Diamagnetic Gas Research Articles

Study on the Aggregation Performance of Nitrogen and Oxygen Gas Based on Permanent Magnet Gradient Magnetic

Oxygen and nitrogen in the air have different magnetic properties in a magnetic field. Oxygen and nitrogen are paramagnetic gases and diamagnetic gases, and the magnetizing force received in a gradient magnetic field is in opposite directions. Based on the magnetization theory and simulation experiment analysis, this paper uses the difference in the direction and magnitude of the magnetization force of oxygen and nitrogen in a gradient magnetic field to study the force state of oxygen and nitrogen molecules in the input air in a gradient magnetic field and the oxygen mass fraction of the output gas to explore effective ways to obtain oxygen-enriched gas. The results of this study can provide oxygen-enriched gas for operations such as oxygen-enriched combustion technology and sewage treatment engineering, and improve operational efficiency.

Exploring the radical nature of a carbon surface by electron paramagnetic resonance and a calibrated gas flow.

While the first Electron Paramagnetic Resonance (EPR) studies regarding the effects of oxidation on the structure and stability of carbon radicals date back to the early 1980s the focus of these early papers primarily characterized the changes to the structures under extremely harsh conditions (pH or temperature)(1-3). It is also known that paramagnetic molecular oxygen undergoes a Heisenberg spin exchange interaction with stable radicals that extremely broadens the EPR signal(4-6). Recently, we reported interesting results where this interaction of molecular oxygen with a certain part of the existing stable radical structure can be reversibly affected simply by flowing a diamagnetic gas through the carbon samples at STP(7). As flows of He, CO2, and N2 had a similar effect these interactions occur at the surface area of the macropore system. This manuscript highlights the experimental techniques, work-up, and analysis towards affecting the existing stable radical nature in the carbon structures. It is hoped that it will help towards further development and understanding of these interactions in the community at large.

Exploring the Radical Nature of a Carbon Surface by Electron Paramagnetic Resonance and a Calibrated Gas Flow

While the first Electron Paramagnetic Resonance (EPR) studies regarding the effects of oxidation on the structure and stability of carbon radicals date back to the early 1980s the focus of these early papers primarily characterized the changes to the structures under extremely harsh conditions (pH or temperature)1-3. It is also known that paramagnetic molecular oxygen undergoes a Heisenberg spin exchange interaction with stable radicals that extremely broadens the EPR signal4-6. Recently, we reported interesting results where this interaction of molecular oxygen with a certain part of the existing stable radical structure can be reversibly affected simply by flowing a diamagnetic gas through the carbon samples at STP7. As flows of He, CO2, and N2 had a similar effect these interactions occur at the surface area of the macropore system. This manuscript highlights the experimental techniques, work-up, and analysis towards affecting the existing stable radical nature in the carbon structures. It is hoped that it will help towards further development and understanding of these interactions in the community at large.

Elucidating the role of stable carbon radicals in the low temperature oxidation of coals by coupled EPR–NMR spectroscopy – a method to characterize surfaces of porous carbon materials

Recently, the nature of the carbon radicals stabilized in various coals was characterized using Electron Paramagnetic Resonance (EPR) spectroscopy. It was demonstrated that introducing diamagnetic gases, such as He, CO2, or N2, under STP conditions to the coal surface induces the appearance of a new type of carbon surface radical. This interesting phenomenon was not observed for all coal types, which suggests that the use of EPR measurements can provide information on functional groups that exist on the carbon surface. In the current study coupling Nuclear Magnetic Resonance (NMR) with gas flow in situ EPR measurements significantly enhances the ability to characterize the nature of these radicals and the surface functional groups of coal samples. It was observed that the oxidative reaction with aliphatic groups leads to the increase in stable carbon centered radicals. In addition, there are some species of carbon centered radicals that show reversible binding to O2. This phenomena, however, is dependent on the coal rank, sample porosity and the degree of the coal sample to undergo structural changes under the LTO process. These findings shed new light onto the complex heterogeneous low temperature oxidation reactions occurring at the coal surface.

