Background: a humidity sensor is used to sense and measure the relative humidity of air. A new composite system has been fabricated using environmental pollutants such as carbon black and low-cost zinc oxide, and it acts as a humidity sensor. Residual life of the sensor is calculated and an expert system is modelled. For properties and nature confirmation, characterization is performed, and a sensing material is fabricated. Methodology: characterization is performed on the fabricated material. Complex impedance spectroscopy (CIS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) are all used to confirm the surface roughness, its composite nature as well as the morphology of the composite. The residual lifetime of the fabricated humidity sensor is calculated by means of accelerated life testing. An intelligent model is designed using artificial intelligence techniques, including the artificial neural network (ANN), fuzzy inference system (FIS) and adaptive neuro-fuzzy inference system (ANFIS). Results: maximum conductivity obtained is 6.4×10⁻³ S/cm when zinc oxide is doped with 80% of carbon black. Conclusion: the solid composite obtained possesses good humidity-sensing capability in the range of 30–95%. ANFIS exhibits the maximum prediction accuracy, with an error rate of just 1.1%.
In this study, we investigated the bonding mechanism of surface-treated steel with an Al-Si alloy in order to produce steel-aluminum (STL-Al) hybrid composite materials by cast-bonding. The results showed that there are differences in the phase and properties of the hybrid composite materials bonded specimens depending on the surface treatment of the steel sheet used, and that the bonding conditions can be controlled further by detailed conditions of the surface treatment. Based on the interfacial bonding strengths measured here, the galvanized surface treatment induced metallurgical bonding to form a reaction layer on the bonding surface and was determined to be the most effective surface treatment.
A high performance and light-weight wound composite material wheel has been developed and is intended to be used for many purposes. One of these applications is marine current turbine (MCT). Traditionally, major problems influencing the design and operation of MCTs are fatigue, cavitation and corrosion due to the sea water. Considering these factors, implementation of composite materials, especially Kevlar fiber/epoxy matrix, in MCTs is explained in this paper. This novel design pattern of composite material marine current turbine (CMMCT) shows many advantages compared to conventional turbines. This paper investigated several factors which should be considered during this novel turbine design process such as the composite material selection, filament winding of composite wheel and turbine's structural and cavitation analysis. The power coefficient of CMMCT by using CFD is also obtained and the experimental facilities for testing CMMCT in a water towing tank are briefly described.
The aim of this paper is analysis of the possibility of determining the internal structure of the fibrous composite material by estimating its thermal diffusivity. A thermal diffusivity of the composite material was determined by applying inverse heat conduction method and measurement data. The idea of the proposed method depends on measuring the timedependent temperature distribution at selected points of the sample and identification of the thermal diffusivity by solving a transient inverse heat conduction problem. The investigated system which was used for the identification of thermal parameters consists of two cylindrical samples, in which transient temperature field is forced by the electric heater located between them. The temperature response of the system is measured in the chosen point of sample. One dimensional discrete mathematical model of the transient heat conduction within the investigated sample has been formulated based on the control volume method. The optimal dynamic filtration method as solution of the inverse problem has been applied to identify unknown diffusivity of multi-layered fibrous composite material. Next using this thermal diffusivity of the composite material its internal structure was determined. The chosen results have been presented in the paper.