Triatomic Gas Research Articles

The Heat Capacity of Triatomic Gases: An Analytical Approach

The Heat Capacity of Triatomic Gases: An Analytical Approach

Heat Transfer Mechanisms in Arcs of Various Gases at Atmospheric Pressure

This work expands findings about the dominant heat transfer mechanisms in argon and helium arcs at atmospheric pressure for monoatomic (Ar, He, 50% Ar–50% He), diatomic (air, {hbox{N}}_{2}, {hbox{O}}_{2}, {hbox{F}}_{2}, {hbox{Cl}}_{2}), and triatomic ({hbox{CO}}_{2}) gases. The objective is to understand the dominant mechanisms in atmospheric plasmas through validated numerical modeling for GTAW welding process. Arcs of all gases have lengths of 10 mm and 200 A current. Five heat transfer mechanisms are considered: Joule heating, convection, radiation, conduction, and Thomson effect. Results indicate that the general structure of the arcs and dominant mechanisms are qualitatively similar for all gases; sizes change depending on the gas. The dominant energy input near the cathode is Joule heating, while that near the anode is convection. The dominant energy output always follows the same sequence: Thomson effect next to the cathode followed by convection, radiation in the arc column, and conduction near the anode. Joule heating is the most significant in Ar, while in He, it has the lowest significance. This is due to differences in electric conductivity of He (higher up to 21,000 K and lower beyond 21,000 K than other gases) and high viscosity of He, which creates a small Joule heating versus a large convection region. He transfers the most heat towards the anode by convection while {hbox{N}}_{2} has the lowest; due to the high enthalpy and viscosity of He compared to {hbox{N}}_{2}. Finally, Ar has the most significant radiative emission and He the smallest due to their net emission coefficient.

Energy saving analysis and thermal performance evaluation of a hydrogen-enriched natural gas-fired condensing boiler

Hydrogen-enriched natural gas (HENG) has attracted widespread attention due to its lower pollutant emissions and industrial decarbonization in the past decades. HENG combustion boosts the water content in the flue gas, which is highly favorable for condensing boilers to recover additional latent heat. The energy saving and thermal performance of a condensing boiler burning HENG were evaluated at a constant heat load of 2.8 MW in this study. The variations in combustion products and boiler efficiency were investigated based on the material balance and energy conservation. The heat transfer calculations were employed to evaluate the thermal performance of boiler heating surfaces. The energy recovery performance of the condenser was assessed via a thermal design method. Results show that H2 enrichment enhances the radiation intensity of the flame due to the incremental triatomic gases with higher emissivity in the furnace. The heat absorption ratio increases with H2 enrichment in the radiative heating surface, while it shows a reverse tendency in the convective heating surface. The condensing boiler efficiency based on lower heating value increases from 101.83% to 110.60%, the total heat transfer rate of the condenser increases from 2.77 × 105 W to 4.61 × 105 W, and the total area required decreases from 46.45 m2 to 42.16 m2, as the H2 enriches from 0 to 100% under the exhaust flue gas temperature of 318 K. Although the amount of recoverable heat in the exhaust flue gas increases considerably after H2 blending, the original condenser with natural gas as the designed fuel could meet the requirements of the heat recovery for HENG without increasing the extra heating surface. When the H2 fraction is enriched from 0 to 100%, CO2 emission intensity drops from 6.05 × 10−8 kg J−1 to 0. This work may offer some theoretical references for the application and generalization of HENG condensing boilers.

Hybrid G/BN@2H-MoS2 Nanomaterial Composites: Structural, Electronic and Molecular Adsorption Properties.

