Infrared Emission Spectra of Elastohydrodynamic Contacts

1976 ◽  
Vol 98 (2) ◽  
pp. 230-235 ◽  
Author(s):  
J. L. Lauer ◽  
M. E. Peterkin
Keyword(s):  
Contact Region ◽  
Radiant Energy ◽  
Emission Spectra ◽  
Infrared Emission ◽  
Operating Conditions ◽  
Test Fluid ◽  
Two Fluids ◽  
Spectral Bands ◽  
Ball Surface ◽  
Lower Fluid

A small diamond disk mounted as a window in a steel plate was covered with test fluid, and a weighted steel ball was rotated over the window so as to form a sliding elastohydrodynamic (EHD) contact region. Some of the radiant energy generated in this region, both in the fluid and at the boundaries, passed through the window into an infrared interferometer, giving rise to an emission spectrum. This spectrum could be separated into contributions from the fluid and from the ball surface, making it possible, by appropriate calibrations, to estimate their temperatures separately under operating conditions. Moreover, the shape of the discrete spectral bands of the fluid permitted some inferences on its state. Two fluids were studied under identical mechanical conditions, a polyester and a naphthenic oil, each containing an equal amount of polymethylstyrene as a spectral indicator. Differences of band intensity, band width, and frequency could, therefore, be attributed to differences in the behavior of the base fluid. The principal results were much lower fluid temperatures and lower metal surface temperatures when the polyester was used than when the naphthenic oil was similarly used. Polyester films were also thicker and of higher density than naphthenic oil films under the same conditions. This work is only the beginning of a comprehensive study of EHD contacts by infrared spectroscopy, but the results already achieved lead to interesting speculations on the mechanisms of EHD processes, which further study is expected to elucidate.

scholarly journals Analysis of Emission Infrared Spectra of Protein Solutions in Low Concentrations

2020 ◽  
Vol 8 ◽  
Author(s):  
Nikita Penkov ◽  
Nadezda Penkova
Keyword(s):  
Emission Spectra ◽  
Infrared Emission ◽  
Water Control ◽  
Three Solutions ◽  
Buffer Solution ◽  
Radiation Level ◽  
Low Concentration ◽  
Spectral Bands ◽  
Distant Effect ◽  
Low Concentrations

In this work, based on the method of infrared emission spectroscopy, the study of emission spectra of interferon-gamma (IFNγ) solution in a mixture or surrounded by three low-concentration solutions (IFNγ, antibodies to IFNγ, glycine buffer) or water control was performed. First of all, the solutions of low concentrations themselves were studied. It was shown that low-concentration solutions of IFNγ and antibodies to IFNγ had lower emission intensity in three spectral bands near 800, 1,300 and 2000 cm−1 compared to water control. Glycine buffer solution had a radiation level indistinguishable from that of the control. In this work, the effect of adding these low-concentration solutions to IFNγ (1 mg/ml) was compared to the effect of adding water control to IFNγ. All solutions or water were added in 10% (v/v). It was found that adding each of the three test solutions induced an increase in the radiation intensity of the IFNγ solution in the spectral range of 400–1700 cm−1 (compared to the IFNγ solution with control spike). It was also tested whether the radiation of the studied low-concentration solutions surrounding the IFNγ solution (1 mg/ml) affected the IFNγ radiation. The measurement results were compared to the data obtained for IFNγ surrounded by water control. All three solutions were found to exert a distant effect on the IFNγ solution (1 mg/ml), which was manifested in a decrease in the intensity of its radiation near 1,000 and 1,500 cm−1 compared to the control solution of IFNγ. Thus, the emission spectra of low-concentration aqueous solutions were measured for the first time, and differences in the emission spectra of the IFNγ solution depending on low-concentration additives and the environment were shown. The paper interprets the observed differences and discusses possible mechanisms underlying the observed phenomena.

