Fundamental Research and Application of Physical Science Vol. 5

Shielding electronic circuits from electromagnetic interference (EMI) is crucial in the aerospace industry, particularly for space vehicles, as EMI can have significant impacts on the functioning of various devices. Shielding effectiveness (SE) is the industry-standard measure of EMI shielding. This study aims to evaluate the SE of three types of infinite sheet metals against magnetic, electric fields, and plane waves generated by the electromagnetic pulse from a system. Maxwell's equations were used to calculate the SE to determine whether the selected tapes conform to the 40 dB SE requirement specified in electromagnetic compatibility (EMC) specifications. Using MATLAB, absorption loss, reflection loss, re-reflection correction factor, and SE were computed. The findings highlight the importance of proper EMI shielding in aerospace design and demonstrate how different sheet metals can provide varying levels of protection against EMI.

The objective of this study is to provide useful information for the fabrication of large plastic scintillators that can be utilized in radiation portal monitors (RPMs). A plastic scintillator was fabricated using the injection method, with polystyrene (PS) as the matrix, and para-terphenyl (PTP) and 1,4-bis [2- (phenyloxazolyl)] - benzene (POPOP) as primary and secondary dopants, respectively. The scintillator was characterized based on its absorption spectrum, emission spectrum, and gamma radiation spectrum. The absorption spectrum evaluation using a spectrophotometer UV-Vis revealed that PS absorbs photons at a wavelength of 310 – 340 nm. The emission spectrum evaluation showed that PS containing POPOP exhibited a maximum emission at a wavelength of 421 nm. The evaluation of cesium 137 (¹³⁷Cs) and cobalt 60 (⁶⁰Co) gamma spectrum using the photomultiplier tube (PMT) Hamamatsu R878 showed that the scintillator exhibited Compton spectrum characteristics, with a gross counting maximum of 0.78 and 0.89, respectively, compared to a commercial plastic scintillator.

The modern automatic control systems are the systems with pulse semiconductor converters power, digital sensors of mechanical variables – torque and movement speed, and digital control devices – regulators. All these devices “break” the signals in time, that is, they make them discrete. Time discretization significantly affects the stability of processes in ACS. Theoretical analysis of ACS even with one discrete element demands a transfer from continuous frequency characteristics and transfer functions of all links of the ACS structure to the discrete characteristics. That significantly demands the change of engineering approaches to the ACS analysis. In recent years, due to a significant reduction in the sampling time in digital sensors and controllers, the influence of discreteness on the ACS stability has weakened, and little attention has been paid to it in research. However, the mathematical “content” of the problem has not changed since the 80s of the 20th century.Moreover, this problem is very relevant in high-precision high-speed automatic control systems, especially in those using sliding processes.In this paper a new approach is proposed, which consists in interpreting the discretization operation by a link that suppresses input signals with a high variation frequency. This link greatly simplifies the engineering calculations of ACS with discretization and shows new possibilities for the synthesis of such systems. Such possibilities include the efficient distribution of sampling intervals between the channels of widely used PID controllers and the channels of amplification and formation of slip trajectories in systems with a variable structure with sliding processes (SVS with SP) that have been rapidly developing in recent years. It is specifically important that the proposed estimation technique remains effective when the discretization intervals are comparable with the times of transient processes in the ACS under consideration. Theoretical provisions have been verified and confirmed by modeling, the results of which are given in this chapter.

In order to maximize maximise the temperature of the ground heat exchanger (GHE), this chapter presents a mathematical model of the behavior of heat transfer between the liquid inside vertical underground geothermal pipes and the surrounding ground.  The GHE is a crucial component of the GHPS and plays a key role in utilizing the earth’s heat energy by exchanging heat with the ground due to its actual contact. Most benefits from the earth’s thermal energy can be attained when the GHE is well-designed, including in terms of configuration, installation location, borehole heat exchanger capacity, and performance factors, which ensure that the GHE’s output temperature reaches the ground temperature.

The heat transfer mechanism between the circulating water inside the vertical U-tube pipe and the surrounding grounds is as follows: through conduction, the heat transfers from the grout to the outer pipe wall and from the outer to the inner pipe wall, and by convection from the inner pipe wall to the circulating water. The model was implemented in MATLAB using an ordinary differential equation (ODE) solver. The results reveal that the acceptable range of the water velocity for Oakland University’s GHE was between 0.35 and , which ensured that the heat pump system delivered the proper temperature to provide the Human Health Building (HHB) with a comfortable temperature regardless of the season. The suggested water velocity ranges in vertical single U-tube pipes with diameters of De , De , and De  are between 0.33 and  to , and 0.38 to , respectively. In the future, the study anticipates controlling this nonlinear system at several operational points, controlling each point separately, and switching between these controllers using the single controller block to control it more effectively along its trajectory.

