Changes In Physical Properties Research Articles

Effect of airborne particle abrasion treatment of two types of 3D-printing resin materials for permanent restoration materials on flexural strength.

This study aimed to assess the effects of airborne-particle abrasion (APA) on the flexural strength of two types of 3D-printing resins for permanent restoration. Two types of 3D printing resins (urethane dimethacrylate oligomer; UDMA, ethoxylated bisphenol-A dimethacrylate; BEMA) constituting different components were printed. The specimen surfaces were subjected to APA using 50 and 110µm alumina particles under different pressures. The three-point flexural strength was measured for each surface treatment group, and a Weibull analysis was performed. Surface characteristics were analyzed via surface roughness measurements and scanning electron microscopy. Dynamic mechanical analysis and nano-indentation measurements were limited to the control group. The three-point flexural strength according to the surface treatment was significantly lower in the UDMA group for large particle sizes and at high pressures; the BEMA group demonstrated low flexural strength for large particle sizes regardless of the pressure. After thermocycling, the flexural strengths of UDMA and BEMA significantly decreased in the group subjected to surface treatment. The Weibull modulus and characteristic strength of UDMA were higher than those of BEMA under different APA and thermocycling conditions. As the abrasion pressure and particle size increased, a porous surface formed, and the surface roughness increased. Compared with BEMA, UDMA featured a lower strain, greater strain recovery, and a negligible increase in modulus according to strain. Thus, surface roughness increased with the sandblasting particle size and pressure of the 3D-printing resin. Hence, a suitable surface treatment method to improve adhesion can be determined by considering physical property changes.

In Situ and Real-Time Mold Flux Analysis Using a High-Temperature Fiber-Optic Raman Sensor for Steel Manufacturing Applications

Continuous casting in steel production uses specially developed oxyfluoride glasses (mold fluxes) to lubricate a mold and control the solidification of the steel in the mold. The composition of the flux impacts properties, including basicity, viscosity, and crystallization rate, all of which affect the stability of the casting process and the quality of the solidified steel. However, mold fluxes interact with steel during the casting process, resulting in flux chemistry changes that must be considered in the flux design. Currently, the chemical composition of mold flux must be determined by extracting flux samples from the mold during casting and then processing these samples offline to estimate the working chemical composition and, therefore, the expected properties of the flux. Raman spectroscopy offers an alternative method for performing flux analysis with the potential to perform measurements online during the casting process. Raman spectroscopy uniquely identifies specific chemical bonds and symmetries in the glassy flux by revealing peaks that are a fingerprint of the vibration modes of molecules in the flux. The intensities of specific peaks in Raman spectra can be correlated with the chemical composition of the melt and associated properties such as basicity and viscosity. This paper reports on the first use of a portable fiber-optic Raman sensor for <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">in situ</i> Raman spectroscopic measurements of molten flux at 1400°C. The work demonstrates the advantages of fiber-optic Raman spectroscopy to document the structure and chemical composition of flux samples at temperatures typically encountered in the mold during continuous caster operation. Experimental results demonstrate that the composition-dependent Raman signal shifts can be detected at caster operating temperatures, and the use of high-temperature Raman analysis for in-line flux monitoring shows significant promise for the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">in situ</i> detection of changes in flux composition and physical properties during casting.

