Condensation Theory Research Articles

Heat transfer model based on diffusion layer theory for dropwise condensation with high non-condensable gas

A new heat-transfer model for dropwise condensation with non-condensable gas (NCG) is developed, which can be used in the design and calculations of a dehumidifier in humidification–dehumidification technology. A single-droplet heat-transfer model is established via the rounded analysis of all the contributing thermal resistances based on the diffusion-layer theory. Combined with the drop size distribution, the heat flux of dropwise condensation with NCG is determined, and the error between the predicted results and previous experimental data is found to be within ±20%. The effects of different parameters on the heat transfer of dropwise condensation with NCG are investigated, and the results indicate that there is an optimal contact angle to maximize the heat flux, which depends on the NCG content. The thickness of the coating layer has little effect on the heat flux at a given thermal conductivity of the coating layer, indicating that the dropwise condensation effect can be improved by increasing the thickness of the coating layer, neglecting the heat-transfer deterioration due to the additional thermal resistance during dropwise condensation with NCG.

Nonequilibrium molecular dynamics study on energy accommodation coefficient on condensing liquid surface—Molecular boundary conditions for heat and mass transfer

Nonequilibrium molecular dynamics (NEMD) studies have been conducted to determine molecular boundary conditions at vapor–liquid interfaces for the kinetic theory of condensation and evaporation. In previous studies, a microscopic formulation of the condensation coefficient was defined as the condensation probability of vapor molecules based on equilibrium molecular dynamics simulations and transition state theory. The condensation coefficient was presented as a function of the translation energy of incoming molecules and surface temperature. Based on this, the velocity distributions of evaporating and reflecting molecules were theoretically expressed under equilibrium conditions. In a practical nonequilibrium situation, the energy transfer by the reflecting molecules is important along with the condensation/evaporation probability. However, it is unclear whether the results obtained under equilibrium conditions can be applied under nonequilibrium conditions. This study, therefore, defines the energy accommodation coefficient of reflecting molecules by comparing the energy transfer due to reflection with that under equilibrium conditions. NEMD simulations are conducted using two surfaces facing each other, an evaporating surface and a condensing surface, for argon molecules under different nonequilibrium conditions. The results show that the velocity distribution of reflecting molecules deviates from those under equilibrium conditions, and the energy accommodation coefficient decreases as nonequilibrium conditions increase. Additionally, an inverted temperature profile is observed. Reflecting molecules play an important role in the sensible heat transfer on the condensing surface, and they are not accommodated on the condensing surface. Thus, they raise the temperature in the vicinity of the condensing surface under nonequilibrium conditions.

Universal T/B Scaling Behavior of Heavy Fermion Compounds (Brief Review)

In our mini-review, we address manifestations of $T/B$ scaling behavior of heavy-fermion (HF) compounds, where $T$ and $B$ are respectively temperature and magnetic field. Using experimental data and the fermion condensation theory, we show that this scaling behavior is typical of HF compounds including HF metals, quasicrystals, and quantum spin liquids. We demonstrate that such scaling behavior holds down to the lowest temperature and field values, so that $T/B$ varies in a wide range, provided the HF compound is located near the topological fermion condensation quantum phase transition (FCQPT). Due to the topological properties of FCQPT, the effective mass $M^*$ exhibits a universal behavior, and diverges as $T$ goes to zero. Such a behavior of $M^*$ has important technological applications. We also explain how to extract the universal scaling behavior from experimental data collected on different heavy-fermion compounds. As an example, we consider the HF metal $\rm YbCo_2Ge_4$, and show that its scaling behavior is violated at low temperatures. Our results obtained show good agreement with experimental facts.

Theory of photon condensation in a spatially varying electromagnetic field

The realization of equilibrium superradiant quantum phases (photon condensates) in a spatially-uniform quantum cavity field is forbidden by a "no-go" theorem stemming from gauge invariance. We here show that the no-go theorem does not apply to spatially-varying quantum cavity fields. We find a criterion for its occurrence that depends solely on the static, non-local orbital magnetic susceptibility $\chi_{\rm orb}(q)$, of the electronic system (ES) evaluated at a cavity photon momentum $\hbar q$. Only 3DESs satisfying the Condon inequality $\chi_{\rm orb}(q)>1/(4\pi)$ can harbor photon condensation. For the experimentally relevant case of two-dimensional (2D) ESs embedded in quasi-2D cavities the criterion again involves $\chi_{\rm orb}(q)$ but also the vertical size of the cavity. We use these considerations to identify electronic properties that are ideal for photon condensation. Our theory is non-perturbative in the strength of electron-electron interaction and therefore applicable to strongly correlated ESs.

