Real-gas properties of n-alkanes, O2, N2, H2O, CO, CO2, and H2 for diesel engine operation conditions

The objective of the research outlined in this paper was to develop the analytical approximations for calculating real-gas properties (p-v-T data, thermodynamic functions: internal energy, enthalpy, and entropy, and specific heats) of vapor-phase n-alkanes from C₁ (methane) to C₁₄ (normal tetradecane), O₂, N₂, H₂O, CO, CO₂, and H₂ within the range of pressure 0.05 MPa ≤ p ≤ 20 MPa and temperature 280 K ≤ T ≤ 3000 K aimed for implementation into computational fluid dynamics (CFD)-codes simulating the operation process in modern Diesel engines. The analytical approximations have been developed based on available literature data and on the new equation of state for moderately dense gases. The approximations reported are rather simple and therefore can be used directly in CFD codes. Approximations for mixing rules are also provided.     

Simultaneous determination of the ground level abundances of N2O,CO2, CO and H2O

The AFCRL atmospheric line-parameter listing has been used with a non-linear, least-squares method of analysis to obtain the abundances of N₂O and CO in a sample of ground level air with a precision of about 1%. Absorption coefficients calculated for N₂O agree satisfactory with laboratory measurements but an error of 0.0267 cm^-1 in the listed position of an H₂O line at 2205.250 cm^-1 has been corrected and errors in the positions and intensities of CO₂ lines between 2230 and 2250 cm^-1 have been observed.     

FTIR-spectra of solid O2, N2 and CO

FTIR measurements of thin films of N₂, O₂ and CO at about 20 K contain a line due to the allowed or induced fundamental transition and a broad structure shifted to higher frequencies. This phonon sideband is explainable by coupling of lattice vibrations to the molecular fundamental vibration, and mirrors the weighted one phonon density-of-states. This IR-derived density-of-states can be compared with those from other experimental studies (neutron scattering, Raman) and from theoretical models.     

Ionization energies of the N2, CO,CO2, N2O,C2H2 and SiH4 molecules calculated by universal model potential

Acta physica Academiae Scientiarum Hungaricae - A modified XαSW method with universal potential (MXαSWU) was used to calculate ionization energies of the N2, CO, CO2, N2O, C2H2 and SiH4...     

Multiline laser probing of CO:He, CO:N2, and CO:O2 active media in a wide-aperture pulsed amplifier

Multiline laser probing was applied for the diagnostics of the active medium of a wide-aperture carbon monoxide laser amplifier. The temporal behavior of the small-signal gain in the active medium of a pulsed electron-beam sustained discharge CO laser amplifier was studied with a specially designed probe CO laser in a wide range of ro-vibrational spectral lines (from V = 5 up to V = 31). The results were analyzed in order to reconstruct the temporal behavior of gas temperature and vibrational populations in CO-containing gas mixtures, CO:He and CO:N₂, and oxygen-rich CO: O₂ mixtures. __________ Translated from Preprint No. 13 of the P. N. Lebedev Physical Institute, Moscow (2005).     

CO2,X (X=CO2, N2, He,NH3) pressure broadening and shift at 10 μm by using a mode tunable RF CO2 laser

Summary By using a mode tunable CO₂ radiofrequency excited laser we have measured the pressure broadening and the shift of many CO₂ laser lines perturbed by different gases (CO₂, N₂, He, NH₃). While the broadening data agree with the previous work results, this technique allows a more accurate shift measurement. In particular the broadening and shift coefficients due to ammonia are measured for the first time.

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Riassunto Mediante un laser CO₂ alimentato a radiofrequenza ed accordabile in modo su singola riga 510 MHz noi abbiamo misurato sia l’allargamento che lo spostamento per pressione delle righe delle transizioni laser dovuti a differenti perturbatori X (X=CO₂, NH₃, N₂, He). I dati di allargamento confermano le misure precedenti mentre quelli di spostamento sono in parziale disaccordo. I dati per il sistema CO₂, X (X=NH₃) sono riportati per la prima volta.

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Резюме Используя CO₂ лазер с радиочастотным возбуждением, мы измеряем уширение под действием давления и сдвиг CO₂-лазерных линий, возмущенных различными газами (CO₂, N₂, He, NH₃). Данные по уширению согласуются с результатами предыдущих работ. Однако используемая техника позволяет провести более точные измерения сдвига. В частности, впервые были измерены коэффициенты уширения и сдвига, обусловленные аммиаком.

     

Infrared radiation modeling of NO,OH, CO,H2O,and CO2 for emissivity/radiance prediction at high temperature

In the present study, infrared radiation modeling of NO, OH, CO, H₂O, and CO₂ molecules was devised based on a line-by-line method by utilizing a structured radiation analysis package, SPRADIAN07, coupled with up-to-date spectroscopic parameters and recent high-resolution radiation databases. An infrared calculation module was newly implemented in SPRADIAN07 for simulating the emissivity/radiance of NO and OH. The line positions of NO and OH molecules were determined by diagonalizing the Hamiltonian matrices of each molecule. The Einstein coefficients were obtained from either radiation databases or available calculated temperature-related line intensities. H₂O, CO₂, and CO were also modeled based on the high-resolution radiation databases, HITEMP2010 and CDSD-4000. When the line-by-line calculations were performed using the radiation databases, a parallel computing technique based on PC clusters was adopted for fast and efficient evaluation. The line-by-line model devised in the present study was validated by comparing the results with existing measurements. The simulations with room air absorption composed of H₂O and CO₂ were also carried out. The spectra taken from a plasma torch and those from a rocket plume were calculated by utilizing the present radiation model. It was shown that the calculated spectra are in good agreement with observed ones.     

