Protective Pigments Research Articles

Novel antifouling paint formulation based on Ca2​Cr2O5​ and CaMnO3​ NPs as a protective pigment

This work focused on the preparation of novel antifouling paint based on Ca2Cr2O5 and CaMnO3 NPs as a safe protective pigment which were replaced with cuprous oxide. Three paint formulations were prepared for comparison, a blank formula without an antifouling agent (F1), a commercial antifouling formula based on 100% cuprous oxide as an antifouling agent (F2), and AF formula based on 75% Ca2Cr2O5 and CaMnO3 NPs and 25% Cu2O. The high performance and durability of the paints based on the prepared pigments were evident from their impact resistance, adhesion, pending, hardness, and chemical resistance, which were compared to the blank formula (F1). The corrosion resistance of the painted films was also investigated using the salt spray test method, and the results were promising compared to the blank and standard formulations. All painted steel plates were exposed to seawater through field tests in the Suez Canal at Port Said for up to 6 months. The results showed that the paints based on F2 and F3a, b enhanced the antifouling activity through six months of exposure. The obtained results demonstrated greater efficiency of the painted steel-based F3a than F1 and F3b, and being comparable to the standard formula (F2).

Comparative Analysis of Dielectric Behavior under Temperature and UV Radiation Exposure of Insulating Paints for Electrical Equipment Protection—The Necessity of a New Standard?

This paper describes the behavior of some epoxy, acrylic and polyurethane paints used in the protection of electrical equipment under the action of different degradation factors. The degradation factors chosen were temperature and UV radiation. The behavior of the paints under the action of these factors was interpreted by the variation of the tangent of the dielectric loss angle (tg Delta) as well as by FTIR and TG DSC analyses. Tg Delta was considered the reference dielectric characteristic because it best simulates the functionality of the material. The results presented in this paper lead to the conclusion that exposure to thermal cycles and UV radiation is necessary for each paint to give indications about their possibility of use in these conditions. At the same time, the evaluation of thermal stability, even if the exposure is at lower temperatures (than those at which we performed the tests) and/or for shorter periods, is very important for placing the paint in an insulation class. The tests that were the subject of this work provide us with the following information about the three types of paints analyzed: the highest resistance to thermal cycles is presented by S3, followed by S2 and then S1; thermal endurance tests place the polyurethane paint (S3) in insulation class E and the epoxy paint (S1) in insulation class B; and the tests to determine resistance to UV radiation qualify the best paint as acrylic (S2) and the worst as polyurethane (S3). Thus, it can be said that in applications where it is necessary for the protective film to withstand high temperatures, the use of S3 paint (polyurethane) is recommended, and in applications where the films are kept under the influence of UV radiation for a longer time, it is recommended to use coded paint S2 (acrylic). The results presented in this paper lead to the conclusion that the exposure to thermal cycles simulating the use in outdoor conditions and the resilience of paints under UV radiation conditions must be performed for each paint according to its specific use, and the dielectric characteristics must be carefully evaluated because they can reach values under the accepted limit—e.g., thermal stability evaluation—even if the exposure is at lower temperatures and/or for shorter periods. The conclusions of the experimental work must be generalized at different types of electrical insulating paints, and maybe a new standard is necessary to assess the paints’ behavior under usage conditions, with the paints needing to be treated separately from the classical polymeric insulation systems.

Development and evaluation of antimicrobial PVC-grafted polymer for enhanced paint applications.

Demand for antimicrobial paints is increasing globally due to the rising need to control microbial growth and reduce infection risks in various environments. This increased demand underscores the crucial role of advanced antimicrobial coatings in promoting health and safety. In this context, an innovative poly(vinyl chloride) (PVC) grafted polymer with 1-(2-aminoethyl piperazine) (AEP) was prepared and studied in detail. In this study, the prepared polymer was characterized using FTIR and NMR spectroscopy to examine the polymer's chemical structure and employed TGA and DSC for thermal stability analysis. The antimicrobial activity of the grafted polymer was evaluated through the agar diffusion method and showed a significant inhibition zone of 21.6 mm for S. aureus, 16.3 mm for E. coli, 18.3 mm for M. smegmatis, and 20.3 mm for C. albicans at a lowest concentration of 12.5 μg mL-1. To assess surface characteristics, the PVC-g-AEP polymer was mixed with commercial paint and applied to a glass surface. SEM and AFM analysis showed a 5-times increase in porosity while maintaining visual aesthetics. Additionally, the paint displayed excellent stability against water, retaining around 90% of its antimicrobial activity even after 15 washes. This advanced polymer not only exhibits superior antimicrobial properties but also improves paint durability, setting a new benchmark for high-performance antimicrobial coatings and significantly advancing protective paint technology.

