Porous Form Research Articles

Математическое моделирование напряженно-деформированного состояния в металлических средах на основе концепции силовых линий

В данной статье на базе классических работ Г.~Кирша, \textit{К. Inglis}, Г.~В.~Колосова, Н.~И.~Мусхелишвили в рамках теории упругости и линейной механики разрушения продолжена разработка математического аппарата, который позволяет получать решения ряда трёхмерных задач механики разрушения в упрочнённой металлической среде.Опираясь на работы \textit{G. R. Irwin}, Г.~И.~Баренблатта, Вестергарда (\textit{Westergaard}), Л.~Д.~Ландау, Е.~М.~Лившица авторы выполнили математическое моделирование напряженно"=деформированного состояния в объёме нагруженного стального образца в окрестностях пор различной морфологии, возникающих в результате эксплуатационных нагрузок и агрессивных воздействий окружающих сред.Привлечение авторами представлений о силовых линиях поля напряжений в металлической среде позволило им разработать алгоритм определения компонент тензора напряжений около концентраторов в виде пор различной формы. Был рассмотрен стационарный случай при фиксированном соотношении величин внешнего напряжения и предела текучести металлической среды (стали). Разработана методика и создан математический аппарат для расчёта уравнений силовых линий для трёхмерного случая - «поры в форме сферической линзы». Предлагаемый подход подтвердил наличие в окрестностях поры зон, свободных от напряжений, и выявил связь их размеров с морфологией пор и внешним напряжением.

Structural insights into loss of function of a pore forming toxin and its role in pneumococcal adaptation to an intracellular lifestyle.

The opportunistic pathogen Streptococcus pneumoniae has dual lifestyles: one of an asymptomatic colonizer in the human nasopharynx and the other of a deadly pathogen invading sterile host compartments. The latter triggers an overwhelming inflammatory response, partly driven via pore forming activity of the cholesterol dependent cytolysin (CDC), pneumolysin. Although pneumolysin-induced inflammation drives person-to-person transmission from nasopharynx, the primary reservoir for pneumococcus, it also contributes to high mortality rates, creating a bottleneck that hampers widespread bacterial dissemination, thus acting as a double-edged sword. Serotype 1 ST306, a widespread pneumococcal clone, harbours a non-hemolytic variant of pneumolysin (Ply-NH). Performing crystal structure analysis of Ply-NH, we identified Y150H and T172I as key substitutions responsible for loss of its pore forming activity. We uncovered a novel inter-molecular cation-π interaction, governing formation of the transmembrane β-hairpins (TMH) in the pore state of Ply, which can be extended to other CDCs. H150 in Ply-NH disrupts this interaction, while I172 provides structural rigidity to domain-3, through hydrophobic interactions, inhibiting TMH formation. Loss of pore forming activity enabled improved cellular invasion and autophagy evasion, promoting an atypical intracellular lifestyle for pneumococcus, a finding that was corroborated in in vivo infection models. Attenuation of inflammatory responses and tissue damage promoted tolerance of Ply-NH-expressing pneumococcus in the lower respiratory tract. Adoption of this altered lifestyle may be necessary for ST306 due to its limited nasopharyngeal carriage, with Ply-NH, aided partly by loss of its pore forming ability, facilitating a benign association of SPN in an alternative, intracellular host niche.

Post-processing ZnSe optical fibers with a micro-chemical vapor transport technique

Polycrystalline zinc selenide optical fibers and fiber lasers are expected to provide powerful capabilities for infrared waveguiding and laser technology. High pressure chemical vapor deposition, which is the only technique currently capable of producing zinc selenide optical fibers, leaves a geometric imperfection in the form of a central pore which is detrimental to mode quality. Chemical vapor transport with large temperature and pressure gradients not only fills this central pore but also encourages polycrystalline grain growth. Increased grain size and a reduction in defects such as twinning are demonstrated with transmission electron microscopy, Raman spectroscopy, and X-ray diffraction, supporting that high-quality material is produced from this method. Finally, the mode structure of the waveguide is improved allowing most of the guided optical intensity to be centrally positioned in the fiber core. Loss as low as 0.22 dB/cm at 1908nm is demonstrated as a result of the material improvement.

