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Selective recovery of rare earth elements by smelting of magnets

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Journal of Rare Earths 2025年第1期43卷 209-217,I0008页

作者： Venkata Lakshmi Borra Prasanta Jana PPSahoo Prakash venkatesan Mehmet Ali Recai Onal Chenna Rao Borra Department of Metallurgical and Materials Engineering Indian Institute of Technology KharagpurWest Bengal721302India R&D Tata Steel Ltd.Jamshedpur831001India Department of Materials Engineering Synthesis and Recycling(4MAT)Universite Libre de BruxellesCP165/631050BrusselsBelgium GenoMines 630 Rue Noetzlin91190ParisFrance

Rare earth elements(REEs)play a crucial role in many technologies from daily appliances in cell phones to more advanced wind turbines and electric *** magnets account for a quarter of total global REEs production and have high recycling *** this study,smelting process was used to selectively oxidize REEs in the permanent magnets by adding Fe_(2)O_(3).This separates REEs into a slag phase from an iron-rich metallic phase.B_(2)O_(3) was also added to the system as a flux to lower the slag melting *** minimizes REEs loss to the metallic phase and allows a more efficient phase *** effect of flux and oxidizing agent addition was investigated on both regular and cerium-rich NdFeB(NdCeFeB)*** 1350℃and for 1 h,the slag phase was successfully separated from the metallic phase with the addition of 0.8 stoichiometric amount of Fe_(2)O_(3) and 40 wt%of B_(2)O_(3).Scanning electron microscopy-energy dispersive X-ray spectroscopy(SEM-EDX)analysis reveals that REEs in the magnet do not migrate to the metal phase while the REE-rich slag phase contains almost no *** the selective removal of iron into the metallic phase,REEs are recovered from the slag phase through an acid leaching process allowing>99%of REEs *** in the magnet can also be recovered as useful boric acid by evaporation and crystallisation *** proposed process in this study is reagent and energy-efficient with almost complete valorisation of both NdCeFeB and NdFeB magnets.

关键词： Recycling Rare earth elements NdFeBmagnets Smelting Leaching

Mind the gut:Navigating the complex landscape of gastroprotection in neurosurgical patients

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World Journal of Gastroenterology 2025年第8期31卷 1-8页

作者： Subeikshanan venkatesan Brandon Lucke-Wold Department of Neurosurgery University of FlordiaGainesvilleFL 32608United States

Neurosurgical patients,including those with severe traumatic brain injury,spinal cord injury,stroke,or raised intracranial pressure,are at heightened risk for stress ulcers and aspiration pneumonitis,leading to significant morbidity and *** patients are typically managed through both pharmacological interventions[e.g.,proton pump inhibitors(PPIs),histamine 2(H2)antagonists,sucralfate]and non-pharmacological measures(e.g.,nasogastric decompression,patient positioning)to mitigate adverse *** pathogenesis of stress ulcers in neurosurgical patients is multifactorial,but the routine use of stress ulcer prophylaxis remains *** gastric acid suppression with H2 rece-ptor antagonists and PPIs is commonly employed,concerns have arisen regarding the association between elevated gastric pH,bacterial colonization,and ventilator-associated *** lack of comprehensive data on gastroprotection in critically ill neurosurgical patients,who face a greater risk than non-neurosurgical counterparts,further complicates this *** studies,such as one by Gao et al on the efficacy of vonoprazan-amoxicillin dual therapy in elderly patients,highlight the potential of novel therapies,but the influence of pre-existing conditions like Helicobacter pylori infection remains ***-pharmacological interventions,including nasogastric decompression and early enteral nutrition,are critical in improving outcomes but require further research to refine *** editorial underscores the need for tailored approaches and encourages further investigation into optimal gastroprotective strategies for neurosurgical patients.

关键词： Gastroprotection Neurosurgery Stress ulcer Proton pump inhibitor Histamine 2 receptor antagonist Vonoprazan Nasogastric tube Enteral nutrition

Lagrangian Coherent Structures in Tandem Flapping Wing Hovering

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Journal of Bionic Engineering 2017年第2期14卷 307-316页

作者： srinidhi Nagarada Gadde Sankaranarayanan Vengadesan Department of Applied Mechanics Indian Institute of Technology Madras Chennai Tamil Nadu India

Lagrangian Coherent Structures （LCS） of tandem wings hovering in an inclined stroke plane is studied using Immersed- Boundary Method （IBM） by solving two dimensional （2D） incompressible Navier-Stokes equations. Coherent structures re- sponsible for the force variation are visualized by calculating Finite Time Lyapunov Exponents （FTLE）, and vorticity contours. LCS is effective in determining the vortex boundaries, flow separation, and the wing-vortex interactions accurately. The effects of inter-wing distance and phase difference on the force generation are studied. Results show that in-phase stroking generates maximum vertical force and counter-stroking generates the least vertical force. In-phase stroking generates a wake with swirl, and counter stroking generates a wake with predominant vertical velocity. Counter stroking aids the stability of the body in hovering. As the hindwing operates in the wake of the forewing, due to the reduction in the effective Angle of Attack （AoA）, the hindwing generates lesser force than that of a single flapping wing.

