Increase In Impedance Research Articles

The effect of phonons-surface and grain-boundary scattering on electrical properties of metallic Ag

Explain in this study, thickness has an inverse relationship with electrical resistivity and a linear relationship with Grain boundary scattering. According to the (Fuchs-Sondheier, Mayadas-Shatzkces) model, grain boundary scattering leads To an Increase in electrical Resistivity. The surface scattering Coefficient of Ag, which Fuchs-Sondheier and Mayadas-Shatzkces measured at , Ag's grain boundary reflection coefficient , which Mayadas-Shatzkces measured at , If the concentration of material has an effect on metal's electrical properties, According to this silver is a good electrical conductor and is used frequently in electrical and electronic circuits.

Enhancing the Longevity and Functionality of Ti-Ag Dry Electrodes for Remote Biomedical Applications: A Comprehensive Study.

This study aims to evaluate the lifespan of Ti-Ag dry electrodes prepared using flexible polytetrafluoroethylene (PTFE) substrates. Following previous studies, the electrodes were designed to be integrated into wearables for remote electromyography (EMG) monitoring and electrical stimulation (FES) therapy. Four types of Ti-Ag electrodes were prepared by DC magnetron sputtering, using a pure-Ti target doped with a growing number of Ag pellets. After extensive characterization of their chemical composition and (micro)structural evolution, the Ti-Ag electrodes were immersed in an artificial sweat solution (standard ISO-3160-2) at 37 °C with constant stirring. Results revealed that all the Ti-Ag electrodes maintained their integrity and functionality for 24 h. Although there was a notable increase in electrical resistivity beyond this timeframe, the acquisition and transmission of (bio)signals remained viable for electrodes with Ag/Ti ratios below 0.23. However, electrodes with higher Ag content (Ag/Ti = 0.31) became insulators after 7 days of immersion due to excessive Ag release into the sweat solution. This study concludes that higher Ag/Ti atomic ratios result in heightened corrosion processes on the electrode's surface, consequently diminishing their lifespan despite the advantages of incorporating Ag into their composition. This research highlights the critical importance of evaluating electrode longevity, especially in remote biomedical applications like smart wearables, where electrode performance over time is crucial for reliable and sustained monitoring and stimulation.

Mechanism of oxygen vacancies migration in BaTiO3‐BiMeO3: Experimental investigations and first principles studies

AbstractBaTiO3‐based compounds are recognized as the most common dielectric material used in multilayer ceramic capacitors (MLCCs), among which, BaTiO3‐BiMeO3 is extensively investigated to improve the thermal stability and extend the service life of MLCCs, which are strongly dependent on the conductivity at high temperatures. Despite numerous efforts have been made, the mechanism of oxygen vacancy conduction, which makes the major contributions to the conduction mechanism of BaTiO3‐based compounds at high temperatures below 450°C, is still unclear. In this paper, BaTiO3, 0.88BaTiO3‐0.12Bi(Zn2/3Nb1/3)O3, 0.88BaTiO3‐0.12Bi(Mg2/3Nb1/3)O3, and 0.88BaTiO3‐0.12Bi(Mg2/3Ta1/3)O3 ceramics have been prepared by solid‐state reaction method, and their electrical and dielectric properties have been studied in detail. Meanwhile, first principles were applied to study the mechanisms of the increase of electrical resistivity and the decrease of dielectric loss. It is found that B‐site dopants (Zn, Mg, Nb, and Ta) are effective in reducing the conductivity by inhibiting the migration of oxygen vacancies, which is a kinetics process with an increase of energy barrier. Notably, the greater ability of Zn to inhibit oxygen vacancies migration is a combination of thermodynamics (a strong ability to trap oxygen vacancies) and kinetics (an effect of block the migrating defects in the lattice). This work reveals a new insight into the mechanism of oxygen vacancies migration in BaTiO3‐based perovskite compounds, which makes BaTiO3‐BiMeO3 prospective in designing efficient and durable medium‐temperature solid oxide capacitor devices.

