scholarly journals Depolarization Ratio of the ν1 Raman Band of Pure CH4 and Perturbed by N2 and CO2

Molecules ◽  
2021 ◽  
Vol 27 (1) ◽  
pp. 144
Author(s):  
Aleksandr S. Tanichev ◽  
Dmitry V. Petrov
Keyword(s):  
Carbon Dioxide ◽  
Raman Spectroscopy ◽  
Raman Spectrum ◽  
Pressure Range ◽  
Raman Band ◽  
High Sensitivity ◽  
Gas Analysis ◽  
Depolarization Ratio ◽  
Single Pass ◽  
Pure Methane

In this work, the effect of nitrogen and carbon dioxide on the depolarization ratio of the ν1 band of methane in the pressure range of 0.1–5 MPa is studied. A high-sensitivity single-pass Raman spectrometer was used to obtain accurate results. Moreover, we took into account the overlap of the ν1 band by the ν3 and ν2 + ν4 bands using the simulation of their spectra. The depolarization ratio of the ν1 band in pure methane is within 0–0.001, and the effect of nitrogen and carbon dioxide on this parameter is negligible in the indicated pressure range. The obtained results are useful for correct simulation of the Raman spectrum of methane at different pressures, which is necessary to improve the accuracy of gas analysis methods using Raman spectroscopy.

scholarly journals Depolarization Ratios of Methane Raman Bands as a Function of Pressure

Molecules ◽  
2020 ◽  
Vol 25 (8) ◽  
pp. 1951
Author(s):  
Dmitry Petrov
Keyword(s):  
Raman Spectroscopy ◽  
High Pressure ◽  
Natural Gas ◽  
Raman Spectra ◽  
Pressure Dependence ◽  
Pressure Range ◽  
Gas Composition ◽  
Depolarization Ratio ◽  
Depolarization Ratios

In this work, we measured the intensities of Q-branches of the ν1, ν2 and ν3 bands in the polarized and depolarized methane Raman spectra in the pressure range of 1–60 atm. It was established that the pressure dependence of depolarization ratios of the ν2 and ν3 bands are negligible. In turn, the depolarization ratio of the ν1 band increases with increasing pressure and reaches approximately 0.0045 at 60 atm. These data are more precise than previously published ones because ν1 band intensities were determined taking into account the contribution of overlapping lines of ν3 band. The presented data will be useful in calculating the methane polarizabilities at high pressure, as well as in calculating methane Raman spectra for measuring the natural gas composition using Raman spectroscopy.

Fuzzy Approach for Identifying Artistic Pigments with Raman Spectroscopy

2009 ◽  
Vol 63 (8) ◽  
pp. 947-957 ◽  
Author(s):  
R. Perez-Pueyo ◽  
M. J. Soneira ◽  
M. Castanys ◽  
S. Ruiz-Moreno
Keyword(s):  
Decision Making ◽  
Raman Spectroscopy ◽  
Fuzzy Logic ◽  
Raman Spectrum ◽  
Raman Spectra ◽  
Fuzzy System ◽  
Raman Band ◽  
Decision Making Process ◽  
Fuzzy Approach ◽  
Spectrum Measurement

In this work, a fuzzy approach for automatically identifying artistic pigments from their Raman spectra is presented. The uncertainty introduced during the Raman spectrum measurement of pigments is considered in the design of the fuzzy system. The position of the Raman bands in the unknown spectrum can be subject to small displacements due to noise, misalignments in the calibration, etc. Fuzzy logic allows us to work with this uncertainty and to design a system based on the comparison between the Raman band positions in an unknown spectrum recorded from an artwork and the Raman band positions in spectra recorded from reference pigments gathered in databases. The fuzzy system provides the reference pigments whose Raman band positions match those of the unknown pigment analyzed and gives guidance to the decision-making process in the final identification.

scholarly journals Metal Oxide Nanorods-Based Sensor Array for Selective Detection of Biomarker Gases

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1922
Author(s):  
Gwang Su Kim ◽  
Yumin Park ◽  
Joonchul Shin ◽  
Young Geun Song ◽  
Chong-Yun Kang
Keyword(s):  
Real Time ◽  
Sensor Array ◽  
High Sensitivity ◽  
Gas Analysis ◽  
Diagnostic Methods ◽  
Real Time Monitoring ◽  
Non Invasive ◽  
Sensitivity And Selectivity ◽  
Breath Gas Analysis ◽  
Angle Method

The breath gas analysis through gas phase chemical analysis draws attention in terms of non-invasive and real time monitoring. The array-type sensors are one of the diagnostic methods with high sensitivity and selectivity towards the target gases. Herein, we presented a 2 × 4 sensor array with a micro-heater and ceramic chip. The device is designed in a small size for portability, including the internal eight-channel sensor array. In2O3 NRs and WO3 NRs manufactured through the E-beam evaporator’s glancing angle method were used as sensing materials. Pt, Pd, and Au metal catalysts were decorated for each channel to enhance functionality. The sensor array was measured for the exhaled gas biomarkers CH3COCH3, NO2, and H2S to confirm the respiratory diagnostic performance. Through this operation, the theoretical detection limit was calculated as 1.48 ppb for CH3COCH3, 1.9 ppt for NO2, and 2.47 ppb for H2S. This excellent detection performance indicates that our sensor array detected the CH3COCH3, NO2, and H2S as biomarkers, applying to the breath gas analysis. Our results showed the high potential of the gas sensor array as a non-invasive diagnostic tool that enables real-time monitoring.

