Types Of Pigments Research Articles

The effect of new LED lighting systems on the colour of modern paints

This research focuses on the investigation of the effect of a new light emitting diode (LED)-lighting system which reproduces indoor museum conditions, on some self-made art paint colours (acrylic-, alkyd-, and linseed oil-based paints) often used in modern-contemporary art. A halogen lamp representing a traditional light source for museum lighting was also considered. Lighting-set-up and lighting optimization parameters were considered while Ultraviolet/Visible/Near Infrared (UV/Vis/NIR) spectrophotometry was used for investigating the colour change of the paint samples. Univariate analyses allowed determining the highest effect of the lighting systems on the linseed oil binder and ultramarine blue PB29 mixture upon ageing, according to the highest total colour change ΔE*ab. In a more specific and detailed way, variance analyses not only demonstrated the strong correlation between the type of binder and pigment used for the paint samples with the colour variation, but also showed that the short-wavelength blue LEDs influenced the change along the yellow–blue b* axis of the yellow and blue samples, whereas the halogen lamp mostly had an impact towards the red–green a* axis of mostly the green specimens.

A Study on the Retouching Materials for Oil Paintings - Using Restoration Colors and Acrylic Gouache -

In this study, we compare the properties and estimate the durability of five oil colors that are the most popularly used colors in the conservation of oil paintings. A set of these colors was obtained form four manufacturers each, and their properties were analyzed by conducting deterioration experiments. Subsequently, we observed the colors and performed X-ray fluorescence analysis. As a result of colour observation and XRF analysis, it was confirmed that there are the differences according to the pigment types, mixing rations and the manufacturers even for colors having the same product name. The deterioration test indicated differences in the appearance of the colors ; for instance, the color difference was above 12.0 in most of the samples, including restoration color and acrylic gouache. In the case of Lemon Yellow a lot of discoloration and cracking occurred, and difference in gloss was ob served in Viridian of manufacturer C. Most cracks were ob served in the restoration color obtained from manufacturer B and were assumed to be because of the resin used by the manufacturer. Nevertheless, additional research will have to be conducted by controlling variables in order to find out the cause. Through this study, we demonstrated that retouching materials for conservation of oil painting differed in their physical properties according to the color and manufacturer. Therefore a conservator should be mindful during the selection and use of materials for retouching oil paintings.

Analysis of pigments and damages for the 19th century White-robed Water-moon Avalokitesvara Painting in Gongju Magoksa Temple, Republic of Korea

The White-Robed Water-Moon Avalokiteshvara painting displayed on the rear wall of Daegwangbojeon (main hall) in Magoksa temple, is one of the representative Buddhist paintings in the late nineteenth century of Korea, and a valuable resource for understanding the coloring techniques and characteristics of Buddhist paintings in terms of expression and description in landscape painting. In this painting, the contours and colored surface remain undamaged, but blistering and exfoliation appear on some pigment layers. Furthermore, the partial decomposition of wooden materials due to wood-decay fungi and insect damage were found on the rear wall requiring proper treatment for long-term conservation. As the results of chromaticity and P-XRF analysis regarding the color pigment layer of the painting, the pigments were classified into ten types. The results suggest that the colors other than blue, green, yellow, red, black, and white were prepared by mixing two or more pigments. The types of pigments according to colors, were determined as traditional pigments with azurite; emerald green or clinoatacamite; 0 massicot; minium or hematite; Chinese ink; and kaolin, white lead, and gypsum, respectively. Violet and pink colors were assumed to have been prepared by mixing white with blue and red. In most of these pigments, small amounts of synthetic compositions from the modern era were detected at many points.

