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This article reviews the multidisciplinary aspects of MXene, including its structures, synthesis methods, and electronic, mechanical, optoelectronic, and magnetic properties.

Dye-sensitized solar cells (DSSCs) are one of the most versatile and low-cost solar cells. However, DSSCs are prone to low power conversion efficiency (PCE) compared to their counterparts, owing to their different synthesis parameters and process conditions. Therefore, designing efficient DSSCs and identifying the parameters that control the PCE of DSSCs are a critical tasks. We have collected data from hydrothermally synthesized DSSCs in the present work, published from 2005 to 2020. In line with publishing trends in the said period, we evaluate ZnO as a popular photoactive material for DSSC applications. We further analyzed the performance of hydrothermally synthesized ZnO DSSCs using different statistical techniques and provided some significant insights. We further applied the machine-learning technique with a decision tree algorithm to understand and discover the possible set of rules and heuristics that govern the morphology of the hydrothermally grown ZnO. In addition, we also employed supervised and unsupervised machine-learning models using conventional decision trees and classification and regression trees, respectively, to identify the dependence of the PCE of ZnO DSSCs on the different synthesis parameters. The reported work also evidences the PCE predictions of the ZnO DSSCs by using random forest and artificial neural network algorithms. The results substantiate that the random forest and artificial neural network algorithms successfully predict the PCE of the ZnO DSSCs with reasonable accuracy. Thus, we present a novel approach of applying statistical analysis and machine-learning algorithms to understand, discover, and predict the performance of DSSCs. We recommend extending the said know-how to other solar cells to identify rules and heuristics and experimentally realize highly efficient solar cells in shrinking manufacturing windows with a cost-effective approach.

In recent years, resistive switching memory devices are attracted much attention for high-density non-volatile memory applications owing to their cell scalability, multilevel operations, and 3D capability in crossbar memory arrays. In this work, we report the forming-free and multilevel resistive switching properties of hydrothermally synthesized hexagonal molybdenum oxide (h-MoO3) microrods. The formation of h-MoO3 microrods was confirmed by using the X-ray diffraction technique and scanning electron microscopy. Different chemical properties of h-MoO3 microrods were determined by energy-dispersive X-ray, photoluminescence, Raman, and X-ray photoelectron spectroscopic techniques. The memory device was fabricated in a Ti/MoO3/FTO structure and its bipolar resistive switching properties were investigated. The memory device shows voltage-dependent tunable I-V properties and shows electroforming-free operation. Moreover, we have calculated the different memristive properties and showed that the device possesses double-valued charge-magnetic flux characteristics, suggesting the dominance of memristive properties in the Ti/MoO3/FTO device. We further explored the multilevel resistive switching property of the device by varying the RESET voltage. The Ti/MoO3/FTO memristive device can able to show four distinct resistive states during endurance and retention tests. The statistical analysis suggested that the device has less variation during the cycle-to-cycle operation. The device conduction mechanism was obtained by fitting different charge transport models, and a possible resistive switching mechanism is presented based on the observed multilevel resistive switching effect of the Ti/MoO3/FTO memristive device.

This paper presents an organic memristive device based on the soft and quasi-liquid trypsin biomaterial. Accordingly, trypsin is isolated from the bovine pancreas and deposited on a conducting fluorine-doped tin oxide (FTO) substrate. The current–voltage (I–V) measurements of the trypsin/FTO device show a hysteresis loop at multiple frequencies and voltages. The results demonstrate that the current and resistance of the device can be modulated by altering the frequency and magnitude of the applied signal, suggesting the feasibility of this material for brain-inspired computing devices. The hysteresis area of the device increases in proportion to the frequency of the signal, signifying the inverse-memristive phenomenon. The time-domain flux, time-domain charge, and charge-flux properties are calculated from the experimental I–V data to demonstrate the memristive nature of the trypsin hydrogel. Interestingly, the trypsin hydrogel memristive device mimics bio-synaptic properties such as potentiation–depression and four complex spike-time-dependent plasticity learning rules. Electrochemical studies are performed to understand the electrochemical kinetics of the device. A possible switching mechanism is illustrated to show the memristive effect of the trypsin hydrogel. The results of the present investigation suggest that trypsin can be a possible biomaterial to develop an electronic synaptic device for neuromorphic computing applications.

The term “fourth industrial revolution” is used as a framework for analyzing the influence of coming technologies on the full range of societal impact on the current generation, evolving cultural laws, governmental view, economical growth, and foreign affairs. The fourth industrial revolution idea confirms that technological change is the engine of change in relevant sectors and elements of society. It underscores the theme that many technologies have emerged at some point in history that has been combined in ways that have had an impact on incremental efficiency gains. This chapter introduces how this new revolution has brought great opportunities; the core potential of this industrial revolution is to increase manufacturing output globally to meet social needs and to enhance the capacity across all the different current systems. The chapter focuses on various novel techniques that sustain this ultra-modern era and delineates the influence, prospects, desires, and acclimation of Industry 4.0 from the social viewpoint.

