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Application of Pomegranate Rind Extract for Improvement of Functional Properties of Various Materials—A Critical Review

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Open Journal of Composite Materials 2024年第2期14卷 71-90页

作者： Habeebunissa Nooman Narayanan Gokarneshan Murugan Umamaheswari Muthumani Dhiliphan Kumar usha kumari ratna Jayagopal Lavanya Senthamarai Kannan Umamageshwari Sona Mohandas Anton Zahurudeen Shahanaz Venkatesan Sathya David Piriadarshani Chokkanathan Kayalvizhi Department of Knitwear Design National Institute of Fashion Technology Chennai India Department of Textile Chemistry SSM College of Engineering Komarapallayam India Department of Management Studies Dr. SNS Rajalakshmi College of Arts and Science Coimbatore India Department of Business Administration Kalasalingam Business School Kalasalingam Academy of Research and Education Srivilliputhur India Department of Textiles and Clothing Avinashi Lingam Institute for Home Science and Higher Education for Women Coimbatore India Department of Fashion Design SRM Institute of Science and Technology (Kattankalathur) Chennai India Department of Fashion Design Hindustan Institute of Technology and Science Chennai India Department of Fashion Design SRM Institute of Science and Technology (Ramapuram) Chennai India Department of Mathematics Hindustan Institute of Technology and Science Chennai India Department of Textile Technology Jaya Engineering College Tiruninravur India

Pomegranate rind is abundantly available as a waste material. Pomegranate Rind Extract (PRE) can be applied to cotton fabrics for its natural colours, as a mordanting agent and also for imparting certain functional properties such as fire retardancy and antimicrobial properties. This paper reviews the feasibility of Pomegranate Rind Extract to improve the functional properties of cellulosic fabrics. Studies show that varying concentrations and higher temperatures that were used to apply the extract on the fabric, resulted in enhanced functional properties. At a particular concentration, the treated fabric showed a 15 times lower burning rate in comparison with the control fabric. Also, antimicrobial efficacy has been observed against Gram-positive and Gram-negative bacteria. Due to the natural colouring material, it can be used as a natural dye on cotton material. The fire retardancy of pomegranate rind extract was tested on jute material under varying alkalinity. Research has indicated that pomegranate rind extract could be used to dye polyamide as well. The rubbing and wash fastness of the finished fabrics is good. The light fastness was fair, and its antibacterial efficiency against tested bacteria was good.

关键词： Natural Polymers Synthetic Polymers Pomegranate Rind Extract (PRE) Dyeing Functional Property

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Condition monitoring of a wind turbine generator using a standalone wind turbine emulator

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Frontiers in Energy 2016年第3期10卷 286-297页

作者： Himani ratna DAHIYA Department of Electrical Engineering National Institute of TechnologyKurukshetra 136119 India

The intend of this paper is to give a description of the realization of a low-cost wind turbine emulator （WTE） with open source technology from graze required for the condition monitoring to diagnose rotor and stator faults in a wind turbine generator （WTG）. The WTE comprises of a 2.5 kW DC motor coupled with a 1 kW squirrel-cage induction machine. This paper provides a detailed overview of the hardware and software used along with the WTE control strategies such as MPPT and pitch control. The emulator reproduces dynamic characteristics both under step variations and arbitrary variation in the wind speed of a typical wind turbine （WT） of a wind energy conversion system （WECS）. The usefulness of the setup has been benchmarked with previously verified WT test rigs made at the University of Manchester and Durham University in UK. Considering the fact that the rotor blades and electric subassemblies direct drive WTs are most susceptible to damage in practice, generator winding faults and rotor unbalance have been introduced and investigated using the terminal voltage and generated current. This wind turbine emulator （WTE） can be reconfigured or analyzed for condition monitoring without the need for real WTs.

