Open Access. Powered by Scholars. Published by Universities.®

Mechanical Engineering Commons

Open Access. Powered by Scholars. Published by Universities.®

Other Materials Science and Engineering

Mechanical Engineering Publications

Articles 1 - 2 of 2

Full-Text Articles in Mechanical Engineering

Broadband Measurement Of Rate-Dependent Viscoelasticity At Nanoscale Using Scanning Probe Microscope: Poly(Dimethylsiloxane) Example, Zhonghua Xu, Kyongsoo Kim, Qingze Zou, Pranav Shrotriya Sep 2008

Broadband Measurement Of Rate-Dependent Viscoelasticity At Nanoscale Using Scanning Probe Microscope: Poly(Dimethylsiloxane) Example, Zhonghua Xu, Kyongsoo Kim, Qingze Zou, Pranav Shrotriya

Mechanical Engineering Publications

A control approach to achieve nanoscale broadband viscoelasticmeasurement using scanning probe microscope(SPM) is reported. Current SPM-based force measurement is too slow to measure rate-dependent phenomena, and large (temporal) measurement errors can be generated when the sample itself changes rapidly. The recently developed model-less inversion-based iterative control technique is used to eliminate the dynamics and hysteresis effects of the SPM hardware on the measurements, enabling rapid excitation and measurement of rate-dependent material properties. The approach is illustrated by the mechanical characterization of poly(dimethylsiloxane) over a broad frequency range of three orders of magnitude (∼1 Hz to 4.5 KHz).


Effect Of Sample Aging On The Accuracy Of The International Energy Agency's Tar Measurement Protocol, Ming Xu, Robert C. Brown, Glenn Norton Jan 2006

Effect Of Sample Aging On The Accuracy Of The International Energy Agency's Tar Measurement Protocol, Ming Xu, Robert C. Brown, Glenn Norton

Mechanical Engineering Publications

The Working Group of the Biomass Gasification Task of the International Energy Agency (IEA) Bioenergy Agreement has developed a protocol for sampling and analysis of tar and particulates from biomass gasifiers, which is commonly accepted as a standard for reliable measurement of tar in producer gas. The methodology is dependent upon dissolving tar in a solvent for subsequent recovery by evaporation or distillation. This paper investigates whether storage of the tar/solvent sample prior to analysis affects the accuracy of the tar measurement. On the basis of the results of this study, we recommend that samples be analyzed within a ...