Biodegradable Nanogels for Dermal Applications: An Insight

Abstract: Biodegradable nanogels in the biomedical field are emerging vehicles comprising dispersions of hydrogel nanoparticles having 3D crosslinked polymeric networks. Nanogels show distinguished characteristics including their homogeneity, adjustable size, low toxicity, stability in serum, stimuli-responsiveness (pH, temperature, enzymes, light, etc.), and relatively good drug encapsulation capability. Due to these characteristics, nanogels are referred to as nextgeneration drug delivery systems and are suggested as promising carriers for dermal applications. The site-specific delivery of drugs with effective therapeutic effects is crucial in transdermal drug delivery. The nanogels made from biodegradable polymers can show external stimuliresponsiveness which results in a change in gel volume, water content, colloidal stability, mechanical strength, and other physical and chemical properties, thus improving the site-specific topical drug delivery. This review provides insight into the advances in development, limitations, and therapeutic significance of nanogels formulations. It also highlights the process of release of drugs in response to external stimuli, various biodegradable polymers in the formulation of the nanogels, and dermal applications of nanogels and their role in imaging, anti‐inflammatory therapy, antifungal and antimicrobial therapy, anti‐psoriatic therapy, and ocular and protein/peptide drug delivery.

Fundamental Physical Property Changes of Aged Binders According to the Rejuvenator’s Content

Fundamental Physical Property Changes of Aged Binders According to the Rejuvenator’s Content

A phase transition model in dual-amorphous water undergoing liquid–liquid transition

An in-depth understanding of liquid–liquid phase transition (LLPT) in condensed water will gain insight into anomalous behaviors of dual-amorphous condensed water. Despite numerous experimental, molecular simulation, and theoretical studies, it is yet to achieve a widely accepted consensus with convinced evidence in the condensed matter physics for two-state liquid–liquid transition of water. In this work, a theoretical model is proposed based on the Avrami equation, commonly used to describe first-order phase transitions, to elucidate complex homogeneous and inhomogeneous condensation from high-density liquid (HDL) water to low-density liquid (LDL) water for both pure and ionic dual-amorphous condensed water. This model unifies the coupling effects of temperature and electrolyte concentration based on the new theoretical framework. The Adam–Gibbs theory is then introduced to characterize the synergistic motion and relaxation behavior of condensed water. Variations in the configurational entropy under electrostatic forces are further explored, and an analytical 2D cloud chart is developed to visualize the synergistic effect of temperature and electrolyte concentration on the configurational entropy of ionic water. The constitutive relationships among viscosity, temperature, and electrolyte concentration are derived to analyze their synergistic effects under different condensation fractions of LDL and HDL. The Stokes–Einstein relation and free volume theory are further used to analyze diffusion coefficients and densities (or apparent density) during both pure and ionic LLPT. Finally, theoretical results obtained from these models are compared with experimental results reported in literature to validate the accuracy and applicability of the proposed models, which offer significant benefits and advancements in effectively predicting physical property changes of dual-amorphous condensed water.

Alterations in pore and fracture structure of coal matrix and its surrounding rocks due to long-term CO2-H2O-rock interaction: Implications for CO2-ECBM

To comprehend the impacts of coal reservoir physical property change because of exposure to acidic environment formed by CO2 on validity, safety, and stability of CO2– ECBM, the CO2-H2O-rock interaction was conducted on a high-rank coal and surrounding rocks, i.e., sandstone roof and mudstone floor, at 318.15 K and 12 MPa for a period of 240 days. Multiple characterizations were also conducted to reveal the alterations in inorganic minerals as well as pores and fractures of coal matrix and surrounding rocks. Results indicate that the long-term CO2-H2O-rock interaction leads to both dissolution and precipitation of inorganic minerals of coal matrix, sandstone roof, and mudstone floor. Despite coal matrix swelling found during the interaction, mineral dissolution acts dominant role toward rising full-scale pores and fractures of coal matrix, thereby remarkably increasing its porosity and absolute permeability. Such changing trends are also noticed in sandstone roof. As for mudstone floor, mineral dissolution effect also upgrades its micro- and mesopores, but mineral precipitation dramatically reduces its macropores. Additionally, the interaction increases absolute permeability of mudstone floor by three orders of magnitude because of newly-formed fractures. The aforementioned alterations in pores and fractures could further strengthen storage potential of coal seams but weaken sealing performance of surrounding rocks to injected CO2. Overall, metamorphic degree of coal matrix and inorganic mineral compositions of surrounding rocks are crucial for choosing candidate coal reservoirs for implementing CO2-ECBM.