Predicting the Effectiveness of Mg-Rich Primers in Mitigating Galvanic Corrosion of Al Alloys Coupled with SS316 Fasteners Using Finite Element Modeling

Aerospace aluminum alloys, such as AA2024-T3 and AA7075-T6, are widely used in aerospace applications due to their high strength-to-weight ratio. However, because of their heterogeneous microstructure, they are susceptible to localized corrosion in chloride-containing environments. Corrosion attack is aggravated at fastener/sub-structure joining locations, where the Al alloy is in contact with more noble alloys, such as stainless steels. To protect these structures against corrosion attack, organic coatings are commonly used. Typical coating systems are usually composed of three layers: a conversion coating, a primer, and a topcoat. Historically, Al alloys have been protected by chromate-based coating systems. However, Cr(VI) has carcinogenic effects; thus, environmental regulations are restricting its use, stimulating the research in alternative corrosion protection technologies. Metal-rich primers, such as Mg-rich primers, have emerged as an effective and environmentally-friendly alternative to chromate-based primers. Depending on the type of the metallic pigment, these primers can provide chemical and electrochemical protection mechanisms to Al alloys.Localized corrosion of coated Al alloys can be affected by a vast number of variables, such as water layer thickness, electrolyte chemistry, salt loading density, pigment volume concentration of primer, chemistry of the primer, galvanic effects of pigment and noble fasteners, and component geometry. Thus, it is difficult to predict and quantify damage by localized corrosion, in addition to the efficacy and lifetime of a coating system. In this context, modeling can be used as a valuable assessment of parameter space, increasing the efficiency of experimental work. The objective of this work was to model the protection mechanisms offered by MgRP and investigate the influence of different environmental and geometric parameters on the effectiveness of the MgRP protection mechanisms in mitigating galvanic corrosion around fastener/substructure joints. The mechanisms of importance include protection via (a) the Mg pigment particles acting as sacrificial anodes, (b) the barrier to ion transport affected by the organic coating, and (c) changes in the electrolyte chemistry from the dissolution of the Mg pigment particles. The models consider each of these protection mechanisms in isolation as well as in combination. Ultimately, this model will provide a better understanding and prediction of the protection mechanisms of the MgRP, and it will elucidate critical conditions that should be further investigated with experimental work.Acknowledgements:Financial support from the SERDP program through the Office of Naval Research (C. Sanders) via Contract N00173-19-1-G011 as well as the DOD Corrosion Program Office through the US Air Force Academy via Contract FA7000-18-2-0006 is gratefully acknowledged. Technical discussions with Prof. John Scully (University of Virginia) and Dr. R.J. Santucci (Naval Research Laboratory) are also gratefully acknowledged.

An Insight into Anti-Inflammatory Activities and Inflammation Related Diseases of Anthocyanins: A Review of Both In Vivo and In Vitro Investigations.

Anthocyanin is a type of flavonoid pigment widely present in fruits and vegetables. It can not only be used as natural pigment, but also has a variety of health functions, for instance, anti-oxidant, anti-inflammatory, anti-tumor, and neuroprotective activities. Persistent proinflammatory status is a major factor in the development, progression, and complications of chronic diseases. Not surprisingly, there are thus many food ingredients that can potentially affect inflammation related diseases and many studies have shown that anthocyanins play an important role in inflammatory pathways. In this paper, the inflammation related diseases (such as, obesity, diabetes, cardiovascular disease, and cancer) of anthocyanins are introduced, and the anti-inflammatory effect of anthocyanins is emphatically introduced. Moreover, the anti-inflammatory mechanism of anthocyanins is elaborated from the aspects of NF-κB, toll like receptor, MAPKs, NO, and ROS and the main efficacy of anthocyanins in inflammation and related diseases is determined. In conclusion, this review aims to get a clear insight into the role of anthocyanins in inflammation related diseases.

