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This paper proposes a new approach for the optimal design of microwave absorbing composites backed by a PEC layer and characterized by frequency dependent permeability and permittivity. The reflection coefficient is expressed as a function of the difference between the absorber hyperbolic input impedance and the free space wave impedance, considering an impinging plane wave with either normal or oblique incidence angle. The impedance matching condition for the selected frequency and incidence angle is solved in terms of literal expression of the optimal thickness, which is compared with the one quarter wavelength thickness given by a new accurate expression. The optimal thickness is used for the design of microwave absorbers made by dielectric-magnetic and dielectric composite materials. The frequency spectra of the absorber input impedances and reflection coefficients are computed in the frequency range from 2 GHz up to 18 GHz and for an incidence angle ranging between 0° and 30°. The obtained results prove the validity of the literal expression of the composite optimal thickness which explicitly shows the crucial parameters for the absorbing performances, obscured in common numerical procedures.

In this work, novel flexible metal-free polymeric cathode electrodes are developed through a cost-effective procedure for low energy generation applications. For this purpose, a nanocomposite film made of poly vinylidene fluoride (PVDF) filled with graphene nanoplatelets (GNPs) is produced through an easy process, without the use of any chemical or physical doping agent. The fabricated PVDF/GNP nanocomposite films are morphologically and chemically characterized and their applicability as polymeric electrodes is investigated through electrochemical tests.

Over the past few years, remote monitoring based services are developing in different domains such as traffic monitoring, healthcare, emergency management and environment protection. These applications presuppose the system ability to manage a lot of data coming from different systems. In this paper, the design of a module for remote and real-time monitoring of environmental parameters is indicated. The conceived architecture is based on the microservice paradigm and adopts the 2G data communication network.

The growing rhythm of the modern economy forces companies to constantly introduce new solutions, resulting in innovating the market. Nowadays, the vast majority of businesses are determined to implement product, technical, technological and organizational innovation. Enterprises are focused on creating value for the customer, who is becoming more aware and demanding in terms of increased customer requirements relating to lead time delivery services, product availability and reliability. The newest solutions such as Internet of Things, Big Data and Industry 4.0 create opportunities to meet the needs and to contribute to the development of logistics and supply chains management. In this paper we analyse the possibility of utilizing Business Process Management techniques, Standard Methodology, Artificial Intelligence techniques (AI) and Decision Support Systems (DSS) in the management of business processes for supporting business processes optimization with a centred approach at supply chains under the usage of the business process lifecycle.

An innovative effective-medium model of ID-periodic multilayer coatings is developed by applying the transmission line method. Each period consisting of several layers with subwavelength thickness in the nanometer range is modelled as a homogeneous medium characterized by an effective complex conductivity and unit relative permeability. The resulting effective single layer (ESL), having the same total thickness of the multilayer laminate, is represented by a transfer matrix given by the product of the transmission matrices of the periods composing the structure. The effective homogeneous model is used to compute the shielding effectiveness of ID-periodic photonic-band-gap transparent coatings made by alternating layers of silver and zinc oxide films in the frequency range up to 10 THz. The good accuracy of the results obtained using the ESL is demonstrated by comparison with the results computed by means of the rigorous multilayer formulation.

A porous graphene based PVDF aerogel is produced through a cost-effective procedure, for possible application as sweat sensor. The aerogel samples were characterized in terms of porosity, density, morphological and electrical properties through high-resolution scanning electron microscopy (HR-SEM) and time-monitoring of the sample dc electrical resistance.

This paper presents a smart system based on Low Power Wide Area networks for a remote monitoring of technological room in unstaffed railway stations. The paper aim is the design of an efficient network scheme characterized by improved performance compared with the standard solution. Adopting an innovative smart System Control Strategy and a custom network topology, good results are reached in terms of reliability without increasing the amount of devices with respect the standard scheme.

The electromagnetic field radiated by Cu-graphene interconnects is predicted in the frequency domain using the equivalent single conductor formulation, and it is compared with the field radiated by a single-wall carbon nanotube (SWCNT) bundle interconnect having the same cross section. The effect of the frequency, of the configuration, of the graphene, and SWCNT mean free paths is investigated. The scope is to predict the risk of electromagnetic interference against nearby components and devices, and to define the most critical conditions.