Validation of transcutaneous carbon dioxide monitoring using an artificial lung during adult pulsatile cardiopulmonary bypass

2021 ◽  
pp. 039139882098785
Author(s):  
Lawrence Garrison ◽  
Jeffrey B Riley ◽  
Steve Wysocki ◽  
Jennifer Souai ◽  
Hali Julick
Keyword(s):  
Carbon Dioxide ◽  
Cardiopulmonary Bypass ◽  
Gold Standard ◽  
Blood Gas Analysis ◽  
Gas Analysis ◽  
Artificial Lung ◽  
Blood Gas ◽  
Median Difference ◽  
Transcutaneous Carbon Dioxide ◽  
Arterial Blood

Measurements of transcutaneous carbon dioxide (tcCO2) have been used in multiple venues, such as during procedures utilizing jet ventilation, hyperbaric oxygen therapy, as well as both the adult and neo-natal ICUs. However, tcCO2 measurements have not been validated under conditions which utilize an artificial lung, such cardiopulmonary bypass (CPB). The purpose of this study was to (1) validate the use of tcCO2 using an artificial lung during CPB and (2) identify a location for the sensor that would optimize estimation of PaCO2 when compared to the gold standard of blood gas analysis. tcCO2 measurements ( N = 185) were collected every 30 min during 54 pulsatile CPB procedures. The agreement/differences between the tcCO2 and the PaCO2 were compared by three sensor locations. Compared to the earlobe or the forehead, the submandibular PtcCO2 values agreed best with the PaCO2 and with a median difference of –.03 mmHg (IQR = 5.4, p < 0.001). The small median difference and acceptable IQR support the validity of the tcCO2 measurement. The multiple linear regression model for predicting the agreement between the submandibular tcCO2 and PaCO2 included the SvO2, the oxygenator gas to blood flow ratio, and the native perfusion index ( R2 = 0.699, df = 1, 60; F = 19.1, p < 0.001). Our experience in utilizing tcCO2 during CPB has demonstrated accuracy in estimating PaCO2 when compared to the gold standard arterial blood gas analysis, even during CO2 flooding of the surgical field.

scholarly journals Overview of Popular Techniques of Raman Spectroscopy and Their Potential in the Study of Plant Tissues

Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1537
Author(s):  
Aneta Saletnik ◽  
Bogdan Saletnik ◽  
Czesław Puchalski
Keyword(s):  
Raman Spectroscopy ◽  
Cell Walls ◽  
Structural Changes ◽  
Spatial Information ◽  
Technological Development ◽  
Analytical Techniques ◽  
High Sensitivity ◽  
Plant Tissues ◽  
Wide Range ◽  
Identification Technique

Raman spectroscopy is one of the main analytical techniques used in optical metrology. It is a vibration, marker-free technique that provides insight into the structure and composition of tissues and cells at the molecular level. Raman spectroscopy is an outstanding material identification technique. It provides spatial information of vibrations from complex biological samples which renders it a very accurate tool for the analysis of highly complex plant tissues. Raman spectra can be used as a fingerprint tool for a very wide range of compounds. Raman spectroscopy enables all the polymers that build the cell walls of plants to be tracked simultaneously; it facilitates the analysis of both the molecular composition and the molecular structure of cell walls. Due to its high sensitivity to even minute structural changes, this method is used for comparative tests. The introduction of new and improved Raman techniques by scientists as well as the constant technological development of the apparatus has resulted in an increased importance of Raman spectroscopy in the discovery and defining of tissues and the processes taking place in them.

Raman Studies of the Adduct Structure of Cl2 and Br2 with Piaselenole

1980 ◽  
Vol 34 (6) ◽  
pp. 636-638
Author(s):  
J. J. Blaha ◽  
W. Brittain ◽  
C. E. Meloan ◽  
W. G. Fateley
Keyword(s):  
Molecular Structure ◽  
Raman Spectroscopy ◽  
Raman Spectrum ◽  
Long Time

The affinity of 2,1,3-benzoselenadiazole, commonly called piaselenole, for chlorine and bromine molecules has been known for a long time. Raman spectroscopy provides a very interesting method for determining the molecular structure of these 1:1 adducts. The Raman spectrum shows the Cl2 and Br2 molecules in the adduct remain as a dimer molecule.

Adsorption isotherms and kinetics of carbon dioxide on Chinese dry coal over a wide pressure range

Adsorption ◽  
2015 ◽  
Vol 21 (1-2) ◽  
pp. 53-65 ◽  
Author(s):  
Yongchen Song ◽  
Wanli Xing ◽  
Yi Zhang ◽  
Weiwei Jian ◽  
Zhaoyan Liu ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Adsorption Isotherms ◽  
Pressure Range ◽  
Adsorption Isotherms And Kinetics ◽  
Wide Pressure Range ◽  
Kinetics Of ◽  
Wide Pressure
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