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γ‐methylene C(sp3)−H functionalization of linear free carboxylic acids remains a significant challenge. Here in we report a Pd(II)‐catalyzed tandem γ‐arylation and γ‐lactonization of aliphatic acids enabled by a L,X‐type CarboxPyridone ligand. A wide range of γ‐arylated γ‐lactones are synthesized in a single step from aliphatic acids in moderate to good yield. Arylated lactones can readily be converted into disubstituted tetrahydrofurans, a prominent scaffold amongst bioactive molecules. [ABSTRACT FROM AUTHOR]

γ‐methylene C(sp3)−H functionalization of linear free carboxylic acids remains a significant challenge. Here in we report a Pd(II)‐catalyzed tandem γ‐arylation and γ‐lactonization of aliphatic acids enabled by a L,X‐type CarboxPyridone ligand. A wide range of γ‐arylated γ‐lactones are synthesized in a single step from aliphatic acids in moderate to good yield. Arylated lactones can readily be converted into disubstituted tetrahydrofurans, a prominent scaffold amongst bioactive molecules. [ABSTRACT FROM AUTHOR]

Iridium-catalyzed C–H activation and borylation reactions operate under mild conditions that enable easy and atom-economical installation of the versatile boronate ester group in (het)arenes and alkanes. The standard catalytic system for iridium-catalyzed borylation uses [Ir(cod)(OMe)]2 as a precatalyst, a bipyridine type ligand, and B2 pin2 or HBpin as the borylating agent. Initially, a bipyridine-ligated trisboryl–iridium complex is generated that enables the borylation reaction and the regioselectivity is mainly governed by the sterics of substituents present on the ring. As a result, monosubstituted and 1,2-disubstituted arenes give mixtures of isomers. Significant efforts by several research groups have overcome the selectivity issue for directed proximal C–H borylation by introducing a directing group and newly developed ligands. This short review aims to summarize recent elegant discoveries in directed C(sp2)–H and C(sp3)–H borylation by using heterobidentate ligand (P/N–Si, N–B, and N–C) coordinated iridium catalysts. 1 Introduction 2 Iridium-Catalyzed Directed C–H Borylation of C(sp2)–H Bonds 3 Iridium-Catalyzed Directed C–H Borylation of C(sp3)–H Bonds 4 Conclusions [ABSTRACT FROM AUTHOR]

A method of para‐selective borylation of aromatic amides is described. The borylation proceeded via an unprecedented substrate–ligand distortion between the twisted aromatic amides and a newly designed ligand framework (defa) that is different from the traditionally used ligand (dtbpy) for the C−H borylation reactions. The designed ligand framework (defa) has led to the development of a new type of catalytic system that shows excellent para selectivity for a range of aromatic amides. Moreover, the designed ligand has shown excellent reactivity and selectivity for a range of heterocyclic aromatic amides. The identification of key transition states and intermediates using the DFT computations associated with the three regio‐isomeric pathways revealed that the most efficient catalytic pathway with the defa ligand leads to the para borylation while in the case of bpy the borylation at the para and meta sites compete. [ABSTRACT FROM AUTHOR]

A method of para‐selective borylation of aromatic amides is described. The borylation proceeded via an unprecedented substrate–ligand distortion between the twisted aromatic amides and a newly designed ligand framework (defa) that is different from the traditionally used ligand (dtbpy) for the C−H borylation reactions. The designed ligand framework (defa) has led to the development of a new type of catalytic system that shows excellent para selectivity for a range of aromatic amides. Moreover, the designed ligand has shown excellent reactivity and selectivity for a range of heterocyclic aromatic amides. The identification of key transition states and intermediates using the DFT computations associated with the three regio‐isomeric pathways revealed that the most efficient catalytic pathway with the defa ligand leads to the para borylation while in the case of bpy the borylation at the para and meta sites compete. [ABSTRACT FROM AUTHOR]

Over the past two decades, the C–H bond activation and functionalization reaction has been known as a prevailing method for the construction of carbon–carbon and carbon–heteroatom bonds using various transition metal catalysts. In this context, the iridium-catalyzed C–H bond activation and borylation reaction is one of the most valued methods. However, the major challenge in these borylation reactions is how to control the proximal (ortho) and distal (meta and para) selectivity. Interestingly, while so many approaches are now available for the proximal ortho selective borylation of arenes, borylation at the distal meta and or para position of arenes remains still challenging. Only a few approaches have been reported so far in the literature employing iridium catalysis. In this feature article, we have demonstrated some of the recent discoveries from our laboratories for the proximal (ortho) and distal (meta and para) selective borylation reactions. Moreover, some of the recent catalyst engineering discoveries for the selective proximal ortho borylation reactions for a diverse class of substrates have also been discussed. The discussion part of several other pioneering reports is limited due to the lack of scope of this feature article. [ABSTRACT FROM AUTHOR]

