scholarly journals EXPERIMENTAL STUDIES OF TRANSIENT EFFECTS IN FAST REACTOR FUELS. SERIES III. PRE-IRRADIATED MIXED OXIDE (PuO$sub 2$-UO$sub 2$) IRRADIATIONS. INTERIM REPORT. STEADY-STATE IRRADIATIONS

1965 ◽  
Author(s):  
J.E. Hanson ◽  
S.A. Rabin
Keyword(s):  
Steady State ◽  
Fast Reactor ◽  
Mixed Oxide ◽  
Experimental Studies ◽  
Interim Report ◽  
Transient Effects

Effects of slide-to-roll ratio and varying velocity on the lubrication performance of grease at low speed

2021 ◽  
pp. 135065012199336
Author(s):  
Yiming Han ◽  
Jing Wang ◽  
Xuyang Jin ◽  
Shanshan Wang ◽  
Rui Zhang
Keyword(s):  
Steady State ◽  
Critical Speed ◽  
Industrial Applications ◽  
Transient Effects ◽  
Disintegration Time ◽  
Low Speed ◽  
Existence Time ◽  
Pure Rolling ◽  
Lubrication Performance ◽  
Long Time

Under steady-state pure rolling conditions with low speed, the thickener fiber agglomerations can be maintained for a long time, generating a beneficial thicker film thickness. However, in industrial applications, motions with sliding or transient effects are very common for gears, rolling-element bearings or even chain drives, evaluation of the grease performance under such conditions is vital for determining the lubrication mechanism and designing new greases. In this project, optical interferometry experiments were carried out on a ball-disk test rig to study the disintegration time of the grease thickener agglomerations with the increase of the slide-to-roll ratio under steady-state and reciprocation motions. Under steady-state conditions, the thickener fiber agglomeration can exist for a while and the time becomes shorter with the increase of the slide-to-roll ratio above the critical speed. Below the critical speed, the thickener fiber can exist in the contact in the form of a quite thick film for a very long time under pure rolling conditions but that time is decreased with the increase of the slide-to-roll ratio. The introduction of the transient effect can further reduce the existence time of the thickener.

scholarly journals Magnetoactive elastomers for magnetically tunable vibrating sensor systems

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Tatiana I. Becker ◽  
Yuriy L. Raikher ◽  
Oleg V. Stolbov ◽  
Valter Böhm ◽  
Klaus Zimmermann
Keyword(s):  
Magnetic Field ◽  
Steady State ◽  
Smart Materials ◽  
Excitation Frequency ◽  
Experimental Studies ◽  
Uniform Field ◽  
Sensor Systems ◽  
Ongoing Research ◽  
Amplification Ratio ◽  
Field Distortion

Abstract Magnetoactive elastomers (MAEs) are a special type of smart materials consisting of an elastic matrix with embedded microsized particles that are made of ferromagnetic materials with high or low coercivity. Due to their composition, such elastomers possess unique magnetic field-dependent material properties. The present paper compiles the results of investigations on MAEs towards an approach of their potential application as vibrating sensor elements with adaptable sensitivity. Starting with the model-based and experimental studies of the free vibrational behavior displayed by cantilevers made of MAEs, it is shown that the first bending eigenfrequency of the cantilevers depends strongly on the strength of an applied uniform magnetic field. The investigations of the forced vibration response of MAE beams subjected to in-plane kinematic excitation confirm the possibility of active magnetic control of the amplitude-frequency characteristics. With change of the uniform field strength, the MAE beam reveals different steady-state responses for the same excitation, and the resonance may occur at various ranges of the excitation frequency. Nonlinear dependencies of the amplification ratio on the excitation frequency are obtained for different magnitudes of the applied field. Furthermore, it is shown that the steady-state vibrations of MAE beams can be detected based on the magnetic field distortion. The field difference, which is measured simultaneously on the sides of a vibrating MAE beam, provides a signal with the same frequency as the excitation and an amplitude proportional to the amplitude of resulting vibrations. The presented prototype of the MAE-based vibrating unit with the field-controlled “configuration” can be implemented for realization of acceleration sensor systems with adaptable sensitivity. The ongoing research on MAEs is oriented to the use of other geometrical forms along with beams, e.g. two-dimensional structures such as membranes.

Initial Investigations Into the Dynamics of Cutting Brushes for Sweeping

2002 ◽  
Vol 124 (4) ◽  
pp. 675-681 ◽  
Author(s):  
G. M. Peel ◽  
G. A. Parker
Keyword(s):  
Steady State ◽  
Centrifugal Force ◽  
Transient Effects ◽  
Test Rig ◽  
Low Speeds ◽  
Discretized Model

Cutting brushes are used at relatively low speeds by various municipal vehicles and in particular road sweeping units. As the name suggests such brushes are designed to “cut” through debris, especially compacted sand or similar matter. The main deflection plane of a bristle (or tine) is along the mount radius, making the tines very stiff in the direction of rotation, hence the cutting action when the brush is rotated. Exploring the literature shows that very little is known, or understood, about the operation of brushes for mechanical sweeping. In this paper a pseudo-static discretized model is developed to investigate the deformations and forces acting on brushes during ideal operation of a horizontal brush on a flat plane. Due to the numerous different sweeper brushes on the market, one common configuration is used as the basis of the model and the paper will detail only the characteristics of this brush. The brush to be investigated is a “cutting brush,” introduced above, where the tines can only deflect along the mount radius. Having developed a model it is used to predict the forces and torques generated within a horizontally rotating brush. The influence of centrifugal force is analyzed although transient effects are neglected and steady state conditions assumed. The predictions of the model are compared to practical results taken from a test rig and the validity of the model is discussed. Agreement between the model and the practical results will be shown to be good, considering the complexities and practical realities involved in analyzing any system which is friction dependent.

scholarly journals Estimates of Michaelis-Menten Constants for the Two Membranes of the Brain Endothelium

1984 ◽  
Vol 4 (2) ◽  
pp. 241-249 ◽  
Author(s):  
Albert Gjedde ◽  
Ove Christensen
Keyword(s):  
Steady State ◽  
Endothelial Cell ◽  
Transport Properties ◽  
Glucose Transport ◽  
Cell Membranes ◽  
Experimental Studies ◽  
Facilitated Diffusion ◽  
Capillary Endothelial Cells ◽  
The Individual ◽  
Tracer Experiments

Tracer studies on facilitated diffusion across the blood–brain barrier lead to the calculation of Michaelis-Menten constants that describe the rate of transport. However, the barrier consists of two endothelial cell membranes, and the relevance of single Michaelis-Menten constants in relation to the two cell membranes is unknown. We have formulated a model of two endothelial cell membranes and show that the measured Michaelis-Menten constants are simple functions of the properties of the individual membranes when transport across the endothelium is rapid ( P1 > 10−6 cm s−1). We also show that the Michaelis-Menten constants determined in tracer experiments describe facilitated diffusion in the steady state only if the two membranes have similar transport properties. As an application of this observation, we have examined three experimental studies that measure glucose transport in the steady state and show that the Michaelis-Menten constants for glucose transport calculated from the tracer experiments are equal to the constants calculated from the steady-state experiments. We conclude that the luminal and abluminal membranes of brain capillary endothelial cells have equal glucose transport properties.

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