Article
Optics
Shaomin Li, Liqun Sun
Summary: ln-WMS is a linear method for wavelength modulation spectroscopy that remains effective even for large absorbance, utilizing natural logarithms of transmitted intensity. By minimizing the first harmonic within the non-absorbing region, a seeking algorithm is used to determine the proper demodulation phase. The accuracy and efficiency of ln-WMS were confirmed in water vapor experiments, showcasing its potential for various applications.
CHINESE OPTICS LETTERS
(2021)
Article
Chemistry, Analytical
Yang Liu, Tao Wu, Qiang Wu, Weidong Chen, Chenwen Ye, Mengyu Wang, Xingdao He
Summary: The laser frequency-locked hollow waveguide (HWG) gas sensor demonstrated simultaneous measurements of three isotopologues with enhanced accuracy and precision under the frequency locking condition. This study showcases the high potential of a novel human breath diagnostic sensor for medical diagnostic with high accuracy, precision, and sensitivity.
ANALYTICAL CHEMISTRY
(2021)
Article
Instruments & Instrumentation
Wenke Liang, Guangfen Wei, Aixiang He, Hui Shen
Summary: A novel wavelength modulation spectroscopy (WMS) technique is proposed, which improves detection sensitivity by adding a triple frequency modulation current. Experimental results verify theoretical expectations, and this method can be applied for detection of other gas molecules.
INFRARED PHYSICS & TECHNOLOGY
(2021)
Article
Optics
Yihong Wang, Bin Zhou, Chang Liu
Summary: This paper presents a novel and rapid calibration-free wavelength modulation spectroscopy algorithm based on even-order harmonics. The algorithm simplifies the process of describing gas absorption spectra by using simple algebraic operations, eliminating the need for time-consuming simulations and line-shape fitting procedures. Experimental validation shows that the algorithm can calculate gas parameters at the millisecond level with a relative error of less than 4%.
Article
Engineering, Electrical & Electronic
Yuan Li, Yang Shen, Jiajun Tian, Qi Fu, Yong Yao
Summary: A novel multi-wavelength erbium-doped fiber laser with wavelength switchable capabilities is demonstrated based on PDL modulation and cascaded FBGs as wavelength comb filters. The PDL modulation balances the total loss and lasing gain, allowing for the creation of multiple lasing lines by adjusting PDLs in different wavelengths. The experiment successfully verifies the switching operation for single to four-wavelength laser outputs by adjusting the polarization controllers.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2021)
Article
Spectroscopy
Shaomin Li, Liqun Sun
Summary: In this paper, the technique of Natural Logarithm Wavelength Modulation Spectroscopy (ln-WMS) and the application of the eta-seeking algorithm were introduced. The effectiveness of the technique was validated through simulations and experimental measurement of water vapor. The linearity between the amplitudes of harmonics and concentration was established, even with large absorbance.
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
(2021)
Article
Spectroscopy
Shaomin Li, Liqun Sun
Summary: This paper proposes and demonstrates a method called Wavelength Modulation United Absorption Spectroscopy (WM-UAS) for measuring multi-component broadband absorbers, which requires the assistance of a probe substance exhibiting a series of narrow absorption profiles. The experiment validates the procedures and effectiveness of this method for measuring broadband absorbers.
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
(2021)
Article
Spectroscopy
Shaomin Li, Liqun Sun
Summary: WM-UAS is a new method for measuring broadband absorbers, utilizing wavelength modulation united absorption spectroscopy. The method requires the presence of well-resolved absorption peaks within the spectral envelope of the broadband absorber and has been successfully used to measure concentrations of gases like methanol.
SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
(2021)
Article
Chemistry, Multidisciplinary
Thomas Moore, Anthony J. Varni, Simon H. Pang, Sneha A. Akhade, Sichi Li, Du T. Nguyen, Joshuah K. Stolaroff
Summary: CO2-Binding organic liquids (CO(2)BOLs) are non-aqueous solvents that can reduce the energy consumption of carbon capture processes. These solvents exhibit surprising mass transfer behavior, with the flux of CO2 into CO(2)BOLs decreasing exponentially with increasing temperature. This phenomenon is primarily driven by a shift in reaction equilibrium, reducing the enhancement of CO2 flux by chemical reactions. First-principles surface renewal models accurately replicate the mass transfer data for CO2 absorption into different CO(2)BOLs, and density functional theory calculations identify structural modifications that could improve CO2 flux.
