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Satish C. Sharma - One of the best experts on this subject based on the ideXlab platform.

  • combined influence of couple stress lubricant Recess geometry and method of compensation on the performance of hydrostatic circular thrust pad bearing
    Proceedings of the Institution of Mechanical Engineers Part J: Journal of Engineering Tribology, 2017
    Co-Authors: Vivek Kumar, Satish C. Sharma
    Abstract:

    This study concerns with the theoretical investigation to show the influence of Recess geometry and method of compensation on the performance of Recessed hydrostatic circular thrust pad bearing operating with couple stress lubricant. Modified Reynolds equation for couple stress lubricant has been derived using Stokes microcontinuum theory. Stokes theory describes the behavior of fluids consisting of long chain polymer additives having sizes comparable to that of the fluid film thickness. Finite element method technique and commercially available software MATLAB 2013 have been used to solve the modified Reynolds equation and, thus, performance characteristics of bearing have been computed. The performance of capillary- and orifice-compensated hydrostatic thrust pad bearings performance have been compared vis-a-vis to different geometric shapes of Recess. Each Recess shape has identical ratio of bearing pad area to Recess area. It has been observed that the couple stress additives have significant positive ...

  • orifice compensated multiRecess hydrostatic hybrid journal bearing system of various geometric shapes of Recess operating with micropolar lubricant
    Tribology International, 2011
    Co-Authors: Rajasekhar E Nicodemus, Satish C. Sharma
    Abstract:

    Abstract The objective of the present paper is to study analytically the performance of four-pocket orifice compensated hydrostatic/hybrid journal bearing system of various geometric shapes of Recess operating with micropolar lubricant. The modified Reynolds equation for micropolar lubricant is solved using FEM and the Newton–Raphson method along with appropriate boundary conditions. The results suggest that the influence of micropolar effect of lubricant on bearing performance is predominantly affected by the geometric shape of Recess and restrictor design parameter. Therefore, the bearing designer must judiciously choose an appropriate geometric shape of Recess in order to get an overall enhanced bearing performance.

  • performance of membrane compensated multiRecess hydrostatic hybrid flexible journal bearing system considering various Recess shapes
    Tribology International, 2004
    Co-Authors: Narendra Singh, Satish C. Sharma, S C Jain, Sanjeeva S Reddy
    Abstract:

    The paper describes a theoretical study concerning the performance of an externally pressurized multiRecess hydrostatic/hybrid flexible journal bearing system by varying the geometric shape of Recess and using the membrane flow valve restrictor as a compensating element. The four different Recess geometries of the bearing studied in the present study are a square Recessed bearing, a circular Recessed bearing, an elliptical Recessed bearing and a triangular Recessed bearing. The equation governing the flow of lubricant in a journal bearing together with 3D elasticity equation and restrictor flow equation are solved by using the Finite Element Method. The study describes the effect of Recess shape, bearing flexibility and a method of compensation on the performance characteristics of a hydrostatic/hybrid journal bearing system. A comparative performance of the membrane compensated hydrostatic/hybrid journal bearing system has also been studied vis-a-vis capillary, orifice and constant flow valve restrictors. The results presented in this study amply demonstrate that the shape of Recess/pocket of a hydrostatic/hybrid flexible journal bearing system affects the performance of the bearing quite appreciably and a proper selection of Recess shape along with a suitable compensating device is needed to get an improved performance from the bearing.

  • performance of hydrostatic hybrid journal bearings with unconventional Recess geometries
    Tribology Transactions, 1998
    Co-Authors: Satish C. Sharma, S C Jain, Narendra Singh, R Sinhasan, Shant K Singh
    Abstract:

    A theoretical study using FEM is performed of multiRecess capillary compensated hydrostatic/hybrid journal bearings which find use in number of engineering applications. In this study, bearings having four different Recess shapes were observed for their static and dynamic performance parameters which include minimum film thickness, flow rate, rotordynamic coefficients and threshold speed. The bearings with four different Recess geometries included in the present study were a square Recess bearing, a circular Recess bearing a triangular Recess bearing and an elliptical Recess bearing. Comparisons of performance characteristics were made to determine which Recess shape gives the best performance. The results presented in this paper are expected to help machine tool designers make better use of the Recess shapes. Presented at the 52nd Annual Meeting In Kansas City, Missouri May 10–22, 1997

Patricia A Hudgins - One of the best experts on this subject based on the ideXlab platform.

