Chromatic Parameters Research Articles

Self‐reduction triggered color tuning of Eu3+‐doped aluminosilicate glass for solid‐state white illumination

AbstractRare earth‐doped transparent glass, boasting high transmittance and excellent luminescent properties, holds great potential in the field of all‐inorganic solid‐state white illumination. Currently reported single‐structure solid‐state white lighting usually has the problems of low color rendering index (CRI) and high correlated color temperature (CCT) due to the lacking of red light emission. In this work, a novel single‐structure MgO–Al2O3–SiO2–Eu2O3 (MAS: Eu) glass with color tuning was prepared by the simple glass melting process. Interestingly, the prepared Eu3+‐doped aluminosilicate glass possessed a unique capability to achieve color emission under different excitation wavelengths. The reason for this was attributed to the good self‐reduction capability of the MAS glass, which effectively reduced Eu3+ to Eu2+ under an air atmosphere. Meanwhile, only by regulating the Eu3+ doping concentration, the MAS glass also achieved a tunable emission from blue to white to red light under 380 nm excitation. The acquisition of white light was realized through the multispectral emission of blue–green light emitted by Eu2+ and orange–red light emitted by Eu3+. Remarkably, the single‐structure MAS glass doped with 8 wt.% Eu3+ successfully achieved high‐quality white light and high thermal stability, exhibiting a high CRI of 86, a low CCT of 2761 K, good chromaticity parameters of (0.407 and 0.3192), and the emission intensity at 423 K remains above 86.35% that of room temperature. Meanwhile, the doped Eu3+ exceeded 12 wt.%, without any observable concentration quenching. Moreover, the MAS: Eu glass showed a high transmittance of 90 and a moderate thermal conductivity of 1.45 W/mK (epoxy resin ∼0.17 W/mK). These results would dramatically inspire the development of high‐quality solid‐state white lighting applications.

Modeling the Color Characteristics of Sapphires through the Statistical Method and Function Simulation Method

The aim of this study was to explore the feasibility of quantitatively evaluating a sapphire’s color by analyzing gemstone images. The color characteristics of gemstones through photography and color extraction were accurately captured, and the key color parameters for different color regions of gemstones were extracted. Then, the color of sapphires was simulated by statistical method and function simulation method. The results indicate that the brightness value of the bright area was the highest and the chroma value of the “fire” area was the highest. The chroma (C) of the sapphires was linearly positively correlated with the absolute value of its b value, and the brightness (L) showed a quadratic correlation with its chromaticity parameters (b or C). The function simulation method with an average of b as the main independent variable had a larger standard deviation, which proves that this method has a stronger ability to distinguish the differences in a sapphire’s color. This method can be extended to the color evaluation of other colored gemstones, and it can be used to form a gemstone color evaluation system.

Optimizing Sweet Cherry Attributes through Magnesium and Potassium Fertilization

Plant nutrition through fertilizer application plays a crucial role in enhancing crop quality and yield, necessitating a balanced fertilization approach. Sweet cherry, esteemed as one of the most prized crops worldwide, was the focus of this three-year study spanning from 2019 to 2021, involving the sweet cherry cultivar Burlat. This study investigated the foliar application of magnesium (Mg) and potassium (K) to enhance fruit quality parameters. Different doses of Mg (250 g hL−1 and 125 g hL−1) and K (100 g hL−1 and 50 g hL−1) and a control treatment were administered to sweet cherry trees to assess their impact on fruit quality. At the commercial ripening stage, fruits from each treatment were harvested for comprehensive evaluation, including biometric and chromatic parameters, fruit firmness, routine parameters, sensory profile, and nutrient content analysis. Results from the study revealed notable enhancements in fruit weight and dimensions, particularly in the control treatment in 2020. Furthermore, Mg125 and Mg250 treatments exhibited improved color development and accelerated maturity by increasing the total soluble solids content while decreasing titratable acidity. Sensorial profiling indicated that Mg125 and Mg250 treatments intensified color intensity and sweet taste while mitigating sour taste perceptions. Conversely, potassium fertilization, especially the K50 treatment, led to increased fruit firmness and nutrient content. These findings offer valuable insights into optimizing sweet cherry production practices globally.

