نشریه مطالعات در دنیای رنگ
سال یازدهم شماره 1 (پیاپی 40، بهار 1400)

Evolution has been optimizing proteins for light reception and energy conversion for more than 3.5 billion years. The use of genetic engineering and bio-dyes has provided an array of new materials that have enhanced properties. Dye-sensitized solar cells based on bio-photosensitizers (bio-sensitized DSSCs) are promising bio-photoelectronic devices for electrical energy preparation. In this paper, a comprehensive study was presented on the mechanisms involved in the utilization of bio-dyes for an improved bio-sensitized DSSCs performance. Protein complexes, and chlorophyll a and carotenoids are among many bio-photosensitizers demonstrating high incident photon-to-current efficiency (IPCE). Like other sensitizers, the band- gap is an important factor in final performance of the optical component. Theoretical-average HOMO-to-LUMO band-gaps of 2.46, 5.22, 4.13, 1.13, 3.15, and 2.22 eV were calculated for anthocyanin, carotenoid, chlorophyll, cyanine, xanthene, and coumarin, respectively. It is more probable that low dye band-gaps result in enhanced HOMO-electron excitation and e-h pair generation. The highest conversion efficiency for bio-DSSCs based on PPB+Spx is about 4%. 

Polyurethanes are one of the most important multifunctional polymers that are widely used in the manufacture of hard and soft foams, adhesives, coatings, films and other products. Polyurethanes are usually synthesized by the reaction between isocyanates and polyols. However, concerns over declining oil resources, environmental pollution, and the price of oil-based materials have led to significant efforts to develop polyurethanes and polyols from biorenewable sources, especially in the adhesive and coating industries. In the present study, a wide ranges of vegetable oils used in the preparation of polyurethanes are reviewed and the chemical structures and synthesis methods of polyol, polyisocyanates and bio-based polyurethanes from vegetable oils are investigated. Then the properties of adhesives and coatings based on biomaterials are disscussed and compared with the properties of commercial adhesives. Studies show that the type of vegetable oil, NCO / OH ratio, flexibility and the presence of other additives are the most important parameters that affects the performance of polyurethane adhesives and coatings.

Color is an important key element in the architecture of Iranian mosques. Remarkable mosques of Shiraz which are belonging to the Qajarieh era have significant decorations such as tiling (Haft rang, mosaic and moqali),  inscription, carving, sash (colored glass), porcelain knots and Mogharnas. Nasir Al-Molk Mosque in Shiraz is known as the "jewel of Iranian mosques" due to its extensive decorations. The purpose of this study is to investigate the color palette in the architectural decorations of Nasir Al-Molk Mosque. The research method is descriptive-analytical and by investigating library resources and field research, information has been collected, studied, and explored. Findings of the current study show that the predominant color palette in buildings is warm shades, an issue that was not so common in religious architecture (mosques) before, and Nasir Al-Molk Mosque in Shiraz sought to deconstruct the color palette of religious buildings (mosques). This has led to an increase in the sensory and visual richness of the mosque's architecture. The study and investigation of color in the architecture of historic buildings can be a reference and answer to the visual and applied arts. 

Dyes have many uses due to their variety and complex structure.In recent years, wastewater from the production or consumption of dyes in various industries have increased and become a serious threat to the environment and human health.The effect of cold plasma as a new and advanced technology for the treatment of dye from wastewater is presented in this review paper. This method can be used for various applications such as treatment and pre-treatment of effluents, removal of pigments, and hazardous chemicals from effluents.In this wastewater treatment system, different cases such as characteristics of effluent, target materials, type of suitable plasma discharge, reactor type, toxicity experiments, biodegradability tests of plasma generated intermediates, environmental compatibility assessment of combined technologies, and economic estimation were considered. According to the studies, the results indicated the positive effects of cold plasma for decolorization of wastewater and also increased efficiency of modern wastewater treatment systems.  

Nanocelluloses, nanosized starches, and nanostructured chitins are the most abundant renewable biobased nanomaterials. These compounds were introduced as performance-enhancing agents for many future products due to their unique nanostructured properties. But, it was not yet determined how these specific properties influence biobased nanomaterial safety because they depend on many parameters. So far, few factors have been identified, such as their interactions with cells and organisms and exposure routes. Biobased nanomaterials are considered safe compounds due to their natural origin and environmental compatibility of their bulk forms. Published results on the safety of biobased nanomaterials show that they are generally not toxic to humans or the environment. However, they are not inert compounds and may also interact with the surrounding (for example, inflammatory effects in animal experiments. Among other factors, particle size and shape, aggregation characteristics, degree of branching, and specific surface properties, may affect the interactions of biological nanomaterials with cells and organisms. In addition, due to the significant variation in the properties of biobased nanomaterials, the toxicity test results obtained for the analyzed samples have been reported as valid. But this still requires more research and knowledge about the interactions of nanomaterials with living organisms. Therefore, the safety of biobased nanomaterials should be evaluated on a case-by-case basis, and the current guidelines and protocols for the use of nanomaterials need to be sufficiently developed. In addition, manufacturers of biobased nanomaterials should ensure the safety of their products during the whole life cycle of products, similar to products based on them. Nanoparticles are very reactive due to their small size and large surface area. This feature increases the risk of fire and explosion compared to larger particles. The most important methods for controlling exposure to nanoparticles are risk elimination, replacement of high-risk materials and processes with low-risk materials and processes, enclosure, engineering controls, management controls, and the use of personal protective equipment.

Conventional (active) and modern (passive) methods are available for ice removal from the surface. Passive approaches such as anti-ice coating do not require external energy. Anti ice coatings have diverse applications in disparate industries, including transportation, aviation industry, power transmission lines, and military applications. Due to the water repellency characteristics, anti-ice coatings reduce water accumulation on the surface. On the other hand, the elastic property of these coatings causes ice removal by weak mechanical forces, which leads to the emergence of easy defrost surfaces. In this paper, the prerequisites that are considered for acquiring anti-ice coatings are presented in the first place. Then active and passive methods are investigated, and the theory of each technique followed by an example for each is put forward.  Eventually, different evaluations which are available for anti-ice/ice phobic coatings are reviewed.