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Artificial intelligence for fault diagnosis of rotating machinery: A review

Wavelets for fault diagnosis of rotary machines: A review with applications

Convolutional Neural Network Based Fault Detection for Rotating Machinery

This review covers advances in electrochemical and biochemical sensor development and usage during 2010 and 2011 In choosing scholarly articles to contribute to this review, special emphasis was placed on work published in the areas of reference electrodes, potentiometric sensors, voltammetric sensors, amperometric sensors, biosensors, immunosensors, and mass sensors In the past two years there have been a number of important papers, that do not fall into the general subsections contained within the larger sections Such novel advances are very important for the field of electrochemical sensors as they open up new avenues and methods for future research Each section above contains a subsection titled “Other Papers of Interest” that includes such articles and describes their importance to the field in general For example, while most electrochemical techniques for sensing analytes of interest are based on the changes in potential or current, Shan et al1 have developed a completely novel method for performing electrochemical measurements In their work, they report a method for imaging local electrochemical current using the optical signal of the electrode surface generated from a surface plasmon resonance (SPR) The electrochemical current image is based on the fact that the current density can be easily calculated from the local SPR signal The authors demonstrated this concept by imaging traces of TNT on a fingerprint on a gold substrate

Full articles and reviews were primarily amassed by searching the SciFinder Scholar and ISI Web of Knowledge Additional articles were found through alternate databases or by perusing analytical journals for pertinent publications Due to the reference limitation, only publications written in English were considered for inclusion Obviously, there have been more published accounts of groundbreaking work with electrochemical and biochemical sensors than those covered here This review is a small sampling of the available literature and not intended to cover every advance of the past two years The literature chosen focuses on new trends in materials, techniques, and clinically relevant applications of novel sensors To ensure proper coverage of these trends, theoretical publications and applications of previously reported sensor development were excluded

We want to remind our readers that this review is not intended to provide comprehensive coverage of electrochemical sensor development, but rather to provide a glimpse of the available depth of knowledge published in the past two years This review is meant to focus on novel methods and materials, with a particular focus on the increasing use of graphene sheets for sensor material development For readers seeking more information on the general principles behind electrochemical sensors and electrochemical methods, we recommend other sources with a broader scope2, 3 Electrochemical sensor research is continually providing new insights into a variety of fields and providing a breadth of relevant literature that is worthy of inclusion in this review Unfortunately, it is impossible to cover each publication and unintentional oversights are inevitable We sincerely apologize to the authors of electrochemical and biochemical sensor publications that were inadvertently overlooked

Electrochemical Sensors and Biosensors

This paper describes mathematical modelling of a freight railway wagon of Indian railways. The freight wagon is modelled as nine-degrees of freedom system. The equations of motion are derived using Newtonian approach. Rail surface vertical profile irregularity of sinusoidal type is taken as input for both the wheels. The frequencies at which these irregularities occur correspond to the natural frequency of the carbody. The equations of motion are solved by MATLAB using a fourth order Runga-Kutta algorithm with a fixed step size. Time domain responses are obtained for different input frequencies and loading conditions while maintaining the wagon speed constant. The effect of variation of the input frequencies of track irregularities and the loading condition on the dynamic behaviour of the carbody is discussed. It has been observed that the empty carbody gets excited to a severe level of acceleration even at lower resonant frequency and a dense region appears near the resonant frequency peak in FFT. The phase trajectories show quasi-periodic nature of response for empty carbody.

Effect of vertical track irregularities on the dynamics of freight railway wagon

The present work describes a theoretical investigation into the effect of surface roughness on the stability margin of an orifice-compensated, hole-entry hybrid journal bearing system. A modified form of the average Reynolds equation is used for the solution of a lubricant flow field in the clearance space of a rough journal bearing system. The effects of surface roughness parameter (A), variance ratio (V rj ), and the surface orientations (y) on the bearing flow, load-carrying capacity, and stability threshold speed margin are studied. The study indicates that the bearing configurations having surface roughness on one of the opposing surfaces (stationary or moving roughness) show an opposite trend between stability threshold speed margin and load-carrying capacity. However, the bearing configurations having transverse- and isotropic-type roughness patterns on both bearing and journal surfaces provide an improved value of both stability threshold speed margin and load-carrying capacity only when the surface roughness has a variance ratio value between 0.49 and 0.59 for the transverse roughness pattern and between 0.59 and 0.84 for the isotropic roughness pattern.

