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Poly(ethylene terephthalate) (PET) is a key component of many global plastic products; however, concerns regarding the global accumulation of plastic debris have motivated the development of recyclable and degradable plastics. Thus, we focus on preparing polymers from starting materials that are derived from plastic waste (Control PET), and we then compare the thermomechanical, optical, and end-use properties of the materials to their control plastic counterparts. We prepared different polymers (Recycled PET) from a set of tailored reaction conditions that were refined based on a series of iterative structure–property evaluations. For instance, we quantified the glass transition and melting temperatures of the resultant polymers, and these were benchmarked against those of Control PET plastics. We established the mechanical properties of the Control PET sample and compared them to those of the polymers synthesized from starting materials. The Recycled PET showed excellent performance, maintaining nearly all (around 92%) of the control’s ultimate tensile strength and storage modulus (E′). The Recycled PET exhibited stress relaxation behavior due to the presence of activated ester groups within the polymer chains. Hydrolytic depolymerization breaks Recycled PET down into its basic components, enabling it to be recycled again and again, reducing reliance on control materials. Therefore, this work offers insights into a design strategy for PET, considering its ease of synthesis, abundant precursor availability, and promising end-use properties.

Although the reactivity of five-coordinate end-on superoxocopper(II) complexes, CuII(η1-O2•–), is dominated by hydrogen atom transfer, the majority of four-coordinate CuII(η1-O2•–) complexes published thus far display nucleophilic reactivity. To investigate the origin of this difference, we have developed a four-coordinate end-on superoxocopper(II) complex supported by a sterically encumbered bis(2-pyridylmethyl)amine ligand, dpb2-MeBPA (1), and compared its substrate reactivity with that of a five-coordinate end-on superoxocopper(II) complex ligated by a similarly substituted tris(2-pyridylmethyl)amine, dpb3-TMPA (2). Kinetic isotope effect (KIE) measurements and correlation of second-order rate constants (k2’s) versus oxidation potentials (Eox) for a range of phenols indicates that the complex [CuII(η1-O2•–)(1)]+reacts with phenols via a similar hydrogen atom transfer (HAT) mechanism to [CuII(η1-O2•–)(2)]+. However, [CuII(η1-O2•–)(1)]+performs HAT much more quickly, with its k2for reaction with 2,6-di-tert-butyl-4-methoxyphenol (MeO-ArOH) being >100 times greater. Furthermore, [CuII(η1-O2•–)(1)]+can oxidize C–H bond substrates possessing stronger bonds than [CuII(η1-O2•–)(2)]+is able to, and it reacts with N-methyl-9,10-dihydroacridine (MeAcrH2) approximately 200 times faster. The much greater facility for substrate oxidation displayed by [CuII(η1-O2•–)(1)]+is attributed to it possessing higher inherent electrophilicity than [CuII(η1-O2•–)(2)]+, which is a direct consequence of its lower coordination number. These observations are of relevance to enzymes in which four-coordinate end-on superoxocopper(II) intermediates, rather than their five-coordinate congeners, are routinely invoked as the active oxidants responsible for substrate oxidation.

The multiport autonomous reconfigurable solar (MARS) power plant is a promising solution to integrate renewable resources and energy storage systems into the alternating current (ac) power grid and an high-voltage direct current (HVdc) link. In the MARS system, various input power sources are connected to the individual submodules (SMs) through direct current (dc)–dc converters. However, the presence of external power sources can result in unbalanced capacitor voltages of SMs, thereby violating stability constraints under multiple/diverse operating conditions. This article aims to address the gap by accurately determining the stability boundary of the MARS system. As such, a novel machine learning (ML)-assisted energy balancing control (EBC) criterion is proposed. In conjunction with a refined EBC, this approach ensures balanced capacitor voltages across various types of SMs, significantly enhancing the overall system efficiency. The proposed EBC criterion effectively controls EBC activation and deactivation, achieving remarkable accuracy. Both power systems computer aided design (PSCAD)/electromagnetic transients including direct current (EMTDC) simulations and control hardware-in-the-loop (cHIL) tests are conducted to validate the feasibility and efficiency of the proposed method. By combining the EBC and ML-assisted EBC criterion, efficient energy management is achieved for systems featuring multiple input power sources, such as MARS. This approach enables the system to fully exploit its potential across an expanded operational range while upholding high-efficiency standards.

Nonconjugated open-shell molecules are promising in a host of organic electronic and spintronic applications due to their abilities to conduct charge and provide magneto-responsive behavior. These properties generally arise due to the radical moieties present in their molecular design. Crystalline materials contain highly ordered molecular packing; this facilitates charge transport and often useful optical properties. In addition, liquid crystalline (LC) materials can exhibit structural transitions due to applied stimuli. Here, the relationship between the crystalline and LC structures and the resultant charge and spin transport properties is detailed for a class of 2,2,6,6-tetramethyl-1-piperidinyloxyl (TEMPO) benzoates with systematically tailored molecular structures. Specifically, five distinct molecules were synthesized by using a one-step esterification reaction. Of these five materials, three displayed LC behavior with distinct mesophases, while two formed single crystals with ordered molecular packing. During the evaluation of the materials in testbed devices, one of the single crystalline materials exhibited a room temperature conductivity of ∼15.6 S m–1, along with a 100% magnetoresistance at 10 K with a field strength of 2 T. In this way, the relationships between molecular design and the end-use magneto-responsive charge transport were established for these emerging radical materials.

Detection of bad data from measurement sensors and bad commands from control centers need to be carried out to avoid instabilities within large power electronics systems. Towards the same, in this paper, model and data driven methods are proposed to identify anomalies in measured data and commands received by large power electronics systems. The large power electronics system considered in this paper is a multi-port autonomous reconfigurable solar power plant (MARS), which consists of photovoltaic (PV) and energy storage systems (ESSs) that connect to high-voltage direct current (HVdc) system and transmission ac power grid. The proposed algorithms in the MARS power plant to detect bad data from measurements and bad commands from control centers are evaluated in simulations and hardware-in-the-loop (HIL) tests. It has been observed that the proposed algorithms are able to detect bad measurements and commands in all the use cases evaluated.

Multi-port autonomous reconfigurable solar power plant (MARS) provides an attractive alternative to connect photovoltaic (PV) and energy storage systems (ESSs) to high-voltage direct current (HVdc) links and high-voltage alternating current (ac) grids. In this paper, a unique hierarchical control system of MARS is proposed and evaluated. To evaluate the control system and associated algorithms in early-stage research of complex architectures like MARS, it is important to develop unique suitable hardware-in-the-loop (HIL) platforms. In this paper, the HIL platforms for MARS to evaluate the performance of the hierarchical control system and the control algorithms implemented are presented. They help with the design process of control systems. The real-time simulation models and algorithms that are utilized for MARS in the HIL platforms are also discussed in the paper. The HIL experiments of the control system of MARS showcase the capability to provide continuity of operation under faults and frequency support to the power grid during loss of generation. They also showcase the stability of the proposed hierarchical control system of MARS.