  • failed endoscopic sinus surgery spectrum of ct findings in the frontal Recess
    Radiographics, 2009
    Co-Authors: Benjamin Y Huang, Kristen M Lloyd, John M Delgaudio, Eric Jablonowski, Patricia A Hudgins
    Abstract:

    Since its introduction over 2 decades ago, functional endoscopic sinus surgery (FESS) has revolutionized the surgical management of chronic sinusitis. Performed over 200,000 times annually in the United States to treat medically refractory sinusitis, FESS has success rates as high as 98%. When surgical failure occurs, it is typically due to postoperative scarring or unaddressed outflow tract obstruction in the region of the frontal Recess. The most common causes of surgical failure in the frontal Recess include remnant frontal Recess cells, a retained uncinate process, middle turbinate lateralization, osteoneogenesis, scarring or inflammatory mucosal thickening, and recurrent polyposis. Computed tomography (CT) of the paranasal sinuses has become indispensable in evaluation of patients with FESS failure, particularly in the frontal Recess, a location that can be difficult to visualize at endoscopy. Familiarity with the complex anatomy of the frontal Recess and knowledge of the most common causes of surgical failure are essential for proper interpretation of sinus CT images obtained in patients being considered for revision FESS of the frontal sinus.

  • failed endoscopic sinus surgery spectrum of ct findings in the frontal Recess
    Radiographics, 2009
    Co-Authors: Benjamin Y Huang, Kristen M Lloyd, John M Delgaudio, Eric Jablonowski, Patricia A Hudgins
    Abstract:

    Since its introduction over 2 decades ago, functional endoscopic sinus surgery (FESS) has revolutionized the surgical management of chronic sinusitis. Performed over 200,000 times annually in the United States to treat medically refractory sinusitis, FESS has success rates as high as 98%. When surgical failure occurs, it is typically due to postoperative scarring or unaddressed outflow tract obstruction in the region of the frontal Recess. The most common causes of surgical failure in the frontal Recess include remnant frontal Recess cells, a retained uncinate process, middle turbinate lateralization, osteoneogenesis, scarring or inflammatory mucosal thickening, and recurrent polyposis. Computed tomography (CT) of the paranasal sinuses has become indispensable in evaluation of patients with FESS failure, particularly in the frontal Recess, a location that can be difficult to visualize at endoscopy. Familiarity with the complex anatomy of the frontal Recess and knowledge of the most common causes of surgical failure are essential for proper interpretation of sinus CT images obtained in patients being considered for revision FESS of the frontal sinus.

Benjamin Y Huang - One of the best experts on this subject based on the ideXlab platform.

  • failed endoscopic sinus surgery spectrum of ct findings in the frontal Recess
    Radiographics, 2009
    Co-Authors: Benjamin Y Huang, Kristen M Lloyd, John M Delgaudio, Eric Jablonowski, Patricia A Hudgins
    Abstract:

    Since its introduction over 2 decades ago, functional endoscopic sinus surgery (FESS) has revolutionized the surgical management of chronic sinusitis. Performed over 200,000 times annually in the United States to treat medically refractory sinusitis, FESS has success rates as high as 98%. When surgical failure occurs, it is typically due to postoperative scarring or unaddressed outflow tract obstruction in the region of the frontal Recess. The most common causes of surgical failure in the frontal Recess include remnant frontal Recess cells, a retained uncinate process, middle turbinate lateralization, osteoneogenesis, scarring or inflammatory mucosal thickening, and recurrent polyposis. Computed tomography (CT) of the paranasal sinuses has become indispensable in evaluation of patients with FESS failure, particularly in the frontal Recess, a location that can be difficult to visualize at endoscopy. Familiarity with the complex anatomy of the frontal Recess and knowledge of the most common causes of surgical failure are essential for proper interpretation of sinus CT images obtained in patients being considered for revision FESS of the frontal sinus.

