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Friction 2021年第6期9卷 1749-1765页

作者： k.e.ch.vidyasagar R.k.PANDeY Dinesh kALYANASUNDARAM Center for Biomedical engineering Indian Institute of Technology DelhiNew Delhi 110016India Department of Biomedical engineering College of EngineeringOsmania UniversityTelangana 500007India Department of Mechanical engineering Indian Institute of Technology DelhiNew Delhi 110016India Department of Biomedical engineering Indian Institute of Technology DelhiNew Delhi 110016India

In case of lightly loaded radial ball bearings,failure mechanisms other than fatigue such as smearing of raceways due to increased frictional torque and vibrations often ***,attempts have been made herein for reducing the frictional torque and minimizing the vibrations of a radial deep groove ball bearing employing surface textures at the inner *** pulsed laser was used to create texture(involving micro-dimples having different dimple area density)on the inner race of test *** an in-house developed test rig,frictional torque and vibrational parameters were measured at different speeds and light loads(*** vicinity of 0.01C,where C is dynamic load capacity of radial ball bearing).Significant reduction in frictional torque and overall vibrations were found in the presence of micro-dimples on inner race at light loads irrespective of operating *** without satisfying the minimum load needed criteria for the satisfactory operation,substantial reduction in smearing marks was found on the races of textured ball bearings in comparison to conventional cases.

关键词： ball bearing textured inner race grease lubricated frictional torque vibration

Improvement of Deep Groove Ball Bearing’s Performance Using a Bionic Textured Inner Race

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Journal of Bionic engineering 2021年第4期18卷 974-990页

作者： k.e.ch.vidyasagar R.k.Pandey Dinesh kalyanasundaram Center for Biomedical engineering Indian Institute of Technology DelhiNew Delhi110016India Department of Biomedical engineering College of EngineeringOsmania UniversityHyderabad500007India Department of Mechanical engineering Indian Institute of Technology DelhiNew Delhi110016India Department of Biomedical engineering All India Institute of Medical SciencesNew Delhi110029India

Micro-textured surfaces have improved the tribological performance of contact surfaces under lubricated conditions;however,not practiced due to manufacturing *** addition to simpler micro-pits or straight-trench type textures,sophisticated bioinspired textures on commercial radial ball bearings have been scarcely *** this work,Dendroaspis polylepis(Mamba snake)skin-type textures were fabricated on the inner race of FAG radial ball bearings using a nanosecond fiber laser *** the snake textures were primarily meant to enhance friction,the dimensions of the texture have been carefully chosen to improve the tribological performance under lubricated *** textured bearings were assembled and experimented at various rotational speeds and lightly loaded conditions to measure vibrational amplitude,frictional torque,and temperature *** to untextured(conventional)bearing,the snake-skin type textured bearings resulted in improved tribo-dynamic performance.

关键词： bionic texture radial ball bearing frictional torque vibration temperature

effect of spark plasma sintering and reinforcements on the formation of ultra-fine and nanograins in AA2024-TiB2-Y hybrid composites

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Progress in Natural Science:Materials International 2022年第1期32卷 79-86页

作者： ch.Suresh vidyasagar D.B.karunakar Department of Architecture and Planning Indian Institute of Technology Roorkee Mechanical and Industrial engineering Department Indian Institute of Technology Roorkee

This study reports the influence of sintering mechanism and reinforcement materials on the formation of ultra-fine and nanograins in Al-TiB-Y nanohybrid composites. The mechanical properties of the composites and their corresponding micro and nanostructures are correlated. The experimental and characterization results revealed that despite the addition of TiB, the hard and brittle AlTi phase formation in the composites was suppressed and hence, their ductility was retained. It was found that yttrium content of 0.3 wt% was the optimum amount which created advantageous spark plasma sintering conditions, and the addition of 0.3 wt% promoted the formation of bi-modal size grains（ultra-fine and nano） along with micro grains, Ω and other nano precipitates, resulting in a significant enhancement in the composite properties. The formation of ultra-fine and nanograins may be attributed to the combined effect of melting and rapid solidification at necking zones due to Joule’s heating and thermomechanical fatigue. Among all the sintered composites, the highest hardness（137 HV）, ultimate tensile strength（UTS）(496 MPa), yield strength（YS）(438 MPa) with 15.7% elongation were obtained in the sintered sample reinforced with 1.0 wt% TiBand 0.3 wt% yttrium.