Major Flower Pigments Originate Different Colour Signals to Pollinators

Flower colour is mainly due to the presence and type of pigments. Pollinator preferences impose selection on flower colour that ultimately acts on flower pigments. Knowing how pollinators perceive flowers with different pigments becomes crucial for a comprehensive understanding of plant-pollinator communication and flower colour evolution. Based on colour space models, we studied whether main groups of pollinators, specifically hymenopterans, dipterans, lepidopterans and birds, differentially perceive flower colours generated by major pigment groups. We obtain reflectance data and conspicuousness to pollinators of flowers containing one of the pigment groups more frequent in flowers: chlorophylls, carotenoids and flavonoids. Flavonoids were subsequently classified in UV-absorbing flavonoids, aurones-chalcones and the anthocyanins cyanidin, pelargonidin, delphinidin, and malvidin derivatives. We found that flower colour loci of chlorophylls, carotenoids, UV-absorbing flavonoids, aurones-chalcones, and anthocyanins occupied different regions of the colour space models of these pollinators. The four groups of anthocyanins produced a unique cluster of colour loci. Interestingly, differences in colour conspicuousness among the pigment groups were almost similar in the bee, fly, butterfly, and bird visual space models. Aurones-chalcones showed the highest chromatic contrast values, carotenoids displayed intermediate values, and chlorophylls, UV-absorbing flavonoids and anthocyanins presented the lowest values. In the visual model of bees, flowers with UV-absorbing flavonoids (i.e., white flowers) generated the highest achromatic contrasts. Ours findings suggest that in spite of the almost omnipresence of floral anthocyanins in angiosperms, carotenoids and aurones-chalcones generates higher colour conspicuousness for main functional groups of pollinators.

Multi-Scale Characterization of Unusual Green and Blue Pigments from the Pharaonic Town of Amara West, Nubia

Pigments from paint palettes and a grindstone excavated from the pharaonic town of Amara West (c. 1300–1050 BCE), which lies between the Second and Third Cataracts of the Nile, were examined using polarized light microscopy, attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), X-ray diffraction, and scanning electron microscopy with energy dispersive X-ray spectroscopy. Most of the pigments were consistent with the typical ancient Egyptian palette, but the greens and some blues were unusual. Two types of green pigment were identified, chlorite (varieties clinochlore and penninite) and copper chloride hydroxide (atacamite type). The former constitutes a type of green earth which has only rarely been identified in pharaonic Egyptian contexts and may be more widespread than is currently reported. The majority of the blue pigment samples were Egyptian blue, but some were found to be a blue earth, the main component of which being sodic amphibole riebeckite. The use of this mineral as a pigment has not previously been reported in any Nile Valley context. These results prompt questions around local and potentially indigenous practices within an ancient colonial context, and highlight avenues for future research.

Phylogenetic and Phenogenetic Diversity of Synechococcus along a Yellow Sea Section Reveal Its Environmental Dependent Distribution and Co-Occurrence Microbial Pattern

Synechococcus is a dominant genus of the coastal phytoplankton with an effective contribution to primary productivity. Here, the phylogenetic and phenogenetic composition of Synechococcus in the coastal Yellow Sea was addressed by sequencing marker gene methods. Meanwhile, its co-occurrence pattern with bacterial and eukaryotic microbes was further investigated based on the construction of networks. The result revealed that Synechococcus abundance ranged from 9.8 × 102 cells mL−1 to 1.6 × 105 cells mL−1, which was significantly correlated to sampling depth and nutrient contents of nitrite, ammonia, and dissolved silicon. A total of eight Synechococcus phylogenetic lineages were detected, of which clade III was dominant in most of the samples. Meanwhile, clade I increased along the water column and even reached a maximum value of 76.13% at 20 m of station B. Phenogenetically, Synechococcus PT3 was always the predominant pigment type across the whole study zone. Only salinity was significantly correlated to the phenogenetic constitution. The networks revealed that Synechococcus co-occurred with 159 prokaryotes, as well as 102 eukaryotes including such possible grazers as Gymnodinium clades and Alveolata. Potential function prediction further showed that microbes co-occurring with Synechococcus were associated with diverse element cycles, but the exact mechanism needed further experimentation to verify. This research promotes exploring regularity in the genomic composition and niche position of Synechococcus in the coastal ecosystem and is significant to further discuss its potential participation in materials circulation and bottom-up effects in microbial food webs.