Correlation of chemical composition and sensory scores in Spanish Monastrell red wines: Insights from a blind wine competition

Red wine is a complex beverage, both chemically and sensorially, making it a very interesting beverage from a sensory perspective. Additionally, wine offers consumers a multitude of choices and brands. Considering this diversity, wine competitions and scoring could provide a way of helping consumers in their choices. In this study, sixty-seven commercial Spanish Monastrell red wines, which participated in an official blind contest, were grouped into different winemaking categories based on aging and wood contact. These wines were chemically analyzed to explore relationships between their allocated groups and their chemical composition. Additionally, the study aimed to find correlations between the total scores given in the contest and the wines' volatile compounds, chromatic parameters, and physicochemical properties. The goal was also to identify the chemical parameters that most strongly correlated with the obtained scores. Considering all 67 wines, the results showed a significant linear regression between the wine scores and their physicochemical and volatile compounds, with a coefficient of determination of 48.4 %. However, when the wines were analyzed considering the different categories, the coefficient of determination for those wines competing in the category of aged wines increased up to 84.8 %. In addition, some wine chromatic characteristics such as color intensity, total phenol index and polymeric anthocyanin seemed to be highly related to the score received for the wines in a contest. Therefore, the results obtained in this work can be useful to define a certain style of wine that most probably could get a higher score in a wine contest.

The photoluminescence studies of Gd3+/Tb3+ co-doped xerogels and nano-glass-ceramics dedicated for green-emitting devices

In this work, we reported the results of photoluminescent and structural investigations of Gd3+/Tb3+ co-doped silicate xerogels as well as derivative SiO2-LaF3 nano-glass-ceramics. The molar ratio of appropriate acetates used during the synthesis, i.e., La(AcO)3:Gd(AcO)3:Tb(AcO)3 was fixed to x:(0.95-x):0.05. Based on XRD measurements, the crystallization of hexagonal LaF3 nanophase was verified without any admixture of GdF3 phase, even for samples with La3+:Gd3+ molar ratio ≤1. The optical characterization of fabricated Gd3+/Tb3+ co-doped sol-gel materials involved the registration and analysis of photoluminescence excitation (PLE) and emission spectra (PL), as well as the decay curves for the 6P7/2 (Gd3+) and the 5D4 (Tb3+) excited levels. Upon excitation at λex = 275 nm wavelength, the fabricated sol-gel samples revealed the series of emission lines assigned to the electronic transitions from both dopants, i.e., Gd3+ and Tb3+, indicating apparently the occurrence of Gd3+/Tb3+ energy transfer process (ET). The photoluminescence measurements comprehensibly proved the competitiveness between Gd3+ and Tb3+ ions to be entered into LaF3 fluoride nanocrystal lattice, formed during annealing of as-prepared xerogels. Based on the recorded PL spectra for fabricated sol-gel samples, some chromatic parameters were calculated, i.e., chromaticity coordinates (CIE), correlated color temperatures (CCT), and color purities (CP). The prepared Gd3+,Tb3+ co-doped samples are able to emit green light with CCT values in a range from 5967 K to 6291 K, and high CP reached 70 %, which predispose them for use as efficient constituents for developing green-emitting devices.

Development of a Freshness Indicator for Assessing the Quality of Packaged Pork Products during Refrigerated Storage.

A pH-sensitive dye-based freshness indicator has been developed to monitor the quality status of pork neck through distinct color transitions, addressing a crucial need for improved food safety and real-time monitoring within the food industry. This system aims to boost consumer confidence and improve shelf-life estimates by offering transparent and immediate quality indicators. Aerobically packaged pork neck samples underwent accelerated testing at 25 °C for 36 h, followed by refrigeration experiments at typical distribution temperatures of 4 and 8 °C over 10 days. Measured pork neck quality parameters included total bacterial count (TBC), total volatile basic nitrogen (TVB-N), and pH levels. Visual observation and colorimetric analysis were used to assess the chromatic variations of the freshness indicator, which showed a significant shift from orange to green in response to the presence of TVB-N in the headspace of the pork packaging. The chromatic parameters of the freshness indicator exhibited a significant correlation with the pork quality values throughout the storage periods. The results highlight the ability of the freshness indicator to effectively convey quality information about pork through noticeable colorimetric changes.

