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Avian Pasteurella multocida infection, can cause serious economic losses to the poultry industry every year. The inactivated vaccines of avian Pasteurella multocida are used to prevent infection. Increasing the cell density of avian Pasteurella multocida is the key to the application of these inactivated vaccines. This can be achieved by controlling the feeding strategy. This study aimed to achieve high-cell-density cultivation of avian Pasteurella multocida by applying an appropriate medium and a rational feeding strategy based on viable cell growth and dissolved oxygen level variation during a fermentation process. An optimized medium suited for the growth of avian P. multocida was used. Meanwhile, besides the online real-time determination of viable cell density, the concentration of glucose was maintained at 1.5 g/L using a glucose-stat feeding strategy after 2 h. The selected nutrient mixture, including yeast extract, tryptone, betaine, VB1, and VH, was fed using a dissolved oxygen feedback feeding strategy after 4 h. As a result, the viable cell density and cell count of avian P. multocida under optimized conditions were increased to OD600: 9.38 and 4.58×1010 CFU/mL, which were higher by 7.27 and 7.26 times than those under the original conditions, respectively.

In current dual porosity/permeability models, there exists a fundamental assumption that the adsorption-induced swelling is distributed uniformly within the representative elementary volume (REV), irrespective of its internal structures and transient processes. However, both internal structures and transient processes can lead to the non-uniform swelling. In this study, we hypothesize that the non-uniform swelling is responsible for why coal permeability in experimental measurements is not only controlled by the effective stress but also is affected by the adsorption-induced swelling. We propose a concept of the swelling triangle composed of swelling paths to characterize the evolution of the non-uniform swelling and serve as a core link in coupled multiphysics. A swelling path is determined by a dimensionless volumetric ratio and a dimensionless swelling ratio. Different swelling paths have the same start and end point, and each swelling path represents a unique swelling case. The swelling path as the diagonal of the triangle represents the case of the uniform swelling while that as the two perpendicular boundaries represents the case of the localized swelling. The paths of all intermediate cases populate inside the triangle. The corresponding relations between the swelling path and the response of coal multiphysics are established by a non-uniform swelling coefficient. We define this method as the triangle approach and corresponding models as swelling path-based ones. The proposed concept and models are verified against a long-term experimental measurement of permeability and strains under constant effective stress. Our results demonstrate that during gas injection, coal multiphysics responses have a close dependence on the swelling path, and that in both future experiments and field predictions, this dependence must be considered.

Long-term permeability experiments have indicated that sorption-induced swelling can switch from internal to bulk depending on the evolutive sorption status. However, this sorption swelling switch mechanism has not been considered in current analytical permeability models. This study introduces a normalized sorption non-equilibrium index (SNEI) to characterize the sorption status, quantify the dynamical variations of matrix swelling accumulation and internal swelling partition, and formulate the sorption swelling switch model. The incorporation of this index into the extended total effective stress concept leads to an analytical transient coal permeability model. Model results show that the sorption swelling switch itself results in the permeability switch under stress-constrained conditions, while the confined bulk swelling suppresses the permeability recovery to the continuous reduction under displacement-constrained conditions. Model verifications show that current experimental observations correspond to the early stages of the transient process, and they could be extended to the whole process with these models. This study demonstrates the importance of the sorption swelling switch in determining permeability evolution using simple boundary conditions. It provides new insights into experimentally revealing the sorption swelling switch in the future, and underscores the requirement of a rigorous model for complex coupled processes in large-scale coal seams.

Abstract Exercise-induced mechanical loading can increase bone strength whilst mechanical unloading enhances bone-loss. Here, we investigated the role of lncRNA NONMMUT004552.2 in unloading-induced bone-loss. Knockout of lncRNA NONMMUT004552.2 in hindlimb-unloaded mice caused an increase in the bone formation and osteoblast activity. The silencing of lncRNA NONMMUT004552.2 also decreased the osteoblast apoptosis and expression of Bax and cleaved caspase-3, increased Bcl-2 protein expression in MC3T3-E1 cells. Mechanistic investigations demonstrated that NONMMUT004552.2 functions as a competing endogenous RNA (ceRNA) to facilitate the protein expression of spectrin repeat containing, nuclear envelope 1 (Syne1) by competitively binding miR-15b-5p and subsequently inhibits the osteoblast differentiation and bone formation in the microgravity unloading environment. These data highlight the importance of the lncRNA NONMMUT004552.2/miR-15b-5p/Syne1 axis for the treatment of osteoporosis.

