Dynamics of Solids and Fluids, Conservation of Momentum of Material and Control Volumes

1995 ◽  
pp. 397-474
Author(s):  
Franz Ziegler
Keyword(s):  
Conservation Of Momentum ◽  
Control Volumes ◽  
And Control

Orifice Contraction Coefficient for Inviscid Incompressible Flow

1985 ◽  
Vol 107 (1) ◽  
pp. 36-43 ◽  
Author(s):  
R. D. Grose
Keyword(s):  
Stokes Equations ◽  
Inviscid Flow ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Contraction Coefficient ◽  
Two Dimensional Flow ◽  
Conservation Of Momentum ◽  
Orifice Flow ◽  
Contraction Effect ◽  
Control Volumes

The theory for steady flow of an incompressible fluid through an orifice has been semi-empirically established for only certain flow conditions. In this paper, the development of a more rigorous theory for the prediction of the orifice flow contraction effect is presented. This theory is based on the conservation of momentum and mass principles applied to global control volumes for continuum flow. The control volumes are chosen to have a particular geometric construction which is based on certain characteristics of the Navier-Stokes equations for incompressible and, in the limit, inviscid flow. The treatment is restricted to steady incompressible, single phase, single component, inviscid Newtonian flow, but the principles that are developed hold for more general conditions. The resultant equations predict the orifice contraction coefficient as a function of the upstream geometry ratio for both axisymmetric and two-dimensional flow fields. The predicted contraction coefficient values agree with experimental orifice discharge coefficient data without the need for empirical adjustment.

Attitude maneuver control of liquid-filled spacecraft with unknown inertia and disturbances

2019 ◽  
Vol 25 (8) ◽  
pp. 1460-1469 ◽  
Author(s):  
Xiao Juan Song ◽  
Shu Feng Lu
Keyword(s):  
Control Strategy ◽  
Sliding Mode ◽  
Adaptive Sliding Mode Control ◽  
Underactuated System ◽  
Mass Model ◽  
Attitude Maneuver ◽  
Dynamics And Control ◽  
Conservation Of Momentum ◽  
And Control ◽  
The Mathematical Model

The attitude maneuver dynamics and control strategy for a fuel-filled spacecraft with uncertain inertia and external disturbances are studied. The mathematical model of a three-axis stabilized spacecraft is established based on the law of conservation of momentum, and the liquid fuel inside the partially-filled fuel tank is represented by an equivalent two-mode spring-mass model. The adaptive sliding mode control law is designed for this kind of underactuated system, and the Lyapunov stability analysis guarantees that all system trajectories reach and remain on the sliding surface. Then, the multiple mode input shapers are used to suppress the sloshing of the fluid fuel. The numerical results show good performance and effectiveness of the control strategy.

THE TRANSIENT TEMPERATURE PREDICTION IN THE DEEPWATER RISERLESS WELL

2021 ◽  
pp. 1-15
Author(s):  
Ming Feng ◽  
Catalin Teodoriu ◽  
Jerome J. Schubert
Keyword(s):  
Temperature Distribution ◽  
Transient Temperature ◽  
Transfer Model ◽  
Temperature Prediction ◽  
Thermal Problem ◽  
Well Integrity ◽  
Operational Safety ◽  
Control Volumes ◽  
Transient Thermal ◽  
And Control

Abstract The purpose of study is to analyze the transient thermal problem of the circulation fluids in the riserless well, which is critical to well integrity, and thus to operational safety of the well. The transient heat transfer model is based on the theory of the energy balance and control volumes to solve the downhole circulation fluids temperature distribution in a riserless well. Examples demonstrate the calculated circulation fluids temperature distribution in the wellbore by using this model.

