Cascaded Fuzzy Logic Controlled Modular Multilevel Converter for PV Based DSTATCOM Applications

Umadevi C.,Sundari M. Gnana,Karuvelam P. Subha 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.3

This paper analyses the implementation of modular multi level converter (MMLC) in the application of grid connected Photovoltaic system in an efcient manner. As MMLC exhibits properties of high modularity and scalability, it is highly suitable for the high power applications, which makes MMLC to be preferred in this study as an apt replacement of the conventional DC–DC converters. A unifed control using a cascaded fuzzy logic controller (CFLC) is proposed for both the maximum power point tracking and modular 7 level converter (M7LC) control. The CFLC is analogized with the conventional PI and Fuzzy controllers under both the normal and partial shaded conditions. The entire system is assessed with the aid of using MATLAB simulation. The observed outcomes exhibit that total harmonic distortion (THD) of line current is minimum under all operating conditions when the CFLC is used for M7LC. The prototype of the proposed M7LC with CFLC is implemented in FPGA SPARTAN 6E controller for the experimental validation. The proposed approach delivers lesser THD of 1.02% under normal condition and 1.12% under partial shading condition.

Fluorinated TiO2‑doped, glycine‑functionalized MWCNTs for high‑performance antibacterial agents

Umadevi Mahalingam,Poornima P. Veerabaghu,Sangari Mayavan,Parimaladevi Ramasamy 한국탄소학회 2019 Carbon Letters Vol.29 No.1

Perennial need for bactericides requires cost-effective nanomaterials with strong antibacterial activities even in the absence of external irradiation. Hence, in this work, we have synthesized f-CFT (fluorinated TiO2- doped, glycine-functionalized MWCNTs) and have studied its antibacterial activities. Both gram-negative and gram-positive bacteria were analyzed in the absence of photo-activation. Zone of inhibition of 15 mm for S. aureus, and 11 mm for P. aeruginosa was observed for f-CFT owing to the synergistic bactericidal properties of functionalized MWCNTs, fluorine and nano-TiO2. Anatase phase TiO2 with average crystallite size as 35 nm was observed in XRD. Scanning electron microscopic images showed uniform mixed cubic structures. Hydroxyl groups observed in FT-IR along with the glycine MWCNTs interface aid the inhibition of bacterial growth even in the absence of photo activation. A desired higher gram-positive bacterial inhibition opens new gates for better antibacterial agents.

Data Interpolation and Design Optimisation of Brushless DC Motor Using Generalized Regression Neural Network

Umadevi, N.,Balaji, M.,Kamaraj, V.,Padmanaban, L. Ananda The Korean Institute of Electrical Engineers 2015 Journal of Electrical Engineering & Technology Vol.10 No.1

This paper proposes a generalized regression neural network (GRNN) based algorithm for data interpolation and design optimization of brushless dc (BLDC) motor. The procedure makes use of magnet length, stator slot opening and air gap length as design variables. Cogging torque and average torque are treated as performance indices. The optimal design necessitates mitigating the cogging torque and maximizing the average torque by varying design variables. The data set for interpolation and ensuing design optimisation using GRNN is obtained by modeling a standard BLDC motor using finite element analysis (FEA) tool MagNet 7.1.1. The performance indices of the standard motor obtained using FEA are validated with an experimental model and an analytical method. The optimal design is authenticated using particle swarm optimization (PSO) algorithm and the performance indices of the optimal design obtained using GRNN is validated using FEA. The results indicate the suitability of GRNN as an interpolation and design optimization tool for a BLDC motor.

Fluorinated TiO2‑doped, glycine‑functionalized MWCNTs for high‑performance antibacterial agents

Umadevi Mahalingam1,Poornima P. Veerabaghu,Sangari Mayavan,Parimaladevi Ramasamy 한국탄소학회 2019 Carbon Letters Vol.29 No.1

Perennial need for bactericides requires cost-effective nanomaterials with strong antibacterial activities even in the absence of external irradiation. Hence, in this work, we have synthesized f-CFT (fluorinated TiO2-doped, glycine-functionalized MWCNTs) and have studied its antibacterial activities. Both gram-negative and gram-positive bacteria were analyzed in the absence of photo-activation. Zone of inhibition of 15 mm for S. aureus, and 11 mm for P. aeruginosa was observed for f-CFT owing to the synergistic bactericidal properties of functionalized MWCNTs, fluorine and nano-TiO2. Anatase phase TiO2 with average crystallite size as 35 nm was observed in XRD. Scanning electron microscopic images showed uniform mixed cubic structures. Hydroxyl groups observed in FT-IR along with the glycine MWCNTs interface aid the inhibition of bacterial growth even in the absence of photo activation. A desired higher gram-positive bacterial inhibition opens new gates for better antibacterial agents.