K subgroup of Avian leukemia virus (ALV-K), as the latest reported exogenous ALV subgroup, can cause severe immunosuppression and tumorigenesis in infected chickens and bring serious threats to the poultry. Culling the positive chickens from breeder flocks is the most effective measurement for controling its infection at present. To setup a specific and rapid method for detecting ALV-K, an immunochromatographic strip (ICS) based on colloidal gold nanoparticles and double monoclonal antibodies (MAbs) immunochemical reaction was successfully developed. The solution containing colloidal gold particles (colloidal 20 nm) was prepared by sodium citrate reduction, and the ascites MAbs against ALV-K were purified and identified. The antibody concentration of the colloidal gold-MAb complex reaction system was 9.6 μg/mL, and the optimum pH was 7.5. The optimum coating concentrations of the captured antibody and quality control antibody on the NC membrane were 1.2 mg/mL and 0.6 mg/mL, respectively. The results showed that the prepared ICS could specifically detect ALV-K and had no cross reaction with exogenous ALV-A/B/J strains. Its sensitivity was 64 TCID50/mL against ALV-K and 0.25 μg/mL against ALV-K gp85 protein. The ICS stored at 4 °C for 180 d, at 25 °C for 45 d, and at 37 °C for 15 d could stably detect ALV-K in the samples. In comparision detection of 128 clinical samples, the coincidence rates in cloacal swab samples, serum samples, egg albumen samples and tissue homogenate samples between the ICS and the commercial ALV p27 antigen ELISA kit were 100 %, 100 %, 96.7 % and 96.9 %, respectively; moreover, the prepared ICS in operations was simpler and more convenient. This study supplies a new specific and rapid method for detecting ALV-K in clinics. This is the first report on the application of nano-colloidal gold ICS in ALV-K differential detection.

Abstract A representative class of kagome materials, AV3Sb5 (A = K, Rb, Cs), hosts several unconventional phases such as superconductivity, $${{\mathbb{Z}}}_{2}$$ Z 2 non-trivial topological states, and electronic nematic states. These can often coexist with intertwined charge-density wave states. Recently, the discovery of the isostructural titanium-based single-crystals, ATi3Bi5 (A = K, Rb, Cs), which exhibit similar multiple exotic states but without the concomitant charge-density wave, has opened an opportunity to disentangle these complex states in kagome lattices. Here, we combine high-resolution angle-resolved photoemission spectroscopy and first-principles calculations to investigate the low-lying electronic structure of RbTi3Bi5. We demonstrate the coexistence of flat bands and several non-trivial states, including type-II Dirac nodal lines and $${{\mathbb{Z}}}_{2}$$ Z 2 non-trivial topological surface states. Our findings also provide evidence for rotational symmetry breaking in RbTi3Bi5, suggesting a directionality to the electronic structure and the possible emergence of pure electronic nematicity in this family of kagome compounds.

The North Pacific Subtropical Countercurrent area (STCC) is high in mesoscale eddy activities. According to the rotation direction of the eddy flow field and the sign of temperature anomaly within the eddy, they can be divided into four categories: cyclonic cold-core eddy (CCE), anticyclonic warm-core eddy (AWE), cyclonic warm-core eddy (CWE) and anticyclonic cold-core eddy (ACE). CCE and AWE are called normal eddies, and CWE and ACE are named abnormal eddies. Based on the OFES data and vector geometry automatic detection method, we find that at the sea surface, the maximum monthly number of the CCE, AWE, CWE, and ACE occurs in December (765.70 ± 52.05), January (688.20 ± 82.53), August (373.40 ± 43.09) and August (533.00 ± 56.92), respectively. The number of normal eddies is more in winter and spring, and less in summer and autumn, while abnormal eddies have the opposite distribution. The maximum rotation velocity of the four types of eddies appears in June (11.71 ± 0.75 cm/s), June (12.24 ± 0.86 cm/s), May (10.63 ± 0.99 cm/s) and June (9.97 ± 0.91 cm/s), which is fast in winter and spring. The moving speed of the four types of eddies is almost similar (about 10 ~ 11 cm/s). The amplitude of normal and abnormal eddies is both high in summer and autumn, and low in winter and spring, with larger amplitudes in normal than abnormal eddies. The eccentricity (defined as the eccentricity of the ellipse obtained by fitting the eddy boundary) of the four types of eddies is also close to each other, and their variation ranges from 0.7 to 0.8, with no apparent seasonal variation. The vertical penetration depth, which has no significant seasonal difference, is 675.13 ± 67.50 m in cyclonic eddies (CCE and CWE), which is deeper than that 622.32 ± 81.85 m in anticyclonic eddies (ACE and AWE). In addition, increasing the defined temperature threshold for abnormal eddies can significantly reduce their numbers but does not change their seasonal variation trend.