Costs and Limitations of Marine Synechococcus Blue-Green Chromatic Acclimation

Benefits and trade-offs of blue/green chromatic acclimation (CA4) have received limited study. We investigated the energetic costs associated with executing chromatic acclimation using a fluorescence-based calculation of light use efficiency. Using laboratory cultures and artificial light environments, we show that the delayed response to acclimation known to occur in marine Synechococcus acclimating strains (generalists) in green light do not reduce light use efficiency in green light, but that only one generalist, RCC307, with a much smaller range of acclimation, had higher light use efficiency than blue and green light specialist strains. Generalists with a wider acclimation range either had the same or >30% lower light use efficiencies in blue and green light environments. From this work, we propose that advantages from CA4 may not be geared at direct competition with other Synechococcus specialists with fixed pigment types, but may serve to expand the ecological range of Synechococcus in spectral competition with other genera. As all eight Synechococcus strains tested had higher light use efficiency in green light, regardless of a fixed or flexible light harvesting strategy, we add evidence to the suitability of the Synechococcus genus to greener ocean niches, whether stable, or variable.

Treatment of Dye Waste Water using Moving Bed Biofilm Reactor and Granular Activated Carbon with Neem Leaf Powder

In recent days, the waste productions from industries are increased and direct discharge of wastes causes various pollution to the environment. Wastewater treatment in textile and dye industry mainly involves treatment of highly colored wastewater containing variety of dyes in different concentrations. The dyeing industries using different types of pigments and dyes of various concentration during their several production steps. These industries discharge a wastewater which contains organic substance, high colour with high COD and low concentration of BOD. This dye waste water are directly discharge in to the streams and thus contaminate the groundwater. To treat the wastewater, which is discharge from the dyeing industries a simple physio-chemical treatment is not sufficient for the removal of pollutants. So that a biological treatment followed with a physio-chemical treatment have been required. In this study, the experiment was carried out to reduce the organic substance, high colour, COD, BOD, and Heavy metals from dye wastewater using the laboratory scale Moving Bed Biofilm Reactor followed with Granular activated Carbon bed (GAC with NLP-MBBR) with Neem leaf powder. A various thick granular activated carbon bed was used for adsorption technique and for biological treatment of wastewater. The GAC with 8cm thick is layered followed by Ennore sand with 3 grades with 4cm thick equally. Then the MBBR was operated continuously with various retention times. The polypropylene type bio balls were used for microorganism attachment in MBBR. The outlet water from the MBBR are treated using membrane process. Membrane process using moving membranes reduces the pH, organic contents, heavy metals, COD, BOD, turbidity etc., The final effluent water is suitable for Irrigation.

Investigation of wafers used as paper binding in the academician von Struve manuscripts

This work is devoted to the study of the composition of such a characteristic object for the 17–19 centuries as wafers, which were used to join sheets of paper in documents or to seal letters. Owing to the limited information in the literature and possible degradation processes that may occur with them in this paper, the modern optical techniques were applied to gain information about them. As the object of the investigation the wafers found in the hand-written documents of Academician Friedrich Georg Wilhelm von Struve (Vasily Yakovlevich Struve 1793–1864) were chosen (Fund number 721, the RAS Archive, Saint-Petersburg branch, Struve V.). Besides the common way it was found that a large number of colored wafers were used to join several sheets in one composite elongated document and also to make correction on top of what was written. As the part of a major task aimed at maintaining the fund documents dated 19th century and the stability of the used joining wafers in particular the Raman and UV–Vis absorbance spectroscopies were applied in order to investigate wafers chemical composition. It was found the use of two different types of pigments for orange hues. One of them is cinnabar and another one is made up of red lead and massicot mixture. The Prussian blue was used for wafers with dark blue hue and as a mixture with massicot for green hue. According to UV–Vis absorbance spectroscopy it was found the use of anthraquinone type pigment for the red, rose and purple hues. The presence of the wafers with different base materials were determined by means of the Raman spectroscopy, namely of the vegetable (presumably starch) and protein (presumably gelatin) origin. The obtained results were compared with the data available in the previous researches, including the recipes given in the publications of the 19th century.