Study of Polyphenyl Ether Fluid (5P4E) in Operating Elastohydrodynamic Contacts by Infrared Emission Spectroscopy

1979 ◽  
Vol 101 (1) ◽  
pp. 67-73 ◽  
Author(s):  
J. L. Lauer
Keyword(s):  
Emission Spectroscopy ◽  
Emission Spectra ◽  
Elastic Solid ◽  
Infrared Emission ◽  
Operating Conditions ◽  
Sliding Contact ◽  
Critical Shear Rate ◽  
Shear Rates ◽  
Polyphenyl Ether ◽  
High Shear Rates

Infrared emission spectra of 5P4E polyphenyl ether were obtained from an operating elastohydrodynamic sliding contact at different speeds and loads by Fourier emission microspectrophotometry. The spectra were found to be polarized with respect to the direction of the conjunction line, especially at high shear rates. Film and metal surface temperatures were calculated from the spectra, and film thicknesses were determined under various operating conditions. Changes of polarized band structure above a critical shear rate, at which the slope of the film temperature versus shear curve changes abruptly and at which the film thickness assumes a minimum value, are consistent with a transition of the lubricant from a viscous liquid to a visco-elastic liquid or to an elastic solid.

Infrared Emission Spectroscopy as a Reliability Tool

1999 ◽  
Author(s):  
Q. Kim ◽  
S. Kayali
Keyword(s):  
Spatial Resolution ◽  
Emission Spectroscopy ◽  
Hot Spot ◽  
Cost Effective ◽  
Infrared Emission ◽  
Test System ◽  
Operating Conditions ◽  
Yield Enhancement ◽  
Infrared Emission Spectroscopy ◽  
Channel Temperature

Abstract In this paper, we report on a non-destructive technique, based on IR emission spectroscopy, for measuring the temperature of a hot spot in the gate channel of a GaAs metal/semiconductor field effect transistor (MESFET). A submicron-size He-Ne laser provides the local excitation of the gate channel and the emitted photons are collected by a spectrophotometer. Given the state of our experimental test system, we estimate a spectral resolution of approximately 0.1 Angstroms and a spatial resolution of approximately 0.9 μm, which is up to 100 times finer spatial resolution than can be obtained using the best available passive IR systems. The temperature resolution (<0.02 K/μm in our case) is dependent upon the spectrometer used and can be further improved. This novel technique can be used to estimate device lifetimes for critical applications and measure the channel temperature of devices under actual operating conditions. Another potential use is cost-effective prescreening for determining the 'hot spot' channel temperature of devices under normal operating conditions, which can further improve device design, yield enhancement, and reliable operation. Results are shown for both a powered and unpowered MESFET, demonstrating the strength of our infrared emission spectroscopy technique as a reliability tool.

The Use of Ratio-Recording Interferometry for the Measurement of Infrared Emission Spectra: Applications to Oxide Films on Copper Surfaces

1975 ◽  
Vol 29 (6) ◽  
pp. 496-500 ◽  
Author(s):  
D. Kember ◽  
N. Sheppard
Keyword(s):  
Emission Spectra ◽  
Black Body ◽  
Infrared Emission ◽  
Thin Layers ◽  
Oxide Surface ◽  
Surface Layers ◽  
Selective Reflection ◽  
Copper Surfaces ◽  
Emission And Absorption Spectra ◽  
Direct Correspondence

Infrared emission spectra from metal samples with oxide surface layers are shown to be very advantageously studied using the spectrum-ratioing facility of a recording infrared interferometer. The emission from a given sample is ratioed against that from a black-body emitter at the same temperature so as to give emittance as a function of wavenumber directly. This method has very useful application to irregularly shaped metal emitters. In the absence of selective reflection there is a direct correspondence between emission and absorption spectra for thin layers of an emitting substance. However, the presence of selective reflection leads to reduced emission and to considerable differences in the appearance of “absorption” and emission spectra in regions of strong absorption. Emission spectra obtained from copper plates heated, above 150°C, for different periods in air are shown clearly to indicate the presence of cuprous, Cu(I), and cupric, Cu(II), oxides in the surface layer.

