Browse Items (5511 total)
Sort by:
-
N-tier modelling of robust key management for secure data aggregation in wireless sensor network
Security problems in Wireless Sensor Network (WSN) have been researched from more than a decade. There are various security approaches being evolving towards resisting various forms of attack using different methodologies. After reviewing the existing security approaches, it can be concluded that such security approaches are highly attack-specific and doesnt address various associated issues in WSN. It is essential for security approach to be computationally lightweight. Therefore, this paper presents a novel analytical modelling that is based on n-tier approach with a target to generate an optimized secret key that could ensure higher degree of security during the process of data aggregation in WSN. The study outcome shows that proposed system is computationally lightweight with good performance on reduced delay and reduced energy consumption. It also exhibits enhanced response time and good data delivery performance to balance the need of security and data forwarding performance in WSN. 2019 Institute of Advanced Engineering and Science. -
N?-[(1E)-1-(2-Fluorophenyl)ethylidene]pyridine-3-carbohydrazide
The title compound, C14H12FN3O, adopts an E conformation with respect to the azomethine double bond whereas the N and methyl C atoms are in a Z conformation with respect to the same bond. The ketonic O and azomethine N atoms are cis to each other. The non-planar molecule [the dihedral angle between the benzene rings is 7.44(11)] exists in an amido form with a C=O bond length of 1.221(2) In the crystal, a bifurcated N - H(O,N) hydrogen bond is formed between the amide H atom and the keto O and imine N atoms of an adjacent molecule, leading to the formation of chains propagating along the b-axis direction. Through a 180 rotation of the fluorophenyl ring, the F atom is disordered over two sites with an occupancy ratio of 0.632(4):0.368(4). Sreeja et al. 2014. -
N?-[(E)-1-(2-fluorophenyl)ethylidene]pyridine-4-carbohydrazide
The title compound, C14H12FN3O, adopts an E conformation with respect to the azomethine bond. The pyridyl and fluorobenzene rings make dihedral angles of 38.58(6) and 41.61(5) respectively with the central C(=O)N2CC unit, resulting in a non-planar molecule. The intermolecular interactions comprise two classical N - H?O and N - H?N hydrogen bonds and four non-classical C - H?O and C - H?F hydrogen bonds. These interactions are augmented by a weak ?-? interaction between the benzene and pyridyl rings of neighbouring molecules, with a centroid-centroid distance of 3.9226(10) This leads to a three-dimensional supramolecular assembly in the crystal system. The F atom is disordered over two sites in a 0.559(3): 0.441(3) ratio, through a 180 rotation of the fluorobenzene ring. 2014 CrossMark. -
N?-[(E)-2-Fluorobenzylidene]benzohydrazide
The asymmetric unit of the title compound, C14H 11FN2O, contains two independent molecules, both of which adopt the E conformation with respect to the azomethine C=N bond. The molecules are non-planar, with dihedral angles of 26.92 (12) and 11.36 (11) between the benzene and phenyl rings. In the crystal, molecules are linked through N-H?O=C and N-H?N hydrogen bonds into chains along [101]. C-H?O contacts link these chains into layers parallel to (001). The three-dimensional crystal packing is stabilized by ?-? interactions, the shortest separation between the centroids of benzene rings being 3.884 (1) -
N?-[(E)-Furan-2-ylmethylidene]-4-hydroxybenzohydrazide
The title compound, C12H10N2O3, exists in the E conformation. The five-membered ring and the phenyl rings form dihedral angles of 36.73 (10) and 12.22 (10), respectively, with the central C(=O)N2C unit. The crystal packing is dominated by strong N - H?O and O - H?N hydrogen bonds. Together with weaker C - H?O interactions, these establish a three-dimensional supramolecular network. -
N'-[(1E)-1-(2-Fluorophenyl)Ethylidene]Pyridine-3-Carbohydrazide /
Acta Crystallographica Section E, Vol-E70(o115), ISSN-1600-5368 -
N'-[(E)-1-(2-Fluorophenyl)ethylidene]pyridine-4-carbohydrazide
Acta Crystallographica Section E, Vol-E70, ISSN-1600-5368 -
N'-[(E)-Furan-2-Ylmethylidene]-4-Hydroxybenzohydrazide
Acta Crystallographica Section E, Vol-E70(o242), ISSN-1600-5368 -
Na+ doped CuO: A new paradigm electrode material for high performance supercapacitors