On Strong Regal and Strong Royal Colorings

Two colorings have been introduced recently where an unrestricted coloring c assigns nonempty subsets of [ k ] = { 1 , … , k } to the edges of a (connected) graph G and gives rise to a vertex-distinguishing vertex coloring by means of set operations. If each vertex color is obtained from the union of the incident edge colors, then c is referred to as a strong royal coloring. If each vertex color is obtained from the intersection of the incident edge colors, then c is referred to as a strong regal coloring. The minimum values of k for which a graph G has such colorings are referred to as the strong royal index of G and the strong regal index of G respectively. If the induced vertex coloring is neighbor distinguishing, then we refer to such edge colorings as royal and regal colorings. The royal chromatic number of a graph involves minimizing the number of vertex colors in an induced vertex coloring obtained from a royal coloring. In this paper, we provide new results related to these two coloring concepts and establish a connection between the corresponding chromatic parameters. In addition, we establish the royal chromatic number for paths and cycles.

P‐114: A Method for Visualizing and Quantifying Color Differences using Relative Hue and Relative Color Concentration and its Application

This paper innovates a method for visualizing and quantifying color differences using relative hue and relative color concentration. Firstly, the relative hue and relative color concentration are proposed to solve the problem that conventional chromaticity parameters can't characterize color difference. Secondly, the color difference visualization and quantification method realized by weighting algorithm and VB programming can replace the conventional qualitative assessment by human eyes, which greatly improves the accuracy and repeatability. Finally, this paper takes the color difference problem of 2 a‐Si products as an example, and uses the method of this paper to test and analyze, and easily clarifies the cause of color difference as the uneven thickness of Panel SINx film layer and the slow settling rate of LED phosphor. Combined with principle analysis, optical simulation, and experimental verification, this paper finally proposes an improvement plan to solve the stubborn color difference problem of a‐Si products.

STUDY OF THE INFLUENCE OF CONSERVATION TREATMENT ON THE CHROMATIC CHARACTERISTICS OF ARABIC MANUSCRIPTS

In the present experiment, a study was conducted to investigate the effect of conservation treatment of an Arabic manuscript on its chromatic characteristics. For this purpose, extremely valuable, unrestored manuscripts (18 - 19th century) were selected from the archives of the National Library “St. St. Cyril and Methodius”, on which spectrophotometric chromatic characteristics were measured. The research was conducted at the restoration center of the National Library. The following processes were applied to the manuscript: mechanical cleaning anddeacidification. Measurements of color characteristics were taken indifferent parts of the manuscript after each stage of the treatment: before treatment, after mechanical cleaning, after deacidification. The following parameters - CIE Lab, CIE Lch, ∆Eab, ∆E2000, ∆L, ∆c, ∆h was calculated. Based on the results obtained, the changes and effects of each of the chromatic parameters were determined.

Precipitation synthesis of Zn2-xCoxSiO4 blue ceramic pigments: Color performance and application

A simplified precipitation route based on using silica hydrogel derived from serpentine minerals as a source of silica SiO2 has been first applied for producing blue cobalt-doped willemite pigments. The relevant variations of cobalt ions concentrations in SiO2–NaOH–ZnCl2–CoCl2–H2O system adequate with Zn2-xCoxSiO4 compositions where 0<x ≤ 0.92 and heat-treatment at 900 °C have yielded the pigments demonstrating a wide spectrum of blue tints. The optical characteristics of these pigments have revealed that Zn1·5Co0·5SiO4 pigment is distinguished by the highest absorption responsible for deepest blue hue similar to ultramarine. The comparison of their chromatic parameters with those of the identical ones produced by sol-gel routes has shown that the synthesized pigments with the compositions where x = 0.2 ÷ 0.5 manifest competitive color performances. The synthesis optimization has reduced calcination temperature up to 800 °C and stirring time up to 60 min. The homogeneity achieved in the intermediates by the suggested synthesis has yielded the pigments having uniform crystalline structure with controlled particle size. 120-minutes stirring has reduced the pigment particle size to dimensions less than 66 nm. Zn1.5Co0.5SiO4 pigment exhibits excellent color performances and tinting on heating up to 1200 °C and in wall tile glaze.