The effect of paper coatings containing biopolymer binder and different natural pigments on printability

Abstract Paper is an environmentally friendly, recyclable material whose main material is cellulose, which can be obtained from all kinds of trees and plants, used as writing, printing and packaging material. Due to its structural properties, papers are not resistant to temperature and humidity, as well as problems with ink transfer with its porous structure and experienced negative printability properties. In recent years, especially the growth of the packaging industry has increased the demand for papers with improved printability properties. In order to obtain better printability properties from papers, some processes can be performed in paper production, as well as some surface treatments after production. These processes are paper coating, sizing and calendering. Paper coatings are generally water-dispersed coating solutions with one or more pigments, binders and certain additives to improve the desired properties. With these processes, by filling the gaps between the pores of the paper, a shapely and smooth surface is obtained and good printability is obtained together with the optical and physical properties of the papers. In this study, the interactions and printability properties of different types of pigments with xanthan gum binder were investigated by preparing paper coating formulations using calcium carbonate, barite and talc pigments and xanthan gum as binder. As a result, xanthan is a good coating binder and CaCO 3 {\mathrm{CaCO}_{3}} from the compared pigments is the most suitable compared to the other 2 pigments, considering all the studied areas.

The conformity between dermoscopy imaging and Wood’s lamp diagnostic on periorbital hyperpigmentation

Introduction: Periorbital hyperpigmentation (POH) is a common skin problem characterized by homogeneous/dark brown hyperchromic/pigmented macules around the lower eyelid and upper eyelid up to the malar area temporal area and the sides of the nose. POH is a multifactorial condition caused by both endogenous factors and exogenous factors, without one aspect dominating. Dermoscopy and Wood's lamp can assist the diagnosis of POH types when the inspection is regarded as weak. The assessment of the suitability of the dermoscopic image and Woods’ lamp diagnosis indicates an alternative supporting test in POH diagnosis. This study aimed to examine the conformity between dermoscopic images and Wood's lamp examination in POH diagnosis.Methods: This observational conformity study was conducted using a cross-sectional design. There were 38 subjects diagnosed with POH who went to the Cosmetics Division of Dermatology and Venereology, Universitas Sumatra Utara Hospital participated as subjects. Assessments regarded the types of POH analyzed based on dermoscopic images and Wood's lamp examination. Data analysed with SPSS version 20 using Kappa test.Results: On dermoscopy examination, the mixed type was the type most obtained, as many as 18 subjects (47,4%), whilst on Wood's lamp examination, the most dominant type obtained was pigment type, as much as 21 subjects (55,3%). Moderate conformity value on POH examination was obtained with dermoscopy and Wood’s lamp.Conclusion: Dermoscopic images and Wood's lamp examination shared a sufficient conformity value in POH diagnosis.

Oxidative stress in the skin: Impact and related protection.

Skin, our first interface to the external environment, is subjected to oxidative stress caused by a variety of factors such as solar ultraviolet, infrared and visible light, environmental pollution, including ozone and particulate matters, and psychological stress. Excessive reactive species, including reactive oxygen species and reactive nitrogen species, exacerbate skin pigmentation and aging, which further lead to skin tone unevenness, pigmentary disorder, skin roughness and wrinkles. Besides these, skin microbiota are also a very important factor ensuring the proper functions of skin. While environmental factors such as UV and pollutants impact skin microbiota compositions, skin dysbiosis results in various skin conditions. In this review, we summarize the generation of oxidative stress from exogenous and endogenous sources. We further introduce current knowledge on the possible roles of oxidative stress in skin pigmentation and aging, specifically with emphasis on oxidative stress and skin pigmentation. Meanwhile, we summarize the science and rationale of using three well-known antioxidants, namely vitamin C, resveratrol and ferulic acid, in the treatment of hyperpigmentation. Finally, we discuss the strategy for preventing oxidative stress-induced skin pigmentation and aging.