Hybrid structures often possess superior properties to those of their component materials. This arises from changes in the structural or physical properties of the new materials. Here, we investigate the structural, electronic, and gas-adsorption properties of hybrid structures made from graphene/hexagonal boron nitride and 2H-molybdenum disulfide (G/BN@MoS2) monolayers. We consider hybrid systems in which the G/BN patch is at the Mo plane (model I) and the S plane (model II). We find that the implanted hexagon of G or BN in MoS2 alters its electronic properties: G@MoS2 (I,II) are metallic, while BN@MoS2 (I) is an n-type conducting and BN@MoS2 (II) is semiconducting. We study the molecular adsorption of some diatomic gases (H2, OH, N2, NO, CO), triatomic gases (CO2, NO2, H2S, SO2), and polyatomic gases (COOH, CH4, and NH3) on our hybrid structures while considering multiple initial adsorption sites. Our results suggest that the hybrid systems may be suitable materials for some applications: G@MOS2 (I) for oxygen reduction reactions, BN@MoS2 (I,II) for NH3-based hydrogen production, and G@MoS2 (I) and BN@MoS2 (I,II) for filtration of No, Co, SO2, H2S, and NO2.

Incineration problems for the heat supply using garbage from the overproduction of fast fashion clothing

Today, one of the sources of energy supply is waste incineration. One of the sources of combustible waste is overproduction and stimulation of demand for clothing. The new concept of "fast fashion" is to limit the cost of clothing indefinitely by minimizing the cost of raw materials, wages, working conditions, neglect of basic safety rules, etc., and on the other hand - to stimulate predatory demand for clothing through psychological impact on young people through advertising, suggestion consumer "standards" of life such as "every event is a different image", propaganda of shopaholism, etc. According to research results, burning cotton clothes for heating is possible. However, this produces a significant amount of triatomic (greenhouse) gases, in particular carbon dioxide 102.84 kg / GJ. In terms of carbon dioxide emissions per unit of energy (emission index), cotton fabric is ahead of all fossil fuels, even coal - 93.74 kg / GJ. Thus, excessive production of garbage through "fast fashion" has more negative consequences for the environment than benefits for heat supply. Thus, the results confirm the 12th goal of sustainable development - "responsible consumption and production". At the same time, the priority is to reduce the amount of waste production. The main stimulus for "fast fashion" is the predatory accumulation of capital by producers. This can be overcome only by reassessing people's values. In particular, it is necessary to form the attitude to money not as an ultimate goal, but as a payment instrument to achieve certain other life goals. In this case, predatory accumulation for the sake of accumulation becomes meaningless. After all, one's own well-being, children's well-being and confidence in the future are impossible in the conditions of low quality of the environment and in anticipation of an ecological catastrophe. This work was done in support of the international campaign "Fashion Revolution" for the global fashion industry, which preserves and restores the environment and values people.

Measurement of Variation of Momentum Accommodation Coefficients with Molecular Mass and Structure

A disk spindown experiment allows measurement of tangential momentum accommodation coefficients of different gases and material combinations in a consistent manner. Aluminum is tested for a range of gases, including monoatomic, diatomic, and triatomic gases. The results confirm previous experimental results that show a reduction in tangential momentum accommodation coefficients with increasing molecular masses of gases. In addition, the results reveal a previously unreported phenomenon: that the tangential momentum accommodation coefficient is also a function of the molecular structure of gases.

Method for determining blast furnace tuyere zone blackness degree on pulverized coal fuel injection

Pulverized coal fuel (PCF) supply is one of the modern methods of improving the cast iron production technology in blast furnaces (BF). It has a significant effect on the heat exchange in the tuyere zone (TZ). The known method of radiant heat transfer calculation in TZ accounts only for the ash particle effect on the TZ blackness degree. The aim of this work is to develop a method for determining TZ blackness degree and to investigate the effect of different factors on this value. The work was based on the elements of the proven method of calculating heat exchange in boiler furnaces. Parametric sensitivity was investigated by alternately simulating an error in each of the input values and determining its effect on the sought value. By analysing the processes, the authors have derived dependences for obtaining the concentration of ash particles and triatomic gases and determined the degrees of TZ blackness by Bouguer’s law simultaneously taking into account the radiation of the burning coke and ash particles, and triatomic gases. It has been established that an increase in the PCF consumption from 0 to 250 kg/t of pig iron changes the TZ blackness degree from 0,067 to 0,243; and a 1 % increase in the pressure, concentration of triatomic gases, ray effective length, TZ temperature and ash particle size changes the TZ blackness by 0,714 %, 0,151 %, 0,72 %, –1,557 % and –0,176 %, respectively. The calculations have shown that the effects of coke particles, triatomic gases and ash particles on the sought value are approximately equal. In contrast, when the conventional method is applied, it results in an approximately 2-time underestimation of the values, while even for evaluation calculations, the maximum permissible error is 10–15 %. The developed method accounting for all factors has the maximum error of 5 %. It is important for designing tuyeres and TZ refrigerators.