Non-intrusive reduced order modelling for the dynamics of geometrically nonlinear flat structures using three-dimensional finite elements

Non-intrusive methods have been used since two decades to derive reduced-order models for geometrically nonlinear structures, with a particular emphasis on the so-called STiffness Evaluation Procedure (STEP), relying on the static application of prescribed displacements in a finite-element context. We show that a particularly slow convergence of the modal expansion is observed when applying the method with 3D elements, because of nonlinear couplings occurring with very high frequency modes involving 3D thickness deformations. Focusing on the case of flat structures, we first show by computing all the modes of the structure that a converged solution can be exhibited by using either static condensation or normal form theory. We then show that static modal derivatives provide the same solution with fewer calculations. Finally, we propose a modified STEP, where the prescribed displacements are imposed solely on specific degrees of freedom of the structure, and show that this adjustment also provides efficiently a converged solution.

Condensation Energy in a Superconductor for All Temperatures

An exact analytical expression for the condensation energy $$E_{\text{cond}} \left( T \right)$$ of a phonon-driven superconductor for all absolute temperatures $$T$$ and for any coupling strength is introduced so as to calculate the Helmholtz free energy difference $$F_{s} \left( T \right) - F_{n} \left( T \right)$$ between superconducting $$\left( s \right)$$ and normal $$\left( n \right)$$ states. This is achieved via a boson–fermion ternary gas theory—called the generalized Bose–Einstein condensation (GBEC) theory—which includes two-hole Cooper pairs, two-electron ones as well as single, free/unbound electrons. The GBEC formalism turns out to be quite useful in dealing with nonzero $$T$$ values of $$E_{\text{cond}} \left( T \right)$$ and reproduces several well-known experimental results. An expression for the condensation energy per atom is also calculated and applied to aluminum and niobium, and both results are compared with experimental data.

Flue Gas Water Recovery by Indirect Cooling Technology for Large-Scale Applications: A Review

With social development and economic enhancement, energy is facing significant worldwide demand, and fossil fuels are the prime energy sources for various energy systems over past decades. Furthermore, among fuel-consumed applications, power plants are the primary source of energy consumption. There is a lot of waste heat and steam accompanied by the latent heat produced in the exhaust flue gas. Therefore, the latent heat recovery from the flue gas plays an important role in increasing the efficiency of the system and saving water. To recover the heat and mass in power plants, three primary methods are proposed to condense the vapor based on previous studies: (1) flue gas condensation technology, (2) liquid desiccant-based dehydration (LDD) technology and (3) membrane technology. This paper mainly reviews and summaries the indirect cooling technology in flue gas condensation technology. The numerical simulation and theory of flue gas condensation are introduced. Different heat exchanger types and conducted experiments are also summarized. The performance of the indirect cooling technology is affected not only by its own configuration and design but also by the flue gas inlet temperature, velocity, water vapor mass fraction, etc. The major concerns and outlook of practical applications for further study are attributed to the heat exchanger size and cost, acid corrosion, ash accumulation in flue gas, etc.

Contributions and competition of Mg2+ and K+ in folding and stabilization of the Twister ribozyme.

Native folded and compact intermediate states of RNA typically involve tertiary structures in the presence of divalent ions such as Mg2+ in a background of monovalent ions. In a recent study, we have shown how the presence of Mg2+ impacts the transition from partially unfolded to folded states through a “push-pull” mechanism where the ion both favors and disfavors the sampling of specific phosphate-phosphate interactions. To further understand the ion atmosphere of RNA in folded and partially folded states results from atomistic umbrella sampling and oscillating chemical potential grand canonical Monte Carlo/molecular dynamics (GCMC/MD) simulations are used to obtain atomic-level details of the distributions of Mg2+ and K+ ions around Twister RNA. Results show the presence of 100 mM Mg2+ to lead to increased charge neutralization over that predicted by counterion condensation theory. Upon going from partially unfolded to folded states, overall charge neutralization increases at all studied ion concentrations that, while associated with an increase in the number of direct ion-phosphate interactions, is fully accounted for by the monovalent K+ ions. Furthermore, K+ preferentially interacts with purine N7 atoms of helical regions in partially unfolded states, thereby potentially stabilizing the helical regions. Thus, both secondary helical structures and formation of tertiary structures leads to increased counterion condensation, thereby stabilizing those structural features of Twister. Notably, it is shown that K+ can act as a surrogate for Mg2+ by participating in specific interactions with nonsequential phosphate pairs that occur in the folded state, explaining the ability of Twister to self-cleave at submillimolar Mg2+ concentrations.