The fourth technological revolution, which is widely called Industry 4.0, works by incorporating the critical features like physical (object in existence), digital, and biological worlds. The attributes related to Industry 4.0 are more important as they change from producing a large amount of standardized products by using manual assembly, semi-automated assembly, or fully automated assembly with customization based on different product manufacturing. The fourth technological revolution is not progressing to modification; however, “it can modify us” and revolutionize societal life. The chapter elucidates the essential technologies behind Industry 4.0 and how they are shaping smart manufacturing and digital supply chain management. It also throws light on the policy frameworks required to be adopted to inculcate Industry 4.0 in the walks of societal life and reviews the upcoming trends.

The massively parallel computing capabilities of the human brain can be mimicked with the help of neuromorphic computing approach and this can be achieved by developing the electronic synaptic device. In the present work, we have synthesized gallium-doped ZnO thin films using a cost-effective hydrothermal method and characterized the thin films using field-emission scanning electron microscopy and energy-dispersive X-ray spectroscopy. Furthermore, gallium-doped ZnO memristive devices were developed using standard procedure and electrically characterized for the neuromorphic application. In particular, resistive switching and synaptic properties of gallium-doped ZnO thin films were investigated. The bipolar resistive switching with an analog memory like behavior was observed in the developed memristive devices. In the present case, good synaptic properties, endurance, and retention characteristics were observed for 0.5% Ga doped memristive device. Our results suggested that the synaptic weight, potentiation-depression, and symmetric Hebbian learning can be tuned with properly engineering the ZnO memristive device with appropriate gallium doping. The detailed analysis of I-V results suggested that resistive switching is occurred due to Ohmic and Schottky conduction mechanisms. Keywords: Memristive device, Resistive switching, Gallium doped ZnO, Electronic synapse, Potentiation and depression, Hebbian learning

Preparing question paper set for any examination is one of the most challenging jobs. Such task is assigned to the paper setter. Paper setter requires more time and efforts to prepare a paper scientifically. To minimize the effort of paper setter and to improve the transparency of question paper, automation takes place. Automation of this process will improve the effectiveness and lessen human errors. It will eliminate manual work of browsing question bank for each test. It will require one-time effort just to generate question bank. Once the question bank is ready, any number of question papers will be generated according to the requirement. This application can be used to generate question papers for several subjects of several classes. It can generate question paper on demand within few seconds. We can save these created question papers. Paper setter can set the criteria for question paper and can create paper accordingly.

Blockchain, a buzz word in the second decade of the current century, is a decentralized technology enabling facilitation of distributed ledger with immutable transactions, updated time-to-time at every node. The beauty is such an absence of centralized authority, transactions, or digital assets that can be shared across a P2P network. This technology was conceived way back in the 90s by a group of researchers. Though the primary aim was for time-stamping documents, after two decades, in 2009, the first blockchain, i.e., bitcoin came into the market and soon became the talk of the time. Other popular cryptocurrencies in blockchain such as Ethereum, Litecoin, Ripple, and Stellar also emerged in the form of intangible currencies working on the very principle of cryptography. These days, Ethereum has become more popular since it is featured prominently for “smart contracts” for decentralized and self-executing agreements. There are so many advantages of blockchain over the traditional system. Blockchain is enriched by its dominating characteristics such as decentralized, distributed, secure and faster, transparent, immutable and insusceptible to tampering. Every node in blockchain can propose new transactions, to validate this transaction consensus mechanism play a crucial role in a structured way, i.e., proof of work and the proof of stake mechanism. Thus in a nutshell blockchain is a cutting-edge technology that proves it is time-saving, cost-saving, and rigid security. It is also advantageous over inefficient, expensive, and vulnerable transactions. It creates resistance against fraud, cybersecurity attacks without involving centralized authority. Moreover, it is secure with a cryptographic shield that contains a hash function, public-key cryptography, and digital signatures, and so on. Though phenomenal growth of blockchain in various applications like cybersecurity, supply chain, online data storage, networking, IoT, insurance, government, multimedia, and real estate is witnessed, few domains remain untouched by developers and tech savvies. The sole aim of this chapter is to focus on such untouched domains, besides showcasing the evolution of this novel platform. This chapter aims to cover the basic essence of blockchain with basic architecture and working principles. The societal applications will be dealt with in-depth. The chapter will present a lucid flow of the blockchain technology details with the potential for further exploration.