We report a convenient method for the highly site-selective borylation of 8-arylquinoline. The reaction proceeds smoothly in the presence of a catalytic amount of [Ir(OMe)(cod)]2 and 2-phenylpyridine derived ligand using bis(pinacolato)diborane as the borylating agent. The reactions occur with high selectivity with many functional groups, providing a series of borylated 8-aryl quinolines with good to excellent yield and excellent selectivity. The borylated compounds formed in this method can be transformed into various important synthons by using known transformations. [ABSTRACT FROM AUTHOR]

A new concept for the meta‐selective borylation of aromatic amides is described. It has been demonstrated that while esters gave para borylations, amides lead to meta borylations. For achieving high meta selectivity, an L‐shaped bifunctional ligand has been employed and engages in an O⋅⋅⋅K noncovalent interaction with the oxygen atom of the moderately distorted amide carbonyl group. This interaction provides exceptional control for meta C−H activation/borylation. L‐Shaped: A new concept for the meta borylation of aromatic amides is described. It has been shown that while esters give para borylations, amides result in meta borylations. For achieving high meta selectivity, an L‐shaped ligand is used and engages in an O⋅⋅⋅K noncovalent interaction with the moderately distorted amide carbonyl group, providing exceptional control for meta C−H activation/borylation. [ABSTRACT FROM AUTHOR]

A new concept for the meta‐selective borylation of aromatic amides is described. It has been demonstrated that while esters gave para borylations, amides lead to meta borylations. For achieving high meta selectivity, an L‐shaped bifunctional ligand has been employed and engages in an O⋅⋅⋅K noncovalent interaction with the oxygen atom of the moderately distorted amide carbonyl group. This interaction provides exceptional control for meta C−H activation/borylation. [ABSTRACT FROM AUTHOR]

Remote C−H functionalization of heterocyclic biaryls will be of great importance in synthesis and medicinal chemistry. Through adjusting the geometric relationship of the directing atom and target C−H bonds, two new catalytic templates have been developed to enable the functionalization of the more hindered ortho‐C−H bonds of heterobiaryls bearing directing heteroatom at the meta‐ or para‐positions, affording unprecedented site‐selectivity. The use of template chaperone also overcomes product inhibition and renders the directing templates catalytic. The utility of this protocol was demonstrated by olefination of heterocyclic biaryls with various substituents, overriding conventional steric and electronic effects. These ortho‐C−H olefinated heterobiaryls are sterically hindered and can often be challenging to prepare through aryl‐aryl coupling reactions. [ABSTRACT FROM AUTHOR]

Remote C−H functionalization of heterocyclic biaryls will be of great importance in synthesis and medicinal chemistry. Through adjusting the geometric relationship of the directing atom and target C−H bonds, two new catalytic templates have been developed to enable the functionalization of the more hindered ortho‐C−H bonds of heterobiaryls bearing directing heteroatom at the meta‐ or para‐positions, affording unprecedented site‐selectivity. The use of template chaperone also overcomes product inhibition and renders the directing templates catalytic. The utility of this protocol was demonstrated by olefination of heterocyclic biaryls with various substituents, overriding conventional steric and electronic effects. These ortho‐C−H olefinated heterobiaryls are sterically hindered and can often be challenging to prepare through aryl‐aryl coupling reactions. [ABSTRACT FROM AUTHOR]

A method of para‐selective borylation of aromatic amides is described. The borylation proceeded via an unprecedented substrate–ligand distortion between the twisted aromatic amides and a newly designed ligand framework (defa) that is different from the traditionally used ligand (dtbpy) for the C−H borylation reactions. The designed ligand framework (defa) has led to the development of a new type of catalytic system that shows excellent para selectivity for a range of aromatic amides. Moreover, the designed ligand has shown excellent reactivity and selectivity for a range of heterocyclic aromatic amides. The identification of key transition states and intermediates using the DFT computations associated with the three regio‐isomeric pathways revealed that the most efficient catalytic pathway with the defa ligand leads to the para borylation while in the case of bpy the borylation at the para and meta sites compete. [ABSTRACT FROM AUTHOR]

