analysis allows detailed tracking of phase transformations, including changes in chemical composition. The behavior of Cu nano-spheres as well as Fe and Zn in different phases is described in detail. Evaporation of Cu, Fe and Zn is compared to available thermodynamic data, showing relatively good agreement for Cu and Fe, but different results for Zn. The observation of liquid Fe formation is a new phenomenon, which needs further investigation. High temperature transmission electron microscopy is found to be a suitable method for certain research questions, when taking limiting factors like vacuum conditions and electron beam effects into account.

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

Temporally-resolved decomposition of Ti0.12Al0.21B0.67 thin films at 1000 °C

The thermal stability of stoichiometric Ti0.12Al0.21B0.67 thin films synthesized by magnetron sputtering was investigated by vacuum annealing at 1000 °C for 1 and 3 h. The as-deposited and post-annealed films were compared regarding changes in chemical composition, phase formation, and morphology.X-ray diffraction (XRD) data indicate the formation of a single-phase solid solution in the as-deposited Ti0.12Al0.21B0.67 thin film. After annealing for 1 h, scanning transmission electron microscopy (STEM), energy-dispersive X-ray mapping (EDX), and atom probe tomography (APT) investigations reveal segregation into Al- and Ti-rich (Ti,Al)B2 domains, consistent with spinodal decomposition. Furthermore, the formation of AlB12 with a concomitant reduction in Al concentration from 20.9 to 16.8 at. %, likely by evaporation, indicate the decomposition of Al-rich (Ti,Al)B2 domains during annealing for 1 h.Analysis of the film after annealing for 3 h shows evidence for continued spinodal decomposition as well as for further decomposition of Al-rich (Ti,Al)B2 domains, leading besides the formation of AlB12 to a reduction in Al concentration to 12.5 at. % by Al evaporation. The observed phase formation trend during in situ transmission electron microscopy (TEM) studies at 1100 °C is consistent with the above discussed decomposition processes. The here identified thermal stability limit, revealed with spatially resolved structure and composition probes, confines the application temperature range of Ti0.12Al0.21B0.67 in vacuum to temperatures <1000 °C and underlines that thermal stability investigations solely based on XRD data result in an overestimated thermal stability.

The Initial Assessment of the Possibility of Simulation Fire Standard Curve in the Electric Furnace with the Assessment of Chemical Composition Changes in Steel after Cooling Phase

The Initial Assessment of the Possibility of Simulation Fire Standard Curve in the Electric Furnace with the Assessment of Chemical Composition Changes in Steel after Cooling Phase

The role of arabinoxylan purified from wheat bran in bread and biscuits: Impacts on digestibility and colonic fermentability in vitro

In this study, arabinoxylan (AX) isolated from wheat bran was used to prepare AX-fortified bread and biscuits, and the effects of the amount and method of AX addition on the nutritional properties of baked products were investigated through simulated digestibility and colonic simulated fermentability analysis in vitro. The purified AX demonstrated a high total sugar content (92.75%), high molecular weight (Mw) (669.8 kDa), low polymer dispersity index (PDI) and low arabinose to xylose (A/X) ratio (1.21). In vitro digestibility test indicated that AX addition could dose-dependently inhibit the starch digestibility in both bread and biscuits. Most importantly, it could also dose-dependently transfer more starch and protein into the colon through the gastrointestinal tract, leading to the changes in total amount and chemical composition of food residues. Results from the in vitro fermentability test showed that alterations in the composition of food residue affected its fermentability: a high relative ratio of carbohydrate to protein could enhance its prebiotic effect. This study provides valuable insights into the role of dietary fibres in baked foods, aiming to achieve precise nutrition for high-fibre food products.

EVALUATION OF THE EFFECT OF AIR ON THE HYDRATION SYSTEM OF THE AXIAL PISTONS

This study investigates the effect of air exposure on the hydration system of axial pistons, critical components in various hydraulic systems. The hydration process, which is integral to the functionality and longevity of axial pistons, is potentially sensitive to environmental factors such as air. This research aims to elucidate the effect of air on the hydration kinetics, surface properties and performance of axial pistons. Experimental studies were conducted using controlled environments to analyze the hydration behavior of piston samples under varying degrees of air exposure. Techniques such as surface microscopy, chemical analysis and mechanical testing were used to comprehensively evaluate the effects. Preliminary findings indicate that exposure to air significantly affects the hydration kinetics of axial pistons, affecting the rate and extent of hydration. Surface analysis reveals changes in surface morphology and chemical composition indicating changes in the air-induced hydration process. Moreover, mechanical testing reveals notable differences in the performance characteristics, including wear resistance and friction properties, of pistons exposed to varying weather environments. Overall, this study underlines the importance of considering air exposure in understanding and optimizing the hydration system of axial pistons and provides valuable information for improving hydraulic system efficiency and reliability. Keywords: axial pistons, hydration system, piston, hydraulic machine, rotor.