Основные пути создания пористых композиционных материалов

This paper is devoted to an overview of the main ways of creating porous composite materials. Porous materials are solids containing free space in the form of cavities, channels, or pores, which determine the presence of an internal interfacial surface. The analysis of the general methods of obtaining porous materials. A deposition is one of the most common methods for producing porous materials. Thermal decomposition, as a method used to obtain porous oxide materials by thermal decomposition of various compounds. Hydrothermal synthesis is widely used to produce zeolites. Selective dissolution of individual components of a substance using chemical reactions is also one of the effective methods for creating or increasing porosity. The paper discusses the methods of forming highly porous refractory materials. There are two main ways of forming refractory ceramic products. The first way is the direct sintering of dispersions of ceramic fibers. The second method is the use of a binder, which can significantly reduce the temperature of obtaining a porous product. The possibilities of obtaining porous nanocomposites based on aerogels are shown. Composite materials are usually obtained by combining two different materials. In general, the creation of composites is used to take advantage of each type of material and to minimize their disadvantages. Aerogels are fragile substances. But with the introduction of another component into their structure, it is possible to increase the strength of the material. Such materials have the desired optical properties, high surface area, and low density like silica aerogel. A review of methods for obtaining porous materials using the phenomenon of spinodal decomposition has been carried out. Materials whose structure is formed in microphase separation during polymerization or polycondensation have high permeability and a sufficiently large specific surface. A significant advantage of such materials is high porosity, which can reach 80% or more

In silico identification of Tretinoin as a SARS-CoV-2 envelope (E) protein ion channel inhibitor

Viroporins are oligomeric, pore forming, viral proteins that play critical roles in the life cycle of pathogenic viruses. Viroporins like HIV-1 Vpu, Alphavirus 6 K, Influenza M2, HCV p7, and Picornavirus 2B, form discrete aqueous passageways which mediate ion and small molecule transport in infected cells. The alterations in host membrane structures induced by viroporins is essential for key steps in the virus life cycle like entry, replication and egress. Any disruption in viroporin functionality severely compromises viral pathogenesis. The envelope (E) protein encoded by coronaviruses is a viroporin with ion channel activity and has been shown to be crucial for the assembly and pathophysiology of coronaviruses. We used a combination of virtual database screening, molecular docking, all-atom molecular dynamics simulation and MM-PBSA analysis to test four FDA approved drugs - Tretinoin, Mefenamic Acid, Ondansetron and Artemether - as potential inhibitors of ion channels formed by SARS-CoV-2 E protein. Interaction and binding energy analysis showed that electrostatic interactions and polar solvation energy were the major driving forces for binding of the drugs, with Tretinoin being the most promising inhibitor. Tretinoin bound within the lumen of the channel formed by E protein, which is lined by hydrophobic residues like Phe, Val and Ala, indicating its potential for blocking the channel and inhibiting the viroporin functionality of E. In control simulations, tretinoin demonstrated a lower binding energy with a known target as compared to SARS-CoV-2 E protein. This work thus highlights the possibility of exploring Tretinoin as a potential SARS-CoV-2 E protein ion channel blocker and virus assembly inhibitor, which could be an important therapeutic strategy in the treatment for coronaviruses.

Formation process of paste HDN slurry in gravel stratum

At present, due to the complex geological conditions and long-distance drive, scheduled and unscheduled cutter head intervention maintenance during shield tunneling has become a major innovation in shield engineering in China. Therefore, paste HDN has been successfully applied to cutter head intervention under pressure, but corresponding research work on its film-forming mechanism and process is lacking. Film-forming experiments and theoretical analysis of the paste indicated that the film-forming process of the paste during gravel-stratum formation can be divided into two stages: Seepage blocking of the forming pore diameter and forming of a mud cake on the excavation surface. The seepage process was completed almost instantaneously, and the forming process of a 5–10 cm mud cake required 1–2 days. In addition, a mud diffusion model was established for investigating the mud infiltration process. The results of the aforementioned experiments were applied to the cutter head intervention of Guangzhou Metro and Lanzhou Metro, and this application ensured the efficient and safe completion of the intervention task.

