Hasil untuk "Paints, pigments, varnishes, etc."

Se-Ho Lee, Keunsoo Ko, Seung-Wook Kim

This paper presents a novel and efficient image enhancement method based on pigment representation. Unlike conventional methods where the color transformation is restricted to pre-defined color spaces like RGB, our method dynamically adapts to input content by transforming RGB colors into a high-dimensional feature space referred to as \textit{pigments}. The proposed pigment representation offers adaptability and expressiveness, achieving superior image enhancement performance. The proposed method involves transforming input RGB colors into high-dimensional pigments, which are then reprojected individually and blended to refine and aggregate the information of the colors in pigment spaces. Those pigments are then transformed back into RGB colors to generate an enhanced output image. The transformation and reprojection parameters are derived from the visual encoder which adaptively estimates such parameters based on the content in the input image. Extensive experimental results demonstrate the superior performance of the proposed method over state-of-the-art methods in image enhancement tasks, including image retouching and tone mapping, while maintaining relatively low computational complexity and small model size.

علیرضا طاهری مقدم, سمانه کاظم نژاد

گنبد سبز مشهد یکی از بناهای تاریخی دوره صفویه و تزیینات اصلی این آرامگاه شامل کاشی‌کاری‌های بیرونی متعلق به دوره پهلوی است. هدف از این پژوهش، شناسایی پالت رنگی کاشی‌کاری‌های گنبد سبز و تطبیق کمّی رنگ‌ها براساس سیستم رنگی NCS است. نظر به اهمیت و نقش محوری عنصر رنگ در هنر کاشی‌کاری ایرانی، این پژوهش در پی پاسخ به دو پرسش اساسی است: نخست آنکه معادل‌سازی کمّی پالت رنگی کاشی‌های بنای گنبد سبز براساس سیستم استاندارد رنگی NCS چیست؟ و دوم اینکه میزان فراوانی و قدرت رنگی در پالت کاشی‌کاری بنای گنبد سبز چگونه است و رنگ‌های غالب آن کدام هستند؟ روش گردآوری داده‌ها بر اساس مطالعات میدانی میدانی و از طریق انطباق سیستم رنگ NCS با کاشی‌های اصیل بنا است. در نتیجه تطبیق رنگ‌ها، ۱۲۲ کد رنگی از ۷ خانواده رنگی به دست آمد و با روش توصیفی-تحلیلی مورد بررسی و ارزیابی قرار گرفت. علاوه بر این، رنگ های غالب، قدرت رنگی و درصد تنوع رنگی نیز مشخص شد. نتایج نشان می‌دهد که هر چه رنگ‌ها روشن‌تر باشند، دامنه رنگی آن‌ها گسترده‌تر می‌شود و هر چه به سمت رنگ‌های تیره نزدیک می‌شویم، تنوع رنگی آن‌ها کاهش یافته و رنگ‌ها یکنواخت‌تر می‌شوند.

Heidi V. Kastenholz, Michael I. Topper, Warren S. Warren et al.

Carbon-based black pigments, a widely used class of pigments, are difficult to differentiate with the noninvasive techniques currently used in cultural heritage science. We utilize pump-probe microscopy to distinguish four common carbon-based black pigments as pure pigments, as two-component black pigment mixtures, and as a mixture of a black and a colorful pigment. This work also demonstrates that even nominally homogeneous pigments present remarkable, and useful, heterogeneity in pump-probe microscopy.

سحر آیار, حسن تاجیک, نیازمحمد محمودی et al.

