Flux Gradient Research Articles

Guide for Nonequilibrium Molecular Dynamics Simulations of Organic Solvent Transport in Nanopores: The Case of 2D MXene Membranes.

Organic solvent nanofiltration (OSN) stands out as an energy-efficient and low-carbon footprint technology, currently reliant on polymeric membranes. With their exceptional chemical stability and tunable sieving properties, two-dimensional (2D) nanolaminate membranes present distinct advantages over conventional polymer-based membranes, attracting tremendous interest in the OSN community. Computational approaches for designing innovative 2D nanolaminates exhibit significant potential for the future of OSN technology. Imitating the pressure gradient in filtration processes by applying an external force to atoms within a predefined slab, boundary-driven nonequilibrium molecular dynamics ((BD)-NEMD) is a state-of-the-art simulation method with a proven track record in investigating the water transport in nanopores. Nevertheless, implementation of (BD)-NEMD for a broad range of solvents poses a challenge in estimating the OSN performance of theoretical membranes. In this work, we developed a (BD)-NEMD protocol that elucidates the effects of several computational details often overlooked in water simulations but are crucial for bulky solvent systems. We employed a MXene (Ti3C2O2) nanochannel as a model membrane and examined the transport of nine solvents (methanol, ethanol, acetone, n-hexane, n-heptane, toluene, ethyl acetate, dichloromethane, and water) having different properties. First, the impact of ensemble type, thermostatting, channel wall model, and restraining force constant was elaborated. After optimizing the thermostatting approach, we demonstrated that the location of the force slab particularly affects the flux of bulky solvents by changing the density distribution in the feed and permeate sides. Similarly, the uniformity of intramolecular force distribution in bulky solvents and resulting flux are shown to be prone to manipulation by slab boundaries. Next, the magnitudes of the external force generating a linear relation between the pressure gradient and solvent flux were identified for each solvent to ensure that calculated fluxes could be extrapolated to experimentally related pressures. This linear relation was also validated for a mixture system containing 50% ethanol and 50% water. We then correlated the calculated solvent permeances with various solvent properties, such as viscosity, Hansen solubility parameters, kinetic diameter, and interaction energy. Remarkably, we observed a linear correlation with an R2 value of 0.96 between permeance and the combined parameter of viscosity and interaction energy. Finally, the solvent permeances calculated with our proposed methodology closely align with the experimentally reported data. Overall, our work aims to serve as a practical guide and bridge the gap in established simulation methods that are suited for a broad range of solvents and membrane materials.

Thermal Conductivity Measurement System for Functional and Structural Products

An automated system for measuring the thermal conductivity of functional and structural materials was developed. The main building blocks of the setup are the following: heating unit and cooling unit creating a heat flux gradient in the test sample; thermal resistances for temperature registration and control; and thermal pads for better contact between parts of the setup and the sample. The effect of the thermal conductivity of thermal pads and thermal resistances on the distribution of thermal fields in the developed setup was studied by computer modelling. A control software for the measuring setup was developed based on the hardware implementation of the steady-state Fourier’s law-based method for the determination of thermal conductivity. The stopping criterion for the setup control software is the equality of heat fluxes in the heating and cooling units, as well as the stability of the thermal conductivity coefficient readings. The testing and calibration of the device were carried out using a sample of pure aluminum (99.999 wt.% Al). It was found that the experimental value of the thermal conductivity coefficient of the aluminum sample at room temperature (T = 22 °C) is <λ> = 243 ± 3 W/m·K. This value of the thermal conductivity coefficient is consistent with the literature data and experimental values obtained by the laser flash method, which ranges within λ = 210–260 W/m·K.

Multi-year gradient measurements of sea spray fluxes over the Baltic Sea and the North Atlantic Ocean

