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

Masaaki Tsubouchi, Takatoshi Fujita, Motoyasu Adachi et al.

We developed methods for protein synthesis and performed two-dimensional electronic spectroscopy (2D-ES) to examine the influence of pigment arrangement on the photoexcitation dynamics of light-harvesting proteins in phycobilisome. We synthesized allophycocyanin (APC), C-phycocyanin (CPC), and mutant CPC lacking the \b{eta}153 phycocyanobilin (PCB) pigment by an Escherichia coli expression system. The number of pigments in the mutant CPC is identical to that in the wild-type APC, and their spatial arrangements are similar. The absorption and fluorescence spectra of the mutant CPC closely resemble those of the wild-type CPC rather than the wild-type APC, indicating that pigment spatial arrangement is not a primary factor in determining the excited-state energy structure. The 2D-ES measurements show that the wild-type CPC retains broad positive signals at 1 ps, signifying incomplete relaxation and persistence of excited vibronic states, unlike APC, which vibrationally relaxes to the bottom of the potential energy surface within the same timeframe. The mutant CPC behaves similarly to the wild-type CPC in the 2D-ES, reinforcing that the pigment number or arrangement is not a dominant factor. Instead, the local pigment-protein interaction governs the electronic structure and relaxation dynamics. Structural analysis reveals that the bent structure of PCB in CPC's α-chain versus the planar structure of PCB in APC. The bent PCB in CPC reduces the degree of π-conjugation, and exhibits excited-state properties distinct from those of the planar structure of PCB in APC. This finding highlights a critical role of the electronic structure governed by the local interaction in ultrafast energy relaxation.

Pranali Roy Chowdhury, Tian Xu Wang, Abbey MacDonald et al.

Pigmentation abnormalities, ranging from hypo- to hyperpigmentation, can serve as biomarkers of developmental disruption in fish exposed to environmental contaminants. However, the mechanistic pathways underlying these alterations remain poorly understood. Studies have shown that pattern formation in fish development requires specific pigment cell interactions. Motivated by experimental observations of pigmentation alterations following contaminant exposure, we investigate how pollutants influence pigment cell self-organization using a continuum reaction-diffusion-advection framework. The model incorporates nonlocal Morse-type kernels to describe short- and long-range interactions among melanophores and xanthophores. Our results show that perturbations to the strengths of adhesion or repulsion can drive transitions between stripes, spots, and mixed patterns, reproducing phenotypes characteristic of fish pigmentation mutants. In particular, homotypic interactions are sensitive to contamination, leading to pronounced changes in melanophore density and resulting pigmentation patterns. Time-dependent simulations indicate that pigment changes from early short-term contaminant exposure may be recoverable, whereas prolonged exposure can lead to sustained pigment loss. In a growing fish, contaminant-induced changes in cell-cell interactions directly influence stripe formation rate, stripe number, and pigmentation levels. Overall, our study provides insight into the mechanistic link between experimentally observed pigmentation alterations and the changes in spatial patterns of adult fish.

Hao Gong, Michel Desvignes

Decomposition of skin pigment plays an important role in medical fields. Human skin can be decomposed into two primitive components, hemoglobin and melanin. It is our goal to apply these results for diagnosis of skin cancer. In this paper, various methods for skin pigment decomposition are reviewed comparatively and the performance of each method is evaluated both theoretically and experimentally. In addition, isometric feature mapping (Isomap) is introduced in order to improve the dimensionality reduction performance in context of skin pigment decomposition.

Bowei Chen, Yifan Wang, Brian Curless et al.

Given an input painting, we reconstruct a time-lapse video of how it may have been painted. We formulate this as an autoregressive image generation problem, in which an initially blank "canvas" is iteratively updated. The model learns from real artists by training on many painting videos. Our approach incorporates text and region understanding to define a set of painting "instructions" and updates the canvas with a novel diffusion-based renderer. The method extrapolates beyond the limited, acrylic style paintings on which it has been trained, showing plausible results for a wide range of artistic styles and genres.