Density functional theory investigation of the interactions between the buckled stanene nanosheet and XO2 gases (X = N, S, C)

Based on the density functional theory calculations, we examined the adsorption behaviors of triatomic gas molecules (such as NO2, SO2 and CO2) on the buckled stanene nanosheets. By studying the interactions between stanene and XO2 gases (X = N, S and C), we exploited the gas sensing capabilities of innovative stanene based sensors. We investigated the electronic properties of the studied systems in terms of the density of states, Mulliken charges and charge density difference calculations. The results indicated that the adsorption of gas molecules on the doped stanene nanosheets is more favorable in energy than that on the pristine ones, implying that the doped stanene acts as an appropriate candidate for sensing materials. The electronic density increases at the middle of the newly formed bonds between stanene and gas molecule. Charge density difference calculations indicated that both NO2 and SO2 gases exhibit acceptor characteristics, as evidenced by the charge accumulation on the adsorbed gas molecules. The strong PDOS overlaps between the N, O atoms in the NO2 molecule and the Sn atoms of the stanene nanosheet, indicated the formation of chemical bonds between them. Also, the PDOS spectra of the O atoms of SO2 molecule and Sn atoms show significant overlaps, indicating the formation of a double contacting point for SO2 on the stanene. The bad structures diagrams of the gas molecule adsorbed stanene nanosheets show that the VBM and CBM are slightly altered upon gas adsorption. Our theoretical findings show that stanene holds a great potential to be utilized as highly efficient sensor device for detection of triatomic gases like NO2, SO2 and CO2 in the atmosphere.

Volcanic gas composition, metal dispersion and deposition during explosive volcanic eruptions on the Moon

The transport of metals in volcanic gases on the Moon differs greatly from their transport on the Earth because metal speciation depends largely on gas composition, temperature, pressure and oxidation state. We present a new thermochemical model for the major and trace element composition of lunar volcanic gas during pyroclastic eruptions of picritic magmas calculated at 200–1500°C and over 10−9–103bar. Using published volatile component concentrations in picritic lunar glasses, we have calculated the speciation of major elements (H, O, C, Cl, S and F) in the coexisting volcanic gas as the eruption proceeds. The most abundant gases are CO, H2, H2S, COS and S2, with a transition from predominantly triatomic gases to diatomic gases with increasing temperatures and decreasing pressures. Hydrogen occurs as H2, H2S, H2S2, HCl, and HF, with H2 making up 0.5–0.8mol fractions of the total H. Water (H2O) concentrations are at trace levels, which implies that H-species other than H2O need to be considered in lunar melts and estimates of the bulk lunar composition. The Cl and S contents of the gas control metal chloride gas species, and sulfide gas and precipitated solid species. We calculate the speciation of trace metals (Zn, Ga, Cu, Pb, Ni, Fe) in the gas phase, and also the pressure and temperature conditions at which solids form from the gas. During initial stages of the eruption, elemental gases are the dominant metal species. As the gas loses heat, chloride and sulfide species become more abundant. Our chemical speciation model is applied to a lunar pyroclastic eruption model with isentropic gas decompression. The relative abundances of the deposited metal-bearing solids with distance from the vent are predicted for slow cooling rates (<5°C/s). Close to a volcanic vent we predict native metals are deposited, whereas metal sulfides dominate with increasing distance from the vent. Finally, the lunar gas speciation model is compared with the speciation of a H2O-, CO2- and Cl-rich volcanic gas from Erta Ale volcano (Ethiopia) as an analogy for more oxidized planetary eruptions. In the terrestrial Cl-rich gas the metals are predominantly transported as chlorides, as opposed to metallic vapors and sulfides in the lunar gas. Due to the presence of Cl-species, metal transport is more efficient in the volcanic gas from Erta Ale compared to the Moon.