Abstract. Ship-based measurements of sea spray aerosol (SSA) gradient fluxes in the size range of 0.5–47 µm in diameter were conducted between 2009–2017 in both the Baltic Sea and the North Atlantic Ocean. Measured total SSA fluxes varied between 8.9 × 103 ± 6.8 × 105 m−2 s−1 for the Baltic Sea and 1.0 × 104 ± 105 m−2 s−1 for the Atlantic Ocean. The analysis uncovered a significant decrease (by a factor of 2.2 in the wind speed range of 10.5–14.5 m s−1) in SSA fluxes, with chlorophyll a (chl a) concentration higher than 3.5 mg m−3 in the Baltic Sea area. We found statistically significant correlations for both regions of interest between SSA fluxes and various environmental factors, including wind speed, wind acceleration, wave age, significant wave height, and wave Reynolds number. Our findings indicate that higher chl a concentrations are associated with reduced SSA fluxes at higher wind speeds in the Baltic Sea, while the influence of wave age showed higher aerosol emissions in the Baltic Sea for younger waves compared to the Atlantic Ocean. These insights underscore the complex interplay between biological activity and physical dynamics in regulating SSA emissions. Additionally, in both measurement regions, we observed weak correlations between SSA fluxes and air and water temperature and between SSA fluxes and atmospheric stability. Comparing the Baltic Sea and the North Atlantic, we noted distinct emission behaviors, with higher emissions in the Baltic Sea at low wave age values compared to the Atlantic Ocean. This study represents the first comparative analysis of SSA flux measurements using the same methodology in these contrasting marine environments.

A High-Order Well-Balanced Discontinuous Galerkin Method for Hyperbolic Balance Laws Based on the Gauss-Lobatto Quadrature Rules

In this paper, we develop a high-order well-balanced discontinuous Galerkin method for hyperbolic balance laws based on the Gauss-Lobatto quadrature rules. Important applications of the method include preserving the non-hydrostatic equilibria of shallow water equations with non-flat bottom topography and Euler equations in gravitational fields. The well-balanced property is achieved through two essential components. First, the source term is reformulated in a flux-gradient form in the local reference equilibrium state to mimic the true flux gradient in the balance laws. Consequently, the source term integral is discretized using the same approach as the flux integral at Gauss-Lobatto quadrature points, ensuring that the source term is exactly balanced by the flux in equilibrium states. Our method differs from existing well-balanced DG methods for shallow water equations with non-hydrostatic equilibria, particularly in the aspect that it does not require the decomposition of the source term integral. The effectiveness of our method is demonstrated through ample numerical tests.

Capturing non-equilibrium in hypersonic flows: Insights from a two-temperature model in polyatomic rarefied gases

The study utilizes a two-temperature model to analyze non-equilibrium in normal shocks within hypersonic flows in polyatomic rarefied gases. Derived from the extended second law of thermodynamics, this model separates translational and internal temperatures in polyatomic gases, providing a more accurate depiction of non-equilibrium gas flow compared to classical theories like the Navier–Stokes and Fourier (NSF) system. Notably, the analysis reveals that the two-temperature model incorporates an additional contribution to the heat flux due to the gradient of the dynamic temperature, resulting in improved accuracy, especially for high Mach numbers. Results show that the model gives satisfactory shock density and temperature profiles up to Mach 10, with very good agreement observed up to Mach 6.1 compared to the classical NSF model. We conduct an order of magnitude analysis on the dynamic temperature and heat flux gradients appearing in the new constitutive equation using the Mott-Smith method. This analysis highlights the impact of these terms on accurately modeling polyatomic gas behavior in high-speed flows. The effects of bulk viscosity and incoming temperature on shock profiles are also investigated, contributing to a better understanding of shock wave structures in polyatomic gases and their implications for hypersonic flow dynamics.

Modified Cattaneo-Vernotte equation for heat transfer in solids

We propose a modified relation between heat flux and temperature gradient, which leads to a second-order equation describing the evolution of temperature in solids with finite rate of propagation. A comparison of the temperature field spreading in the framework of Fourier, Cattaneo-Vernotte (CV) and modified Cattaneo-Vernotte (MCV) equations is discussed. The comparative analysis of MCV and Fourier solutions is carried out on the example of simple one-dimensional problem of a plate cooling.

Evaluation of impacts of biosolids application and drainage water management on soil N2O and CH4 emissions using the flux gradient method

