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  • 1
    Online Resource
    Online Resource
    Performance of hybrid thrust bearing textured surface operating with electro-rheological lubricant
    SAGE Publications ; 2023
    In:  Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology Vol. 237, No. 4 ( 2023-04), p. 911-925
    Details
    In: Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, SAGE Publications, Vol. 237, No. 4 ( 2023-04), p. 911-925
    Abstract: This article concerns with the numerical simulations of textured surface hybrid thrust bearings operating with Electro-rheological (ER) lubricant. An ER fluid comprises dielectric particles suspended in an insulating viscous medium. Electrorheological (ER) lubricants are considered smart lubricants. Reynold's equation is used to model the flow of an ER lubricant in textured surface thrust bearings. The texture is provided as hemispherical, cylindrical, elliptical, and square shape micro-depression oriented along the circumferential and radial direction. The Patir and Cheng model is used to describe micro-roughness on a thrust pad. The continuous Bingham model is used to define the viscosity of the ER lubricant in terms of yielding stress, electric field, and shear-strain rate. The Reynolds equation is solved by applying the finite element method to obtain film pressure, load-supporting capacity, frictional power loss, film stiffness, and damping parameters. The texture shapes are optimized for dimple size, depth, and length for getting maximum load-supporting capacity and stiffness coefficient, and minimum frictional power loss. The numerical results predicted an enhancement in the load-supporting capacity (+257.3%) and film stiffness parameters (+323.2%) owing to the synergistic use of ER lubricant and optimized geometric parameters of square/elliptical dimples. The frictional power loss was reported to reduce significantly (−48.8%) by the use of micro-dimples. The application of ER lubricant was also found to slightly enhance (+4.3%) the frictional power loss in textured bearings. The transverse surface roughness vis-à-vis smooth surface is observed to improve the load-supporting capacity, stiffness, and damping parameters of textured surface bearings.
    Type of Medium: Online Resource
    ISSN: 1350-6501 , 2041-305X
    URL: Article
    DOI: 10.1177/13506501221128110
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2023
    detail.hit.zdb_id: 2032767-5
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  • 2
    Online Resource
    Online Resource
    Influence of geometric imperfection of journal on the performance of porous hybrid journal bearing under turbulent condition
    SAGE Publications ; 2021
    In:  Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology Vol. 235, No. 9 ( 2021-09), p. 1879-1896
    Details
    In: Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, SAGE Publications, Vol. 235, No. 9 ( 2021-09), p. 1879-1896
    Abstract: The present work deals with numerical investigation into geometric imperfection (bellmouth, undulation and barrel shape) of the journal on performance of a porous hybrid journal bearing system (PHJBs) operating under turbulent flow condition. The Reynolds equation governing the flow of lubricant in the bearing clearance space is modified by using the turbulent lubrication theory proposed by Constantinescu’s. The bearing performance parameters are numerically computed using FEM. The effects of geometric irregularities, turbulent flow condition, and permeability parameters have been investigated on the performance of PHJBs. The theoretically obtained results indicates that the combined effect of turbulent flow condition and geometric imperfection offers enhanced values of [Formula: see text] and rotor dynamic coefficients (stiffness and damping coefficients).
    Type of Medium: Online Resource
    ISSN: 1350-6501 , 2041-305X
    URL: Article
    DOI: 10.1177/1350650120976427
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2021
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  • 3
    Online Resource
    Online Resource
    Influence of Percolation effect of additives on the Performance of Conical Textured Porous Hybrid Journal Bearing
    SAGE Publications ; 2022
    In:  Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology Vol. 236, No. 12 ( 2022-12), p. 2406-2438
    Details
    In: Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, SAGE Publications, Vol. 236, No. 12 ( 2022-12), p. 2406-2438
    Abstract: Textured bearing surfaces are widely used to reduce the friction in lubricated contacts. Besides the hydrodynamic pressure generated by the physical wedge, micro-textures act as micro-bearings and generates localized pressure. As a result, an additional load carrying capacity is generated. Further, micro-texture also serves as a lubricant reservoir, trapping wear debris and abrasive particles to improve the performance of tribo- pair. In this study, the effect of micro-textures and percolation effect of additives on the performance of hybrid conical porous journal bearings (HCPJB S ) has been studied. The interactive effects of permeability parameter, spherical shaped micro-texture, semi cone angle and couple stress lubricant parameter considering the percolation effect parameter of additives on the performance of HCPJB S has been studied. FEM is used to numerically simulate the flow behaviour of couple stress lubricant in the bearing clearance space of a HCPJB S . The results shows that the HCPJB S operating with couple stress lubricant provides enhanced stability margin [Formula: see text] for lower values of permeability parameter [Formula: see text] and semi cone angle [Formula: see text].
