Permeability Measurements Research Articles

Hydrogen isotope permeation through interfaces and permeability of tungsten layers

The estimation of the hydrogen isotope flux through a fusion reactor wall component is important for the material selection and in order to guarantee a safe and economical reactor operation. Since the permeation flux through a component cannot be measured directly, due to the large size of such a component, the deuterium permeability of various fusion materials were investigated in the last years. In order to investigate, if an interface, meaning a change of materials in a component, has an influence on the permeation flux, combined material systems in laboratory scale are studied. The combined materials systems are produced by applying a thin W or Cu layer on a polished bulk steel or CuCrZr substrates by magnetron sputter deposition. In a previous study (Houben et al., 2022), the combined material system of Cu coated steel was investigated. The conclusion was that the interface has a minor influence on the permeation flux compared to the large influence of the layer microstructure. In order to investigate, if the minor influence of the interface is valid in general, the systems W coated steel and CuCrZr are studied in this publication. By heating the substrate during W sputter deposition, a crack-free W layer is produced and crack propagation in the W layer at elevated temperature is prevented. The W layer permeabilities are obtained for both W coated substrates and are similar, but compared to the W bulk permeability from literature the W layer permeabilities are several orders of magnitude larger.The main conclusion from these studies is that in all investigated combined material systems the influence of the interface on the permeation flux is minor compared to the large influence of the microstructure. Therefore, for a reliable estimation of the permeation flux through a fusion reactor component it is crucial to characterize the applied materials. Especial for coatings the measurement of the layer permeability is important, since the layer permeability of a material can be very different compared to the permeability of a bulk material.

A siloxane interlayer approach to enhance surface metallization on polyamide fabrics via electroless copper deposition

Synthetic polymers, such as polyamide (PA), inherently possess a moderate number of surface functionalities compared to natural polymers, which negatively impacts the uniformity of metallic coatings obtained through wet-chemical methods like electroless plating. The paper presents the use of a siloxane interlayer formed from the condensation of the hydrolyzed 3-triethoxysilylpropyl succinic anhydride (TESPSA) precursor as a strategy to modify the surface properties of polyamide 6.6 (PA66) fabrics and improve the uniformity of the copper surface coating. The application of the siloxane intermediate coating demonstrates a significant improvement in electrical conductivity, up to 20 times higher than fabrics without the interlayer. The morphology of the coatings was investigated using scanning electron (SEM) and laser confocal scanning microscopy (LSM). In addition, dye adsorption, flexural rigidity, air permeability and contact angle measurements were conducted to monitor the change in the PA66 properties after the siloxane functionalization.

Preparation and Characterization of GX-50 and Vitamin C Co-encapsulated Microcapsules by a Water-in-Oil-in-Water (W1/O/W2) Double Emulsion-Complex Coacervation Method.

Co-encapsulated xanthoxylin (GX-50) and vitamin C (Vc) microcapsules (GX-50-Vc-M) were prepared by the combination of a water-in-oil-in-water (W1/O/W2) double emulsion with complex coacervation. The W1/O/W2 double emulsion was prepared by two-step emulsification, and it has a uniform particle size of 8.388 μm and high encapsulation efficiencies of GX-50 (85.95%) and Vc (67.35%) under optimized process conditions. Complex coacervation occurs at pHs 4.0-4.7, which has the highest encapsulation efficiency of GX-50 and Vc at pH 4.5. The complex coacervate with tannic acid solidifying (namely, wet microcapsules) has better mechanical properties and also enhances the ability of co-encapsulation of active ingredients. The resulting microcapsules by freeze-drying of wet microcapsules were characterized by UV-vis absorbance spectroscopy (UV-vis), Fourier infrared spectroscopy (FI-IR), confocal laser scanning microscopy (CLSM), scanning electron microscopy (SEM), X-ray diffraction (XRD), 2,2-diphenyl-1-picrylhydrazyl (DPPH·) radical scavenging, and in vitro permeation measurements. Under optimal conditions, the encapsulation efficiency and drug loading of GX-50-Vc-M for GX-50 and Vc are, respectively, 78.38 ± 0.51 and 59.34 ± 0.56%, and 35.6 ± 0.68 and 29.8 ± 0.92%. A slight shift in the FTIR peak between single GX-50 or Vc and GX-50-Vc-M confirmed the successful co-encapsulation of GX-50 and Vc in microcapsules. GX-50-Vc-M has bridged irregular spherical aggregates, while GX-50 and Vc are, respectively, encapsulated in hydrophobic and hydrophilic cavities of microcapsules in an amorphous dissolved state. GX-50-Vc-M has the highest DPPH· radical scavenging rate of 62.51%, and the scavenging process of GX-50-Vc-M on DPPH· radicals is more in line with the pseudo-second-order kinetic equation model. Moreover, the in vitro permeation of GX-50 and Vc in GX-50-Vc-M can reach maximum values of 40 and 60%, respectively. This concludes that GX-50-Vc-M is a promising delivery system for the penetration of the antioxidant into the deeper layers of the skin for the antioxidant effect.