关键词： Hybrid composites Ultra-fine grains Nano grains Spark plasma sintering Nano precipitates Microstructure

NeCAB family of neuronal calcium-binding proteins in health and disease

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Neural Regeneration Research 2025年第5期20卷 1236-1243页

作者： Diones Bueno Michael k.e.Schafer Sudena Wang Michael J.Schmeisser Axel Methner Institute for Molecular Medicine University Medical Center of the Johannes Gutenberg-UniversityMainzGermany Department of Anesthesiology University Medical Center of the Johannes Gutenberg-UniversityMainzGermany Institute of Anatomy University Medical Center of the Johannes Gutenberg-UniversityMainzGermany

The N-terminal eF-hand calcium-binding proteins 1–3(NeCAB1–3) constitute a family of predominantly neuronal proteins characterized by the presence of at least one eF-hand calcium-binding domain and a functionally less well characterized C-terminal antibiotic biosynthesis monooxygenase domain. All three family members were initially discovered due to their interactions with other proteins. NeCAB1 associates with synaptotagmin-1, a critical neuronal protein involved in membrane trafficking and synaptic vesicle exocytosis. NeCAB2 interacts with predominantly striatal G-protein-coupled receptors, while NeCAB3 partners with amyloid-β A4 precursor protein-binding family A members 2 and 3, key regulators of amyloid-β production. This demonstrates the capacity of the family for interactions with various classes of proteins. NeCAB proteins exhibit distinct subcellular localizations: NeCAB1 is found in the nucleus and cytosol, NeCAB2 resides in endosomes and the plasma membrane, and NeCAB3 is present in the endoplasmic reticulum and Golgi apparatus. The antibiotic biosynthesis monooxygenase domain, an evolutionarily ancient component, is akin to atypical heme oxygenases in prokaryotes but is not wellcharacterized in vertebrates. Prokaryotic antibiotic biosynthesis monooxygenase domains typically form dimers, suggesting that calcium-mediated conformational changes in NeCAB proteins may induce antibiotic biosynthesis monooxygenase domain dimerization, potentially activating some enzymatic properties. However, the substrate for this enzymatic activity remains uncertain. Alternatively, calcium-mediated conformational changes might influence protein interactions or the subcellular localization of NeCAB proteins by controlling the availability of protein–protein interaction domains situated between the eF hands and the antibiotic biosynthesis monooxygenase domain. This review summarizes what is known about genomic organization, tissue expression, intracellular localization, interac

关键词： calcium eF hand mitochondria nervous system signal transduction

Detailed parametric design methodology for hydrodynamics of liquid-solid circulating fluidized bed using design of experiments

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Particuology 2017年第2期15卷 59-68页

作者： Ritesh Ramesh Palkar vidyasagar Shilapuram chemical engineering Department National Institute of Technology Warangal 506004 Telangana India

A design-of-experiments methodology is used to develop a statistical model for the prediction of the hydrodynamics of a liquid–solid circulating fluidized bed. To illustrate the multilevel factorial design approach, a step by step methodology is taken to study the effects of the interactions among the independent factors considered on the performance variables. A multilevel full factorial design with three levels of the two factors and five levels of the third factor has been studied. Various statistical models such as the linear, two-factor interaction, quadratic, and cubic models are tested. The model has been developed to predict responses, viz., average solids holdup and solids circulation rate. The validity of the developed regression model is verified using the analysis of variance. Furthermore, the model developed was compared with an experimental dataset to assess its adequacy and reliability. This detailed statistical design methodology for non-linear systems considered here provides a very important tool for design and optimization in a cost-effective approach

关键词： Hydrodynamics Liquid-solid circulating fluidized bed Statistical design Factorial design approach Response prediction Analysis of variance

effects of yttrium addition and aging on mechanical properties of AA2024 fabricated through multi-step stir casting

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Transactions of Nonferrous Metals Society of china 2020年第2期30卷 288-302页

作者： ch.S.vidyasagar D.B.kARUNAkAR Metallurgical and Materials engineering Department Indian Institute of Technology Roorkee-247667India Mechanical and Industrial engineering Department Indian Institute of Technology Roorkee-247667India

The effects of yttrium and artificial aging on AA2024 alloy were *** developed samples were further subjected to artificial aging at 190℃for 1-10 h with an interval of 1 *** metallurgical characterization was done by scanning electron microscope and X-ray *** mechanical characterization like hardness and tensile strength of the samples was done using computerized Vickers hardness testing machine and universal testing *** microstructures revealed that addition of yttrium refined theα(Al)matrix and led to the formation of Al-Cu-Y intermetallic in the shape of chinese script which strengthened the *** to the base metal,samples with yttrium addition showed better mechanical *** sample reinforced with 0.3 wt.%yttrium showed the highest mechanical properties with the hardness of 66 HV,UTS of 223 MPa,YS of 180 MPa,and elongation of 20.9%.The artificially aged samples showed that the peak hardening of all the samples took place within 5 h of aging at 190℃with Al2 Cu *** changed the intermetallic from chinese script to the fibrous *** optimum amount of yttrium addition to AA2024 was found to be 0.3 wt.%.

