Modelling of Lamb Waves Propagation in Orthotropic Plate

In this chapter, we model by Finite Element Method (FEM) the Lamb waves' propagation and their interactions with symmetric and asymmetric delamination in sandwich skin. Firstly, a theoretical model is established to obtain the equation of lamb modes propagation. Secondly, dispersion curves are plotted using Matlab program for the laminate [0]4. The simulations were then carried out using ABAQUS CAE by exciting the fundamental A0 Lamb mode in the frequency 300 kHz. The delamination was then estimated by analyzing the signal picked up at two sensors using two techniques: Two Dimensional Fast Fourier Transform (2D-FFT) to identify the propagating and converted modes, and Wavelet Transform (WT) to measure the arrival times. The results showed that the mode A0 is sensible to symmetric and asymmetric delamination. Besides, based on signal changes with the delamination edges, a localization method is proposed to estimate the position and the length of the delamination. In the last section, an experimental FEM verification is provided to validate the proposed method.

Solar Micro-Inverter

A solar micro inverter is a small-size inverter designed for single solar PV module instead of group of solar PV modules. Each module is equipped with a micro inverter to convert the DC electricity into AC electricity and the micro inverter is placed/installed below the module. The advantages of micro inverters are: reduced effect of shading losses, module degradation and soiling losses, enabled module independence, different rating of micro inverter can be connected in parallel to achieve the desired capacity, additional modules can be included at time which allows the good scalability, string design and sizing are avoided, failure of any micro inverter does not affect the overall power generation, individual MPPT controller for each module increases the power generation, any orientation and tilt angle allows higher design flexibility, lower DC voltage increasing the safety, easy to design, handle and install, requires less maintenance, draws attention of design engineers, contractors, etc.

Antilock Braking System Formal Modeling

Antilock Braking System (ABS) is one of the most critical systems in the context of vehicles' mechatronics. The main purpose of the ABS system is allowing the wheels to stop while preventing sliding. It is responsible for ensuring a secure stopping of the vehicle, a very critical factor in trip safety. Therefore, the process of its construction should be performed with high care, and this is why theoretical modeling is highly needed. In order to help engineers to develop and study such a critical system, we propose a standard model that includes the essence of Antilock Braking System using a formal method called Event-B. This model may be used to reveal some bugs during proving that may go otherwise undetected. At the same time, the model can be animated to observe the system behavior.

Study and Design of New Rectenna Structures for Wireless Power Transmission Applications

This chapter presents many research works that have been carried out to deal with the problem of power supply to remote sensors. A 2.45 GHz voltage multiplier rectifier was validated to deliver 18V of output voltage with a conversion efficiency of 69%. Another rectenna was fabricated at 5.8 GHz of the Industrial Scientific Medical band and reach a measured voltage of 7.4V at 18 dBm. The third structure is about a series rectifier working at 2.45 GHz associated with a microstrip low pass filter which produces a supplying voltage of 11.23V. Added to the aforementioned results, the objective in this work is to design, optimize and realize two structures: A dual band patch antenna working at 2.45 GHz and 5.8 GHz, and a compact rectifier circuit at 2.45 GHz for the power supply of low-consumption devices. This rectifier has been designed using Advanced Design System. The bridge topology was employed on an FR4 substrate. A good matching input impedance was observed and high conversion efficiency was obtained. Simulation results have been validated through realization and measurements.

Property Enhancement of Carbon Fiber-Reinforced Polylactic Acid Composites Prepared by Fused-Deposition Modeling

Additive Manufacturing or three-dimensional printing refers to a process of building lighter, stronger three-dimensional parts, manufactured layer by layer. Additive manufacturing uses a computer and CAD software which passes the program to the printer to build the desired shape. Metals, thermoplastic polymers, and ceramics are the preferred materials used for additive manufacturing. Fused deposition modeling is one additive manufacturing technique involving the use of thermoplastic polymer for creating desired shape. Carbon fibers can be added into polymer to strengthen the composite without adding additional weight. Present work deals with the manufacturing of Carbon fiber-reinforced Polylactic Acid composites prepared using fused deposition modeling. Mechanical and thermo-mechanical properties of composites are studied as per ASTM standards and using sophisticated instruments. It is observed that there is enhancement in thermo-mechanical properties of composites due to addition reinforcement which is discussed in detail.