Calculation of Critical Points in Gas−Condensate Mixtures under the Influence of Magnetic Fields

The mathematical conditions representing the gas−liquid critical points of multicomponent mixtures are used to compute the gas−liquid critical points of diamagnetic gas−condensate fluids of interest to the oil industry, where the effect of a static magnetic field on calculated critical points is studied for the first time. Magneto-chemical fugacity derivatives, required to fulfill the quadratic and cubic forms of the Helmholtz free energy at the critical points, have been obtained from a recently developed theory of phase equilibria in diamagnetic multicomponent fluids and numerical differentiation (Canas-Marin, W. A.; Ortiz-Arango, J. D.; Guerrero-Aconcha, U. E.; Lira-Galeana, C. AIChE J. 2006, 52 (8), 2887−2897). Results in diamagnetic synthetic gas−condensate mixtures show that a magnetic field can increase or decrease the critical points depending on mixture composition and the extent of the applied magnetic field. For mixtures rich in heavy diamagnetic substances (i.e., hydrocarbon oils), the critical points have an initial tendency to decrease up to a certain value of the field and then to increase with the applied magnetic field. If high amounts of light diamagnetic components are present (i.e., gases), the critical properties always increase with the applied field. The effect of the applied magnetic field on the stability limit of these mixtures is also studied in detail.

Oxygen Separation/Enrichment From Atmospheric Air Using Magnetizing Force

Oxygen is a paramagnetic gas and it has relatively high magnetic susceptibility. On the contrary, nitrogen is a diamagnetic gas and it has relatively low and negative magnetic susceptibility. This results in countermagnetizing forces acting on these gases. The characteristics of oxygen separation/enrichment from atmospheric air in a capsule and air flow in a parallel-plate duct using a magnetizing force were investigated numerically. The direct simulation Monte Carlo (DSMC) method was utilized to obtain distribution of oxygen concentration of air under a strong magnetic field gradient. The molecular movement was calculated by taking into account the magnetizing forces on the molecules. The computations were performed for a wide range of pressure and magnetic flux density gradient. Quantitative characteristics of oxygen separation/enrichment from atmospheric air under a strong magnetic field gradient and a parameter which governs this phenomenon are obtained from the simulation results.

Modeling and simulation of trickle-bed magnetohydrodynamics in inhomogeneous magnetic fields

External inhomogeneous magnetic fields exert a magnetization body force. This force may prove practical in the case of electrically non-conducting and magnetically permeable fluids and may find positive echo in hydrodynamic intensification of chemical processes. Hence, in acting on paramagnetic or diamagnetic gases and liquids, this force can modify the direction as well as the magnitude of the gravitational force. As an intellectual illustration of the potential of this novel route, the ability to influence two-phase flows through packed bed reactors by application of external inhomogeneous magnetic fields was investigated theoretically. The analysis was carried out using an isothermal unidirectional two-fluid magneto-hydrodynamic model based on the volume–average mass and momentum balance equations for the description of two-phase down-flow throughout a vertically oriented and spatially uniform magnetic-field gradient. The magneto-hydrodynamics effects on trickle flow were displayed in terms of liquid hold-up and pressure drop under paramagnetic gas–diamagnetic liquid, paramagnetic gas and liquid, diamagnetic gas and liquid, diamagnetic gas–paramagnetic liquid combinations.