Effect of speed sintering and aging on the translucency of high-translucent zirconia.

This work aimed to evaluate the effect of speed sintering and low-temperature degradation on the translucency of high-translucent zirconia. The ST and TT specimens were randomly divided into two groups depending on the sintering process: conventional sintering and speed sintering. The sintered specimens were divided into three subgroups according to the aging time: aged for 0, 5, and 20 h. Chromatic parameters (L*, a*, and b* values) were measured by Shade Eye NCC computer colorimeter in a dark environment under black and white background, and the translucency parameter (TP) was used to evaluate the translucency of zirconia. Speed sintering may decrease the TP of ST and increase the TP of TT. As for the effect of low-temperature degradation on the translucency of zirconia, the TP of ST decreased with the extension of aging time, and no significant difference was found in rapid sintering ST. Although the TP of TT decreased, no statistical difference was observed. Speed sintering may decrease the translucency of high-strength zirconia and increase the translucency of high-translucent zirconia. Low-temperature degradation had no effect on the translucency of high-translucent zirconia. Speed sintering can be recommended for high-translucent zirconia in terms of translucency.

Color vision of people with headaches

The aim of the study is to obtain new data on possible changes in color vision of people with headaches. The object of the study is people who periodically experience primary headaches of different nature. The subject of the study is the specificity of perception of chromatic parameters of the environment and color sensitivity of people with headaches of different nature, quality, intensity and frequency. The data were collected using the Farnsworth-Munsell standard clinical color vision test (FM-100). The study involved 65 people aged 17 to 66 years. The results of the assessment of color vision in the experimental group were compared with the normative indicators and data obtained in the age-matched control group (N=40). Special attention was paid to discussing the possible causes of the identified disorders and analyzing the correlation between various aspects of headache with individual indicators of color sensitivity. The data analysis included calculating the total error (TES), as well as partial errors (PES) along the blue-yellow (B-Y) and red-green (R-G) axes. We also identified partial errors for individual tones. The study revealed a noticeable specificity in the perception of blue-green and blue shades of patients with severe, chronic and non-localized headaches. Since the detected color vision disorders appear to be temporary and are most likely typical of the premonitory phase of headaches, the results of this study may contribute to understanding of headache predictors. Since the identified changes relate to only one group of (blue) shades, the findings of the study can be used in the development of alternative treatment methods. In particular, in choosing the optimal color of tinted lenses, which are offered to patients to relieve headaches and reduce their frequency.

Flexible transparent wood with reversible photoresponsive property

Flexible photoresponsive transparent wood (FPTW) has potential applications in electronic equipment, sensors, and other fields. In this study, flexible and photoresponsive transparent wood was synthesized through the impregnation process, utilizing epoxy resin and a spiropyran solution. This process endowed the wood with intelligent response and flexible capabilities. Scanning electron microscopy (SEM) revealed the impregnation of the flexible polymer into the porous structure of natural wood. Further validation was conducted to affirm the sample responds to ultraviolet light, employing analyses of infrared spectroscopy, UV–visible spectroscopy, and X-ray photoelectron spectroscopy (XPS). Through the measurement of chromaticity parameters, encompassing lightness (L*), redness (a*), yellowness (b*), and total color difference (ΔE*), before and after UV irradiation, it is indicated that the wooden samples manifest commendable photoresponsive properties. Testing the fluorescence properties of the samples, the spiropyran completed the opened-loop and closed-loop transitions under irradiation with UV and visible light. In addition, the FPTW has excellent mechanical properties, with a tensile strength of 0.98 GPa and an elastic modulus of 0.65 GPa.