The Stability Margin of a Roughened Hole-Entry Hybrid Journal Bearing System

\nPurpose\nThe porous bearings are commonly used in slider thrust bearings owing to their self-lubricating properties and cost effectiveness as compared to conventional hydrodynamic bearings. The purpose of this paper is to numerically investigate usefulness of porous layer in hydrostatic thrust bearing operating with magnetic fluid. The effect of magnetic field and permeability has been analysed on steady-state (film pressure, film reaction and lubricant flow rate) and rotor-dynamic (stiffness and damping) parameters of bearing.\n\n\nDesign/methodology/approach\nFinite element approach is used to obtain numerical solution of flow governing equations (Magneto-hydrodynamics Reynolds equation, Darcy law and capillary equation) for computing abovementioned performance indices. Finite element method formulation converts elliptical Reynolds equation into set of algebraic equation that are solved using Gauss–Seidel method.\n\n\nFindings\nIt has been reported that porosity has limited but adverse effects on performance parameters of bearing. The adverse effects of porosity can be minimized by using a circular pocket for achieving better steady-state response and an annular/elliptical pocket, for having better rotor-dynamic response. The use of magnetic fluid is found to be substantially enhancing the fluid film reaction (53%) and damping parameters (55%).\n\n\nPractical implications\nThe present work recommends use of circular pocket for achieving better steady-state performance indices. However, annular and elliptical pockets should be preferred, when design criteria for the bearing are better rotor-dynamic performance.\n\n\nOriginality/value\nThis study deals with influence of magnetic fluid, porosity and pocket shape on rotor-dynamic performance of externally pressurized thrust bearing.\n\n\nPeer review\nThe peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2020-0289/\n

Rotor-dynamic performance of porous hydrostatic thrust bearing operating under magnetic field

The present numerical study investigates the combined effect of micro-texture and magneto hydrodynamic lubrication behaviour on the performance of EHL line contact. Micro-textures are provided in the inlet zone of contacting surface has been studied. Modified Reynolds equation, elasticity equation and load balance equation has been solved using FEA and Generalized Minimal Residual Method (GMRES). A parametric study has been performed to optimize the micro-texture shapes in the contacting surfaces for different values of magneto hydrodynamic lubricant parameters The numerical results show that increasing externally applied magnetic field and micro- texture shapes enhances the values of performance parameter of EHL line contact. Finally, the variation in the steady-state EHL characteristics pertaining to unidirectional pure sliding contacts due to an artificially produced IZMTS is investigated numerically. The enhancement in central and minimum film thickness is found to be upto 38% and 28% respectively along with 33.28% reduction in coefficient of friction.

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Influence of MHD Lubrication and Textured Surface in EHL Line Contact

In this paper, a dynamic model with 13 degrees of freedom is developed with the dynamic models of air suspension systems to study the performance of high-speed passenger vehicles’ suspension systems in a deflated state. Sperling's ride index method is used to assess the influence of vibration on ride comfort and quality. This study focuses on the modelling of the air spring with a laminated rubber isolator. Equations for the bounce, pitch, and roll motion of the car's body and bogies have been developed. It has been observed that the shear spring rate of the laminated rubber spring does not depend on the geometry because the shear modulus is not a function of geometry, whereas the compression modulus is strongly affected by the geometry of the design. Therefore, the negative impact due to the vertical irregularities of the track is considered in this study. From the results, it can be concluded that the vehicle should move at a slower speed when the air spring is deflated to maintain passenger comfort. 

Satish C. Sharma

Papers

Effect of vertical track irregularities on the dynamics of freight railway wagon

The Stability Margin of a Roughened Hole-Entry Hybrid Journal Bearing System

Rotor-dynamic performance of porous hydrostatic thrust bearing operating under magnetic field

Influence of MHD Lubrication and Textured Surface in EHL Line Contact

Ride comfort analysis of high-speed rail vehicle using laminated rubber isolator based secondary suspension