Special aspects of the process of welding fixed joints between thin-walled heat pipes made of aluminum alloys for the ISS modules

The process of joining thin-walled small-diameter pipes made of aluminum alloys using welding has some special aspects to it. Volumetric analysis shows occurrence of welding defects in the form of cracks, pores and oxide inclusions that are inadmissible according to the requirements of technical standards. This paper discusses a process for welding heat pipes to be used in rocket and space hardware, as well as presents solutions for scientific and technological problems encountered in the course of their making, such as: • Methods of preparing parts for welding and the process of welding composite members of heat pipe structure made of aluminum alloys with the use of special tooling; • An illustrative example of using effective creative assembly of pipes for welding with the use of a coolant which provides additional removal of heat from the area of the welded joint; • A well-chosen automated mode of welding fixed joints between thin-walled pipes using modern main and auxiliary welding materials and an inert protective gas that has a high degree of purification owing to a reduction of its contaminants content and its storage in bottles of an advanced design; • Use of a welding wire made to special specifications and stored in specialized vacuumed bags made of polyethylene film; • An analysis of possible methods of welding heat pipes and development of the best process for their welding that takes into account the physical, chemical and mechanical properties of the material and special operational aspects of structure. Key words: sealing of heat pipes, fixed joints between pipes, aluminum alloys, thin-walled small-diameter pipes

Computational design of transmembrane pores.

Protein pores play key roles in fundamental biological processes1 and biotechnological applications such as DNA nanopore sequencing2–4, and hence the design of pore-containing proteins is of considerable scientific and biotechnological interest. Synthetic amphiphilic peptides have been found to form ion channels5,6, and there have been recent advances in de novo membrane protein design7,8 and in redesigning naturally occurring channel-containing proteins9,10. However, the de novo design of stable, well-defined transmembrane protein pores capable of conducting ions selectively or large enough to allow passage of small-molecule fluorophores remains an outstanding challenge11,12. Here, we report the computational design of protein pores formed by two concentric rings of ɑ-helices that are stable and mono-disperse in both water-soluble and transmembrane forms. Crystal structures of the water-soluble forms of a 12 helical and a 16 helical pore are close to the computational design models. Patch-clamp electrophysiology experiments show that the transmembrane form of the 12-helix pore expressed in insect cells allows passage of ions across the membrane with high selectivity for potassium over sodium, which is blocked by specific chemical modification at the pore entrance. The transmembrane form of the 16-helix pore, but not the 12-helix pore, allows passage of biotinylated Alexa Fluor 488 when incorporated into liposomes using in vitro protein synthesis. A cryo-EM structure of the 16-helix transmembrane pore closely matches the design model. The ability to produce structurally and functionally well-defined transmembrane pores opens the door to the creation of designer pores for a wide variety of applications.

Effect of multi-groove reinforcement strategy on Cu/SiC surface composite fabricated by friction stir processing

In the present study, Cu/SiC surface composite was fabricated by friction stir processing (FSP) via multi-groove technique eyeing to improve SiC dispersion in copper matrix and hence improving mechanical and tribological behaviour. Microstructural features revealed more uniform dispersion of SiC particles in copper matrix when fabricated through multi-groove technique (MGT) as compared to single groove technique (SGT). The interface between copper matrix and SiC particles were clean without any obstruction/interruption in the form of voids or pores or intermediate phases formed which indicated excellent interfacial bonding. Furthermore, the obtained microstructure revealed drastic grain refinement in FSPed copper without reinforcement and the composites fabricated through SGT and MGT and the reduction in grain size was more for the composites fabricated by MGT. Tensile tests revealed incremental behaviour over strength with increase in number of grooves although it was far less as compared to base copper. Fractured surfaces of composites fabricated by both techniques (SGT and MGT) indicated reduction in ductility. However, results obtained for FSPed copper without reinforcement showed higher strength and ductility as compared to base copper. It was also demonstrated that incorporation of SiC particles in copper matrix improved hardness and wear resistance and it further enhanced with increased number of grooves. The wear mechanism changed with introduction of SiC particles in copper matrix and was supposed to be because of reduction in friction coefficient.

Pore development of the Lower Longmaxi shale in the southeastern Sichuan Basin and its adjacent areas: Insights from lithofacies identification and organic matter