Diffusion of Alloying Cobalt Oxide (II, III) into Electrical Steel.

This paper aims to reduce power loss in electrical steel by improving its surface resistivity. The proposed approach involves introducing additional alloying elements through diffusion once the steel sheet reaches the desired thickness. Various effective techniques have been suggested and tested to enhance the resistivity of the strip. The method entails creating a paste by combining powdered diffusing elements with specific solutions, which are then applied to the steel's surface. After firing the sample, a successful transfer of certain elements to the steel surface is achieved. The amount and distribution of these elements can be controlled by adjusting the paste composition, modifying the firing parameters, and employing subsequent annealing procedures. This study specifically investigates the effectiveness of incorporating cobalt oxide (II, III) into non-oriented silicon iron to mitigate power loss. The experimental samples consist of non-oriented electrical steels with a composition of 2.4 wt% Si-Fe and dimensions of 0.305 mm × 300 mm × 30 mm. Power loss and permeability measurements are conducted using a single strip tester (SST) within a magnetic field range of 0.5 T to 1.7 T. These measurements are performed using an AC magnetic properties measurement system under controlled sinusoidal conditions at various frequencies. The research explores the impact of cobalt oxide (II, III) addition, observing successful diffusion into the steel through the utilization of a paste based on sodium silicate solution. This treatment results in a significant reduction in power loss in the non-oriented material, with power loss reductions of 14% at 400 Hz and 23% at 1 kHz attributed to the elimination of a porous layer containing a high concentration of the diffusing element. The formation of porosity in the cobalt addition was found to be particularly sensitive to firing temperature near the melting point. The diffusion process was examined through scanning electron microscopy (SEM) in combination with energy-dispersive X-ray spectroscopy (EDS). The results demonstrate improved power losses in the coated samples compared with the uncoated ones. In conclusion, this study establishes that the properties of non-oriented electrical steels can be enhanced through a safer process compared with the methods employed by previous researchers.

Optimization of Mass and Light Transport in Nanoparticle-Based Titania Aerogels.

Aerogels composed of preformed titania nanocrystals exhibit a large surface area, open porosity, and high crystallinity, making these materials appealing for applications in gas-phase photocatalysis. Recent studies on nanoparticle-based titania aerogels have mainly focused on optimizing their composition to improve photocatalytic performance. Little attention has been paid to modification at the microstructural level to control fundamental properties such as gas permeability and light transmittance, although these features are of fundamental importance, especially for photocatalysts of macroscopic size. In this study, we systematically control the porosity and transparency of titania gels and aerogels by adjusting the particle loading and nonsolvent fraction during the gelation step. Mass transport and light transport were assessed by gas permeability and light attenuation measurements, and the results were related to the microstructure determined by gas sorption analysis and scanning electron microscopy. Mass transport through the aerogel network was found to proceed primarily via Knudsen diffusion leading to relatively low permeabilities in the range of 10-5-10-6 m2/s, despite very high porosities of 96-99%. While permeability was found to depend mainly on particle loading, the optical properties are predominantly affected by the amount of nonsolvent during gelation, allowing independent tuning of mass and light transport.

