Reducing the Fire Hazard of Wooden Structures

Increasing the fire resistance of wooden structures is relevant because of their increased flammability. The article describes an experimental study using NEOMID flame retardant paint and silica powder as a flame retardant for wooden structures. According to the results of the experiment, a group of fire-retardant effectiveness of the tested fire-retardant composition was established with different methods of its use.

Analysis of Carotenoid Pigment Types in the Carapace of the Male Crab Grapsus albolinetaus Latreille in Milbert 1812

Carotenoid pigments have various colors such as yellow, orange, or red-orange. One of the carotenoid pigment sources is Crab G. albolineatus Latreille in Milbert 1812. Column chromatography separation technique was used to determine the metabolism of carotenoid pigments in the crab G. albolineatus latreille in Milbert 1812. This CC separation used hexane and acetone as the developer solution (70:30). The developer solution as known as the mobile phase is semipolar, while the stationary phase is silica powder G60. Therefore, it formed two metabolic pathways. The male G. albolineatus crab used in this study was on the D3 molting stage which had a concentration of 36.37 g/g dry residue and 4.72 g content. The types of pigments identified are: β – karoten, Zeaxanthin, lutein, β – kriptoxanthin dan Astaxanthin.Keywords: Carotenoid Pigments; G. albolineatus; Column Chromatography; MoltingAbstrakPigmen karotenoid memiliki berbagai warna seperti kuning, oranye, atau merah oranye. Salah satu sumber pigmen karotenoid adalah pada karapas kepiting G. albolineatus Latreille in Milbert 1812. Untuk mengetahui metabolisme jenis pigmen karotenoid pada kepiting Grapsus albolineatus latreille in Milbert 1812 yaitu menggunakan pemisahan kromatografi Kolom. Pemisahan KK ini menggunakan larutan pengembang heksan dan aseton (70:30). Larutan pengembang merupakan fase gerak yang bersifat semipolar dan fase diamnya menggunakan bubuk silika G60. Terbentuk dua jalur metabolisme. Kepiting G. albolineatus jantan yang digunakan pada penelitian berada di stadium molting D3 dengan konsentrasi sebesar 36,37 µg/g berat residu kering dan kandungan 4,72 µg. Jenis pigmen yang teridentifikasi yaitu : β – karoten, Zeaxanthin, lutein, β – kriptoxanthin dan Astaxanthin.Kata kunci: Pigmen; Karotenoid; G. albolineatus; Kromatofrafi Kolom; Molting

MECHANOCHEMICAL AND ULTRASONIC TREATMENT – A CONTROLLED METHOD FOR FORMING THE STRUCTURE AND PROPERTIES OF NANOCOMPOSITE GEL SYSTEMS

In this work, the preparation of colloidal systems with microcrystalline cellulose as a gelling agent and silica powder as a filler was considered. By mechanochemical and ultrasonic treatment of a filler made of silicon dioxide and a colloidal base, varying the constituent ingredients, one can purposefully influence the structure of the system and regulate the properties of the resulting compositions. It is shown that the introduction of a filler made of highly dispersed silicon dioxide into a gel system based on cellulose, modified by ultrasonic treatment (UST) with acid additives, provides both acceleration of the gelation process and stabilization of the state of the obtained colloidal composition. As a result of UST, a nanostructured colloidal homogeneous system is formed.

The Effect of Variation Concentration Cristobalite Silica from Natural Silica Sand to Hydrophobicity on Steel Plate Surface

In this research, pure silica powder has been synthesized from the sand of the Bangka-Belitung Islands. Natural sand is extracted with permanent magnets and immersed with HCl to obtain pure silica, followed by coprecipitation and calcination processes at a temperature of 900 °C for 10 hours. The final result of the synthesis process is pure silica powder in the cristobalite phase (83.03% wt) and the tridymite phase (16.97% wt). The synthesized silica powder is used as a modification on topcoat of steel to increase the hydrophobicity of steel plate surface so that it can reduce the rate of corrosion. Steel plate has been painted by using the brush painting method and consists of three layers, namely the primary layer, midcoat and topcoat. The variation in this research is the concentration of silica powder on the topcoat of steel such as 0% wt (sample 1), 3% wt (sample 2), 6% wt (sample 3), 9% wt (sample 4), and 12% wt. (sample 5). These variations have an effect on the surface geometry of the steel plate, namely the surface gets rougher as the concentration of silica powder is mixed. The hydrophobicity of the steel plate can be seen from the measurement Water Contact Angle (WCA). The WCA using fresh water in sample first until five’th are 75,828 ̊, 90 ̊, 91,397 ̊ 96,520 ̊, and 104 ̊, respectively. While the WCA using seawater in sample first, second and fourth are 80.618 ̊, 102 ̊, and 104.56 ̊, respectively.