Science and Technology - Recent Updates and Future Prospects Vol. 8

Laminated composites are integral to numerous engineering industries, including aerospace, marine, automotive, and storage solutions. This chapter focuses on the three-dimensional deformations of a multilayered, linear elastic, anisotropic rectangular plate, which is subjected to arbitrary boundary conditions on one edge and simply supported on the opposite edge. The laminate comprises anisotropic and homogeneous layers of varying thicknesses.

We present an elastic analysis of these laminated composite plates under sinusoidal mechanical loading and diverse boundary conditions. Utilizing a state-space model, we employ the least-squares finite element method (LSFEM) to obtain solutions for displacements and stresses. This method ensures the continuity of field variables across the composite structure's domain and at the layer interfaces, thereby addressing common issues such as shear locking and improving the accuracy of the simulation.

The governing equations are formulated using LSFEM, which minimizes the residuals of the governing equations and side conditions across the computational domain. Our model incorporates layerwise variables, including displacements, out-of-plane stresses, and in-plane strains, treating them as independent variables. This approach allows for a more detailed and precise analysis of the composite's behavior under various loading conditions.

Numerical results illustrate the behavior of the laminated composite plates under various boundary conditions, demonstrating the effectiveness of the LSFEM approach. These results are compared with existing three-dimensional elasticity solutions in the literature, validating the accuracy of our method. The chapter also discusses the implications of different boundary conditions on the mechanical response of laminated composites, providing insights into optimal design strategies for engineering applications.

Bowtie antennas give multifunction capability in modern wireless communication systems. The bow-tie antennas in this research work are used to design multiband antennas using different substrates. Bow tie designs are suitable for diverse multiband applications. We discuss design using dielectric substrates FR4, Arlon 217, Rogers and RT Duroid 6002.The  antenna is designed at an operating frequency of 10GHz.With Arlon Cuclad 217 substrate multiband frequencies are 3.5GHz,7.0GHz,10.5 GHz, with FR4 substrate 11.2 GHz and with RTDuroid 6002 multibands are obtained at 1.8GHz,4.0GHz,6.0GHz 7.75GHz ,9.5GHz and 11.5 GHz and 13.5 GHz. Specific objectives of this research is comparative analysis of Bowtie Antenna by using various substrates and by changing operating frequency. The basic bowtie antenna is modified using a coplanar waveguide feed (CPW). The antenna behaviour is also studied as cognitive antenna by inserting an inductors of two different shapes zigzag and rectangular shapes between the bows of the antenna. With both the inductors inserted between the bow antenna all parameters obtained are same but radiation pattern and polar plots are different. The antenna operating frequency also switched from 10 GHz to 25GHz  with the rectangular shape inductor. Thus, using a simple inductor gives frequency switching from 10 GHz to 25 GHz and with a switch in gain. Moreover, the inductor shape makes frequency switch of multibands 9.3 - 10.30 GHz to 11.35 GHz with also a gain switch from 4.99 to 6.9 GHz. Thus, these antennas makes them suitable to increase network links. 

Due to the occurred increasing in information sharing, internet popularization, E-commerce transactions, and data transferring, security and authenticity become an important and necessary subject. During recent years and yet now the terms of security, data integrity, authenticity are very concern, whereas in order to authenticate users of any service that is worked online, the authentication of password is used. In this paper an automated schema was proposed to generate a strong and complex password which is based on entering initial data such as text (meaningful and simple information or not), with the concept of encoding it, then employing the Genetic Algorithm by using its operations crossover and mutation to generated different data from the entered one. The generated password is non-guessable and can be used in many and different applications and internet services like social networks, secured system, distributed systems, and online services. The proposed password generator achieved diffusion, randomness, and confusions, which are very necessary, required and targeted in the resulted password, in addition to the notice that the length of the generated password differs from the length of initial data, and any simple changing and modification in the initial data produces more and clear modification in the generated password. The generated password cannot be remembered, so that the application of such password is as a master password, which is saved in a file after it was generated and it is used in user specific configuration data for access the server, also it can be distributed among the users who share information and data, it can also be used for barcode generation for commercial field. The proposed work was done using visual basic programing language.

The wildfire is the most alarming threat to ecosystems, whether human-made or natural. Unfortunately, fires destroy many hectares of forest area each year due to late and ineffective fire detection. It is crucial to detect forest fires early to prevent them from spreading widely and harming the environment. Many research has been conducted in this field, but effective fire detection and reduction remain a challenge. The proposed system aims to address this challenge by developing a firefighting machine using advanced Artificial Intelligence (AI) and Internet of Things (IoT) technology. Currently, it is undergoing field trials. The primary objective of this machine is to generate artificial rain through drones equipped with sodium bicarbonate. This process aims to seed clouds and produce rain droplets to mitigate fire outbreaks. Data collection is automated, with information being captured and stored in a cloud-based system via the IoT. Images of both fire and normal conditions are collected and used to train AI models for wildfire detection. TensorFlow is utilized to support drone operations in this process. The IoT cloud platform, Thing Speak, is chosen for its efficiency and reliability in managing data modules. The stored data in the cloud is crucial for training AI models effectively, enabling accurate wildfire detection and timely response. The designed AI and IoT-enabled drones can accurately detect fires and deploy artificial rain to suppress them immediately.