Control of Metal Alloy Oxidation with Electric Fields

1973 ◽  
Vol 31 ◽  
pp. 164-165
Author(s):  
R. R. Dils ◽  
P. S. Follansbee
Keyword(s):  
Electric Fields ◽  
Oxidation Process ◽  
Base Alloy ◽  
Oxide Surface ◽  
Platinum Electrodes ◽  
Insulating Layer ◽  
Iron Base Alloy ◽  
Alloy Oxidation ◽  
Aluminum Oxide Layer ◽  
And Control

Electric fields have been applied across oxides growing on a high temperature alloy and control of the oxidation of the material has been demonstrated. At present, three-fold increases in the oxidation rate have been measured in accelerating fields and the oxidation process has been completely stopped in a retarding field.The experiments have been conducted with an iron-base alloy, Pe 25Cr 5A1 0.1Y, although, in principle, any alloy capable of forming an adherent aluminum oxide layer during oxidation can be used. A specimen is polished and oxidized to produce a thin, uniform insulating layer on one surface. Three platinum electrodes are sputtered on the oxide surface and the specimen is reoxidized.

Evidence for a Blood Ganglion Barrier in the Superior Cervical Ganglion of the Rat

1982 ◽  
Vol 40 ◽  
pp. 204-204
Author(s):  
D. M. DePace
Keyword(s):  
Blood Vessels ◽  
Superior Cervical Ganglion ◽  
Peripheral Nerves ◽  
Time Schedule ◽  
Transmission Electron ◽  
Cervical Ganglion ◽  
The Central Nervous System ◽  
Cervical Ganglia ◽  
Capillary Circulation ◽  
And Control

The majority of blood vessels in the superior cervical ganglion possess a continuous endothelium with tight junctions. These same features have been associated with the blood brain barrier of the central nervous system and peripheral nerves. These vessels may perform a barrier function between the capillary circulation and the superior cervical ganglion. The permeability of the blood vessels in the superior cervical ganglion of the rat was tested by intravenous injection of horseradish peroxidase (HRP). Three experimental groups of four animals each were given intravenous HRP (Sigma Type II) in a dosage of.08 to.15 mg/gm body weight in.5 ml of.85% saline. The animals were sacrificed at five, ten or 15 minutes following administration of the tracer. Superior cervical ganglia were quickly removed and fixed by immersion in 2.5% glutaraldehyde in Sorenson's.1M phosphate buffer, pH 7.4. Three control animals received,5ml of saline without HRP. These were sacrificed on the same time schedule. Tissues from experimental and control animals were reacted for peroxidase activity and then processed for routine transmission electron microscopy.

Effects of renovascular hypertension on rat adrenal zona glomerulosa

1978 ◽  
Vol 36 (2) ◽  
pp. 582-583
Author(s):  
G. Mazzocchi ◽  
P. Rebuffat ◽  
C. Robba ◽  
P. Vassanelli ◽  
G. G. Nussdorfer
Keyword(s):  
Renovascular Hypertension ◽  
Left Kidney ◽  
Renin Angiotensin System ◽  
Plasma Renin ◽  
Zona Glomerulosa ◽  
Ultrastructural Changes ◽  
Albino Rats ◽  
Left Renal Artery ◽  
Angiotensin System ◽  
And Control

It is well known that the rat adrenal zona glomerulosa steroidogenic activity is controlled by the renin-angiotensin system. The ultrastructural changes in the rat zona glomerulosa cells induced by renovascular hypertension were described previously, but as far as we are aware no correlated biochemical and morphometric investigations were performed.Twenty adult male albino rats were divided into 2 experimental groups. One group was subjected to restriction of blood flow to the left kidney by the application of a silver clip about the left renal artery. The other group was sham-operated and served as a control. Renovascular hypertension developed in about 10 days: sistolic blood pressure averaged 165 ± 6. 4 mmHg, whereas it was about 110 ± 3. 8 mmHg in the control animals. The hypertensive and control rats were sacrificed 20 days after the operation. The blood was collected and plasma renin activity was determined by radioimmunological methods. The aldosterone concentration was radioimmunologically assayed both in the plasma and in the homogenate of the left capsular adrenal gland.

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