Characterization of Corn Starch Granules Modified by Glucan 1,4‐α‐Maltotriohydrolase from Microbacterium imperiale

AbstractIn this study, glucan 1,4‐α‐maltotriohydrolase (AMTS) is used to modify corn starch granules to elucidate the structural and physical property changes following AMTS modification. The degree of hydrolysis (DH) of granular corn starch is modulated by adding various amounts of AMTS. Pore structures with more pores, deep channels, and cavities in starch granules with extended hydrolysis are observed by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). The short‐range ordered structure, lamellar structure, and crystalline structure are significantly enhanced under moderate AMTS modification, and then slightly decreased with further modification. These structural changes significantly improve oil and water absorption capacities, decrease solubility and swelling power, diminish pasting properties, and lower the digestibility of granular corn starch. When AMTS interferes with the starch system, the specific surface area of granular starch gradually increases with extended hydrolysis, with the maximum being almost 4.6‐fold that of native starch. All these results suggest AMTS hydrolysises of corn starch granules through an “inside‐out” pattern, preferential hydrolysis of the amorphous region, and subsequent alternate hydrolysis of the amorphous and crystalline regions. Overall, AMTS is a potential granular starch hydrolase for producing porous starch used as the carrier material in a variety of food applications.

Statement of the problem of simulation of shear processes in low-colusion plastics oils

The article deals with the issue of modelling shear processes in plastic soils. The peculiarity and main difficulty of modelling landslide processes is the need to take into account a large number of various natural and technogenic influences on the slope, each of which can significantly affect its overall stability. It is also important to take into account not only the current state of the slope but also the forecasting of factors that may affect it over time. In this case, it may be justified to create complex models that include several interconnected sub-models to describe various physical phenomena. Considering the complexity of calculations to determine the stability of the slope or shear pressure on engineering protection structures, it is not surprising that all calculation methods rely on some assumptions when building calculation models to describe physical phenomena and reduce the complexity of calculations. However, it should be noted that the modelling of the non-linear behaviour of soils and the use of models that more accurately describe physical phenomena and processes occurring on slopes can significantly affect the results of calculations.&#x0D; The article presents the main relationships of the mathematical model of elastic-plastic deformation of soils. The given ratios allow taking into account such phenomena as dilatancy and contraction, which makes it possible to more accurately model the stress-strain state of the soil medium, the distribution of pressure in the soil, taking into account the change in physical and mechanical properties during the deformation process.&#x0D; In the article, the finite element method is chosen as the most effective method of numerical modelling of shear processes. Certain aspects of the implementation of calculations based on a complex model and the justification for determining the coefficient of slope stability within the framework of this method are presented.

The impact of pollutant emissions from co-incineration of industrial waste in municipal solid waste incinerators

A large amount of industrial solid waste (including waste plastics, textiles, wood, etc., which are byproducts of industrial production) urgently needs to be treated. Incineration is undoubtedly the most efficient and convenient method. The existing municipal solid waste incineration plants can be transformed to burn such industrial wastes. However, the potential risks associated with high levels of heavy metals in industrial waste and the air pollution caused by co-incineration pose significant challenges to the co-incineration disposal of industrial solid waste. The change of physical and chemical properties of municipal solid waste and the emission characteristics of flue gas pollutants after co-incineration of industrial waste were studied by means of material flow simulation and experiment. In addition, experiments were designed to study the effects of temperature, calcium sulfur ratio and chlorine content on heavy metal emission during the incineration of industrial waste. The results showed that co-incineration of a certain proportion of industrial waste significantly increased the calorific value of municipal solid waste, but excessive mixing of plastic and paper industrial waste would increase the ash content. Co-incineration of plastic industrial waste can significantly increase HCl, and with the increase of temperature, the transformation of Cl to HCl is more thorough. The increase of temperature can promote the migration of Cr, Pb and Se elements to the gas phase. When Cr, Pb, and Se elements are present in the gas phase, they can combine with other gases and aerosols to form particulate matter and toxic substances, causing air pollution. When Ca/S is 1, Ba, Mn, Ni, Zn can effectively reduce the retention rate of elements in the ash. Under certain conditions, chlorine in industrial waste plastics will react with Zn to form tiny particles and low boiling point chlorides, which will increase its volatility. The mineral components in the ash can also be used for making ceramsite and building materials. These results will provide reference for the pollutants controlling during co-incineration of industrial waste and municipal solid waste process.