Existing studies have shown contradictory findings with respect to whether biosolids applications on agricultural lands lead to intensification of soil greenhouse gas (GHG) emissions. Here, we describe the results of deployment of the micrometeorological flux gradient method to quantify post-biosolid soil emissions of nitrous oxide (N2O) and methane (CH4) on a farm with drainage water management (DWM) on the Eastern Shore of Maryland. The fluxes following biosolid additions to cornfields in 2020 were compared with fluxes from the same farm in 2018, when no fertilizer was applied to soybeans, and in 2019, when urea ammonium nitrate (UAN) was applied to corn. Extractable soil nitrate was highest following biosolids application, contributing to the highest N2O emissions in the growing season of 2020 compared to 2018 (no fertilizer) and 2019 (UAN). Other contributing factors include the low C:N ratio of the biosolids and the above average precipitation in 2020. In contrast, different fertilization regimes did not generate distinct differences for CH4 fluxes, which were very low in all three years. No statistically significant treatment effect of DWM was found for either N2O or CH4 during the peak emission period after biosolids application, which aligns with the result of our earlier research. Annualized estimated N2O emission factors (EFs) for biosolids addition were 5–6 % in the DWM and 3–4 % in the non-DWM fields, although this includes uncertainties associated with gap filling. These biosolids EFs are 2–3 times the N2O EF for synthetic fertilizer application at this same farm in 2019 (1–2.5 %) and 2–4 times the IPCC Tier 1 EF (1.6 %) for synthetic fertilizer, demonstrating the intensification effect of biosolids addition on soil N2O emissions for the cropland studied here.

Estimation of Urban Greenhouse Gas Fluxes from Mole Fraction Measurements Using Monin–Obukhov Similarity Theory

Abstract The purpose of this study is to determine whether urban greenhouse gas (GHG) fluxes can be quantified from tower-based mole fraction measurements using Monin–Obukhov similarity theory (MOST). Tower-based GHG mole fraction networks are used in many cities to quantify whole-city GHG emissions. Local-scale, micrometeorological flux estimates would complement whole-city estimates from atmospheric inversions. CO2 mole fraction and eddy-covariance flux data at an urban site in Indianapolis, Indiana, from October 2020 through January 2022 are analyzed. Using MOST flux–variance and flux–gradient relationships, CO2 fluxes were calculated using these mole fraction data and compared to the eddy-covariance fluxes. MOST-based fluxes were calculated using varying measurement heights and methods of estimating stability. The MOST flux–variance relationship method showed good temporal correlation with eddy-covariance fluxes at this site but overestimated flux magnitudes. Fluxes calculated using flux–gradient relationships showed lower temporal correlation with eddy-covariance fluxes but closer magnitudes to eddy-covariance fluxes. Measurement heights closer to ground level produce more precise flux estimates for both MOST-based methods. For flux–gradient methods, flux estimates are more accurate and precise when low-altitude measurements are combined with a large vertical separation between measurement heights. When stability estimates based on eddy-covariance flux measurements are replaced with stability estimates based on the weather station or net radiation data, the MOST-based fluxes still capture the temporal patterns measured via eddy covariance. Based on these results, MOST can be used to estimate the temporal patterns in local GHG fluxes at mole fraction tower sites, complementing the small number of eddy-covariance flux measurements available in urban settings.

Power enhancement of vibration energy harvesters by way of magnetic flux gradient analysis of electromagnetic induction

This study proposes strategies to enhance the conversion of mechanical energy to electrical energy in cylindrical electromagnetic induction-type vibration energy harvesters (VEH) using disc or ring-shaped magnets and ring-shaped coils. The rationale behind these strategies has been substantiated by an analysis of magnetic flux gradients based on simulations. In particular, the utilization of a repulsive magnet pair and a yoke has been proposed to maximize the magnetic flux gradient at the coil winding position by manipulating the magnetic flux path. Simulation results confirm that the use of a yoke can produce a nearly 5.8-fold increase in power consumption at the external load. Additionally, the study demonstrates that the positioning and thickness settings of the coil are critical for improving the electrical output based on the spatial distribution of the magnetic flux gradient. Within the same magnet topology, points where power generation is not feasible due to a zero magnetic flux gradient are identified, besides a nearly 5.3-fold increase in observed power generation depending on coil placement. Given the structural feasibility of VEH implementation, a design for a moving magnet VEH utilizing ring magnets with a yoke enclosure is proposed, demonstrating that it can generate power at nearly 85% of the level attributed to using disc magnets.