Cannabidiol attenuates inflammatory impairment of intestinal cells expanding biomaterial-based therapeutic approaches

Cannabis-based biomaterials have the potential to deliver anti-inflammatory therapeutics specifically to desired cells, tissues, and organs, enhancing drug delivery and the effectiveness of anti-inflammatory treatment while minimizing toxicity. As a major component of Cannabis, Cannabidiol (CBD) has gained major attention in recent years because of its potential therapeutic properties, e.g., for restoring a disturbed barrier resulting from inflammatory conditions. The aim of this study was to test the hypothesis that CBD has beneficial effects under normal and inflammatory conditions in the established non-transformed intestinal epithelial cell model IPEC-J2. CBD induced a significant increase in transepithelial electrical resistance (TER) values and a decrease in the paracellular permeability of [³H]-D-Mannitol, indicating a strengthening effect on the barrier. Under inflammatory conditions induced by tumor necrosis factor alpha (TNFα), CBD stabilized the TER and mitigated the increase in paracellular permeability. Additionally, CBD prevented the barrier-disrupting effects of TNFα on the distribution and localization of sealing TJ proteins. CBD also affected the expression of TNF receptors. These findings demonstrate the potential of CBD as a component of Cannabis-based biomaterials used in the development of novel therapeutic approaches against inflammatory pathogenesis.

Magnetocaloric and hydrogen storage multi-functional properties of Eu4Ga8Ge16 compounds

We investigated the anisotropic magnetic, electrical transport, and heat capacity of Eu4Ga8Ge16 single crystals. Magnetization measurements with temperature and magnetic field revealed a complex behavior. Specifically, we observed anisotropic metamagnetic transitions at low magnetic field, and inverse hysteresis at high magnetic fields. These phenomena can be attributed to a Heisenberg ferromagnetic spin chain aligned along the a-axis. Additionally, this ferromagnetic behavior is interspersed with antiferromagnetic interactions between adjacent Heisenberg spin chains. We also noticed an anomalous increase in electrical resistivity at low temperature under magnetic fields, as well as different temperature-exponents of ρ(T) depending on crystal directions, which are attributed to the anisotropic scattering of carriers due to anisotropic magnetic interactions. We also evaluated the magnetocaloric effect and found a substantial magnetic entropy change than those of type-I Eu-based clathrates. The high entropy change (-ΔSM = 13.5 J kg−1 K−1) and adiabatic temperature difference (ΔTad = 7.8 K) near Néel temperature TN = 7.9 K reveal that the Heisenberg spin chain system might be advantageous for inducing a larger magnetic entropy change. Furthermore, we measured the hydrogen storage capacity of Eu4Ga8Ge16 as a multifunctional property because the zeolite-like cage structure can be a good candidate for hydrogen storage applications. Although the hydrogen storage capacity is considerably lower than that of the leading-edge materials, the hydrogen storage capacity can be improved further when we control the Eu-deficiency to place the hydrogen molecule at the cage site, because the hydrogen molecules reside at the (Ga,Ge) framework not in the cage site for fully occupied Eu atomic chain compounds. Hence, Eu4Ga8Ge16 emerges as a versatile substrate for engineering multifunctional energy materials, excelling in both low-temperature magnetocaloric effects and hydrogen storage potential.

Modified Membranes for Redox Flow Batteries-A Review.

In this review, the state of the art of modified membranes developed and applied for the improved performance of redox flow batteries (RFBs) is presented and critically discussed. The review begins with an introduction to the energy-storing chemical principles and the potential of using RFBs in the energy transition in industrial and transport-related sectors. Commonly used membrane modification techniques are briefly presented and compared next. The recent progress in applying modified membranes in different RFB chemistries is then critically discussed. The relationship between a given membrane modification strategy, corresponding ex situ properties and their impact on battery performance are outlined. It has been demonstrated that further dedicated studies are necessary in order to develop an optimal modification technique, since a modification generally reduces the crossover of redox-active species but, at the same time, leads to an increase in membrane electrical resistance. The feasibility of using alternative advanced modification methods, similar to those employed in water purification applications, needs yet to be evaluated. Additionally, the long-term stability and durability of the modified membranes during cycling in RFBs still must be investigated. The remaining challenges and potential solutions, as well as promising future perspectives, are finally highlighted.

