Derived Hench bioactive glass (BaG) containing boron (B) is explored in this work as it plays an important role in bone development and regeneration. B was also found to enhance BaG dissociation. However, it is only possible to incorporate a limited amount of B. To increase the amount of B in BaG, bioactive borosilicate glasses (BaG-B_x) were fabricated based on the use of the solution-gelation process (sol-gel). In this work, a high B content (20 wt.%) in BaG, respecting the conditions of bioactivity and biodegradability required by Hench, was achieved for the first time. The capability of BaG-B_x to form an apatite phase was assessed in vitro by immersion in simulated body fluid (SBF). Then, the chemical structure and the morphological changes in the fabricated BaG-B_x (x = 0, 5, 10 and 20) were studied. The formation of hydroxyapatite (HAp) layer was observed with X-ray diffraction (XRD) and infrared (IR) spectroscopy. The presence of HAp layer was confirmed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Enhanced bioactivity and chemical stability of BaG-B_x were evaluated with an ion exchange study based on Inductively Coupled Plasma–Optical Emission Spectrometry (ICP-OES) and energy dispersive spectroscopy (EDS). Results indicate that by increasing the concentration of B in BaG-Bx, the crystallization rate and the quality of the newly formed HAp layer on BaG-B_x surfaces can be improved. The presence of B also leads to enhanced degradation of BaGs in SBF. Accordingly, BAG-B_x can be used for bone regeneration, especially in children, because of its faster degradation as compared to B-free glass.

To support the grid system with high power quality from photovoltaics (PVs) and reduce the partial shading condition (PSC) effect of the PV system, as well as the mismatch power issue, in this study, we present a simple single-phase, nine-level cascade inverter architecture for photovoltaic (PV) systems with a minimum number of power components and passive parts. This reduction in the number of switches decreases the switching losses and the number of driving circuits, which causes a reduction in the complexity of the control circuit and hence reduces the cost and size. The suggested inverter shows a lower output voltage total harmonic distortion (THD) and unity power factor. In addition, this inverter’s control and switching techniques are far simpler than those of recently published designs. To evaluate the performance of the proposed inverter, we performed a comparison of the cascaded multilevel inverter (CMLI) topology, which required recent cascade topologies with the same nine voltage levels. The comparison depends on parameters such as the number of components (diode and capacitors) and the number of active switches in the inverter, in addition to total harmonic distortion. MATLAB/Simulink models for a grid-tied solar system PV application driven by the proposed nine-level inverter were built for design and validation.

The emergence of IoT applications has risen the security issues of the big data sent by the IoT devices. The design of lightweight cryptographic algorithms becomes a necessity. Moreover, elliptic curve cryptography (ECC) is a promising cryptographic technology that has been used in IoT. However, connected objects are resource‐constrained devices, with limited computing power and energy power. Driven by these motivations, we propose and develop a secure cryptographic protocol called CoopECC which leverages the organization of IoT nodes into cluster to distribute the load of cluster head (CH) among its cluster members. This technique proves that it optimizes the resource consumption of the IoT nodes including computation and energy consumption. Performance evaluation, done with TOSSIM simulator, shows that the proposed protocol CoopECC outperforms the original ECC algorithm, in terms of computation time, consumed energy, and the network’s lifespan.

Superconducting magnetic energy storage (SMES) systems are characterized by their high-power density; they are integrated into high-energy density storage systems, such as batteries, to produce hybrid energy storage systems (HESSs), resulting in the increased performance of renewable energy sources (RESs). Incorporating RESs and HESS into a DC bus to obtain a DC microgrid concept is considered a more attractive option for solving system reliability and stability issues. In this paper, we focus on employing SMES systems based on their characteristics of a fast response and high efficiency, which contribute to increased battery lifespan, and reducing the mismatch between the energy supplied by the renewable energy source and the load demand by compensating for the effects of partial shading on the PV system on the DC bus side and the imbalance in loads on the other side of the AC bus. The incremental conductance algorithm (INC) is used for maximum power point tracking (MPPT) in the PV system. Fuzzy logic control (FLC) is proposed for the generation of control signals for the DC–DC chopper used to charge/discharge the SMES coil. Simulations using MATLAB/Simulink were then carried out to assess the proposed models of the (standalone and grid) connection systems.

A smart city’s vehicular communication strategy is important. A significant problem with vehicular communication is scalability. Clustering can help with vehicular ad hoc network (VANET) problems; however, clustering in VANET faces stability problems because of the rapid mobility of the vehicles. To achieve high stability for the VANET, this paper presents a new efficient Eigen-trick-based hypergraph stable clustering algorithm (EtHgSC). This algorithm has a twofold scheme for stable CH selection. In the first part of the proposed scheme, the cluster generation is handled using an improved hypergraph-based spectral clustering algorithm using the Eigen-trick method. The “Eigen-trick” method is used to partition both vertices and hyperedges, which provides an approach for reducing the computational complexity of the clustering. The cluster head (CH) is chosen in the second part, taking into account the requirements for keeping a stable connection with most neighbors. In addition to relative speed, neighboring degree, and eccentricity that are used to select the CH, the vehicle time to leave metric is introduced to increase the CH stability. The grey relational analysis model is used to find each vehicle’s score, and the CH is selected based on the maximum vehicle’s score. The results show the supremacy of our proposed scheme in terms of CH lifetime, cluster member (CM) lifetime, and the change rate of CH. Also, the proposed scheme achieves a considerable reduction in terms of packet delay.