An insight into chromatic behaviour of jitter in pulsars and its modelling: a case study of PSR J0437−4715

ABSTRACT Pulse-to-pulse profile shape variations introduce correlations in pulsar times of arrival across radio frequency measured at the same observational epoch. This leads to a broad-band noise in excess of radiometer noise, which is termed as pulse jitter noise. The presence of jitter noise limits the achievable timing precision and decreases the sensitivity of pulsar timing data sets to signals of interest such as nanohertz-frequency gravitational waves. Current white noise models used in pulsar timing analyses attempt to account for this, assuming complete correlation of uncertainties through the arrival times collected in a unique observation and no frequency dependence of jitter (which corresponds to a rank-one covariance matrix). However, previous studies show that the brightest millisecond pulsar at decimetre wavelengths, PSR J0437−4715, shows decorrelation and frequency dependence of jitter noise. Here, we present a detailed study of the decorrelation of jitter noise in PSR J0437−4715 and implement a new technique to model it. We show that the rate of decorrelation due to jitter can be expressed as a power law in frequency. We analyse the covariance matrix associated with the jitter noise process and find that a higher rank approximation is essential to account for the decorrelation and to account for frequency dependence of jitter noise. We show that the use of this novel method significantly improves the estimation of other chromatic noise parameters such as dispersion measure variations. However, we find no significant improvement in errors and estimation of other timing model parameters suggesting that current methods are not biased for other parameters, for this pulsar due to this misspecification. We show that pulse energy variations show a similar decorrelation to the jitter noise, indicating a common origin for both observables.

Optimization of canola meal bleaching by hydrogen peroxide, protein extraction and characterization of their functional properties

The aim of the present work was to study the optimization of a process of canola meal bleaching with hydrogen peroxide. Effect of the bleaching on crude proteins extractability, their emulsifying and foaming properties were evaluated. The obtained results showed that hydrogen peroxide was highly effective for canola meal bleaching and its chromatic parameters were significantly improved. The bleached canola meal reached values of L* = 83.46, a* = −3.66, b* = 17.18 and BI = 18.05, making it compatible with commercial flours such as oat, rye, and whole wheat pastry flours. Protein extractability from the bleached meal was significantly enhanced up to 90 %. The functional properties evaluation of the extracted proteins from the bleached meal showed highly improved emulsifying and foaming properties. The extracted proteins from the bleached meal were mixed with canola oil and the analysis of the peroxide index did not show any oxidizing effect.

Development of Effective Infrared Reflective Coatings

The adsorption of surfaces exposed to sunlight results in increased temperatures that can cause physical damage and an increase in energy consumption. Infrared reflective coatings can keep objects cooler and have significant benefits in a wide variety of application by reflecting infrared light and decreasing heat, reducing operating costs, improving energy efficiency in buildings and vehicles, and extending an objects’ lifespan. The main aim of our research was to develop coatings in a RAL7016 Anthracite grey color with minimum heat adsorption in the infrared wavelength range. This was achieved using a combination of infrared transparent and infrared reflective pigment built-in coatings applied on two primers: white and black. Infrared reflectivity or transparency, as well as surface temperature, was investigated as a function of the composition and concentration of pigments. These coatings were characterized by chromatic parameters, by total solar and infrared solar reflectance in the UV, visible, and infrared wavelength range, and by heat reflection. Among the coatings developed, two produced very effective controls for infrared reflectance and transparency, and they could control heat reflectance, resulting in a significant decrease in surface temperature.

DRY-AGED BEEF: COLOR PARAMETERS AND SENSORY CHARACTERISTICS

Research work involves the instrumental analysis of the change in color (L*, a*, b*) and the sensory characteristics of the Simmental beef, parts of the carcass: T-bons, received from the local farm, during the dry-aging period for 0, 14, 21, 28, 35 days and for the roasted aged beef at high and very high temperatures. The analyzed beef samples presented uniform results for the chromatic parameters during the dry-aging period, being influenced by the values of meat pH and the water-holding capacity, namely: for the dry-aged meat, the L* parameter values indicate an increase in the brightness of the meat, for the a* parameter, decreasing values were established, which indicates a reduction in the oxygenation of the meat, a reduction of oxymyoglobin in meat, responsible for the intense red color and for the b* coordinate a slight decrease in values was observed, oriented to yellow color. For roasted beef parameter L* decreases due to the reduction of the beef moisture during the roasting process. The redness of beef a* decreases in intensity primarily depending on the beef aging period but also with the increase in the roasting temperature, due to the drastic degradation of myoglobin. The b* parameter also decreases, possibly due to the increase in metmyoglobin content during heat treatment. The sensory characteristics of the dry aged beef have been considerably improved due to the increase in the pH of the meat, which attracts the activation of meat-specific enzymes that contribute to the accumulation of secondary compounds with a major impact on the beef taste, aroma and juiciness. These aspects are later reflected on the sensory properties of the roasted aged beef, being intensified by the heat treatment process.