关键词： dragonfly tandem wings LCS IBM

An essay on conceptualization of issues in empirical accounting research

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China Journal of Accounting Research 2013年第3期6卷 149-166页

作者： Bin srinidhi Department of Accounting University of Texas at ArlingtonUnited States

Empirical research in accounting has lately focused much on sophisticated statistical methodology and econometrics and relatively less on conceptualization of the issues concerned. This essay is written to highlight the conceptualization of the issues as an important ingredient of empirical research in accounting. I present two methods of conceptualization – the single-entity approach and the game theoretic approach. I give several examples in accounting research to explain the conceptualization process. I hope that this essay will fill a much needed void in the research process in accounting and restore the balance between conceptualization and methodology.

关键词： Conceptualization Maintained hypothesis Single-entity approach Game theory approach

Valorization of agro-industrial fruit peel waste to fluorescent nanocarbon sensor:Ultrasensitive detection of potentially hazardous tropane alkaloid

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Frontiers of Environmental Science & Engineering 2022年第3期16卷 1-11页

作者： Athiyanam venkatesan Ramya Manoj Balachandran Nanocarbon Research Group Materials Science Research LaboratoryDepartment of Physics and ElectronicsCHRIST(Deemed to be University)Bengaluru-560029KarnatakaIndia

Millions of tonnes of agro-industrial waste are generated each year globally,with the vast majority of it going untreated,underutilized,and disposed of by burning or landfilling,causing severe environmental distress and economic downturn.A practical solution to this global issue is to use green chemistry to convert this waste into value-added ***,in the present study,agro-industrial orange peel waste was valorized into fluorescent nanodiamond-like carbon sensor via a green route involving hydrothermal treatment of microwave carbonized orange peel *** developed sensor,used for the fluorescence detection of potentially hazardous drug atropine sulfate,exhibits unique dual linearity over concentration ranges of 300 nM to 1 M and from 1 M to 10 M,as well as ultra-low sensitivity of 34.42 nM and 356.46 nM,***,the sensor demonstrates excellent reproducibility,high stability,and satisfactory recovery when used to identify and quantify atropine sulfate in biological samples and commercially available pharmaceuticals,indicating promising multidisciplinary applications.

关键词： Agro-industrial waste Orange peel Valorization Nanodiamond-like carbon Atropine sulphate Fluorescence sensing

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Characterization and optimization of pulse electrodeposition of Ni/nano-Al_2O_3 composite coatings

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International Journal of Minerals,Metallurgy and Materials 2013年第5期20卷 479-485页

作者： A.Jegan R.venkatesan Department of Mechanical Engineering Sona College of Technology

Nickel/nano-A1203 composite coatings produced by the pulse electrodeposition method and the influence of pulse parameters, i.e., pulse frequency, duty cycle, and current density on the microstructure, hardness, and corrosion resistance, were critically investigated on an AISI 1018 mild steel specimen electroplated in a Watt＇s type bath. The experiments were carried out with different combinations of pulse parameters using Taguchi＇s L27 orthogonal array, and 27 trials were conducted to study the effect of pulse parameters in view to maximize the hardness of the specimen. The assessment results clearly reveal that the specimen exhibits the maximum hardness at the pulse frequency of 20 Hz, duty cycle of 30%, and peak current density of 0.4 A/cm2, which are designated as the optimal parameters herein. Furthermore, the influences of those optimized pulse parameters over the microstructure and corrosion resistance were investigated, and some conclusions were drawn. Also, from the ANOVA examination, it is clear that duty cycle is predominant in affecting the hardness, while current density has relatively low impact.