关键词： condition monitoring (CM) wind turbine emulator (WTE) wind turbine generator (WTG) maximum power point tracking (MPPT) tip speed ratio (TSR) rotor faults stator faults

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Effective platform for the generation of aerosol droplets and application in evaluating the effectiveness of a MEMS-based nanoparticle trapping device

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Particuology 2009年第6期7卷 471-476页

作者： ratna Tantra Dipak Gohil Peter Cumpson National Physical Laboratory Hampton RoadTeddingtonMiddlesex TW11 0LWUnited Kingdom School of Mechanical and Systems Engineering Newcastle UniversityNewcastle-upon-Tyne NE1 7RUUnited Kingdom

The purpose of this study is two-fold： firstly, the development of a cheap, easy-to-construct and effective nanoparticle generator for testing nanoparticle sensors; secondly, the use of such a generator to test the effectiveness of a sensor device in trapping aerosolised nanoparticles. In this study, we have constructed an effective aerosol generator platform, based on aerosol-assisted chemical vapour deposition technology. Under well-controlled experimental conditions, this platform is capable of depositing aerosolised sodium chloride particles homogeneously on a substrate very effectively. Deposited aerosol droplets were subsequently dried and shown to form nanosized cubic crystals that are free from impurities. This platform was employed to test the effectiveness of a MEMS comb device in the electrostatic trapping of nanoparticles. Upon applying a DC bias （0.5 V） to the MEMS device, results showed an increase in nanoparticle deposition on the surface of the device, due to electrostatic precipitation. The presence of an electric field was shown to affect crystal formation upon drying of the aerosol droplets on the substrate; this caused a blotchy appearance on the SEM image, which was not observed in the absence of electric field.

关键词： Aerosol MEMS sensor Particle generator

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Effect of nanoparticle concentration on zeta-potential measurement results and reproducibility

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Particuology 2010年第3期8卷 279-285页

作者： ratna Tantra Philipp Schulze Paul Quincey National Physical Laboratory Hampton Road Teddington Middlesex TW11 0LW UK Department of Physics University of Bath Bath BA2 7AY UK. National Physical Laboratory Hampton Road Teddington Middlesex TW11 0LW

The effect of nanoparticle concentration on zeta-potential measurement results at dilute concentrations was evaluated. The values of the zeta-potential for four different types of nanoparticles, Ludox （silica）, multi-walled carbon nanotubes （bamboo-shaped and hollow nanotubes） and gold, at various concentrations, were obtained using a laser Doppler electrophoresis instrument. The size of the nanoparticles on dilution was measured using dynamic light scattering （DLS）. The results show that there is a concentration range within which the zeta-potential, and particle size, are not affected by nanoparticle concentration. The lower concentration limit for the system to produce consistent results was dependent on the nature of the sample under study and ranged between 10-2 and 10-4 wt%. Below this concentration, there was an apparent shift in zeta-potential values to less negative values, which was accompanied by an increase in the particle size. The shift in zeta-potential was attributed to an increase in contribution of the signal from extraneous particulate matter. The increase in particle size was attributed to the nature of the homodyne optical configuration of the instrument. The aim of this study was to elucidate the range in nanoparticle concentration that allows for accurate and reliable measurement of the zeta-potential and DLS data.

关键词： Nanoparticles Zeta-potential Dynamic light scattering Reproducibility

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A FEniCS implementation of the phase field method for quasi-static brittle fracture

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Frontiers of Structural and Civil Engineering 2019年第2期13卷 380-396页

作者： HIRSHIKESH Sundararajan NATARAJAN ratna Kumar ANNABATTULA Integrated Modeling and Simulation Lab Department of Mechanical EngineeringIndian Institute of Technology MadrasChennai- 600036India

In the recent years, the phase field method for simulating fracture problems has received considerable attention. This is due to the salient features of the method: 1) it can be incorporated into any conventional finite element software;2) has a scalar damage variable is used to represent the discontinuous surface implicitly and 3) the crack initiation and subsequent propagation and branching are treated with less complexity. Within this framework, the linear momentum equations are coupled with the diffusion type equation, which describes the evolution of the damage variable. The coupled nonlinear system of partial differential equations are solved in a 'staggered? approach. The present work discusses the implementation of the phase field method for brittle fracture within the open-source finite element software, FEniCS. The FEniCS provides a framework for the automated solutions of the partial differential equations. The details of the implementation which forms the core of the analysis are presented. The implementation is validated by solving a few benchmark problems and comparing the results with the open literature.