X-ray diffraction (XRD), field emission/focusing ion beam scanning electron microscopy (FE-/FIB-SEM), nitrogen gas adsorption (N2GA), and geochemical analyses were performed on the Lower Longmaxi shale in the southeastern Sichuan Basin and its adjacent areas to reveal the controls of shale lithofacies and organic matter (OM) on pore development. The results showed that the Lower Longmaxi shale primarily comprises three types of lithofacies based on shale compositions and sedimentary environment: OM-rich siliceous shale (ORSS), OM-moderate mixed shale (OMMS) and OM-lean argillaceous shale (OLAS). ORSS comprises high contents of OM and siliceous minerals (quartz and feldspar), deposited in a deep-water shelf and early semi-deep-water shelf environment, while OLAS consists of high clay mineral and low OM contents, primarily formed in a shallow-water shelf environment. OMMS witness a transition from ORSS to OLAS in sedimentary environment and shale components. OM hosts a higher volume of pores per unit weight compared to inorganic minerals, corresponding to 0.1878 ml/g and 0.00396 ml/g, respectively. OM-hosted pores are dominant in ORSS, constituting 72%, whereas OLAS mainly consists of mineral-hosted pores, comprising 63.2%. OM-hosted and mineral-hosted pores in OMMS exist in similar proportions, namely, 56.4% and 43.6%, respectively. Differentiated diagenetic paths resulting from sedimentary environment are responsible for the differences in pore development under various shale lithofacies. The thermal maturity, macerals, and abundance of OM all play a significant role in the morphology and development of OM-hosted pores. OM-hosted pores are primarily founded in migrated OM (mainly sapropelic type), instead of structured OM (mainly humic type), in the form of secondary pores that are derived from dry gas-generation stage. Furthermore, OM-hosted pore development in shale gas reservoirs is slowed or even reduced because of the weakening of shale's resistance to compaction resulting from excessively high OM content.

Physical modification of concrete mix and concrete

Numerous studies have established that the physicomechanical properties of concrete, in addition to cement activity, type of aggregates, etc., are determined by the V/C value of the concrete mixture [1, 2, 3, 4, 5, 6, 7, 8, 9, 10]. The dependence of the strength and water tightness of concrete on H/C follows from the physical nature of the formation of the concrete structure. Studying the process of cement hydration showed that cement, depending on the quality and duration of hardening, binds only 15 … 25% of the water of its mass [11, 12, 13]. During the first month, at least 20% of the water by weight of the cement is bound. At the same time, to give the concrete mixture plasticity, improve the conditions of binder hydration, a significantly larger amount of water is introduced, since at W/C = 0.20 the concrete mixture remains practically dry and it cannot be qualitatively laid, molded and compacted. Excess water, without entering into chemical reactions with cement, remains in concrete in the form of water pores and capillaries or evaporates, leaving air pores. Undoubtedly this is the main reason for the decrease in the strength and waterproofness of concrete.

Variation of the Curie Temperature in Porous Materials

The dependence of the temperatures of magnetic phase transformations in porous ferromagnetic materials on the geometric characteristics (volume and shape) of pores and their distribution in a particular material has been studied. The geometric features of nanopores have been characterized by their effective pore radius and form factor (deviation of the pore shape from spherical). Estimations indicate that it is possible to obtain macroscopic samples of porous materials with decreased Curie temperatures, which can be further reduced in the case of complicated shapes of pores. These results were obtained in the framework of a cohesive model in application to pure porous nickel and cobalt.

An ordinary state-based peridynamic model for toughness enhancement of brittle materials through drilling stop-holes

In this paper, the ordinary state-based peridynamic (OSB) is used to simulate and study the effects of different-shaped stop-holes with different combinations on crack dynamics in brittle materials in order to establish a detailed knowledge about the toughening effect of internal features that can be in the form of holes and pores. Using the OSB analyses, a new easy-to-apply technique is presented to toughen the materials against crack propagations. As a first case study, the high accuracy of peridynamic approach in damage prediction is demonstrated through solving a collection of numerical and experimental benchmark problems. Moreover, the bi-hole, parabolic, branched, bi-parabolic, and mixed-parabolic combinations of stop-holes under tensile loading, and the T-shape, I-shape, bi-linear, linear, and linear-parabolic combinations of stop-holes under shear loading are suggested for notably enhancing material toughness and are practically and functionally compared with each other. Generally, the suggested geometries are proven to be highly effective on toughness enhancement of materials with a relative ease of implementation, in comparison to other internal features such as micro-cracks. In addition, a further case study is carried out on the effects of the distance of stop-holes from the initial crack-tip on crack dynamics and material toughness, in which it is observed that every hole has a specific µ-range, and thus, the crack dynamics are affected by the hole if and only if the crack enters this range. Overall, the arrestment and accelerating effects of the stop-holes on crack dynamics are carefully explained numerically and conceptually, which will help engineers and designers to maximize the positive effects of stop-holes on material toughness and design a tougher micro-structural material using easily applied defects.