Effect of mineralogical variations on physico-mechanical and thermal properties of granitic rocks

The present study aims to explain the geochemical and mineralogical details of the granitic rock types in Gabal EL-Faliq area, South Eastern Desert of Egypt, in relation to geotechnical engineering and their suitability as dimension stones. The objective of the current research was achieved through two steps; the first step involved geological studies such as the petrographic, geochemical, and mineralogical investigations. The second and applicable step involved the geotechnical assessment of the studied rocks by measuring their engineering properties such as physical, mechanical, and thermal expansion properties. The petrographic investigation revealed that the studied granitic rocks are divided into two main classes: (1) gneissose granites (Biotite–Perthite) of medium to fine-grained size and (2) alkali-feldspar granites of coarse to medium-grained size. Mineralogically, the studied rocks are composed mainly of albite, orthoclase and quartz in varying proportions, along with some accessory minerals such as apatite and rutile in addition to some minor quantities of iron-group minerals such as hematite and ilmenite. The engineering properties showed that the maximum water absorption and apparent porosity values are 0.34% and 0.77%, respectively, while the minimum bulk density is 2604.03 kg/m3. The compressive strength ranges from 999.68 to 2469.10 kg/cm2, while the abrasion resistance varies from 29.67 to 54.64 Ha. The increase in albite content led to an increase in water absorption while a decrease in bulk density and compressive strength. The increase in the grain size led to an increase in apparent porosity and a decrease in mechanical properties. A Great variation in the expansion coefficient as well as the length change, occurs under changes in temperature, mineral composition, and physical properties. The increase in heating temperatures caused an insignificant increase in linear thermal expansion with a maximum value of 0.0385% at 100 °C. These results indicated the suitability of the studied granites as dimension stones for use in indoor and outdoor decorative purposes (cladding/paving) under variable temperature conditions.

Spatial Distribution and Main Controlling Factors of Nitrogen in the Soils and Sediments of a Coastal Lagoon Area (Shameineihai, Hainan)

As the relationship between the spatial distribution characteristics and physicochemical properties of nitrogen in lagoon soil and sediment is still unclear, we obtained and systematically analyzed soil and sediment samples from the surroundings of a lagoon in the Shamei Inland Sea, Qionghai City, Hainan Province. The spatial distribution of nitrogen forms was investigated, and the soil physicochemical properties that predominantly influenced the nitrogen distribution were characterized. The results were as follows: (1) There are differences in nitrogen content in the soil and sediment around the Shamei Inland Sea. The total nitrogen levels in the Shamei Inland Sea were low, and organic nitrogen was dominant. The soil samples showed higher organic nitrogen concentrations than the sediment samples. Thus, the characteristics of dispersion in offshore waters differ from those in lagoons. The average contents of nitrate, ammonium and nitrite in the soil around the lagoon were higher than those in the sediment, and they were especially high in the lagoon mouth area. The nitrate content was greater in the estuary area in the northwest of the lagoon, and the contents of ammonium and nitrite in the estuary area in the south of the lagoon were the highest. (2) The changes in the basic physical and chemical properties of the soils and sediments in the Shamei Inland Sea area have an important coupled effect on the enrichment, preservation and mineralization of nitrogen. Through redundancy analysis (RDA), the explanatory degree of the organic matter content in relation to the nitrogen content was determined to be approximately 17.2%, contributing 80.9% of all nitrogen. The organic matter content, cation exchange capacity and clay content were positively correlated with the nitrogen content, indicating that changes in the basic physical and chemical properties of the soil and sediment had an important impact on nitrogen enrichment, preservation and mineralization processes. The total nitrogen and the organic matter content, cation exchange capacity and clay content of the soil and sediment were positively correlated. The high proportion of nitrate in the soil, the high proportion of ammonium in the sediment, the heavy texture of the sediment, poor soil ventilation and weak nitrification were related.