در این تحقیق، چارچوب ایمیدازولات زئولیتی 67 (ZIF-67) و کامپوزیت زیستی کربوکسی متیل سلولز CMC/ZIF-67 (CMC/ZIF-67) سنتز شد. مواد سنتز‌شده با آنالیز‌های مختلف شناسایی شدند. سپس از کربوکسی متیل سلولز و کامپوزیت زیستی CMC/ZIF-67 برای حذف رنگزای مالاکیت گرین استفاده شد. نتایج نشان داد که قابلیت حذف رنگزا با کامپوزیت زیستی (35/92 درصد) بیشتر از پلیمر کربوکسی متیل سلولز (41/9 درصد) است. با افزایش مقدار جاذب، درصد حذف مالاکیت گرین نیز افزایش ‌‌می‌یابد. با افزایش مقدار جاذب، مکان‌های فعال سطح جاذب در دسترس‌‌‌تر‌ است و درصد حذف رنگزا بیشتر ‌‌می‌شود. درصد حذف رنگزا در مقادیر 1، 2، 3 و 4 میلی‌گرم جاذب کامپوزیت به ترتیب 25، 54، 79 و 35/92 درصد بود. با افزایش غلظت رنگزا، میزان حذف رنگزا کاهش یافت. میزان حذف رنگزا در غلظت‌های 20، 30، 40 و 50 میلی گرم در لیتر با کامپوزیت به ترتیب 35/92، 85، 79 و 71 درصد بود. وجود حلقه‌های ایمیدازول در ساختار ZIF-67 به عنوان لیگاند ‌‌می‌تواند یکی از دلایل اصلی ظرفیت جذب بالای کامپوزیت زیستی باشد. با توجه به پیوند‌های دوگانه در حلقه‌های ایمیدازول، برهم‌کنش‌های انباشتگی Π-Π با حلقه‌های آروماتیک مالاکیت گرین رخ ‌‌می‌دهد. این برهم‌کنش ویژه کامپوزیت زیستی را قادر می‌سازد تا ظرفیت بالای مالاکیت گرین را جذب کند. جذب رنگزا توسط کامپوزیت زیستی CMC/ZIF-67 از ایزوترم لانگمویر و سینتیک شبه مرتبه دوم پیروی ‌‌می‌کند.

مجید میرزایی, طیبه محبی

توسعه اخیر نیروگاه بادی دریایی (OWPDs) الزامات بالایی را برای مواد پوشش محافظ در برابر خوردگی و فرسایش ایجاد می‏کند. فرسایش لبه پیشرو (LE) پره‏های توربین بادی یکی از آسیب‏های رایج است که باعث کاهش تولید سالانه انرژی به ویژه در مزارع توربین بادی می‏شود. این فرسایش می‏تواند ناشی از باران، شن و ذرات جامد باشد.  همچنین قسمت‏های فلزی نیروگاه بادی دریایی در معرض محیط حاوی یون کلرید، دچار خوردگی حفره‏ای می‏شوند. پوشش‏های هیبریدی آلی- معدنی (OIHCs) به دلیل خواص برتر خود با ترکیب هر دو جزء معدنی و آلی مورد توجه بسیار زیادی قرار گرفته است. تکنیک سل-ژل روشی مناسب برای تولید پوشش‏های لایه نازک است که می‏تواند از اجزای نیروگاه بادی دریایی در برابر فرسایش و خوردگی محافظت کرده و در عین حال تأثیر ناچیزی بر وزن اجزای نیروگاه به خصوص پره‏های توربین داشته باشد. این مقاله مروری، استراتژی‏های اخیر برای پوشش‏های محافظ‌ OWPD‏ها را خلاصه می‏‏‏‏‏‏‏‏‏‏کند و چشم‏انداز توسعه OIHC‏ها را به عنوان مواد پوششی برای OWPD‏ها ارائه می‏دهد.

میلاد ادراکی, مژگان مهدیانی, میلاد شیدایی

خوردگی فلزات یک نگرانی جدی است که می‌تواند باعث آسیب اقتصادی شود. از دهه‌های گذشته استفاده از روش‌های مختلف برای جلوگیری از خوردگی استفاده می‌شود که در میان آنها استفاده از پوشش‌های پلیمری از ارجحیت خاصی برخوردار است. در میان پوشش‌ها، اپوکسی‌ها بسیار مورد توجه هستند، در حقیقت آنها در گروه رزین‌های گرماسخت قرار دارند و با انواع مختلفی از مواد پخت می‌شوند. آنها به‌دلیل خواص مکانیکی عالی، چسبندگی قوی برای بسیاری از بسترها، پایداری ابعادی و مقاومت حرارتی و شیمیایی بسیار مورد استفاده قرار می‌گیرند. برای بهبود خواص پوشش‌های اپوکسی می‌توان از نانوپرکننده‌ها استفاده کرد. در این میان گرافن و مکسین به‌دلیل خواص منحصر‌به‌فردی که دارند بسیار مورد توجه قرار گرفته‌اند. در این بررسی، به ‌سنتز گرافن و مکسین پرداخته می‌شود و همچنین استفاده از این دو نانو‌ذره در پوشش‌های اپوکسی مورد بررسی قرار گرفته است.

