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Synthesis of core‐modified 28π non‐fused hexaphyrin is reported. The optical and 1H NMR spectral analysis reveals the non‐aromatic nature of the macrocycle in its freebase form at 298 K. However, the non‐aromatic nature of the macrocycle remains unaltered upon lowering the temperature. The structural elucidations for the freebase macrocycle also justify the non‐aromaticity of the freebase 8, where the thiophene units of the 1,2 diphenyl 1,2 dithienyl ethene moiety is deviated maximum from the overall macrocyclic framework. Protonation on the imino pyrrolic nitrogens results in single–crystal X‐ray structures of 8 which show essential distortion in macrocyclic framework needed for the effective π‐electron delocalization, attaining Möbius aromaticity. The Nucleus Independent Chemical Shift (NICS) values for the freebase and protonated macrocycles are −2.0 ppm and −5.6 ppm. The Anisotropy Induced Current density shows the clockwise delocalization of current density vectors. Overall, the spectral, structural and theoretical analysis suggests nonaromatic in freebase and Möbius aromatic nature of the protonated hexaphyrin. [ABSTRACT FROM AUTHOR]

This study introduces a bidirectional power sharing scheme between an ac electric utility and a dc microgrid. These two are connected together through an interlinking converter (IC) and a dual active bridge (DAB). The proposed control scheme allows predefined amount of power to be supplied from the ac to dc side or the other way around. The DAB is connected at the dc side of the IC and it controls the bidirectional power flow. The dc microgrid contains dc-dc converters, where boost converters are used with the sources and buck converters are used to supply loads. These dc-dc converters and the DAB are controlled by state feedback with integral control in a linearised discrete domain. The DAB linearisation and control law are presented in detail. The dc microgrid is controlled by conventional V-P droop where the power from/to the ac side is considered as negative/positive load. Detailed simulation results are presented to validate the proposal. Also some hardware results are included that support the findings. [ABSTRACT FROM AUTHOR]

This study introduces a bidirectional power sharing scheme between an ac electric utility and a dc microgrid. These two are connected together through an interlinking converter (IC) and a dual active bridge (DAB). The proposed control scheme allows predefined amount of power to be supplied from the ac to dc side or the other way around. The DAB is connected at the dc side of the IC and it controls the bidirectional power flow. The dc microgrid contains dc–dc converters, where boost converters are used with the sources and buck converters are used to supply loads. These dc–dc converters and the DAB are controlled by state feedback with integral control in a linearised discrete domain. The DAB linearisation and control law are presented in detail. The dc microgrid is controlled by conventional V‐P droop where the power from/to the ac side is considered as negative/positive load. Detailed simulation results are presented to validate the proposal. Also some hardware results are included that support the findings. [ABSTRACT FROM AUTHOR]

An efficient and straight forward synthesis of 2‐substituted benzo[d]thiazole derivatives has been accomplished using a catalyst combination of p‐toluenesulfonic acid (PTSA) and CuI through one‐pot condensation reaction of 2‐aminothiophenols and β‐oxodithioesters in acetonitrile at 80 °C. Simple experimental procedure, good to excellent yields, mild reaction conditions and broad substrate scope are the salient features of the present protocol. Synthesis of 2‐substituted benzo[d]thiazole derivatives is accomplished by employing 10 mol % of p‐toluenesulfonic acid (PTSA) and 20 mol % of CuI from 2‐aminothiophenols and β‐oxodithioesters in acetonitrile at 80 °C. Mild reaction conditions, good yields, and broad substrate scope are some of the additional features of the protocol. [ABSTRACT FROM AUTHOR]

