scholarly journals The Influence of Finite-Wall Conductance on Load Capacity of the Magnetohydrodynamic Slider Bearing

1964 ◽  
Vol 86 (3) ◽  
pp. 436-440 ◽  
Author(s):  
W. T. Snyder
Keyword(s):  
Pressure Distribution ◽  
Load Capacity ◽  
Substantial Reduction ◽  
Open Circuit ◽  
External Loading ◽  
Slider Bearing ◽  
Wall Conductivity ◽  
Open Circuit Condition ◽  
Special Case ◽  
Fluid Conductivity

An analysis is presented which considers the influence of finite-wall conductance on the pressure distribution and load capacity of the magnetohydrodynamic slider bearing. The analysis is based on general external loading conditions with the open-circuit condition being a special case. The load capacity is a linear function of the quantity Φ = Es/V By and the dependence of Φ on the conductivity and thickness of the walls is shown in explicit form. Curves showing the variation of Φ with wall conductance are presented. A numerical example is included which indicates a substantial reduction of load capacity from the case of insulating walls to the case where the wall conductivity is 1 percent of the fluid conductivity.

Magnetohydrodynamic Effects in Composite Bearings

1967 ◽  
Vol 89 (3) ◽  
pp. 323-328 ◽  
Author(s):  
J. Prakash
Keyword(s):  
Hartmann Number ◽  
Load Capacity ◽  
Short Circuit ◽  
Electrical Energy ◽  
Open Circuit ◽  
Slider Bearing ◽  
Frictional Drag ◽  
Electrically Conducting ◽  
Open Circuit Condition ◽  
Composite Bearing

A theoretical analysis is made of a composite slider bearing using an electrically conducting lubricant such as a liquid metal in the presence of a magnetic field applied perpendicular to the bearing surfaces. Two solutions are presented for large and small values of Hartmann number. It is found that for large Hartmann number significant increase in load capacity can be obtained even under open circuit condition. Short circuit condition results in zero load capacity, under the approximation considered. At small Hartmann number only a slight increase occurs under open circuit condition and external power must be supplied to get a significant increase. It is seen that a magnetohydrodynamic composite bearing does not always give an increase in load capacity as compared to an equivalent inclined slider bearing, as is the case with classical composite bearing. There is a critical Hartmann number depending on the parameters of the problem, above which MHD effects reduce the load capacity as compared to the case of an equivalent inclined slider bearing. It is also observed that the frictional drag on the bearing can be made zero by supplying electrical energy through the electrodes to the fluid.

Dynamics of Interstitial Fluid Pressure in Extracellular Matrix Hydrogels in Microfluidic Devices

2015 ◽  
Vol 137 (9) ◽  
Author(s):  
Joe Tien ◽  
Le Li ◽  
Ozgur Ozsun ◽  
Kamil L. Ekinci
Keyword(s):  
Extracellular Matrix ◽  
Pressure Distribution ◽  
Interstitial Fluid ◽  
Scaling Laws ◽  
Fluid Pressure ◽  
Interstitial Fluid Pressure ◽  
External Loading ◽  
Interstitial Pressure ◽  
Time Resolved ◽  
Long Time

In order to understand how interstitial fluid pressure and flow affect cell behavior, many studies use microfluidic approaches to apply externally controlled pressures to the boundary of a cell-containing gel. It is generally assumed that the resulting interstitial pressure distribution quickly reaches a steady-state, but this assumption has not been rigorously tested. Here, we demonstrate experimentally and computationally that the interstitial fluid pressure within an extracellular matrix gel in a microfluidic device can, in some cases, react with a long time delay to external loading. Remarkably, the source of this delay is the slight (∼100 nm in the cases examined here) distension of the walls of the device under pressure. Finite-element models show that the dynamics of interstitial pressure can be described as an instantaneous jump, followed by axial and transverse diffusion, until the steady pressure distribution is reached. The dynamics follow scaling laws that enable estimation of a gel's poroelastic constants from time-resolved measurements of interstitial fluid pressure.

Centrifugal Effects in Hydrostatic Porous Thrust Bearing

1979 ◽  
Vol 101 (3) ◽  
pp. 381-385 ◽  
Author(s):  
R. S. Gupta ◽  
V. K. Kapur
Keyword(s):  
Pressure Distribution ◽  
Thrust Bearing ◽  
Load Capacity ◽  
Bearing Material

In this analysis the customary neglected centrifugal effects on the performance of hydrostatic porous thrust bearing with incompressible lubricant has been studied and the effects of their interaction of pressure distribution and load capacity illustrate the possibility of replacement of the nonporous bearing material by porous one.

The Contribution of In-Line IMU Inspection to Geohazard and Crack Management Strategies

2021 ◽  
Author(s):  
Andy Young ◽  
Andrew Wilde ◽  
Ivan Grosmann
Keyword(s):  
Management Practices ◽  
Load Capacity ◽  
Management Strategies ◽  
High Strength ◽  
Ground Movement ◽  
Ground Subsidence ◽  
Measurement Unit ◽  
External Loading ◽  
Integrity Management ◽  
The Right

Abstract Geohazards and external loads are a significant threat to the integrity of pipelines in hilly terrain, at river crossings and where ground subsidence is taking place. Well designed pipelines can tolerate strains that exceed the nominal strain of 0.5% that corresponds specified minimum yield strengths, however the presence of weld defects and stress corrosion cracking can reduce the load capacity dramatically. Welds that are to specification but are under-matched on actual strength to the adjacent parent pipe have also been recognised as potentially vulnerable to low strain failures in high strength pipes. Modern pipelines in terrain susceptible to geohazards normally include design studies to identify and avoid or mitigate the threats. Surveillance of the right-of-way is also routinely carried out for pipelines with good integrity management practices, and particularly for major strategic lines. In-line inspection using an inertial measurement unit (IMU) is a well-known method to detect ground movement loads and contributes to the integrity management of pipelines. In this paper we illustrate : 1. How IMU inspection is an important tool in the management of geohazards and how it compliments other methods of geohazard assessment. 2. How locations of elevated pipe strain are identified and evaluated for external loading threats, and can be aligned with other data sets that indicate the pipeline load capacity. 3. How the locations of bending strain can be prioritised for further action. 4. How the loading profile in the pipeline can be incorporated into crack management strategies in order prioritise locations for further investigation or assessment.

