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

نسترن پارسافرد

این پژوهش عملکرد فوتوکاتالیزی کاتالیست دی اکسید تیتانیم/ اکسید آهن دوپ‌شده با لانتانیم در حذف فوتوکاتالیزی رنگزا‌های متیل رد، آلیزارین رد، متیلن بلو، متیل اورانژ و فنل فتالئین را بررسی می‌کند. این حذف فوتوکاتالیزی در شرایط مختلف از لحاظ اسیدیته محیط ( 11-3 pH=)، زمان انجام واکنش (min 0-35t= ) در دمای ثابت °C 45، غلظت رنگزای برابر با ppm 10 و 25/0 گرم کاتالیست انجام شد. نتایج نشان می‌دهد که فعالیت فوتوکاتالیزی به شدت به pH محلول و زمان واکنش بستگی دارد. برای بررسی اثرات هم‌زمان این دو عامل بر بازده‎ تخریب فوتوکاتالیزی از روش بهینه‌سازی سطح پاسخ استفاده شد. بهترین بازده‎ تخریب فوتوکاتالیزی برای رنگزای آلیزارین رد در 3 pH= و در زمان 35 دقیقه برابر با 77/93 درصد حاصل شد. یافته‌ها اثربخشی کاتالیست La/TiO2-Fe2O3 را در افزایش تخریب سایر رنگزاها (متیل رد (25/46 درصد)، متیلن بلو (37/42 درصد)، متیل اورانژ (03/11 درصد) و فنل فتالئین (84/57 درصد)) در 3 pH= نشان می‌دهد و بینش‌های ارزشمندی را برای بهینه‌سازی فرایند‎های فوتوکاتالیزی ارائه می‌کند.

Liliane Siqueira de Oliveira, Davi Vieira Teixeira da Silva, Lucileno Rodrigues da Trindade et al.

Food polysaccharides have emerged as suitable carriers of active substances and as additives to food and nutraceutical formulations, showing potential to stabilize bioactive compounds during the storage of microencapsulate preparations, even in the gastrointestinal tract following the intake of bioactive compounds, thereby improving their bioaccessibility and bioavailability. This review provides a comprehensive overview of the main polysaccharides employed as wall materials, including starch, maltodextrin, alginate, pectin, inulin, chitosan, and gum arabic, and discusses how structural interactions and physicochemical properties can benefit the microencapsulation of polyphenols and pigments. The main findings and principles of the major encapsulation techniques, including spray drying, freeze drying, extrusion, emulsification, and coacervation, related to the production of microparticles, were briefly described. Polysaccharides can entrap hydrophilic and hydrophobic compounds by physical interactions, forming a barrier around the nucleus or binding to the bioactive compound. Intermolecular binding between polysaccharides in the wall matrix, polyphenols, and pigments in the nucleus can confer up to 90% of encapsulation efficiency, governed mainly by hydrogen bonds and electrostatic interactions. The mixture of wall polysaccharides in the microparticles synthesis favors the encapsulation solubility, storage stability, bioaccessibility, and bioactivity of the microencapsulate compounds. Clinical trials on the bioefficacy of polyphenols and pigments loaded in polysaccharide microparticles are scarce and require further evidence to reinforce the use of this technology.

Angshu Adhya, Cindy Yang, Emily Wu et al.

In this work we present AURA, a framework for synergistic human-artist painting. We developed a robot arm that collaboratively paints with a human artist. The robot has an awareness of the artist's heartbeat through the EmotiBit sensor, which provides the arousal levels of the painter. Given the heartbeat detected, the robot decides to increase proximity to the artist's workspace or retract. If a higher heartbeat is detected, which is associated with increased arousal in human artists, the robot will move away from that area of the canvas. If the artist's heart rate is detected as neutral, indicating the human artist's baseline state, the robot will continue its painting actions across the entire canvas. We also demonstrate and propose alternative robot-artist interactions using natural language and physical touch. This work combines the biometrics of a human artist to inform fluent artistic interactions.