Syntheses of core‐modified 24π pentaphyrin 7 and 20π homoporphyrin 8 are reported. The freebase form of 7 exhibits optical and 1H NMR spectroscopic behavior corresponding to a 4nπ nonaromatic topology at 298 K. However, upon lowering the temperature to 188 K, 7 exhibits weak aromaticity because of a small conformational change. Protonation of the imine pyrrolic nitrogen atoms results in sharpening of the absorption band with more than 100 nm red shift and two‐fold increase in ϵ values. The 1H NMR spectra show large shielding and deshielding of specific protons accompanied by twisting of pyrrole and thiophene rings from the mean plane of the macrocycle. These observations suggest a major structural change upon protonation. The single‐crystal X‐ray structure of protonated 7 a reveals a severe twisting of the macrocycle, especially at the ethene bridge, and the two thiophene rings adjacent to the ethene bridge are pointed above and below the plane of the ethene bridge (49.07° and 49.08°). The nucleus‐independent chemical shift (NICS) values calculated at the center of the macrocycle for the freebase and protonated derivatives of 7 a and 7 b are −5.6, −8.3 ppm and −5.3, −8.4 ppm, respectively. The anisotropy‐induced current density (AICD) plots suggest a clockwise circulation of π electrons. Taken together, the changes occurring in the optical spectra, 1H NMR spectra, single‐crystal X‐ray structure and NICS calculation reflect a Möbius aromatic topology for protonated 7. However, the homoporphyrin 8 remains nonaromatic both in the freebase and protonated form. Nonaromatic–aromatic: The protonation‐triggered conversion of a core‐modified 24π nonaromatic pentaphyrin (see graphic) to a 24π Möbius aromatic pentaphyrin is described. The aromaticity of the protonated form is revealed by 1H NMR spectroscopy, X‐ray structure analysis and nucleus‐independent chemical shift (NICS) calculations. [ABSTRACT FROM AUTHOR]

This study proposes a decentralised droop control method for guaranteeing precise load sharing among distributed resources in an islanded microgrid. Distributed resources are usually fed through power electronic converters and the switching harmonics produced by them are eliminated by third-order output LCL filters. Output impedance is considered as a major factor for finding exact power-angle droop coefficient in droop design - neglecting this factor can affect the load sharing accuracy. Even though an acceptable active power sharing can be achieved with higher droop gains, increased droop gain may adversely affect the microgrid stability. Here, a modified angle droop control is proposed such that the dependence on the output inductance on the real power sharing is removed. Thus, the lower droop coefficients are sufficient for droop sharing and the system stability is not endangered. It has been assumed that the microgrid is converter-dominated, where a proportional-resonant controller has been utilised for converter switching control. This controller has an outer voltage loop and an inner current loop. A harmonic term has been added to the voltage loop to facilitate more accurate reactive power sharing. Simulation studies are conducted using PSCAD/EMTDC to validate the efficacy of the proposed controller. [ABSTRACT FROM AUTHOR]

This study proposes a decentralised droop control method for guaranteeing precise load sharing among distributed resources in an islanded microgrid. Distributed resources are usually fed through power electronic converters and the switching harmonics produced by them are eliminated by third‐order output LCL filters. Output impedance is considered as a major factor for finding exact power‐angle droop coefficient in droop design – neglecting this factor can affect the load sharing accuracy. Even though an acceptable active power sharing can be achieved with higher droop gains, increased droop gain may adversely affect the microgrid stability. Here, a modified angle droop control is proposed such that the dependence on the output inductance on the real power sharing is removed. Thus, the lower droop coefficients are sufficient for droop sharing and the system stability is not endangered. It has been assumed that the microgrid is converter‐dominated, where a proportional‐resonant controller has been utilised for converter switching control. This controller has an outer voltage loop and an inner current loop. A harmonic term has been added to the voltage loop to facilitate more accurate reactive power sharing. Simulation studies are conducted using PSCAD/EMTDC to validate the efficacy of the proposed controller. [ABSTRACT FROM AUTHOR]

Dielectric spectroscopy (DS) is a non‐invasive, label‐free, and promising technique for measuring dielectric properties of biological cells. Recent developments in microfabrication techniques made it possible to perform DS measurements with minute volume of cell suspensions. However, when the cell size approaches the size of the measurement chamber, especially, for single cell measurements, the analytical models [Maxwell–Wagner and Bruggeman–Hanai (BH) mixture models] to extract cell parameters lose their accuracy. Moreover, variations in the cell position relative to the measurement electrodes decrease the accuracy of the analytical solutions. Impedance spectrum of a typical eukaryotic mammalian cell is generated for different geometrical configurations using finite element. The generated data are fitted to the analytical models and extracted cell parameters are compared with the original values. The results show that BH model works more effectively when chamber to cell radius ratio is <3.5 and chamber height to cell radius ratio is <3. Moreover, it is observed that analytical models estimate cell parameters with major errors when the cells are in the vicinity of the electrodes. However, for high‐volume fraction simulations, the BH model was able to predict cell parameters better even in the vicinity of the electrodes. [ABSTRACT FROM AUTHOR]