This study investigates the influence of sodium doping on the properties of cupric oxide (CuO) thin films synthesized via spray pyrolysis. Comprehensive characterization was conducted using X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDAX), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), Raman spectroscopy, Hall effect measurements, and electrochemical studies. All films exhibited p-type conductivity, with an optical band gap variation from 1.53 to 1.73 eV. XRD analysis confirmed the dominance of monoclinic CuO, with minor phases of Cu2O and Cu4O3. EDAX and XPS verified the incorporation of Cu, O, and Na elements. FESEM revealed a densely packed morphology with uniform particle distribution and rough surfaces in the electrically optimized film. The Raman spectra of doped samples showed increased intensity and sharpness, attributed to Na + ion-induced polarizability enhancement. Hall effect measurements indicated a tenfold decrease in carrier concentration and a more than tenfold increase in mobility upon sodium doping. Films doped with 4 at.% sodium exhibited the lowest resistivity. Additionally, Na doping enhanced the electrochemical performance of CuO. These findings demonstrate that sodium doping significantly enhances the electrical, optical and electrochemical properties of CuO thin films, making them suitable for applications in optoelectronic devices and supercapacitors. 2024 Elsevier Ltd and Techna Group S.r.l. -
Nano Zinc Oxide Particle Synthesis from Bio-Waste Selaginella willdenowii Leaf Extract: A Multi-Faceted Approach for Environmental and Biomedical Applications
Selaginella willdenowii, a commonly used greenhouse fern, was often used as a biowaste to synthesize zinc oxide nanoparticles (ZnO NPs) in an eco-friendly and cost-effective way. UV-Visible spectra studies were carried out to confirm the synthesis of S. willdenowii-mediated ZnO NPs (SW-ZnO NPs), and a peak at 367nm with a sharp band gap of 3.415eV was observed. The X-ray diffraction analysis indicated that the crystalline size of the synthesized SW-ZnO NPs was 11.971nm. The phytochemicals present in the extracts and the compounds involved in the reduction of metal to nanoparticles were determined by Fourier Transform Infrared analysis. Scanning electron microscopy was utilized to analyze the surface morphology and size of the obtained SW-ZnO NPs. The examination revealed that they exhibited a hexagonal shape, with an average size falling within the range of 17-23nm. Under ultra-violet light, reactive blue 220 and reactive yellow 145 dyes showed 78.06% and 60.14% degradation, showing potential photocatalytic degradation activity. The synthesized SW-ZnO NPs also exhibited antimicrobial activity against bacterial strains (Escherichia coli and Bacillus subtilis) and fungal cultures (Candida tropicalis and Candida albicans) showed cytotoxic activity against Hep-G2 cell lines. Our results suggest the green synthesized SW-ZnO NPs have potential photocatalytic, antimicrobial and cytotoxic potential. 2024 World Scientific Publishing Company. -
Nano- from nature to nurture: A comprehensive review on facets, trends, perspectives and sustainability of nanotechnology in the food sector
Nanotechnology has underpinned vital progress in current research and has immensely promoted the food production chain. This review projected the critical intervention of nano-based technologies like modern advancements of nano-based biosensors in detecting mycotoxins, microbial contaminations, antibiotics, pesticides, food additives, and dyes. It also highlighted the starring roles of nanotechnology in terms of active, intelligent food packaging and food safety. These approaches have certainly intensified the strength of food processing technology and improved food quality and maintenance standards during shelf life. Apart from these trending facets, this review throw light on the utilisation of food waste for the biogenic synthesis of nanoparticles and the application of nano-based materials for the recycling process in food production units to ensure a complete cleaner technology. However, monitoring the chronic exposure of food contact nanomaterials should be critically evaluated to ensure food safety. Nanotechnology embraced an influential role in the food sector by providing effective avenues for energy conservation, sustainability, and cues to improve the capital funds well. 2021 Elsevier Ltd -