The bearing is an essential component of a rotating machine. Sudden failure of the bearing may cause an unwanted breakdown of the manufacturing plant. In this paper, an intelligent fault diagnosis technique was developed to diagnose various faults that occur in a deep groove ball bearing. An experimental setup was designed and developed to generate faulty data in various conditions, such as inner race fault, outer race fault, and cage fault, along with the healthy condition. The time waveform of raw vibration data generated from the system was transformed into a frequency spectrum using the fast Fourier transform (FFT) method. These FFT signals were analyzed to detect the defective bearing. Another significant contribution of this paper is the application of a machine learning (ML) algorithm to diagnose bearing faults. The support vector machine (SVM) was used as the primary algorithm. As the efficiency of SVM heavily depends on hyperparameter tuning and optimum feature selection, the particle swarm optimization (PSO) technique was used to improve the model performance. The classification accuracy obtained using SVM with a traditional grid search cross-validation (CV) optimizer was 92%, whereas the improved accuracy using the PSO-based SVM was found to be 93.9%. The developed model was also compared with other traditional ML techniques such as k-nearest neighbor (KNN), decision tree (DT), and linear discriminant analysis (LDA). In every case, the proposed model outperformed the existing algorithms. [ABSTRACT FROM AUTHOR]

In this paper we present an improved zero-power controlled magnetic suspension system that has the capability to adjust stiffness. The conventional zero-power control system produces constant negative stiffness, and the stiffness solely depends on the capacity of the permanent magnets or the gap–force coefficient of the magnets. This becomes an obstacle to the fields of application of zero-power control where the adjustment of stiffness is necessary, such as developing a vibration isolation system. In this research, the basic zero-power control system is modified such that it can adjust stiffness by adding a minor proportional feedback of displacement to the zero-power controller. Finally, a vibration isolation system is developed by combining a positive stiffness spring in series with a negative stiffness suspension realized by the modified zero-power controller. The proposed control system and the developed vibration isolation system are investigated both analytically and experimentally. [ABSTRACT FROM PUBLISHER]

Abstract: This paper proposes a module-type three-degree-of-freedom vibration isolation system using modified zero-power control. Three vibration isolation modules are connected together using parallel mechanism to control 3-DOF motions. Each module consists of a common base, an individual middle mass and a common isolation table. The base to the middle mass is suspended by positive springs generated by active and passive system, and the middle mass and the isolation table is connected by negative spring realized by active-type modified zero-power control. The developed system could realize zero-compliance to direct disturbances as well as good ground vibration isolation. Furthermore, the isolation table is supported by a weight support mechanism for supporting heavy payloads. In the previous research, a concentrated middle mass with redundant actuators, in the vertical and horizontal directions, were used. Therefore, a vibration isolation system is proposed in this work using modular concept to overcome those drawbacks. Each module is controlled separately by decentralized control technique, and three modules can be used for three-degree-of-freedom of motion control. Therefore, no redundancy of actuator is occurred. Moreover, an improved zero-power controller is presented that can adjust negative stiffness instead of conventional zero-power controller. The results obtained from analytical and experimental studies show that the modular technique is reliable and efficient approach to vibration control, and represents a suitable alternative to the conventional active vibration isolation systems. [Copyright &y& Elsevier]

The aims of this paper are to develop hybrid energy systems considering biomass energy sources as well as a framework and optimal configuration of hybrid systems of energy for a southern sub-urban area of Bhola district in Bangladesh, named Kukri Mukri island, and analyse the feasibility of the techno-economic prospects of these systems. In this work, electrification for the rural area is analysed for different configurations of the hybrid systems. The estimation of available resources with optimal sizing and analysis of techno-economic aspects is done through HOMER Pro software to satisfy the demand of peak load. Different configurations of hybrid energy systems, including PV/diesel, PV/wind, PV/diesel/wind, PV/wind/diesel/biomass, and wind/diesel, are analysed and compared through optimization of different energy sources in HOMER. The size of the system and components are optimized and designed depending on the net present cost (NPC) and the levelized cost of energy (LCOE). Due to the lower availability and rising cost of wind energy, the outcome of this work shows a solar-based photovoltaic (PV) as the main energy source, battery as the storage media, and diesel generator as an energy source for backup. The results indicate that LCOE is much lower for PV/wind/diesel/biomass (0.142 USD/kWh) than PV/diesel (0.199 USD/kWh), PV/wind (0.239 USD/kWh), PV/diesel/wind (0.167 USD/kWh), PV/diesel (0.343 USD/kWh), and wind/diesel (0.175 USD/kWh). Additionally, it is demonstrated from the research that the genetic algorithm (GA) process gives sustainable and cost-effective outcomes compared to HOMER. [ABSTRACT FROM AUTHOR]