ENERGY & ENVIRONMENTAL SCIENCE
(2023)
Article
Engineering, Aerospace
Anil P. Nair, Daniel D. Lee, Daniel I. Pineda, Jason Kriesel, William A. Hargus Jr, John W. Bennewitz, Blaine Bigler, Stephen A. Danczyk, R. Mitchell Spearrin
Summary: High-speed laser absorption spectroscopy was used to measure thermodynamic properties in the annular exhaust of a methane-oxygen rotating detonation rocket engine. The test article consisted of a 76.2 mm diameter annulus with doublet impingement injection, and the analysis of CO absorption data revealed the evolution of gas properties under different test conditions.
AEROSPACE SCIENCE AND TECHNOLOGY
(2021)
Article
Optics
Wenke Liang, Minghao Wang, Guangfen Wei, Yonghan Fang, Zhenyang Zhao
Summary: A composite algorithm based on two-frequency modulation technology and empirical mode decomposition is proposed to suppress the noise of the fixed-point wavelength modulation spectroscopy system. Experiments show that two-frequency modulation can effectively suppress interference fringes, and the new composite method can significantly improve the denoising effect of two-frequency modulation.
OPTICS COMMUNICATIONS
(2023)
Article
Engineering, Electrical & Electronic
Fanghao Lu, Lijun Xu, Yigong Wu, Zhang Cao
Summary: A novel downsampling scheme was proposed to directly extract a precise and bias-immune absorption spectrum for dynamic gas temperatures. Multiple direct absorption profiles were generated by downsampling the absorbed wavelength-modulated laser intensity at equal phases in each modulation cycle. These profiles were employed to remove intensity biases from thermal radiations and obtain an entire absorption spectrum. Experimental results showed that the proposed method achieved higher precision and noise reduction compared to direct absorption spectroscopy and wavelength modulation spectroscopy methods. It also successfully evaluated the temporal variations of an acoustically excited flame.
IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT
(2023)
Article
Engineering, Electrical & Electronic
Renjie Li, Fei Li, Xin Lin, Xilong Yu
Summary: This article presents a new linear calibration-free wavelength modulation spectroscopy (LCF-WMS) technique for gas sensing. By combining the natural logarithms of the transmitted intensity and background signals, this technique eliminates the effects of the intensity, intensity modulation, and the modulation phase to obtain integrable harmonic signals along the line-of-sight and thus realize calibration-free measurements. To illustrate the validity of the LCF-WMS technique, it was applied to measurement of the water vapor concentration in air at ambient temperature. Because of its specific features of line-of-sight integrability and baseline independence, this method will be advantageous in absorption tomography and high-pressure applications.
MICROWAVE AND OPTICAL TECHNOLOGY LETTERS
(2023)
Article
Energy & Fuels
Chunyan Ma, Nan Wang, Nannan Ye, Xiaoyan Ji
Summary: The study compared the CO2 absorption capacity of three hybrid solvents based on [Bmim][OAc] and different cosolvents, with [Bmim][OAc]-DEPG250 showing the highest absorption capacity. The addition of DEPG250 significantly reduced the viscosity while maintaining comparable absorption capacity. Additionally, using [Bmim][OAc]-DEPG250 as a solvent resulted in a lower CO2 capture cost compared to aqueous amine solutions due to reduced utility costs.
Article
Optics
Yuriy S. Borisov, Azat M. Nizametdinov, Oleg Ivanov, Aleksey A. Chertoriyskiy
Summary: In this study, we demonstrate the feasibility of measuring reflection spectra of fiber Bragg gratings by tuning the wavelength of a commercially available laser diode. Two tuning methods, temperature and current tuning, are investigated. Both methods achieve a wavelength resolution of 2 pm, and it is shown that current tuning allows interrogation of fiber Bragg gratings at frequencies up to 100 kHz. Using the proposed methods, the shift of the reflection spectra of a fiber Bragg grating upon heating has been measured.