Analysis of Microstructure and Properties of a Ti–AlN Composite Produced by Selective Laser Melting

Selective Laser Melting (SLM) is a manufacturing technique that is currently used for the production of functional parts that are difficult to form by the traditional methods such as casting or CNC (Computer Numerical Control) cutting from a wide range of metallic materials. In our study, a mixture of commercially pure titanium (Ti) and 15% at. aluminum nitride (AlN) was Selective Laser Melted to form three-dimensional objects. The obtained 4 mm edge cubes with an energy density that varied from 70 to 140 J/mm3 were examined in terms of their microstructure, chemical and phase composition, porosity, and Vickers microhardness. Scanning Electron Microscopy (SEM) observations of the etched samples showed inhomogeneities in the form of pores and unmelted and partly melted AlN particles in the fine-grained dendritic matrix, which is typical for titanium nitrides and titanium aluminum nitrides. The AlN particles remained unmelted in samples, but no porosity was observed in the interface area between them and the dendritic matrix. Additionally, samples fabricated with the presintering step had zones with different sizes of dendrites, suggesting a differing chemical composition of the matrix and the possibility of the formation of the phases forming an Ti–Al–N ternary system. The chemical composition in the microareas of the samples was determined using Energy Dispersive X-Ray Spectroscopy (EDS) and revealed differences in the homogeneity of the samples depending on the SLM process parameters and the additional presintering step. The phase composition, examined using X-ray Diffraction analysis (XRD), showed that samples were formed from Ti, TiN, and AlN phases. Porosity tests carried out using a computer microtomography revealed porosities in a range from 7% to 17.5%. The formed material was characterized by a relatively high hardness exceeding 700 HV0.2 over the entire cross-section, which depended on the manufacturing conditions.

Numerical computation of compliance contribution tensor of a concave pore embedded in a transversely isotropic matrix

The main objective of this work is to estimate the compliance contribution tensor of the concave pore inhomogeneity surrounded by a transversely isotropic matrix. In this light, we make use of a recently developed adapted boundary conditions based Finite Elements Method to incorporate the matrix anisotropy and the correction of the bias induced by the bounded character of the mesh domain, which allows to accelerate the computation convergence without sacrificing its accuracy. The correction of the boundary conditions is given as functions of the Green tensor and its gradient as dependent on the anisotropic elasticity of the matrix material, which are rigorously calculated by means of the Fourier transform based integral method in particular for regularizing the singularities on the symmetric axis of the transverse isotropy. Simultaneously by complying with the numerical homogenization technique, the compliance contribution tensor is computed for different forms of pores (e.g. superspheroidal and superspherical ones, etc) embedded in an transversely isotropic matrix. The proposed numerical method is shown to be efficient and accurate after several appropriate assessment and validation by comparing its predictions, in some particular cases, with analytical results and some available numerical ones. Finally, the effect of the pore concavity on the compliance contribution tensor is quantitatively illustrated.

Patterns of Fracture Initiation in Metallic Materials with a Heterogeneous Structure under Dynamic Cyclic Loading

The process of nucleation of fatigue defects in metal alloys with different structural morphology is considered. A physical model was built, calculation expressions were presented, a numerical experiment was performed to determine the moment of nucleation of the critical-size defect in Fe-based alloys during high-speed droplet impacts. The physical model is based on the theory of dislocations. It is shown that the determining factor in the process of wear nucleation under dynamic cyclic loading has a structural factor. Depending on the structure and properties of the material, as well as on the nature of the loads, the critical fatigue defect develops in the form of cracks, pores or microcraters. Comparative data of calculations and bench tests for droplet impingement erosion were presented. The contribution of the nucleation stage during the incubation period of erosive wear of the materials studied was evaluated. Due to the fact that rigorous instrumental methods for determining the duration of the nucleation stage are absent, the usage of the proposed analytical model is recommended for this purpose.

Pore Formation during Laser Welding in Different Spatial Positions

The process of formation of pores, cavities and similar defects in welded joints of stainless steels and aluminum alloys, affecting their quality, directly depends on spatial weld position in laser welding. Reducing the angle of inclination from 90° to 0° during downhill and uphill welding of AISI 321 stainless steel in the pulse mode of laser generation leads to an increase in both the number of pores and their size. At the same time, defects in the form of pores are not observed in the continuous mode of laser generation. In laser welding of butt joints of AISI 321 steel, the flat and vertical weld positions are the most promising, as they provide the highest level of quality. In order to provide a stable formation of a high-quality butt joint of aluminum AMg6M alloy and to prevent the failure of laser equipment, the welding process should be carried out in a vertical uphill weld position.

