Rate Of Color Change Research Articles

Applicability of Multi-coating for Preserving Surfaces of Outdoor Bronze sculptures

The wax used for surface coating of outdoor bronze sculptures is prone to material aging, surface cracking, and whitening due to environmental changes and air pollutants, leading to a shortened coating treatment cycle. To improve these material limitations, I explored the possibility of applying a multi-coating method that uses both acrylic resin and wax in an outdoor environment in Korea. The results of the experiment showed that the multi-coating method significantly improved the durability of the coating layer, weather resistance against external degrading factors, corrosion prevention ability, and contact angle, etc. compared to the existing wax-only coating method, and the rate of color change (ROC) was low, proving its stability. Especially, the double-coating method of acrylic resin and wax using acrylic urethane and Bowling Alley Wax® (acrylic resin + wax) was found to be the most stable coating method among the multi-coating methods. According to such results, I found that the multi-coating method can be proposed as a new surface coating treatment method that can secure long-term preservation of bronze sculptures and preserve their original form even in outdoor environments in Korea, by remedying the shortcomings of the wax-only coating.

Utilization of beef lung powder in model chicken emulsion formulation

AbstractThe present study aimed to demonstrate the effect of beef lung powder addition to model chicken emulsion formulations on quality parameters and determine the optimum usage dose. A mixture design method was employed to determine the ideal proportions of chicken meat, animal fat, and water. The optimal formulation comprises 70.48% chicken meat, 12.42% animal fat, 9.30% water/ice, and 7.80% beef lung powder (w/w). The predicted outcomes for this optimized emulsion include a cooking loss of 3.05%, emulsion stability of 85.21%, an oxidation rate increase of 2.93%, a color difference of 13.24%, and firmness of 24.16 N. The use of lung powder resulted in a reduction in cooking loss and an increase in emulsion stability and hardness. Nevertheless, an increase in both color change and oxidation rate was found in emulsion models. The results of this study demonstrate that beef lung powder is a highly functional ingredient with the capacity to significantly enhance the stability and texture of chicken emulsions. Furthermore, it has the potential to considerably improve the nutritional and quality attributes of emulsified meat products, therefore suggesting its broader applicability in food production.

Composite Coatings of Gellan Gum and Inulin with Lactobacillus casei: Enhancing the Post-Harvest Quality of Guava

Guava is a highly sought-after tropical fruit in the market due to its high content of vitamins, minerals, antioxidants, and other phenolic compounds. However, due to its climacteric nature, it has a short post-harvest shelf life. The aim of this study was to develop coatings based on gellan gum (GG) and inulin (IN) incorporating Lactobacillus casei, which were tested for their potential ability to extend the post-harvest shelf life of whole guava fruit. The coatings were prepared using the following formulations: 0.5 GG/1.0 IN (w/v), 0.8 GG/5.0 IN (w/v), 0.5 GG/1.0 IN(w/v), and 0.8 GG/5.0 IN (w/v). The coated and uncoated (control) fruits were stored at 25 °C for 12 days, and various quality attributes were evaluated (including respiration rate, soluble solids, titratable acidity, weight loss, total phenol content, and color). The results indicated that the application of the coatings reduced weight loss, color change, and respiration rate in the fruits. However, the 0.8 GG/5.0 IN (w/v) formulation provided the best maintenance of post-harvest quality for the fruit evaluated. The coatings with a higher inulin content showed the highest growth of L. casei, which could enhance the antimicrobial effect of the coating. Therefore, the combined application of L. casei and inulin in coatings based on gellan gum can be considered an effective treatment to extend the shelf life and preserve the quality of guava fruits.

