scholarly journals Transient in situ measurement of kombucha biofilm growth and mechanical properties

2021 ◽  
Author(s):  
Pascal Bertsch ◽  
Danai Etter ◽  
Peter Fischer
Keyword(s):  
Mechanical Properties ◽  
In Situ Measurement ◽  
Biofilm Growth

Kombucha is a traditional beverage obtained by the fermentation of sugared tea by a symbiotic culture of bacteria and yeast which has recently re-emerged as a popular lifestyle product with...

Measurement of Cement in Situ Stresses and Mechanical Properties Without Cooling or Depressurization

2021 ◽  
Author(s):  
Meng Meng ◽  
Luke Frash ◽  
James Carey ◽  
Wenfeng Li ◽  
Nathan Welch ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Elastic Modulus ◽  
Poisson’S Ratio ◽  
Axial Stress ◽  
Triaxial Compression ◽  
In Situ Measurement ◽  
Poisson's Ratio ◽  
Ambient Conditions

Abstract Accurate characterization of oilwell cement mechanical properties is a prerequisite for maintaining long-term wellbore integrity. The drawback of the most widely used technique is unable to measure the mechanical property under in situ curing environment. We developed a high pressure and high temperature vessel that can hydrate cement under downhole conditions and directly measure its elastic modulus and Poisson's ratio at any interested time point without cooling or depressurization. The equipment has been validated by using water and a reasonable bulk modulus of 2.37 GPa was captured. Neat Class G cement was hydrated in this equipment for seven days under axial stress of 40 MPa, and an in situ measurement in the elastic range shows elastic modulus of 37.3 GPa and Poisson's ratio of 0.15. After that, the specimen was taken out from the vessel, and setted up in the triaxial compression platform. Under a similar confining pressure condition, elastic modulus was 23.6 GPa and Possion's ratio was 0.26. We also measured the properties of cement with the same batch of the slurry but cured under ambient conditions. The elastic modulus was 1.63 GPa, and Poisson's ratio was 0.085. Therefore, we found that the curing condition is significant to cement mechanical property, and the traditional cooling or depressurization method could provide mechanical properties that were quite different (50% difference) from the in situ measurement.

scholarly journals Quantitative optical coherence elastography based on fiber-optic probe for in situ measurement of tissue mechanical properties

2016 ◽  
Vol 7 (2) ◽  
pp. 688 ◽  
Author(s):  
Yi Qiu ◽  
Yahui Wang ◽  
Yiqing Xu ◽  
Namas Chandra ◽  
James Haorah ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fiber Optic ◽  
In Situ Measurement ◽  
Optical Coherence ◽  
Fiber Optic Probe ◽  
Optic Probe

Dynamics of Nanoparticle Chain Aggregates of Carbon Under Tension

2003 ◽  
Vol 778 ◽  
Author(s):  
Rajdip Bandyopadhyaya ◽  
Weizhi Rong ◽  
Yong J. Suh ◽  
Sheldon K. Friedlander
Keyword(s):  
Mechanical Properties ◽  
Carbon Black ◽  
Polymer Film ◽  
Elastic Behavior ◽  
Small Strains ◽  
Transmission Electron ◽  
Chain Aggregates ◽  
Nanoparticle Chains ◽  
Reinforcing Filler

AbstractCarbon black in the form of nanoparticle chains is used as a reinforcing filler in elastomers. However, the dynamics of the filler particles under tension and their role in the improvement of the mechanical properties of rubber are not well understood. We have studied experimentally the dynamics of isolated nanoparticle chain aggregates (NCAs) of carbon made by laser ablation, and also that of carbon black embedded in a polymer film. In situ studies of stretching and contraction of such chains in the transmission electron microscope (TEM) were conducted under different maximum values of strain. Stretching causes initially folded NCA to reorganize into a straight, taut configuration. Further stretching leads to either plastic deformation and breakage (at 37.4% strain) or to a partial elastic behavior of the chain at small strains (e.g. 2.3% strain). For all cases the chains were very flexible under tension. Similar reorientation and stretching was observed for carbon black chains embedded in a polymer film. Such flexible and elastic nature of NCAs point towards a possible mechanism of reinforcement of rubber by carbon black fillers.

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