DETERMINATION OF PORE TYPES AND POROSITY TRENDS USING OF VELOCITY-DEVIATION LOG FOR THE CARBONATE MISHRIF RESERVOIR IN HALFAYA OIL FIELD, SOUTHEAST IRAQ

Halfaya field is located south of Iraq towards southeast Amara city in Missan. Mishrif Formation is a major reservoir in Halfaya Oilfield and is one of the principal carbonate reservoirs in central and southeastern Iraq. The aim of this study is to predict pore types using well logs data at missing core intervals. This study includes calculating the velocity deviation log for the Mishrif carbonate reservoir in two wells in Halfaya oil fields (HF-1 and HF-2) by converting porosity-log data into a synthetic velocity log by means of a time-average equation. A velocity-deviation log, which is calculated by integrating a sonic log with a neutron-porosity or density log, provides a means of obtaining downhole details in carbonates about the major pore forms. These data can be used to track the downhole distribution of diagenetic processes and their effects on secondary porosity trends. The differences are plotted as a velocity-deviation log between the actual sonic log and the synthetic sonic log. These velocity-deviation logs reflect the different physical rock markings of different types of pores: (1) Positive velocity deviations mark areas in which pore types form frames dominate; (2) zero deviations indicate periods in which the rock lacks a rigid frame and exhibits dissolution porosity or microporosity; and (3) Negative deviations mark areas in which sonic velocities are remarkably low due to cavernous borehole walls, fractures or possibly high free-gas content. &nbsp

Towards permanent hydrophilic PVDF membranes. Amphiphilic PVDF-b-PEG-b-PVDF triblock copolymer as membrane additive

Poly(vinylidene fluoride) (PVDF) ultrafiltration membranes were prepared by non-solvent-induced phase separation (NIPS) using a blend of a new amphiphilic PVDF-based triblock copolymer (PVDF-b-PEG-b-PVDF) and high molar mass PVDF. During the phase inversion step, the triblock copolymer acts both as a pore forming and surface modifying agent. Thanks to the presence of the short PVDF blocks in the triblock copolymer, the hydrophilic PEG segment is fixed in the PVDF matrix, thus reducing the gradual loss of hydrophilic additive by leaching of the triblock copolymer out of the membrane matrix. The PVDF-b-PEG-b-PVDF triblock copolymer additive improved the surface hydrophilicity and significantly increased the pure water flux and permeability of the PVDF membrane. The membrane composition was optimized in terms of additive concentration and compared to membranes prepared with an equivalent amount of commercial PEG of similar molar mass. Pure water filtration tests and contact angle measurements suggested that addition of small amounts of the triblock copolymer additive (2–5% w/w) has a strong impact on the performance and hydrophilic characteristic of the PVDF membranes. The control tests showed that less than 30% w/w of the additive is lost after 9 months, while most commercial PEG (59% w/w) leached out of the membrane matrix in only two months.

Low Temperature Calorimetry Coupled with Molecular Simulations for an In-Depth Characterization of the Guest-Dependent Compliant Behavior of MOFs.

In this study adsorption microcalorimetry is employed to monitor the adsorption of four probes (argon, oxygen, nitrogen, and carbon monoxide) on a highly flexible mesoporous metal–organic framework (DUT-49, DUT = Dresden University of Technology), precisely measuring the differential enthalpy of adsorption alongside high-resolution isotherms. This experimental approach combined with force field Monte Carlo simulations reveals distinct pore filling adsorption behaviors for the selected probes, with argon and oxygen showing abrupt adsorption in the open pore form of DUT-49, in contrast with the gradual filling for nitrogen and carbon monoxide. A complex structural transition behavior of DUT-49 observed upon nitrogen adsorption is elucidated through an isotherm deconvolution in order to quantify the fractions of the open pore, contracted pore, and intermediate pore forms that coexist at a given gas pressure. Finally, the heat flow measured during the guest-induced structural contraction of DUT-49 allowed an exploration of complex open-contracted pore transition energetics, leading to a first assessment of the energy required to induce this spectacular structural change.