Development of q-Rung Orthopair Trapezoidal Fuzzy Einstein Aggregation Operators and Their Application in MCGDM Problems

Compared to previous extensions, the q-rung orthopair fuzzy sets are superior to intuitionistic ones and Pythagorean ones because they allow decision-makers to use a more extensive domain to present judgment arguments. The purpose of this study is to explore the multicriteria group decision-making (MCGDM) problem with the q-rung orthopair trapezoidal fuzzy (q-ROTrF) context by employing Einstein t-conorms and t-norms. Firstly, some arithmetical operations for q-ROTrF numbers, such as Einstein-based sum, product, scalar multiplication, and exponentiation, are introduced based on Einstein t-conorms and t-norms. Then, Einstein operations-based averaging and geometric aggregation operators (AOs), viz., q-ROTrF Einstein weighted averaging and weighted geometric operators, are developed. Further, some prominent characteristics of the suggested operators are investigated. Then, based on defined AOs, a MCGDM model with q-ROTrF numbers is developed. In accordance with the proposed operators and the developed model, two numerical examples are illustrated. The impacts of the rung parameter on decision results are also analyzed in detail to reflect the suitability and supremacy of the developed approach

An Approach for Estimating the Reliability of IGBT Power Modules in Electrified Vehicle Traction Inverters

The reliability analysis of traction inverters is of great interest due to the use of new semi-conductor devices and inverter topologies in electric vehicles (EVs). Switching devices in the inverter are the most vulnerable component due to the electrical, thermal and mechanical stresses based on various driving conditions. Accurate stress analysis of power module is imperative for development of compact high-performance inverter designs with enhanced reliability. Therefore, this paper presents an inverter reliability estimation approach using an enhanced power loss model developed considering dynamic and transient influence of power semi-conductors. The temperature variation tracking has been improved by incorporating power module component parameters in an LPTN model of the inverter. A 100 kW EV grade traction inverter is used to validate the developed mathematical models towards estimating the inverter performance and subsequently, predicting the remaining useful lifetime of the inverter against two commonly used drive cycles

Dangling and hydrolyzed ligand arms in [Mn3] and [Mn6] coordination assemblies: synthesis, characterization, and functional activity

Two flexible, branched, and sterically constrained di- and tripodal side arms around a phenol backbone were utilized in ligands H3L1 and H5L2 to isolate {Mn6} and {Mn3} coordination aggregates. 2,6-Bis{(1-hydroxy-2-methylpropan-2-ylimino)methyl}-4-methylphenol (H3L1) gave trinuclear complex [Mn3(μ-H2L1)2(μ1,3-O2CCH3)4(CH3OH)2](ClO4)2·4CH3OH (1), whereas 2,6-bis[{1-hydroxy-2-(hydroxymethyl)butan-2-ylimino}methyl]-4-methylphenol (H5L2) provided hexanuclear complex [Mn6(μ4-H2L2)2(μ-HL3)2(μ3-OH)2(μ1,3-O2CC2H5)4](ClO4)2·2H2O (2). Binding of acetates and coordination of {H2L1}− provided a linear MnIIIMnIIMnIII arrangement in 1. A MnIII6 fused diadamantane-type assembly was obtained in 2 from propionate bridges, coordination of {H2L2}3–, and in situ generated {HL3}2–. The magnetic characterization of 1 and 2 revealed the properties dominated by intramolecular anti-ferromagnetic exchange interactions, and this was confirmed using density functional theory calculations. Complex 1 exhibited field-induced slow magnetic relaxation at 2 K due to the axial anisotropy of MnIII centers. Both the complexes show effective solvent-dependent catechol oxidation toward 3,5-di-tert-butylcatechol in air. The catechol oxidation abilities are comparable from two complexes of different nuclearity and structure

The prevalence, preventive measures and economic impact of pandemic COVID-19 in India : the initial phase

The novel coronavirus (SARS-CoV-2) is posing a serious threat to the mankind with its massive infection rate and potentially fatality. A total of 212 countries have been infected within the 112 days of fi rst report causing 2 314 621 confi rmed cases and 157 847 deaths worldwide. India, the country which is already battling with poverty, malnutrition and high population density is also at the second stage of coronavirus transmission. The situation is worsening and the attention has focused on the prevalence and preventive measures to be taken to protect 1.35 billion people of the largest democratic country of the world. In this review, a study has been designed to evaluate the prevalence, transmission, clinical symptoms, and preventive measures to control the community transmission of this fatal disease. The initial impact of coronavirus disease (COVID-19) outbreak on Indian economy has also been dealt with. This study reviews and summarizes the main points of the epidemic in India until the end of April 2020

Three new hydrochlorothiazide cocrystals: Structural analyses and solubility studies

YesHydrochlorothiazide (HCT) is a diuretic BCS class IV drug with poor aqueous solubility and low permeability leading to poor oral absorption. The present work explores the cocrystallization technique to enhance the aqueous solubility of HCT. Three new cocrystals of HCT with water soluble coformers phenazine (PHEN), 4-dimethylaminopyridine (DMAP) and picolinamide (PICA) were prepared successfully by solution crystallization method and characterized by single crystal X-ray diffraction (SCXRD), powder X-ray diffraction (PXRD), fourier transform –infraredspectroscopy (FT-IR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Structural characterization revealed that the cocrystals with PHEN, DMAP and PICA exists in P21/n, P21/c and P21/n space groups, respectively. The improved solubility of HCT-DMAP (4 fold) and HCT-PHEN (1.4 fold) cocrystals whereas decreased solubility of HCT-PICA (0.5 fold) as compared to the free drug were determined after 4 h in phosphate buffer, pH 7.4, at 25 °C by using shaking flask method. HCT-DMAP showed a significant increase in solubility than all previously reported cocrystals of HCT suggest the role of a coformer. The study demonstrates that the selection of coformer could have pronounced impact on the physicochemical properties of HCT and cocrystallization can be a promising approach to improve aqueous solubility of drugs