Polymeric Protective Films as Anticorrosive Coatings-Environmental Evaluation.

The behavior of two polymeric protective paint coatings (epoxy and polyurethane) applied over an epoxy primer coating on steel plates was investigated in this study, focusing on their role in providing anticorrosive protection against various climatic stress factors. Among the numerous climatic factors that can affect the lifetime of anticorrosive coatings, the following were selected for this work: dry heat, UV radiation, humidity, and extreme conditions such as salt fog, marine atmosphere, and alpine atmosphere. The objective was to determine the remaining lifetime of these protective coatings before replacement is needed to prevent damage to the equipment they protect. The behavior of these polymeric materials under the mentioned factors was analyzed based on the variation in the tangent of the dielectric loss angle (tg δ) with frequency. From the interpretation of the experimental results, it was found that the polyurethane paint coating (P2) exhibits superior resistance to climatic degradation compared to the epoxy paint coating (P1). Furthermore, a comparison of tg δ values for the P1 and P2 coatings revealed that the initial (unaged) P2 coating performs better as an insulator (dielectric) than the P1 coating. Comprehensive information is provided to the users of polymeric anticorrosive protection materials, highlighting the extent to which climatic factors can affect the performance of the equipment they protect and determining the appropriate timing for replacing the coatings.

Ecological investigations of giant Phaeocystis colonies in Viet Nam: I. Cell abundance and elemental composition.

Phaeocystis globosa is an important bloom-forming marine phytoplankton species that often accumulates to large levels in temperate and tropical waters and has significant impacts on food webs and biogeochemical cycles. It can form "giant" colonies that reach 3 cm in diameter. Microscopic observations, colony elemental composition, and pigment composition were analyzed to assess the characteristics of colonies as a function of colony size. Particulate organic carbon (POC) per unit surface area, colonial cell density, and chlorophyll a per unit surface area all increased with colony size, in contrast to results from temperate waters. Cellular chl a averaged 0.85 pg chl · cell-1. Colonies had both photosynthetic and protective pigments, with fucoxanthin being the dominant accessory pigment. Based on chl a and pigment levels, it appears colonies were acclimated to relatively low irradiances, likely due to their life cycle and the extremely turbulent environment in which they grew. Mucous carbon ranged from 16.2% to 79.2% of the total POC, and mucous carbon per unit surface area increased with colony size, suggesting that the mucous envelope did not thin as the colony grew. Based on elemental composition, nitrogen did not appear to limit growth, but phosphorus:carbon ratios were similar to those of P-limited cultures. Giant colonies represent an extreme response to the environment, but they do not appear to have greatly different characteristics than other tropical strains.

Green synthesis of ZnO-chitosan nanoparticles and vinyl resin with effective antifouling properties

The demand for non-toxic antifouling protective paint or coating, intended to restrict the development of germs on surfaces exposed to water, has witnessed a remarkable surge in recent times. In this study, From Avicennia Marina, ZnO nanoparticles were isolated, while chitosan nanoparticles were obtained from shrimp shells. The synthesis of hybrid nanoparticles comprising ZnO and chitosan was successfully achieved through reflux conditions. Assessment of the morphology and various approaches were used to determine the size of ZnO-chitosan hybrid nanoparticles, including as Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), X-ray spectroscopy (EDS), Field Emission Scanning Electron Microscopes (FE-SEM) and Dynamic light scattering (DLS). ZnO-chitosan hybrid nanoparticles' effectiveness was evaluated using a range of laboratory biological experiments. ZnO-chitosan hybrid nanoparticles were tested for their efficacy against Escherichia coli (E. coli) at a dose of 50 μg/mL, while their impact on Staphylococcus aureus (S. aureus) was tested at a concentration of 25 μg/mL. Furthermore, Isochrysis galbana was significantly inhibited by these nanoparticles, with an inhibition rate of approximately 99 % after 48 h. The panel with the best and most effective outcomes contained 3 wt% ZnO-chitosan hybrid nanoparticles (The lowest measured weight of biofouling was 30.997 g). The results suggest that hybrid nanoparticles comprising ZnO and chitosan, along with vinyl resin incorporation, exhibit superior performance in terms of antifouling, antibacterial, and antialgal properties compared to both ZnO and chitosan nanoparticles.