Influence of the "Self-Radiation" of Combustion Products on the Intensity of Evaporation of an Inhomogeneous Water Droplet in the Flame

The processes of heat transfer during the heating, evaporation, and boiling of an inhomogeneous (with a solid inclusion) droplet of a liquid (water) in a high-temperature (800–1500 K) gas medium have been modeled numerically. The inclusion (carbonaceous particle) in the shape of a disk of height and diameter 2 mm has been considered. The volume of the water enveloping the inclusion ranged within 5–20 μL. It has been shown that the ″self-radiation″ of triatomic gases in combustion products (using commercial alcohol as an example) significantly intensifies (compared to the air heated to the same temperatures) the heating of the inhomogeneous liquid droplet. A comparative analysis of the influence of the temperature of the gas medium and of the thickness in the liquid film enveloping the inclusion on the basic characteristic of the process under study, i.e., the time of existence (complete evaporation) of the droplet, has been made. The reliability of the results of theoretical investigations and the legitimacy of the conclusions drawn have been assessed experimentally.

Influence of inherent moisture on the ignition and combustion of wet Victorian brown coal in air-firing and oxy-fuel modes: Part 1: The volatile ignition and flame propagation

This study for the first time reported the volatile ignition and oxidation for wet Victorian brown coal in both air-firing and oxy-fuel modes. The aim is to quantitatively understand the evaporation of inherent moisture and its overlapping with the subsequent volatile ignition and oxidation steps during pulverised coal combustion. A wet Victorian brown coal sample with the moisture content up to 30wt.% and a size range of 63–104μm has been tested. Its ignition, volatile flame propagation and char oxidation have been diagnosed optically in a laboratory-scale flat-flame burner reactor (FFBR) coupled with a high-speed camera. 1-D modelling was also conducted to predict coal ignition based on the classic coal drying theory and coal devolatilisation rate. As has been confirmed, the release of moisture on the initial drying stage is incomplete prior to the subsequent volatile ignition. The fraction of moisture released upon drying only accounted for 10% of its original amount in wet brown coal prior to ignition. This is due to a firm residence of the moisture within coal capillaries, and a rapid heat feedback from hot gas to the dried particle surface that was ignited instantaneously prior to the release of the remaining moisture. The unevaporated moisture was observed to be released with the volatiles together to form a thick cloud layer in the vicinity of the coal particle, thereby enlarging the sizes of the volatile flame remarkably, which are approximately twice the size of the dried coal flame. However, the intensity of the wet coal flame was much weaker than dried coal, due to the dilution effect of the inherent moisture on the volatile cloud. In the oxy-fuel combustion mode, the inherent moisture interrelated with CO2, a tri-atomic gas with a larger specific heat capacity than N2 to significantly delay the ignition of the wet coal particle and its flame intensity and propagation velocity.

Theoretical study on the microhydration of atmospherically important carbonyl sulfide in its neutral and anionic forms: bridging the gap between the bulk and finite size microhydrated cluster.

Carbonyl sulfide (OCS) is the most abundant and stable sulfur-containing triatomic gas present in the atmosphere that plays an important role in aerosol formation. Structure, energetics, and photoelectron spectral properties of the microhydrated OCS in its neutral and anionic forms have been studied by using the BP86, B3LYP, and MP2 methods. OCS is linear in the neutral state but bent in the anionic state. Water binds with the OCS through a single hydrogen bond (O-H···O) in the OCS-(H2O)n [n = 1-6], whereas binding of OCS(-) with water takes place through single as well as double hydrogen bonds (O-H···S and O-H···O). Energy decomposition analysis shows that electrostatic and exchange energies are the main contributors to the stabilization energy of the microhydrated OCS and OCS(-) clusters. Detachment as well as solvation energies are calculated with different levels of theory and compared with the existing experimental values. Finally, an analytical expression has been used to obtain the bulk value of the detachment and solvation energies from the existing information on the finite size clusters. The present study reveals that hydration increases the detachment energy of the OCS(-) by 3.2 eV. In the absence of experimental bulk values of the detachment and solvation energies for this system, the values obtained by the solvent-number-dependent theoretical expression will definitely reduce this gap and may be used for the modeling of the OCS in the atmosphere.