مهدیه قمری, مرضیه صالحی

امروزه استفاده از مواد رنگزا طبیعی در صنایع غذایی و دارویی بسیار حائز اهمیت است. مواد رنگزا طبیعی به دست آمده از حیوانات، گیاهان و میکروارگانیسم‌ها جایگزین امیدوارکننده‌ای برای مواد رنگزا خوراکی مصنوعی هستند زیرا مواد رنگزا سنتتیک در دراز مدت تاثیر منفی بر سلامت انسان دارد. فیکوسیانین به عنوان یک ماده رنگزا طبیعی آبی و محلول در آب به جای مواد‌ رنگزا خوراکی آبی مصنوعی استفاده می‌شود که علاوه بر رنگ دادن به غذا، خواص مفید بالقوه‌ای به عنوان آنتی‌اکسیدان‌ها و عوامل ضدسرطانی نیز داشته و از این رو مورد توجه علمی و صنعتی قرار گرفته‌اند. فیکوسیانین از ریزجلبک ها مانند اسپیرولینا استخراج می‌گردد و نقش سلامت بخش در برابر شرایط مختلف مانند سرطان، کم خونی، التهاب، دیابت، چاقی و اختلالات عصبی دارد و به دلیل کاربردهای متنوع در صنایع مختلف غذایی و دارویی محبوبیت پیدا کرده است. در این تحقیق مروری بر تولید بیوتکنولوژیکی ماده رنگزا آبی خوراکی فیکوسیانین از ریزجلبک اسپیرولینا، کشت میکروبی، استخراج، خالص‌سازی، روش‌های پایداری و کاربردهای آن پرداخته شده است.

Lasantha Thakshila Wedage, Mehmet Can Vuran, Bernard Butler et al.

This work opens a new chapter in the 100,000 year-old concept of paint, by leveraging innovations in nano-technology in the sub-THz frequency range. More specifically, the groundbreaking concept of Internet of Paint (IoP) is introduced along with a comprehensive channel model and a capacity analysis for nano-scale radios embedded in paint and communicating through paint. Nano-network devices, integrated within a paint medium, communicate via a multipath strategy, encompassing direct waves, reflections from interfaces, and lateral wave propagation. The evaluation incorporates three distinct paint types to assess path losses, received powers, and channel capacity. Analysis of path loss indicates a slight non-linear increase with both frequency and Line of Sight (LoS) distance between transceivers. Notably, paints with high refractive indexes result in the highest path loss. Moreover, burying transceivers at similar depths near the Air-Paint interface showcases promising performance of lateral waves with increasing LoS distance. Increasing paint layer depth leads to amplified attenuation, while total received power exhibits promising results when in close proximity to the Air-Paint interface but steeply declines with burial depth. Additionally, a substantial reduction in channel capacity is observed with LoS distance and burial depth, so transceivers need to be close together and in proximity of the A-P interface to communicate effectively. Comparing paint and air mediums, IoP demonstrates approximately two orders of magnitude reduction in channel capacity compared to air-based communication channels. This paper provides valuable insights into the potential of IoP communication within paint mediums and offers a foundation for further advancements in this emerging field.

Yue Zhou, David Grass, Warren S. Warren et al.

Cadmium sulfide (CdS) pigments have degraded in several well-known paintings, but the mechanisms of degradation have yet to be fully understood. Traditional non-destructive analysis techniques primarily focus on macroscopic degradation, whereas microscopic information is typically obtained with invasive techniques that require sample removal. Here, we demonstrate the use of pump-probe microscopy to nondestructively visualize the three-dimensional structure and degradation progress of CdS pigments in oil paints. CdS pigments, reproduced following historical synthesis methods, were artificially aged by exposure to high relative humidity (RH) and ultraviolet (UV) light. Pump-probe microscopy was applied to track the degradation progress in single grains, and volumetric imaging revealed early CdS degradation of small particles and on the surface of large particles. This indicates that the particle dimension influences the extent and evolution of degradation of historical CdS. In addition, the pump-probe signal decrease in degraded CdS is observable before visible changes to the eye, demonstrating that pump-probe microscopy is a promising tool to detect early-stage degradation in artworks. The observed degradation by pump-probe microscopy occurred through the conversion from CdS into CdSO4.xH2O, verified by both FTIR (Fourier-transform infrared) and XPS (X-ray photoelectron spectroscopy) experiment.

Tianqi Sai, Luis S. Froufe-Pérez, Frank Scheffold et al.

Color can originate from wavelength-dependence in the absorption of pigments or the scattering of nanostructures. While synthetic colors are dominated by the former, vivid structural colors found in nature have inspired much research on the latter. However, many of the most vibrant colors in nature involve the interactions of structure and pigment. Here, we demonstrate that pigment can be exploited to efficiently create bright structural color at wavelengths outside its absorption band. We created pigment-enhanced Bragg reflectors by sequentially spin-coating layers of poly-vinyl alcohol (PVA) and polystyrene (PS) loaded with $β$-carotene (BC). With only 10 double layers, we acheived a peak reflectance over $0.8$ at 550 nm and normal incidence. A pigment-free multilayer made of the same materials would require 25 double layers to achieve the same reflectance. Further, pigment loading suppressed the Bragg reflector's characteristic iridescence. Using numerical simulations, we further show that similar pigment loadings could significantly expand the gamut of non-iridescent colors addressable by photonic glasses.