Interactions of Phenylalanine Derivatives with Human Tyrosinase: Lessons from Experimental and Theoretical tudies.

The pigmentation of the skin, modulated by different actors in melanogenesis, is mainly due to the melanins (protective pigments). In humans, these pigments' precursors are synthetized by an enzyme known as tyrosinase (TyH). The regulation of the enzyme activity by specific modulators (inhibitors or activators) can offer a means to fight hypo- and hyper-pigmentations responsible for medical, psychological and societal handicaps. Herein, we report the investigation of phenylalanine derivatives as TyH modulators. Interacting with the binuclear copper active site of the enzyme, phenylalanine derivatives combine effects induced by combination with known resorcinol inhibitors and natural substrate/intermediate (amino acid part). Computational studies including docking, molecular dynamics and free energy calculations combined with biological activity assays on isolated TyH and in human melanoma MNT-1 cells, and X-ray crystallography analyses with the TyH analogue Tyrp1, provide conclusive evidence of the interactions of phenylalanine derivatives with human tyrosinase. In particular, our findings indicate that an analogue of L-DOPA, namely (S)-3-amino-tyrosine, stands out as an amino phenol derivative with inhibitory properties against TyH.

Characterization of industrial TNT in ammunition shells: An in-depth study of artificial aging effects using Fourier-Transform infrared spectroscopy and gas chromatography–mass spectrometry

In this study, we comprehensively investigated the degradation of industrial trinitrotoluene (TNT), focusing on the effects of aging and direct contact with steel surfaces, mirroring real-world usage conditions. While practical knowledge exists regarding this degradation, the existing literature lacks in-depth insights into the underlying processes. To address this gap, we conducted experiments using small steel samples, representative of military ammunition casings, which were coated with TNT and subjected to 30 days of heating at 75 °C under vacuum conditions. A subset of these samples was coated with a protective red alkyd paint. After the aging process, the TNT was carefully removed from the metal surfaces and subjected to a comprehensive analysis encompassing scanning electron microscopy, Fourier-transform infrared spectroscopy, and gas chromatography-mass spectrometry. Our results reveal a remarkable preservation of the chemical integrity of industrial TNT, even in the presence of thermal stress and direct steel contact. Although superficial changes were observed in the TNT's appearance, all analytical data consistently demonstrated the maintenance of its chemical composition. Notably, the sole change in composition was attributed to the presence of degradation products associated with the alkyd paint coating, rather than intrinsic TNT degradation. These findings underscore the negligible impact of degradation processes on TNT in scenarios involving the solid-phase thermal stress of TNT in direct contact with metal, significantly enhancing our understanding of TNT safety when packaged within steel artifacts—a common context in military ammunition.

Trace metal and organic biosignatures in digitate stromatolites from terrestrial siliceous hot spring deposits: Implications for the exploration of martian life

Novel biosignatures of laminated, microbial, digitate sedimentary structures – stromatolites – from modern geothermal fields of the Taupō Volcanic Zone, New Zealand, and from El Tatio, Chile, provide an opportunity to investigate evidence of extremophile life preserved in siliceous hot spring deposits, or sinters, interpreted as analogs for early life on Earth and possibly Mars. Synchrotron-μXRF, electron microprobe analysis, Raman spectroscopy, and optical microscopy are used in a coordinated approach to identify corroborating textural and chemical (organic, inorganic) evidence of life in these modern, opaline (amorphous) siliceous materials. Fluid mobile elements, such as As and Sr, track the growth history of the digitate structures. Trace element enrichments of Ca, Al, Ga, +/− Fe, Mn, As, Rb, Cs, and Sr, are identified in silicified sheaths of microbial filaments embedded within the sinter. In contrast, silicified diatoms in some sinter samples show no trace element enrichment. Gallium enrichments have also been observed in other 16 ka and Jurassic (150 Ma) microbial palisade sinter textures, suggesting the potential for preservation through geologic time, even after recrystallization to quartz. Raman analysis reveals spectra of organics, consistent with pigments for UV protection in cyanobacteria, in silicified sheaths around microbial filaments and are co-located with trace metal enrichments in digitate structures. Due to spectral bands, the location of these molecules (i.e., in the sheaths), and the sampling locations, we ascribe the spectra to scytonemin and carotenoid class molecules. The combined analytical approach outlined here provides a robust means to assess the validity of novel biosignatures, with application to the exploration of Mars, where preservation of opaline silica in >3.6 Ga deposits has the potential to preserve a range of microbial biosignatures.