The North Pacific Subtropical Countercurrent (STCC) region has high mesoscale eddy activities due to its complex circulation structure. This study divides these mesoscale eddies into four types: cyclonic cold-core eddy (CCE), anticyclonic warm-core eddy (AWE), cyclonic warm-core eddy (CWE), and anticyclonic cold-core eddy (ACE) according to the rotation direction of the eddy flow field and the sign of average temperature anomaly within the eddy after spatial high-pass filtering. CCE and ACE are called normal eddies, while CWE and ACE are named abnormal eddies. Using eddy-resolving model data (OFES), this work finds that the abnormal eddy phenomenon mainly occurs in the ocean’s upper layer. The eddy number proportion for CCEs, AWEs, CWEs, and ACEs at the sea surface is 35.60, 32.08, 12.95, and 19.37%. The corresponding average radius is 79.14 ± 3.7, 83.34 ± 3.75, 73.74 ± 4.14, and 79.46 ± 3.89 km, respectively. Each type of eddy’s average amplitude is about 3 cm. Regarding the eddy average eccentricity, the four types of eddies have very close eccentricities, with a range of 0.73 ~ 0.76. If the types of eddies are not distinguished, the eddies generated north of 21°N tend to move southward, while eddies generated south of that latitude tend to move northward. The depth of CCEs, AWEs, CWEs, and ACEs with average eddy nonlinearity larger than one is concentrated in the ocean’s upper layer at 109.0, 116.0, 159.0, and 52.0 m, respectively. This study deepens the understanding of the spatial distribution characteristics of mesoscale eddies in the STCC region.

Oceanic mesoscale cyclonic (anticyclonic) eddies usually have cold (warm) cores and counterclockwise (clockwise) flow fields in the Northern Hemisphere. However, “abnormal” cyclonic (anticyclonic) eddies with warm (cold) cores and counterclockwise (clockwise) flow fields have recently been identified in the Kuroshio-Oyashio Extension (KOE) region. Here, traditional cyclonic cold-core eddies (CCEs) and anticyclonic warm-core eddies (AWEs) are termed normal eddies, and cyclonic warm-core eddies (CWEs) and anticyclonic cold-core eddies (ACEs) are called abnormal eddies. Applying a vector geometry-based automatic eddy detection method to the Ocean General Circulation Model for the Earth Simulator reanalysis data (OFES), a three-dimensional eddy dataset is obtained and used to quantify the statistical characteristics of these eddies. Results illustrate that the number of CCEs, AWEs, CWEs, and ACEs accounted for 38.46, 36.15, 13.40, and 11.99%, respectively. In the vertical direction, normal eddies are concentrated in the upper 2,000 m, while abnormal eddies are mainly found in the upper 600 m of the ocean. On seasonal scales, normal eddies are more abundant in winter and spring than in summer and autumn, with the opposite trend found for abnormal eddies. Potential density changes modulated by normal eddies are dominated by eddies-induced temperature anomalies, while salinity anomalies dominate the changes modulated by abnormal eddies. This study expands the types of eddies and enriches their understanding in the KOE region.

Abstract Fundamental understanding and control of the electronic structure evolution in rare‐earth nickelates is a fascinating and meaningful issue, as well as being helpful to understand the mechanism of recently discovered superconductivity. Here the dimensionality effect on the ground electronic state in high‐quality (NdNiO3) m/(SrTiO3)1 superlattices is systematically studied through transport and soft X‐ray absorption spectroscopy. The metal‐to‐insulator transition temperature decreases with the thickness of the NdNiO3 slab decreasing from bulk to 7 unit cells, then increases gradually as m further reduces to 1 unit cell. Spectral evidence demonstrates that the stabilization of insulating phase can be attributed to the increase of the charge‐transfer energy between O 2p and Ni 3d bands. The prominent multiplet feature on the Ni L3 edge develops with the decrease of NdNiO3 slab thickness, suggesting the strengthening of the charge disproportionate state under the dimensional confinement. This work provides convincing evidence that dimensionality is an effective knob to modulate the charge‐transfer energy and thus the collective ground state in nickelates.