A qualitative study of the retention and release of volatile gases in JSC-1A lunar soil simulant at room temperature under ultrahigh vacuum (UHV) conditions

We conducted a qualitative study to simulate the flux of volatile gases expected to occur at the lunar surface due to cometary impact or lunar outgassing events. A small sample cell containing 8.8g of JSC-1A lunar soil simulant in a vacuum system with a base pressure of 1.5×10−8Torr was exposed to various gases using dynamic pressure dosing at room temperature to observe any retention of those gases as a function of the exposure times, temperatures and pressures used. Gases included pure argon, a five-component gas mixture (H2, He, Ne, N2, Ar), a simulated Mars atmospheric mixture (CO2, N2, Ar, CO, O2), and a simulated Titan mixture (N2, CH4). Results at exposure pressures of approximately 1.5×10−8Torr above background showed no observable retention of rare gases, slight retention of molecular gases, but surface retention of the triatomic gas CO2 occurred at room temperature with a time to reach equilibrium of greater than 10min, which was an unanticipated result. Despite several bakeouts and months under ultrahigh vacuum (UHV) conditions, trace levels of atmospheric gases continued to evolve from the simulant. Mechanical and optical probing of the simulant surface increased this latent gas evolution, particularly for CO2 and CO, with some evidence also for the release of CH4. We assert our results are, by analogy, applicable to protocols and instrumentation needed for conducting analytical chemistry aboard future landed lunar missions.

The climate system

An overview of what we know about the climate of the planet Earth up to 5.5 millions of years from now is presented first, with the air temperature in proximity to the surface as the main, and more feasible, parameter to be followed. The behavior of this parameter exhibits a distinct periodicity with more internal fluctuations. This overview prompts us to a description of the physical basis of the climate system, capable of explaining such fluctuations. The system is the star-planet, initially described as a lamp-billiard ball simple system. Astronomical causes affect the distance lamp-billiard ball (star-planet) and the ball (Earth) rotation axis orientation, while astronomical causes affect the intensity of radiation emitted from the lamp (Sun). The complication introduced by the atmosphere is then explained, essentially through the triatomic gas molecules, aerosol and clouds. Atmospheric composition affects incoming solar radiation and outgoing infrared one. The compartments relevant for climate definition are examined: lithosphere, hydrosphere, cryosphere, biosphere including vegetation and humans. However due to space limitations the interactions between the different compartments are not treated here and we restrict ourselves to the treatment of the atmosphere.

Titanium Dioxide Nanoparticle Surface Reactivity with Atmospheric Gases, CO2, SO2, and NO2: Roles of Surface Hydroxyl Groups and Adsorbed Water in the Formation and Stability of Adsorbed Products

The reactivity of O–H groups on titanium dioxide nanoparticle surfaces with gas-phase carbon dioxide, sulfur dioxide, and nitrogen dioxide is compared. Carbon dioxide, sulfur dioxide, and nitrogen dioxide react with ca. 5, 50, and nearly 100%, respectively, of all hydroxyl groups on the surface at 298 K. As shown here, the surface reactivity of O–H groups with these three triatomic gases differs considerably due to different reaction mechanisms for adsorption and surface chemistry. In addition to investigating O–H group reactivity, the role of adsorbed water in the stability of different surface species that form from adsorption of carbon dioxide, nitrogen dioxide, and sulfur dioxide on hydroxylated TiO2 nanoparticles is probed as a function of relative humidity as is quantitative measurements of water uptake on TiO2 nanoparticles before and after surface reaction. These water uptake studies provide insights into the stability of adsorbed species on oxide surfaces under atmospherically relevant conditions as well as changes in particle hygroscopicity and adsorbed water dynamics following reaction with these three atmospheric gases.

