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Hydrogen Evolution Reaction by Platinum Coating
No full textA thin layer of platinum coating (0.5 µgcm−2) on stainless steel surface was deposited by direct current (DC) and pulse current (PC) electrodeposition method for hydrogen evolution reaction (HER) application. Scanning electron microscopy, atomic force microscopy, and X-ray diffraction analysis were used to characterize the coatings. Linear sweep voltammetry and cyclic voltammetry studies were carried out to know the overpotential values for hydrogen evolution reaction (HER) on these coatings. The optimization of catalytic activity for hydrogen evolution using different coating methods helps in reducing the overall cost. Tafel polarization experiments were conducted for DC and PC platinum coating to know hydrogen generation trend. Cathodic slope and HER current values revealed that, coatings obtained at 75% duty cycle by PC method exhibit lower cathodic slope, high current density of 150 mA/cm2 and more corrosion current with highest hydrogen evolution. Chronopotentiometry experiments showed that 20 ml of hydrogen was collected from 75% sample
Memory effect of vertically stacked hBN/QDs/hBN structures based on quantum-dot monolayers sandwiched between hexagonal boron nitride layer
No full textThe characteristics of a flexible write-once-read-many-times (WORM) memory fabricated with monolayered 0-dimensional (0D) CdSe–ZnS quantum dots (QDs) layers sandwiched between two insulating 2-dimensional (2D) hexagonal boron nitride (hBN) multilayers were investigated by electrical measurement method. The hBN/QDs monolayer/hBN structure was fabricated in a vertical stacked structure using a technique which control the formation of the QDs monolayer. QDs monolayer was formed by electrostatic interaction between the negative charge group on the CdSe–ZnS QDs surface and the positive charge group on the hBN surface. The device has a WORM characteristic due to the presence of QDs in the current-voltage (I–V) measurement. When a bias is applied, carriers were initially trapped by tunneling due to the QDs and then a conductive filament was formed in the hBN, which were not detrapped and exhibit characteristics of write-once-read-many-times memory. The maximum ON/OFF ratio of the current for the devices was as large as 4 × 10, and the endurance was 5 × 104 cycles, and a retention time was larger than 1 × 105 s. In order to explain the carrier transport mechanism and conductive filament of the WORM memory device caused by QDs, it through various methods such as I–V fitting data, simulation, and conductive AFM. Unlike the conventional conductive filament mechanism, through random diffusion such as Ag filament, the Au/hBN/QD/hBN/ITO/PET structures implemented a consistent conductive filament using Au metal and QDs active layer
Temperature effect on molecular rotational dynamics of NMBHC-2-one in ethanol and octanol solvents
No full textRotational reorientation dynamics of NMBHC-2-One has been studied in ethanol and octanol solvents by varying temperature using picosecond time-resolved spectroscopy. Experimental rotational reorientation time shows NMBHC-2-One experiences higher friction in octanol than ethanol. Qualitative analysis using SED, GW, and DKS mechanical frictions theories has been performed. The theoretical measured reorientation times of NMBHC-2-One fails to explain the observed experimental values, it enables us to test dielectric friction theories. © 2021 Author(s)
Correlates of sperm quality parameters and oxidative stress indices in diabetic rats exposed to cold stress: Role of moringa oleifera leaf extract
No full textSpermatogenesis is extremely sensitive to fluctuations in the environment, particularly temperature and hormones. Sperm dysfunction, a root cause of male infertility, is a commonly allied complication of diabetes mellitus. Our previous studies cogitate that cold stress (15°C) exacerbates the complications and the resultant oxidative stress plays a major role in testicular and epididymis dysfunction in diabetic rats. Despite the strong biologic prospect for this postulation, establishing a direct link between free radicals and specific disease is an in-dire need, and in this context, this study focuses on investigating the sperm quality parameters and their relationship to testicular oxidative stress indices of cold stress diabetes in Wistar rats. The results indicate a cumulative impact by diminishing sperm parameters, viz. sperm density, viability, motility, mortality, and acrosome intactness in cold-stressed diabetic rats. The findings also reveal a strong positive Pearson’s correlation between the sperm quality parameters and testicular lipid peroxidation, which reflects the influence of oxidative stress on sperm dysfunction. Together with duel stressor effects, the efficacy of Moringa oleifera leaf ethanolic (MOLE) extract is appended to assess its therapeutic role. The apparent effectiveness of MOLE therapy at 250 and 500 mg/kg bw for 60 days aided in suppressing oxidative stress and improved semen quality demonstrating the causative nature of these associations; hence, Moringa usage is recommended as a therapeutic agent for male reproductive dysfunctions in population residing in colder climates. © 2021 Basha, et al. This is an open access article distributed under the terms of the Creative Commons Attribution License-NonCommercial-ShareAlike Unported License (http://creativecommons.org/licenses/by-nc-sa/3.0/)
Effect of Donor and Acceptor on Optoelectronic Properties of Benzo[1,2-B:4,5-B′]dithiophene