A new adaptive terahertz absorbing screen providing a reflection coefficient lower than −10 dB in the frequency range 0.6–2.2 THz and with total thickness around 70 μm is proposed. The designed Salisbury screen, backed by a perfect electric conducting plate, consists of a first graphene layer as lossy sheet and two spacers made of polyethylene terephthalate (PET), separated by a tunable graphene/SiO2 laminate (GL). An electrostatic field up to 0.06 V/nm is applied across the GL in order to tune the electrical conductivity of the graphene layers, with the aim of minimizing the screen total reflection coefficient. A design procedure based on the transmission line method is proposed and a parameter sensitivity analysis of the reflection coefficient is carried out. The influence of the carrier charge mobility and of the number of graphene sheets composing the GL is investigated, considering different values of the electrostatic field in the frequency range 0.1–5 THz.

Closed-form expressions describing the tensorial conductivity of an electrically or magnetically biased monolayer graphene are provided in order to highlight the low-gigahertz gyrotropic, shielding and sensing properties. The longitudinal and transverse (Hall) conductivities are given as explicit functions of the fundamental electromagnetic quantities, i.e. the magnetic and electric field bias, B 0 and E 0 , and the carrier charge mobility μ The developed simple expressions of the components of the electric field transmission coefficient are utilized to compute the polarization rotation angle θ and the shielding effectiveness (SE), in case of normally incident plane wave. The dependence of θ on B 0 is investigated, and the magnetic field value providing the maximum θ is found. The simulation model is applied to compute gyrotropic, SE and sensing performances of the biased graphene sheet at low-gigahertz regime. Moreover, exploiting the sensing properties of the biased graphene sheet, the measured value of θ is used to evaluate B 0 , E 0 and μ.

This paper presents an innovative Bluetooth Low Energy indoor localization system useful to improve energy efficiency in buildings. A tracking system to localize people within a building has been developed using a novel infrastructure system and a custom signal processing method. Knowledge whether people are present or not in every room enables the automatic switching-off of lighting and heating/cooling in empty room increasing the energy efficiency of building system. The implemented method achieves performance comparable to that of a traditional Bluetooth Low Energy indoor location system, nevertheless fewer devices are used. As a result, the cost of installation in existing building decreases.

An innovative lightweight and flexible multilayered screen made by electrically doped graphene sheets laminated with thin films of polyethylene terephthalate (PET) is proposed. The shielding effectiveness (SE) of the screen is computed in the low GHz frequency range assuming that the graphene/PET multilayer is modelled as an equivalent single-layer shield having an effective conductivity. A rigorous simulation model is utilized to define the maximum frequency of applicability of the proposed approximate formulation of the SE. A SE of 40 dB is obtained in a wide frequency range, up to more than 200 GHz, with a screen consisting of 24 graphene layers electrically doped and having a total thickness of 0.69 µm.

In recent years, several studies have demonstrated the strong cytotoxicity toward bacteria of graphene-based materials, suggesting their use as antimicrobial agents. The objective of this study was to evaluate the antibacterial activity against Streptococcus mutans, the principal microbiological agent in the etiology of dental caries, of two types of graphene nanoplatelets (GNPs), characterized by different thickness and lateral dimensions of the flakes. The antimicrobial properties of GNPs were valued on some plaque and saliva samples extracted from children with dental caries. Our results show that the killing effect of GNPs on S. mutans cells is both lateral size and thickness dependent. In fact, lower thickness and smaller size GNPs exhibit stronger antibacterial activity than larger and thicker ones. Scanning electron microscopy analysis revealed that GNPs interact strongly with cells. This study suggests that GNPs may be highly effective against S. mutans and therefore caries.