Time series prediction is a critical area of research with applications in various domains such as finance, weather forecasting, and stock market analysis. In this paper, we present a comparative analysis of two popular methods for time series prediction [1]: Fourier Transformation and the Autoregressive Integrated Moving Average (ARIMA) model. We took a dataset representing climate data for the state of Madhya Pradesh for a period of 2000 days. We took three analytical metrics: pressure, humidity and temperature to evaluate the performance of each method. We independently processed each metric and plotted the graph for predicted data to do the analysis. Subsequently, we implement the ARIMA model on the same dataset. We used Root Mean Squared Error test to find the accuracy for both Fourier and ARIMA model and compared the performance of the two methods based on the results of RMSE test. Our results indicate that temperature and humidity is predicted better with ARIMA model while pressure is better predicted by Fourier transformation. This study contributes to the existing body of knowledge by providing insights into the effectiveness of these methods for time series prediction, and can assist researchers and practitioners in selecting the appropriate approach for their specific needs.

In this study (Part III), effects of the mechanical and thermal forcing on the 2007-08 Madden-Julian Oscillation (MJO07-08) system during the splitting stage over the New Guinea Highlands (NGH) are investigated. During the splitting stage of MJO07-08 convective system following the blocking stage highlights the relatively stronger role played by thermal forcing associated with the NGH, owing to the interaction between land/sea breeze and the basic flow. Moreover, the mechanical forcing influences the amount of rainfall along NGH as the weakened mesoscale convective system (MCS) and incoming flow associated with MJO07-08 interact with the complex terrain of NGH. This study also explores how the common ingredients and major mechanisms for heavy rainfall, as identified in the previous studies, are affected during the splitting of the MCS around NGH. In short, this research provides in-depth insights into the roles of mechanical and thermal forcing on the rainfall modification and propagation of MJO07-08 over the NGH. By employing the Weather and Research Forecasting (WRF) model, the research uncovers the significance of these factors influencing orographic blocking, flow regimes, and the NGH modification of the MJO07-08 rainfall.

This work reports the results of experimental investigations carried out on a submerged synthetic jet obtained through the use of a headset speaker piloted with an appropriate sinusoidal signal at a frequency of 380 Hz. The purpose of making such a device is to obtain a manufacture that can improve human comfort, in cases where there is prolonged contact of parts of the human body with fabric and/or padding such as, for example, in the case of professional drivers or in the case of patients immobilized in bed for long periods and who may develop sores from decubitus. The study begins with the construction of a device that, exploiting the well-known transport properties of impacting jets, was able to improve local ventilation and the removal of excess moisture, due to the natural transpiration of human skin in people forced to assume the same position for prolonged periods such as professional drivers; bedridden patients; etc. It is essentially imposed upon subjects to have portions of their own bodies in contact with materials and coverings that obstruct typical skin transpiration conditions. The structure of the synthetic jets was studied in advance of the experimental activity, which subsequently involved building a sponge mat with 80 separate jets. Semi-empirical tests were conducted on this sponge mat to see how well distilled water could remove moisture from a cloth.

The experimental investigations were first carried out using the PIV technique, and, subsequently, the synthetic jet was visualized using the Background-Oriented Schlieren (BOS) technique which allowed to test the presence of the jets, installed directly on the mattress, in a relatively simple and fast way, requiring a very simplified set-up. The first series of empirical tests were carried out to verify the ability to remove moisture from a fabric, previously soaked in distilled water, exposed to the action of the synthetic jets made. The results of these latest tests, although encouraging, require further analyzes to be carried out quantitative information, like the moisture evaporation rate, under controlled environmental humidity and temperature.

For the calculation of a rotating disc, having a uniform thickness, made of functionally graded materials, the finite element method is used based on the concepts of multilayer disc and equivalent material. These concepts are available for analytical calculus as well. The multi-layered disc concept considers the disc made of several layers, and the equivalent material concept considers the disc material made of homogeneous and isotropic material. This material has fictitious properties that ensure the same behavior as that of the functionally graded material. The influence of Poisson's ratio can be determined and it is illustrated by some comparative results. The development of the calculus, the validation of the models and the analysis of the results are based on the numerical calculus using the finite element method. The models used, are based on the existence of the axial-symmetric plane. So, we can use 2D or 3D simplified models, with several variants regarding the fineness of the mesh. The results of the study, the models and concepts used are useful to specialists and designers of structures of this type, they have a high degree of generality and present openings for the use of other calculation methods.