Showing papers by "Motilal Nehru National Institute of Technology Allahabad published in 2021"

Recent trends in laser cladding and surface alloying

Abstract: Laser cladding and surface alloying are surface modification techniques employed to fabricate thin coating/layer with improved surface properties or to refurbish surface defects by forming highly resistant gradient coatings/layers on the substrate. High energy density and cooling rates make these techniques suitable to process a wide range of materials. In recent years, due to the development of high power lasers, improved controlling and delivery mechanisms have attracted extensive research in laser surface treatment. Researchers have analyzed various process factors to improve process performance. The experimental and theoretical studies show that the performance of laser cladding and surface alloying techniques can be enhanced significantly by the proper selection of input process parameters. This paper summarizes various research works carried out so far in the area of laser cladding and surface alloying of different materials and their applications. It reports the research outcomes of experimental and theoretical studies conducted to improve the process performance. A brief introduction of various laser surface treatment processes is also included. Besides these various problems, their solutions and trend for future works have also been discussed.

Groundwater quality assessment using water quality index (WQI) under GIS framework

Abstract: Groundwater is an important source for drinking water supply in hard rock terrain of Bundelkhand massif particularly in District Mahoba, Uttar Pradesh, India. An attempt has been made in this work to understand the suitability of groundwater for human consumption. The parameters like pH, electrical conductivity, total dissolved solids, alkalinity, total hardness, calcium, magnesium, sodium, potassium, bicarbonate, sulfate, chloride, fluoride, nitrate, copper, manganese, silver, zinc, iron and nickel were analysed to estimate the groundwater quality. The water quality index (WQI) has been applied to categorize the water quality viz: excellent, good, poor, etc. which is quite useful to infer the quality of water to the people and policy makers in the concerned area. The WQI in the study area ranges from 4.75 to 115.93. The overall WQI in the study area indicates that the groundwater is safe and potable except few localized pockets in Charkhari and Jaitpur Blocks. The Hill-Piper Trilinear diagram reveals that the groundwater of the study area falls under Na+-Cl−, mixed Ca2+-Mg2+-Cl− and Ca2+- $${\text{HCO}}_{3}^{ - }$$ types. The granite-gneiss contains orthoclase feldspar and biotite minerals which after weathering yields bicarbonate and chloride rich groundwater. The correlation matrix has been created and analysed to observe their significant impetus on the assessment of groundwater quality. The current study suggests that the groundwater of the area under deteriorated water quality needs treatment before consumption and also to be protected from the perils of geogenic/anthropogenic contamination.

Selenium in soil-microbe-plant systems: Sources, distribution, toxicity, tolerance, and detoxification

Abstract: Selenium is an essential micronutrient required for natural biological systems such as anti-oxidative systems. Despite such beneficial aspect, contamination of selenium and its subsequent bioaccumu...

Green Synthesis of Gold Nanoparticles Using Plant Extracts as Beneficial Prospect for Cancer Theranostics.

Abstract: Gold nanoparticles (AuNPs) have been widely explored and are well-known for their medical applications. Chemical and physical synthesis methods are a way to make AuNPs. In any case, the hunt for other more ecologically friendly and cost-effective large-scale technologies, such as environmentally friendly biological processes known as green synthesis, has been gaining interest by worldwide researchers. The international focus on green nanotechnology research has resulted in various nanomaterials being used in environmentally and physiologically acceptable applications. Several advantages over conventional physical and chemical synthesis (simple, one-step approach to synthesize, cost-effectiveness, energy efficiency, and biocompatibility) have drawn scientists’ attention to exploring the green synthesis of AuNPs by exploiting plants’ secondary metabolites. Biogenic approaches, mainly the plant-based synthesis of metal nanoparticles, have been chosen as the ideal strategy due to their environmental and in vivo safety, as well as their ease of synthesis. In this review, we reviewed the use of green synthesized AuNPs in the treatment of cancer by utilizing phytochemicals found in plant extracts. This article reviews plant-based methods for producing AuNPs, characterization methods of synthesized AuNPs, and discusses their physiochemical properties. This study also discusses recent breakthroughs and achievements in using green synthesized AuNPs in cancer treatment and different mechanisms of action, such as reactive oxygen species (ROS), mediated mitochondrial dysfunction and caspase activation, leading to apoptosis, etc., for their anticancer and cytotoxic effects. Understanding the mechanisms underlying AuNPs therapeutic efficacy will aid in developing personalized medicines and treatments for cancer as a potential cancer therapeutic strategy.