Removable drive requires less user interface to install on a system than other types of hardwaredevices. They have become the most common means of storing data. They can store large amount of informationas well as malwares. Removable drive has turn out to be a new transporter in spreading computer viruses.Whenever a malicious removable drive containing malwares is attached to computer, it can corrupt data or thewhole system. With the necessity to protect system from removable drives containing malwares, Removable DriveBlocker came into existence. It will detect virus with the help of antivirus software present on the screen and willblock the device immediately

E-learning lends a significant contribution to the education system. Learner’s interests, skills, domain knowledge, learning behavior, and learning styles are essential for developing a personalized e-learning system. Student centric learning process improves learners’ satisfaction, leading to improving the education system’s outcome. Due to the advancement of ICT technologies variety of e-study material is available through various online sources. It is a challenge for today’s e-learners to select the best e-learning material which fulfills their learning needs. This paper explores an intelligent, personalized learning approach to assess learner’s domain knowledge. The result of the said assessment helps to recommend a learning path for the learner.

In the present investigation, we have experimentally demonstrated the coexistence of filamentary and homogeneous resistive switching mechanisms in single Al/MnO2/SS thin film metal–insulator–metal device. The voltage-induced resistive switching leads to clockwise and counter-clockwise resistive switching effects. The present investigations confirm that the coexistence of both RS mechanisms is dependent on input voltage, charge-flux and time. Furthermore, the non-zero I–V crossing locations and crossovers hysteresis loops suggested that the developed device has memristive and meminductive properties. The memristive and meminductive memory effects are further confirmed by electrochemical impedance spectroscopy. The results suggested that the mem-device dynamics and electrochemical kinetics during different voltage sweeps and sweep rates are responsible for the coexistence of filamentary and homogeneous resistive switching mechanisms as well as memristive and meminductive memory effect in single Al/MnO2/SS metal–insulator–metal device. The coexistence of both RS effects is useful for the development of high-performance resistive memory and electronic synapse devices. Furthermore, the coexistence of memristive and meminductive memory effects is important for the development of adaptive and self-resonating devices and circuits. Published version

In the present work, the hydrothermal approach is employed to develop 1D-TiO2 nanorod array memristive devices and the effect of hydrothermal growth temperature on TiO2 memristive devices is studied. X-ray diffraction (XRD) analysis suggested that the rutile phase is dominant in the developed TiO2 nanorod array. Field emission scanning electron microscopy (FESEM) images show well adherent and pinhole free one dimensional (1D) TiO2 nanorods. The presence of titanium and oxygen in all the samples was confirmed by energy dispersive X-ray spectroscopy (EDS). Furthermore, growth of the 1D TiO2 nanorods depends on the growth temperature and uniform growth is observed at the higher growth temperatures. The well-known memristive hysteresis loop is observed in the TiO2 nanorod thin films. Furthermore, resistive switching voltages, the shape of I-V loops and (non)rectifying behavior changed as the growth temperature varied from 140 °C to 170 °C. The biological synapse properties such as paired-pulse facilitation and short-term depression are observed in some devices. The detailed electrical characterizations suggested that the developed devices show doubled valued charge-magnetic flux characteristic and charge transportation is due to the Ohmic and space charge limited current. Keywords: Memristive device, TiO2, Nanorods, Hydrothermal method, Resistive switching, Neuromorphic computing

In this study, the in situ sol–gel method has been deployed to prepare the titanium dioxide/multiwalled carbon nanotubes (TiO2/MWCNTs) nanocomposite (NCs) powders with varying content of MWCNTs (0.01–1.0 wt %), to construct the dye-sensitized solar cells (DSSCs). First, binder-free NCs were deposited on a transparent-conducting F:SnO2 (FTO) glass substrate by a doctor-blade technique and then anchored with Ru(II)-based dyes to either N719 or ruthenium phthalocyanine (RuPc). The structural and optical properties and interconnectivity of the materials within the composite are investigated thoroughly by various spectral techniques (XRD, XPS, Raman, FT-IR, and UV–vis), electron microscopy (HRTEM), and BET analysis. The experimental results suggest that the ratio of MWCNTs and TiO2 in NCs, morphology, and their interconnectivity influenced their structural, optical, and photovoltaic properties significantly. Finally, the photovoltaic performances of the assembled DSSCs with different content of MWCNTs to TiO2 films anchored with two different dyes were tested under one sun irradiation (100 mW/cm2). The measured current–voltage (IV) curve and incident photon-to-current conversion efficiency (IPCE) spectra of TiO2/0.1 wt % MWCNTs (T@0.1 C) for N719 dye show three times more power conversion efficiency (η = 6.21%) which is opposed to an efficiency (η = 2.07%) of T@0.1 C for RuPc dye under the same operating conditions.