The low permeability of the Earth’s Precambrian crust

The large volume of deep groundwater in the Precambrian crust has only recently been understood to be relatively hydrogeologically isolated from the rest of the hydrologic cycle. The paucity of permeability measurements in Precambrian crust below 1.3 km is a barrier to modeling fluid flow and solute transport in these low porosity and permeability deep environments. Whether permeability-depth relationships derived from measurements shallower than 1.3 km can be extended to greater depths in unclear. Similarly, application of a widely-used permeability-depth relationship from prograde metamorphic and geothermal systems to deep Precambrian rocks may not be appropriate. Here, we constrain permeabilities for Precambrian crust to depths of 3.3 km based on fluid residence times estimated from noble gas analyses. Our analysis shows no statistically significant relationship between permeability and depth where only samples below 1 km are considered, challenging previous assumptions of exponential decay. Additionally, we show that estimated permeabilities at depths >1 km are at least an order of magnitude lower than some previous estimates and possibly much lower. As a consequence, water and solute fluxes at these depths will be extremely limited, imposing important controls on elemental cycling, distribution of subsurface microbial life and connections with the near-surface water cycle.

Effect of hydrogen on impact fracture of X80 steel weld: Various heat inputs and coarse grain heat-affected zone

In this work, the impact fracture of coarse grain heat-affected zone (CGHAZ) of an X80 steel weld with various heat inputs was investigated in the absence and presence of hydrogen (H)-charging by metallographic characterization, microhardness and impact testing, electrochemical H permeation measurements. The results show that, as the heat input (HI) during welding decreases, the microstructure of the CGHAZ changes from granular bainite (GB) to lath bainite (LB). When the LB content exceeds 70%, the microhardness of the material increases remarkably. For H-free specimens, the fracture surface transforms from ductile to brittle fracture at the HI of 29.2 kJ/cm. Upon H-charging, the fracture surfaces show brittle transgranular cleavage fracture when the HI is 18.1 kJ/cm. The H atoms decrease the threshold HI where a brittle fracture occurs. Compared with the GB microphase, the LB-containing microstructure requires a higher H concentration to cause transgranular impact brittle fracture.

Depression, Inflammation, and Intestinal Permeability: Associations with Subjective and Objective Cognitive Functioning throughout Breast Cancer Survivorship.

About one-in-three breast cancer survivors have lingering cognitive complaints and objective cognitive impairment. Chronic inflammation and intestinal permeability (i.e., leaky gut), two risk factors for cognitive decline, can also fuel depression-another vulnerability for cognitive decline. The current study tested whether depression accompanied by high levels of inflammation or intestinal permeability predicted lower subjective and objective cognitive function in breast cancer survivors. We combined data from four breast cancer survivor studies (n = 613); some had repeated measurements for a total of 1015 study visits. All participants had a blood draw to obtain baseline measures of lipopolysaccharide binding protein-a measure of intestinal permeability, as well as three inflammatory markers that were incorporated into an inflammatory index: C-reactive protein, interleukin-6, and tumor necrosis factor-α. They reported depressive symptoms on the Center for Epidemiological Studies depression scale (CES-D), and a binary variable indicated clinically significant depressive symptoms (CES-D ≥ 16). The Kohli (749 observations) and the Breast Cancer Prevention Trial (591 observations) scales assessed subjective cognitive function. Objective cognitive function tests included the trail-making test, Hopkins verbal learning test, Conners continuous performance test, n-back test, FAS test, and animal-naming test (239-246 observations). Adjusting for education, age, BMI, cancer treatment type, time since treatment, study visit, and fatigue, women who had clinically elevated depressive symptoms accompanied by heightened inflammation or intestinal permeability reported poorer focus and marginally poorer memory. However, poorer performance across objective cognitive measures was not specific to inflammation-associated depression. Rather, there was some evidence of lower verbal fluency; poorer attention, verbal learning and memory, and working memory; and difficulties with visuospatial search among depressed survivors, regardless of inflammation. By themselves, inflammation and intestinal permeability less consistently predicted subjective or objective cognitive function. Breast cancer survivors with clinically significant depressive symptoms accompanied by either elevated inflammation or intestinal permeability may perceive greater cognitive difficulty, even though depression-related objective cognitive deficits may not be specific to inflammation- or leaky-gut-associated depression.

The Harpers THMC flow bench: A triaxial multi-reactor setup for the investigation of long-term coupled thermo-hydro-mechanical-chemical fluid-rock interaction.