A Secured and Robust Medical Image Watermarking Approach for Protecting Integrity of Medical Images

Abstract: In this paper, a novel medical image watermarking (MIW) technique for tele ‐ medicine applications is proposed. In this approach homomorphic transform (HT), redundant discrete wavelet tran...

Sensitivity Enhancement of MXene Based SPR Sensor Using Silicon: Theoretical Analysis

Abstract: In this seminal, we proposed a silicon and two-dimensional MXene (Ti3C2Tx) layer-based surface plasmon resonance (SPR) biosensor. Use of MXene layer facilitates the adsorption of biomolecules due to its larger surface area, stronger light matter interaction and higher binding energies. Silver, silicon thicknesses and the number of MXene layers of proposed SPR have been optimized for the best performance. Sensitivity, detection accuracy, and figure of merit acquired with 50 nm silver, 5 nm silicon film and for monolayer MXene at 633 nm wavelength is 231οRIU−1 0.17 Degree−1 and 39.83 RIU−1. Silicon layer is used between silver and MXene to increase the sensitivity. Proposed SPR sensor with silicon shows sensitivity enhancement of 99.83% and 95.68% over conventional SPR and proposed SPR without silicon respectively. However, highest sensitivity is reached to 349.9οRIU−1 for 50 nm silver and 7 nm silicon without any MXene layer.

Silicon induces adventitious root formation in rice under arsenate stress with involvement of nitric oxide and indole-3-acetic acid.

Abstract: Arsenic (As) negatively affects plant development. This study evaluates how the application of silicon (Si) can favor the formation of adventitious roots in rice under arsenate stress (AsV) as a mechanism to mitigate its negative effects. The simultaneous application of AsV and Si up-regulated the expression of genes involved in nitric oxide (NO) metabolism, cell cycle progression, auxin (IAA, indole-3-acetic acid) biosynthesis and transport, and Si uptake which accompanied adventitious root formation. Furthermore, Si triggered the expression and activity of enzymes involved in ascorbate recycling. Treatment with L-NAME (NG-nitro L-arginine methyl ester), an inhibitor of NO generation, significantly suppressed adventitious root formation, even in the presence of Si; however, supplying NO in the growth media rescued its effects. Our data suggest that both NO and IAA are essential for Si-mediated adventitious root formation under AsV stress. Interestingly, TIBA (2,3,5-triiodobenzoic acid), a polar auxin transport inhibitor, suppressed adventitious root formation even in the presence of Si and SNP (sodium nitroprusside, an NO donor), suggesting that Si is involved in a mechanism whereby a cellular signal is triggered and that first requires NO formation, followed by IAA biosynthesis.

Effects of COVID-19 lockdown phases in India: an atmospheric perspective.

Abstract: Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus. It was first identified in December 2019 in Wuhan, Hubei, China, and has resulted in an ongoing pandemic. As of 5 July 2020, more than 11.1 million cases have been reported across 188 countries and territories, resulting in more than 528,000 deaths. More than 6.03 million people have recovered. The entire world population currently faces enormous challenges (i.e., social, environmental, health, and economic) due to the impact of COVID-19. In this regard, the affected countries are now trying to slow down the virus’s transmission through social-distancing, lockdowns, increasing the number of tests and treatment facilities. There have been four lockdowns (25 March 2020–31 May 2020), and two unlock periods (1 June–31 July 2020) in India. Aerosol Optical Depth (AOD) has been analyzed using MODIS satellite data during various phases of lockdowns over India. With the implementation of lockdown steps, AOD values dropped significantly over various regions. A significant reduction in AOD over the North-Central regions (up to −50%) compared to the regions in the South or Northeast India. The AOD over these regions was significantly affected by the lock/unlock phases. It was also observed that there was a considerable buildup of AOD during the pre-lockdown period in the year 2020 as compared to the past two years.