Pathways of ion movement in the canine tracheal epithelium

1980 ◽  
Vol 239 (3) ◽  
pp. F215-F221 ◽  
Author(s):  
M. J. Welsh ◽  
J. H. Widdicombe
Keyword(s):  
Open Circuit ◽  
Paracellular Pathway ◽  
Tracheal Epithelium ◽  
Ion Movement ◽  
Voltage Dependent ◽  
Transepithelial Voltage ◽  
Unidirectional Fluxes ◽  
Open Circuit Condition ◽  
Hydrophilic Molecule ◽  
Cl Permeability

The pathways of ion movement across canine tracheal epithelium, a Cl-secreting tissue, were examined by three techniques. First, the measurement of simultaneous, unidirectional fluxes of Na or Cl and mannitol, a large hydrophilic molecule that serves as a marker of the paracellular pathway, indicated that a significant fraction of both the Na flux from submucosa to mucosa (J Na sm) and the flux of Cl from mucosa to submucosa (J Cl ms) traverse the cellular pathway. The ratio of the Na-to-Cl diffusion coefficients through the paracellular pathway was 0.23, in contrast to the free solution ratio of 0.63. Second, in voltage-clamp experiments we examined the effect of transepithelial voltage differences on the unidirectional fluxes of Na and Cl. The results agree with the previous findings, suggesting that there are voltage-independent, or transcellular, backfluxes of Na and Cl, and that the relative permeability of Na to Cl through the voltage-dependent (presumably paracellular) pathway was 0.28. Third, measurement of transepithelial diffusion potentials gave a Na-to-Cl permeability ratio of 0.31 +/- 0.02 (mean +/- SE). These results suggest that there are significant transcellular backfluxes of Na and Cl and that the paracellular pathway in the canine trachea is anion selective. An anion-selective pathway would tend to shunt the secreted Cl back through the paracellular pathway, thus minimizing the net ion and fluid movement across the tissue in the open-circuit condition.

Computational fluid dynamic study on the tribological performance of dimple-textured surface fabricated using the turning process

2019 ◽  
Vol 71 (4) ◽  
pp. 594-602 ◽  
Author(s):  
Haniff Abdul Rahman ◽  
Jaharah A. Ghani ◽  
Wan Mohd Faizal Wan Mahmood ◽  
Mohammad Rasidi Mohammad Rasani
Keyword(s):  
Pressure Distribution ◽  
Load Capacity ◽  
Surface Texturing ◽  
Tribological Performance ◽  
Future Application ◽  
Textured Surface ◽  
Turning Process ◽  
Equal Distribution ◽  
Content Type ◽  
First Case

Purpose This study aims to simulate the influence of surface texturing produced via turning process toward pressure distribution and load capacity generation using computational fluid dynamics (CFD). Design/methodology/approach The dimple geometry was obtained via turning process, to be used for future application on piston skirt surfaces. Two cases were studied: a preliminary study using single periodic dimple assuming linear dimple distribution and an application study using multiple periodic dimples to address actual dimple orientation following the turning process. Findings For the first case, the dimple was proven to generate load capacity with regard to untextured surface, owing to the asymmetric pressure distribution. Increasing the Reynolds number, dimple width and dimple depth was found to increase load capacity. For the second case, although load capacity increases via surface texturing, the value was 97.4 per cent lower relative to the first case. This confirmed the importance of doing multiple dimple simulations for real applications to achieve more realistic and accurate results. Originality/value A new concept of dimple fabrication using a low-cost turning process has been developed, with a potential to increase the tribological performance under hydrodynamic lubrication. Previous CFD simulations to simulate these benefits have been done using a single periodic dimple, assuming equal distribution array between dimples. However, due to the different orientations present for dimples produced using turning process, a single periodic dimple simulation may not be accurate, and instead, multiple dimple simulation is required. Therefore, present research was conducted to compare the results between these two cases and to ensure the accuracy of CFD simulation for this type of dimple.

scholarly journals Experimental Research on Power Transformer Vibration Distribution under Different Winding Defect Conditions

Electronics ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 842
Author(s):  
Yiwei Hu ◽  
Jing Zheng ◽  
Hai Huang
Keyword(s):  
Spatial Distribution ◽  
Vibration Analysis ◽  
Power Transformer ◽  
Open Circuit ◽  
Distribution Characteristics ◽  
Spatial Distribution Characteristics ◽  
Three Phase ◽  
Transformer Winding ◽  
Faults Diagnosis ◽  
Open Circuit Condition

Vibration analysis is one of the important tools for the transformer winding faults diagnosis. Previous researchers have proved that the vibration spatial distribution of the winding is significantly influenced by the winding defects for the open circuit condition. In order to study the effects of the loading current on the winding vibrations under different mechanical conditions, experiments were designed and operated on a three-phase transformer winding to analyze the winding vibration distribution under different winding defect cases. Further, to study to what extent the mechanical defects and the loading current influence characteristics of the vibration distribution on the tank, the tank vibration distribution under various winding defects and different loading currents were also measured and discussed. In addition, the possibility of detection of transformer winding faults based on tank vibration spatial distribution characteristics was also discussed.

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