The scientific analysis and interpretation of coupled thermo-hydro-mechanical-chemical (THMC) processes in rocks requires complex and diverse instrumentation. In this study, we introduce the "Harpers THMC Flow Bench," a multi-cell, flow-through reactor system that allows long-term testing on rock plugs and powdered samples. The setup consists of four small triaxial cells that can hold confining and pore pressure of up to 20 MPa and an axial load of up to 300 MPa. Axial deformation of the samples is measured with linear variable differential transducers. The cells can be heated to 90 °C, and effluents (gas, water, and brine) can be sampled for compositional analysis. An additional Hastelloy-autoclave enables fluid mixing and saturation with gas prior to injection into the samples. Each cell can be operated individually, allowing independent experiments over long testing periods. The sample holders were designed such that they are transparent for X-rays during X-ray computer tomography, minimizing sample handling effects on the imaging results. To demonstrate examples of the capabilities of the flow bench, we present case studies on Carnmenellis granite (Cornwall, UK) and Castlegate sandstone (Utah, USA) samples. Permeability measurements are shown using fractured granite undergoing periodic loading of effective pressure. To demonstrate chemical measurement capabilities, we used deionized water to leach elements from granite powders. We then analyzed effluent compositions using inductively coupled plasma optical emission spectroscopy. Finally, we conducted a strength test and a cyclic differential stress test on sandstone to demonstrate the mechanical testing capabilities of the setup.

Accurate measurement of gas permeation through sub-nanopores of two-dimensional materials by mass spectrometry

Accurate measurement of gas permeation through sub-nanopores of two-dimensional materials by mass spectrometry

A Convenient Device to Measure the Permeability of Intact Rock (Heterogeneity and Anisotropy)

Abstract The permeability of intact rocks affects a wide range of natural and engineered systems, yet its measurement remains costly and involves time demanding test protocols. Gas permeameters may improve efficiency but involve a complex series of pore-scale processes. In addition, peripheral damage during coring and the jacket-rock interface create a preferential flow path that affects the inferred permeability. We present a convenient permeameter for liquid-based permeability measurements using an unjacketed disk specimen. The test configuration minimizes peripheral flow bias and expedites testing times. The permeameter uses readily available devices for pressure and flow rate measurement/control and can be readily configured to measure rock permeability across six orders of magnitude. Preliminary numerical simulations allowed us to optimize the test design, to extract coefficients for data correction, and to process data to recover permeability anisotropy. The system is experimentally verified against industry standards and used to test cleaning protocols to remove fines left on the specimen surface after specimen preparation; these fines may cause clogging at the inlet phase—a bias that affects all permeameters.

Clog-Resistant Permeable Pavement: Methods of Performance Measurement

Permeable pavements are considered to be one of the effective measures for LID (i.e. Low Impact Development) and SUDS (i.e. Sustainable Urban Drainage System) globally. The major three types of permeable pavements are (a) pervious concrete (PC), (b) previous asphalt (PA), and (c) permeable interlocked concrete paver (PICP). The performance of all types of permeable is satisfactory at the start of the service life but greatly reduced if not maintained on time. Considering the long lengths of the pavements, measurement of permeability at different locations is a cumbersome and tedious task. Therefore, ease of performance and realistic results are of vital importance. In this study, ASTM C1701/C1701M—17a single ring infiltrometer, Stormwater Infiltration Field Test (SWIFT), and NCAT permeameter Methods are discussed in detail and examined for their relative ease of setting-up, versatility and performance. It is concluded that ASTM C1701/C1701M—17a single ring infiltrometer is the most versatile, easy to set up and produces accurate results.

Nanocomposites Based on Pyrolyzed Polyacrylonitrile Doped with FeCoCr/C Transition Metal Alloy Nanoparticles: Synthesis, Structure, and Electromagnetic Properties.

In the last decade, the development of new materials that absorb electromagnetic radiation (EMR) has received research interest as they can significantly enhance the performance of electronic devices and prevent adverse effects caused by electromagnetic pollution. Electromagnetic radiation absorbers with a low weight and small thickness of the absorber layer, good absorption capacity, and a wide frequency response bandwidth are highly demanded. Here, for the first time, the properties of polymer nanocomposites FeCoCr/C synthesized by doping FeCoCr alloy nanoparticles into a polymer matrix of pyrolyzed polyacrylonitrile are investigated. An analysis of the magnetic properties of FeCoCr/C nanocomposites showed that increasing the synthesis temperature increased the specific magnetization and coercive force values of the FeCoCr/C nanocomposites. The dependence between the ratio of metals in the precursor of pyrolyzed polyacrylonitrile and the electromagnetic and wave-absorbing properties of FeCoCr/C nanocomposites is considered, and the results of complex dielectric and magnetic permeability measurements are analyzed. It is found that the most promising of all the studied materials are those obtained at T = 700 °C with the ratio of metals Fe:Co:Cr = 35:35:30.