Sorption and diffusion of organic acid ions in anion exchange membranes: Acetate and lactate ions as a case study

In this study, the sorption behaviour and conductivity of two anion exchange membranes (AR103 and AR204) equilibrated with sodium acetate and sodium lactate solutions are studied across a range of concentrations and pH values. The results indicate that the dissociation equilibria of the organic acids differ between the membrane phase and the external solution. There are significant concentrations of the neutral organic acid in the membranes at pH 6.5 even though the dissociation is virtually complete in the external solution. The concentration of this neutral acid increases as the pH is lowered, leading to a reduction in membrane conductivity. The diffusion coefficients of acetate and lactate ions in these membranes are determined from conductivity data. The results show that these diffusion coefficients are relatively constant but decrease slightly with an increase of external solution concentration due to osmotic deswelling. The diffusion coefficient of the acetate anion decreases as the pH falls, possibly due to dimer formation. Models extended from Manning's condensation theory have been utilized in the prediction of the co-ion concentrations within the membrane and the diffusion coefficients of the lactate and acetate anions. There is an excellent agreement between the experimental values of these parameters and the model predictions for the sodium lactate system but the model is unable to accurately fit the sodium acetate data.

Partial Pinning Control for the Synchronization of Fractional-Order Directed Complex Networks

This paper mainly studies the synchronization problem of fractional-order directed complex networks through partial pinning control. Unlike other papers, the network studied in this paper is neither strongly connected nor contains directed spanning trees. By utilizing the directed acyclic graph condensation and Layering theory, the network is decomposed into several strong connected components and then divided into layers. It proved that all or part of nodes in the network can achieve synchronization with the pinner’s trajectory, only when the root strong connected components in the upstream of these nodes are pinned and satisfy some sufficient conditions. In addition, according to the ControlRank algorithm, an optimized strategy is designed to solve the problem of the optimal selection of the pinning nodes to ensure the specific nodes of the network can achieve synchronization eventually. Meanwhile the amount of control energy cost will also be given in this paper. Finally, two simulation examples are given to verify the reliability and feasibility of the optimized algorithm.

Modeling and validation of concentration dependence of ion exchange membrane permselectivity: Significance of convection and Manning's counter-ion condensation theory

Electrodialysis, reverse electrodialysis, and related electrochemical processes are increasingly important technologies for water purification and renewable energy generation and storage. The electrical efficiency of these processes is directly related to the permselectivity of the ion exchange membranes (IEMs) – defined as the extent to which the membrane permits the passage of counter-ions (ions of opposite charge to the membrane, e.g., cations for a cation exchange membrane) while blocking passage of co-ions. Permselectivity is not a material constant, but rather depends on the concentration and composition of the electrolyte solutions in contact with the IEM. Thus, even though permselectivity is routinely measured at standardized conditions (usually 0.5 M/0.1 M NaCl or KCl), the practical utility of such data is limited because we lack an accurate, quantitative way of using it to predict permselectivity under relevant process conditions. Moreover, the concentration dependence of IEM permselectivity has historically been studied primarily by evaluating the performance of (reverse) electrodialysis stacks rather than individual membranes, which has made it difficult to relate the concentration dependence of permselectivity to specific membrane characteristics. In this study, we measured the permselectivity of four commercial IEMs in six different concentration gradients employing 4 M and 0.5 M NaCl as the high salt concentration. We then constructed a predictive model of membrane permselectivity based on the extended Nernst-Planck equation and investigated how accounting for convection and electrostatic effects (via Manning's counter-ion condensation theory) affected model accuracy. We demonstrate that accurate, quantitative predictions of IEM permselectivity as a function of external salt concentrations are possible and require knowledge of only four easily measured membrane properties: water uptake, water permeability, charge, and thickness.