Phytochemical Investigation of the Leaves of Flaveria trinervia

S. Umadevi,G.P. Mohanta,K. Balakrishna,R. Manavalan 한국생약학회 2005 Natural Product Sciences Vol.11 No.1

Phytochemical study of the methanolic extract of Flaveria trinerviaisolation of three constituents characterised as 3,5,7,4tetrahydroxy-6-methoxy flavone (6-methoxy kaempferol),oleanolic acid and β-sitosterol-β-D-glucoside. The identities of the compounds were confirmed by the physicaland spectroscopic data and by comparison with authentic samples.

Data Interpolation and Design Optimisation of Brushless DC Motor Using Generalized Regression Neural Network

N. Umadevi,M. Balaji,V. Kamaraj,L. Ananda Padmanaban 대한전기학회 2015 Journal of Electrical Engineering & Technology Vol.10 No.1

This paper proposes a generalized regression neural network (GRNN) based algorithm for data interpolation and design optimization of brushless dc (BLDC) motor. The procedure makes use of magnet length, stator slot opening and air gap length as design variables. Cogging torque and average torque are treated as performance indices. The optimal design necessitates mitigating the cogging torque and maximizing the average torque by varying design variables. The data set for interpolation and ensuing design optimisation using GRNN is obtained by modeling a standard BLDC motor using finite element analysis (FEA) tool MagNet 7.1.1. The performance indices of the standard motor obtained using FEA are validated with an experimental model and an analytical method. The optimal design is authenticated using particle swarm optimization (PSO) algorithm and the performance indices of the optimal design obtained using GRNN is validated using FEA. The results indicate the suitability of GRNN as an interpolation and design optimization tool for a BLDC motor.

Development of Solid Lipid Nanoparticles Enriched Hydrogels for Topical Delivery of Anti-Fungal Agent

Thiruganesh Ramasamy,Umadevi S Khandasami,Himabindhu Ruttala,Suresh Shanmugam 한국고분자학회 2012 Macromolecular Research Vol.20 No.7

The aim of this study was to formulate and evaluate Ketoconazole-loaded solid lipid nanoparticles (KSLN) for topical application. The purpose of this study was to improve the therapeutic activity of Ketoconazole. KSLN was prepared by a hot homogenization method and characterized for shape, surface morphology, particle size,drug entrapment, cytotoxicity, and rheological analysis. The optimized formulation of solid lipid nanoparticles (SLN) was spherical in shape with a smooth surface and possessed an average size of 172.2±0.75 nm with zeta potential of -44.12±0.76 mV. To guarantee the stability of the desired SLN, they were lyophilized using cryo-protectants. The particle size of the SLN significantly enlarged for formulations which were lyophilized without the cryo-protectants. Cell viability assay performed on National Institute of Health-3-day transfer, inoculum 3×105 cells (NIH-3T3) fibroblast cells showed that properties of the SLN remain unchanged during the process of freeze-drying and were not cytotoxic. An in vitro drug release study showed that KSLN-incorporated hydrogel exhibited a sustained drug release comparing to KSLN dispersion and Ketoconazole loaded hydrogel over a 24 h period. The in vivo studies suggested that the KSLN-incorporated hydrogel was more efficient in the treatment of candidiasis. It may therefore be interpreted that the KSLN-incorporated hydrogel provides a sustained release of Ketoconazole for topical fungal infections and might be a promising delivery system to enhance the therapeutic activity of Ketoconazole.