关键词： yttrium artificial aging mechanical properties multi-step stir casting precipitation microstructure characterization

characterization of mechanical properties and microstructures of spark plasma sintered and cryo-rolled AA2024−Y composites

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Transactions of Nonferrous Metals Society of china 2020年第6期30卷 1439-1451页

作者： ch.S.vidyasagar D.B.kARUNAkAR Metallurgical and Materials engineering Department Indian Institute of TechnologyRoorkee-247667India Mechanical and Industrial engineering Department Indian Institute of TechnologyRoorkee-247667India

The relationship between the microstructure and mechanical properties of the spark plasma sintered AA2024 Y composites subjected to cryo-rolling was investigated. Yttrium addition enhances the mechanical properties of the composites by promoting grain refinement and precipitation. However, there is a clear trend of initial increase and later decrease in the properties. Also, it is observed that 0.3 wt.% of yttrium is the optimum amount of reinforcement content to obtain the highest mechanical properties. To further improve the tensile strength of the composites, cryo-rolling was performed on the composites under standard cryogenic conditions by several passes up to a reduction of 25%. The mechanical properties and the corresponding microstructures of composites after cryo-rolling were correlated. The SeM and TeM microstructures reveal that the samples exhibit dual size grains, i.e., nanograins are formed as sub-grains within the actual grain. Due to the grain size reduction and the increase in the dislocation density, the tensile properties are remarkably improved compared to those of the composites before cryo-rolling. The highest mechanical properties like hardness, YS and UTS are found to be 153 HV, 539 MPa and 572 MPa, respectively, with a reasonable ductility in the composite with 0.3 wt.% Y.

关键词： secondary processing cryo-rolling nanograins yttrium addition dual size grains spark plasma sintering

Mitigating phytotoxicity of tetracycline by metal-free 8-hydroxyquinoline functionalized carbon nitride photocatalyst

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Journal of environmental Sciences 2023年第3期125卷 37-46页

作者： Toshali Bhoyar Devthade vidyasagar Suresh S.Umare Materials and Catalysis Laboratory Department of ChemistryVisvesvaraya National Institute of Technology(VNIT)Nagpur 440010India School of Material Science and engineering Kyungpook National UniversityDaegu 41566Korea

Photooxidative removal of pharmaceuticals and organic dyes is an effective way to eliminate growing micropollutants. However, photooxidation often results in byproducts as secondary hazardous substances such as phytotoxins. Herein, we found that photooxidation of common antibiotic tetracycline hydrochloride(Tch) over a metal-free 8-hydroxyquinoline(8-HQ) functionalized carbon nitride(CN) photocatalyst significantly reduces the Tch phytotoxic effect. The phytotoxicity test of photocatalytic treated Tch-solution evaluated towards seed growth of Cicer arietinum plant model endowed natural root and shoot *** study highlights the conceptual insights in designing of metal-free photocatalyst for environmental remediation.

关键词： Carbon nitride 8-Hydroxyquinoline Tetracycline hydrochloride Photocatalyst Phytotoxicity Cicer arietinum

enhanced saturation magnetization in La^(3+) doped NiCo ferrites prepared by sol-gel auto-combustion method

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Journal of Rare earths 2024年第8期42卷 1546-1554,I0005页

作者： Maddileti Jelli vidyasagar Thopudurthy krishna Reddy C.V. Department of Physics Rayalaseema UniversityKurnoolA.P518007.Iindia Department of Physics Government PolytechnicRayachotiA.P516269India

Lanthanum doped nickel-cobalt nano ferrites with chemical formula Ni_(0.5)Co_(0.5)LaxFe_(2-x)O_(4)(x=0.05,0,10,0.15 and 0,20) were prepared using a simple sol-gel auto combustion *** basic structural properties were determined by X-ray diffraction method and the formation of single phased spinel ferrite was *** crystalline size decreased from 25 to 11 nm and lattice parameter a increases with increase of La *** surface morphology of these ferrites was observed by field-emission scanning electron microscopy(FeSeM) and agglomerated irregular grains are observed with increase of the rare earth element La ***-dispersive X-ray spectroscopy(eDX) result confirms the presence of the required *** Fourier transform infrared spectroscopy(FTIR) spectrum indicates the formation of the spinel ferrite structure with M-O *** direct band measurements from ultraviolet-visible spectroscopy(UV-Vis) spectroscopy indicate that the direct band gap decreases from 1.39 to 1.19 eV for x=0.05 to x=0.15,then increases to 1.28 eV for x=*** room temperature magnetic properties of these ferrites were studied by a vibrating sample magnetometer(VSM).The enhanced saturation magnetization of 49.73 emu/g is observed for x=0.10 and then saturation magnetizations are gradually decreased for x=0.15 and x=*** the remanent magnetization and coercivity also follow the same trend.

关键词： Ferrites Sol-gel auto combustion La doping Magnetic properties Rare earths

SeQUeNTIAL CONVeX PROGRAMMING MeTHODS FOR SOLVING LARGe TOPOLOGY OPTIMIZATION PROBLeMS： IMPLeMeNTATION AND COMPUTATIONAL ReSULTS

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Journal of Computational Mathematics 2005年第5期23卷 491-502页

作者： Qin Ni ch.Zillober k.Schittkowski Nanjing University of Aeronautics and Astronautics 210016 Nanjing China Department of Computer Science University of BayreuthD-95440 BayreuthGermany

In this paper, we describe a method to solve large-scale structural optimization problems by sequential convex programming （SCP）. A predictor-corrector interior point method is applied to solve the strictly convex subproblems. The SCP algorithm and the topology optimization approach are introduced. especially, different strategies to solve certain linear systems of equations are analyzed. Numerical results are presented to show the efficiency of the proposed method for solving topology optimization problems and to compare different variants.

关键词： Large scale optimization Topology optimization Sequential convex programming method Predictor-corrector interior point method Method of moving asymptotes