In Vitro Kinetic and Thermodynamic Staining Study of Three Energy Drinks on the Restorative Charisma Composite

Abstract Aim: The research utilized charisma composite resin, a dental restorative material known for its esthetic properties, with the chemical formula 2,2-bis[p(2-hydroxy-3-methacryloxy propoxyphenyl)] propane. The primary objective of the study was to examine the overall color change (ΔE*ab) of the charisma resin after it was subjected to three distinct energy drink solutions: Monster Energy Ultra-Sunrise, Wild Tiger, and Red Bull. Further we examined the effects of temperature and time on the staining interaction and overall color difference ΔE*ab on the surface of charisma restorative resin generated by three energy drink. Materials and Methods: A microfilled Charisma Classic composite resin was used in presented comparative study selected. The prepared 144 composite disk samples (subdivided n=48) with random allocation method were used for the three energy drinks to determine the effect of temperature and time over the course of 90 days. A metallic circulator mold was prepared. Every set of 48 specimens in the energy drink was heated in a water bath for 1, 7, 30, 60, and 90 days at four different temperatures This investigation spanned various time intervals, ranging from 1 to 90 days, and encompassed four temperature levels between 283 and 310 K. One-way ANOVA was used to evaluate the mean data for color change between the energy drinks, and Tukey’s post hoc test was used for multiple comparisons, with a significance level of P < 0.05. Results: The study revealed that the rate of staining was most pronounced in the case of Wild Tiger, while it was comparatively lower for Monster Energy Ultra-Sunrise. These findings were established through an examination of the kinetic and thermodynamic behavior of surface color changes in micro-hybrid composites treated with the three energy drink solutions. Conclusions: The observed patterns aligned with the pseudo second-order model. It was observed that the Red Bull drink displayed a negative activation energy, resulting in a slower color change rate with increase in temperature. In contrast, endothermic, spontaneous, and regular staining activity was demonstrated throughout time by Monster Energy Ultra-Sunrise and Wild Tiger.

Characterization of WO3/Silicone Rubber Composites for Hydrogen-Sensitive Gasochromic Application.

WO3 and silicone rubber (SR)-based gasochromic composites were fabricated to detect hydrogen leaks at room temperature. WO3 rod-like nanostructures were uniformly distributed in the SR matrix, with a particle size of 60-100 nm. The hydrogen permeability of these composites reached 1.77 cm3·cm/cm2·s·cmHg. At a 10% hydrogen concentration, the visible light reflectance of the composite decreased 49% during about 40 s, with a color change rate of 6.4% s-1. Moreover, the composite detected hydrogen concentrations as low as 0.1%. And a color scale was obtained for easily assessing hydrogen concentrations in the environment based on the color of composites. Finally, the composite materials as disposable sensors underwent testing at several Sinopec hydrogen refueling stations.

A prognostic and health management approach using colour fade to determine the condition of silk in a museum display environment

Silk is highly susceptible to fade, often resulting in colour loss to the fabric even when displayed in controlled museum environments. This study applies the engineering-inspired Prognostics and Health Management (PHM) approach to assess the remaining useful life (RUL) of silk fabric in a museum environment, focussing on predicting colour fade as an indicator of degradation. A novel mathematical model is developed to forecast cumulative colour fade of silk upholstery exhibited at the Great Gallery in The Wallace Collection, London. Unlike traditional accelerated aging methods, this model utilises naturally aged samples to estimate the rate of colour change over time. The main contribution of this work lies in the methodology and computational framework for model development using environmental data and conditions of silk in the museum environment. The proposed PHM methodology allows for continuous modifications of the colour fade model to improve accuracy by deploying new data from different silk collections and environments. The article demonstrates a model-based approach for informed decision making in museums regarding display and storage of silk upholstery.

Photorewriting, Time-Resolved Encryption, and Unclonable Anticounterfeiting with Artificial Intelligence Authentication via a Reversible Photoswitchable System.

In the fields of photolithographic patterning, optical anticounterfeiting, and information encryption, reversible photochromic materials with solid-state fluorescence are emerging as a potential class of systems. A design strategy for reversible photochromic materials has been proposed and synthesized through the introduction of photoactive thiophene groups into the molecular backbone of aryl vinyls, compounds with unique aggregation-induced emission properties, and solid-state reversible photocontrollable fluorescence and color-changing properties. This work develops novel photochromic inks, films, and cellulose hydrogels for enhancing the security of information encryption and anticounterfeiting technologies. They achieve rapid and reversible color change under ultraviolet light irradiation. Dependent upon the rate of color change, higher levels of time-resolved security can be achieved. This feature is important for enhancing the confidentiality of encrypted information and the reliability of security labels. Color-changing cellulose hydrogels, inks, and films consisting of three photochromic fluorescent molecules have quick photoactivity, great photoreversibility and photostability, and good processability, making them ideal for time-delayed anticounterfeiting and smart encryption. Furthermore, specialized algorithms are used to construct convolutional neural networks, and image analysis is performed on these systems, thus solving the current problem of the time-consuming information decryption process. This artificial intelligence method offers new opportunities for enhanced data encryption.