On the evolution of the nova-like variable AE Aquarii

A possible evolution for the enigmatic cataclysmic variable AE Aquarii is considered that may put into context the long orbital period and short white dwarf rotation period compared with other DQ Her systems. It has been shown that mass transfer could have been initiated when the secondary KIV‐V star was already somewhat evolved when it established Roche lobe contact. In this initial phase the orbital period of the system was probably Porb,i ≈ 8.5 h, and the white dwarf rotation period P∗,i > 1 h. Mass transfer in the form of diamagnetic gas blobs will result in an initial discless accretion process, resulting in an efficient drain of the binary orbital angular momentum. Since the initial mass ratio of the binary was probably qi ∼ 0.8, a high mass transfer rate and a slow expansion of the Roche lobe of the secondary star followed, accompanied by a fast expanding secondary following the mass loss. This could have resulted in the KIV‐V secondary flooding its Roche surface, causing a run-away mass transfer of − ˙ M 2 10 20 gs −1 (0.2 ˙

1009 強磁場による常磁性ガス/反磁性ガス流れの分離に関する数値解析

Two-dimensional numerical calculations have been performed on separation of paramagnetic gas flow (such as air flow) and diamagnetic gas flow (such as carbon dioxide gas flow) from mixture of paramagnetic and diamagnetic gas flows by imposing a strong magnetic field with a field gradient. One continuity equation for the total fluid, two momentum equations for the total fluid including the magnetic force term and one mass transfer equation for the diamagnetic gas including the forced diffusion term are solved by the finite difference method . Calculation results show that there is possibility of separation of paramagnetic gas flow and diamagnetic gas flow for strong magnetic fields greater than ∿20 T.

A superconducting filter to separate an oxygen and argon mixture

Hot isostatic pressing in an oxygen atmosphere, known as O2-HIP method, has been used successfully to synthesize oxide materials, as well as to produce porous materials. In this paper a porous superconducting oxide is synthesized by this method and its application as a gas filter is described. Porous superconductors can be used to separate a mixture of paramagnetic and diamagnetic gases, such as oxygen and argon. Separation occurs after a magnetic field is applied and is based on the Meissner effect. Experimental results showed that the oxygen content of an oxygen/argon mixture increased after passing through a filter with large pore size (about 10 μm).

Spin rates and mass loss in accreting T Tauri stars

The accretion flows in T Tauri stars may consist largely of diamagnetic gas blobs which interact with magnetic loops on the central star through a surface drag. We show that this mechanism can eject blobs from the system in directions away from the disc plane; the angular momentum balance with the accreted blobs gives stellar rotation rates similar to those observed. About one-third of the disc material escapes from the system; given a suitable surrounding gas cavity, this can produce outflows with similar properties to the optical jets observed in T Tauri stars.

‘‘Walls’’ of a paramagnetic gas in a magnetic field gradient

A quantitative explanation is given for the recently reported ‘‘walls’’ formed by a paramagnetic gas in a magnetic field gradient, that can guide the flow of a diamagnetic gas down a negative field gradient, or reflect the flow from a positive field gradient.

Magnetic properties of a diamagnetic gas in a resonance radiation field

An investigation is made of the change in the magnetic properties of a diamagnetic molecule (atom) induced by a resonance optical radiation field. Calculations are made for the 0→1 molecular transition in the presence of an external magnetostatic field. Expressions are derived for the magnetization and the magnetic susceptibility of the molecule, which depend nonlinearly on the light wave intensity, in the case of longitudinal and transverse directions of the external magnetic field with respect to the direction of propagation of the radiation. It is shown that the field-induced nonlinear magnetic susceptibility of a diamagnetic substance can change sign and increase considerably (by several orders of magnitude compared with the linear diamagnetic susceptibility). The field-induced nonlinear magnetization of the substance does not depend on its magnetic properties and is the same for diamagnetic and paramagnetic substances.

Heat conduction in a nearly collisionless molecular gas

Transport phenomena in molecular gases and the respective field effects have so far been analyzed in the hydrodynamic and Knudsen regimes. In between there is a rather large gap covered by the transition regime. For the case of heat conduction through a diatomic diamagnetic gas between parallel plates an attempt is made to partially bridge the gap by the beginning of a density expansion derived through iteration of an integral form of the Boltzmann equation. Second-order perturbation in non-sphericity of both intermolecular and gas-wall interactions is applied to determine the effect of a magnetic field. Explicit expressions are derived for a simple model.