Analysis of the Long-Term Operation of an Electrolyte-supported Solid Oxide Cell Under Co-electrolysis Regime

Solid oxide technology allows to produce synthesis gas (CO+H2), a relevant mixture and precursor for e-fuels and other products in the chemical industry. This work reports on the long-term performance of an electrolyte supported cell (Ni-CGO/3YSZ/LSCF-CGO), operating at industrially relevant co-electrolysis conditions (32.5 % H2/35 H2O/8.1 CO/24.4 CO2, -0.5 A/cm2, 816 °C). The applied cell had a Ni-CGO fuel electrode (~30 μm thick), a 3YSZ electrolyte (~90 μm) and an LSCF-CGO oxygen electrode (~35 μm thick) including a thin CGO protective layer.The cell was operated successfully for 2300 h at constant galvanostatic test conditions, with an overall degradation of 80 mΩ cm2/kh, which is a higher degradation rate than the reported for similar cells at comparable conditions. At the start of the test, the ohmic resistance contributes to almost 90 % of the ASR (area-specific resistance), but the increase in Rp (polarization resistance) is what contributes the most to the increase in ASR during the long-term operation.This increase in ASR is not constant over the entire test time. On the contrary, it is considerably higher during the first 300 hours (180 mΩcm2/kh) and then it falls and stabilizes during the last app. 2 kh of the long-term operation of the cell to 32 mΩcm2/kh. The increase in ohmic resistance is in percentage small but steady at 7 %/kh, while the increase in polarization resistance follows the same trend as the ASR.Electrochemical impedance spectroscopy (EIS) showed a decrease of the performance of the Ni-CGO fuel electrode. A possible explanation for the observed fuel electrode degradation was found via SEM-EDS, where a considerable quantity of silicon-containing species was found in the active area of the Ni-CGO fuel electrode.

Life Testing and Redox Cycling of Ni- and Ru-Doped Strontium Iron Titanate Exsolution Fuel Electrodes in Electrolyte-Supported Solid Oxide Cells

Recently perovskite materials have gained much attention as potential candidates for solid oxide cell (SOC) fuel electrodes due to their advantages of redox stability, coking resistance and sulfur resistance over their cermet counterparts. Enhanced electrochemical performance has also been observed for some of these perovskite materials resulting from exsolution, where nano-sized metal particles are formed on the material surface under reducing conditions. However, the degradation mechanism of these perovskite fuel electrodes has yet to be fully understood and the relationship between their long-term stability and operating envrionments (fuel-cell/electrolysis, fuel compositions, redox cycles, operating pressure, etc.) has not been fully investigated.Here, life tests were conducted in open-circuit and reversible operation at 850oC on electrolyte-supported symmetric and full cells with Ni and Ru-doped strontium iron titanate (Sr0.95Ti0.3Fe0.63Ni0.07O3 and Sr0.95Ti0.03Fe0.63Ru0.07O3) as fuel electrodes (SrTi0.3Fe0.6Co0.1O3 used as the air electrode in the full cells). For both materials, higher degradation rate was observed when operated with 97% H2 + 3% H2O compared with 50% H2 + 50% H2O as fuel; an increase in ohmic resistance and gas adsorption/desorption resistance contributed to most of the degradation observed. STFN also showed higher degradation rates than STFRu in both fuel compositions. Exsolution from both compositions was confirmed by scanning electron microscopy (SEM) and scanning transmission electron microscopy (STEM) with both fuel compositions and in situ X-ray Diffraction (XRD) showed the simultaneous perovskite to Ruddlesden-Popper (RP) phase transformation. The faster perovskite-RP phase transformation is believed to be responsible for the higher degradation rates observed for cells using fuel electrode materials with less stable perovskite structure (STFN over STFRu) and tested in more reducing fuel compositions (97% H2 over 50% H2). Moreover, redox cycles were introduced for STFN and STFRu during life tests and partial performance recovery was observed; in situ XRD and SEM microstructural analysis suggests that the recovery resulted from a transformation from RP back to perovskite for both materials. Finally full cell reversible operation durability tests (6 hrs each in fuel cell and electrolysis modes at 0.8 A/cm2) conducted at 850oC with 50% H2 + 50% H2O as fuel at 1 atm showed reasonably good stability over 1000 h. Initial reversible life testing at 3 atm operating pressure showed higher degradation rates, and the possible reasons for this will be discussed.