LEDs for Solid-State Lighting

Solid-state lighting technology is rapidly gaining acceptance in lighting industry street lighting, traffic lighting, decorative lighting, projection displays, display backlighting, automotive lighting, and so on. Differing from conventional light sources that use tungsten filament, plasma, or gases to generate light, solid-state lighting is based on organic or inorganic light emitting diodes (LEDs), and has the potential to generate light with almost 100 % efficiency. LED luminaires have a long lifetime and are environmentally friendly with no toxic mercury contained. However, the success of these luminaires depends on system design, which comprises an understanding of several factors such as performance and control. In this chapter, we shall touch upon some technological advancements in the field of solid-state lighting technologies and challenges that limit their market penetration for consumer lighting.

Microwave Complex-Ratio-Measuring Circuits

This chapter reviews the microwave complex ratio measuring (MCRM) circuits which are used for complex reflection coefficient measurement. This MCRM circuit is relatively simple and cost-effective. There are various structures for the MCRM circuit, such as multi-probe transmission line circuits, five-port ring circuits, six-port hybrid coupler-based circuits, switched-reflector circuits, dual-generator circuits, and Wheatstone bridge-based circuits. Each structure of the circuits has its own advantages and disadvantages. In this chapter, the MCRM circuit calibration process has been described in detail.

Computer-Aided Design and Applications of Planar Branch-Line Coupler Circuits

This book chapter mainly focuses on analytical analysis for the branch-line coupler in which this method provides an explicit solution in the coupler design. Generally, the directional coupler is one of the fundamental components for Microwave Integrated Circuit (MIC), especially the equal power-split coupler that is used for signal monitoring, power measurement, power division, and balanced-type components such as balanced mixers. In this chapter, several applications of the branch-line coupler are also described. The analytical and design formulations of the coupler are derived based on ABCD matrix, transmission line principle, and even-odd mode decomposition. Although the simple analytical analysis is not sufficiently implemented in complex coupler structure, it is capable of providing an initial design guideline for the coupler dimensions. The initial design of the coupler dimensions based on analytical analysis can be gradually modified and optimized to achieve the desired size or performance of the coupler using advanced numerical simulation.

Performance Analysis of Hierarchical Routing Protocols in Heterogenous WSNs

Since the appearance of WSN, the energy efficiency has been widely considered as a critical issue due to the limited battery-powered nodes. In this regard, communication process is the most energy demanding in sensor nodes. Subsequently, using energy-aware routing protocols in order to decrease the communications costs as much as possible and increase the network lifetime is of paramount importance. In this chapter, we have mainly focused on the most recent-based clustered routing algorithms for heterogeneous WSNs, namely Selected Election Protocol (SEP), and Distributed Energy Efficient Clustering Protocol (DEEC). In addition, we have proposed an efficient clustered routing protocol based on Zonal SEP algorithm. Indeed, we have evaluated the performance of the proposed protocol according to different scenarios in order to guarantee the best distribution of heterogeneous nodes in the network. The results have shown that the proposed clustered routing approach outperforms the existed Z-SEP protocol in terms of energy efficiency and stability.

Autoencoders in Deep Neural Network Architecture for Real Work Applications

The most heard sound exists as a mixture of several audio sources. All human beings have the ability to concentrate on a single source of their interest and ignore the other sources as disturbing background noise. To apply this powerful gift to a machine, it must obligatory pass through the source separation process. If there is not enough information about the process of mixture of those sources and their nature as well, the problem is known by Blind Source Separation BSS. This thesis is dedicated to study the BSS as a solution for human machine interaction. The objective consists in recovering one or several source signals from a given mixture signal. Recently, the science research is towards artificial intelligence and machine learning applications. The proposed approach for the separation will be to apply a Deep Neural Network method based on Keras. Extracting features from the audio with signal processing techniques and machine learning to learn a representation from the audio for the compression tasks and the suppression of the noise will improve the state-of-the-art.