Full text linkA series of acceptor and donor groups anchored to benzo[1,2-b:4,5-b′]dithiophene (BDT) molecule have been systematically investigated at the density functional theory (DFT) and time-dependent density functional theory (TDDFT) level to reveal structure–property relationships, charge transfer, and fluorescence lifetimes. The DFT optimization shows that the hetero atom in the ring induces the polarity from central ring to both ends of the thiophene ring, participating in the conjugation. The donor and acceptor groups were anchored at the terminals of the BDT at two different positions to fine-tune the properties according to the requirement and study the push–pull effect. All the models studied in this work retain their aromaticity as estimated from NICS(0) and NICS(1) aromaticity index in ground and excited states. The results show that the hardness, softness, HOMO–LUMO gaps, ionization potentials (IP), and electron affinities (EA) of the BDTs are significantly affected by the electron-withdrawing and electron-donating groups. The 1H and 13C NMR chemical shift values have been computed to quantify the push–pull effect. Further, the charge transfer properties in these BDTs were explored based on reorganization energies and diagnostic descriptors derived from hole–electron theory that present different electron excitation behavior. The relationship between the computed variables such as highest occupied molecular orbital, lowest unoccupied molecular orbital, oscillator strength, dipole moment, absorption, and fluorescence energy correlates the system with one another and also to extend the possible applications of the system in optical devices. Structure–property relationship of various BDTs reveal that, upon optical excitation, the resonance effect plays an important role changing the bonding character between the substituent and BDT unit, enabling efficient electron delocalization. The examination of TDDFT results indicates that among the various models studied in this work, nitro-substituted model is better candidate for optoelectronic properties with relatively large absorption wavelength and long fluorescence lifetime
Optimization study for enhanced production of hyaluronic acid from Streptococcus equisimilus MK156140
Full text linkHyaluronic acid finds its complete application in areas such as therapeutics, cosmetics, and as a health supplement. In the present investigation, standardization for the production of hyaluronic acid by Streptococcus equisimilus MK156140 in complex media was performed. Some of the selected physicochemical parameters such as pH, temperature, speed, incubation time, sucrose, yeast extract, and beef extract were screened using Plackett-Burman foldover design. Further, the screened parameters interaction was investigated using central composite design (CCD) and closely compared with OVAT studies. At a pH of 7.38, with beef extract, 12.15%, and yeast extract 7.64%, the observed yield was 7.16 g/L, which was in close line with the predicted value of 7.21 g/L
Organic Reactions Using Clay and Clay‑Supported Catalysts: A Survey of Recent Literature
Full text linkClays and modifed or supported clays have become some of the widely used catalysts for a variety of organic reactions,
due to their easy structural modifcations and activation, low-cost, eco-friendly nature, ready availability, ability to act as
acidic or basic catalyst without being corrosive. The present review is a survey of the literature dealing with most of the
important work on clay catalysed organic reactions published during the period 2011–2020, and is a sequel to our previous
review covering the literature of 2001–2010. The review consists of various segments starting with introduction that briefy
mentions the structure and modifcation of clay minerals, particularly the most widely used montmorillonite, followed by
organic reactions such as condensation, addition, substitution, elimination, reduction, oxidation, wastewater remediation,
biodiesel synthesis and a few miscellaneous reactions that are accomplished using these catalysts. Among these, biodiesel
synthesis and remediation are widely investigated transformations, and fnd practical applications
Energy Concerned Clustering Mechanism to Ensure Reliable Data Transmission in Wireless Sensor Network
No full textIn wireless sensor networks, data reception capability along with higher QoS can be achieved by adapting clustering mechanisms in the network. Hierarchical networks increase data aggregation efficiently. The hierarchical network includes optimal cluster creation and cluster head (CH) selection that yield higher QoS in the network. Hybrid particle swarm optimization with firefly algorithm (HPSOFA) is proposed for CH selection to obtain optimal clustering in the network. Transmission overhead is reduced by 9% when compared with the existing method by applying a modified dynamic source routing (DSR) algorithm. The proposed algorithm addresses the adaptive congestion window size adjustment method to avoid congestion occurrences in the network. Thus, the proposed HPSOFA method improves QoS and establishes reliable communication in the network
VEDSDA: Voronoi Encryption and Decryption for Secure Data Aggregation in WSNs
Full text linkThe various application in Wireless Sensor Networks fascinated towards minimal and secure data transmission. In this paper, VEDSDA protocol is proposed to achieve reduction of data redundancy, data length and providing security for data transmission. The VEDSDA protocol used compression technique to reduce data length which helps to utilize less energy consumption. The data compression technique involves leveling, encoding and decoding phases. Levelling phase converts data to logical data where as encoding phase compress the data size at the source node and decoding phase decompress the data size at the destination. The voronoi diagram concept is used to encrypt and decrypt aggregated data. Thus, VEDSDA protocol is compared with existing protocol and proves better enhancement
Real World Face Mask Detection using MobileNetV2 and Raspberry Pi
Full text linkOn March 12, 2020, Corona Virus Disease 2019 (COVID 19) was declared a global pandemic. Because of its quick spread from one person to another, this disease was thought to be more hazardous. Face masks have proven to be a good and effective way to stop the spread of COVID 19. Detection of Face Mask is a challenging problem. This paper proposes the method to solve this challenge by using deep learning. This work uses Multi-Task Cascaded Convolutional Neural Network (MTCNN) for detection and identification of face. MobileNetV2 is used as an object detector for mask detection. A total of 3833 images from different data sources were chosen for this work. This is later implemented using Raspberry Pi and pi cam, this setup transmits live video data from a remote location and hence the prediction of wearing mask is accomplished. The amount of information lost in the process is decreased gradually at 20th epoch is 0.0199. The accuracy by which the mask/no mask detection is increased