Investigation on laser cladding Fe-based gradient coatings with hierarchical enhanced wear resistance on U75V railway steel

This study focused on the multilayer laser cladding of 15–5 precipitation hardening (PH) steel coating on U75V railway steel for improved surface performance. The effect of pearlitic substrate dilution action with high carbon content on microstructures and wear performance of PH steel coating with four deposited layers was investigated. Results showed that each cladding layer consisted of a similar multiphase mixture of martensite, retained austenite, and NbC carbides in the case of stepwise changes in chemical compositions induced by dilution effects. The wear resistance of the multilayered PH steel coating is closely related to the deposited layer number, reflected in a gradient increase in the wear rate with the increasing cladding layers. A comparative analysis against the U75V substrate showed substantial wear rate reductions of approximately 95 % and 4.5 % in the first and fourth layers, respectively. Besides, the cross-sectional microstructures were analyzed in detail to reveal the underlying friction-induced microstructural evolution of the gradient coating. The refinement of martensite laths controlled by dislocation reaction and the friction-induced austenite to martensite transformation was responsible for the superior wear resistance. The current experimental results could provide a new strategy for designing hierarchical enhanced wearable gradient coating for surface modification in railway components.

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.

Coupled thermo-hydro-chemical modeling of accelerated carbonation of cement-based materials: Application to CO2 uptake

The use of CO2-rich hot gases from cement plants or combustion processes is considered as an attractive method to accelerate the carbonation of recycled concrete aggregates (RCA). However, there is limited knowledge regarding the kinetics and mechanisms of accelerated carbonation induced by wet gas with a temperature of approximately 80 °C. Water transport and temperature influence several parameters of the carbonation of cement-based materials, thus understanding and predicting their overall effect remains complex. The present study combines experimental and numerical investigations into the effects of temperature on carbonation processes. The experimental study focuses on understanding the effects of temperature on the evolution of the carbonation front, changes in chemical composition, and moisture transport within a cement-based material during carbonation in controlled conditions. The experimental data obtained serve as calibration parameters for a thermo-hydro-chemical coupled model of carbonation. The carbonation model incorporates heat transfer between the cement-based material and the external environment, considering the influence of temperature on water transfer, as well as the dissolution and carbonation of hydration products.

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.

Changes in Garlic Quality during Fermentation under Different Conditions.

One of the garlic processing methods is fermentation, which produces black garlic with completely different chemical, physical, sensory, culinary, and health-enhancing properties. Our study aimed to compare the influence of various processing conditions on the quality indicators of black garlic (BG). Samples of white garlic (WG) were placed in laboratory climatic chambers. BG1 samples were packed in plastic bags and vacuumed, BG2 and BG3 samples were packed in textile mesh bags. BG1 samples were fermented in 70% humidity at 50 °C for 28 days, BG2 samples in 85% humidity at 60 °C for 99 days, and BG3 samples in 80% humidity at 80 °C for 14 days. The dependence of changes in chemical composition, color, and texture of garlic on fermentation conditions was analyzed. Proximate composition analyses and antioxidant activity of WG and BG were performed using standard methods. It was established that regardless of the fermentation conditions, BG's chemical composition became richer than WG's. They significantly increased vitamin C content (1.5-5.8 fold), titratable acidity (14.7-21.0 fold), protein (1.4-3.2 fold), fiber (4.6-7.0 fold), and ash (1.2-3.9 fold) content, amount of total phenolic compounds (6.6-9.6 fold) and antioxidant activity (5.3-9.9 fold). Fermented garlic turned dark in color and soft and sticky in texture. The higher fermentation temperature (80 °C) but the shorter time (14 days) had the greatest positive effect on the quality of black garlic.

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.

Changes in the Chemical Composition of Polyethylene Terephthalate Under UV Radiation in Various Environmental Conditions.

Polyethylene terephthalate has been widely used in the packaging industry. Degraded PET micro-nano plastics could pose public health concerns following release into various environments. This study focuses on PET degradation under ultraviolet radiation using the NIST SPHERE facility at the National Institute of Standards and Technology in saturated humidity (i.e., ≥ 95 % relative humidity) and dry conditions (i.e., ≤ 5 % relative humidity) with varying temperatures (30 °C, 40 °C, and 50 °C) for up 20 days. ATR-FTIR was used to characterize the chemical composition change of degraded PET as a function of UV exposure time. The results showed that the cleavage of the ester bond at peak 1713 cm-1 and the formation of the carboxylic acid at peak 1685 cm-1 are significantly influenced by UV radiation. Furthermore, the formation of carboxylic acid was considerably higher at saturated humidity and 50 °C conditions compared to dry conditions. The ester bond cleavage was also more pronounced in saturated humidity conditions. The novelty of this study is to provide insights into the chemical degradation of PET under environmental conditions, including UV radiation, humidity, and temperature. The results can be used to develop strategies to reduce the environmental impact of plastic pollution.