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Effect of Sintering Temperature on the Micro Strain and Magnetic Properties of Ni-Zn Nanoferrites
D. Venkatesh,M. Siva Ram Prasad,B. Rajesh Babu,K. V. Ramesh,K. Trinath 한국자기학회 2015 Journal of Magnetics Vol.20 No.3
In this study, nanocrystalline ferrite powders with the composition Ni0.5Zn0.5Fe₂O₄ were prepared by the autocombustion method. The obtained powders were sintered at 800℃, 900℃ and 1,000℃ for 4 h in air atmosphere. The as-prepared and the sintered powders were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and magnetization studies. An increase in the crystallite size and a slight decrease in the lattice constant with sintering temperature were observed, whereas microstrain was observed to be negative for all the samples. Two significant absorption bands in the wave number range of the 400 cm<SUP>?1</SUP> to 600 cm<SUP>?1</SUP> have been observed in the FT-IR spectra for all samples which is the distinctive feature of the spinel ferrites. The force constants were found to vary with sintering temperature, suggesting a cation redistribution and modification in the unit cell of the spinel. The M-H loops indicate smaller coercivity, which is the typical nature of the soft ferrites. The observed variation in the saturation magnetization and coercivity with sintering temperature has been attributed to the role of surface, inhomogeneous cation distribution, and increase in the crystallite size.
Bathina Venkateswararao,Devarapalli Ramesh,García Márquez Fausto Pedro 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.3
An electrical power system is a vast interlocked network that needs a vigilant design to sustain the system with an uninterrupted power flow operation without any restrictions, called optimal power flow (OPF). OPF problem requires robust and fast optimization techniques to volve it due to its complexity. Cuckoo Search (CS) is one method that is being applied in OPF problems, and it has many advantages, e.g., ease use and littler tuning parameters. But it is not good enough, falling into local optimal resolutions and slow converges. Therefore, recently developed Grey Wolf Optimization (GWO) algorithm is used to solve OPF, but it has low accuracy and inadequate local searching ability. To overcome these problems, this paper proposed to combine CS with GWO to create a novel the Hybrid algorithm, called here HCSGWO. The main objective is to deduce the emission, true power generation cost, true power losses, and voltage stability, being a multi-objective problem. THCSGWO are validated by solving the OPF problem considering the calssic IEEE57 bus system. The results are compared with GWO and other algorithms employed in the literature.
Daniel Popa,Jayapal Ramesh,Shajan Peter,C. Mel Wilcox,Klaus Mönkemüller 대한소화기내시경학회 2014 Clinical Endoscopy Vol.47 No.1
Self-expanding metal stents are a useful therapy to palliate malignant and benign luminal gastrointestinal obstruction. Self-expanding metal stents has been widely reported for colonic, esophageal, and gastric obstruction. However, endoscopic delivery and placement to the small bowel is more challenging and difficult. This case illustrates the usefulness and technical advantages of the balloon-overtube and enteroscopy technique for the palliative treatment of neoplastic stenosis affecting the small intestine.
Ramesh M,Sujatha C. M 대한전자공학회 2018 IEIE Transactions on Smart Processing & Computing Vol.7 No.2
The current diagnostic evaluation criteria for Alzheimer’s disease (AD) are restricted to cognitive deficits, and less consideration is given to AD-related noncognitive, behavioral, and psychological symptoms of dementia. Vascular deterioration in AD subjects manifests neuropsychiatric symptoms (NPS). Early anxiety and depression are associated with cognitive decline. The brainstem undergoes deformation during the initiation of AD due to NPS. In this work, structural deformation of the brainstem is analyzed using Lattice Boltzmann criterion-based hybrid level set method (LSM) and fourth-order diffusion filtering. Contour and skeletal-based shape measures are extracted and analyzed using multilayer perceptron (MLP). Results show that the fourth-order diffusion filter provides strong edges, which aids in accurate segmentation. The Lattice Boltzmann criterion-based hybrid LSM is able to delineate the whole brainstem. Hough transform statistics (HTS) obtained from the segmented brainstem describe the geometric properties of the boundary of the brainstem. Eigen space values identify the skeletal variations of the brainstem for normal, Mild Cognitive Impairment (MCI), and AD subjects. Both HTS and eigen space features are found to represent better differentiation between normal, MCI, and AD subjects with a significance of p<0.05. It is observed that Hough transform–based statistical values have the ability to better discriminate the structural deformity of the brainstem with classification accuracies of 73%, 68%, and 71% for normal–MCI, MCI–AD, and normal–AD classifications, respectively, using MLP. Thus, this analysis identifies the presence of structural abnormality in the brainstem during the progression of AD, and therefore, this analysis could aid in early diagnosis of AD.