L. Frolova

Promising pigments of the passivating type, in addition to phosphate ones, are other materials - oxyhydroxides, ferrites, molybdates, stanates, borates, tungstates, which are obtained using traditional technologies. condition. Researchers are becoming increasingly interested in the co-precipitation method, which makes it possible to vary the cationic and anionic composition of pigments and obtain nanodispersed products. In addition, developers of paints and varnishes are faced with the task of replacing toxic anti-corrosion chromium-, cadmium- and plumbum-containing pigments that are part of most modern inhibitory primers with pigments that are safe for human health. An alternative to such paint and varnish materials are oxide type fillers, which are anti-corrosion pigments, including oxyhydroxides, magnesium ferrites, cobalt aluminates, zinc ferrites, copper ferrites, magnesium aluminates, zinc aluminates, etc. The color of pigments and their anticorrosion properties depend on the chromophore ions included in the structure of the resulting compounds. Co-precipitation technology has a number of advantages over traditional ones and can radically reduce the cost of producing oxide materials. This process, based on the use of the internal chemical energy of the system, allows synthesis to be carried out at reduced temperatures, synthesis duration and energy costs. The simplicity of the equipment, the possibility of synthesizing a significant amount of the product of the desired phase and granulometric composition, and the environmental friendliness of the process also indicate the feasibility of using this method. Recently, attempts have been made to obtain pigments by co-precipitation, but no systematic studies have been carried out on the final products. The resulting products were in most cases poorly reproducible. In this regard, it becomes interesting to synthesize in a mode that would make it possible to obtain pigments with good color characteristics in a finely dispersed state, and eliminate the labor-intensive grinding stage, study the conditions for the formation of pigments with the structure of oxyhydroxides, the influence of their composition on color and anti-corrosion properties, study the patterns of formation of anti-corrosion properties, development of compositions for producing pigments using the co-precipitation method and subsequent heat treatment. Through experimental and theoretical studies, the influence of the nature of chromophore cations on the color tone, color purity, and anti-corrosion properties of pigments in the Fe-Al-Mg-O system has been established, which allows for the targeted synthesis of beige, red and yellow pigments with high anti-corrosion properties. The main technological properties of pigments are determined by the composition of metal-containing anions. The anti-corrosion properties of oxyhydroxide pigments are largely determined by the presence of hydroxide ions formed due to dissociation. The greatest effect is observed in the case of using metal compounds whose dissociation constants differ significantly. The protective effect is mainly determined by the slowdown of the anodic process. At the same time, anions containing aluminum atoms accelerate corrosion processes.

L. Olshanskaya, E. N. Lazareva, E. Tatarintseva et al.

Galvanic production occupies one of the first places according to the degree of negative impact on the environment due to the content of heavy metal ions which have toxic, carcinogenic and mutagenic properties. Finding an effective method of recycling and utilization of galvanic sludge will solve the problem of the steady growth of the cost of metals and minimize the negative impact on the environment, which is an important environmental task of great scientific and practical significance. This paper presents the results of studies on the extraction of iron oxide(III) Fe2O3 from ironcontaining galvanic sludge to use it as a filler pigment in the manufacture of paint (red iron oxide). At the initial stage, the original galvanic sludge was dissolved in distilled water to a creamy consistency, and then, sulfuric acid was gradually added until the pH value gradually decreased (pH 6.0–1.5), metal sulfates were obtained. Iron hydroxide(III) Fe(OH)3 was precipitated from filtered sulfate solutions with 40% NaOH alkali solution at pH 1.5–4.1. After preliminary drying at a temperature of ≈ 150 оС, heat treatment was carried out at 600±2 оС for 5–6 h, obtaining iron oxide(III) Fe2O3, which met the requirements of GOST 10503-71 “Oil paints, ready to use. Technical Conditions in terms of particle size, oil capacity, particle density and pH of aqueous extracts. The iron minium paint made on its basis also met the requirements of this GOST on parameters: viscosity, hiding power, drying time, etc. A schematic diagram is proposed for obtaining a filler pigment used for the production of paints and varnishes. The scheme uses a set and layout of equipment widely used in industry (conveyor, batchers, screw feeders, acid and alkali treatment baths, centrifuge, drying and roasting oven).