Performance Evaluation and State-of-Health (SOH) Monitoring of Electric Motor Drive Used for Electric Vehicle Propulsion

The move towards electrified transportation has revived several key attributes of an electromechanical drive system (EMDS) regarding reliability, cost, and power density. One of the most critical components of an EMDS is the inverter, accounting for almost 50% of the drive cost. With the advent of semiconductor technology, it has witnessed evolutions in various aspects such as circuit topology, control schemes, and reliability assessment. However, accelerated consolidation of the electric vehicle (EV) as a mainstream automotive technology still emphasizes more aggressive inverter designs with predictive monitoring for the next generation of EVs. This work presented in this dissertation, hence, focuses on modeling an advanced inverter with improved efficiency and reliability. First, the state-of-the-art electric motor drive topologies are analyzed using drive cycle-based vehicle dynamics model for understanding steady-state and transient performance characteristics. A unique co-simulation method has been developed for this analysis to incorporate harmonics interferences due to drive switching transient and manufacturing constraints. The developed co-simulation method analyzes conventionally used inverter topologies with immensely used silicon (Si) and advanced wide bandgap (WBG) based devices comparing efficiency, power density, cost, and weight. A comprehensive analytical model of an automotive inverter has been developed with electrical and thermal characteristics. Correspondingly, a finite element-based machine model is developed to considering parameter variation such as winding resistance, inductance, and flux linkage due to design constrains. Further improvement is achieved in developing machine model with online parameter estimation using non-invasive evolutionary algorithm. The analysis shows a great performance boost with WBG devices in a conventional inverter topology and improved power density. Nevertheless, the packaging technology of the WBG devices is very expensive due to the complexity in heat distribution, smaller form factor and limited knowledge on matrix formation of semiconductor chips as compared to high power density Si based packaging technology. Additionally, the comparative analysis shows that this technology is yet to be modified for advanced voltages. Thus, a novel hybrid multi-level inverter and nine-switch inverters are proposed with a combination of Si-based and WBG based devices. The designed inverter model forms a unique combination of available WBG and Si-based devices to operate at high voltage condition with reduced cost. Also, the proposed inverter topology uses extended bandgap and high electro mobility towards reduced switching loss, which leads to increase in lifetime. However, some other factors such as temperature dissipation have a significant effect on the lifetime of an inverter depending on the design configuration and need to be incorporated for long time performance analysis. Therefore, in this dissertation a novel online state-of-health monitoring approach has been developed to identify the lifetime of an inverter power module towards improved design configuration. The approach contains an advanced power loss calculation scheme of the drive switching and conduction states considering steady-state and transient switching stages with the influence of parasitic elements. Subsequently, a novel thermal network model is developed for accurate temperature tracking towards accurate heat distribution through the power module layers. This model enhances the accuracy of the temperature tracking with a three-dimensional thermal network model considering semiconductor device cross-coupling area. In addition, an iterative process has been developed for constant estimation of thermal impedances considering material degradation. To identify material degradation, a novel condition monitoring model has been developed with packaging material properties and geometric information. The model contains a modified cycle counting method for number of temperature cycles identification in an online condition. Considering the number of temperature cycles, the total stress is calculated, incorporating the power modules internal geometry, and temperature coefficient mismatch. Consequently, novel bond-wire fault detection and solder fatigue identification and classification models have been proposed using semiconductor electrical and thermal parameters. The developed model analyzes the material degradation and its impact on the semiconductor electrical and thermal characteristics to determine the fault location. Additionally, the developed model observes the parameter changes with the fault propagation. Further recommendations for model improvement, and future work is summarized towards the end of the dissertation

A convenient synthesis of 4-diarylmethyl-, 4-(α-hydroxy-α-aryl/naphthyl)methyl- and 4-(benzoyl/naphthanoyl)-1-(2<i>H</i>)-phthalazinones from ninhydrin

595-603Refluxing of 2,2-diaryl-1,3-indanediones in hydrazine hydrate for a brief period affords 4-diarylmethyl-1-(2H) phthalazinones in very high yield. A series of 4-(α-hydroxy-α-aryl/naphthyl)methyl- and 4-(benzoyl/naphthanoyl)-1-(2H) phthalazinones also have been synthesized simply by stirring 2-hydroxy-2-aryl/naphthyl-1,3-dioxoindanes in hydrazine hydrate (99%) at room temperature in very high yields. All the ninhydrin adducts, 2,2-diaryl-1,3-indanediones and 2-hydroxy-2-aryl/naphthyl-1,3-dioxoindanes are prepared by stirring ninhydrin and the appropriate aromatic hydrocarbons in acid medium

Theoretical studies of the acid-catalyzed condensation of ninhydrin with aromatic compounds

2212-2216Semiempirical quantum chemical methodology (AM1) has been employed to find out the potential energy (P.E.) surface for the acid-catalyzed condensation of ninhydrin with phenol. The AM1/RHF computed activation enthalpies (ΔH#) of the multi-steps chemical process show that the acid catalyzed arylation of ninhydrin should take place smoothly at room temperature, very much consistent with the experimental results. NMR and crystallographic studies show that the monoarylatedninhydrin adducts from phenols preferably remain in intramolecular hemiketal form. AM1/RHF computed heats of formation in some representative cases also favour such intramolecular hemiketal formation