Exploitation of a Grafting Technique for Improving the Water Use Efficiency of Eggplant (Solanum melongena L.) Grown in a Cold Greenhouse in Mediterranean Climatic Conditions

Grafting techniques have been intricately associated with the optimization of water use efficiency (WUE). In this study, various eggplant (Solanum melongena L.) rootstock–scion combinations were compared under three irrigation regimes (IR): 50% deficit in water volume (IR50), a doubling of irrigation volume (IR200), and normal watering (IR100). The cultivar Black Bell (Bb) was employed as a scion, while the rootstock adopted included the F1 hybrids Energy (En) and Beaufort (Be) and one accession of S. torvum (To). The trial encompassed the evaluation of no- and self-grafted plants. Plants grown in a cold greenhouse in Sicily were assessed for their morphological parameters, as well as their fruit production and quality. The leaf analysis encompassed the evaluation of chromatic parameters and water potential. Significant variation was observed for plant height, exhibiting the lowest values in self-grafted combinations. The leaf water potential varied significantly in relation to the rootstock–scion combination employed and to the irrigation regime. Fruit quality traits displayed significant variations for chromatic parameters L* and a*, as well as for the fruit’s longitudinal and transversal diameters and the soluble solid content. The number of fruits and fruit production per plant varied significantly in relation to the rootstock–scion combination; the highest fruit production was recorded for Black Bell grafted onto S. torvum grown by IR50. The fruit weight displayed a significant interaction between the experimental factors under study. Notably, for the WUE calculated in relation to fruit production, a significant interaction between the experimental factors studied was ascertained. The highest WUE was registered for IR50, specifically for To/Bb. This research aims to develop a comprehensive water-efficient organic farming protocol for sustainable agriculture.

Effect of Bioactive Compounds from Pumpkin Powder on the Quality and Textural Properties of Shortbread Cookies.

The problem of food with functional ingredients, characterized by low energy intake and a variety of phytonutrients with biological activity, is one of the concerns of the population. The objectives of this study were to investigate the effect of pumpkin powder and its bioactive components on the quality, color and textural properties of shortbread cookies. In the drying process of pumpkin powder (Cucurbita moschata) at 60 ± 2 °C, the physicochemical parameters did not change significantly in relation to fresh pulp. The chromatic parameters L*, a* and b* showed that the pumpkin powder was brighter than the pulp, with a greater presence of yellow pigments. Pumpkin powder presented a rich source of bioactive compounds (polyphenols flavonoids, carotenoids) with an antioxidant potential of 161.52 mmol TE/100 g DW and 558.71 mg GAE/100 g DW. Antimicrobial activity against Gram-positive (Staphylococcus aureus, Bacillus cereus), Gram-negative (Escherichia coli, Salmonella Abony and Pseudomonas aeruginosa) bacteria and high antifungal activity against Candida albicans were attested. The sensory, physicochemical, texture parameters and color indicators of shortbread cookies with yellow pumpkin powder (YPP) added in a proportion of 5-20% were analyzed. The optimal score was given to the sample of 15% YPP. The use of 15-20% YPP contributed to improved consistency due to the formation of complexes between starch and protein.

B72 vs. Paraloid B67 Materials for Conservation of Wood Artifacts

Abstract The aim of the paper is a comparative testing of two Paraloid resins (B-72 and B-67), in order to determine which is the most efficient for the protection of wood artifacts. Healthy Spruce wood samples were cut (3cm ×3cm ×0.7cm) and covered by brushing with 3 layers of a Paraloid B 72 10% solution (solvent acetone: ethanol 1:1) and with a solution of Paraloid B 67 10% (solvent isopropanol) respectively. The samples further undergo rapid thermic aging and then, one set will undergo colorimetric testing in order to establish the degree of yellowing for each copolymer. Another set will undergo spectrometric FT-IR analysis in order to establish the degradation degree of the polymeric chains. The aim is also to compare the degree of water absorption for the wood samples treated with each of the two Paraloid resins. Also, the chromatic parameters and glossmetry values have been used as additional data in order to observe the degradation aspect of these samples.