The synthesis of fused and nonfused core-modified 40π nonaphyrins are reported. Spectroscopic and X-ray structural studies reveal a twisted figure-eight conformation in the freebase form that is nonaromatic. Structural changes occur, from figure-eight to open extended conformation, upon protonation, thereby adopting 4nπ Hückel antiaromatic character, which is reflected in spectroscopic and theoretical studies. Such a structural change also induces ring inversions of specific heterocyclic rings by 180°. [ABSTRACT FROM AUTHOR]

A new fused core-modified 32π heptaphyrin with Möbius aromatic character is reported. The 1H NMR data indicated a weak Möbius aromaticity at 298 K; however, at 213-183 K, the molecule predominates [4 n]π Möbius conformation with strong diatropic ring current, which was further confirmed by X-ray analysis. The protonation experiment led to preservation of the Möbius aromaticity at 298 K. Nevertheless, the experimental results were further supported by theoretical studies. Overall, this study represents the first example of Möbius aromatic fused core-modified expanded porphyrin. [ABSTRACT FROM AUTHOR]

Low voltage feeders (LVFs) experience several voltage quality (VQ) issues such as voltage drop at network peak periods, voltage rise at middays when high number of rooftop photovoltaic cells (PVs) are existing in the feeder, rapid voltage fluctuations as the results of the clouds effects on the power generation of PVs, and voltage unbalance due to the inherent random characteristics of the single‐phase loads and PVs. This study addresses these problems by proposing the concept of coupling the neighbouring LVFs. Based on this concept, two or more LVFs of the same distribution transformer or different distribution transformers are interconnected to support each other and minimise the VQ problems. First, the performance of LVFs in the existing form is discussed and three approaches of coupling the LVFs are presented. Among the presented techniques, coupling of LVFs through a distribution static compensator (DSTATCOM) at the end of the feeder is proposed and focused as an effective technique with minimal side effects such as power losses and cost. Proper dynamic control methods are also proposed for the DSTATCOM and the performance of such a system is investigated under steady‐state and dynamic conditions via numerical analysis and simulation studies in MATLAB and PSCAD/EMTDC. [ABSTRACT FROM AUTHOR]

A healthy state of life suggests not only a disease‐free condition but also normal psychological functioning and behaviour. To maintain a healthy life, the duration of light exposure is a crucial factor. Perturbation of the standard light–dark cycle (LD: 12 h light‐12 h dark in mice) may result in brain, behavioural and physiological abnormalities. The current study determined the effects of 3 and 5 weeks of constant darkness (DD: 00 h light‐24 h dark) on the behaviour, hormones, prefrontal cortex (PFC) and metabolome of male and female C57BL/6 J mice. We also studied 3 weeks of restoration in LD following 5 weeks of DD exposure. The results revealed that 3 weeks of DD affected male mice more than females, and 5 weeks of DD had a comparable impact on behaviour, hormones and the PFC of male and female mice. After restoration in LD, the DD‐induced changes reverted to time‐matched LD conditions in male and female mice. Furthermore, metabolome analysis corroborated male and female mice's behavioural and molecular kinetics. The present study laid the foundation for understanding how DD affects behaviour and the PFC as a function of (a) time and (b) sex and described the roles of stress and sex hormones, cytokines, neurotrophins and metabolic pathways. [ABSTRACT FROM AUTHOR]

Background: Solitary rectal ulcer syndrome (SRUS) is an uncommon disorder of evacuation. Management of bleeding ulcers is usually unsatisfactory with conventional treatment. Argon plasma coagulation (APC) has been reported to control bleeding; however, it has not been shown to result in ulcer healing. The aim of the present study was to: (i) to investigate the efficacy and safety of APC in controlling bleeding from SRUS; and (ii) to study its efficacy in the healing of ulcer/s. Methods: Twenty-four patients with bleeding SRUS diagnosed on clinical, colonoscopic, and histological findings were randomized to receive either standard care alone (12 patients) or to undergo multiple sessions of APC in addition (12 patients). All patients were followed up to determine ulcer healing. Results: Twenty-four patients with a mean duration of symptoms of 12.6 ± 4.8 months were included. Bleeding was controlled with one ( n = 5) or two sessions ( n = 7) of APC. Reduction in size and depth of ulcer was noted. Eight out of 12 patients who received APC had complete healing of ulcers after four to eight sessions, carried out 2–4 weeks apart. The remaining four patients had a reduction in size and depth of ulcers compared to their pretreatment appearance. All patients were advised to have a high intake of fluids, fiber and laxatives, and to undergo biofeedback and behavior modification therapy in addition to the treatment. Conclusions: APC controls bleeding in patients with SRUS and it also improves the healing of these ulcers. [ABSTRACT FROM AUTHOR]

The article discusses a study which examines the structure and properties of low carbon high-strength steel which was processed thermo-mechanically. The steel was alloyed with Mn, Ni, Mo, Cu and microalloyed with Ti and Nb. Analysis of microstructure showed predominantly lath martensite along with twinned martensite structure at all processing conditions.