Pablo Cencillo-Abad, Daniel Franklin, Pamela Mastranzo-Ortega et al.

All present commercial colors are based on pigments. While such traditional pigment-based colorants offer a commercial platform for large-volume and angle-insensitiveness, they are limited by their instability in the atmosphere, color fading, and severe environmental toxicity. Commercial exploitation of artificial structural coloration has fallen short due to the lack of design ideas and impractical nanofabrication techniques. Here, we present a self-assembled subwavelength plasmonic cavity that overcomes these challenges while offering a tailorable platform for rendering angle and polarization-independent vivid structural colors. Fabricated through large-scale techniques we produce stand-alone paints ready to be used on any substrate. The platform offers full coloration with a single layer of pigment, surface density of 0.4 g/m2, making it the lightest paint in the world.

L. Frolova, O. V. Sergeyeva

Zinc oxide has the subject of numerous studies in recent years. Nearly half of the world's annual production of zinc oxide is used as an activator to speed up vulcanization in the rubber industry. It is also widely used in pharmaceutical and cosmetic industries. It is most widely used in the chemical industry not only as a starting material, but also as a catalyst and chemisorbent. Recently, zinc oxide has been very often studied as an efficient photocatalyst in advanced oxidation processes. The cheapness and availability of zinc oxide makes it possible to use it also as a white pigment. White pigments make up more than 60% of all modern dyes. They are used for the manufacture of paints and varnishes not only white, but also other colors, as well as in the production of plastics, paper, building materials, ceramics, etc. Obtaining nanodispersed ZnO opens up additional possibilities for controlling its chemical and physical properties. Today, to obtain nanostructured ZnO, chemical deposition, synthesis in colloidal solutions, hydrothermal synthesis, laser vapor deposition, electrochemical deposition, thermal methods, electrochemical deposition, etc. are used. Promising technologies that make it possible to obtain disperse products are physicochemical methods, including those using contact nonequilibrium plasma (CNP). To form nanodispersed ZnO nanoparticles, we used CNP. This method is economically attractive due to the simplicity of the synthesis process (the temperature varies from room temperature to 50°C, the low cost of equipment and consumables) and the possibility of influencing the structural and morphological characteristics of NPs. Theoretical (Pourbaix diagrams) and experimental studies (cyclic voltammograms, potentiometry, kinetic dependences, X-ray phase analysis, derivatography, electron microscopy, spectroscopy) were carried out, which made it possible to establish the possibility of obtaining zinc oxide using CNP and investigate its properties. The results of X-ray diffraction analysis show that under these conditions, a precipitate of ZnO is formed. It was found that with an increase in rarefaction in the plasma-chemical reactor and a decrease in the interelectrode distance, an increase in the degree of conversion of zinc cations into insoluble compounds is observed. To increase the degree of conversion, the effect of organic compounds on the degree of conversion was also investigated. The addition of ethanol in the ratio 50-100 mmol/mol increases the product yield to 99.8% even in dilute solutions. Studies of color characteristics showed that the resulting precipitate has a CRC of 95%, a color purity value of 6%, and a color tone corresponding to a wavelength of 584 nm. The band gap was 3.1 eV.

Bingjie, Xu, Yunan Wu et al.