关键词： composite coatings nickel alumina nanoparticles electrodeposition corrosion resistance hardness

A review on front end conversion in ocean wave energy converters

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Frontiers in Energy 2015年第3期9卷 297-310页

作者： Nagulan SANTHOSH venkatesan BASKARAN Arunachalam AMARKARTHIK Department of Mechanical Engineering Bannari Amman Institute of Technology Sathyamangalam 638401 India

Harvesting the energy from ocean waves is one of the greatest attractions for energy engineers and scientists. Till date, plenty of methods have been adopted to harvest the energy from the ocean waves. However, due to technological and economical complexity, it is intricate to involve the majority of these energy harvesters in the real ocean environment. Effective utilization and sustain- ability of any wave energy harvester depend upon its adaptability in the irregular seasonal waves, situation capability in maximum energy extraction and finally fulfilling the economic barriers. In this paper, the front end energy conversions are reviewed in detail which is positioned in the first stage of the wave energy converter among other stages such as power take off （PTO） and electrical energy conversion. If the recent development of these front end energy conversion is well known then developing wave energy converter with economic and commercial viability is possible. The aim of this review is to provide information on front end energy conversion of a point absorber and emphasize the strategies and calamity to be considered in designing such kinds of devices to improve the energy harvesting competence. This will be useful to the engineers for speeding up the development of a matured point absorbing type wave energy converter.

关键词： wave energy converter point absorbers,power take off (PTO) front end energy conversion

Chemical composition and anti-inflammatory activity of Boswellia ovalifoliolata essential oils from leaf and bark

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Journal of Forestry Research 2018年第2期29卷 370-378页

作者： venkatesan Geetha Sarada Nallani Chakravarthula Department of Chemistry School of Advanced SciencesVIT University

We isolated the essential oils from Boswellia ovalifoliolata *** and *** using hydrodistillation,identified the obtained compounds using gas chromatography–mass spectrometry(GC–MS) and Fourier transform-infrared spectroscopy(FT-IR),and studied the photophysical and electrochemical properties using UV–visible and fluorescence spectroscopy and cyclic *** the basis of GC–MS spectra,38 compounds were identified in the essential oil from leaves and 26 in the oil from *** bark oil contained 13.44% b-Farnesene(sesquiterpene),10.45% caryophyllene oxide(sesquiterpene) and 6.6% spathulenol,(2 Z,6 E)-(sesquiterpene alcohol); the leaf oil contained 11.1% spathulenol(sesquiterpene alcohol),9.0% caryophyllene oxide(sesquiterpenoids) and 6.3% decyl acetate(ester).FT-IR spectra confirmed the presence of aliphatic aldehydes and ketones,carboxylic acid,alcohols,esters and ethers in both oil ***–visible absorption spectra showed maximum absorbance at 245,290 and 402 nm for bark oil,and 250,285 and 325 nm for *** oil showed strong emission with maximum emission wavelength at 456 nm was higher than that of leaf oil at 414 *** essential oil had significant anti-inflammatory activity,and the reduction potential of the leaf oil was-0.44 and-0.56 e V for bark.

关键词： Essential oil Boswellia ovalifoliolata Gas chromatography–mass spectrometry Fourier transforminfrared spectroscopy Cyclic voltammetry fluorescence spectroscopy

Single-phase Thirteen-level Dual-boost Inverter Based Shunt Active Power Filter Control Using Resonant and Fuzzy Logic Controllers

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CSEE Journal of Power and Energy Systems 2022年第3期8卷 849-863页

作者： Shaik Gouse Basha venkatesan Mani Subbarao Mopidevi Vignan's Foundation for Science Technology and Research Andhra Pradesh522213India Vignan's Lara Institute of Technology and Science Vadlamudi522213India

This paper addresses the power quality improvement of a single-phase utility grid using a thirteen-level dualboost inverter(TLDBI)-shunt active filter(SAF).The TLDBI uses a single DC source of low voltage magnitude and five switched capacitor arrangement to achieve self-balanced thirteen level output ***,the charging and voltage balancing of the capacitor is achieved by proper switching sequence control in a series,through which boosted inverter output voltage levels are *** with the tradional H-bridge multilevel inverters(MLIs),all the elements in the proposed TLDBI are able to withstand a voltage stress which is equal to the input DC *** feature ensures the performance of the proposed TLDBI in high-frequency *** power at the electrical grid is highly affected by a wide range of non-linear *** proposed SAF is used for measuring and controlling the current flow from source to *** difference between the targeted and actual currents from the utility grid is measured by using the modified synchronous reference frame(SRF)*** estimated error current is used by the controllers to predict the optimum suitable switching angle and modulation index(MI)to the *** this paper,the traditional proportional-integral(PI)controller,fuzzy logic controller(FLC)and proportional resonant controller(PRC)are compared and the results are presented to validate the performance of *** stability and robustness of the proposed controller is evaluated using Bode,Root locus,and Nyquist *** modeling and analysis of the proposed system are done using MATLAB/Simulink *** simulation results are presented in the various MI of TLDBI and also subjected to non-linear load *** results are also compared to the claim novelty of the proposed study.

关键词： FLC power quality PRC thirteen-level DBI shunt active filter single-phase utility grid SRF