Nano-architectured polypyrrole based magnetic nanocatalyst for the N- arylation of imidazoles and fused imidazoles
A new magnetically recoverable polypyrrole supported copper based nanocatalyst was synthesized, characterized with various analytical techniques like Fourier-transform infrared spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive X-ray analysis (EDX), High Resolution Transmission Electron Microscopy (HRTEM), Thermogravimetric analysis (TGA), Vibrating Sample Magnetometry (VSM), and Inductively coupled plasma atomic emission spectroscopy (ICP-AES) analysis. The loading of copper on the surface of the catalyst was found to be 4.23 wt%. The application of the synthesized nanocatalyst was checked for the N-arylation of imidazoles. Excellent catalytic performance was obtained with easy recoverability and reusability upto six cycles. The current green protocol makes it environmentally beneficial for scale-up industries. 2025 Elsevier B.V. -
Nanoencapsulation of Ru(p-cymene) Complex Bearing Ginger-based Natural Product into Liposomal Nanoformulation to Improve Its Cellular Uptake and Antiproliferative Activity
The organometallic compounds are prospective candidates in the row of developing metallochemotherapeutics with the aim of overcoming the limitations of platinum drugs. In order to explore the anticancer properties of organometallic compounds with the natural medicines, two Ru(II)-p-cymene complexes containing the natural products, viz., 6-gingerol (6G) and benzylated-6-gingerdione (B-6GD) have been synthesized and characterized well. The phenolic group of the Ru(6G) complex facilitates its higher cell-free antioxidant activity than its analogue complex. Also, the same complex shows higher cytotoxicity toward A549 lung and HeLa-S3 cervical cancer cells than the Ru(B-6GD) complex but lower cytotoxicity toward A2058 metastatic melanoma cancer cells. Both complexes are shown to easily accumulate in melanoma cancer cells, and their degree of cytotoxicity in the same cells is found to be positively correlated with cell uptake. The cytotoxicity of complexes arises from their intracellular activity, mainly due to the induction of singlet oxygen production in cancer cells. The subcellular fractionation study shows that mitochondria and ER-Golgi membranes might be their predominant targets. Also, the mechanistic investigation revealed that Ru(B-6GD) induces caspase-dependent non-apoptotic cell death whereas Ru(6G) can induce caspase-independent non-apoptotic cell death. Furthermore, both complexes are found to moderately alter the adhesion properties of cancer cells, which is beneficial for antimetastatic treatment. Despite the potential pharmacological activity, Ru(6G) is encapsulated into polymer-supported liposomes to reduce its toxicity and further improve its anticancer potency. The ?-conjugated yne-ene chain of polydiacetylene aids in the development of a stable nanoformulation, which achieved a slow release of the complex. Most importantly, the cancer cell uptake of the liposome-encapsulated Ru(6G) complex is 20 times enhanced and the total ROS formation in cancer cells is significantly increased compared to the non-encapsulated complex. However, the nanoformulation does not alter the antimetastatic potency of the encapsulated complex. 2022 American Chemical Society. All rights reserved. -
Nanofluid flow past a vertical plate with nanoparticle aggregation kinematics, thermal slip and significant buoyancy force effects using modified Buongiorno model
The flow of ethylene glycol-based titania nanoliquid passing through a vertical plate induced by significant buoyancy forces (nonlinear convection) is analyzed with quadratic thermal radiation and considering the aggregation kinematics of the nanoparticles. The nanoliquid is modeled accounting for thermo-migration, Brownian motion, and the effectual thermophysical properties. The realistic zero mass flux and thermal slip conditions are considered on the surface of the plate. In addition, the mechanisms of exponential space-related heat source (ESHS) and thermal-based heat source (THS) are incorporated. The finite-difference technique-based bvp5c routine is used to obtain the numerical solution of thenonlinear system of equations. The effects of the parameters are examined on the dimensionless profiles of velocity, temperature, heat transport rate, the volume fraction of nanoparticles, and streamlines. It was found that the aggregation of nanoparticles significantly advances the temperature field while the velocity field is reduced. The ESHS and THS modulations improve the thickness of the thermal boundary layer. The quadratic thermal convection aspect improves the velocity of nanoliquid. Furthermore, the effects of quadratic thermal radiation assist the growth of the thermal boundary layer. The present results are relevant to various thermal systems including flat plate solar collectors, heat exchangers, and nuclear reactors. 