OPTICS AND LASER TECHNOLOGY
(2022)
Article
Thermodynamics
Anil P. Nair, Alex R. Keller, Nicolas Q. Minesi, Daniel I. Pineda, R. Mitchell Spearrin
Summary: This study presents an experimental approach to estimate the detonation cell size for liquid hypergolic propellants, such as monomethylhydrazine (MMH) and a MON-3 variant of nitrogen tetroxide (NTO), in a non-premixed combustor. The method correlates cell size with reactant fill height in an annular combustor geometry and utilizes high-speed videography to measure the number of waves and their speed under various detonation conditions. The validity of the method is demonstrated in both steady and transient conditions.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Thermodynamics
Vivek Boddapati, Alison M. Ferris, Ronald K. Hanson
Summary: A strategy based on Fourier transform infrared (FTIR) spectra was developed to estimate important combustion properties of jet fuels. By utilizing the infrared absorption features of hydrocarbon fuels, models were trained using gas-phase FTIR spectra to predict ignition delay time, net heat of combustion, and derived cetane number. The optimized models showed significant improvement in predictive performance compared to previous models, demonstrating the value of infrared spectral analysis as a pre-screening tool for accurate property estimation of jet fuels.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Thermodynamics
Shengkai Wang, Yiming Ding, Jingcheng Miao, Ronald K. Hanson
Summary: In this study, quantitative and high-accuracy measurements of multiple rate constants for the reaction kinetics of methanol pyrolysis were conducted using shock tube experiments. The reactions investigated include the thermal dissociation of methanol and its major fragments, as well as their H-abstraction by H and CH3 radicals. Laser absorption time-histories of CH2O, CO, and H2O were measured and analyzed, and the joint posterior distribution of their rate constants was determined using a Bayesian approach with FFCM-1 as the base mechanism. Various uncertainties in the measurements, such as non-ideal effects in the shock tube and uncertainties in the mixture composition and absorption model, were thoroughly analyzed. A comparative analysis using other reaction models was also briefly discussed.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Thermodynamics
Adam J. Susa, Ronald K. Hanson
Summary: This paper reports simultaneous schlieren and emission imaging through the side wall of a round shock tube for experimental autoignition studies. Autoignition experiments are conducted for non-dilute propane-oxygen-argon mixtures at elevated temperatures and pressures. The results show the importance of experimental design and provide valuable data for understanding autoignition processes.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Thermodynamics
Adam J. Susa, Lingzhi Zheng, Ronald K. Hanson
Summary: Laminar flame speed (SL) measurements of stoichiometric propane in an oxygen-argon oxidizer were conducted at different temperatures and pressures. The flame propagation was recorded using schlieren imaging, and a refined approach was used to account for flame distortion and residual gas motion. The experimental SL values showed a stronger temperature dependence than predicted by existing kinetic mechanisms. The present work represents a significant advancement in experimental capabilities for high-temperature flame speed measurements and provides valuable data for kinetic model tuning and validation.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Thermodynamics
Sergey F. Gimelshein, Jesse W. Streicher, Ajay Krish, Ronald K. Hanson, Ingrid J. Wysong
Summary: The direct simulation Monte Carlo method was used to model transient thermal and chemical relaxation behind reflected shock waves. The study found that the Bias reaction model is superior to other models in reproducing experimental results.
JOURNAL OF THERMOPHYSICS AND HEAT TRANSFER
(2023)
Article
Thermodynamics
Huaibo Chen, Weiqi Ji, Sean J. Cassady, Alison M. Ferris, Ronald K. Hanson, Sili Deng
Summary: In this study, maximum a posteriori estimation combined with a neural network response surface was used to optimize a propane mechanism against multispecies time-histories in a shock tube. The Bayesian approaches faced two problems: the effective independent-data number was not equal to the number of data points in a curve, and taking all points of a curve as targets could lead to different results. Three methods of calculating the likelihood function were used. The results showed that brute multiplication of all data points weakened the constraints from prior information and selecting critical points as targets yielded slightly better results. This study provides guidelines for modelers and experimentalists on the reasonable utilization of species time-histories and the importance of measurement error probability distribution and experiment design with emphasis on critical points.
PROCEEDINGS OF THE COMBUSTION INSTITUTE
(2023)
Article
Thermodynamics
Lingzhi Zheng, Zach Nygaard, Miguel Figueroa-Labastida, Adam J. Susa, Alison M. Ferris, Ronald K. Hanson
Summary: In this experiment, the laminar flame speeds of premixed propane in airgon were measured at atmospheric pressure. The experiment results were compared with a kinetic model, showing a maximum difference of 16%.