James Lee Wei Shung, Paul Hibbard, Roshan Vijay et al.

LiDAR (Light Detection and Ranging) is a useful sensing technique and an important source of data for autonomous vehicles (AVs). In this publication we present the results of a study undertaken to understand the impact of automotive paint on LiDAR performance along with a methodology used to conduct this study. Our approach consists of evaluating the average reflected intensity output by different LiDAR sensor models when tested with different types of automotive paints. The paints were chosen to represent common paints found on vehicles in Singapore. The experiments were conducted with LiDAR sensors commonly used by autonomous vehicle (AV) developers and OEMs. The paints used were also selected based on those observed in real-world conditions. This stems from a desire to model real-world performance of actual sensing systems when exposed to the physical world. The goal is then to inform regulators of AVs in Singapore of the impact of automotive paint on LiDAR performance, so that they can determine testing standards and specifications which will better reflect real-world performance and also better assess the adequacy of LiDAR systems installed for local AV operations. The tests were conducted for a combination of 13 different paint panels and 3 LiDAR sensors. In general, it was observed that darker coloured paints have lower reflection intensity whereas lighter coloured paints exhibited higher intensity values.

Deepan Balakrishnan, Anupama Prakash, Benedikt J. Daurer et al.

How pigment distribution influences the cuticle density within a microscopic butterfly wing scale, and how both impact each scale's final reflected color, remains unknown. We use ptychographic X-ray computed tomography to quantitatively determine, at nanoscale resolutions, the three-dimensional mass density of scales with pigmentation differences. By comparing cuticle densities between two pairs of scales with pigmentation differences, we determine that the density of the lower lamina is inversely correlated with pigmentation. In the upper lamina structure of Junonia orithya and Bicyclus anynana, low pigment levels also correlate with sheet-like chitin structures as opposed to rod-like structures. Within each scale, we determine that the lower lamina in all scales has the highest density, and distinct layers within the lower lamina help explain reflected color. We hypothesize that pigments, in addition to absorbing specific wavelengths, can affect cuticle polymerization, density, and refractive index, thereby impacting reflected wavelengths that produce colors.

Teng Hu, Ran Yi, Haokun Zhu et al.

Stroke-based rendering aims to recreate an image with a set of strokes. Most existing methods render complex images using an uniform-block-dividing strategy, which leads to boundary inconsistency artifacts. To solve the problem, we propose Compositional Neural Painter, a novel stroke-based rendering framework which dynamically predicts the next painting region based on the current canvas, instead of dividing the image plane uniformly into painting regions. We start from an empty canvas and divide the painting process into several steps. At each step, a compositor network trained with a phasic RL strategy first predicts the next painting region, then a painter network trained with a WGAN discriminator predicts stroke parameters, and a stroke renderer paints the strokes onto the painting region of the current canvas. Moreover, we extend our method to stroke-based style transfer with a novel differentiable distance transform loss, which helps preserve the structure of the input image during stroke-based stylization. Extensive experiments show our model outperforms the existing models in both stroke-based neural painting and stroke-based stylization. Code is available at https://github.com/sjtuplayer/Compositional_Neural_Painter

الهه شریفی, سارا خمسه, امیرسعید شیرانی et al.

طول عمر و کارایی تجهیزات صنعتی، عمدتاً به ساختار و نحوه عملکرد آنها در محیط‌های مهاجم وابسته است. به همین منظور، حفاظت از سطح تجهیزات از اهمیت بالایی برخوردار است. در دهه‌‌‌های اخیر،‌ پوشش‌های سخت چند‌جزئی به شدت مورد توجه جوامع علمی و صنعتی قرار گرفته است. تاکنون، انواع مختلفی از پوشش‌های چند جزئی بر پایه فلزات واسطه، همچون کرم، تیتانیم و فلزات واسطه دیرگداز، به طور گسترده برای استفاده به عنوان پوشش‌های محافظ مورد استفاده قرار گرفته‌اند. با این حال، دیگر اجزای تشکیل‌دهنده پوشش‌های بر پایه فلزات مذکور (به عنوان مثال کربن، نیتروژن و سیلیکون)، ریخت‌شناسی سطح و اندازه دانه‌ها، نقش بسیار مهمی در خواص و کاربرد آنها خواهد داشت. به عنوان مثال پوشش‌های دو جزئی نیتریدی نمی‌توانند عملکرد خوبی در شرایط سایشی داشته باشند، در حالی‌که پوشش‌های دو جزئی کاربیدی کاندید‌های قابل‌توجهی برای این شرایط هستند. با این حال، پوشش‌های نازک سه‌جزئی کربو نیترید، می‌توانند خواص مکانیکی و عملکرد سایشی و اصطکاک بهتری را نسبت به پوشش‌های دو جزئی ارائه دهند. از سوی دیگر، برخی از خواص پوشش‌های مبتنی بر فلزات واسطه مانند مقاومت در برابر اکسیدشدن، تنش پسماند و عملکرد اصطکاکی را می‌توان با دوپ‌کردن سیلیکون (Si) به میزان قابل‌توجهی بهبود بخشید.