Bhrigu Rishi Mishra, Sreerag Sundaram, Karthik Sasihithlu

Recent developments in radiative cooling technologies have primarily focused on affordable paint coatings that are easy to fabricate and deploy. Using a systematic approach to obtain optimal parameters, a radiative cooling (RC) paint coating using titanium dioxide (TiO2) and polydimethylsiloxane (PDMS) is designed. The resulting paint exhibits a high solar reflectivity of 88.2 % (more than 94% in visible and NIR) and an emissivity of 92.4 %. Outdoor testing demonstrates a maximum reduction of 7.9 0C in the internal temperature of an RC paint-coated aluminium (Al) box compared to a bare Al box but in contrast to other studies, no sub-ambient cooling have been observed. In this context, a comprehensive analysis explaining the absence of sub-ambient cooling and underscore the importance of a standardized reporting methodology for RC paints has been discussed. Theoretical calculations suggest that the developed RC paint can achieve sub-ambient cooling (1-4 0C) under specific ambient conditions.

اخترالسادات موسوی, ایمان زکریایی کرمانی, علی حاجی غلام سریزدی

رنگرزی طبیعی جز جدایی‌‌ناپذیر فرش دستباف ایرانی از گذشته دور تا به امروز بوده است. اخیرا علاقمندی مجدد به استفاده از رنگزاهای طبیعی در رنگرزی منسوجات گسترش یافته است. در این راستا هدف از این پژوهش ارائه یک مدل پویا جهت توسعه فناوری استفاده از رنگزاهای طبیعی در صنعت فرش دستباف است. لذا در تحقیق حاضر با استفاده از رویکرد پویایی‌‌‌‌شناسی کیفی ‌‌سیستم و ترسیم نمودارهای علی حلقوی، متغیرهای تأثیرگذار بر توسعه فناوری استفاده از رنگزاهای طبیعی در صنعت فرش دستباف شناسایی شده و در نهایت با ایجاد یک مدل مفهومی عوامل و روابط بین متغیرهای تحقیق نشان داده شده است. نتایج نشان می‌دهد ارتباط پژوهشگاه‌ها و صنعت فرش دستباف در نهایت باعث بهره‌وری و سودآوری بازار فرش دستباف خواهد شد که همین امر تمایل بازار را جهت توسعه فناوری استفاده از رنگزاهای طبیعی در صنعت فرش دستباف افزایش خواهد داد.

Penghui Shen, Mouming Zhao, Jasper Landman et al.

Protein-inorganic hybrid nanoflowers (HNFs) possess unique properties in promoting surface reaction and have attracted wide-spread attention as a newly developed nanomaterial. However, the availability of protein sources has up to now been mostly limited to enzymes, which narrows the application of HNFs especially in food industry. Here we show that for many types of food protein, enzymatic hydrolysis can improve its ability to form versatile HNFs, or even induce HNF formation where the protein source did not show its formation a priori. The treatment of enzymatic hydrolysis increases the flexibility of such proteins and induces nucleation sites of HNFs in the early formation stage by decomposing those proteins into polypeptides. In particular, the HNF prepared with soy protein hydrolysate further shows a high loading capacity of water-soluble Monascus red, reaching up to 554.1 mg per gram of HNF. Its stabilization towards lipophilic curcumin is similarly impressive with the loading capacity reaching 21.9 mg per gram of HNF. This HNF could also effectively protect these two sensitive natural pigments in harsh environments. This research significantly broadens the available protein source for HNF fabrication and demonstrates the potential of HNFs as novel protein-based delivery systems - especially for sensitive natural pigments - which could serve the fields of food, cosmetic and medicine.