COMBUSTION AND FLAME
(2023)
Article
Thermodynamics
Rishav Choudhary, Sean Clees, Vivek Boddapati, Jiankun Shao, David F. Davidson, Ronald K. Hanson
Summary: The study investigated the impact of chain length on the time histories of key intermediate species during the first-stage ignition. Measurements were conducted on CO, CH2O, OH, and carbonyl compounds during the low temperature oxidation of n-octane and n-decane. Significant differences were observed between the measured and predicted ignition delay times and species formation rates. The measurements will contribute to the improvement of kinetic models and the development of rate rules for similar fuels. The study also revealed differences in the reactivity of n-octane and n-decane, indicating a correlation between species time histories, reactivity, and chain length.
COMBUSTION AND FLAME
(2023)
Article
Chemistry, Physical
Pujan Biswas, Rishav Choudhary, Ronald K. Hanson
Summary: We applied a multiwavelength speciation strategy to investigate the pyrolysis of n-pentane behind reflected shock waves. The measured species time histories were compared with four chemical kinetic models, but none of them were able to match the experimental data. Sensitivity analysis revealed that the unimolecular decomposition of n-pentane is the key reaction influencing the evolution of ethylene. By adjusting the rate coefficient of this reaction, a significant improvement in the prediction of species time histories was achieved. This is the first experimental determination of the rate coefficient of C5H12 -> nC3H7 + C2H5.
JOURNAL OF PHYSICAL CHEMISTRY A
(2023)
Article
Chemistry, Physical
Peter M. Finch, Zev N. Granowitz, Jesse W. Streicher, Ajay Krish, Christopher L. Strand, Ronald K. Hanson
Summary: We conducted shock-tube experiments using tunable diode laser absorption spectroscopy (TDLAS) to measure the collisional excitation of atomic nitrogen. The experiments were conducted behind reflected shocks at temperatures ranging from 8000 to 12000 K and pressures of 0.1 to 1.1 atm in mixtures of 1 or 2% molecular nitrogen (N2) in argon (Ar). The absorption from the transition between atomic nitrogen quantum states 4P to 4D was used to monitor the formation of electronically excited nitrogen.
JOURNAL OF PHYSICAL CHEMISTRY A
(2023)
Correction
Engineering, Aerospace
Anil P. Nair, Alex R. Keller, David S. Morrow, Alexander B. Lima, R. Mitchell Spearrin, Daniel I. Pineda
JOURNAL OF SPACECRAFT AND ROCKETS
(2023)
Article
Mechanics
Jesse W. Streicher, Ajay Krish, Ronald K. Hanson
Summary: The fast decomposition of nitrous oxide (N2O) into molecular nitrogen (N-2) and atomic oxygen (O) was studied to probe the N-2 + O and NO + O Zeldovich reactions. Experiments were conducted at temperatures ranging from 2000 to 6800 K and pressures ranging from 0.04 to 1.67 atm, with 1% and 5% N2O diluted in argon (Ar) or N-2. Infrared and ultraviolet laser absorption diagnostic systems were used to measure the concentrations of N2O and NO, and the results were used to infer the reaction rates.
Article
Thermodynamics
Ponnuthurai Gokulakrishnan, Jiankun Shao, Michael S. Klassen, David F. Davidson, Ronald K. Hanson
Summary: This study investigates the formation and effects of NOx from ammonia impurities in high-pressure supercritical CO2 oxy-combustion conditions. Computational and experimental analyses show that the NH radical and CO2 reaction determines the rate of NOx formation. The sCO2 oxy-combustion significantly reduces NOx formation compared to traditional gas turbine conditions. The presence of NO in the recycled-CO2 promotes ignition and acts as a chemical catalyst to increase the combustion radical pool.
APPLICATIONS IN ENERGY AND COMBUSTION SCIENCE
(2023)
Article
Energy & Fuels
Lingzhi Zheng, Miguel Figueroa-Labastida, Zach Nygaard, Alison M. Ferris, Ronald K. Hanson
Summary: The laminar flame speeds of ethanol, iso-octane, and their blends were measured using a shock tube and a laser-spark ignition system. The results provide valuable data for studying high-temperature flame speeds and improving kinetic models. The correlation between fuel/air flame speeds and unburned-gas temperature was determined, and key controlling reactions for ethanol flame speeds were identified.
