Kinetics of relaxation processes in shock waves and condensing gas flows

Abstract 1. It is shown that the process of stress relaxation at different initial elongations as well as the process of deformation at constant rate for unloaded rubbers at different temperatures (20–70° C) can be represented quantitatively by equations suggested in earlier works. Likewise the possibility of expanding the theories proposed for the kinetics of high-elastic deformation of spatial polymers is substantiated. 2. It is shown that the relaxation properties of soft unloaded vulcanizates of natural rubber and many synthetic rubbers do not undergo essential changes during vulcanization. 3. The conjecture is expressed that the invariability of the relaxation properties during vulcanization continues until the bonds of the spatial network are distributed sufficiently widely not to influence the activity or heat movement of the chain segments between them.

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Fast relaxation processes in a protein revealed by the decay kinetics of tryptophan fluorescence

Biochemistry ◽

10.1021/bi00722a019 ◽

1974 ◽

Vol 13 (25) ◽

pp. 5170-5178 ◽

Cited By ~ 72

Author(s):

A. Grinvald ◽

I. Z. Steinberg

Keyword(s):

Tryptophan Fluorescence ◽

Relaxation Processes ◽

Decay Kinetics ◽

Fast Relaxation ◽

Kinetics Of

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Near-source characteristics of two-phase gas–solid outbursts in roadways

International Journal of Coal Science & Technology ◽

10.1007/s40789-020-00362-9 ◽

2020 ◽

Author(s):

Aitao Zhou ◽

Meng Zhang ◽

Kai Wang ◽

Derek Elsworth

Keyword(s):

Shock Waves ◽

Numerical Models ◽

Gas Flows ◽

Far Field ◽

Two Phase ◽

Emergency Rescue ◽

Source Characteristics ◽

Basic Parameters ◽

Significant Attenuation ◽

Coal And Gas Outbursts

Abstract Coal and gas outbursts compromise two-phase gas–solid mixtures as they propagate as shock waves and flows from their sources. Propagation is influenced by the form of the outburst, proximity to source, the structure and form of the transmitting roadways and the influence of obstacles. The following characterizes the propagation of coal and gas outbursts as two-phase gas–solid flows proximal to source where the coupled effects of pulverized coal and gas flows dominate behavior. The characteristics of shock wave propagation and attenuation were systematically examined for varied roadway geometries using experiments and numerical models. The results demonstrate that the geometry of roadway obstructions is significant and may result in partial compression and sometimes secondary overpressurization in blocked and small corner roadways leading to significant attenuation of outburst shock waves. The shock waves attenuate slowly in both straight and abruptly expanding roadways and more significantly in T-shaped roadways. The most significant attenuation appears in small angle corners and bifurcations in roadways with the largest attenuation occurring in blocked roadways. These results provide basic parameters for simplifying transport in complex roadway networks in the far-field, and guidance for the design of coal and gas outburst prevention facilities and emergency rescue.

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Learning benefits by integrating design, manufacturing, and testing in a course for compressible flow visualizations

International Journal of Mechanical Engineering Education ◽

10.1177/0306419019838279 ◽

2019 ◽

Vol 48 (4) ◽

pp. 297-314

Author(s):

Barbara S Linke ◽

Lee Martin ◽

Ian Garretson

Keyword(s):

Shock Waves ◽

Experimental Testing ◽

Learning Experience ◽

Sustainable Manufacturing ◽

Aerospace Engineering ◽

Gas Flows ◽

Interdisciplinary Field ◽

Flow Visualizations ◽

Hydraulic Analogy ◽

Design And Manufacture

Although engineering is by nature an applied and interdisciplinary field, courses in engineering can lead even the best students to develop knowledge that is disconnected from other related fields and from conditions of application. This paper describes an innovative undergraduate course that integrated the theory of shock waves, computational modeling, experimental testing, and science of sustainable manufacturing. The course supported better visualization of mechanical and aerospace engineering phenomena, such as shock waves in supersonic gas flows, by utilizing the hydraulic analogy of shallow water and a simple water table. Airfoil design and manufacture were integrated through aerospace and manufacturing theory and application. For the first course offering, student learning was assessed with regard to their views of engineering, learning experience, and transfer of learning. The course proved to increase self-efficacy as engineers, as well as their self-reported confidence in working comfortably on multi-disciplinary teams. Furthermore, scenario-based assessments confirmed that the students were able to integrate aerospace and manufacturing theory and application within new scenarios.

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