Debra Boutin

You are handed a graph with vertices in a neutral color and asked to color a subset of vertices with expensive paints in $d$ colors in such a way that only the trivial symmetry preserves the color classes. Your goal is to minimize the number of vertices needing this expensive paint. This paper address the issues surrounding your choices. In particular, a graph is said to be $d$-distinguishable if there exists a coloring with $d$ colors so that only the trivial automorphism preserves the color classes. The distinguishing number of $G$, denoted ${\rm Dist}(G)$, is the smallest $d$ for which $G$ is $d$-distinguishable. We define the -paint cost of $d$-distinguishing, denoted $ρ^d(G)$, to be the minimum number of vertices that need to be painted to $d$-distinguish $G$. This cost varies with $d$. The maximum paint cost for $G$ is called the upper paint cost, denoted $ρ^u(G)$, and occurs when $d={\rm Dist}(G)$; the minimum paint cost is called the lower paint cost, denoted $ρ^\ell(G)$. Further, we define the smallest $d$ for which the paint cost is $ρ^\ell(G)$, to be the frugal distinguishing number, ${\rm Fdist}(G)$. In this paper we formally define $ρ^d(G)$, $ρ^u(G)$, $ρ^\ell(G)$, and ${\rm Fdist}(G)$. We also show that $ρ^u(G)$ and $ρ^\ell(G)$, as well as ${\rm Fdist}(G)$ and ${\rm Dist}(G)$, can be arbitrarily large multiples of each other. Lastly, we find these parameters for the book graph $B_{m,n}$, summarized as follows. For $n\geq 2$ and $m\geq 4$, we show $\bullet$ $ρ^\ell(B_{m,n}) = n-1;$ $\bullet$ $ρ^u(B_{m,n}) \geq (m-2) \left( n-k^{m-3} \right) +1$, where $k={\rm Dist}(B_{m,n});$ $\bullet$ ${\rm Fdist}(B_{m,n}) = 2+\left\lfloor \frac{n-1}{m-2} \right\rfloor.$

Jaskirat Singh, Cameron Smith, Jose Echevarria et al.

The generation of well-designed artwork is often quite time-consuming and assumes a high degree of proficiency on part of the human painter. In order to facilitate the human painting process, substantial research efforts have been made on teaching machines how to "paint like a human", and then using the trained agent as a painting assistant tool for human users. However, current research in this direction is often reliant on a progressive grid-based division strategy wherein the agent divides the overall image into successively finer grids, and then proceeds to paint each of them in parallel. This inevitably leads to artificial painting sequences which are not easily intelligible to human users. To address this, we propose a novel painting approach which learns to generate output canvases while exhibiting a more human-like painting style. The proposed painting pipeline Intelli-Paint consists of 1) a progressive layering strategy which allows the agent to first paint a natural background scene representation before adding in each of the foreground objects in a progressive fashion. 2) We also introduce a novel sequential brushstroke guidance strategy which helps the painting agent to shift its attention between different image regions in a semantic-aware manner. 3) Finally, we propose a brushstroke regularization strategy which allows for ~60-80% reduction in the total number of required brushstrokes without any perceivable differences in the quality of the generated canvases. Through both quantitative and qualitative results, we show that the resulting agents not only show enhanced efficiency in output canvas generation but also exhibit a more natural-looking painting style which would better assist human users express their ideas through digital artwork.

Fatemeh Ghasemi, Afshin Shafiee

Despite several different measures of efficiency that are applicable to the photosynthetic systems, a precise degree of efficiency of these systems is not completely determined. Introducing an efficient model for the dynamics of light-harvesting complexes in biological environments is a major purpose in investigating such systems. Here, we investigate the effect of macroscopic quantum behavior of a system of two pigments on the transport phenomena in this system model which interacts with an oscillating environment. We use the second-order perturbation theory to calculate the time-dependent population of excitonic states of a two-dimensional Hamiltonian using a non-master equation approach. Our results demonstrate that the quantum efficiency is robust with respect to the macroscopicity parameter h solely, but the ratio of macroscopicity over the pigment-pigment interaction energy can be considered as a parameter that may control the energy transfer efficiency at a given time. So, the dynamical behavior and the quantum efficiency of the supposed photosynthetic system may be influenced by a change in the macroscopic behavior of the system.

Xiangyu Li, Joseph Peoples, Peiyan Yao et al.

Radiative cooling is a passive cooling technology that offers great promises to reduce space cooling cost, combat the urban island effect and alleviate the global warming. To achieve passive daytime radiative cooling, current state-of-the-art solutions often utilize complicated multilayer structures or a reflective metal layer, limiting their applications in many fields. Attempts have been made to achieve passive daytime radiative cooling with single-layer paints, but they often require a thick coating or show partial daytime cooling. In this work, we experimentally demonstrate remarkable full daytime sub-ambient cooling performance with both BaSO4 nanoparticle films and BaSO4 nanocomposite paints. BaSO4 has a high electron bandgap for low solar absorptance and phonon resonance at 9 um for high sky window emissivity. With an appropriate particle size and a broad particle size distribution, BaSO4 nanoparticle film reaches an ultra-high solar reflectance of 97.6% and high sky window emissivity of 0.96. During field tests, BaSO4 film stays more than 4.5C below ambient temperature or achieves average cooling power of 117 W/m2. BaSO4-acrylic paint is developed with 60% volume concentration to enhance the reliability in outdoor applications, achieving solar reflectance of 98.1% and sky window emissivity of 0.95. Field tests indicate similar cooling performance to the BaSO4 films. Overall, our BaSO4-acrylic paint shows standard figure of merit of 0.77 which is among the highest of radiative cooling solutions, while providing great reliability, the convenient paint form, ease of use and the compatibility with commercial paint fabrication process.