발달장애인을 위한 커뮤니케이션과 언어 학습 증진을 위한 인공지능 서비스

박찬준,김양희,장윤나,Umadevi G.R,임희석 한국융합학회 2020 한국융합학회논문지 Vol.11 No.6

Children with language developmental disabilities often struggle through their lives from a lot of challenges in everyday life and social activities. They’re often easily deprived of the opportunity to engage in social activities, because they find difficulty in understanding or using language, a core means of communication. With regard to this issue, AAC(Augmentative and Alternative Communication) can be an effective communication tool for children who are suffering from language disabilities. In this paper, we propose a deep learning-based AI service to make full use of the pictogram as an AAC tool for children with language developmental disabilities to improve not only the ability to interact with others but the capacity to understand language. Using this service, we strive to help these children to more effectively communicate their intention or desire and enhance the quality of life. 언어발달 장애를 가진 아동들은 일상생활 및 사회생활에서 많은 어려움을 겪으며 이는 생애 전반을 걸쳐 지속된다. 언어발달 장애 아동들은 의사소통 수단인 언어를 이해하거나 사용하는 데에 어려움을 겪기 때문에 종종 사회적 활동에 참여할 기회를 박탈당하곤 한다. 이와 관련해서 Augmentative and Alternative Communication(AAC, 보완대체 의사소통)는 언어장애를 앓는 이들에게 실직적인 의사소통 수단으로 사용될 수 있다. 본 논문은 픽토그램을 AAC의 수단으로써 최대한 활용하여 언어발달 장애 아동이 타인과 의사소통하고 언어 이해 능력을 향상시킬 수 있도록 돕는 딥러닝 기반 인공지능 서비스를 제안한다. 본 서비스를 통해 언어 문제를 겪고 있는 이들이 자신의 의도 혹은 욕구를 보다 수월하게 표현하여 삶의 질이 향상 될 수 있을 것으로 기대한다.

Treatment of Ovarian Cancer Cells with Nutlin-3 and Resveratrol Combination Leads to Apoptosis via Caspase Activation

Palanisamy Marimuthu,Kamal Kaur,Umadevi Kandalam,Vandana Jasani,Nidha Bukhari,Michelle Nguyen,Alleesa Abdul,Farheen F. Pervez,Appu Rathinavelu 한국식품영양과학회 2011 Journal of medicinal food Vol.14 No.1

The current study was focused on the induction of apoptotic effects of resveratrol along with the combination treatments of nutlin-3 and transforming growth factor-β (TGF-β) against the human ovarian cancer cell line A2780/CP70. To determine the extent of apoptosis following the above-mentioned treatments, we assessed the execution of apoptotic events that proceed via caspase activation and cytochrome c release. We estimated the caspase-3 and -9 activities using a direct enzymatic assay that measures the cleavage of synthetic peptide substrate (N-acetyl-Asp-Glu-Val-Asp-p-nitroanilide). Our experiments showed an increase in caspase-3 and -9 activities in the cells that were treated with the combination of resveratrol (5μM) with nutlin-3 (5μM) or TGF-β (1μg/mL). Since activation of procaspase-3 by caspase-9 requires the release of cytochrome c into the cytoplasm, we measured the levels of cytochrome c in the cytoplasm by western blot experiments. The data indicated a considerable increase in caspase-3 and cytochrome c levels when cells were treated with drugs for 24 hours. Experiments with 4,6′-diamino-2-phenylindole dihydrochloride (DAPI) staining also confirmed the induction of apoptosis in all the above-mentioned treatments done at 24 and 48 hours. These results support our hypothesis that resveratrol combination can induce programmed cell death at doses that

NATURAL CONVECTION AROUND A HEAT CONDUCTING AND GENERATING SOLID BODY INSIDE A SQUARE ENCLOSURE WITH DIFFERENT THERMAL BOUNDARIES

NAGARAJAN NITHYADEVI,PERIYASAMY UMADEVI 한국산업응용수학회 2015 Journal of the Korean Society for Industrial and A Vol.19 No.4

Two-dimensional steady laminar natural convection around a heat conducting and generating solid body inside a square enclosure with different thermal boundaries is performed. The mathematical model is governed by the coupled equation of mass, momentum and energy. These equations are discretized by finite volume method with power-law scheme and solved numerically by SIMPLE algorithm with under-relaxation technique. Effect of Rayleigh number, temperature difference ratio of solid-fluid, aspect ratio of solid-enclosure and the thermal conductivity ratio of solid-fluid are investigated numerically for Pr = 0:7. The flow and heat transfer aspects are demonstrated in the form of streamlines and isotherms respectively.