Development of New Productive Bivoltine Silkworm (Bombyx mori L.) Hybrid, APS83 X APS102
M. Ramesh Babu,H. Lakshmi,J. Prasad,J. Seetharamulu,Chandrashekharaiah 한국잠사학회 2005 International Journal of Industrial Entomology Vol.11 No.1
Successful silkworm breeding attempts were made at Andhra Pradesh State Sericulture Research and Development Institute (APSSRDI), Hindupur, India in developing productive bivoltine silkworm hybrids.One hundred hybrid combinations involving 10 parents (five each of oval and peanut) were evaluated in complete diallel pattern and identified the combination APS83 × APS102 as most promising. This hybrid showed economic merit for the characters fecundity (524 eggs/laying), pupation percentage (96.0%), cocoon yield per 10,000 larvae by weight (19.0 kg), cocoon weight (1.85 g), shell weight (41.7 cg), shell ratio (22.5%), filament length (1,004 m), reelability (88.4%),raw silk recovery (18.4%) and neatness (92 point) over the control hybrid APS9 × APS8. The breeding process and identification of APS83 × APS102 is discussed in the paper.
Ramesh Babu M.,Lakshmi H.,Prasad J.,Seetharamulu Seetharamulu,Chandrashekharaiah J. Korean Society of Sericultural Science 2005 International Journal of Industrial Entomology Vol.11 No.1
Successful silkworm breeding attempts were made at Andhra Pradesh State Sericulture Research and Development Institute (APSSRDI), Hindupur, India in developing productive bivoltine silkworm hybrids. One hundred hybrid combinations involving 10 parents (five each of oval and peanut) were evaluated in complete diallel pattern and identified the combination APS$_{83}$ $\times$ APS$_{102}$ as most promising. This hybrid showed economic merit for the characters fecundity (524 eggs/laying), pupation percentage (96.0$\%$), cocoon yield per 10,000 larvae by weight (19.0 kg), cocoon weight (1.85 g), shell weight (41.7 cg), shell ratio (22.5$\%$), filament length (1,004 m), reelability (88.4$\%$), raw silk recovery (18.4$\%$) and neatness (92 point) over the control hybrid APS$_{9}$ $\times$ APS$_{8}$ The breeding process and identification of APS$_{83}$ $\times$ APS$_{102}$ is discussed in the paper.
Magnetoelectric complex-oxide heterostructures
Ramesh, R.,Zavaliche, F.,Chu, Y. H.,Martin, L. W.,Yang, S. Y.,Cruz, M. P.,Barry, M.,Lee, K.,Yang, P.,Zhan, Q. Taylor and Francis 2007 Philosophical magazine letters Vol.87 No.3
<P> A short review of recent progress in the field of multiferroic thin films and heterostructures is given. We focus on the bismuth iron oxide system due to its desirable properties, namely high ferroelectric Curie temperature and antiferromagnetic Neel temperature. Epitaxial growth of this model system in various crystallographic orientations has conclusively demonstrated the large ferroelectric polarization in this system. Piezoforce microscopy reveal a complex domain structure, especially on (100) SrTiO3 substrates. Electrical switching experiments show the co-existence of 71°, 109° and 180° domain switching mechanisms in such films. Preliminary work has shown promise for electrically controllable exchange bias in ferromagnet-multiferroic heterostructures.</P>
M. Ramesh,K. A. Sundararaman,M. Sabareeswaran,R. Srinivasan 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.23 No.12
In this research paper, a methodology is proposed by combining taguchi’s parametric design, hybrid artificial neural network–particle swarm optimization (ANN–PSO) and evolutionary techniques to optimize the fixture layout by minimizing the maximum workpiece deformation on a 2D fixture workpiece system in end milling operation. Taguchi’s parametric design with five levels is utilized iteratively to estimate the potential range to place the fixture elements around the workpiece using the data obtained from finite element method. The hybrid ANN–PSO model is developed to predict the maximum workpiece deformation within the potential range in which PSO is utilized to optimize the weights and biases of the network. The diversity of data used for training the model is ensured by combining the experimental conditions of central composite design and Box Behnken design of response surface methodology. The developed model is tested using root mean square error, which exhibited better prediction accuracy. The hybrid ANN–PSO model is then optimized by genetic algorithm (GA) and PSO. The results clearly indicate that the PSO is capable of producing better fixture layouts with 0.1936% of superiority in solution quality than GA. Hence, the proposed approach is more viable to design the improved fixture layout with huge reduction in time and computational complexity.
M. Amuthasurabi,J. Chandradass,V Ramesh Babu,P.Baskara Sethupathi,M. Leenus Jesu Martin 한양대학교 세라믹연구소 2017 Journal of Ceramic Processing Research Vol.18 No.11
We report on the performance of the thin film transistors (TFTs) using ZnO as an active channel layer grown by using radio frequency (rf) magnetron sputtering technique. The TFT device structure used in this study was a bottom gate type, which consists of SiNx as a gate insulator and indium tin oxide (ITO) as a gate deposited onto corning glass substrates. Electrical characteristics of the device showed clear saturation region without any output current degradation due to self heating effect. These ZnO TFTs had a saturation field effect mobility of about 2.14 cm2/Vs, an on to off ratio of greater than 105, the off current of less than 10−10 A and a threshold voltage of 15 V at a maximum device processing temperature of 350 oC. This TFT had a channel width of 300 μm and channel length of 30 μm. Moreover, the SiNx dielectric layer was found to be optimum for the high performance ZnO based TFTs because of the very low leakage current and good interface between the channel layer and gate material.