Zachary Mulhollan, Aneesh Rangnekar, Timothy Bauch et al.

We investigate a procedure for rapidly adding calibrated vehicle visible-near infrared (VNIR) paint signatures to an existing hyperspectral simulator - The Digital Imaging and Remote Sensing Image Generation (DIRSIG) model - to create more diversity in simulated urban scenes. The DIRSIG model can produce synthetic hyperspectral imagery with user-specified geometry, atmospheric conditions, and ground target spectra. To render an object pixel's spectral signature, DIRSIG uses a large database of reflectance curves for the corresponding object material and a bidirectional reflectance model to introduce s due to orientation and surface structure. However, this database contains only a few spectral curves for vehicle paints and generates new paint signatures by combining these curves internally. In this paper we demonstrate a method to rapidly generate multiple paint spectra, flying a drone carrying a pushbroom hyperspectral camera to image a university parking lot. We then process the images to convert them from the digital count space to spectral reflectance without the need of calibration panels in the scene, and port the paint signatures into DIRSIG for successful integration into the newly rendered sets of synthetic VNIR hyperspectral scenes.

Prerna Kashyap, Samrat Phatale, Iddo Drori

Painting captions are often dry and simplistic which motivates us to describe a painting creatively in the style of Shakespearean prose. This is a difficult problem, since there does not exist a large supervised dataset from paintings to Shakespearean prose. Our solution is to use an intermediate English poem description of the painting and then apply language style transfer which results in Shakespearean prose describing the painting. We rate our results by human evaluation on a Likert scale, and evaluate the quality of language style transfer using BLEU score as a function of prose length. We demonstrate the applicability and limitations of our approach by generating Shakespearean prose for famous paintings. We make our models and code publicly available.

Mahsa Yazdani, Omid Tavakoli

Dunaliella Salina is a halotolerant microalga with great pharmaceutical and industrial potential, which commonly exists in hypersaline environments. Moreover, it is the best commercial source of beta-carotene (which has high anti-oxidant properties) in comparison to other microalgae. In this study, we investigated growth and accumulations of chlorophyll a and b, beta-carotene, and carotenoid after salt shock in 1, 1.5, 2, 2.5, 3 M concentrations of NaCl. The highest cell growth rate was observed in 1 M salt shock at 22-25 centigrade with a light intensity of 2.084 (mW.cm)^(-2), a light period of 12-12, and at an initial pH of about 7.1. Although the cell growth was enhanced in 1 and 1.5M, further increase in salt content harmed cell growth. The most considerable beta-carotene quantity was attained after 1M salt shock. According to the experimental observations, it was seen that the salt shock in some concentrations is one of the practical approaches to improve the accumulation of pigments. Keywords: beta-carotene, Dunaliella salina, salt shock, pigment accumulation.

Tingting Qiao, Weijing Zhang, Miao Zhang et al.

Collecting a large-scale and well-annotated dataset for image processing has become a common practice in computer vision. However, in the ancient painting area, this task is not practical as the number of paintings is limited and their style is greatly diverse. We, therefore, propose a novel solution for the problems that come with ancient painting processing. This is to use domain transfer to convert ancient paintings to photo-realistic natural images. By doing so, the ancient painting processing problems become natural image processing problems and models trained on natural images can be directly applied to the transferred paintings. Specifically, we focus on Chinese ancient flower, bird and landscape paintings in this work. A novel Domain Style Transfer Network (DSTN) is proposed to transfer ancient paintings to natural images which employ a compound loss to ensure that the transferred paintings still maintain the color composition and content of the input paintings. The experiment results show that the transferred paintings generated by the DSTN have a better performance in both the human perceptual test and other image processing tasks than other state-of-art methods, indicating the authenticity of the transferred paintings and the superiority of the proposed method.