scholarly journals Terahertz Time Domain Spectroscopy to Detect Different Oxidation Levels of Diesel Engine Oil

Lubricants ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 18 ◽  
Author(s):  
Ali Abdul-Munaim ◽  
Jan Ornik ◽  
Martin Koch ◽  
Dennis Watson
Keyword(s):  
Refractive Index ◽  
Diesel Engine ◽  
Time Domain ◽  
Measurement Method ◽  
Oxidation Time ◽  
Engine Oil ◽  
Terahertz Time Domain Spectroscopy ◽  
Time Domain Spectroscopy ◽  
Thz Range

Diesel engine oil was subjected to thermal oxidization (TO) for six periods of time (0 h, 24 h, 48 h, 72 h, 96 h, and 120 h) and was subsequently characterized by terahertz time domain spectroscopy (THz-TDS). The THz refractive index generally increased with oxidation time. The measurement method illustrated the potential of THz-TDS when a fixed setup with a single cuvette is used. A future miniaturized setup installed in an engine would be an example of a fixed setup. For the refractive index, there were highly significant differences among the oxidation times across most of the 0.3–1.7 THz range.

Evaluating Oil Potential in Shale Formations Using Terahertz Time-Domain Spectroscopy

2017 ◽  
Vol 140 (3) ◽  
Author(s):  
Yizhang Li ◽  
Xinyang Miao ◽  
Honglei Zhan ◽  
Wei Wang ◽  
Rima Bao ◽  
...  
Keyword(s):  
Refractive Index ◽  
Time Domain ◽  
Oil Shale ◽  
Powdered Material ◽  
Specimen Preparation ◽  
Evolutionary Stage ◽  
Terahertz Time Domain Spectroscopy ◽  
Time Domain Spectroscopy ◽  
The Difference ◽  
Different Response

Optical assessment of oil shale using terahertz time-domain spectroscopy (THz-TDS) was carried out to study oil potential. Fischer assay testing was employed to obtain the oil yield of oil shale specimens to examine the difference of oil potential between oil shale samples from three regions: Beipiao, Barkol, and Huadian in China. Then, two types of specimens from each area were prepared for the optical tests and the results were compared. The refractive index (n) at 0.2–1.2 THz was derived; n decreased slowly with increasing frequency for all the specimens despite the oscillation pattern observed at lower frequencies. The specimen preparation method that mixed the powdered material led to minor differences between the specimens. The different response of kerogen to the terahertz pulse depending on the kerogen's evolutionary stage leads to a difference in the refractive index between the specimens from the various regions. This study indicates that using THz-TDS to evaluate the oil content in oil shale without inducing reaction within the specimen can be an effective method for resource exploration.

Accurate Complex Refractive Index with Standard Deviation of ZnTe Measured by Terahertz Time Domain Spectroscopy

2013 ◽  
Vol 52 (4R) ◽  
pp. 042401 ◽  
Author(s):  
Saroj R. Tripathi ◽  
Makoto Aoki ◽  
Masanori Takeda ◽  
Toshiaki Asahi ◽  
Iwao Hosako ◽  
...  
Keyword(s):  
Refractive Index ◽  
Standard Deviation ◽  
Time Domain ◽  
Complex Refractive Index ◽  
Terahertz Time Domain Spectroscopy ◽  
Time Domain Spectroscopy

scholarly journals Nondestructive Interface Morphology Characterization of Thermal Barrier Coatings Using Terahertz Time-Domain Spectroscopy

Coatings ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 89 ◽  
Author(s):  
Dongdong Ye ◽  
Weize Wang ◽  
Jibo Huang ◽  
Xiang Lu ◽  
Haiting Zhou
Keyword(s):  
Refractive Index ◽  
Thermal Barrier Coatings ◽  
Time Domain ◽  
Thermal Barrier ◽  
Interface Morphology ◽  
Terahertz Time Domain Spectroscopy ◽  
Barrier Coatings ◽  
Time Domain Spectroscopy ◽  
Thickness Loss ◽  
Thz Waves

In this work, a terahertz time-domain spectroscopy (THz-TDS) system was used to measure the thickness of thermal barrier coatings (TBCs) and characterize the interface morphology of TBCs after erosion. Reflection mode, with an angle of incidence of 0, was used for inspection before and after erosion. The refractive index, thickness, and internal structure evolution tendency of the yttria-stabilized zirconia (YSZ) top coat were estimated under consideration of the interaction between the pulsed THz waves and the TBCs. The surface roughness of the top coat surface was considered for the errors analysis in the refractive index and thickness measurement. To reduce the errors introduced by the refractive index change after erosion, two mathematical models were built to assess the thickness loss. Then, the thickness loss was compared with results estimated by the micrometer inspection method. Finally, the basic erosion sample profile with Ra roughness was obtained, and the broadening of THz pulses were suggested as a possible measure for the top coat porosity change, showing that THz waves can be a novel online non-destructive and non-contact evaluation method that can be widely utilized to evaluate the integrity of TBCs applied to gas turbine blades.

Research of Beta-Endosulfan Based on THz Time-Domain Spectroscopy

2013 ◽  
Vol 718-720 ◽  
pp. 1060-1065 ◽  
Author(s):  
Zhe Liu ◽  
Xian Li ◽  
Fei Heng Yue ◽  
Lu Feng ◽  
Jin Hui Cai ◽  
...  
Keyword(s):  
Refractive Index ◽  
Organic Pollutants ◽  
Time Domain ◽  
Spectral Properties ◽  
Experimental Results ◽  
Good Match ◽  
Terahertz Time Domain Spectroscopy ◽  
Time Domain Spectroscopy ◽  
Characteristic Absorption ◽  
System Part

THz spectral properties between 0.2-1.5THz of beta-endosulfan, one of the persistent organic pollutants (POPs), are investigated based on the THz time domain system. Part of the characteristic absorption peaks are theoretically analyzed by Dmol3 modular program. The experimental results show that the average refractive index of beta-endosulfan in the THz waveband is about 1.005 and characteristic absorption peaks exist at 0.67, 0.80, 1.03, 1.14, 1.26 and 1.46THz. The absorption peaks at 0.67THz and 1.03THz have a good match with the theoretic absorption peak positions which appear at 0.72THz and 1.07THz calculated by Dmol3. The peaks at 0.67THz and 1.03THz may be caused by the torsion in B and C direction of beta-endosulfan crystal lattice, along with the translation in A direction. Compared with the experimental results of alpha-endosulfan, it can be seen clearly that these two isomers have completely different absorption peaks. For further it indicates that terahertz time domain spectroscopy (THz-TDS) has great application value in identifying isomers.

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