A wide range of modified alkyd resins based on a new source of dicarboxylic acid as a binder for anticorrosive paint

Purpose This paper aims to prepare alkyd protective paint by using modified alkyd with 3,6-dichloro benzo[b]thiophene-2-carbonyl glutamic acid (DCBTGA) as a source of dicarboxylic acid and evaluating their anticorrosive properties compared with those of unmodified alkyd coatings for steel protection. Design/methodology/approach Short, medium and long oil alkyds, which represented as (0, 10, 20 and 30% excess-OH) according to the resin constants (Patton, 1962), were prepared through a condensation polymerization reaction via a solvent process in a one-step reaction. The modification of alkyd was carried out by using DCBTGA as a source of dicarboxylic acid. The prepared modified alkyd was confirmed by IR and NMR spectral analysis. The physicochemical, mechanical and anticorrosion performance properties of the considered modified coating formulations against unmodified blank coating were studied to confirm their application efficiency. Findings The best results in terms of physicochemical, mechanical and anticorrosion performance properties were found according to the following of this order activity: 30 replacements of the modifier (DCBTGA) for each hydroxyl continent were 30% Ex-OH > 20% Ex-OH > 10% Ex-OH > 0% Ex-OH, compared with that formulation containing unmodified alkyd, especially with increasing the modifier percent. Originality/value The prepared DCBTGA-modified resins can be used for different applications based on the type of alkyd and application.

Silencing of Sporothrix schenckii GP70 Reveals Its Contribution to Fungal Adhesion, Virulence, and the Host-Fungus Interaction.

Sporothrix schenckii is one of the etiological agents of sporotrichosis, a cutaneous and subcutaneous infection distributed worldwide. Like other medically relevant fungi, its cell wall is a molecular scaffold to display virulence factors, such as protective pigments, hydrolytic enzymes, and adhesins. Cell wall proteins with adhesive properties have been previously reported, but only a handful of them have been identified and characterized. One of them is Gp70, an abundant cell wall protein mainly found on the surface of yeast-like cells. Since the protein also has a role in the activity of 3-carboxy-cis,cis-muconate cyclase and its abundance is low in highly virulent strains, its role in the Sporothrix-host interaction remains unclear. Here, a set of GP70-silenced strains was generated, and the molecular and phenotypical characterization was performed. The results showed that mutants with high silencing levels showed a significant reduction in the adhesion to laminin and fibrinogen, enzyme activity, and defects in the cell wall composition, which included reduced mannose, rhamnose, and protein content, accompanied by an increment in β-1,3-glucans levels. The cell wall N-linked glycan content was significantly reduced. These strains induced poor TNFα and IL-6 levels when interacting with human peripheral blood mononuclear cells in a dectin-1-, TLR2-, and TLR4-dependent stimulation. The IL-1β and IL-10 levels were significantly higher and were stimulated via dectin-1. Phagocytosis and stimulation of neutrophil extracellular traps by human granulocytes were increased in highly GP70-silenced strains. Furthermore, these mutants showed virulence attenuation in the invertebrate model Galleria mellonella. Our results demonstrate that Gp70 is a versatile protein with adhesin properties, is responsible for the activity of 3-carboxy-cis,cis-muconate cyclase, and is relevant for the S. schenckii-host interaction.

Estimation of the repeatability and reproducibility of test results in determining the degree of cure of protective paint coatings using differential scanning calorimetry

The degree of curing of protective paint-and-varnish coatings for oil country tubular goods is a parameter characterizing the completeness of their polymerization, and allows drawing a conclusion about the final physicomechanical properties and the possibility of using the material under specific conditions. This parameter is considered decisive in conducting acceptance tests and incoming quality control of pipe products with plated protective epoxy coatings despite a low accuracy of the obtained results and the impact of various instrumental factors and methodological approaches. The authors have developed a methodology for determining the curing degree of coatings based on the procedures given in regulatory documents (CSA Z245.20 Series-18, GOST R ISO 21809-2), taking into account the analysis of factors affecting the results of determining the curing degree carried out in the previous work. According to the conducted studies, the rates of heating and cooling during the measurement process, the temperature test program (in particular, the presence and duration of isothermal exposures before heating cycles), and curve processing methods were corrected and selected in the proposed methodology. The aim of this work is the analysis of the precision of the developed method for determining the curing degree of protective coatings to confirm the high accuracy of the obtained values under observing the prescribed procedure. The analysis was carried out by statistical processing of the results obtained in comparative tests performed in four testing laboratories, and included calculation of the repeatability of the results by their standard deviation, reproducibility and assessment of the acceptability of these parameters. The developed procedure for determining the curing degree of protective coatings, from sampling to processing of DSC curves, showed good precision, which indicates the reproducibility and repeatability of the proposed method. The developed method can be used as a unified sequence for determining the curing degree of paints and varnishes used as protective coatings in different laboratories.