Energy demand is rising over time in both developing and developed countries. Therefore, finding new sources of energy is a prime concern now. For this effort, this paper presents the pyrolysis of onion (Allium cepa) shells in a reactor with a fixed bed for generating alternative liquid fuel. This paper also compares alternative fuel characteristics, including higher heating value, viscosity, density, pour point, and flash point, with conventional petroleum fuels at optimal process conditions. The work adopted pyrolysis to produce liquid fuel at a temperature range of 400–550 °C and utilized LPG to provide a heat source. The liquid product (fuel oil) was collected, and non-condensable gas was flared. The liquid product was tested for various properties, and the results of the analyses show that alternative fuel has a higher heating value of 12.227 MJ/kg, density of 800 kg/m3, viscosity of 4.3 cP at 30 °C, pour point below −6.2 °C, and flash point around 137 °C, with a variation due to the volatile matters. To obtain favorable conditions for pyrolysis, some parameters, including bed temperature, sample quantity, average particle size, and operating time, were varied and analyzed. The physio-chemical properties made the alternative fuels isolated from conventional petroleum fuels due to the variation in distillation temperature. This work shows that the fuel oil generated from the pyrolysis of onion shells could be considered an alternative source of fuel. [ABSTRACT FROM AUTHOR]

One of the biggest issues impeding a country's progress is the lack of power. To overcome this issue, hybrid renewable energy systems (HRES) play an important role. Due to rising consumption and diminishing resources globally, sustainability has recently attracted more attention. Bangladesh has access to renewable energy sources, including solar, micro-hydro, biomass, wind, and others. The objective of this research is to minimize the net present cost (NPC), cost of energy (COE), and CO2 emissions of the suggested electricity network using the Hybrid Optimization Model for Multiple Energy Resources (HOMER) Pro Software. This investigation explores the possible use of a hybridized energy system (i.e., solar, wind, and diesel) with battery storage in Bangladesh's northern area. Utilizing HOMER Pro software, an optimal grid-connected system is chosen after evaluating the techno-economic viability of several configuration options. For the Rangpur metropolitan region, seven distinct grid-connected solutions with stationary renewable sources are simulated. The HRES is designed to meet demands for hospital, diagnostic, school, and operation theatre loads of 3250.00 kWh, 250.00 kW maximum requirement, and 570.00 kWh, 71.25 kW maximum electricity demand, respectively. Multivariate linear regression (MLR) is used to assess the suggested optimal combination in terms of system size, cost, technical performance, and environmental stability. The findings show that the metric real-time rate (annual) has emerged as the most advantageous option since economic criteria like total NPC and COE are preferred above others. [ABSTRACT FROM AUTHOR]

Transition metal-catalysed direct borylation of hydrocarbons via C–H bond activation has received a remarkable level of attention as a popular reaction in the synthesis of organoboron compounds owing to their synthetic versatility. While controlling the site-selectivity was one of the most challenging issues in these C–H borylation reactions, enormous efforts of several research groups proved instrumental in dealing with selectivity issues that presently reached an impressive level for both proximal and distal C–H bond borylation reactions. For example, in the case of ortho C–H bond borylation reactions, innovative methodologies have been developed either by the modification of the directing groups attached with the substrates or by creating new catalytic systems via the design of new ligand frameworks. Whereas meta and para selective C–H borylations remained a formidable challenge, numerous innovative concepts have been developed within a very short period of time by the development of new catalytic systems with the employment of various noncovalent interactions. Moreover, significant advancements have occurred for aliphatic C(sp3)–H borylations as well as enantioselective borylations. In this review article, we aim to discuss and summarize the different approaches and findings related to the development of directed proximal ortho, distal meta/para, aliphatic (racemic and enantioselective) borylation reactions since 2014. Additionally, considering the C–H borylation reaction as one of the most important mainstream reactions, various applications of this C–H borylation reaction toward the synthesis of natural products, therapeutics, and applications in materials chemistry will be summarized in the last part of this review article. [ABSTRACT FROM AUTHOR]

This work reports on an extensive investigation of the physicochemical properties, engine performance, exhaust emissions, and fundamental energy and exergy parameters of waste‐plastic oils blended with an additive, diethyl ether and diesel. A four‐stroke single‐cylinder diesel engine was used for the engine experiments. The seven fuels in this study include a neat diesel, a neat waste plastic oil, two binary blends of diesel‐waste plastic oil, and three ternary blends of diesel with waste plastic oil and diethyl ether. The justification for selecting diethyl ether was to augment fuel properties in the blend and to further reduce emissions. The reasons for choosing waste plastic are not only to harness energy from waste plastic but also to offer an effective solution to the plastic waste management issue. The choice of diesel was to use it as a reference fuel for comparison with other fuels. Fuel properties were observed to be similar, and in some cases better, with the blends. Notable reductions in emissions with identical engine performance and energy and exergy parameters were observed with the five oxygenated blends (plastic oil blends) than with a reference diesel fuel. © 2021 Society of Chemical Industry and John Wiley & Sons, Ltd [ABSTRACT FROM AUTHOR]