Durability and Interfacial Elemental Diffusion about BZYb based Protonic Ceramic Fuel Cell

Protonic ceramic fuel cells (PCFCs) are expected to be a highly efficient next-generation fuel cell because the fuel is not diluted by the generated water vapor during power generation. In the past research, we have found that Yb-doped BaZrO3 (BZYb) is promising in terms of the durability against CO2, proton conductivity, and less reactivity with NiO used for the fuel electrode. We are currently developing improvement of power generation efficiency and durability of PCFCs using BZYb electrolyte. In terms of the durability of PCFCs, there is concern about degradation due to diffusion of transition metals such as Co and Ni used in the air and fuel electrodes. In this study, we evaluated the durability of PCFCs using BZYb electrolyte focusing on the diffusion of transition metals derived from electrodes. We also examined the effect of a buffer layer on the air electrode side. In this study, fuel electrode supported cells with BaZr0.8Yb0.2O3-δ(BZYb20) electrolyte and NiO-BZYb20 fuel electrode was used. The fuel electrode half cells were fabricated by integrally firing process of the laminated green sheets of the electrolyte and fuel electrode to densify the electrolyte. For air electrode, BaZr0.375Yb0.125Co0.50O3-δ was screen printed on the fuel electrode half cell and fired at 900°C. For the cell with buffer layer between the air electrode and the electrolyte, BaCe0.7Zr0.1Y0.1Yb0.1O3- δ was spin-coated on the half-cell and then fired at 1300°C. The air electrode was then prepared in the same way. Durability tests were conducted at constant-current mode at 600°C, and the elemental diffusion state of the cells before/after the test was observed by cross-sectional EPMA. During 1000h power generation, the increase of ohmic resistance and polarization resistance was observed, and the increase in resistance was found to be smaller in cells with buffer layer. The results of cross-sectional EPMA analysis after the power generation test showed differences in the segregation state of Co and Ni in the electrolyte, with a tendency for segregation to be suppressed in the presence of a buffer layer.Acknowledgement: This work is partially based on results obtained from a project (JPNP20003), commissioned by the New Energy and Industrial Technology Development Organization (NEDO) of Japan.

Degradation Behavior of MK35x Stacks with Chromium-Based Interconnects in Steam Electrolysis Operation

The currently ongoing commercialization of high-temperature solid oxide electrolysis (SOEL) requires the understanding of the underlying dominant degradation mechanisms to enable continuous progress in reducing stack degradation rates.In the present study, the degradation behavior of stacks with chromium-based interconnects (MK35x) and electrolyte-supported cells (ESC) developed at Fraunhofer IKTS is investigated. For this purpose, the initial electrochemical performance of 10-layer stacks was extensively characterized in various operating conditions in both fuel cell and electrolysis mode by electrochemical impedance spectroscopy (EIS). Degradation was evaluated during galvanostatic steady-state steam electrolysis operation over >3000 h in the temperature range of 800-825°C at a current density of -0.6 A cm-2, corresponding to a steam conversion rate of 75%. EIS analysis was used to separate the different loss contributions in the stack and showed that the ohmic resistance increase was the dominating performance degradation phenomenon. Moreover, electrochemical degradation rates in steady-state SOEL mode are compared to the ones in reversible mode with a daily cycling between electrolysis and fuel cell operation.Post-mortem analysis was carried out with scanning electron microscopy (SEM) to correlate the observed degradation phenomena with microstructural and morphological changes. The observed low degradation rates demonstrate that MK35x are ready for scale-up, and the present work gives guidance for operation strategies and stack design to extend their lifetime even further.

