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In this study, the influence of phase change materials (PCM) on the thermal behaviour of concrete sandwich panels was investigated. Sandwich panels are known for their high thermal efficiency however, this research proposed the integration of a PCM concrete layer to maximize the ability of PCM to store heat and slow down the rate of heat transfer. The thermal behaviour was tested by supplying heat energy to specimens until the core temperature reached 60°C. Specimens were allowed to cool until the core temperature returned to 40°C. The thermal behaviour was recorded and analysed. Three specimen types were tested: solid panels (SL), sandwich panels (SW) with and without a PCM concrete layer. For all SW panels, a 10-mm air gap was introduced between two layers at three different locations. Results showed that the air gap behaviour was modified with the heat transfer process by creating temperature lagging, thus resulting in a slower rate of heat transfer across the specimens. The temperature lagging was observed in SW panels and varied depending on the location of the air gap. The application of PCM in SW panels further reduced the rate of heat transfer and decreased the fluctuation of temperature lagging magnitude. [ABSTRACT FROM AUTHOR]

As environmental pollution and safety of human and creatures have been an issue of concern, pest management based on nonchemical use is preferable. Biological pest control can satisfy the regulation of pest population without causing environmental problems. Moreover, representation of dynamical systems in the form of fractional‐order dynamic models can explain several phenomena better than the integer‐order dynamic models can. The aim of this study is to determine the biological pest control policy for the fractional‐order pest control systems, which is a complex nonlinear multiple input and multiple output control problem. Here, the system is represented in the form of a fractional‐order Lotka–Volterra model. In order to avoid complexity in the nonlinear feedback controller design process, the tensor product (TP) model transformation was applied to automatically transform the biological pest control system to the TP polytopic model which allows the designer to synthesize the controller under linear framework. Moreover, the design process can be easily carried out by solving an linear matrix inequality (LMI) problem, which is very well applicable to high‐dimensional multiple input and multiple output control problems. Simulation studies were conducted to demonstrate the ease of the TP‐based design process. The simulation results showed that the designed control policy effectively manipulates the pest populations of the fractional‐order Lotka–Volterra model to the desired level which is economically viable. [ABSTRACT FROM AUTHOR]

Flexible structures have been increasingly utilized in many applications because of their light-weight and low production cost. However, being flexible leads to vibration problems. Vibration suppression of flexible structures is a challenging control problem because the structures are actually infinite-dimensional systems. In this paper, an adaptive control scheme is proposed for the vibration suppression of a piezo-actuated flexible beam. The controller makes use of the configuration of the prominent proportional-integral-derivative controller and is derived using an infinite-dimensional Lyapunov method. In contrast to existing schemes, the present scheme does not require any approximated finite-dimensional model of the beam. Thus, the stability of the closed loop system is guaranteed for all vibration modes. Experimental results have illustrated the feasibility of the proposed control scheme. [ABSTRACT FROM AUTHOR]

This paper presents an application of fractional-order control to industrial electrohydraulics. An optimization based frequency domain approach is used to obtain a fractional-order proportional-integral controller for force control of an electrohydraulic actuator. The controller is designed to have a feature of robustness to gain variations with the step responses exhibiting an iso-damping property. In practice, the gain variations are due to the changes in the environment or the load's force interacting with the actuator. Results of real life experiments demonstrate the effectiveness of the controller. [ABSTRACT FROM AUTHOR]