Large-area fabrication of colorful superhydrophobic coatings with high solar reflectivity

In the present work, the colorful superhydrophobic coating with high solar reflectivity was prepared using WPC (White Portland cement), color pigments, Polymethylhydrosiloxane and water as raw materials. The superhydrophobicity of the coating surface comes from the combination of the micron/sub-micron rough structure formed by the accumulation of cement hydration products and pigment particles and the low surface energy provided by PMHS (Polymethylhydrosiloxane). The superhydrophobic coating exhibits excellent resistance to corrosion of aggressive solutions, pollution of liquid foods, and accumulation of dust. The SR (Solar reflectance) of superhydrophobic coatings was optimized by changing the type, content and collocation of pigments. The results show that the superhydrophobic coating filled WP (with white pigment) and YP (yellow pigment) has the best performance. The optimized coating is yellowish brown with IR reflectance of 0.8191 and SR of 0.6569, which meets the building energy saving standard. The results of solar radiation experiments show that the surface temperature of the yellow–brown superhydrophobic coating is reduced by 5.7 °C compared with the ordinary Portland cement coating, which has a significant cooling effect. The colorful superhydrophobic coatings also possessed excellent weatherability and high mechanical robustness. Therefore, the coating developed in this work can be used on the exterior wall and roof of the building to reduce the energy consumption of the building in summer.

A hybrid yellow nanopigment as an environmentally sound alternative to lead chromate pigment for pavement markings

This study entails the synthesis of a series of yellow hybrid dye-clay nanopigments (DCNPs) using different yellow cationic dyes, natural, and organomodified montmorillonite. The cationic exchange reaction served as a facile, one-pot, and low-temperature transformation strategy. DCNPs are explored as a type of lead-free eco-friendly pigment to substitute for conventional lead chromate pigment (PbCrO4) for pavement markings. The plate-like DCNP stacks with an approximate hydrodynamic diameter of 2.1 μm were well-dispersed in paint film, forming partially intercalated/exfoliated structure. DCNPs exhibited higher thermal stability, weathering stability, and chemical stability than PbCrO4. DCNPs featured the brilliant yellow shade in pavement marking paint, with the blue-yellow component value (b*) up to 69.9 units. The American pavement marking reference colors can be achieved with a considerably smaller amount of colorant when using DCNP, owing to its exceptional color strength. The cytotoxicity analysis revealed 91%, 66%, and 2% viability of fibroblast cells after a 48h treatment with 0.25 mg/ml natural DCNP, organoclay-based DCNP, and PbCrO4, respectively. In conclusion, the remarkable functional properties and low acute toxicity of the resulting nanopigments suggested the potential application of DCNP as a promising alternative to lead-based pigments in pavement markings.

Effect of nonthermal treatments on selected natural food pigments and color changes in plant material.

In recent years, traditional high-temperature food processing is continuously being replaced by nonthermal processes. Nonthermal processes have a positive effect on food quality, including color and maintaining natural food pigments. Thus, this article describes the influence of nonthermal, new, and traditional treatments on natural food pigments and color changes in plant materials. Characteristics of natural pigments, such as anthocyanins, betalains, carotenoids, chlorophylls, and so forth available in the plant tissue, are shortly presented. Also, the characteristics and mechanism of nonthermal processes such as pulsed electric field, ultrasound, high hydrostatic pressure, pulsed light, cold plasma, supercritical fluid extraction, and lactic acid fermentation are described. Furthermore, the disadvantages of these processes are mentioned. Each treatment is evaluated in terms of its effects on all types of natural food pigments, and the possible applications are discussed. Analysis of the latest literature showed that the use of nonthermal technologies resulted in better preservation of pigments contained in the plant tissue and improved yield of extraction. However, it is important to select the appropriate processing parameters and to optimize this process in relation to a specific type of raw material.