In this chapter, the analysis of the transient responses of visco-thermoelastic material in the context of two temperature fractional generalized thermoelastic diffusion models is presented. Here, a thermoelastic plate that is initially kept traction-free at a uniform temperature and subjected to thermal as well as mechanical loadings on both of its surfaces is considered for the study. The basic equations and constitutive relations governing the problem are solved in the Laplace-Fourier transformed domain using boundary restrictions. The expressions thus obtained in the transformed domain are too complex to invert analytically. Hence by applying the numerical inversion technique, results of physical quantities are obtained in the original domain using the physical data of copper material. The impact of viscosity, two temperature, and fractional order parameters on various physical quantities is presented graphically. The outcome of this work underlines that viscosity parameters have a significant influence on the field quantities, and increasing two temperature parameter or decreasing the fractional order parameter leads to their smoother distribution.

This chapter focuses on a theoretical idea to design metallic nanostructures, that support surface plasmon, based on an analogy with the quantum principle of multiple hybridization that leads to atomic dressed states.

Surface plasmon hybridization opens up new perspectives in the light manipulation at the nanoscale and related applications in nanophotonics. Several strategies have been pursued to design metallic nanostructures for specific applications such as wave-guiding, spasers, optoelectronics, multiplexing for communications. Here, we study by simulations the strong coupling regime between several surface plasmon polaritons.

Multiple-hybridization between metallic layers inside plasmonic nanocavities displays properties similar to atomic dressed states. We propose to numerically and analytically investigate the case of a multilayer structure composed of stacked metallic (M) and insulator (I) thin films. For a small number of MIM blocks, the system shows discrete hybridization schemes arising from plasmonic strong coupling. When the number of layer increases, multiple and stronger couplings occur and give birth to new modes which merge to form a plasmonic energy continuum. A schematic diagram of modes construction is presented to help the design of vertical nanocavities with specific properties such as plasmonic guiding.

In this paper, the electrochemical method of hydrogen accumulation in the electrodes of nickel-cadmium batteries, depending on their service life, has been investigated. It has been experimentally proven that hydrogen accumulates in batteries electrodes in large quantities and reaches its maximum capacity within about five years. It has been demonstrated that metal hydrides, which are hydrogen compounds, accumulate in the metal-ceramic matrices of sintered oxide-nickel electrodes. The nickel matrix has a gravimetric capacity of 20.3 weight percent and a volumetric capacity of 406 kg m-3 with a relative experimental error of 4%. , it should be noted that none of the hydrogen storage systems that exist today meet the requirements of the US DOE in all criteria. It is the lack of reliable hydrogen storage systems that can compete with the fuel tanks of cars containing gasoline that is the main obstacle to the widespread use of hydrogen energy. The measured gravimetric capacities for metal-ceramic matrices surpass previous measurements for reversible hydrogen storage systems as well as the US Department of Energy's (DOE) requirements for onboard hydrogen storage systems by almost four times. It is concluded that using the electrochemical method of hydrogen accumulation and the thermal runaway process, one can not only achieve all the criteria established by the US DOE for metal hydrides, but also significantly exceed them.

We present a microfluidic platform based on a fiber-optic three-way Mach-Zehnder interferometer (MZI), aimed to measurement of the refractive index (RI) of liquids and characterization of suspended glass particles (cylinders) simultaneously. The measurement principle is based on low coherence interferometry, where the maximum position of the interferogram Gaussian envelope  depends on the optical path difference (OPD) between the measuring and the reference arm of the MZI. An algorithm was developed for calculating the refractive index of liquids and glass particles, as well as for finding the particle diameter from the raw photodetector signals. The physical particle diameter is calculated from the measured particle transit time while passing through the test beam. We found very good agreement between the experimental results and the literature data on the examined liquids refractive index and dimensions and refractive index of suspended particles. The accuracy of the refractive index measurement was about 1 %, mainly determined by the accuracy of position reading of the mechanical scanner. The minimal sample volume can be as small as 1 µl is capable of measuring the refractive index of different liquids and gases and their suspensions simultaneously. The proposed method is attractive for label-free biological, biochemical and chemical sensing because of its high sensitivity and accuracy and  self-calibrating feature.

This article focuses on a novel understanding of the sublayer energy classification.  Assimilation of a point to a sublayer results in the representation of an affine function in an orthonormal frame. This enabled the creation of a graph that integrated all of the known energy level diagrams.  The atom's distinctive graph serves as an energy level diagram that corresponds to all diagrams in the literature. It can serve as a stand-alone example of each idea pertaining to the classification of elements and their electronic structure.

The aim of this work is to develop creative imaginations instead of the classic- al methods, which are ambiguous because of their rather abstract character. The study of an atom's characteristic graph in all of its facets enables the explanation of atomistic concepts. Specific graphs derived from this graph have been used to describe some of the ideas behind the electronic cloud's recomposition.  The characteristic graph of the atom is constructed in an orthonormal axis sys- tem of the type. The concepts have been represented by lines, segments and even points. This has made it possible to draw up tables with orders, periods and even their correlations. By transforming the "abstract" aspect of theoretical concepts into a more "concrete" aspect, this work aids in their better understanding. This eventually makes it easier to learn this fundamental aspect of chemistry. These findings show that the research hypothesis was confirmed.