Evaluating the accuracy of liquid permeability measurements in shale and tight rocks using transient flow method and comparison with gas permeability

The transient flow method for measuring permeability to liquid is a useful technique for shale and tight rocks; however, it is not as popular as the steady-state method in these rocks. One of the issues is the lack of clarity on a key term of compressibility of the fluid and rock system. Various forms of compressibility have been used in literature, which can lead to inconsistent results of liquid permeability. Using gas for the permeability measurement is more common in shale, and the Klinkenberg corrected permeability is often used to represent liquid permeability; however, how the Klinkenberg permeability is compared to liquid permeability in shale or tight rocks is not adequately addressed. This paper presents a study using the transient flow method for water and oil permeability measurement in three Eagle Ford Shale samples. Gas permeability was also measured for these samples. Different forms of the total compressibility of the fluid-rock system (Ct) are summarized from literature, and a new form of Ct is proposed. The accuracy of the calculations based on different forms of Ct is evaluated through the comparison between water and oil permeabilities and the comparison with gas permeability. The results are also compared with oil permeability obtained from the steady-state method. The new form of Ct provided the most accurate results, whereas the other forms of Ct led to errors. However, for samples with bulk compressibility of less than 1 × 10−7 psi−1, the error using those forms of Ct was negligible. The study also found that the Klinkenberg permeability obtained from the linear extrapolation is larger than the oil permeability for two samples by 12% and 37%, respectively, whereas it is smaller than the oil permeability for the other sample. This comparison suggests that a nonlinear gas slippage effect may exist in the high pressure range (>2000 psi) for shale or tight rock samples.

Microwave permittivity and permeability measurements on lunar simulants at low temperatures

Lunar simulants are used to approximate the behavior of the lunar regolith. This work focuses on materials responses relevant for microwave heating to inform in-situ resource utilization of lunar regolith for landing pads and building infrastructure. Microwave dielectric permittivity and magnetic permeability measurements have been made for the first time on several new highland lunar simulants (NU-LHT-4M, NUW-LHT-5M and CSM-LHT-1G). One mare lunar simulant (JSC-1A) is included in this work. We present these measurements in the low temperature range −185 °C to 250 °C and in the frequency range 50 MHz to 3 GHz. The dominant minerals in the simulants are the minerals bytownite, ortho- and clino-pyroxenes, olivine, and glass. Less complex rock feedstocks for highland simulants, anorthosite and pyroxenite, were also measured separately. The dielectric measurements were performed on samples having different densities. Differences in the dielectric responses were noted, however all simulants were weak microwave absorbers at the low temperatures. This data assists with planning for a hybrid approach to microwave sintering at the lunar south pole.

Continuous measurement of gas permeability in non-homogeneous hydrate reservoirs under effective pressure via a novel apparatus

Gas permeability is a key physical parameter to determine the exploitation efficiency of natural gas hydrate (NGH). However, the relevant research mainly focuses on the permeability of homogeneous hydrate reservoirs, there have been no studies of non-homogeneous hydrate reservoirs. Therefore, a novel permeability measurement apparatus was designed in this study, which used two core holders in parallel to achieve the spatio-temporal continuous measurements of gas permeability for non-homogeneous reservoirs. Marine soils obtained from the South China Sea were used to remold the non-homogeneous hydrate reservoirs, including two homogeneous hydrate reservoirs with water saturation of 40% (reservoir A) and 80% (reservoir B), respectively. The constant gas flow of 0.5 ml/s and constant back pressure of 3 MPa was carried out to measure the gas permeability. The experimental results showed that the gas permeability measured in this work had similar regularities with other literature data. When the effective pressure increased from 1 MPa to 6 MPa, the permeability of reservoir A, reservoir B, and non-homogeneous hydrate reservoir decreased from 15.2 mD to 10.9 mD, 10.5 mD to 4.6 mD, and 12.5 mD to 8.5 mD, respectively. In addition, the variation in the non-homogeneous coefficient showed three stages: 1–2 MPa stage, 2–3 MPa stage, and 3–6 MPa stage. What's more, the permeability damage rate of non-homogeneous reservoirs increased by nearly 35% with the increase of effective pressure. These findings obtained by this apparatus will enhance the understanding of gas permeability in the non-homogeneous hydrate reservoirs, and guide further field exploitation of hydrate reservoirs.

