نشریه مطالعات در دنیای رنگ
سال هفتم شماره 4 (پیاپی 27، زمستان 1396)

Typically, equipments and devices that are subject to vibration or continuous movement such as cars usually are faced to loose or unplugged metallic joints, which causes metal joints not to function properly and further intensive damages can be occurred. One of the methods to enhance metallic joints is the use of thread locking adhesives. thread locking adhesives not only prevents the metal fittings from loosening, but also by filling the gap between metal fittings, prevents the penetration of oxygen and moisture into them and delaying the occurrence of corrosion. These adhesives contain microcapsules filled with active thermoset monomers, which are well-dispersed in a thermoplastic media. At the time of fixing the connection, and due to the applied mechanical force from the closure of the nut on the adhesive-coated screw, the microcapsule shells rupture and the reactive monomers release and flow into the gaps between the screw and the nut, and finally by chemical reactions, the connection between the screw and the nut is tightened. Therefore, this type of adhesive reveals appropriate storage time, with proper bonding strength between the joints, at the service life. In this article, we introduce and investigate the thread lockers adhesives containing microcapsules filled with reactive monomers.

Due to the importance of fire resistant subject in the safety of buildings, the present article reviews on the various types of fire retardant coatings. These coatings are usually applied on architectural wall and metal structure for resisting against fire propagation. Fire retardant coatings are classified into two groups: fire retardant paints and mineral coatings. Fire retardant paints are divided to intumescent and non- intumescent paints. The resistance of fire retardant coatings is varied from 30 min to 4 h, depending on dried film thickness. This article studies on the different types of fire retardant coatings and their ingredients.

Azo dyes for coloring food products are added to food to not only look beautiful, but the original appearance of its effects remain constant during the manufacturing process. However, many countries around the world have banned the majority of azo dyes in food and the use of these colors heavily through the food supply domestic and export reviewed and controlled. Accurate and sensitive analytical methods for food control experts to monitor and ensure the quality and safety of food products adopt. This article is a comprehensive review of various analytical techniques used in the study azo dyes used in the food industry around the world offers

One of the ways to optimize energy consumption and reduce pollutants in the environment is to reduce energy consumption for brightness. In this field LED bulbs have attracted a great attention due to many advantages they have over other types of lamps, in addition to high efficiency. The construct of these types of lamps, consists of a blue color diode and a phosphor that is applied to it. Phosphor must be in yellow spectra or a combination of red and green in order to obtain a white color. Since being the light produced close to sunlight is important, several parameters are considered in the selection of materials. In phosphor synthesis for white LED, the purpose of doping is increasing Color Rendering Index. The purpose of this paper is to study a variety of materials that can be applied as phosphorus on a diode to create white light.

Since a long time, energy has been one of the important problems of humanity. There are various sources to generate energy which fossil fuels are more common, but they are polluting the environment. Today clean and non-polluting energy production has become the most important priority of researchers around the world. There are different methods for producing clean energy, which solar energy has a special site due to the lack of pollutants. The main problem with solar cells is the low efficiency and high cost. The common solar cells have a maximum yield of 20% but there are another category of solar cells that are known as concentrated photovoltaic has a yield of 40% or more. This paper decided to introduce and discuss about the structure, advantages and disadvantages of this group of solar cells.

Today, scientists pay much attention to application of renewable energy resources, especially solar energy, due to its high capacity, availability and low cost. Thus, understanding and realizing the methods to covert solar energy to electricity is a key to improvement of this technology. Solar cells are devices that convert directly solar energy to electricity based on photovoltaic effect. Two main categories of solar cells including dye sensitized solar cells DSSCs and polymer solar cells PSCs have been considered in the present review paper. Photon absorber materials or electron-hole generators are one of the main components in the structure of solar cells. In DSSC, dye absorbs light and transfer electron to semiconductor material. Therefore it’s an important parameter to recognition the dye structure and performance. So, different dyes introduction, performance mechanism and their improvement for application in DSSCs is considered in this paper. Also in recent years, application of dyes in PSCs has been reported; therefore some of these applications have been investigated. Finally, the performance mechanism of dye in the presence of polymer Forster Mechanism in PSCs is presented.