Sebacate intercalated Ca[sbnd]Al layered double hydroxide pigments for corrosion protection of low carbon steel: Anion exchange and electrochemical properties

Sebacate (SB) molecules were incorporated into CaAl layered double hydroxides (CaAL-LDH) using a hydrothermal method. The resulting products underwent characterization through X-ray diffraction, infrared spectroscopy, and scanning electron microscopy. To investigate the release kinetics and thermodynamics of the corrosion inhibitor, total organic carbon analysis (TOC) was employed. A comparison was made with CaAl-LDH prepared without corrosion inhibitors, in which nitrates were the primary anions within the layered clay structure. An assessment of anion exchange between nitrates and chlorides was conducted using total nitrogen analysis (TN). The SB anion comprised approximately 49.2% of the total dried powder synthesized, with a maximum release efficiency of around 86.7% fitting a Langmuir model. For the evaluation of the corrosion inhibition effect on steel surfaces, electrochemical impedance spectroscopy, potentiodynamic polarization, and scanning vibrating electrode technique were employed. The corrosion inhibition impact was ascribed to the liberation of SB anions from the CaAl-LDH pigments, accompanied by alkalinization stemming from partial particle dissolution. Additionally, the incorporation of organic molecules notably enhanced the stability of pigments in aqueous solutions compared to similar ones hosting nitrates. These findings suggested that CaAl-LDH pigments have potential as nanocontainers for organic inhibitors, showing promising prospects in the field of corrosion research.

A review on the environment friendly electroplating of Cr (III) & Cr (VI)

Chromium plating process is the most effective way of protecting the base material against hostile environment or improving surface properties of base material. There are several problems with traditional chrome plating. Traditional process uses toxic acid baths and may cause various health conditions. The baths employed contain chromic acid in which the chromium is in the hexavalent state. Hexavalent chromium has been proved to have toxic, mutagenic and cancerogenic effects for human health. As a result, In Europe, the implementation of the reach initiative will increase fees on companies still using Cr (VI) in 2017 and will require action plans to phase out Cr (VI) in the future. This has left the plating industry in a very delicate position with dark future prospects unless new solutions that are both effective and environmentally friendly are discovered. Superchrome Physical Vapor Deposition coating ahead of looming industry regulatory actions that will drive towards the removal of hazardous hexavalent chromium compounds. These new sputtered chromium coatings do not require a protective paint top coat to pass exterior automotive trim specifications. Visually the chromium coatings match those of electroplated decorative chromium in color and appearance.

Technological Aspects of Ensuring the Quality of Protective Coatings of Building Metal Structures

This article discusses issues related to the development of technological solutions designed to obtain protective paint and varnish coatings with high operational resistance for building metal structures. The developed technological map and scheme for creating nanostructured paint and varnish coatings on the surfaces of building metal structures are presented. These proposals complement the comprehensive approach to the development of protective paint and varnish coatings, consisting of methodological, technological and formulation solutions, and presented in other studies by the authors, which allows for its effective use in paint and varnish industry enterprises. The research results, based on the application of the developed solutions in laboratory and operational conditions, confirm the high efficiency of the developed integrated approach. Assessment of the quality of coatings in laboratory conditions showed that coating samples after 100 hours of thermal exposure retain high properties that meet the operating conditions of building metal structures. As part of production testing, it was established that the service life of nanostructured coatings increases by 1.5–2.6 times compared to traditional coatings. In this regard, the costs of repair and restoration of coatings are reduced, and their service life between repairs is increased. The introduction of the developed solutions into production will solve the problem of low operational durability of protective paint and varnish coatings of steel building metal structures operated under various influences.

Mimicking Natural Antioxidant Systems for Improved Photostability in Wide-Band-Gap Perovskite Solar Cells.