Effect of Maturity Stages on the Quality of Cold Storage Iceberg Lettuce (Lactuca sativa var. capitate) for Export

Iceberg lettuce is one of the most important vegetables economically and nutritionally, but its perishable nature poses challenges for storage and long-distance transportation. This study investigated the effect of maturity stages on the quality of iceberg lettuce for export under cold storage conditions. A completely randomized design with three replications was used to evaluate four maturity stages based on days after planting (DAP): 52, 55, 58, and 61 DAP. The lettuce heads were stored at 3±2oC and a 95% relative humidity, and quality parameters were analyzed every three days until the end of storage. Sensory properties, weight loss, color change, total soluble solids, total phenolics, and decay rates were evaluated. The results showed that maturity stages significantly (P <0.05) affected the quality attributes of iceberg lettuce and that harvesting at the optimal stage is very important. Findings from this study confirmed that the quality parameters were preserved for the 58 DAP samples throughout the storage time. They indicated that at three weeks of storage time, the lowest weight loss (5.9%), color change (14.1), and decay rate (8.3%), and the highest sensory analysis (5 scores) and appearance were shown by the 58 DAP maturity stage lettuce. Therefore, harvesting iceberg lettuce at 58 DAP is recommended for long-distance exportation.

Air-frying of meat analog based parfried frozen batter coated foods

Air-frying (AF) is a novel method of producing low-fat containing fried foods using hot-air. This study investigated the effects of AF parameters on mass-transfer, texture, surface microstructure and color changes during air frying of meat-analog based batter coated parfried frozen products, and mathematically modeled their kinetics. Wheat and rice flour-based batters were used to coat a meat-analog model. Coated products were partially-fried at 180 °C for 1 min in canola oil and subsequently frozen at −18 °C for 7 days. Frozen-products were fried for different time (0, 5, 10, 15, 20 min) by hot-air of different temperature (160, 170, 180, 190 °C). Mass-transfer, texture and color development during AF of parfried-frozen coated products were dependent on both AF parameter and batter-formulations. At varied temperature, moisture content of frozen-products declined with AF time. Non-linear regression analysis outcome (R2, sum square error) showed that Newton, Page, modified Page, and Henderson & Pabis model satisfactorily predicted moisture-loss of parfried-frozen products. Zero-order kinetic model satisfactorily characterized the changes in textural (hardness, brittleness, crispiness) and color (L, a*,b*, ΔE) traits. Rate-constant (min−1) of moisture, texture and color changes were positively correlated with AF temperature. Arrhenius model sufficiently characterized the temperature-dependency of rate constants. Higher moisture diffusivity (Deff, m2/min) and rate constant (k, min−1) of textural changes were estimated for rice-flour based batter coated products, whereas higher rate of total color change (ΔE) and activation energy (Ea, kJ/mol) were estimated for wheat-flour based batter coated products. Surface microstructure (openings, roughness) of air-fried products were impacted by batter-formulation and parameters of AF. Overall, batter formulations and AF parameters are the key to customize both macro and micro quality attributes of meat-analog based batter coated product.

Light-specific wavelengths differentially affect the exploration rate, opercular beat, skin color change, opsin transcripts, and the oxi-redox system of the longsnout seahorse Hippocampus reidi