关键词： phase field method FEniCS brittle fracture crack propagation variational theory of fracture

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Modeling water resources under competing demands for sustainable development: A case study of Kaligandaki Gorge Hydropower Project in Nepal

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Water Science and Engineering 2019年第1期12卷 19-26页

作者： Rakesh Sahukhal Tri ratna Bajracharya Energy Environment Research and Development CentreLalitpur 44602Nepal Institute of Engineering Department of Mechanical EngineeringTribhuwan UniversityLalitpur 44600Nepal

The challenges posed by climate change require that the quantity and quality of water resources in Nepal be managed with sustainable development practices. The communities around the Kaligandaki Gorge Hydropower Project in the Myagdi District of Nepal depend on river flow for most of their rural and agricultural needs. Without a sustainable development plan, the growing population of the region, confined in an area with declining water resources, will face serious challenges to economic growth. Meteorological data show increasing annual average rainfall at a slight rate of about 0.284 mm/year, with erratic annual percentage change in rainfall in the area. The mean and minimum temperatures show decreasing trends at the rates of 0.05-C and 0.14-C per year, respectively. An assessment of the impacts on water availability for domestic and irrigation usage in the face of competing demands caused by the hydropower development project in the Kaligandaki Gorge was undertaken. The water demand and supply modeling were conducted using the water evaluation and planning (WEAP) model, based on discharge data from the Kaligandaki River, which were obtained from the Department of Hydrology and Meteorology, Nepal. The available data from 2001 to 2003 were used to estimate the model parameters while the stability of these parameters was tested with a validation period from 2004 to 2007. The performance of the model was assessed through statistical measures of calibration with the root mean square error and coefficient of determination, whose values were 0.046% and 0.79, respectively. Two scenarios were created in addition to the base case scenario: the discharge decrement scenario and new irrigation technology scenario. Analysis showed that a prioritization of demands will be necessary in the area in the near future for the purpose of sustainability of water resources, due to climate change impacts.

关键词： Climate change Competing demands Sustainable development Hydropower project WEAP

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Gravity-driven powder flow and the influence of external vibration on flow characteristics

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Particuology 2024年第5期88卷 201-209页

作者： Muhammad Shahid Ansari ratna Kumar Annabattula Sathyan Subbiah Department of Mechanical Engineering Indian Institute of Technology MadrasChennai 600036India

The controlled and homogeneous flow of dry granular powders through hoppers is essential for applications,namely,packaging of food grains,fertilizers and additive manufacturing processes such as directed energy deposition for better product *** of the major issues encountered in the granular flows through hoppers is flow stagnation due to the well-known arching ***-assisted granular flow through hoppers is one of the mechanisms used for better mass flow *** this work,the influence of external mechanical vibration on the powder flow is investigated experimentally and using discrete element ***,the mass flow rate through the hopper increases with an increase in vibration amplitude and then decreases,signifying the existence of an optimal amplitude of *** DEM simulations explained the underlying mechanisms for the existence of an optimal amplitude of vibration corresponding to the maximum mass flow rate.A range of vibration amplitudes from 0 mm to 3.5 mm is used to study the flow behaviour;the maximum flow of around 33 g/s to 35 g/s is observed for 0.75 mm to 1.25 mm vibration amplitude for the hopper-particle combination studied in this *** work also reports the influence of vibration frequency,hopper,and particle dimension on the flow *** research facilitates the effective use of mechanical vibration to enhance powder flow that can further be extended to non-spherical and multi-material particles.