Nitric oxide (NO) and salicylic acid (SA): A framework for their relationship in plant development under abiotic stress

Abstract: The free radical nitric oxide (NO) and the phenolic phytohormone salicylic acid (SA) are signal molecules which exert key functions at biochemical and physiological levels. Abiotic stresses, especially in early plant development, impose the biggest threats to agricultural systems and crop yield. These stresses impair plant growth and subsequently cause a reduction in root development, affecting nutrient uptake and crop productivity. The molecules NO and SA have been identified as robust tools for efficiently mitigating the negative effects of abiotic stress in plants. SA is engaged in an array of tasks under adverse environmental situations. The function of NO depends on its cellular concentration; at a low level, it acts as a signal molecule, while at a high level, it triggers nitro-oxidative stress. The crosstalk between NO and SA involving different signalling molecules and regulatory factors modulate plant function during stressful situations. Crosstalk between these two signalling molecules induces plant tolerance to abiotic stress and needs further investigation. This review aims to highlight signalling aspects of NO and SA in higher plants and critically discusses the roles of these two molecules in alleviating abiotic stress.

Analysis and Dynamics of Fractional Order Covid-19 Model with Memory Effect

Abstract: The present article attempts to examine fractional order Covid-19 model by employing an efficient and powerful analytical scheme termed as q-homotopy analysis Sumudu transform method (q-HASTM). The q-HASTM is the hybrid scheme based on q-HAM and Sumudu transform technique. Liouville-Caputo approach of the fractional operator has been employed. The proposed modelis also examined numerically via generalized Adams-Bashforth-Moulton method. We determined model equilibria and also give their stability analysis by employing next generation matrix and fractional Routh-Hurwitz stability criterion.

Two Port Circularly Polarized MIMO Antenna Design and Investigation for 5G Communication Systems

Abstract: A compact size wideband circularly polarized (CP) 2-port multiple-input-multiple-output (MIMO) antenna is designed for the fifth generation (5G) region under the sub-6 GHz band The presented antenna has (≤ − 10 dB) impedance bandwidth of 900 MHz (33–42 GHz) and has 100% 3-dB axial ratio bandwidth The antenna covers the potential 5G band ranging from 33 to 38 GHz having left-handed circular polarization characteristics To validate performance attributes of the MIMO antenna designed various diversity parameters such as envelope correlation coefficient (ECC), total active reflection coefficient, and diversity gain are calculated The low envelope correlation coefficient (ECC < 010) and the isolation between the antenna elements greater than 15 dB justify the acceptance of the proposed design as a MIMO antenna The proposed design exhibits good agreement between the simulated and the measured results

A New Mask R-CNN-Based Method for Improved Landslide Detection

Abstract: This article presents a novel method of landslide detection by exploiting the Mask R-CNN capability of identifying an object layout by using a pixel-based segmentation, along with transfer learning used to train the proposed model. A data set of 160 elements is created containing landslide and nonlandslide images. The proposed method consists of three steps: augmenting training image samples to increase the volume of the training data; fine-tuning with limited image samples; and performance evaluation of the algorithm in terms of precision, recall, and F1 measure, on the considered landslide images, by adopting ResNet-50 and 101 as backbone models. The experimental results are quite encouraging as the proposed method achieves precision equals to 1.00, recall 0.93, and F1 measure 0.97, when ResNet-101 is used as backbone model, and with a low number of landslide photographs used as training samples. The proposed algorithm can be potentially useful for land-use planners and policymakers of hilly areas where intermittent slope deformations necessitate landslide detection as a prerequisite before planning.

Spatiotemporal mapping of Land Use/Land Cover dynamics using Remote Sensing and GIS approach: a case study of Prayagraj City, India (1988–2018)

Abstract: Prayagraj City is one the biggest cities in the State of Uttar Pradesh which has been selected as Smart City by Ministry of Housing and Urban Affairs, Government of India, in 2015. This city has rapidly evolved in the last three decades due to the urbanization process. This study has used multispectral imageries of Landsat Thematic Mapper and Operational Land Imager/Thermal Infrared Sensor of four different time points at the interval of ~ 10 years, i.e., 1988, 1997, 2008, and 2018. These images have been preprocessed and then classified through supervised classification using Maximum Likelihood Classifier in ERDAS IMAGINE version 2014. The overall accuracy achieved is more than 88% in all the four time points. The periodical change results have revealed that all land use/land cover (LU/LC) classes has altered in all periods, i.e., 1988–1997, 1997–2008, 2008–2018, and 1988–2018 with remarkable trends, patterns, and magnitudes. The growth of Built-up land is a major concern. The results of the change matrix (1988–2018) have indicated that the most expanded class was built-up land which has evolved into 64.52% at the cost of Agriculture land by 24.41%, Forest land by 10.56%, and Barren land by 6.01%. The above results of LU/LC dynamics can help in making planning and policy development for restoring and enhancing the carrying capacity of land and sustainability of the environment in a city landscape.