Foreign gas broadening of difluoromethane by N2, O2 and CO2

The linewidth parameters of difluoromethane broadened by N₂, O₂, and CO₂ have been measured at microwave frequencies and are compared with calculated values for dipole-quadrupole interactions by using the Murphy-Boggs theory. The observed linewidths yield reasonable values of molecular quadrupole moments.     

CO2 laser heterodyne rangefinders,velocimeters and radars

A review of principles and design features emphasizes how the choice of transmitter waveform is affected both by the intended application and by the ever-advancing capabilities of lasers, modulators and receiver signal-processing systems. Achievements in application areas are surveyed including the work at RSRE on rangefinders/velocimeters and on Doppler anemometers.     

High-pressure,high-repetition-rate RF CO2 laser

Summary In this work we report the physical properties of a radiofrequency supplied waveguide CO₂ laser operating with different standard mixtures at high pressures up to 1.5 bar, with about 10% electrical efficiency. We describe some problems to obtain a complete RF matching in the discharge and we analyse the conditions for a better efficiency, gain and peak power in different mixtures, both to obtain a larger mode tuning and to eliminate the he contents so that the laser running costs are largely reduced. Work partially supported by the Progetto Finalizzato Optoelettronica of the Italian National Research Council (CNR). The authors of this paper have agreed to not receive the proofs for correction.     

Adsorption and solution of H2, D2, N2, O2 and CO by (100) Ta

Sticking coefficients, saturation densities, and solution rates of gases on (100) Ta are obtained by comparing with results on (100) W using Auger electron spectroscopy and flash desorption. Hydrogen has a lower sticking coefficient on (100) Ta than on polycrystalline Ta, but solution occurs readily even at 78°K. Differences between H₂ and D₂ are observed for both adsorption and solution. Nitrogen is confined to the surface of Ta for T < ≈500°K, and adsorbed nitrogen dissolves with an activation energy of ≈2.5 kcal mole^?1 upon heating to higher temperatures. The saturation density of O₂ at 300° K is approximately twice that on (100) W. The first monolayer dissolves at ≈500°K but the second dissolves or desorbs only at much higher temperatures. Carbon monoxide adsorbs without solution of either species at 300°K. At ≈500°K carbon dissolves completely leaving oxygen which desorbs at much higher temperature.     

Information System for Calculating the Spectral Characteristics of Hot CO,CO2, and H2O Gases (Hotgas 2.0)

The information system HOTGAS 2.0 is described which allows the parameters of vibrational-rotational lines of CO, CO₂, and H₂O molecules to be calculated in the spectral range 0–10000 cm^–1 and in the temperature range 250–3000 K. A user-friendly system interface allows the data to be displayed in text and graphic formats and has all the advantages of programs written in the Windows 95 environment. The system HOTGAS 2.0 can be used to calculate the absorption coefficients of individual gases and gaseous mixtures for the optically thin layer model.     

Vibrationally inelastic scattering of H∼ ions from H2, N2, O2 and CO2

State-resolved measurements are presented for vibrational excitation of H₂, N₂, O₂ and CO₂ by H^? impact in the collision energy rangeE _cm=20–180 eV and for scattering in the forward direction (0±0.5°). The data obtained from the measurements are the relative intensities and differential cross sections for vibrational excitation up toν′=4, the transition probabilitiesP _0→ν′ and the vibrational energy transferΔE _vib. For the systems H^?-H₂, N₂, O₂ the vibrational inelasticity increases in the order H₂-N₂-O₂. The mechanism for vibrational excitation in these systems is due to transient charge transfer from the H^? ion into antibonding orbitals of the target molecule which provides a bond stretching force during the collision. For H₂ and N₂, the results are compared with corresponding measurements for H⁺ scattering where the interaction mechanism is quite different. In the case of CO₂, vibrational excitation in forward scattering is caused primarily by the long-range dipole interaction. The spectra are very similar for H^?-CO₂ and H⁺-CO₂. Finer details are attributed to the influence of transient charge transfer and valence interactions.     

V2CO2MXene从CO2/N2混合气体中选择性吸附CO2的第一性原理计算

二氧化碳作为温室气体中最重要的组成部分,其含量的变化将直接影响全球气候变化,在燃烧后气体中选择性捕获CO₂,对减缓因CO₂浓度过高引发的环境问题具有十分重要的意义.本文采用第一性原理计算的方法,研究了V₂CO₂ MXene材料对CO₂的选择性吸附性能.首先研究了不同官能团V₂CT_X MXene材料的结构和性质,发现V₂CO₂具有良好的稳定性.后研究了V₂CO₂对CO₂的吸附行为,结果表明,当CO₂被水平吸附时,V₂CO₂对CO₂气体分子的吸附能力较强且均满足在高性能吸附剂表面吸附CO₂的理想值(-0.42 eV-0.82 eV),可以适用于探测/捕获CO₂气体分子.此外,进一步研究了相同条件下V<...     

UV absorption cross section of the molecules O2, NO,N2O,CO2, H2O,and NO2

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 52, No. 3, pp. 455–465, March, 1990.     

The absorption cross sections of N2, O2, CO,NO, CO2, N2O,CH4, C2H4, C2H6 and C4H10 from 180 to 700Å

The absorption cross sections of N₂, O₂, CO, NO, CO₂, N₂O, CH₄, C₂H₄, C₂H₆, C₄H₁₀ have been measured photoelectrically in the 180–700 Å region using synchrotron radiation. The absorption cross sections in the region λ ≥ 500 Å was found to be structureless and to increase monotonically with wavelength for all gases. The positions of the structure observed in the 520–720 Å region for N₂, O₂, CO₂ and N₂O are consistent with the various Rydberg series reported by previous authors.