Assessment of carbon flux gradients and dominant processes in a subtropical highly urbanized coastal ecosystem

Highly urbanized coastal ecosystems are vital in the global carbon budget. However, there are limited researches on carbon flux gradients in these nearshore areas, considering both natural and anthropogenic influences. Through on-site measurements and field samplings during wet-to-dry season in 2023, this study investigated spatial variations and factors affecting carbon fluxes, focusing on the impacts of salinity and eutrophic status in five geographically connected coastal waters of the Guangdong-Hong Kong-Macau Greater Bay Area (GBA). By estimating carbon exchange at land-sea-air interface, dominant processes in carbon dynamics were identified as well. Results showed that partial pressure of CO2 (pCO2) varied from 391 to 2290 μatm, and sea-air CO2 exchange fluxes (FCO2) ranged from -3.07 to 70.07 mmol m–2 d–1, indicating significant geographical distinctions among five coastal waters of the GBA. The total carbon transport from rivers to these nearshore waters was approximated at 6.44 Tg C yr-1, with the Pearl River (PR) contributing 99.7%, primarily in dissolved forms. Atmospheric CO2 release was calculated at 0.29 Tg C yr-1 for studied five coastal waters, primarily as carbon sources, except for Dapeng Bay (DPB) as a sink. CO2 emissions inversely correlated with salinity, yet positively with eutrophication status, particularly in river-dominated estuaries. Moreover, CO2 flux decreased 23 times as eco-status shift from eutrophic to non-eutrophic. River plumes, terrestrial pollutant inputs, and economic structure were underlying drivers, influencing carbon species concentrations and fluxes. Elevated CO2 concentrations in eutrophic coastal waters were mainly attributed to terrestrial carbon and nutrients inputs, supporting active biological respiration and microbial decomposition. Conversely, carbon dynamics potentially depend on the balance of respiration and photosynthesis in non-eutrophic coastal waters. This study offers high geographic precision and specificity of carbon species, and provides land-sea integration insight to understand carbon dynamic mechanisms, promoting advancements in water quality management and climate mitigation.

Thermal magnetization transport analysis featuring darcian and multi-physical rheological characteristics in chemically reactive dual convective tangent-hyperbolic nanomaterial confined by vertical cone

The Soret-Dufour characteristics elaborate the phenomena of cross-diffusion where solutal gradients yield heat flux (Dufour aspect) and thermal gradients engender mass flux (Soret effect). Such consideration finds significance in multi-component fluid systems, influencing both heat-mass transportation processes. This study evaluates the porous medium characteristics in convectively heated tangent-hyperbolic nanomaterial driven by a magnetized convected cone. The analysis features Buongiorno nanomaterial model which accounts Brownian motion together with thermophoresis. Thermal transport expression which reports heat transfer characteristics is modeled by considering thermal radiation, convective thermal conditions and heat generation while mass transfer considers the chemical reaction effects. Dimensional expressions are converted into dimensionless forms deploying similarity transformations ensuing in a set of ODEs (ordinary differential expressions) which are computed by deploying bvp4c algorithm. Graphical and tabular behavior of velocity, nanoparticles concentration and temperature fields is inspected corresponding to related variables. This research highlights key findings, revealing a decrease in Nusselt number with increasing heat generation, Dufour parameter and thermophoresis parameter values while opposite trends are verified for radiation parameter values. The velocity function declines for escalating Weissenberg number, magnetic field and permeability parameters but it upsurges with material and buoyancy parameters.

Enhancing the magnetic field gradient between two superconductors with rotational motion under a background DC field

The ability of bulk high-temperature superconductors to trap magnetic flux densities up to one order of magnitude larger than the saturation magnetization of conventional ferromagnetic materials offers the prospect of generating large magnetic flux density gradients. Combining multiple superconductors, akin to assembling a Halbach array of permanent magnets, may increase the generated gradient even further. The associated challenge is that superconductors are prone to demagnetization when exposed to field components perpendicular to their main magnetization direction. In the present work, we investigate the magnetic flux density gradient achieved with a pair of cubic, bulk, large-grain melt-textured superconductors in the presence of a background DC magnetic field at 77 K. We investigate the increase of the performance when decreasing the temperature down to 59 K. The studied configuration consists in two facing cubic YBa2Cu3O 7−x superconductors of 6 mm side with anti-parallel magnetization directions. It is obtained after the simultaneous magnetization of the samples followed by a rotation of 180∘ of the top superconductor. Although the background field reduces the trapped field ability of individual samples, it is shown that this phenomenon is significantly mitigated at 65 K and at 59 K compared to 77 K. The results reveal that a sample-to-sample distance ( ∼16 mm) of the order of their size is sufficient to avoid any mutual demagnetization effect during the rotational motion. Furthermore, it is shown that decreasing the temperature is not only beneficial in increasing the field and field gradient achieved but also in extending the range of background fields in which the superconductor can be rotated without demagnetization. This superconducting assembly yields a magnetic flux density gradient exceeding that of an isolated superconductor and has the potential to surpass the capabilities of permanent magnets.