X-ray fluorescence spectroscopy (XRF) plays an important role for elemental analysis in a wide range of scientific fields, especially in cultural heritage. XRF imaging, which uses a raster scan to acquire spectra across artworks, provides the opportunity for spatial analysis of pigment distributions based on their elemental composition. However, conventional XRF-based pigment identification relies on time-consuming elemental mapping by expert interpretations of measured spectra. To reduce the reliance on manual work, recent studies have applied machine learning techniques to cluster similar XRF spectra in data analysis and to identify the most likely pigments. Nevertheless, it is still challenging for automatic pigment identification strategies to directly tackle the complex structure of real paintings, e.g. pigment mixtures and layered pigments. In addition, pixel-wise pigment identification based on XRF imaging remains an obstacle due to the high noise level compared with averaged spectra. Therefore, we developed a deep-learning-based end-to-end pigment identification framework to fully automate the pigment identification process. In particular, it offers high sensitivity to the underlying pigments and to the pigments with a low concentration, therefore enabling satisfying results in mapping the pigments based on single-pixel XRF spectrum. As case studies, we applied our framework to lab-prepared mock-up paintings and two 19th-century paintings: Paul Gauguin's Poèmes Barbares (1896) that contains layered pigments with an underlying painting, and Paul Cezanne's The Bathers (1899-1904). The pigment identification results demonstrated that our model achieved comparable results to the analysis by elemental mapping, suggesting the generalizability and stability of our model.

Théa de Seauve, Vincent Detalle, Alexandre Semerok et al.

Red lead and lead white are some of the most ancient and common pigments in mural paintings. However, they tend to blacken with time due to their oxidation to plattnerite (\b{eta}-PbO2). The possibility to induce the reconversion reactions by CW laser heating is hereby discussed. A thermodynamic study by TGA showed that direct cerussite or hydrocerussite formation from plattnerite are not suitable reconversion routes, which was confirmed by laser irradiation trials under CO2 and CO2/H2O fluxes. Minium (Pb3O4) and subsequent massicot (\b{eta}-PbO) formation from plattnerite were achieved (confirmed by SEM-EDS, XRD and micro-Raman) under Ar+, 810 nm diode and Nd:YAG lasers. The latter appears to be the most suited for restauration purposes, given the broad minium reconversion irradiance range. This is confirmed by successful trials on macroscopic areas of naturally darkened red lead containing samples.

Craig I. Hiley, Graeme M. Hansford, Nicholas Eastaugh

Energy-dispersive X-ray diffraction (EDXRD) is extremely insensitive to sample morphology when implemented in a back-reflection geometry. The capabilities of this non-invasive technique for cultural heritage applications have been explored at high resolution at the Diamond Light Source synchrotron. The results of the XRD analysis of the pigments in 40 paints, commonly used by 20th century artists, are reported here. It was found that synthetic organic pigments yielded weak diffraction patterns at best, and it was not possible to unambiguously identify any of these pigments. In contrast, the majority of the paints containing inorganic pigments yielded good diffraction patterns amenable to crystallographic analysis. The high resolution of the technique enables the extraction of a range of detailed information: phase identification (including solid solutions), highly accurate unit cell parameters, phase quantification, crystallite size and strain parameters and preferred orientation parameters. The implications of these results for application to real paintings are discussed, along with the possibility to transfer the technique away from the synchrotron and into the laboratory and museum through the use of state-of-the-art microcalorimeter detectors. The results presented demonstrate the exciting potential of the technique for art history and authentication studies, based on the non-invasive acquisition of very high quality crystallographic data.

Richard M. Parker, Tianheng H. Zhao, Bruno Frka-Petesic et al.

When pursuing sustainable approaches to fabricate photonic structures, nature can be used as a source of inspiration for both the nanoarchitecture and the constituent materials. Although several biomaterials have been promised as suitable candidates for photonic materials and pigments, their fabrication processes have been limited to the small to medium-scale production of films. Here, by employing a substrate-free process, structurally coloured microparticles are produced via the confined self-assembly of a cholesteric cellulose nanocrystal (CNC) suspension within emulsified microdroplets. Upon drying, the droplets undergo multiple buckling events, which allow for greater contraction of the nanostructure than predicted for a spherical geometry. This buckling, combined with a solvent or thermal post-treatment, enables the production of dispersions of vibrant red, green, and blue cellulose photonic pigments. The hierarchical structure of these pigments enables the deposition of coatings with angular independent colour, offering a consistent visual appearance across a wide range of viewing angles.