Electrical impedance spectroscopy device for measurement of moisture gradients in wood

Abstract

A prototype of the electrical impedance spectroscopy (EIS) device for the measurement of internal moisture gradients in wood was developed. The EIS device consists of a hand-held probe connected to a control unit interfaced with a portable personal computer and a power unit. In the measurement, parallel flat electrodes of the measuring probe are laid against the wood specimen and the sine wave excitation is applied in the frequency range 1–100 kHz. The measured amplitude and phase spectral data were analyzed using the model based on constant phase elements. A spectral analysis software package was designed for measurement of subsurface transverse moisture gradients. The EIS device was tested with many types of uniform, desorption, and absorption gradients in lumber, pulpwood, and log specimens from spruce, pine, and birch. The EIS device can be easily transferred in a small case allowing field measurements.

Applicability of Vis-NIR hyperspectral imaging for monitoring wood moisture content (MC)

“…Neutron radiography gives rise to images with high resolution (Mannes et al 2009 ;Hass et al 2010 ;Rosner et al 2012 ). Electrical impedance spectroscopy (Tiitta and Olkkonen 2002 ) and X-ray computerized tomography (X-ray CT) (Wiberg and Moren 1999 ) were proven to be useful for obtaining more detailed information about the water distribution within objects. X-ray CT in general also affords an internal water distribution pattern with a high spatial resolution.…”

Electrical properties of wood colonized by Gloeophyllum trabeum

“…Furthermore, it is likely that the decayed samples contained moisture gradients. It is known that moisture gradients influence resistance based electrical measurements (Tiitta and Olkkonen, 2002). The presence of moisture gradients may have influenced the shape of the calibration curve as well as the decayed wood blocks.…”

Compact Wide Frequency Range Fractional-Order Models of Human Body Impedance against Contact Currents

“…This model is very similar to that used in [22] to represent the impedance data of a wood sample used to estimate the internal moisture gradients. Model three given in Figure 4(c) is composed of three resistors ( 0,1,2 ) and two CPEs ( 1,2 , 1,2 ) with impedance given by…”