A simple protocol for the three-component reaction of 4-hydroxycoumarin, pyrazole (II) and aldehydes to give the title compounds via a tandem Knoevenagel-Michael reaction followed by cyclization. [ABSTRACT FROM AUTHOR]

The pyrrole derivatives include a β-amino acid part and are thus of importance for pharmaceutical investigations. [ABSTRACT FROM AUTHOR]

This paper proposes a power exchange strategy for sustainable microgrids (MGs) of remote areas that have no access to a utility grid. This strategy manages the MG during power deficiencies under a decentralised approach (DA), which is the most probable case for remote MGs due to the lack of communication systems, or a centralised approach if a data communication system is available. Under each approach, a two‐level (internal/external) control is established. The internal support is provided through power exchange with local energy storage while the external support is provided through power exchange with a neighbouring MG, after their temporary coupling. Appropriate conditions and constraints, under which the necessity and possibility of internal/external power exchange can be determined, are defined and formulated. These terms are based on local frequency measurements (for DA) and instantaneous power generation of the dispatchable distributed energy resources (for centralised approach). The dynamic performance of a remote system, composed of two MGs, operating with this strategy is evaluated by simulation studies in PSCAD/EMTDC. Furthermore, the small signal stability of such a system is investigated in MATLAB. [ABSTRACT FROM AUTHOR]

The synthesis of a planar expanded meso porphyrin with an intramolecular para-phenylene-bridged core is reported. The planarity of the octaphyrin macrocycle was confirmed by single-crystal X-ray structural analysis, in which the bridged para-phenylene unit deviated by 27° from the mean macrocyclic plane. Spectroscopic analyses and theoretical calculations suggested that the macrocycle was Hückel aromatic and followed a major [34 π] single-conjugation pathway, which indicated that the bridging para-phenylene unit was not involved in the macrocyclic conjugation. Analysis of the photophysical properties of this system by steady-state absorption/fluorescence spectroscopy and transient absorption spectroscopy revealed moderate enhancement in the parameters of the octaphyrin as compared to its non-bridged octaphyrin congeners, which was attributed to the planarity and rigidity of the macrocycle as imposed by the bridging para-phenylene unit. Preliminary anion-binding studies revealed that the protonated macrocycle bound selectively with chloride ions through N−H⋅⋅⋅Cl hydrogen-bonding interactions. [ABSTRACT FROM AUTHOR]

In this paper, a multi‐objective optimization technique is proposed for the planning of a networked microgrid based on peer‐to‐grid (P2G) and peer‐to‐peer (P2P) energy trading schemes. Two different criteria's including annual profit and energy index of reliability are taken into consideration to form a multi‐objective function. The networked microgrid consists of three individual microgrids containing their own combinations of generation resources, batteries and residential loads. All microgrids are connected together and also to the main grid to meet the energy exchange requirements of P2P energy trading. A cooperative game theory technique based on a particle swarm optimization algorithm is used to model the networked microgrid, and to find the suitable sizes of the players that simultaneously maximize the payoff values of both objective functions. Besides, a comparative analysis is carried out for both P2G and P2P energy trading schemes. The results show that the outcomes are maximum when both criteria are considered in the optimization and P2P energy trading is carried out. The sensitivity analysis is performed on the selected parameters and verified the right change 0.003% and 4.5% in discount rate and electricity prices, respectively. [ABSTRACT FROM AUTHOR]