Fostered by the top power conversion efficiencies (PCEs) of lab-scale devices, industrialization of perovskite solar cells is underway. Nevertheless, the intrinsically poor stability of these materials still represents a major concern. Herein, inspired by Nature, the use of β-carotene in perovskite solar cells is proposed to mimic its role as a protective pigment, as occurs in natural photosynthesis. Laser-mediated photostability (LMPS) assessment, Fourier-transform infrared spectra analysis acquired in attenuate total reflectance (ATR-FTIR), spectroscopy ellipsometry (SE), and time-resolved photoluminescence (TRPL) measurements under stress conditions prove that the inclusion of a thin β-carotene interlayer promotes a high improvement in the photostability of the perovskite films against photooxidation. Importantly, this is accompanied by an improvement of the solar cell PCE that approaches 20% efficiency with no hysteresis, which is among the highest values reported for a mixed halide (I-Br) perovskite with a band gap of 1.74 eV, relevant for coupling with silicon in tandem cells.

Dự báo tuổi thọ các hệ sơn bảo vệ kim loại khi sử dụng tại các khu vực khí hậu nhiệt đới Việt Nam

This paper presents the results of accelerated test of 8 commonly used metal protective paints under 2 modes of accelerated test simulating atmosphere at 2 testing stations of Joint Vietnam-Russia Tropical Science and Technology Research Center and by using previous test data of natural test as the basis for predicting service life. Corrosion protection parameter of paints is taken as a measure of service life. Acceleration testing and predicting methods are carried out according to the set of 3-standards GOST 15150-69, GOST 9.401-2018 and GOST 9.104-79 of the Russian Federation. Research shows that this set of 3-standards is a reliable tool to predict the service life of most metal protective coating systems working in tropical climate conditions in Vietnam (with error < 10%). The research results have high practical value and are guidelines for selecting paint suitable for conditions and use requirements.

On the Occurrence of Filiform Corrosion on Organic-Coated Carbon Steel Exposed to Cyclic Aging Test

Filiform corrosion (FFC) is one of the possible failure mechanisms of organic-coated steel. Beyond cathodic delamination, FFC causes paint detachment and the dramatic loss of the protective properties given by the applied paint. As both failure mechanisms occur during in-field exposure (depending on the environment), when assessing the performance of the protective paint by lab scale tests, we must be aware of the failure mechanism we induce with different accelerated aging cabinets. In this study, we investigate the effect of the prohesion test on the initiation and propagation of FFC. We highlight the concurrent development of FFC and cathodic blistering, which includes the change between the cathodic and anodic delamination front, during an accelerated aging procedure that cycles between saturated humidity and dry stages. The role of the presence of aggressive contaminants (Cl− and ) is discussed. According to our findings, cyclic aging tests seem to better stick to the failure mechanism occurring during in-field exposure, particularly due to the wet/dry cycles.

Shading Level and Harvest Time Affect the Photosynthetic and Physiological Properties of Basil Varieties

Basil (Ocimum basilicum L.) is one of the most important medicinal and aromatic plants. Light intensity is an indispensable factor for plants due to its effect on photosynthesis and physiological processes. Here, we investigated the impact of light intensities and harvesting times on the photosynthesis of green and purple basil. The experiment involved subjecting plants to three different levels of sunlight for 12 days: complete—100%, 50%, and 30%—sunlight. In addition, we evaluated the impact of harvest time during the day. The highest levels of photosynthetic and protective pigments were detected under full sunlight conditions in purple basil harvested at noon. The highest levels of soluble and storage carbohydrates were recorded in the purple basil grown under full sunlight and harvested during the early morning. By contrast, the lowest levels were obtained in plants grown under 30% sunlight and harvested at noon time. Under all light treatments, the maximum quantum yield of photosystem II (FV/FM) was detected at 4 a.m. in both basil varieties; it decreased at noon and increased again at 5 p.m. Non-Photochemical Quenching (NPQ) was most elevated in the green variety under all light intensities at noon. However, the highest NPQ was detected in the purple variety at 8 a.m. The NPQ was lowest in both basil varieties during the early morning and afternoon. Full sunlight at noon caused temporary photoinhibition and reduced carbohydrates while enhancing pigment concentration and photo-protective mechanisms in basil plants.

Chromate-free pigments for anti-corrosion protection of D16 aluminum alloy

Chromate-free pigments for anti-corrosion protection of D16 aluminum alloy