The Hall conductivity of graphene

Sensitivity of the Hall conductivity of graphene plane to gas molecule adsorption is investigated within the coherent potential approximation for the tight-binding model Hamiltonian. The results show that the Hall conductivity of system have a limit change when finite triatomic and tetratomic gas molecules adsorb and act as acceptors or donors.

Density functional studies of small gases adsorbed on the ZnO sodalite-like cage and its adsorption abilities

The geometry optimizations of ZnO sodalite-like cage (ZnOSL), Zn12O12 cluster and its adsorption configuration with diatomic (H2, N2, O2, CO, NO), triatomic (CO2, N2O, NO2, H2O, SO2) and tetraatomic (NH3) gases were carried out using density functional theory method. Adsorption energies of these gases on ZnOSL were obtained at the B3LYP/Lanl2DZ level of theory. The strongest adsorption energies of diatomic and triatomic gases on ZnOSL at ML=0.082 are ΔEads(O2)=−14.09 and ΔEads(SO2)=−35.06kcal/mol, respectively. The adsorption energy of ammonia adsorbed on ZnOSL at ML=0.082 is ΔEads(NH3)=−25.41kcal/mol. Energy gaps and density of states plots for ZnOSL and their gases adsorption configurations are reported. All the adsorption results computed by the B3LYP/Lanl2DZ method were validated by comparison with their corresponding results computed by the B97D/Lanl2DZ method.

A method for calculating the absorption properties of triatomic gases

Formulas are proposed for the steam and carbon dioxide absorption coefficients, which are widely used in calculations of radiant heat transfer in industrial ovens and furnaces and containing empirical correction multipliers approximated over the beam length by logarithmic polynomials the coefficients of which are interpolated with respect to gas temperature. Generally, the error in the steam and carbon dioxide absorption capacities calculated using these formulas does not exceed 3%, which is quite acceptable in engineering calculations of radiant heat transfer. It is shown that the absorption capacity of a mixture of steam and carbon dioxide calculated using the exponential function of the total absorption coefficient does need correction for mutual absorption of beam energy by the components of medium.

Gas adsorption effects on the electrical conductivity of semiconducting carbon nanotubes

We study the effect of diatomic (X 2) and triatomic (XY 2) gas molecule adsorption on the electrical conductivity of (8,0), (10,0) and (14,0) semiconducting zigzag single-walled carbon nanotubes. We use Green's function method and coherent potential approximation. We find that the electrical conductivity of semiconducting carbon nanotubes is sensitive to the adsorption of these gases, when X 2 and XY 2 are identified as charge acceptors. While X 2 and XY 2 molecules adsorb weakly on nanotubes and act as charge donors, the electrical conductivity of the nanotubes shows no noticeable change.

Nitrogen dioxide solubility and permeation in lipid membranes

Nitrogen dioxide (NO2) is an important oxidant molecule in biology that is produced by several biological processes, and it is also an important air pollutant. It can oxidize proteins and lipids with important consequences on their biological functions. Despite its relevance, the interaction of NO2 with the cell barrier, the lipid membrane, is poorly understood. For instance, can lipid membranes limit NO2 diffusion? To estimate the permeability of lipid membranes to NO2 it is necessary to learn more about its solubility in the lipid phase. However, experimental data on NO2 solubility is very limited. To improve our knowledge on this matter, we used a mixed approach consisting in calculating the solubility of NO2 and related diatomic and triatomic gases (NO, O2, CO2, etc.) in different solvents using quantum calculations and Tomasi’s Polarizable Continuum Model and validating and correcting these results using experimental data available for the related gases. This approach led to an estimated partition coefficient for NO2 of 2.7 between n-octanol and water, and 1.5 between lipid membranes and water, meaning that NO2 is a moderately hydrophobic molecule (less than NO, more than CO2). Based on the solubility-diffusion permeability theory, the permeability coefficient was estimated to be 5cms−1, up to 4000 times higher than that of peroxynitrous acid. It is concluded that lipid membranes are not significant barriers to NO2 transport.