Innovative multilayered screens made of laminated graphene sheets, with SiO $_{2}$ as interlayer, over a glass substrate are proposed as electrically-tunable electromagnetic shields at terahertz. The shielding effectiveness (SE) modeling is developed applying the transmission line method in a reverberating environment (i.e., with the screen surface illuminated by an infinite set of plane waves impinging with all possible propagation directions), which is of particular relevance in electromagnetic compatibility (EMC) studies. A new equivalent single layer (ESL) model of the graphene/SiO $_{2}$ laminate (GL) is also proposed in order to provide a simple computationally-efficient method for the EMC design of GL shielding configuration via numerical EM tools. The approximate model is validated by comparison with the results obtained applying the exact one. The sensitivity analysis of the SE in reverberating environment is performed in the frequency range up to several tens of terahertz with respect to: the electric field bias of the graphene sheets, affecting their chemical potential level through an electrostatic carrier doping; the relaxation time characterizing the electron transport in graphene; the thickness of the SiO $_{2}$ interlayers. Finally, the SE computed for different shielding configurations against a plane wave with normal or oblique incidence is compared with the one obtained in a reverberating environment in order to highlight the most significant differences at terahertz frequencies.

Numerous inquiries from K-12 educators across the state of New Jersey have indicated that defining and implementing Science, Technology, Engineering, and Mathematics (STEM) education has become a challenge to the K-12 education sector. Many of these K-12 educators approach STEM disciplines as if each one exists in isolation from the others and they do not integrate the content and skills of the disciplines that can engage students on many levels. Alternately, they may believe that an engineering experience and/or robotics, i.e. an isolated project, can be considered a STEM program. Our responses have focused on STEM education as an interdisciplinary area of study that integrates the four disciplines rather than achieving skills and knowledge independently in each subject area. A STEM program should also provide students experiences in problem-solving, analytical, critical thinking, teamwork, and communication skills. As a result, students should possess the ability to apply, synthesize, and evaluate their knowledge of how the world works within and across the disciplines of science, technology, engineering, and mathematics. This paper describes our approaches with educators that can lead to effective implementation of a STEM program to make connections between the STEM disciplines. Examples of program implementation will illustrate two pathways: 1) Development of an "engineering track" that begins with an introduction to engineering and engineering design as a problem solving method applied to different engineering problems. This course is then followed by a sequence of modules/courses focusing on different areas of engineering of interest to the educators and their students. This program may be developed as a three- or four-year high school track with the senior year culminating in the University freshman college engineering course for which students can earn dual credit. The content of all courses in the sequence are aligned with the content of science and mathematics courses students are taking or have taken in their high school curriculum. 2) Integration of engineering principles and appropriate applications into the science and mathematics courses offered by the school. Here, students can see the parallel nature of the engineering design process, scientific inquiry process, and mathematical problem solving. Regardless of the chosen pathway, our approach also focuses on the three distinct, but interrelated components of teaching and learning: Instruction, Curriculum, and Assessment of student learning. All interrelated activities are described in lesson plans designed to be aligned with these three components into a coherent process and learning experience aligned with the Common Core State Standards (CCSS) and the Next Generation Science Standards (NGSS).

In this work we investigate the shielding properties of graphene-based films, produced by spray casting deposition, which is a cost-effective technique that can be directly scaled to industrial applications. The deposition process is optimized in order to produce uniform films made of well dispersed graphene nanoplatelets (GNP), having thicknesses in the range 3–8 microns. The sheet resistance and the shielding effectiveness up to 18 GHz of films produced using GNP-suspensions at different concentrations are measured and compared with the ones of carbon nanotube (CNT)-based films, produced in the same conditions. The obtained results demonstrate the superior shielding properties of graphene-based films with respect to CNT-ones, mainly due to the bi-dimensional shape of GNPs, which contributes to minimizing the contact resistances among adjacent nanostructures. It is also demonstrated that after a thermal annealing at 250°C, the final measured shielding effectiveness of the produced GNP-film triplicates in linear scale, reaching the value of 30.6 dB.