Light is a strong stimulus for the sensory and endocrine systems. The opsins constitute a large family of proteins that can respond to specific light wavelengths. Hippocampus reidi is a near-threatened seahorse that has a diverse color pattern and sexual dimorphism. Over the years, H. reidi's unique characteristics, coupled with its high demand and over-exploitation for the aquarium trade, have raised concerns about its conservation, primarily due to their significant impact on wild populations. Here, we characterized chromatophore types in juvenile and adult H. reidi in captivity, and the effects of specific light wavelengths with the same irradiance (1.20 mW/cm2) on color change, growth, and survival rate. The xanthophores and melanophores were the major components of H. reidi pigmentation with differences in density and distribution between life stages and sexes. In the eye and skin of juveniles, the yellow (585 nm) wavelength induced a substantial increase in melanin levels compared to the individuals kept under white light (WL), blue (442 nm), or red (650 nm) wavelengths. In addition, blue and yellow wavelengths led to a higher juvenile mortality rate in comparison to the other treatments. Adult seahorses showed a rhythmic color change over 24 h, the highest reflectance values were obtained in the light phase, representing a daytime skin lightening for individuals under WL, blue and yellow wavelength, with changes in the acrophase. The yellow wavelength was more effective on juvenile seahorse pigmentation, while the blue wavelength exerted a stronger effect on the regulation of adult physiological color change. Dramatic changes in the opsin mRNA levels were life stage-dependent, which may infer ontogenetic opsin functions throughout seahorses' development. Exposure to specific wavelengths differentially affected the opsins mRNA levels in the skin and eyes of juveniles. In the juveniles, skin transcripts of visual (rh1, rh2, and lws) and non-visual opsins (opn3 and opn4x) were higher in individuals under yellow light. While in the juvenile's eyes, only rh1 and rh2 had increased transcripts influenced by yellow light; the lws and opn3 mRNA levels were higher in juveniles' eyes under WL. Prolonged exposure to yellow wavelength stimulates a robust increase in the antioxidant enzymes sod1 and sod2 mRNA levels. Our findings indicate that changes in the visible light spectrum alter physiological processes at different stages of life in H. reidi and may serve as the basis for a broader discussion about the implications of artificial light for aquatic species in captivity.

Tracking photosynthetic phenology using spectral indices at the leaf and canopy scales in temperate evergreen and deciduous trees

Vegetation photosynthetic phenology is an important indicator to characterize the biological responses of terrestrial carbon cycle to climate change. Remote sensing-derived spectral indices have been used to estimate photosynthetic phenology of terrestrial ecosystems, yet there are large uncertainties due to differences in leaf structure and canopy function between evergreen and deciduous trees. In this study, we used in-situ measured meteorology, the maximum rate of leaf-level CO2 assimilation (Amax), chlorophyll fluorescence and canopy color changes in evergreen and deciduous species to evaluate and compare the abilities of spectral indices for photosynthetic phenology modeling. Seasonal variation in Amax is used as a proxy for photosynthetic phenology. Several indices were used, including the normalized difference vegetation index (NDVI), near-infrared reflectance vegetation index (NIRv), photochemical reflectance index (PRI), chlorophyll/carotenoid index (CCI), green-red vegetation index (GRVI), and green chromaticity coordinates (Gcc). We found that NIRv and PRI estimated phenological periods for Cedrus deodara and three deciduous trees all differed from Amax by less than 5 days, and all were linearly related to Amax (R2 > 0.6). CCI had less potential for Amax modeling, while NDVI had the largest error in predicting Amax. Gcc was a more accurate proxy for photosynthetic phenology than GRVI at the canopy scale. In addition, we found that the variability of different spectral indices in tracking photosynthetic phenology of evergreen and deciduous species was related to non-photochemical quenching processes. Especially for the fraction of absorbed light quenched by dynamic NPQ (ɸNPQ) and the fraction of absorbed light quenched by sustained NPQ (ɸf,D), they contribute more than 40 % to the variations of the NIRv and PRI spectral signals. Therefore, NIRv and PRI provide powerful tools for monitoring photosynthetic phenology, and future exploration of NIRv and PRI at larger spatial scales will favor the global plant phenology and carbon uptake modeling.

Losses of sexual dichromatism involve rapid changes in female plumage colors to match males in New World blackbirds.

Differences in coloration between the sexes (sexual dichromatism) can increase or decrease in a species through evolutionary changes in either or both sexes diverging or converging in their colors. Few previous studies, however, have examined the relative rates of such changes, particularly when dichromatism is lost. Using reflectance data from 37 species of the New World blackbird family (Icteridae), we compared evolutionary rates of plumage color change in males and females when dichromatism was either increasing (colors diverging) or decreasing (colors converging). Increases in dichromatism involved divergent changes in both sexes at approximately equal rates. Decreases in dichromatism, in contrast, involved changes in females to match male plumage colors that were significantly more rapid than any changes in males. Such dramatic changes in females show how selection can differ between the sexes. Moreover, these evolutionary patterns support the idea that losses of dimorphism involve genetic mechanisms that are already largely present in both sexes, whereas increases in dimorphism tend to involve the appearance of novel sex-specific traits, which evolve more slowly. Our results have broad implications for how sexual dimorphisms evolve.