Pterin-based pigmentation in animals

Pterins are one of the major sources of bright coloration in animals. They are produced endogenously, participate in vital physiological processes and serve a variety of signalling functions. Despite their ubiquity in nature, pterin-based pigmentation has received little attention when compared to other major pigment classes. Here, we summarize major aspects relating to pterin pigmentation in animals, from its long history of research to recent genomic studies on the molecular mechanisms underlying its evolution. We argue that pterins have intermediate characteristics (endogenously produced, typically bright) between two well-studied pigment types, melanins (endogenously produced, typically cryptic) and carotenoids (dietary uptake, typically bright), providing unique opportunities to address general questions about the biology of coloration, from the mechanisms that determine how different types of pigmentation evolve to discussions on honest signalling hypotheses. Crucial gaps persist in our knowledge on the molecular basis underlying the production and deposition of pterins. We thus highlight the need for functional studies on systems amenable for laboratory manipulation, but also on systems that exhibit natural variation in pterin pigmentation. The wealth of potential model species, coupled with recent technological and analytical advances, make this a promising time to advance research on pterin-based pigmentation in animals.

A new thermal insulation ceramic pigment: Ce-doped Y3Al5O12 compounds combined with high near-infrared reflectance and low thermal conductivity

In this work, we explored NIR reflectivity and thermal conductivity of Y3-xCexAl5O12 compounds (x = 0.05, 0.1, 0.15, 0.2) as thermal insulation pigments. The test results show that the phase structure still retained the cubic phase and the morphology presents a curved worm-shaped. Also, cerium occurs in its mixed-valence state (+3, +4) in the Ce-doped Y3Al5O12. The prepared compounds registered a high value of NIR solar reflectance in 700–2500 nm of light (76.47%−90.06%), and the variation in NIR reflectivity value was expounded in terms of free carrier concentration and the electron trap. The ceramic materials added with the Ce-doped Y3Al5O12 pigments exhibited a lower thermal conductivity (<0.3796 W/mk), compared with other conventional ones. Moreover, the composition displayed bright yellow colors, corresponding to the transition absorption of Ce3+ in the blue region from 4f to 5d. Application studies proved that the inner surface temperature of the ceramic substrate prepared with the synthesized pigment is 7.5 °C lower than the ordinary ceramic of the same color. This type of yellow ceramic pigment with optimal NIR reflectivity and low thermal conductivity exhibited potential applications in insulating ceramics.

Effect of addition of pigments on thermal characteristics and the resulting performance enhancement of asphalt

Lower thermal conduction and higher specific heat of conventional black pavement result in extreme surface temperatures during summers. Asphalt being highly temperature-dependent and viscoelastic, is more vulnerable to damage under vehicular loading at these temperatures. It also contributes towards Urban Heat Island (UHI) effect, hence demanding for non-black pavement surfaces by use of coloring additives which could help in the surface temperature reduction. Iron oxide red and Titanium dioxide white pigments are used to decolor the black mixes. Asphalt and bitumen samples were thermally investigated in heat sinks at three different solar fluxes. Pigment dosage was kept at 4% by weight of total mix for all the types of pigments. Samples were heated and cooled for 3 and 2 h, respectively. The effect of change in temperature of pigmented samples was also verified through performance testing. Cooper wheel tracking and dynamic modulus tests were performed to assess the high-temperature performance while fatigue parameters were assessed with a four-point bending beam fatigue test. Rheology of binder was assessed using Dynamic Shear Rheometer (DSR). Moreover, Rolling Bottle Test and Bitumen Bond Strength Test were also performed to check moisture sensitivity. Results showed that pigmented binder remain 8–10 ⁰C cooler while pigmented asphalt mixtures remain 4–5 ⁰C cooler as compared to unmodified samples. Performance tests reflected higher permanent deformation resistance at higher temperatures without compromising the fatigue property at lower temperatures. Rheology also depicted an increase in stiffness of pigmented binder, indicating better performance at higher temperatures. Use of pigments also enhances the moisture resistance/adhesion of the binder.