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La-doped ZnO nanoflower as photocatalyst for methylene blue dye degradation under UV irradiation
Hemalatha, P.,Karthick, S. N.,Hemalatha, K. V.,Yi, M.,Kim, H. J.,Alagar, M. Springer Science + Business Media 2016 Journal of materials science Materials in electron Vol.27 No.3
<P>Lanthanum doped ZnO flower-like structured nanoparticles were synthesized through microwave assisted sol-gel technique. X-ray diffraction, scanning electron microscopy, transmission electron microscopy analysis confirmed the size, structural morphology and successful compound formation of the samples. The band gap was calculated from Tauc's plot using UV-Vis spectroscopy data. Lanthanum doped ZnO nanoparticles were used for the photocatalytic degradation of methylene blue dye under UV light irradiation. Compared to pure ZnO sample, La-doped samples exhibited higher photocatalytic dye degradation under UV light irradiation with short time duration. Among the different amounts of dopant, 3 mol% La-doped ZnO nano rods showed the highest degradation with short time UV light irradiation (60 min). Other factors such as particle size, morphology and defects also affect the photocatalytic activity. In our study, the main factor that influence photocatalytic activity is the separation of photo induced electron-hole pair due to defects formation in the sample. The 3 mol% sample has the appropriate electron-hole separation due to defects compared to pure ZnO. The influence of defects on the photocatalytic activity of all samples has been revealed using photoluminescence spectroscopy analysis. Furthermore, the effect of various operational parameters such as photocatalyst quantity, dye concentration and dopant concentrations were also optimized.</P>
EERA: ENHANCED EFFICIENT ROUTING ALGORITHM FOR MOBILE SENSOR NETWORK
Hemalatha, S,Raj, E.George Dharma Prakash International Journal of Computer ScienceNetwork S 2022 International journal of computer science and netw Vol.22 No.9
A Mobile Sensor Network is widely used in real time applications. A critical need in Mobile Sensor Network is to achieve energy efficiency during routing as the sensor nodes have scarce energy resource. The nodes' mobility in MWSN poses a challenge to design an energy efficient routing protocol. Clustering helps to achieve energy efficiency by reducing the organization complexity overhead of the network which is proportional to the number of nodes in the network. This paper proposes"EERA: Energy Efficient Routing Algorithm for Mobile Sensor Network" is divided into five phases. 1, Cluster Formation 2.Cluster head and Transmission head selection 3.Path Establishment / Route discovery and 4,Data Transmission. Experimental Analysis has been done and is found that the proposed method performs better than the existing method with respect to four parameters.
Hemalatha Parangusan,Jolly Bhadra,Zubair Ahmad,Ali S. M A Al-Maadeed,Abdulaziz M. A A Al-Mohannadi,Noora Al-Thani 한국섬유공학회 2022 Fibers and polymers Vol.23 No.5
Clean drinking water has been a vital topic of research in modern world, this makes efficient water purification asthe latest demand. The research and development in the field of filtration technology has revitalize considerable awareness indifferent engineered methods and nanomaterials. In this work, a hydrophobic composite fibers was successfully prepared byincorporating ZnO nanofiller into polyvinylidene fluoride (PVDF) using an electrospinning method for organic dyedegradation and oil absorption applications. The hydrothermal method was used to prepare pure ZnO. The structuralproperties of PVDF/ZnO composite fibers and pure ZnO were studied using the X-ray diffraction technique (XRD). TheSEM image of pure ZnO shows a flower-like structure and the composites exhibited the structure of the fibers. The averagefiber diameter of the pure PVDF fiber was around 625 nm and the PVDF/ZnO composite fiber was around 485 nm,respectively. Finally, the prepared fibers were tested for oil absorption and the photocatalytic degradation of organic dyes. The photocatalytic activity of PVDF/ZnO was evaluated by the degradation of Azocarmine G (AZG) and Malachite green(MG) dye under sunlight irradiation. The results showed that 85 % of AZG and 90 % of MG dye could be degraded within120 min and 240 min. It was found that the PVDF/ZnO composite fiber was hydrophobic (135 °) under water. Good oilabsorption efficiency (115 %) was achieved using PVDF/ZnO composite fibers. The results shows that the preparedcomposite fibers can be used to absorb oil and degrade organic contaminants. This cost-effective, easy operation, reusability,and efficiency of the PVDF/ZnO fiber mats could be potentially useful for water treatment and oil recovery.