Abu Md Niamul Taufique, David W. Messinger

Kubelka-Munk (K-M) theory has been successfully used to estimate pigment concentrations in the pigment mixtures of modern paintings in spectral imagery. In this study the single-constant K-M theory has been utilized for the classification of green pigments in the Selden Map of China, a navigational map of the South China Sea likely created in the early seventeenth century. Hyperspectral data of the map was collected at the Bodleian Library, University of Oxford, and can be used to estimate the pigment diversity, and spatial distribution, within the map. This work seeks to assess the utility of analyzing the data in the K/S space from Kubelka-Munk theory, as opposed to the traditional reflectance domain. We estimate the dimensionality of the data and extract endmembers in the reflectance domain. Then we perform linear unmixing to estimate abundances in the K/S space, and following Bai, et al. (2017), we perform a classification in the abundance space. Finally, due to the lack of ground truth labels, the classification accuracy was estimated by computing the mean spectrum of each class as the representative signature of that class, and calculating the root mean squared error with all the pixels in that class to create a spatial representation of the error. This highlights both the magnitude of, and any spatial pattern in, the errors, indicating if a particular pigment is not well modeled in this approach.

Owen R. Lehmer, David C. Catling, Mary N. Parenteau et al.

In the search for life on other planets, the presence of photosynthetic vegetation may be detectable from the colors of light it reflects. On the modern Earth, this spectral reflectance is characterized by an increase in reflectance between the red and near-infrared wavelengths, a "red edge". On planets orbiting different stellar types, red edge analogs may occur at other colors than red. Thus, knowing the wavelengths at which photosynthetic organisms preferentially absorb and reflect photons is necessary to detect red edge analogs on other planets. Using a numerical model that predicts the absorbance spectrum of extant photosynthetic pigments on Earth from Marosvölgyi and van Gorkom (2010), we calculate the absorbance spectrum for pigments on an Earth-like planet around F through late M type stars that are adapted for maximal energy production. In this model, cellular energy production is maximized when pigments are tuned to absorb at the wavelength that maximizes energy input from incident photons while minimizing thermal emission and costs to build the photosynthetic apparatus. We find that peak photon absorption for photosynthetic organisms around F type stars tends to be in the blue while for G, K, and early M type stars, red or just beyond is preferred. Around the coolest M type stars, these organisms may preferentially absorb in the near-infrared, possibly past one micron. These predictions are consistent with previous, qualitative estimates of pigment absorptance. Our predicted pigment absorbance spectra depend on both the stellar type and planetary atmospheric composition, especially atmospheric water vapor concentrations, which alter the availability of surface photons and thus the predicted pigment absorption. By constraining the absorbance spectra of alien, photosynthetic organisms, future observations may be better equipped to detect red edge analogs.

Saichao Dang, Jingbo Xiang, Hongxin Yao et al.

Materials with both low absorption of incoming solar radiation and high emittance in mid-infrared band can be applied for daytime radiative cooling. Current state-of-the-art materials for passive radiative cooling often utilize a combination of solar reflector and infrared emitter by different structures, or even by expensive nanofabricated photonic structures, which limits the applications in practice. In this study, possessing these two specified radiative properties, pure Y2Ce2O7 is demonstrated with a performance of passive radiative cooling. With a bandgap at 375.7 nm, the prepared Y2Ce2O7 shows a high solar reflectance of 91%, while with lattice strain and distortion of various bonds (e.g., Y-O, Ce-O), it also shows a high emittance of 0.96 in MIR band. More attracting, the aesthetics performance of Y2Ce2O7 can be modified by doping Fe3+ ions to change its color from ivory white to light yellow or red with high NIR reflection and MIR emission, indicating that the Y2Ce2-xFexO7 shows a better cooling performance than a common paint with a similar color. According to the field demonstration of cooling performance at noon time, the Y2Ce2O7 and Y2Ce1.9Fe0.1O7 paints are 2.2 K and 1.8 K lower than the common white and umber paints, respectively, while at night, all paints are 2.3 K lower than the ambient air. If applied on the envelop of a building, the simulation shows that the Y2Ce2O7 and Y2Ce1.9Fe0.1O7 paints save 54.45% and 21.14% energy consumption compared with a common white and umber paints, respectively, in a hot season. The demonstrated Y2Ce2-xFexO7 holds potentials for energy-saving applications in hot climates.