An approach of shelf-life extension technology focusing on recovery lug of physiological responses: Kinetic analysis for residual effect of modified atmosphere packaging on the color changes of broccoli flower buds

Physiological activity of vegetables can be changed by postharvest technology, and the recovering of the response may have time lug, as a residual effect on them. This study investigated an approach of shelf-life extension technology using the residual effect on broccoli with modified atmosphere packaging (MAP). Color changes in broccoli flower buds indicate a decline in their quality and such changes can be avoided through respiration control via MAP. This study determined the residual effects of MAP on the color changes during a 9-day storage at 10 °С. The interval period of MAP varied on days 2, 5, 7, and 9 in early stage. Interestingly, the residual effects of MAP after the package release could be confirmed if the colors compared to the control samples were not different at the release point. The residual effects significantly reduced the color change rate to < 50%, and the effect degrees were dynamically changed during the subsequent storage. This study assumed that the residual effects could delay the physiological response recovery. Therefore, the time lug of physiological response recovery changed by MAP may use as an approach of shelf-life extension technology of broccoli, especially for food waste reduce in supply chain.

Exploration of effects by the ‘alum-glue solution’ on Xuan paper degradation using a 23 factorial design experiment

In the traditional Chinese conservation mounting process, it is well acknowledged that the alum-glue solution, composed of potassium aluminum sulfate [KAl(SO4)2·12H2O], gelatin, and water, is commonly used for paper sizing. In this study, its adverse effects when prepared in different ratios on the contemporary Xuan paper are explored, demonstrating certain negative influences on material properties and paper durability. We primarily characterized an extra-pure Xuan paper as a reference sample. Then, a 23 full factorial experiment was designed and performed to explore the effects of the three factors, i.e., KAl(SO4)2·12H2O (denoted as alum), animal glue or gelatin (denoted as glue), and water contents on rates of paper degradation [kΔ(1/DP)] and color changes (kΔL and kΔb). The results show that the unsized extra-pure Xuan paper sample has good stability due to appreciable alkaline reserve, weakly alkalinity, and no presence of transition metals. Fourier transform infrared (FTIR) spectra and scanning electron microscope (SEM) images demonstrate the presence of sizing. Given that the alum-glue solution has been widely used in paper conservation, the results in this study demonstrate the devastating role of KAl(SO4)2·12H2O and the protective effects of gelatin on durability of treated papers, verified by the DP-related data. Additionally, it was found that the presence of alum is mainly responsible for the lightness decrease of the treated papers, and animal glue plays a primary role in paper yellowing. The findings in this research can deepen our understanding of the rate of paper degradation and color changes for the Xuan paper treated with the alum-glue solution.

Изменение физико-химических и органолептических характеристик яблочного пюре при повышенных температурах хранения

Food products change their quality during storage not only under the external impact, but also because they are complex in composition. As a result, food scientists look for new methods to control these internal changes. The research objective was to describe the changes in the physicochemical properties of apple puree during storage at elevated temperatures (40–60°C) and link them with the changes in the sensory profile.&#x0D; The study featured homogenized apple puree packaged in composite material and heated up to 40, 50, and 60°C. The colorimetric studies were conducted at 45°/0°, light source D65. The proton relaxation time and the water diffusion coefficient (impulse gradient method) were studied at a frequency of 20 MHz. The analysis of molecular dynamics involved the method of electron paramagnetic resonance of spin probes. The samples were cooled down to –70°C to measure the content of non-crystallizing water by the method of differential scanning calorimetry.&#x0D; The color change rate was constant and followed the zero-order kinetic reaction equation with an activation energy of 92 kJ/mol. The changes in color, proton relaxation, and sensory properties correlated when the samples were stored at 50 and 60°C. The analysis of the magnetic relaxation time, the diffusion coefficient of water, and the content of non-crystallizing water indicated that the main changes in the physical structure of the puree during heat treatment occurred as a result of the aggregation of apple cell fragments. These findings were confirmed by the optical microscopy.&#x0D; A prolonged exposure to 40–60°C affected the color, the relaxation of water protons, and the size of aggregates of apple cell fragments. It also affected the amount of water that did not crystallize at –70°C. The correspondence between the values of the activation energies was determined by the methods of colorimetry and proton relaxation. Therefore, the coloration and the water changes depended on the same processes. These physical and chemical properties can be used for quantitative assessment of apple puree under thermal treatment.

