Nanocellulose: Preparation, Characterization and Applications

The growth of nanocellulose has attracted outstanding interest in the last few decades due to its unique and potentially useful features. Novel nanocelluloses improve the strongly expanding field of sustainable materials and nanocomposites.CNCs and CNFs are two kind of nanocelluloses (NCs), and they own various superior properties, such as large specific surface area, high tensile strength and stiffness, low density, and low thermal expansion coefficient.Their application includesnanocellulose in transdermal drug delivery, Hydrogels, Aerogel Systems, Nanocellulose in Tablet Formulations and Nanocellulose in Microparticulate Drug Delivery (1). Different methods of nanocellulose like pretreatment method, mechanical process and chemical hydrolysis used for the synthesis of nanocellulose. Characterization of cellulose includes scanning electron microscopy, x-ray diffraction (XRD) analysis of samples and thermogravimetric analysis.

Polymer Matrix Composite in High Voltage Applications: A Review

In recent years, natural fibers have become more widely used as reinforcement in polymer composites to generate low-cost products. Fibrous reinforcements in polymer matrices lead to good mechanical and electrical properties for composite materials. Depending on the grade and orientation, composites can be one-fifth the weight of steel while offering similar or better stiffness and strength. In addition, unlike steel or aluminum, composites do not rust or corrode. Composite materials reinforcing phase gives durability, strength, and stiffness. Composite materials have traditionally been employed as structural materials. Composite materials are increasingly being used in electrical applications such as bushings, circuit breakers, coupling capacitors, and so on, thanks to the growing growth of the electrical sector. The design parameters for structural and electrical composites differ dramatically due to the enormous differences in property requirements. Depending on the application, structural composites. Structural composites prioritize sufficient strength and modulus, while electrical composites prioritize superior dielectric constant, thermal conductivity and low thermal expansion, and shielding effectiveness. In the electrical industry, low density is desired because it allows for weight reduction. It is also desirable to have a high strength-weight ratio and dielectric properties. This paper provides a brief review of the properties of polymer composite materials and their application in the high voltage industry.

The use of Karelia’s finelyground mining waste and local clay for production of heatinsulating materials

The results of the study of fine-grained feldspathic and talcchlorite waste from Republic of Karelia’s mining companies as a new mineral product for heat-insulating materials and stationary heat accumulators (fireplaces and furnaces) are reported. The physico-mechanical and thermal-physical properties of the materials, based on finely ground waste and local clay, are appraised. The materials produced from pegmatite waste are highly strong, and can be used for lining furnaces and fireplaces. Heat-insulating materials based on talc-chlorite waste have low thermal expansion at 20‒900 °C, their thermal resistance increases 9 times (at 980 °C, water) and their mechanical strength is 2,6 times higher than that of samples containing talcum powder.

Using of the Tape Extensometer for Possibilities of Landslide Monitoring or another purposes

The main goal of this article is to analyze the possibility of using tape extensometry. It is one of the methods of evaluating the development of slope deformation. Tape extensometry is used to monitor the movement of the slope on the surface. Tape extensometry is used for fast and accurate measurement of relative distances between pairs of reference points on the surface of structures, including radial movements and convergence of tunnels, linings, shafts and caves. Then deformations of excavations in underground caves and displacements of retaining walls, bridge piers and arches. The digital tape extensometer is a portable device used to measure the displacement between pairs of eye bolts. The principle of measuring on a slope consists in directly measuring the distance between the stabilized measuring points. The measuring points are located in both stable and unstable parts. The measuring points are concreted into boreholes drilled to a non-freezing depth, which in the Czech Republic is about 0.8 m below the ground. The direction of movement can be determined by measuring the change in distance between several points located in the stable part and points in the unstable part. If we also measure in time intervals, we can also find out the approximate speed of movement. The tape extensometry method is performed using a tape extensometer. It is a specially adapted zone in which emphasis is placed on the material from which the meter is made, because it is important that the material has a low thermal expansion, for example nickel steel is suitable.

Rice-Husk-Ash-Based Geopolymer Coating: Fire-Retardant, Optimize Composition, Microstructural, Thermal and Element Characteristics Analysis

Geopolymer using aluminosilicate sources, such as fly ash, metakaolin and blast furnace slag, possessed excellent fire-retardant properties. However, research on the fire-retardant properties and thermal properties of geopolymer coating using rice husk ash (RHA) is rather limited. Additionally, the approach adopted in past studies on geopolymer coating was the less efficient one-factor-at-a-time (OFAT). A better approach is to employ statistical analysis and a regression coefficient model (mathematical model) in understanding the optimum value and significant effect of factors on fire-retardant and thermal properties of the geopolymer coating. This study aims to elucidate the significance of rice husk ash/activated alkaline solution (RHA/AA) ratio and NaOH concentration on the fire-retardant and thermal properties of RHA-based geopolymer coating, determine the optimum composition and examine the microstructure and element characteristics of the RHA-based geopolymer coating. The factors chosen for this study were the RHA/AA ratio and the NaOH concentration. Rice husk was burnt at a temperature of approximately 600 °C for 24 h to produce RHA. The response surface methodology (RSM) was used to design the experiments and conduct the analyses. Fire-retardant tests and thermal and element characteristics analysis (TGA, XRD, DSC and CTE) were conducted. The microstructure of the geopolymer samples was investigated by using a scanning electron microscope (SEM). The results showed that the RHA/AA ratio had the strongest effect on the temperature at equilibrium (TAE) and time taken to reach 300 °C (TT300). For the optimization process using RSM, the optimum value for TAE and TT300 could be attained when the RHA/AA ratio and NaOH concentration were 0.30 and 6 M, respectively. SEM micrographs of good fire-resistance properties showed a glassy appearance, and the surface coating changed into a dense geopolymer gel covered with thin needles when fired. It showed high insulating capacity and low thermal expansion; it had minimal mismatch with the substrate, and the coating had no evidence of crack formation and had a low dehydration rate. Using RHA as an aluminosilicate source has proven to be a promising alternative. Using it as coating materials can potentially improve fire safety in the construction of residential and commercial buildings.