Flow Distribution in Molten Salt Receiver Panels at High Flux Gradients

This paper presents a simulation study on critical mass flow distributions in receiver panels of commercial-scale molten salt towers (MST). Despite sophisticated aimpoint optimizations, the flux density distribution on an MST receiver in actual operation contains significant vertical and horizontal gradients. This study investigated how the latter affects the mass flow distribution among the parallel absorber tubes in each panel. A parametric study applied a discretized dynamic thermohydraulic model of a commercial scale receiver design, highlighting at which mass flow rates, flux density gradients and mean flux densities the flow distribution can become critical. Excessive temperature developments were observed, suggesting maintaining appropriate minimal mass flow rates to avoid damaging tube walls and the molten salt chemistry.

Understanding underlying physical mechanism reveals early warning indicators and key elements for adaptive infections disease networks.

The study of infectious diseases holds significant scientific and societal importance, yet current research on the mechanisms of disease emergence and prediction methods still face challenging issues. This research uses the landscape and flux theoretical framework to reveal the non-equilibrium dynamics of adaptive infectious diseases and uncover its underlying physical mechanism. This allows the quantification of dynamics, characterizing the system with two basins of attraction determined by gradient and rotational flux forces. Quantification of entropy production rates provides insights into the system deviating from equilibrium and associated dissipative costs. The study identifies early warning indicators for the critical transition, emphasizing the advantage of observing time irreversibility from time series over theoretical entropy production and flux. The presence of rotational flux leads to an irreversible pathway between disease states. Through global sensitivity analysis, we identified the key factors influencing infectious diseases. In summary, this research offers valuable insights into infectious disease dynamics and presents a practical approach for predicting the onset of critical transition, addressing existing research gaps.

Gold content determination in small core-samples by instrumental neutron activation analysis

Application of instrumental neutron activation analysis (INAA) based on the relative method of concentration standardization was considered to determine Au content in small solid core-samples of the gold-bearing ores and rocks up to 10 g of the mass. The small core-samples about 10 mm in diameter and 22-23 mm in length were cut from the previously collected ore lumps or in-situ using a handheld drilling rig. The studied small core-samples and the polyethylene capsules of the same dimensions filled up with the corresponding certified reference material (CRM) were irradiated for 2 min by a lower density neutron flux with the help of the automated pneumatic transport system (PTS). Maximum mass and dimensions of the core-samples corresponded to the PTS design and to the conditions of its safe operation. A special device was made to fix the transport capsules in the stable counting geometry making possible to eliminate the influence of the neutron flux gradient during irradiation. Due to the substantial differences in CRM and solid sample densities, corrections for neutron self-shielding and for gamma-ray self-absorption by the core-samples were applied. The method was tried to analyze Au content in 170 small core-samples presenting different gold-bearing ores and country rocks from the Kazakhstan’s gold-barite-polymetallic deposit Maikain. This approach, rather simple methodically and requiring no unique equipment, can be used to assess gold resources together with the methods of geostatistics.

Increasing complexity in Aerodynamic Gradient flux calculations inside the roughness sublayer applied on a two-year dataset

Over tall canopies such as forests the atmospheric surface layer is subdivided into an inertial sublayer (ISL) and a roughness sublayer (RSL). Inside the RSL the classic aerodynamic gradient method using Monin-Obukhov similarity theory (MOST) by itself does not represent the gradient well and is insufficient to calculate fluxes. Over the past decades multiple studies have proposed methods to extend MOST to account for the different turbulent conditions within the RSL, containing a wide range of approaches and complexity. In this study we investigate how much complexity is necessary to calculate the flux more accurately and what we can learn from the respective complexity. A large dataset is required to assess the statistical robustness of the respective complexity during different environmental conditions. To this end, we study and apply the effect of forest roughness and directional heterogeneity in our flux calculations on a two-year dataset (2009-2010) of the sensible heat flux measured over a Douglas fir forest in the Netherlands. We apply standard MOST, an observational based method (the α-factor) and a physically based method (Harman and Finnigan, 2007, 2008) (hereafter HF07/08) together with a range of methods for the displacement height (d). Our results show that both a simple method (the α-factor) and a complex method (HF07/08) are able to more accurately represent the flux but that, as expected, standard MOST (regardless of the method estimating d) alone is insufficient. Both the α-factor and (HF07/08) allow to analyze large scale patterns in canopy turbulence. Differences between the methods lie in the level of detail and practical usability.