Theoretical Study and calculation The cold Reaction Rate of Deuteron Fusion In Nickel Metal Using Bose–Einstein Condensate Theory

In this paper, we focused on the investigated and studied the cold fusion reaction rate for D-D using the theory of Bose-Einstein condensation and depending on the quantum mechanics consideration. The quantum theory was based on the concept of single conventional of deuterons in Nickel-metal due to Bose-Einstein condensation, it has supplied a consistent description and explained of the experimental data. The analysis theory model has capable of explaining the physical behaviour of deuteron induced nuclear reactions in Nickel metals upon the five-star matter, it‘s the most expected for a quantitative predicted of the physical theory. Based on the Bose-Einstein condensation theorem formulation, we calculation the cold fusion reaction rate for D-D transfer to Nickel-metal using the astrophysical S factors (S = 110KeV — barn) for d(d,p)T, d(d, n)3He reactions and (S = 110 × 106 and S = 110 × 1013KeV — barn) for D + D × 4 He + 23.8MeV reaction. The results of the calculation for three reactions give rise a wide compatible with the other experimental works.

Dynamics of thermophysical parameters of silver ablation jets at atmospheric pressure

The paper demonstrates an approach to modeling the thermophysical parameters of vapor in an ablative silver jet propagating at atmospheric pressure. The proposed semi-empirical model is based on the modification of the Anisimov – Luk’yanchuk model taking into account the Zeldovich – Raiser dynamic condensation theory. Such process of dynamic condensation of spherical (or semi-spherical) ablative jets can also be graphically represented as passing in the expanding vapor-plasma cloud of the three spatial concentric spherical waves from the periphery to the center of cloud. There are «saturation» wave (corresponding to the moment of crossing the Poisson adiabate with saturation adiabate at the phase diagram of vapor), wave of nuclear «etching» (the moment of greatest supercooling of vapor in the jet) and the «quenching» wave (stabilization of the condensation degree of the vapor in the jet). Due to the revision of a number of basements of the Anisimov – Luk’yanchuk model, it was possible to offer an adequate description of thermodynamic processes occurring at normal atmospheric gas pressure.

Studying physiology within a flipped classroom: The importance of on-campus activities for nursing students' experiences of mastery.

To explore the on-campus activities of the flipped classroom and their role in nursing students' experiences of mastering physiology. A nurse must be confident in their knowledge of physiology to feel confident as a nurse. However, many nursing students do not believe in their ability to master physiology. The flipped classroom design could facilitate active learning and promote students' confidence and competence in physiology. A design-based research design was employed. Twenty-three nursing students enrolled in an anatomy and physiology course participated in two focus group interviews and wrote two individual reflective notes. The data were analysed by means of systematic text condensation and activity theory. Reporting was guided by the Consolidated Criteria for Reporting Qualitative Studies (COREQ). The study findings underscore the importance of careful design of on-campus activities within the flipped classroom to support students' experiences of mastery in physiology. Four themes were identified: (a) preparation which builds a foundation for learning; (b) the use of digital tools; (c) learning through dialogue with peers; and (d) experience of the expected learning outcomes. On-campus learning activities within a flipped classroom design could support students' experiences of confidence in and mastery of physiology. However, the study participants found learner-centred activities challenging and described feeling doubtful of their ability to master physiology. A didactic framework could take into account the circumstance that students perceive educational technology differently. When designing on-campus activities, emphasis should be placed on collaboration rather than competition to help students develop confidence in their knowledge of physiology. It is important to support nursing students' knowledge acquisition in bioscience and their development of confidence as these skills could enhance their clinical judgment in practice. Comprehension of bioscience is necessary to provide safe patient care and competent nursing.

Review and prospect of fog elimination technology based on acoustic condensation

This paper summarizes the traditional artificial fog elimination technology and the principle and mechanism of acoustic condensation theory, reviews the simulation experiment research and application of acoustic condensation fog elimination technology. Compared with traditional fog elimination technology, sum up the advantages and disadvantages of acoustic condensation fog elimination technology. Put forward the existing problems and future research direction of acoustic condensation fog elimination field.