Coal permeability measurements are normally conducted under the assumption that gas pressure in the matrix is equalized with that in fracture and that gas sorption-induced swelling/shrinking strain is uniformly distributed within the coal. However, the validity of this assumption has long been questioned and differential strain between the fracture strain and the bulk strain has long been considered as the primary reason for the inconsistency between experimental data and poroelasticity solutions. Although efforts have been made to incorporate the impact into coal permeability models, the fundamental nature of those efforts to split the matrix strain between fracture and coal bulk remains questionable. In this study, a new concept of differential swelling index (DSI) was derived to theoretically define the relation among sorption-induced strains of the coal bulk, fracture, and coal matrix at the equilibrium state. DSI was a function of the equilibrium pressure and its magnitudes were regulated by the Langmuir constants of both the matrix and the coal bulk. Furthermore, a spectrum of DSI-based coal permeability models was developed to explicitly consider the effect of differential strains. These models were verified with the experimental data under the conditions of uniaxial strain, constant confining pressure, and constant effective stress.

Abstract Many widely used reservoir simulators include an EOR option, but there is no feature available in a commercial simulator in the oil industry that simulates microbial enhanced oil recovery (MEOR) process. Eclipse, one of the popular reservoir simulators, does not have this option. In this study the Eclipse reservoir simulator has been modified and used to simulate MEOR core-flooding experiments. The combined effects on oil recovery of anionic surfactants and alcohol, nonionic surfactants and alcohol, and anionic and nonionic surfactants blended with alcohol are examined. A commercial Eclipse simulator was modified to add the option to simulate a MEOR process as this was not available. The modified simulator was used to simulate three core-flood experiments with three formulations. The JF-2 bio-surfactant and butanol solution core-flood test was simulated. The result was slightly higher than the experimental result but compared reasonably well. The simulated tertiary and total oil recoveries of the APG and butanol solution were similar to the experimental values: the simulated TOR and total recovery were 41% and 81%, respectively, while the core-flooding TOR and total recovery were 41% and 82%. The APG, bio-surfactant and butanol combination core-flood experiment, when simulated, produced an oil recovery curve that was a reasonable match with the experimental curve.

CO2 injection into coal seam triggers a series of processes that are coupled all together through a permeability model. Previous studies have shown that current permeability models cannot explain experimental data as reported in the literature. This knowledge gap defines the goal of this study. We hypothesize that this failure originates from the assumption that the pore strain is the same as the bulk strain in order to satisfy the Betti-Maxwell reciprocal theorem. This assumption is valid only for the initial state without gas sorption and deformation and for the ultimate state with uniform gas sorption and uniform deformation within the REV (representative elementary volume). In this study, we introduce the pore-bulk strain ratio and interference time to characterize the process of gas sorption and its associated nonuniform deformation from the initial state to the ultimate state. This leads to a new nonequilibrium permeability model. We use the model to fully couple the coal deformation and gas flow. This new coupled model captures the impact of coal local transient behaviors on gas flow. Results of this study clearly show that coal permeability is constrained by the magnitudes of initial and ultimate pore-bulk strain ratios and interference time, that current permeability data in the literature are within these bounds, and that the evolutions of coal permeability all experience similar stages from the initial value to the ultimate one.

In the process of coalbed methane exploitation, the fracture and pore structure is the key problem that affects the permeability of coalbed. At present, the coupling effect of fracture and pore structure and in situ stress is seldom considered in the study of coal seam permeability. In this paper, the fractal seepage model is coupled with coal deformation, and the adsorption expansion effect is considered. A multifield coupling model considering the influence of matrix and fracture structure is established. Then, the influence of pore structure parameters of main fracture on macropermeability is analyzed, including (1) fractal dimension of fracture length, (2) maximum fracture length, (3) fractal dimension of throat diameter, and (4) fractal dimension of throat bending. At the same time, the simulation results are compared with the results of Darcy’s uniform permeability model. The results show that the permeability calculated by the proposed model is significantly different from that calculated by the traditional cubic model. Under the action of in situ stress, when the porosity and other parameters remain unchanged, the macropermeability of coal is in direct proportion to the fractal dimension of coal fracture length, the fractal dimension of throat diameter, and the maximum fracture length and in inverse proportion to the fractal dimension of coal throat curvature.