Effect of trapezoidal plasma density region in bubble wakefield acceleration

In the process of bubble wakefield acceleration highly nonlinear region is developed inside plasma, which intuitively suggests that nonuniform plasma density having gradients may be more suited to achieve large nonlinearity in the system. Moreover, when an intense laser pulse propagates in a plasma, it is subjected to various instabilities and these instabilities can be controlled by plasma density profiles which effectively control the energy and flux of the accelerated particles. Considering all these points we investigate in the present work the scaling effect of up-ramp and down-ramp regions in plasma density profile on the bubble wakefield. These regions are separated by a plateau region (maximum density) enabling the density to have trapezoidal profile. With this density profile, the bubble wakefield acceleration is examined considering four different lengths of up-ramp and plateau regions keeping a constant down-ramp length. Increasing steepness of up-ramp length (larger density gradient), i.e., lowering the length of up-ramp and increasing the plateau length creates a bubble having higher wakefield strength, resulting into higher accumulation of plasma electrons at its tail and higher energy spectrum with higher kinetic energy gradient and Poynting flux of accelerated electrons.

Cell migration dynamics explained by the coupling of mechanics with electrochemistry and pH regulation

Anisotropic environmental signals or polarized membrane ion/solute carriers can generate spatially varying intracellular gradients, leading to polarized cell dynamics. For example, the directional migration of neutrophils, galvanotaxis of glioblastoma, and water flux in kidney cells all result from the polarized distribution of membrane ion carriers and other intracellular components. The underlying physical mechanisms behind how polarized ion carriers interact with environmental signals are not well studied. Here, we use a physiology-relevant, physics-based mathematical model to reveal how ion carriers generate intracellular ion and voltage gradients. The model can discern the contribution of individual ion carriers to the intracellular pH gradient, electric potential, and water flux. We discover that an extracellular pH gradient leads to an intracellular pH gradient via chloride-bicarbonate exchangers, whereas an extracellular electric field leads to an intracellular electric potential gradient via passive potassium channels. In addition, mechanical-biochemical coupling can modulate actin distribution and flow, creating a biphasic dependence of cell speed on water flux. Moreover, we find that F-actin interaction with NHE alone can generate cell movement, even when other ion carriers are not polarized. Taken together, the model highlights the importance of cell ion dynamics in modulating cell migration and cytoskeletal dynamics. Published by the American Physical Society 2024

Mixed convection by buoyancy and magnetothermal forces

The magnetic force in the paramagnetic fluid depends on the local gradient of magnetic flux density and the temperature-dependent magnetic susceptibility. In the presence of the gravity, the buoyant force due to the temperature difference additionally overlaps, and the resultant flow becomes a mixed convection. In this study, the effect of the temperature-dependent magnetic force (magnetothermal force) on the natural convection was numerically investigated. The magnetic field formed by the permanent-magnet array was employed and effective one was discussed in terms of the heat transfer. A three-dimensional Rayleigh-Benard convection simulation was conducted with the magnet array below the bottom hot wall. It was found that the magnetothermal force enhances the convection not only where the magnet locates but also away from the magnet due to the force profile.

MALTA: A Zonally Averaged Global Atmospheric Transport Model for Long‐Lived Trace Gases

AbstractWe present a two‐dimensional, zonally averaged global model of atmospheric transport named MALTA: Model of Averaged in Longitude Transport in the Atmosphere. It aims to be accessible to a broad community of users, with the primary function of quantifying emissions of greenhouse gases and ozone depleting substances. The model transport is derived from meteorological reanalysis data and flux‐gradient experiments using a three‐dimensional transport model. Atmospheric sinks are prescribed loss frequency fields. The zonally averaged model simulates important large‐scale transport features such as the influence on trace gas concentrations of the quasi‐biennial oscillation and variations in inter‐hemispheric transport rates. Stratosphere‐troposphere exchange is comparable to a three‐dimensional model and inter‐hemispheric transport is faster by up to 0.3 years than typical transport times of three‐dimensional models, depending on the metric used. Validation of the model shows that it can estimate emissions of CFC‐11 from an incorrect a priori emissions field well using three‐dimensional (3D) mole fraction fields generated using a different 3D model than which the flux gradient relationships were derived. The model is open source and is expected to be applicable to a wide range of studies requiring a fast, simple model of atmospheric transport and chemical processes for estimating associated emissions or mole fractions.