Changes in physical properties of some proprietary safflower (Carthamus tinctorius L.) cultivars after film coating application

Safflower is one of the economically important oil plants. There are some studies on safflower, but none on its seed properties. This study was carried out in the Biosystem Engineering laboratories of the Faculty of Agriculture of Bingöl University in 2021. The seeds of four different proprietary safflower cultivars were randomly sampled, and some of their physical properties were examined under two separate groups, that is, control and film-coated. The film coating material was applied in a single layer, and its effects on the seed size were compared between the study groups. The coating dose should be at a level that will not adversely affect the germination and emergence performance of the seed. As a result of the study, it was found that the safflower seeds were long and oval in shape. This study is important in that its results will help the researchers carry out mechanization and breeding studies on safflower. Bangladesh J. Sci. Ind. Res. 58(2), 129-132, 2023

Morphological optimized CeO2 and Cu-doped CeO2 nanocrystals for hydrogen production by solar photo-thermochemical water splitting based on surface photoinduced oxygen vacancies

Photo-thermochemical (PTC) reaction produces hydrogen by water splitting through the consumption of surface photoinduced oxygen vacancies (VOs). In this study, CeO2 and Cu-doped-CeO2 were synthesized with typical different morphologies of nanorods and nanospheres and different crystallite sizes. These factors, i.e. microstructure, crystalline size and Cu doping were proven to influence the physical properties and photoresponse performance of CeO2 which affected the generation of surface photoinduced VOs and their reactions of hydrogen production in PTC. Cu-doped CeO2 nanospheres with smaller crystallite size demonstrated the best catalytic activity with the largest H2 yield of 18.4 μmol g-1h−1. The electron paramagnetic resonance and Ultraviolet–visible diffuse reflection spectroscopy analysis showed that the VOs generation of nanospheres was strengthened compared to nanorods when the physical characteristics were similar. The positive correlation between the change in physical properties and yield supports its importance in VOs consumption in the thermochemical process. The smaller crystallite size of the nanospheres exhibited better porous properties and specific surface area, which facilitated thermochemical reaction. The doping significantly reduces the band gap of the sample, enhances the light absorption capacity and significantly increases the H2 yield of CeO2.

Spatial variation of physical and mechanical properties of tailings under different rainfall intensities and the interaction pattern

With the continuous mining, a huge amount of mine waste has accumulated in tailing dams in China. The increasing frequency of abnormal rainfall in China poses a significant threat to the stability of tailings dams. It is important to study spatial variation of physical and mechanical properties of tailings for the process of dam destabilization due to rainfall. The Luomukeng tailings dam, Jiangxi province, China, was selected as the research object and the changes of physical parameters of tailings at different spatial locations under different rainfall intensities and influence on the tailing’s mechanical properties were studied. The correlations between the parameters were analyzed by Spearman correlation analysis. The results showed that rainfall led to particle migration, with a high number of fine particles repositioning. The greater the intensity of rainfall, the more significant the migration of particles, the more obvious the changes of physical and mechanical properties of tailings. Based on Spearman correlation analysis results, it was obtained that the change of inhomogeneity coefficient of tailings has the strongest effect on cohesion, and the change of water content has the strongest effect on friction angle.

