Dielectric properties of oil–water complexes using terahertz transmission spectroscopy

Using Terahertz Time-Domain Spectroscopy to Discriminate among Water Contamination Levels in Diesel Engine Oil

“…The overall refractive indices were in good agreement with a study of polyglycol oils with water levels ranging from 0.43% to 3.28% (Gorenflo et al, 2006), in that higher water concentrations resulted in higher refractive indices with relatively distinct, equidistant curves. Most studies of oils have resulted in refractive indices that decrease as frequency increases.…”

“…Lubricating oil characterization with THz-TDS includes polyglycol oils with water (Gorenflo et al, 2006), mineral oil with additives (Naftaly et al, 2005), six grades of lubricating oil (Tian et al, 2009), oil base stock and additive (Tian et al, 2012), and vegetable oils (Hu et al, 2005;Li, 2010). Our recent study was able to distinguish among three grades of unused gasoline engine oil and predict viscosity (Abdul-Munaim et al, 2015).…”

Material thickness optimization for transmission-mode terahertz time-domain spectroscopy

“…Some applications that require a remarkably low uncertainty in measurement include quantify-(C) 2008 OSAing the sample amount [7,8,9], determining resonance frequencies [10], etc. In certain cases, a lower uncertainty assists the interpretation of data at a critical point.…”

Sensing the hygroscopicity of polymer and copolymer materials using terahertz time-domain spectroscopy

“…The α DH ðωÞ is the absorption coefficient of a dehydrated polymer (after drying at 80°C) and α w ðωÞ is the absorption coefficient of distilled water at 1 THz. Here, c x denotes the water absorption, which is also known as the water concentration [30]. Rearranging the above equation gives the following formula to calculate the amount water absorbed by the samples:…”

“…The speed of light is denoted as c 0 . The hygroscopicity is determined by using the linear absorption model, which can be written as follows [30]:…”