2021 Informa UK Limited, trading as Taylor & Francis Group. -
Nanofluid flowing over a rotating disk that is stretching and permeable: An unsteady model
The model presented in this paper deals with the investigation of the unsteady laminar flow past a stretchable disk. The nanofluids Al2O3/H2O and Cu/H2O are considered for the analysis where the thermal characteristics and flow behavior of these nanofluids are compared. In addition, the system is subjected to the suction force that has significant impacts on velocity of the nanofluid flow. Further, the nanoparticle solid volume fraction is another important parameter that is discussed which has a prominent role on both profiles of the nanofluid. Furthermore, the investigated mathematical model is framed using PDEs that are transformed to ODEs using suitable transformations. The system of equations obtained in this regard is solved by employing the RKF-45 numerical method where the results are obtained in the form of graphs. Various nanofluids flow parameters arise in the study and the impact of all these parameters has been analyzed and interpreted. Some of the major outcomes are that the higher values of nanoparticle solid volume fraction enhance the temperature while it decreases velocity of the flow. The comparison of flow of the two nanofluids concluded that aluminawater nanofluid has a better velocity while the copperwater nanofluid has a better thermal conductivity. World Scientific Publishing Company. -
Nanoparticle aggregation effects on radiative heat transport of nanoliquid over a vertical cylinder with sensitivity analysis
A sensitivity analysis is performed to analyze the effects of the nanoparticle (NP) aggregation and thermal radiation on heat transport of the nanoliquids (titania based on ethylene glycol) over a vertical cylinder. The optimization of heat transfer rate and friction factor is performed for NP volume fraction (1% ? ? ? 3%), radiation parameter (1 ? Rt ? 3), and mixed convection parameter (1.5 ? ? ? 2.5) via the face-centered central composite design (CCD) and the response surface methodology (RSM). The modified Krieger and Dougherty model (MKDM) for dynamic viscosity and the Bruggeman model (BM) for thermal conductivity are utilized to simulate nanoliquids with the NP aggregation aspect. The complicated nonlinear problem is treated numerically. It is found that the temperature of nanoliquid is enhanced due to the aggregation of NPs. The friction factor is more sensitive to the volume fraction of NPs than the thermal radiation and the mixed convection parameter. Furthermore, the heat transport rate is more sensitive to the effect of radiative heat compared with the NP volume fraction and mixed convection parameter. 2021, Shanghai University and Springer-Verlag GmbH Germany, part of Springer Nature. -
Nanoparticle aggregation kinematics on the quadratic convective magnetohydrodynamic flow of nanomaterial past an inclined flat plate with sensitivity analysis
The study focuses on the aggregation kinematics in the quadratic convective magneto-hydrodynamics of ethylene glycol-titania ((Formula presented.)) nanofluid flowing through an inclined flat plate. The modified Krieger-Dougherty and Maxwell-Bruggeman models are used for the effective viscosity and thermal conductivity to account for the aggregation aspect. The effects of an exponential space-dependent heat source and thermal radiation are incorporated. The impact of pertinent parameters on the heat transfer coefficient is explored by using the Response Surface Methodology and Sensitivity Analysis. The effects of several parameters on the skin friction and heat transfer coefficient at the plate are displayed via surface graphs. The velocity and thermal profiles