The effect of a magnetic field on the thermal conductivity of NO–N2 and NO–H2 mixtures

The fractional change of the longitudinal coefficient of heat conductivity, (Δλ⊥/λ), due to a magnetic field applied normal to the temperature gradient in a hot-wire thermal conductivity cell, has been studied for the NO–N2 and NO–H2 mixtures at different concentrations. The contribution, to (Δλ⊥/λ), of the Senftleben–Beenakker effect in the diamagnetic gas (N2 or H2) has been observed at the higher values of applied H/p, where H is the strength of the magnetic field, and P, pressure. Neglecting this feature, we have interpreted the results by applying an extension of Köhler and Raum’s theory. The relevant effective cross sections have also been evaluated from the experimental data.

Determination of Magnetic Susceptibilities of Paramagnetic Gases by an Improved Viscometer Method

Abstract An improved viscometer method has been applied to the determination of the magnetic susceptibility of a paramagnetic gas and found to be of use in the analysis of a paramagnetic gas mixed in a diamagnetic gas. The magnetic susceptibilities of oxygen and nitrogen monoxide have been determined to within ±0.5% using a saturated aqueous solution of sodium chloride as the working liquid.

Magnetic field induced temperature changes in cryogenic liquids: N 2, Ar, and He 4

Measurements of magnetic field-induced changes in hydrostatic head corrections are reported for columns of liquid N 2 and Ar at their normal boiling points and for liquid He 4 between 2.15 and 4.2 K, in static magnetic fields to 15 T. The results for very high purity N 2 and Ar are in good agreement with calculations based on gas susceptibilities; diamagnetic coolings of − 32 ± 1.5 and − 64 ± 6 mK are observed for liquid N 2 and Ar respectively, at 15 T. However, O 2 contamination in amounts as small as 0.1 at % can drastically after the observed temperature changes. The measurements on He 4 above 3 K are also in good agreement with calculations based on the diamagnetic gas susceptibility. Below 3 K, the results deviate from the calculation in a paramagnetic direction; just above the λ-point, paramagnetic warnings of ∼ 10 mK are observed for a field of 15 T.

Magnetic-field Induced Change of the Viscosity of Diamagnetic Gases with Anisotropic Magnetic Susceptibility

Abstract The influence of a high magnetic field on the viscosity of diamagnetic gases of linear, symmetric and asymmetric top molecules is studied within the frame-work of the kinetic theory based on the Waldmann-Snider equation. The quadratic Zeeman effect associated with the anisotropic magnetic susceptibility is taken into account in addition to the usual linear Zeeman splitting.

MAGNETOTHERMAL CONVECTION OF POLYATOMIC GASES IN HOMOGENEOUS MAGNETIC FIELDS Part I: Theory

Abstract The theory of magnetothermal convection of gases in homogeneous magnetic fields is developed from magnetogas-dynamic theory. Application is made to nonionized paramagnetic and diamagnetic gases between parallel vertical plates. An additive contribution to the natural thermal convection heat transfer results from the temperature dependence of the magnetic permeability of the gas. The result may be expressed parametrically in a dimensionless magnctoconvection number, which characterizes the magnetothermal contribution to the total heat transfer just as the Grashof number characterizes the natural thermal contribution. For oxygen gas at low pressure the magnetothermal contribution is shown to be proportional to p 3 H 2(ΔT)2 /ηT 5 where p is the gas pressure, H is the magnetic field strength, ΔT is the temperature difference between plates, η is the viscosity coefficient and T is the absolute temperature.

Effect of Magnetic Field on Reduction of Haematite

SKORSKI1 reported that a magnetic field increased the reduction rate of haematite, Fe203, in hydrogen at about 300° C. He tried to explain this effect as due to a greater pressure of “paramagnetic” ortho-hydrogen near magnetized iron particles. A reduced reduction rate in a magnetic field was observed with diamagnetic gases like CO and CH4. Because no calculations on the proposed magnetic effect were given, some comments are called for.