This study has been undertaken with an aim to investigate the suitability of the deep eutectic solvents (DES)‐based systems for magnetic resonance imaging studies. DESs are used to develop the systems, keeping in mind the fact that these are relatively less toxic than ionic liquids, and hence, DES based magnetic compound is expected to be relatively less toxic than magnetic ionic liquids. In this work, spin–lattice (T1) relaxation measurements are carried out in the binary mixtures of deep eutectic solvent with a paramagnetic component choliniumtetrachloroferrate ([Ch][FeCl4]). Two cholinium ion based DESs, namely ethaline and glyceline have been used for this study. For both ethaline/[Ch][FeCl4] and glyceline/[Ch][FeCl4], T1 is observed to vary significantly with very low concentration of [Ch][FeCl4]. Such an observation can arise due to the high degree of paramagnetic coupling between DESs and [Ch][FeCl4]. The results advocate the suitability of both ethaline/[Ch][FeCl4] and glyceline/[Ch][FeCl4] mixture as a potential T1 contrast agent. Interestingly, when the experiments are carried out in aqueous medium, significant lowering of T1 of water proton with very low concentration of ethaline/[Ch][FeCl4] and glyceline/[Ch][FeCl4] is observed. This study demonstrates that the present systems can act as a suitable T1 contrast agent. [ABSTRACT FROM AUTHOR]

This study proposes a new method for stabilising disturbed power systems using wide‐area measurement and controllable devices. A new control algorithm based on kinetic energy is proposed to be applied on the controllers to improve the first swing stability of power systems following large disturbances while also damping the subsequent inter‐area oscillations. The wide‐area controller is implemented by using the Kalman filter estimation of the area‐based model of the system, to stabilise the inter‐area dynamic and improve the stability margin of the system. The proposed approach is simulated on several test systems and the results show significant improvement in the first swing and damping stability of the test systems. [ABSTRACT FROM AUTHOR]

A hybrid NanoGrid (NG) can be considered as the power supply system, for future community houses. In this study, the operation and control of an NG are presented. The NG consists of an AC bus and a DC bus, interconnected through a tie‐converter (TC). All AC loads and distributed energy resources (DERs) of the community houses are connected to the AC bus while all their DC loads and DERs are connected to the DC bus. The NG has an adequate generation capacity to supply its loads in off‐grid status as well as the capability to exchange power with the grid. The TC exchanges the power between two buses and regulates the voltage in both buses, in the case of off‐grid operation. The NG dynamics, with the proposed structure and developed primary and secondary control algorithms are validated through extensive computer simulations in PSCAD/EMTDC. [ABSTRACT FROM AUTHOR]

A new approach is proposed for obtaining a non‐linear area‐based equivalent model of power systems to express the inter‐area oscillations using synchronised phasor measurements. The generators that remain coherent for inter‐area disturbances over a wide range of operating conditions define the areas, and the reduced model is obtained by representing each area by an equivalent machine. The parameters of the reduced system are identified by processing the obtained measurements, and a non‐linear Kalman estimator is then designed for the estimation of equivalent area angles and frequencies. The simulation of the approach on a two‐area system shows substantial reduction of non‐inter‐area modes in the estimated angles. The proposed methods are also applied to a ten‐machine system to illustrate the feasibility of the approach on larger and meshed networks. [ABSTRACT FROM AUTHOR]

To minimise the number of load sheddings in a microgrid (MG) during autonomous operation, islanded neighbour MGs can be interconnected if they are on a self‐healing network and an extra generation capacity is available in the distributed energy resources (DER) of one of the MGs. In this way, the total load in the system of interconnected MGs can be shared by all the DERs within those MGs. However, for this purpose, carefully designed self‐healing and supply restoration control algorithm, protection systems and communication infrastructure are required at the network and MG levels. In this study, first, a hierarchical control structure is discussed for interconnecting the neighbour autonomous MGs where the introduced primary control level is the main focus of this study. Through the developed primary control level, this study demonstrates how the parallel DERs in the system of multiple interconnected autonomous MGs can properly share the load of the system. This controller is designed such that the converter‐interfaced DERs operate in a voltage‐controlled mode following a decentralised power sharing algorithm based on droop control. DER converters are controlled based on a per‐phase technique instead of a conventional direct‐quadratic transformation technique. In addition, linear quadratic regulator‐based state feedback controllers, which are more stable than conventional proportional integrator controllers, are utilised to prevent instability and weak dynamic performances of the DERs when autonomous MGs are interconnected. The efficacy of the primary control level of the DERs in the system of multiple interconnected autonomous MGs is validated through the PSCAD/EMTDC simulations considering detailed dynamic models of DERs and converters. [ABSTRACT FROM AUTHOR]