    Type of Medium: Online Resource
    ISSN: 1350-6501 , 2041-305X
    URL: Article
    DOI: 10.1177/13506501221082744
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2022
    detail.hit.zdb_id: 2032767-5
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  • 4
    Online Resource
    Online Resource
    Performance of rough surface hydrodynamic circular and multi-lobe journal bearings in turbulent regimes
    SAGE Publications ; 2023
    In:  Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology Vol. 237, No. 4 ( 2023-04), p. 860-880
    Details
    In: Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, SAGE Publications, Vol. 237, No. 4 ( 2023-04), p. 860-880
    Abstract: This article deals with the steady and dynamic performance analysis of rough surface circular and multi-lobe journal bearings operating with non-Newtonian lubricant in turbulent regimes. The numerical solution of Reynold's equation was obtained using the finite element method. To account for surface roughness, the Patir and Cheng model was used, and fluid turbulent behavior was modeled using the turbulent theory as proposed by Ng and Pan. The non-Newtonian behavior of the lubricant is presented by the Rabinowitsch fluid model, and JFO boundary conditions are used to solve Reynold's equation, considering gaseous cavitation. The bearing with micro-roughness has been considered in numerical analysis and transverse roughness has been reported to improve bearing performance indices. Among the different bearing design configurations, the two-lobe bearing configuration provides significantly improves the minimum film thickness, hydrodynamic pressure, and dynamic parameters. The presence of turbulent flow and transverse surface roughness produces a synergistic effect that enhances the minimum film thickness, stiffness, and damping parameters of journal bearings. This study provides a detailed comparison between various bearing designs and recommends the use of two-lobe bearings for high-speed applications.
    Type of Medium: Online Resource
    ISSN: 1350-6501 , 2041-305X
    URL: Article
    DOI: 10.1177/13506501221117956
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2023
    detail.hit.zdb_id: 2032767-5
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  • 5
    Online Resource
    Online Resource
    The National Mental Health Survey of India (2016): Prevalence, socio-demographic correlates and treatment gap of mental morbidity
    SAGE Publications ; 2020
    In:  International Journal of Social Psychiatry Vol. 66, No. 4 ( 2020-06), p. 361-372
    Details
    In: International Journal of Social Psychiatry, SAGE Publications, Vol. 66, No. 4 ( 2020-06), p. 361-372
    Abstract: Recognizing the need for good quality, scientific and reliable information for strengthening mental health policies and programmes, the National Mental Health Survey (NMHS) of India was implemented by National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, in the year 2015–2016. Aim: To estimate the prevalence, socio-demographic correlates and treatment gap of mental morbidity in a representative population of India. Methods: NMHS was conducted across 12 Indian states where trained field investigators completed 34,802 interviews using tablet-assisted personal interviews. Eligible study subjects (18+ years) in households were selected by a multi-stage, stratified, random cluster sampling technique. Mental morbidity was assessed using MINI 6. Three-tier data monitoring system was adopted for quality assurance. Weighted and specific prevalence estimates were derived (current and lifetime) for different mental disorders. Mental morbidity was defined as those disorders as per the International Statistical Classification of Diseases, Tenth Revision Diagnostic Criteria for Research (ICD-10 DCR). Multivariate logistic regression was conducted to examine risk for mental morbidity by different socio-demographic factors. Survey was approved by central and state-level institutional ethical committees. Results: The weighted lifetime prevalence of ‘any mental morbidity’ was estimated at 13.67% (95% confidence interval (CI) = 13.61, 13.73) and current prevalence was 10.56% (95% CI = 10.51, 10.61). Mental and behavioural problems due to psychoactive substance use (F10–F19; 22.44%), mood disorders (F30–F39; 5.61%) and neurotic and stress-related disorders (F40–F48; 3.70%) were the most commonly prevalent mental morbidity in India. The overall prevalence was estimated to be higher among males, middle-aged individuals, in urban-metros, among less educated and in households with lower income. Treatment gap for overall mental morbidity was 84.5%. Conclusion: NMHS is the largest reported survey of mental morbidity in India. Survey estimated that nearly 150 million individuals suffer from one or the other mental morbidity in India. This information is to be used for planning, delivery and evaluating mental health programming in the country.
    Type of Medium: Online Resource
    ISSN: 0020-7640 , 1741-2854
    URL: Article
    DOI: 10.1177/0020764020907941
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2020
    detail.hit.zdb_id: 2066492-8
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