Terahertz communication technologies are based on the use of a frequency range from 300 GHz up to 3 THz, according to standardization and regulation activities of the IEEE 802.15 IG THz. Graphene, which is characterized by excellent electrical, thermal and mechanical properties, is an attractive choice for EMI shielding applications. New models are proposed for the analysis of the shielding effectiveness of graphene multilayer thin films in the lower THz range taking into account the frequency dependence of the electrical conductivity. Already known models are applied to estimate the optical transmittance. Moreover, transparent substrates coated by graphene multilayer sheets are simulated. The proposed modeling approach is applied to the performance analysis of graphene multilayer thin sheets in the frequency range up to 1 THz.

Graphene films are grown by chemical vapour deposition on copper layer and then transferred onto a silicon substrate, coated with silicon dioxide. The topological characterization of the produced film is performed by atomic force microscopy, and the sheet resistance is measured by applying the four-probe test method. The equivalent single conductor model is then used in order to analyze the signal propagation along a nanointerconnect made with multilayer graphene over silicon dioxide, in a wide frequency range, up to 100 GHz. The comparison of the radio-frequency performances of the nanointerconnect, modeled by using either the measured value of effective resistivity or a theoretical estimation of the p.u.l. resistance, suggests that graphene films grown by chemical vapor deposition are more suitable for application as low frequency electrical interconnections in flexible electronics, than in high-speed integrated circuits.

Smart transmission systems have introduced new possibilities of using topology control process for increasing power system dynamic security. Nowadays, in short term analysis, transmission topology is often treated as static and network reconfiguration is performed only for optimizing power flows and market performance. Modern technological infrastructure have enabled fast communication between power system elements. In this scenario, it is foreseeable that topology control can be exploited in real-time as the last resource for avoiding system collapse. In this paper, a dynamic corrective control strategy based on line switching technique is presented. In particular, the proposed method is based on an algorithm that allows to identify transmission lines that should be switched on/off during transients and the time when the corrective action has to be applied in order to guarantee system stability. The feasibility of this approach is demonstrated through simulations on a detailed representation of the Italian transmission network.

The crosstalk analysis among MWCNTs in a complex bundle is performed in the frequency domain in the range up to 100 GHz. Numerical simulations are performed by using both the multiconductor transmission line (MTL) method and reduced-order equivalent models based on the equivalent single conductor (ESC) approach in order to reduce the complexity of the system. Each MWCNT of the bundle is firstly modeled as an ESC; next, the parallel connected ESCs of the bundle are further represented by only one equivalent conductor. The accuracy of the proposed approximation is assessed and discussed.

The use of novel nanocomposites, consisting in polymeric-based system filled with graphite-nanoplatelets (GNP), is proposed to increase the shielding performance and to reduce the Q of small enclosures excited by impinging plane waves in the gigahertz frequency range. Structure and electrical characteristics of the realized GNP-based composites are described. Absorbing performances of a planar infinite screen made with two layers panel backed on a metallic surface, illuminated by a TM and a TE polarized plane waves, are computed in reverberating conditions. The same absorbing nanostructure is considered to realize the walls of a small-dimensions cubic box with a slot aperture. The full-wave numerical simulations demonstrate that the use of the new material produces resonance damping of microwave electric field and a factor 104 reduction of the Q of a full-metallic enclosure.

The transient shielding performances of small transparent cubic boxes illuminated by an impulsive plane wave, exciting the frequency range up to several gigahertz, are analyzed by applying an 3D full wave method. The box is made by transparent polycarbonate walls coated with a thin nanostructured transparent film, consisting of alternating thin layers of metal (Ag) and dielectric (TiO 2 ) materials, and contains a total of 68 nm of silver. A GNP-based nanocomposite absorber, custom designed and tuned on the first resonance frequency of the enclosure is used to panel the inside of the box in order to dump unwanted reflections.

This paper investigates the shielding effectiveness properties of different types of carbon fiber reinforced composites (CFRC), typically used aboard air-vehicles, in the frequency range from 100 kHz up to 18 GHz. Both single-layer and multilayer, unidirectional or woven, CFRCs are analyzed, and the critical issue concerning sample preparation is addressed. The study is aimed at defining an effective single layer model of the CFRC laminate, characterized by an effective frequency-dependent electrical conductivity, which is extracted from the measured shielding effectiveness.