Bovine Escherichia coli infection, which causes major economic losses to the cattle industry each year, can be prevented by administering formalin-inactivated vaccine. However, to enhance the application of this vaccine, the cell density of the formalin-inactivated E. coli should be boosted. This can be achieved by reducing the accumulation of acetate, a primary inhibitory metabolite in E. coli fermentation. To this end, the present study investigated the effect of pH, dissolved oxygen (DO) levels, and feeding methods on bovine E. coli fermentation, and developed two-stage pH and DO control strategies and a combined pH- and DO-mediated feeding strategy for the fermentation. The optimized conditions for Bovine E. coli were pH 7.0 at 0-10 h, 6.5 at 10-24 h; DO 50% at 0-10 h, 30% at 10–24 h; pH and DO feedback feeding at 0-10 h and 10-24 h, respectively. With Bovine E. coli fermentation under the optimized conditions, the acetate accumulation was 1.12 g/L and the cell density was 36.47 (OD600), which were 59.12% lower and 77.29% higher than these with the original conditions (pH 7.0; DO 20%; residual glucose concentration maintained at 2.0 g/L). After analyzing the main nodes of acetate synthesis, it was found that the lower carbon flux enters the Embden-Meyerhof pathway. Under the optimized conditions, the pyruvate flux and acetyl-CoA synthesis were low, and much of the acetyl-CoA participated in the tricarboxylic acid cycle. The extracellular acetate flux was 8.3%, which was 65.13% lower than in the original conditions.

Abstract The perovskite oxide LaNiO3 is a promising oxygen electrocatalyst for renewable energy storage and conversion technologies. Here, it is shown that strontium substitution for lanthanum in coherently strained, epitaxial LaNiO3 films (La1−x SrxNiO3) significantly enhances the oxygen evolution reaction (OER) activity, resulting in performance at x = 0.5 comparable to the state‐of‐the‐art catalyst Ba0.5Sr0.5Co0.8Fe0.2O3−δ. By combining X‐ray photoemission and X‐ray absorption spectroscopies with density functional theory, it is shown that an upward energy shift of the O 2p band relative to the Fermi level occurs with increasing x in La1−xSrxNiO3. This alloying step strengthens Ni 3d–O 2p hybridization and decreases the charge transfer energy, which in turn accounts for the enhanced OER activity.

Shale gas reservoir is a typical type of unconventional gas reservoir, primarily because of the complex flow mechanism from nanoscale to macroscale. A triple-porosity model (M3 model) comprising kerogen system, matrix system, and natural fracture system was presented to describe the multispace scale, multitime scale, and multiphysics characteristic of gas flows in shale reservoir. Apparent permeability model for real gas transport in nanopores, which covers flow regime effect and geomechanical effect, was used to address multiscale flow in shale matrix. This paper aims at quantifying the shale gas in different scales and its sequence in the process of gas production. The model results used for history matching also showed consistency against gas production data from the Barnett Shale. It also revealed the multispace scale process of gas production from a single well, which is supplied by gas transport from natural fracture, matrix, and kerogen sequentially. Sensitivity analysis on the contributions of shale reservoir permeability in different scales gives some insight as to their importance. Simulated results showed that free gas in matrix contributes to the main source of gas production, while the performance of a gas shale well is strongly determined by the natural fracture permeability.

In this study, laboratory experiments are conducted to investigate the rapid decompression and desorption induced energetic failure in coal using a shock tube apparatus. Coal specimens are recovered from Colorado at a depth of 610 m. The coal specimens are saturated with the strong sorbing gas CO2 for a certain period and then the rupture disc is suddenly broken on top of the shock tube to generate a shock wave propagating upwards and a rarefaction wave propagating downwards through the specimen. This rapid decompression and desorption has the potential to cause energetic fragmentation in coal. Three types of behaviors in coal after rapid decompression are found, i.e. degassing without fragmentation, horizontal fragmentation, and vertical fragmentation. We speculate that the characteristics of fracture network (e.g. aperture, spacing, orientation and stiffness) and gas desorption play a role in this dynamic event as coal can be considered as a dual porosity, dual permeability, dual stiffness sorbing medium. This study has important implications in understanding energetic failure process in underground coal mines such as coal gas outbursts.