are compared for two physical scenarios: flow over a vertical plate and flow over an inclined plate. The nonlinear problem is solved using the RungeKutta-based shooting technique. It was found that the velocity profile significantly decreased as the inclination of the plate increased on the other hand the temperature profile improved. The heat transfer coefficient decreased due to the increase in the Hartmann number. The exponential heat source has a decreasing effect on the heat flux and the angle of inclination is more sensitive to the heat transfer coefficient than other variables. Further, when radiation is incremented, the sensitivity of the heat flux toward the inclination angle augments at the rate 0.5094% and the sensitivity toward the exponential heat source augments at the rate 0.0925%. In addition, 41.1388% decrement in wall shear stress is observed when the plate inclination is incremented from (Formula presented.) to (Formula presented.). IMechE 2021. -
Nanosheets of nickel, cobalt and manganese triple hydroxides/oxyhydroxides as efficient electrode materials for asymmetrical supercapacitors
Transition metals play a significant role in energy storage applications mainly as electrode materials in supercapacitors. In this work, triple hydroxide/oxyhydroxide nanosheets of a nickel, cobalt and manganese (NCM) composite were electrochemically deposited on carbon cloth (CC) and used as electrode materials in supercapacitors. In a three electrode system the composite delivered a specific capacitance of 707 F g -1 at a current density of 3 A g -1 which retained its stability even at a higher current density of 50 A g -1 . An asymmetric supercapacitor (ASC) was assembled and characterized using NCM as the positive electrode, activated carbon as the negative electrode and Whatman filter paper soaked in KOH as the separator. The device operated in a working potential window of 1.75 V and it delivered a power density of 13.12 kW kg -1 and an energy density of 23.7 W h kg -1 . 2019 The Royal Society of Chemistry. -
Nanostructured ZnCo2S4@metal organic frameworks composite for supercapacitor by ultrasonication supported hydrothermal reaction
Electrode materials for supercapacitors, sensors, and battery applications were frequently manufactured using the chemistry of metal organic framework nanostructured materials. These materials have three-dimensional networks between organic linkers and metal precursors thanks to diverse chemical alterations. Due to their enhanced surface characteristics, porous nature, and strong connecting organic molecules for numerous possible applications, MOFs have a wide range of uses. In this study, we used a sonicated enhanced hydrothermal reaction to fabricate ZnCo2S4 and ZnCo2S4 on the metal organic framework composite materials. Raman, FTIR, XRD, XPS, SEM, and SEM-EDS tests were utilized to confirm the composite's structural and morphological features. With 1 M KOH electrolyte, composite electrodes for supercapacitor fabrication were produced. The composite electrodes have a stability under cycles count of 5000 and a capacitance of 550 F/g at a density of 1 A/g. 2024 Elsevier B.V. -
Narrating Trauma as Victims of Human Trafficking in China: A Study on Select North Korean Memoirs
The memoirs titled In Order to Live; A North Korean Girl's Journey, to Freedom and; A Thousand Miles to Freedom: My Escape from North Korea are written by Yeonmi Park and Eunsun Kim two women who managed to escape from North Korea. They went through an experience of being forced into labour in China as victims of trafficking. In their memoirs these authors vividly depict the pain that comes with being exploited. The main aim of this study is to analyse how memoirs can effectively address the issue of trafficking. These remarkable women skilfully use the memoir genre to make a personal plea for action. They strategically make choices appeal to readers emotions openly share their distressing experiences and support their stories with research and evidence that connect their experiences with the broader problem of human trafficking in China. This study clearly shows that both these memoirs emphasize the importance of the memoir genre in advocating for rights. It also highlights how survivor memoirs have the potential to inspire advocacy and involvement, in combating trafficking. 2025 Sciedu Press. All rights reserved.