Investigating the Influence on the Electro-Conductive Properties of Leather as a Result of Natural Aging

Conductive leather and its use in smart products have found a lot of interest. Leather behaves as a good insulator, so it was treated with electrically conducting polypyrrole using a chemical polymerization technique to give it conductive characteristics. The electro-conductive properties are obtained by using the double in–situ oxidative polymerization of pyrrole. The electrical properties of conductive samples are studied using the Van Der Pauw method as a measuring method. The conductive leather transformation process was carried out during the 2018-2020 period, and the conductive leather samples were preserved in room conditions until the year 2023. The effect of natural ageing on the electro-conductive properties of conductive leather is the focus of this research. The results show that environmental factors influence polymer breakdown and stability, by causing an increase in electrical resistance. The changes in electrical surface resistance, as the effect of the ageing factor, vary from 39.8% to 129.9%. Those changes in electrical resistance indicate that ageing is one of the major concerns in the electrical properties and stability of conductive leather samples, so the performed measurements have importance in providing information for the researchers and designers regarding the conductivity changes over time as a result of natural ageing, which would like to work with conductive leather on smart products.

Investigating the Influence on the Electro-Conductive Properties of Leather as a Result of Natural Aging

Conductive leather and its use in smart products have found a lot of interest. Leather behaves as a good insulator, so it was treated with electrically conducting polypyrrole using a chemical polymerization technique to give it conductive characteristics. The electro-conductive properties are obtained by using the double in–situ oxidative polymerization of pyrrole. The electrical properties of conductive samples are studied using the Van Der Pauw method as a measuring method. The conductive leather transformation process was carried out during the 2018-2020 period, and the conductive leather samples were preserved in room conditions until the year 2023. The effect of natural ageing on the electro-conductive properties of conductive leather is the focus of this research. The results show that environmental factors influence polymer breakdown and stability, by causing an increase in electrical resistance. The changes in electrical surface resistance, as the effect of the ageing factor, vary from 39.8% to 129.9%. Those changes in electrical resistance indicate that ageing is one of the major concerns in the electrical properties and stability of conductive leather samples, so the performed measurements have importance in providing information for the researchers and designers regarding the conductivity changes over time as a result of natural ageing, which would like to work with conductive leather on smart products.

Mechanical stress state consideration for enhanced electromigration life prediction in aluminum wire bonds

In this study, 5 [mil] aluminum wire bonds are subjected to elevated ambient temperatures, current densities, and mechanical stresses using a novel accelerated testing mechanism. Failure of a wire bond in this study was a 10 % increase in electrical resistance. Temperature coefficient of resistance experiments in this study identified the wire temperatures resulting from joule heating and thermomechanical stress evaluations were completed using ANSYS to extract relevant stresses occurring at each experimental condition. Collection of the failure data and analysis of the results indicate that mechanical stress interacts with current density and that the introduction of externally applied mechanical stress reduces the lifetime of a wire bond. Comparisons have been drawn between time to failure estimates for Black's equation for electromigration and three model forms developed from the results of this study. The comparison indicates that Black's equation is insufficient when mechanical stresses interact with current density and that mechanical stress ought to be considered in the future when completing reliability evaluations for wired interconnects in high-temperature systems.

Investigating the Influence on the Electro-Conductive Properties of Leather as a Result of Natural Aging

Conductive leather and its use in smart products have found a lot of interest. Leather behaves as a good insulator, so it was treated with electrically conducting polypyrrole using a chemical polymerization technique to give it conductive characteristics. The electro-conductive properties are obtained by using the double in–situ oxidative polymerization of pyrrole. The electrical properties of conductive samples are studied using the Van Der Pauw method as a measuring method. The conductive leather transformation process was carried out during the 2018-2020 period, and the conductive leather samples were preserved in room conditions until the year 2023. The effect of natural ageing on the electro-conductive properties of conductive leather is the focus of this research. The results show that environmental factors influence polymer breakdown and stability, by causing an increase in electrical resistance. The changes in electrical surface resistance, as the effect of the ageing factor, vary from 39.8% to 129.9%. Those changes in electrical resistance indicate that ageing is one of the major concerns in the electrical properties and stability of conductive leather samples, so the performed measurements have importance in providing information for the researchers and designers regarding the conductivity changes over time as a result of natural ageing, which would like to work with conductive leather on smart products.