DAYA SIMPAN SERUNDENG AMPAS KELAPA SEBAGAI PRODUK PENANGGULANGAN ANEMIA GIZI BESI

Coconut pulp serundeng is a potential product with an iron (Fe) content comparable to vegetable food recommended for people with iron deficiency anemia. This study aims to determine the shelf life of coconut pulp serundeng packed with polyethylene ziplock plastic for two months. Product quality determine by analyze the number of microbes by knowing the Total Plate Number (TPN) and rancidity test by knowing the peroxide value. The results showed that no changes in physical properties were detected for aspects of color, taste, aroma, and texture during storage. The TPN test results showed that the total number of bacteria in each storage period ranges from 101 colonies/gr in accordance with the requirements listed in SNI 01-3715-2000 about dry shredded coconut (desiccated coconut). The results of the rancidity test showed that there was no detected peroxide (Peroxide Value / PV) so it could be concluded that it met the requirements listed in SNI. 3741-2013 on cooking oil. Based on the results of the study, it can be concluded that coconut pulp serundeng can be stored for up to two months using food-grade polyethylene plastic packaging with a ziplock. However, there is still a need for further research to find out, among others, the acceptability of shavings after storage, and the use of another food-grade packaging that is cheaper and more practical and extends the shelf life by more than two months

Study on Changes in Physical and Mechanical Properties and Integrity Decay of Sandstone Subjected to Freeze–Thaw Cycling

To investigate the effects of long-term freeze–thaw cycles on the physical and mechanical properties as well as the attenuation trend of rocks, this study conducted saturated freeze–thaw tests on coarse sandstone and fine sandstone samples collected from the slopes of Muli Coal Mine in Qinghai Province. The samples underwent different numbers of freeze–thaw cycles, and their porosity, longitudinal wave velocity, and uniaxial compression strength were studied. The variations in the physical and mechanical properties of the two types of sandstone with respect to the number of freeze–thaw cycles were analyzed. Take uniaxial compressive strength (UCS) as the integrity index, and decay laws of rock integrity were analyzed based on the decay equation suggested in previous studies. We found that the decay index λ, which is commonly assumed to be constant, varies with the number of freeze–thaw cycles. Furthermore, the λ values varied between different rock types. For fine sandstone, the λ decreases with an increase in the number of freeze–thaw cycles, ranging from 0.00385 to 0.005. However, for coarse sandstone, the λ initially decreases and then increases with an increase in the number of freeze–thaw cycles. The range of λ for coarse sandstone is between 0.00376 and 0.00481. Finally, we established a relationship between the decay index, porosity, and longitudinal wave velocity in the fine sandstones. This relationship provides a more straightforward way to evaluate the integrity of fine sandstones subjected to different numbers of freeze–thaw cycles.

Boost of solar water splitting on SrTiO3 by designing V-ions center for localizing defect charge to suppress deep trap

The deep trap such as Ti3+ in SrTiO3 has a great influence on its photocatalytic performance in overall water splitting, acting as a recombination center of carriers. The applied defect engineering is focused on decreasing the Ti3+ concentration for enhancing solar water splitting mainly by doping low-valence metal ions, while the high-valence metal ions are noneffective. In this work, we doped trace V ions into SrTiO3 accompanied by the Al3+ from the Al crucible, promoting the photocatalytic activity in overall water splitting based on the photocatalysis evaluation. A series of advanced techniques are used to characterize the chemical and physical property changes in SrTiO3 aroused by V ions. Combined with the density functional theory, we found that trace V ions can cooperate with Al3+ to localize the defect charge around it, suppressing the formation of deep trap and increasing the amount of potential delocalized charge at shallow state, responsible for the boost of activity. This work provides another effective method to modulate SrTiO3-based photocatalysts in defect engineering.