Role of ceria in CO<sub>2</sub> adsorption on NaZSM-5 synthesized using rice husk ash
Hemalatha, P.,Bhagiyalakshmi, M.,Ganesh, M.,Palanichamy, M.,Murugesan, V.,Jang, H.T. Korean Society of Industrial and Engineering Chemi 2012 Journal of industrial and engineering chemistry Vol.18 No.1
Ceria (3, 5, 7, 11, 19wt%) impregnated NaZSM-5 was synthesized and studied for adsorption of CO<SUB>2</SUB>. They were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDS), CO<SUB>2</SUB>-temperature programmed desorption (CO<SUB>2</SUB>-TPD) and Brunauer-Emmett-Teller (BET) techniques. The heat of the reaction (ΔH<SUB>r</SUB>) derived from differential scanning calorimetry (DSC) analysis was 490Btu/lb. XRD analysis showed a decrease in the intensity of patterns with the increase in the ceria loading but crystallization of ceria to larger size was clearly evident for 11 and 19% loading. The surface area decreased for 3 and 5% loading, but increased for 7, 11 and 19% loading illustrating difference in dispersion. The maximum adsorption capacity of CeO<SUB>2</SUB>(5%)/NaZSM-5 was 130mg/g of sorbent. Extraction of silica from the agricultural waste, rice husk, and its use in the zeolite synthesis was an advantage in this study. Hence, from the study it was concluded that ceria impregnated NaZSM-5 could be treated as a novel material for CO<SUB>2</SUB> adsorption, as they were regenerable and recyclable. This study can also be applied to all other zeolites.
S HEMALATHA,Lingaraju DUMPALA,B BALAKRISHNA 한국해운물류학회 2018 The Asian journal of shipping and Logistics Vol.34 No.2
In today’s competitive business environment, evaluation and analysis of service quality of service organizations is vital to further improve quality of providing service by the organizations. The present study focuses on the evaluation of service quality of container terminal operators as these organizations play a major role in increase of national economy. Service quality evaluation process makes use of SERVQUAL tool for service quality evaluation of container terminal operators. Customized questionnaire for 20 enablers of 5 dimensions of service quality are prepared and distributed to 25 customers of 12 container terminal operators in India. Weights of dimensions and enablers pertaining to service quality of container terminal operators are determined through Attribute Hierarchy Model (AHM) to avoid consistency check, present in standard AHP method. TOPSIS and GRP methods are implemented to evaluate service quality of container terminal operators and composite rank is arrived. Consistency in the ranking is observed in the ranking patterns obtained by the proposed methods.
Rayleigh wave at imperfectly corrugated interface in FGPM structure
K. Hemalatha,S. Kumar,A. Akshaya Techno-Press 2023 Coupled systems mechanics Vol.12 No.4
The Rayleigh wave propagation is considered in the structure of the functionally graded piezoelectric material (FGPM) layer over the elastic substrate. The elastic substrate loosely bonds the layer through a corrugated interface, whereas its upper boundary is also corrugated but stress-free. Additionally, the solutions for the FGPM layer and substrate are derived using the fundamental variable separable approach to convert the partial differential equation to an ordinary differential equation. The results with boundary conditions lead to dispersion relations for the electrically open and electrically short cases in the determinant form. The outcomes have been numerically analyzed using a specific model. The findings were presented in the form of graphs, which were created using Mathematica 7. Graphs are plotted for variations in wavenumber and phase velocity. The outcomes may help measure interface defects and design Surface Acoustic Wave (SAW) devices.
Ch. Hemalatha,K. Suresh Babu,G. Narsinga Rao 한국자기학회 2020 Journal of Magnetics Vol.25 No.3
Pure and Mn (2.5 %, 5 % and 10 %) doped CuO nanoparticles were synthesized via chemical process of ultrasonic spray pyrolysis method. The crystal structure and grain size of the particles were determined using XRD. The optical properties of the samples were investigated using UV- Visible spectroscopy. The SEM micrographs revealed the surface morphology of sphere-shaped particles in all samples. The ZFC magnetization exhibits a sharp peak at 32 K and the FC magnetization saturated below this peak temperature. This is a characteristic feature of typical spin-glass behavior. In addition, the AC conductivity curves show an increasing conductivity value with increasing Mn content. The enhanced conductivity is due to the Mn doping in CuO induce defects in grain boundary.