Effects of shrinkage-reducing admixtures and expansive agents on the self-sensing behavior of nanomodified cement-based materials

Shrinkage control is needed to ensure an appropriate installation of cementitious sensors used in the Structural Health Monitoring of concrete elements. However, the effects of shrinkage-reducing admixtures (SRAs) and expansive agents (EAs) on the self-sensing properties of the cementitious sensors is still unknown. Therefore, the present work evaluated the effects of a SRA and EAs based on calcium oxide (CaO) or calcium sulfoaluminate (CSA) on the shrinkage behavior, microstructure, self-sensing response and compressive strength of mortars containing carbon black nanoparticles (CBN). The SRA provided shrinkage reductions up to 47.4%. CaO-based EA and CSA-based EA provided an expansive behavior. The admixtures caused increases in electrical resistivity and gauge factor up to 37.1% and 71.0%, respectively. In contrast, they did not cause statistically significant changes in stress sensibility and compressive strength. A microstructural analysis suggested that portlandite and ettringite crystals provided by the inclusion of EAs caused interruptions in conductive paths inside the mortars, which decreased contact conduction mechanisms and increased the amount of insulating tunneling gaps between CBN, enhancing the gauge factor of the materials. Therefore, shrinking control admixtures were found to be promising alternatives to enable the dimensional compatibility between cement sensors and old concrete elements, and increase the self-sensing properties of smart cementitious composites.

Effect of induced defects on conduction mechanisms of noble-gas-implanted ScN thin films

Noble-gas implantation was used to introduce defects in n-type degenerate ScN thin films to tailor their transport properties. The electrical resistivity increased significantly with the damage levels created, while the electron mobility decreased regardless of the nature of the ion implanted and their doses. However, the transport property characterizations showed that two types of defects were formed during implantation, named point-like and complex-like defects depending on their temperature stability. The point-like defects changed the electrical conduction mode from metallic-like to semiconducting behavior. In the low temperature range, where both groups of defects were present, the dominant operative conduction mechanism was the variable range hopping conduction mode. Beyond a temperature of about 400 K, the point-like defects started to recover with an activation energy of 90 meV resulting in a decrease in resistivity, independent of the incident ion. The complex-like defects were, therefore, the only remaining group of defects after annealing above 700 K. These latter, thermally stable at least up to 750 K, introduced deep acceptor levels in the bandgap resulting in an increase in the electrical resistivity with higher carrier scattering while keeping the metallic-like behavior of the sample. The generation of both types of defects, as determined by resistivity measurements, appeared to occur through a similar mechanism within a single collision cascade.

Electrical conductivity and heating performance of hybrid steel fiber-reinforced SCC: The role of high-volume fiber and micro fiber length

Recently, it has become very popular to develop electrically conductive concrete composites for active deicing and snow-melting of transportation infrastructure. These composites should have stable electrical conductivity and a uniform heating performance, as well as high mechanical and durability properties, for a sustainable solution. In this context, the main motivation of this study is to develop an electrically conductive hybrid steel fiber reinforced self-compacting concrete (HSFR-SCC) composite for ice and snow removal applications. The electrical conductivity and heating performance of self-compacting concrete (SCC) mixtures having different fiber volumes (1.00, 1.25, and 1.50%) and the combination of macro steel fiber with micro steel fibers having lengths of 13 and 6 mm as single and hybrid were experimentally investigated for the first time. For this purpose, a total of ten SCC mixtures were designed, one of which was non-fiber Control, the others had steel fiber volumes of 1.00, 1.25, and 1.50% and different fiber combinations. Workability (slump-flow, T500 and J-ring) tests on HSFR-SCC mixtures were performed with reference to EFNARC. Then, mechanical (compressive and flexural strengths), electrical resistivity, and heating performance tests of 90-day HSFR-SCC samples were carried out. Before the electrical resistivity and heating performance tests, HSFR-SCC samples were kept in an oven at 105 ± 5 °C for 24 h to measure their most critical state (dry) performance. Moreover, using multiple linear regression analysis, empirical equations and contour plots were developed to predict the electrical resistivity and temperature increase values of HSFR-SCC samples depending on fiber volumes and combinations. Considering the experimental results, electrically conductive HSFR-SCC mixtures with satisfactory workability and high strength were obtained. The addition of various volumes and combinations of steel fiber to SCC significantly improved the electrical conductivity and heating performance of the concrete, while the mixtures with hybrid fiber were the best for all fiber volumes. As for the different micro fibers added to the HSFR-SCC mixtures, the 13 mm length micro steel fiber was much more effective in improving the electrical resistivity and heating performance of the samples compared to the 6 mm length micro steel fiber. Also, it was found that the fiber-reinforced index of electrically conductive HSFR-SCC samples could be 0.87 for effective and efficient electrical conductivity.