  • failed endoscopic sinus surgery spectrum of ct findings in the frontal Recess
    Radiographics, 2009
    Co-Authors: Benjamin Y Huang, Kristen M Lloyd, John M Delgaudio, Eric Jablonowski, Patricia A Hudgins
    Abstract:

    Since its introduction over 2 decades ago, functional endoscopic sinus surgery (FESS) has revolutionized the surgical management of chronic sinusitis. Performed over 200,000 times annually in the United States to treat medically refractory sinusitis, FESS has success rates as high as 98%. When surgical failure occurs, it is typically due to postoperative scarring or unaddressed outflow tract obstruction in the region of the frontal Recess. The most common causes of surgical failure in the frontal Recess include remnant frontal Recess cells, a retained uncinate process, middle turbinate lateralization, osteoneogenesis, scarring or inflammatory mucosal thickening, and recurrent polyposis. Computed tomography (CT) of the paranasal sinuses has become indispensable in evaluation of patients with FESS failure, particularly in the frontal Recess, a location that can be difficult to visualize at endoscopy. Familiarity with the complex anatomy of the frontal Recess and knowledge of the most common causes of surgical failure are essential for proper interpretation of sinus CT images obtained in patients being considered for revision FESS of the frontal sinus.

Sanjeeva S Reddy - One of the best experts on this subject based on the ideXlab platform.

  • performance of membrane compensated multiRecess hydrostatic hybrid flexible journal bearing system considering various Recess shapes
    Tribology International, 2004
    Co-Authors: Narendra Singh, Satish C. Sharma, S C Jain, Sanjeeva S Reddy
    Abstract:

    The paper describes a theoretical study concerning the performance of an externally pressurized multiRecess hydrostatic/hybrid flexible journal bearing system by varying the geometric shape of Recess and using the membrane flow valve restrictor as a compensating element. The four different Recess geometries of the bearing studied in the present study are a square Recessed bearing, a circular Recessed bearing, an elliptical Recessed bearing and a triangular Recessed bearing. The equation governing the flow of lubricant in a journal bearing together with 3D elasticity equation and restrictor flow equation are solved by using the Finite Element Method. The study describes the effect of Recess shape, bearing flexibility and a method of compensation on the performance characteristics of a hydrostatic/hybrid journal bearing system. A comparative performance of the membrane compensated hydrostatic/hybrid journal bearing system has also been studied vis-a-vis capillary, orifice and constant flow valve restrictors. The results presented in this study amply demonstrate that the shape of Recess/pocket of a hydrostatic/hybrid flexible journal bearing system affects the performance of the bearing quite appreciably and a proper selection of Recess shape along with a suitable compensating device is needed to get an improved performance from the bearing.

Narendra Singh - One of the best experts on this subject based on the ideXlab platform.

  • performance of membrane compensated multiRecess hydrostatic hybrid flexible journal bearing system considering various Recess shapes
    Tribology International, 2004
    Co-Authors: Narendra Singh, Satish C. Sharma, S C Jain, Sanjeeva S Reddy
    Abstract:

    The paper describes a theoretical study concerning the performance of an externally pressurized multiRecess hydrostatic/hybrid flexible journal bearing system by varying the geometric shape of Recess and using the membrane flow valve restrictor as a compensating element. The four different Recess geometries of the bearing studied in the present study are a square Recessed bearing, a circular Recessed bearing, an elliptical Recessed bearing and a triangular Recessed bearing. The equation governing the flow of lubricant in a journal bearing together with 3D elasticity equation and restrictor flow equation are solved by using the Finite Element Method. The study describes the effect of Recess shape, bearing flexibility and a method of compensation on the performance characteristics of a hydrostatic/hybrid journal bearing system. A comparative performance of the membrane compensated hydrostatic/hybrid journal bearing system has also been studied vis-a-vis capillary, orifice and constant flow valve restrictors. The results presented in this study amply demonstrate that the shape of Recess/pocket of a hydrostatic/hybrid flexible journal bearing system affects the performance of the bearing quite appreciably and a proper selection of Recess shape along with a suitable compensating device is needed to get an improved performance from the bearing.

  • performance of hydrostatic hybrid journal bearings with unconventional Recess geometries
    Tribology Transactions, 1998
    Co-Authors: Satish C. Sharma, S C Jain, Narendra Singh, R Sinhasan, Shant K Singh
    Abstract:

    A theoretical study using FEM is performed of multiRecess capillary compensated hydrostatic/hybrid journal bearings which find use in number of engineering applications. In this study, bearings having four different Recess shapes were observed for their static and dynamic performance parameters which include minimum film thickness, flow rate, rotordynamic coefficients and threshold speed. The bearings with four different Recess geometries included in the present study were a square Recess bearing, a circular Recess bearing a triangular Recess bearing and an elliptical Recess bearing. Comparisons of performance characteristics were made to determine which Recess shape gives the best performance. The results presented in this paper are expected to help machine tool designers make better use of the Recess shapes. Presented at the 52nd Annual Meeting In Kansas City, Missouri May 10–22, 1997