Model-based analysis of the role of biological, hydrological and geochemical factors affecting uranium bioremediation

2011 ◽  
Vol 108 (7) ◽  
pp. 1537-1548 ◽  
Author(s):  
Jiao Zhao ◽  
Timothy D. Scheibe ◽  
R. Mahadevan
Keyword(s):  
Factors Affecting ◽  
Model Based ◽  
Geochemical Factors ◽  
Model Based Analysis

Model-Based Analysis of Friction-Induced Sub-Synchronous Whirl for a Rotor Contacting With Clearance Bearings Under Axial Load

2015 ◽  
Author(s):  
Matthew O. T. Cole ◽  
Lawrence Hawkins
Keyword(s):  
Axial Load ◽  
Coulomb Friction ◽  
Friction Forces ◽  
Root Finding ◽  
Model Based ◽  
Simple Physical Interpretation ◽  
Level Of Agreement ◽  
Model Based Analysis

For rotors supported by active magnetic bearings (AMBs), clearance bearings are commonly used to provide backup support under loss of AMB functionality. Test data from real machines shows that rotor vibration during touchdown on backup bearings may involve steady forward whirling at a sub-synchronous frequency. This excitation is believed to be due to friction forces transmitted between the rotor and a bearing end-face under axial load. This paper proposes a new analytical approach to model and predict such friction-driven forward whirl behaviors. A set of constraint equations are derived that relate a circular whirl motion of arbitrary orbital speed to the frequency response functions of the rotor-housing structure. This model is coupled with an evaluation of Coulomb friction associated with slip between the rotor and the supporting end-face of a thrust bearing. The resulting equations can be used to compute a set of possible whirl motions via a root-finding procedure. A case study is undertaken for a 140 kW energy storage flywheel. Model-based predictions are compared with measured data from spin-down tests and show a good level of agreement. The study confirms the role of friction-related forces in driving forward-whirl response behaviors. It also highlights the key role of housing and machine support characteristics in response behavior. This influence is shown to be complex and not open to simple physical interpretation. Therefore, the proposed analytical method is seen as a useful tool to investigate this influence while avoiding the need for time consuming numerical simulations.

Model-Based Analysis of Friction-Induced Subsynchronous Whirl for a Rotor Contacting With Clearance Bearings Under Axial Load

2016 ◽  
Vol 138 (7) ◽  
Author(s):  
Matthew O. T. Cole ◽  
Lawrence Hawkins
Keyword(s):  
Axial Load ◽  
Coulomb Friction ◽  
Friction Forces ◽  
Root Finding ◽  
Model Based ◽  
Simple Physical Interpretation ◽  
Level Of Agreement ◽  
Model Based Analysis

For rotors supported by active magnetic bearings (AMBs), clearance bearings are commonly used to provide backup support under loss of AMB functionality. Test data from real machines shows that vibration during touchdown on backup bearings may involve steady forward whirling of the rotor with a subsynchronous frequency. This excitation is believed to be due to friction forces transmitted between the rotor and a bearing end-face under axial load. This paper proposes a new analytical approach to model and predict such friction-driven forward whirl behaviors. A set of constraint equations are derived that relate a circular whirl motion of arbitrary orbital speed to the frequency response functions for the rotor-housing structure. This model is coupled with an evaluation of Coulomb friction associated with slip between the rotor and the supporting end-face of a thrust bearing. The resulting equations can be used to compute a set of possible whirl motions via a root-finding procedure. A case study is undertaken for a 140 kW energy storage flywheel. Model-based predictions are compared with measured data from spin-down tests and show a good level of agreement. The study confirms the role of friction-related forces in driving forward-whirl response behaviors. It also highlights the key role of housing and machine support characteristics in response behavior. This influence is shown to be complex and not open to simple physical interpretation. Therefore, the proposed analytical method is seen as a useful tool to investigate this influence while avoiding the need for time consuming numerical simulations.

scholarly journals Tight glycemic control in critical care – The leading role of insulin sensitivity and patient variability: A review and model-based analysis

2011 ◽  
Vol 102 (2) ◽  
pp. 156-171 ◽  
Author(s):  
J. Geoffrey Chase ◽  
Aaron J. Le Compte ◽  
Fatanah Suhaimi ◽  
Geoffrey M. Shaw ◽  
Adrienne Lynn ◽  
...  
Keyword(s):  
Critical Care ◽  
Insulin Sensitivity ◽  
Glycemic Control ◽  
Tight Glycemic Control ◽  
Model Based ◽  
Leading Role ◽  
Model Based Analysis

Exploring the role of GS–GOGAT cycle in microcystin synthesis and regulation – a model based analysis

2017 ◽  
Vol 13 (12) ◽  
pp. 2603-2614 ◽  
Author(s):  
Swarnendu Banerjee ◽  
Abhishek Subramanian ◽  
Joydev Chattopadhyay ◽  
Ram Rup Sarkar
Keyword(s):  
Kinetic Model ◽  
Model Based ◽  
Gene Regulatory ◽  
Model Based Analysis

First kinetic model of microcystin regulation that explains the biochemical and gene regulatory events linking environmental nitrogen change with microcystin.

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