When gas is extracted from unconventional rock, local equilibrium conditions between matrixes and fractures are destroyed and significant local effects are introduced. Although the interactions between the matrix and fracture have a strong influence on the permeability evolution, they are not understood well. This may be the reason why permeability models in commercial codes do not include the matrix-fracture interactions. In this study, we introduced the local force to define the interactions between the matrix and the fracture and derived a set of partial differential equations to define the full coupling of rock deformation and gas flow both in the matrix and in the fracture systems. The full set of cross-coupling formulations were solved to generate permeability evolution profiles during unconventional gas extraction. The results of this study demonstrate that the contrast between the matrix and fracture properties controls the processes and their evolutions. The primary reason is the gas diffusion from fractures to matrixes. The diffusion changes the force balance, mass exchange and deformation.

On the basis of a large number of core and thin-section observations, the petrologic and pore evolution characteristics of welded tuffs in the Fengcheng Formation in the Wu-Xia area, Junggar Basin, are evaluated, and the genesis of vesicular welded tuffs and the formation mechanism of vesicles are analyzed. Volcanic activity in the Fengcheng Formation is characterized by welded pyroclastic rocks. There are predominant plastic shards with rounded edges and obvious devitrification in the rocks. Plastic debris (fiamme) is commonly deformed and wrinkled, and crystal fragments are usually corroded. A lot of lithophysae occur in the welded tuffs, and the welded texture is obscured due to the occurrence of these lithophysae features. Vesicles are the cavities of lithophysae, which are formed by solidification contraction. They have little or no late filling cement because the volatile constituent and water vapour in the bubbles have escaped with the help of devitrification. Lithophysae distribution within a cooling unit are characterized by vertical zonation: increasing upwards but decreasing gradually later. The cavities of lithophysae have greatly improved the reservoir quality of welded tuffs. Influenced by the intensive welding process, lithophysae are not subject to collapse or damage. In the study area, deeply buried vesicular welded tuffs are important hydrocarbon reservoir rocks, and the vesicular welded tuff has good petroliferous properties. Key words: welded tuffs, vesicle, lithophysa, pyroclastic flow, Fengcheng Formation, Wu-Xia area, Junggar Basin

The water-enriched mined-out area, which led to frequent accidents and the serious destruction of ecological environment and serious threat to coal-mining practices. To ensure safe mining practices and to avoid the intrusion of water from the bases of coal deposits, the detection of the mined-out areas, especially the water-filled mined-out area in advanced, is one of the most important issues. This research focuses on detecting mined-out area enriched by water with the large-loop transient electromagnetic method. Data acquisition system was arranged along 23 survey lines, and the total of 1975 survey points were recorded. An inversion technique was used to interpret the TEM data. The inversion results suggested that the mined-out areas enriched by water always exhibit a very low-resistivity, the resistivity contour present closed circle sharp. There are three main water enriched mined-out areas, named JS1, JS2, and JS3 in the north part of the survey area, as well as three main water weak-enriched areas named RJS1, RJS2 and RJS3 in the west and southwest part of the survey area can be inferred by TEM, the interpretation results were verified by drilling. Large loop TEM is proved as an efficient way to investigate water enriched mined-out areas under the rugged topography conditions, and this work provides more detailed geological information to the coal mining enterprise for further coal-mining practices safety arrangement.

The evolution of coal permeability is vitally important for the effective extraction of coal seam gas. A broad variety of permeability models have been developed under the assumption of local equilibrium, i.e., that the fracture pressure is in equilibrium with the matrix pressure. These models have so far failed to explain observations of coal permeability evolution that are available. This study explores the evolution of coal permeability as a non-equilibrium process. A displacement-based model is developed to define the evolution of permeability as a function of fracture aperture. Permeability evolution is tracked for the full spectrum of response from an initial apparent-equilibrium to an ultimate and final equilibrium. This approach is applied to explain why coal permeability changes even under a constant global effective stress, as reported in the literature. Model results clearly demonstrate that coal permeability changes even if conditions of constant effective stress are maintained for the fracture system during the non-equilibrium period, and that the duration of the transient period, from initial apparent-equilibrium to final equilibrium is primarily determined by both the fracture pressure and gas transport in the coal matrix. Based on these findings, it is concluded that the current assumption of local equilibrium in measurements of coal permeability may not be valid.