Advances in vapor dropwise condensation heat transfer

Vapor condensation on solid surface is widely observed in nature and employed in industry, among which, dropwise condensation (DWC) has attracted a lot of attentions due to its high performance in heat transfer and wide applications in industries. With remarkable advances in functional surface engineering, more and more progresses have been obtained in this field. Therefore, it is necessary to carry a review for those investigations obtained by different methods and on various aspects of DWC. An introduction of the wetting of droplets is firstly presented, and then this review article turns to theoretical modelling of heat transfer, followed by numerical and experimental works. No doubt that it is impossible to cover all the efforts since 1930, when DWC was observed for the first time. Thus, the present work is mainly devoted to delivering two issues, by summarizing several representative questions. One is the origin of classical heat transfer model and the other is a framework of DWC research. The wetting of both macro-droplets and nano-droplets matters significantly in the whole life of a condensed droplet. For the former, contact angle and wetting status are introduced, while for the latter, three hypotheses for nano-droplet formation are responded. “The hypothesis of film break-up” has been abandoned; the widely accepted “hypothesis of specific nucleation cites” is demonstrated here based on solid evidence from molecular dynamics (MD) simulations. To be honest, it is not easy to sufficiently abandon “the hypothesis of coexistence of droplet and film”, which may still be regarded as an open question. For heat transfer modelling, via a comparison with Nusselt’s theory of filmwise condensation, it is shown that heat transfer modelling for DWC, as a challenging topic, is remarkably different from those for convention heat transfer, or even filmwise condensation. The development of this topic presents a long story. The efforts in early stage are devoted to understanding basic mechanisms and improving measurement accuracy. With the advances in superhydrophobic surfaces, the enhancement of DWC is obtained by advanced manipulation of condensed droplets wetting, especially by efficient removal of condensed droplets. These works are divided into three types according to the differences in their motivations: For accurately modelling of solid-liquid interaction, for the effect of coalescence-induced droplet jumping, and for new-facing situations of industry applications. To optimize DWC, it is necessary to sufficiently understand its mechanism of droplet wetting, which is mainly performed by numerical simulations, especially by MD simulation method and lattice Boltzmann method (LBM). Before a summary of the latter one, the contribution of MD simulations is credited by presenting their exploration on the fundamental behaviours of condensed nano-droplets, especially the formation, wetting, growth, coalescence and self-driven departures. The efforts and advances above are actually inspired by, and will be applied to as well, experimental investigations. Firstly, a summary is given for the coating techniques for super-hydrophobic surfaces, with some comments. Then, the development of experimental work is presented by dividing its history into three stages: Initial pioneering for mechanism and measurement, coating-inspired DWC, and interdiscipline-boosted DWC. The advances of DWC with non-condensable gas are introduced as well, which is expected to help DWC be applied extensively. Finally, a summary of the progresses and possible challenges are given, followed by the advices on several specific questions. Our revisit to “the DWC museum” is concluded by an outlook full of promise, with the application of emerging technologies in this classical field.

Flat Bands and Salient Experimental Features Supportingthe Fermion Condensation Theory of Strongly Correlated Fermi Systems

The physics of strongly correlated Fermi systems, being the mainstream topic for more than half a century, still remains elusive. Recent advancements in experimental techniques permit to collect important data, which, in turn, allow us to make the conclusive statements about the underlying physics of strongly correlated Fermi systems. Such systems are close to a special quantum critical point represented by topological fermion-condensation quantum phase transition which separates normal Fermi liquid and that with a fermion condensate, forming flat bands. Our review paper considers recent exciting experimental observations of universal scattering rate related to linear temperature dependence of resistivity in a large number of strongly correlated Fermi systems as well as normal metals. We show that the observed scattering rate is explained by the emergence of flat bands, while the so-called Planckian limit occurs accidentally since the normal metals exhibit the same scattering rate behavior. We also analyze recent challenging experimental data on tunneling differential conductivity collected under the application of magnetic field on the twisted graphene and the archetypical heavy fermion metal YbRh $${}_{2}$$ Si $${}_{2}$$ . Also we describe recent empirical observations of scaling properties related to universal linear-temperature resistivity for a large number of strongly correlated high-temperature superconductors. We show that these observations support the fermion condensation theory. Our theoretical results are in good agreement with corps of different and seemingly unrelated experimental facts. They show that the fermion-condensation quantum phase transition is an intrinsic property of strongly correlated Fermi systems and can be viewed as the universal agent explaining their core physics.