Infrared emission spectra of BeH2 and BeD2

2003 ◽  
Vol 118 (8) ◽  
pp. 3622-3627 ◽  
Author(s):  
A. Shayesteh ◽  
K. Tereszchuk ◽  
P. F. Bernath ◽  
R. Colin
Keyword(s):  
Emission Spectra ◽  
Infrared Emission

Temperature Gradients Through EHD Films and Molecular Alignment Evidenced By Infrared Spectroscopy

1981 ◽  
Vol 103 (1) ◽  
pp. 65-73 ◽  
Author(s):  
V. W. King ◽  
J. L. Lauer
Keyword(s):  
Absorption Spectrum ◽  
Emission Spectra ◽  
Infrared Emission ◽  
Molecular Alignment ◽  
Temperature Gradients ◽  
Spectral Change ◽  
Continuum Source ◽  
Polyphenyl Ether ◽  
Elementary Analysis ◽  
Gap Width

Partial and complete emission band reversals have been observed in the infrared emission spectra from portions of operating sliding contacts. An elementary analysis has been carried out to show that partial reversals are due to temperature gradients in the fluid film—the film acts both as a radiation-emitter and absorber, and that total reversals—an emission spectrum appears as an absorption spectrum—are likely to be due to a continuum source, such as hot solid asperities. The total energy radiated under the latter conditions exceeds that under the others. A decrease in gap width with increased load was accompanied by a dramatic spectral change in the case of 5P4E polyphenyl ether, which is indicative of molecular alignment.

scholarly journals Modeling the Anharmonic Infrared Emission Spectra of PAHs: Application to the Pyrene Cation

2020 ◽  
pp. 95-102
Author(s):  
M. Basire ◽  
P. Parneix ◽  
T. Pino ◽  
Ph. Bréchignac ◽  
F. Calvo
Keyword(s):  
Emission Spectra ◽  
Infrared Emission

Gas Turbine Exhaust Emissions Monitoring Using Nonintrusive Infrared Spectroscopy

1998 ◽  
Vol 120 (3) ◽  
pp. 514-518 ◽  
Author(s):  
M. Hilton ◽  
A. H. Lettington ◽  
C. W. Wilson
Keyword(s):  
Gas Turbine ◽  
Molecular Species ◽  
Tomographic Reconstruction ◽  
Emission Spectra ◽  
Exhaust Emissions ◽  
Infrared Emission ◽  
High Spectral Resolution ◽  
Rotational Line ◽  
Spectroscopic Techniques ◽  
Reconstruction Procedure

Infrared (IR) spectra of the exhaust emissions from a static gas turbine engine have been studied using Fourier Transform (FT) spectroscopic techniques. Passive detection of the infrared emission from remote (range ∼ 3 m) hot exhaust gases was obtained nonintrusively using a high spectral resolution (0.25 cm−1) FTIR spectrometer. Remote gas temperatures were determined from their emission spectra using the total radiant flux method or by analysis of rotational line structure. The HITRAN database of atmospheric species was used to model the emission from gas mixtures at the relevant temperatures. The spatial distribution of molecular species across a section transverse to the exhaust plume ∼10 cm downstream of the jet pipe nozzle was studied using a tomographic reconstruction procedure. Spectra of the infrared emission from the plume were taken along a number of transverse lines of sight from the centerline of the engine outwards. A mathematical matrix inversion technique was applied to reconstruct the molecular concentrations of CO and CO2 in concentric regions about the centerline. Quantitative measurement of the molecular species concentrations determined nonintrusively were compared with results from conventional extractive sampling techniques.

scholarly journals Infrared Emission Spectra of CaF2-CaO-SiO2 Melt.

2000 ◽  
Vol 40 (8) ◽  
pp. 739-743 ◽  
Author(s):  
Shigeru Ueda ◽  
Hirotaka Koyo ◽  
Takashi Ikeda ◽  
Yoshiharu Kariya ◽  
Masafumi Maeda
Keyword(s):  
Emission Spectra ◽  
Infrared Emission
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