Effect of Different Concentrations of 1-MCP and Varied Storage Environments on Physical Characteristics and Consumer Acceptability of Solo Papaya (Carica papaya L.) Fruits

The nature of papaya fruits is intently connected with their physical characteristics. Changes during aging are critical, yet uncontrolled ripening procedure can prompt fast degradation of quality. Despite the myriads of problems during storage and transportation or distribution, it is imperative to control ripening so as to reduce losses and maximize profit. A 4x2 factorial experiment in a completely randomized design was carried out to determine the effects of applying four concentrations of 1-MCP under two storage conditions on physical characteristics and consumer acceptability of ‘Solo’ papaya. During ripening, data on various physical characteristics including fruit firmness, cumulative weight loss (%), fruit skin color, shelf life and consumer acceptability were monitored. The 1-MCP treated fruit retained their firmness better than the control (untreated) fruit, regardless of whether they were stored under ambient or cold storage conditions. The percentage of weight loss decreased with increasing 1-MCP concentrations. In general, the 1-MCP treated fruit revealed a slower rate of color change compared to the control. The shelf-life of the papaya fruit treated with 1.5 ppm of 1-MCP and stored under ambient storage condition was extended by approximately 2 days. However, at the same concentration (1.5ppm) of 1-MCP but under cold storage condition, shelf life was extended by approximately 3 days.

Bamboo lumber – an innovative sustainable raw material and an accelerated weathering study for establishing its durability

Bamboo lumber was prepared using Bambusa bamboos species and its weathering performance was evaluated under natural and accelerated weathering. Specimens of bamboo lumber were exposed to natural weathering for 150 days. Another set of specimens were exposed to UV light source (UVA 360) in accelerated weathering tester up to 250 hours. A comparative study on the level of degradation in natural and accelerated weathering was made by evaluating CIEL*a*b* colour changes measured using a Hunter lab spectro-colorimeter. Rate of color change due to photo-degradation were evaluated. Results showed that all three color axes, viz. lightness (L*), redness (a*) and yellowness (b*) changed linearly with respect to time under natural exposure, but only L* was changed under accelerated weathering, keeping a* and b* values to be almost constant. Photodegradation of bamboo was mainly due to UV light absorption by chromophores present in the lignin, which constitutes about 32,2 % of total bamboo.

Realizing sensations: analyzing Paul Cezanne’s watercolors and assessing their light sensitivity with microfade testing

The exhibition Cézanne Drawing at The Museum of Modern Art (MoMA) brought together an exceptional group of works on paper from public and private collections across the globe. Recognizing the inherent light sensitivity of both the paper and watercolors, controlling, and tracking light exposure was central to the exhibition planning. This concern also led to a systematic study of three watercolors in the museum’s collection, Foliage (1895), Study of Trees (1895), and Mont Sainte-Victoire (1902-06), to characterize the watercolor paints used by Cezanne in these works and their sensitivity to light exposure, and to better understand the condition of the drawings based on the palette’s chemistry. Examination and analysis were undertaken non-invasively and micro-invasively with the following techniques: Infrared Reflectography (IRR), Ultraviolet Fluorescence Photography (UVF), Raman and surface-enhanced Raman (SERS) spectroscopies in addition to X-Ray fluorescence analysis on small spots and large areas using portable (p-XRF) and XRF scanning, respectively. The palette for these three watercolor drawings includes lead white, bone black, vermilion, yellow ochre, chrome yellow, emerald green, viridian, cobalt blue, and synthetic alizarin and carmine lakes. Microfade testing (MFT) was performed on the paper support and spots with each identified pigment, and the data acquired was evaluated both for color change (ΔE00) and rate of color change (frac{partial Delta {E}_{00}}{partial t}). Together these techniques inform the future display and loan of these and similarly fugitive watercolors in Cézanne’s oeuvre.