The Effect of SiC and MgO Ceramic Reinforcements on the Mechanical Behavior and Electrical Properties of the Composite Structure in Al7075/SiC/MgO Hybrid Composites

In this study, certain technical properties of new generation aluminum-based composites, obtained by combining the Al7075 alloy widely used in the industrial field with two different ceramics, were investigated. For this purpose, SiC and MgO ceramics in particle form were reinforced into the Al7075 matrix material using powder metallurgy technique and composite structures were produced in three different reinforcement ratios. Measurements to determine electrical resistance and conductivity and bending and compression strength tests were performed on the obtained composite structures. The density and porosity amounts of the composite structures were also determined, and their microstructures were examined with a digital microscope. With the increase of SiC/MgO amount in the aluminum composite structure, the electrical resistance increased, and the conductivity value decreased. With the effect of SiC/MgO reinforcing materials, the density value of the composite structures decreased while the amount of porosity increased. The hardness values increased due to the effect of SiC and MgO ceramics in the structure. The bending and compression strength values initially increased and then started to decrease with the increase of reinforcement ratios. It has been determined that the formation of porosity in the composite structure negatively affects the mechanical behavior. The second important factor was evaluated to be the amount and shape of ceramic-based reinforcement particles in the structure. Due to the effect of SiC, which has very high electrical resistance, and MgO, which has dielectric properties, the electrical conductivity values of the composite structures decreased. The increase in electrical resistance and the decrease in electrical conductivity were directly proportional to the amount of ceramic-based reinforcement particles in the composite structure.

Parameters influencing the fracture of Mo films and their wider significance

Fragmentation testing has been used for decades to assess thin film fracture and delamination. Hooke’s law is generally used to determine a film fracture stress from the crack onset strain observed in micrographs or measured as an electrical resistance increase. While this method is in theory suitable in the elastic regime, it neglects important film characteristics, such as residual stress, microstructure, or film architecture. Thus, there is a need to improve fracture analysis using fragmentation to avoid significant errors in measuring fracture stress or apparent fracture toughness of thin films. In-situ X-ray diffraction fragmentation experiments can measure the film fracture stress even for individual layers being part of a multilayer. Which characteristics influence the apparent fracture behavior will be demonstrated on Mo thin films on polyimide.Graphical abstract

Distinct Organotypic Platforms Modulate Rainbow Trout (Oncorhynchus mykiss) Intestinal Cell Differentiation In Vitro.

In vitro organotypic cell-based intestinal platforms, able to faithfully recapitulate the complex functions of the organ in vivo, would be a great support to search for more sustainable feed ingredients in aquaculture. We previously demonstrated that proliferation or differentiation of rainbow trout intestinal cell lines is dictated by the culture environment. The aim of the present work was to develop a culture platform that can efficiently promote cell differentiation into mature enterocytes. We compared four options, seeding the RTpiMI cell line derived from the proximal intestine on (1) polyethylene terephthalate (PET) culture inserts ThinCert™ (TC), (2) TC coated with the solubilized basement membrane matrix Matrigel® (MM), (3) TC with the rainbow trout fibroblast cell line RTskin01 embedded within the Matrigel® matrix (MMfb), or (4) the highly porous polystyrene scaffold Alvetex® populated with the abovementioned fibroblast cell line (AV). We evaluated the presence of columnar cells with a clear polarization of brush border enzymes, the formation of an efficient barrier with a significant increase in transepithelial electrical resistance (TEER), and its ability to prevent the paracellular flux of large molecules but allow the transit of small compounds (proline and glucose) from the apical to the basolateral compartment. All parameters improved moving from the simplest (TC) through the more complex platforms. The presence of fibroblasts was particularly effective in enhancing epithelial cell differentiation within the AV platform recreating more closely the complexity of the intestinal mucosa, including the presence of extracellular vesicles between fibroblasts and epithelial cells.