The perception gap: how the benefits and harms of cervical cancer screening are understood in information material focusing on informed choice

The benefits and harms of cervical cancer screening are delicately balanced, and in that sense, many argue that participation should be based on an informed choice. Information pamphlets play a central part in the process of obtaining informed consent from women, and therefore adequate communication about health and risk is essential. However, pamphlets on screening have been shown to be information poor and biased in favour of participation, and little attention has been paid to how the pamphlets are understood. The aim of this study was twofold: 1) to develop evidence-based information material on cervical cancer screening; and 2) to investigate how women understand and interpret this information. We carried out semi-structured interviews with 17 women aged 23–55 in two interview rounds. We analysed the transcribed interviews using meaning condensation theory, which we followed with a second order analysis guided by approaches to cognitive dissonance. Generally, we found that the newly developed information succeeded in presenting understandable health and risk information on cervical cancer screening. Participants, however, still sometimes struggled with understanding the numerical risk and their preconceptions about screening led them to focus on the benefits and downplay the harms. According to cognitive dissonance theory, our second finding points to the use of defence mechanisms which create a perception gap between the written information and the participants’ understanding of the information. We conclude by arguing that breaching the perception gap is necessary if we want to increase possibilities for making an informed choice about participation in cervical cancer screening.

Mesoporous polymer systems based on divinylbenzene copolymers modified with linear rubbers

Porous polymer systems based on divinylbenzene copolymers modified with co-monomers (ethylvinylbenzene, methyl acrylate, methacrylic acid) and linear rubber macromolecules (polybutadiene, polyisoprene, polyisobutylene, polystyrene-butadiene, polyacrylonitrile-butadiene) were investigated. The copolymers in the form of spherical beads were synthesized by radical suspension polymerization of monomer compositions with appropriate porogenic organic solvents. It was found that modification of the divinylbenzene copolymers by linear rubbers enables the synthesis of sorbents with a controlled fractional composition of micro- and mesopores. A universal method is suggested for a quantitative estimation of fractional pore size distribution in the range of micro and mesopores from the data of low-temperature nitrogen sorption. Calculations of integral and differential distributions are based on using methods of quenched solid density functional theory (QSDFT), non-local density functional theory and the Barrett-Joyner-Halenda method based on capillary condensation theory. According to QSDFT calculations, the porous system of sorbents contains three groups of pores of certain sizes: 1.7–3.3, 3.3–6.6 and 8.4–40 nm. Upon introduction of polyisoprene into the polymer system the sorbent containing primarily 8–24 nm mesopores is obtained; upon the introduction of polyisobutylene, the sorbent with pore sizes of 4–6 nm is synthesized. The volume and surface area of micropores in the copolymers with polyisoprene and polyisobutylene may be increased by extracting a part of the rubber phase with toluene. Specific surface area of the copolymers varies in the range of 230–570 m2 g−1. Scanning electron microscopy studies of the porous structure of the polymer systems showed that in the copolymers with polybutadiene the porous structure is formed by the aggregates of globules 20–60 nm. The copolymer with polyisobutylene has a 3D skeletal structure with 100–200 nm voids.

Distribution of sorbed water in the pore network of mudstones assessed from physisorption measurements

Abstract Nitrogen- and carbon dioxide physisorption isotherms were measured on three mudstone samples which were each moisture equilibrated to five different relative humidities (11, 32, 56, 75 and 97% RH at 303 K). Moisture equilibration was realized in desiccators using the deliquescent points of saturated salt solutions. Systematic testing and reproducibility tests indicate no pore structure alteration and validate the experimental approach. Traditional physisorption theories were employed for analysing the experimental data. The data reveals a decreasing trend in sorption capacity, Gurvich total pore volume, in the specific surface area from the Brunauer-Emmett-Teller theory and in the limiting micropore volume from the Dubinin-Astakhov theory. A combination of Barrett-Joyner-Hallenda and Dubinin-Astakhov theory was applied to compute cumulative pores size distributions disclosing that preadsorbed water is located in pore throats or narrow mesopores. However, no direct correlation between pore size and relative humidity is observed for relative humidities below 97%, suggesting no singular pore size control with respect to sorption mechanism. This contradicts the capillary condensation theory of water in which pores fill sequentially but supports the assumption that water sorption in mudstones is rather surface chemistry controlled. Discrepancies between the loss of Gurvich total pore volume caused by the adsorption of water and the volume of the adsorbed water itself were identified and denote that some of the preadsorbed water is located in parts of the pore system which are not accessible by nitrogen. Water sorption into the interlayers of expandable clay minerals may provide an explanation for the observed volume imbalances, as calculated interlayer water volumes, are within in the same order of magnitude as the volume imbalance. Carbon dioxide physisorption isotherms of moisture equilibrated mudstones show the same decreasing trend in sorption capacity and limiting micropore volume as the nitrogen physisorption isotherms.