Ultrasound‐assisted hot air drying characteristics of Phyllanthus emblica

AbstractThe ultrasound‐assisted hot air drying characteristics of Phyllanthus emblica was investigated in this paper. The effects of hot air temperature (60°C, 65°C, 70°C, and 75°C), ultrasonic pretreatment time (2, 4, 6, and 8 min), and ultrasonic power (200, 250, 300, and 350 W) on the drying rate, energy consumption, color change, and rehydration rate were evaluated and compared. It was found that the drying rate of Phyllanthus emblica increased with the hot air temperature. The drying time of Phyllanthus emblica with ultrasonic pretreatment was reduced by 10.0%, 25.0%, 21.4%, and 9.0% at 60°C, 65°C, 70°C, and 75°C, respectively. However, the hot air drying was not proportionally promoted by the increase of ultrasonic power or the extension of pretreatment time. Only an appropriate ultrasonic power or pretreatment time can not only improve the drying rate and rehydration rate, but also reduce the energy consumption and the total color change of the dried samples. A new drying model that considered the influences of hot air temperature, pretreatment time, and ultrasonic power was developed to fit the drying process. The results showed that the new model can accurately predict the hot air drying process of Phyllanthus emblica with and without ultrasonic pretreatment.Practical applicationsPhyllanthus emblica contains a variety of nutrients and has various biological activities. However, the harvest period and shelf life of Phyllanthus emblica is very short, and the fruit is prone to mildrew and browning after picking, which in turn leads to the loss of its nutritional and economical value. Thus, for the long‐term preservation of Phyllanthus emblica, drying techniques are needed. In the food industry, hot air drying is widely used due to its low cost and easy operation; however, it also has some disadvantages such as long drying time, the oxygen‐rich drying environment. These shortcomings lead to a low quality of dried materials. Ultrasonic pretreatment before hot air drying can improve drying efficiency without adversely affecting the drying quality of the material. In recent years, ultrasonic pretreatment before food drying has become a research hotspot.

The Effect of a Setting Accelerator on the Physical and Mechanical Properties of a Fast-set White Portland Cement Mixed with Nano-zirconium Oxide.

This study compared the effects of calcium chloride dihydrate (CaCl2.2H2O) on the physical properties and push-out bond strength of white Mineral Trioxide Aggregate (WMTA) and an experimental Malaysian Portland cement mixed with nano-zirconium oxide (nano-ZrO) [(radiopaque Malaysian Portland cement (RMPC). Mineral Trioxide Aggregate (MTA) was the first calcium silicate cement (CSC) introduced in dentistry, but up to date, it is an expensive cement with long setting time and causes tooth discolouration. Although Portland cement has been introduced as a potential substitute to MTA, it still faces some challenges such as long setting time and lack of sufficient radiopacity. Four groups [WMTA, RMPC, fast-set WMTA (FS-WMTA) and fast-set RMPC (FS-RMPC)] were prepared. Initial setting time was evaluated using Vicat apparatus. The pH was measured at seven-day intervals. For discolouration potential, cements were packed in the pulp chamber of 46 extracted maxillary incisors. Spectrophotometric readings were obtained at seven-day intervals, and the rate of colour change (ΔE) was recorded. For the push-out bond strength testing, cements were applied in 48 sectioned root samples, and the test was performed using universal testing machine at crosshead speed of 0.5 mm/min until bond failure. Statistical analysis was done according to the nature of each group of data using SPSS 26. Addition of CaCl2.2H2O decreased the initial setting times of both RMPC and WMTA significantly (p<0.05). The pH values of FS-WMTA and FS-RMPC were comparable to their non-accelerated counterparts ranging from 10 to 12. Discolouration effect was more obviously observed with WMTA and FS-WMTA with time compared to RMPC formulations. Push-out bond strength of the two materials also showed an increase with the addition of the accelerator, however, only FS-WMTA showed statistically significant difference compared to WMTA (p<0.05). The addition of CaCl2.2H2O improves the physical and mechanical properties of the newly formulated RMPC and WMTA. The RMPC formulation overcomes the discolouration potential of WMTA. (EEJ-2022-12-155).