Influence of Frictional Heat on Hydrogen Permeation Measurements

Hydrogen transport properties in metals are often investigated in electrochemical Devanathan-Stachurski double cells (DS) or modifications thereof. A DS setup consists of input and output cells which are divided by a metal membrane. The hydrogen oxidation current measured in the output cell is proportional to the permeation rate of hydrogen through the metal membrane. In certain applications of lubricated tribocontacts, steel is susceptible to damages by uptake of hydrogen. For investigation of the friction-generated hydrogen uptake a lubricated sliding contact in the input cell of the DS setup is realized.Related low hydrogen permeation current signals are significantly affected by the steel membrane temperature. As an example, frictional heating of the steel membrane leads to additional release of residual hydrogen from the steel. To investigate the temperature effect, tests with an oil containing a hydrogen promotor, a PFPE oil and without lubrication were conducted. The results indicate that the permeation signal is strongly influenced by frictional heating. Such measured currents must not be misinterpreted as hydrogen generated by lubricants. A thermodynamic and kinetic model of the hydrogen diffusion and trapping reveals the correlation between current signal and temperature change.

Degradation Evaluation of LaCrO3-Based Interconnect on the Basis of Oxygen Permeation Measurements

Degradation of LaCrO3-based Interconnect was evaluated by comparing the oxygen permeation flux for flat tube SOFC cell before and after long term operation (20,000 hours). Oxygen permeation flux was estimated based on the amount of water vapor, which was generated as a result of oxygen permeation from the hydrogen side to the air side. The estimated oxygen permeation flux for the SOFC cell before long term operation was found to be in the range of 0.02~0.06 mL cm−2 min−1 at 750 °C. For the cell after long term operation, the oxygen permeation flux was determined to be 0.049 mL cm−2 min−1, which was almost similar with that for the cell before long term operation. This suggested that degradation of LaCrO3-based Interconnect, i.e., increase in oxygen permeation, is quite small.

Effective permeability changes during hydrate production

The effective permeability impacted hydrate production severely. But its changes during hydrate production are studied few, due to no stable pressure and temperature for permeability measurement. Herein, this condition was achieved by the intermittent depressurization. The effective permeability of hydrate-bearing samples was measured. The feasibility of this method was analyzed by hydrate dissociation and saturation. Afterwards, the measured and predicted effective permeability were compared and further analyzed from hydrate distribution, preferential flow path, and fresh hydrates. The results showed that hydrate dissociation of 1.24%–2.22% did not impact measurements. Hydrate distribution, preferential flow path, and fresh hydrates were found to have a larger effect on the random changes of the effective permeability during hydrate production in comparison of hydrate saturation and pore habits. The stronger heterogeneity of hydrate distribution caused the greater randomness that the effective permeability difference was 0.346 D-0.4 D at the close hydrate saturations. Under this situation, the fixed preferential flow path was possible to form and stabilized effective permeability at 0.563 D-0.569 D. In the sample with a weaker heterogeneous hydrate distribution, the more apparent randomness was increased by fresh hydrate saturation of 1.66%–5.08%. This work may be beneficial to understand gas-water flow capacity in real settings.

Internal oxidation of austenitic Fe-Ni-Cr alloys at high temperatures: Deduction of oxygen permeability and the influence of carbon-bearing gases

Internal oxidation was employed to determine oxygen permeability in the Fe-Ni system between 1000 ºC and 1150 ºC at the oxygen partial pressures of Fe/FeO equilibrium. Fe-Ni-Cr alloys were exposed to environments with and without carbon to assess the influence of dissolved carbon on oxygen permeability. A detailed examination of the classical diffusion model for internal oxidation allowed increased accuracy of the permeability measurement. Oxygen permeability decreased nonlinearly with Ni content in the alloy, driven by a decrease in oxygen solubility. No carbon effect was detected in Ni-containing alloys.