关键词： Discrete element method Flow rate Granular flow Path tracking Vibration intensity

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Wormhole Attack Behaviour in Monte-Carlo Localization for Mobile Sensor Networks

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Journal of Sensor Technology 2014年第2期4卷 48-58页

作者： Vennam ratna kumari Aitha Nagaraju Gaurav Pareek Central University of Rajasthan Ajmer India Nigama Engineering College Karimnagar India

Localization is the basic requirement for network management in Wireless Sensor Networks as it helps nodes find their absolute position coordinates and in gathering information relevant to their locations. A localization algorithm has to be dynamic, scalable and should not impose high computation or communication overhead. The localization systems are also prone to attacks. We target a localization scheme for mobile sensor networks called Monte-Carlo Localization, which study its behavior under the most dangerous attack on localization called Wormhole Attack, also known as Collusion Attack and propose a modified algorithm that can help the localization system retain its accuracy level even in the presence of attacks. Our algorithm has communication cost almost equal to that of original localization algorithm (in this case MCL) in the absence of attacks.

关键词： Localization Sensor Networks Collusion Attack

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Cancer therapy using natural ligands that target estrogen receptor beta

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Chinese Journal of Natural Medicines 2015年第11期13卷 801-807页

作者： Gangadhara R Sareddy ratna K.Vadlamudi Department of Obstetrics and Gynecology University of Texas Health Science Center at San Antonio Cancer Therapy & Research Center University of Texas Health Science Center at San Antonio

Estrogen receptor beta(ERβ) is one of the two key receptors(ERα, ERβ) that facilitate biological actions of 17β-estradiol(E2). ERβ is widely expressed in many tissues, and its expression is reduced or lost during progression of many tumors. ERβ facilitates estrogen signaling by both genomic(classical and non-classical) and extra-nuclear signaling. Emerging evidence suggests that ERβ functions as a tissue-specific tumor suppressor with anti-proliferative actions. Recent studies have identified a number of naturally available selective ERβ agonists. Targeting ERβ using its naturally available ligands is an attractive approach for treating and preventing cancers. This review presents the beneficial actions of ERβ signaling and clinical utility of several natural ERβ ligands as potential cancer therapy.

关键词： Estrogen receptor Estrogen receptor beta Tumor suppressor ER beta agonists Liquiritigenin S-equol Genistein

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Developing Mg–Zn surface alloy by friction surface allosying: In vitro degradation studies in simulated body fluids

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International Journal of Minerals,Metallurgy and Materials 2020年第7期27卷 962-969页

作者： Venkateswarlu Badisha Shabana Shaik Ravikumar Dumpala B.ratna Sunil Department of Metallurgical and Materials Engineering Rajiv Gandhi University of Knowledge Technologies(AP-IIIT)Nuzvid 521202India Department of Mechanical Engineering Rajiv Gandhi University of Knowledge Technologies(AP-IIIT)Nuzvid 521202India Department of Mechanical Engineering Visvesvaraya National Institute of TechnologyNagpur 440010India Department of Mechanical Engineering Bapatla Engineering CollegeBapatla 522101India

A new variant of friction-assisted process named friction surface alloying(FSA)for developing surface alloys was demonstrated in the present *** FSA,the dispersed phase is melted and allowed to react with the matrix material to form an alloy at the surface of a metallic *** the present work,magnesium(Mg)sheets and zinc(Zn)powder were selected,and fine grained(~3.5μm)Mg–Zn surface alloy with improved hardness was produced by FSA.X-ray diffraction studies confirmed the formation of intermetallic phases of Mg and Zn at the *** the in vitro degradation studies carried out by immersing in simulated body fluids,a lower corrosion rate was observed for the Mg–Zn surface alloy compared with pure *** surface morphologies after immersion studies indicated large degraded areas on the base Mg compared with Mg–*** results demonstrate the potential of FSA in developing Mg-based surface alloys without melting the substrate to impart better surface properties.

关键词： friction stir processing,surface alloy magnesium zinc corrosion degradation

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