scholarly journals Mechanical Dissipation Below 1μHz with a Cryogenic Diamagnetic Levitated Micro-Oscillator

2021 ◽  
Vol 15 (2) ◽  
Author(s):  
Yingchun Leng ◽  
Rui Li ◽  
Xi Kong ◽  
Han Xie ◽  
Di Zheng ◽  
...  
Keyword(s):  
Mechanical Dissipation

Monitoring of Polymer Plastication in the Injection Moulding Process

2013 ◽  
Author(s):  
Thuy Linh Pham ◽  
Jean Balcaen ◽  
Sambor Chhay ◽  
Yves Bereaux ◽  
Jean-Yves Charmeau
Keyword(s):  
Injection Moulding ◽  
Optical Glass ◽  
Experimental Studies ◽  
Fibre Length ◽  
Rotation Frequency ◽  
Direct Function ◽  
Moulding Process ◽  
Melt Pool ◽  
Injection Moulding Process ◽  
Mechanical Dissipation

In injection moulding or in extrusion, plastication is the step during which polymer pellets are melted by the means of mechanical dissipation provided by a rotating screw and by thermal conduction coming from a heated metallic barrel. This step is crucial for melt thermal homogeneity, charge dispersion and fibre length preservation. Although there have been a large number of theoretical and experimental studies of plastication during the past decades, mostly on extrusion and mostly using the screw extraction technique, extremely few of them have dealt with trying to visualise plastication, let alone measuring the plastication profile in real-time. As a matter of fact, designing such an equipment is an arduous task. We designed an industry-sized metallic barrel, featuring 3 optical glass windows; each window possessing 3 plane faces itself to allow for visualisation and record by synchronised cameras and lightening by lasers. The images recorded can be further analysed by digital image processing. Preliminary results confirm the plastication theory and show a compacted solid bed and a melt pool side by side. The total plastication length is a direct function of screw rotation frequency as it is obvious from results on the melt pool width, which increases when the screw rotation frequency decreases. However, some evidence of solid bed breakage has been recorded, whereby the solid bed does not diminish continuously along the screw but is fractured in the compression zone.

Comparison of the temperature dependence of the mechanical dissipation in thin films of Ta 2 O 5 and Ta 2 O 5 doped with TiO 2

2009 ◽  
Vol 26 (15) ◽  
pp. 155012 ◽  
Author(s):  
I W Martin ◽  
E Chalkley ◽  
R Nawrodt ◽  
H Armandula ◽  
R Bassiri ◽  
...  
Keyword(s):  
Thin Films ◽  
Temperature Dependence ◽  
Mechanical Dissipation

Mechanical dissipation in optical microresonators

2008 ◽  
Author(s):  
Georg Anetsberger ◽  
Albert Schliesser ◽  
Remi Riviere ◽  
Olivier Arcizet ◽  
T. J. Kippenberg
Keyword(s):  
Optical Microresonators ◽  
Mechanical Dissipation

On the theoretical foundations of thin solid and liquid shells

2016 ◽  
Vol 22 (3) ◽  
pp. 343-371 ◽  
Author(s):  
Roger A Sauer ◽  
Thang X Duong
Keyword(s):  
Weak Form ◽  
Material Behavior ◽  
Momentum Balance ◽  
Power Balance ◽  
Equilibrium Equations ◽  
Material Stability ◽  
Out Of Plane ◽  
Mechanical Dissipation ◽  
Theoretical Foundations ◽  
Unified Description

This paper gives a concise summary of the general theoretical framework suitable to describe shells with solid-like and liquid-like behavior. Thin-shell kinematics are considered and used to derive the equilibrium equations from linear- and angular-momentum balance. Based on the mechanical power balance and the mechanical dissipation inequality, the constitutive equations for the hyperelastic material behavior of constrained shells are derived and their material stability is examined. Various constitutive examples are considered and assessed for their stability. The governing weak form of the formulation is derived and decomposed into in-plane and out-of-plane components. The presented work provides a very general framework for a unified description of solid and liquid shells and illustrates what leads to their loss of material stability. This framework serves as a basis for developing computational shell formulations based on rotation-free shell discretizations. Therefore the full linearization of the formulation is also presented here.

Experimental measurements of mechanical dissipation associated with dielectric coatings formed using SiO 2 , Ta 2 O 5 and Al 2 O 3

2006 ◽  
Vol 23 (15) ◽  
pp. 4953-4965 ◽  
Author(s):  
D R M Crooks ◽  
G Cagnoli ◽  
M M Fejer ◽  
G Harry ◽  
J Hough ◽  
...  
Keyword(s):  
Experimental Measurements ◽  
Dielectric Coatings ◽  
Mechanical Dissipation
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