Evaluation of Soil Quality in Five Ages of Chinese Fir Plantations in Subtropical China Based on a Structural Equation Model

Soil quality evaluation provides necessary and fundamental data and information for understanding the current situation of the soils and for promoting the sustainable use of land resources. In this study, soil quality was assessed by developing a structural equation model (SEM) in five aged Chinese fir plantations, located in the same soil type, with similar site conditions, in Subtropical China. A total of 150 soil samples were taken from the five aged stands of Chinese fir forests: 8-year-old young forests (stand I), 14-year-old middle-aged forests (stand II), 20-year-old near-mature forests (stand III), 26-year-old mature forests (stand VI), and 33-year-old over-mature forests (stand V). Fifteen soil indicators, including soil bulk density (BD), capillary porosity (CP), total capillary porosity (TCP), water holding capacity (WHC), soil organic matter (SOM), total nitrogen (TN), available nitrogen (AN), available phosphorus (AP), available potassium (AK), soil pH, soil acid phosphatase (ACP), invertase (INV), urease (URE), and catalase (CAT), were measured. The SEM was used to determine the weight of each soil indicator, and the soil quality index (SQI) was estimated for the Chinese fir plantations. Results showed that soil physical indicators, such as BD, CP, TCP, WHC, and chemical indicators, including SOM, TN, and AN, significantly degraded in stand II groups compared with the stand I groups, but were significantly recovered in the stand III groups. However, the enzyme activity of soil biological indicators had different patterns with changes in soil physical and chemical properties. The calculated SQI in the studied Chinese fir forests ranged from 0.4084 to 0.7298, which was significantly higher in the stand V and lower in the stand II (middle-aged stand) than in the other four aged stands (p &lt; 0.05). The SEM weight analysis showed that the BD, SOM, and ACP were the most important indicators affecting the physical, chemical, and biological properties of the soils in Chinese fir forests in the study area. This study provided an innovative scientific approach for estimating the weight of SQI in forests and a theoretical basis and practical application for sustainable management of Chinese fir forest ecosystems.

Effect of annealing atmosphere on MgO thin film for tunneling magnetoresistance sensor

Magnesium oxide (MgO) thin films are the most currently used as magnetic barrier shields in tunneling Magnetoresistance (TMR) sensors. In this work, MgO (50 nm) film on silicon substrates was annealed at different temperatures (250, 350, and 450 °C) and atmospheres (Argon, Nitrogen, and air). The structure, morphology, chemical composition, and thickness were investigated by using a focused-ion beam scanning electron microscope, atomic force microscopy, and X-ray photoelectron spectroscopy techniques. Increasing annealing temperature in a normal air atmosphere increases the film's thickness and roughness due to grain growth induced by Magnesium hydroxide (Mg(OH)2) formation. On the contrary, annealing in Argon does not significantly affect the thickness and roughness of the film. Furthermore, the dielectric breakdown and hardness of the film increase. The mechanism of the change of physical properties of the film due to annealing was elucidated by a qualitative model.

Change in physicochemical properties, aroma components, and potentially beneficial compounds during the stir-frying of Massa Medicata Fermentata

Massa Medicata Fermentata (MMF) is widely applied in feed additives and human medicine. The stir-frying is a commonly used method for process of MMF, which will improve its efficacy in invigorating the spleen. However, the dynamic change of physical properties and ingredients during stir-frying remain un-elucidated. Here, the appearance color, pH values, UV–visible and fluorescence spectroscopy, content of volatile and non-volatile compounds of MMF at different process stage of stir-frying were measured. The results indicated that with increasing stir-frying time, the appearance color deepened, and pH value decreased, while the UV absorbance and fluorescence exhibited rising trends. Additionally, we identified four non-volatile compounds from MMF, and three of them showed gradual increase in content during stir-frying (from 0 to 30 min). Regarding the volatile compounds, the content of alcohols decreased, while aldehydes increased evidently after 30 min. These results demonstrated that the physicochemical properties, types of compounds and their content all significantly changed during stir-frying. The study provides insights regarding the change in substance and appearance, which will provide a guidance for the judgment of the degree of stir-frying MMF.