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Combining multiple monitoring methods can improve the accuracy of coal damage and fracture behavior detection. In this study, nine coal samples, each with similar P-wave velocities and masses, were subjected to joint monitoring experiments involving multiple physical parameters. The acoustic emission (AE) and resistance information of coal samples were assessed from the initiation of loading to eventual failure under diverse uniaxial loading rates. The characteristic electrical and acoustic parameters were analyzed in combination with coal damage conditions. The results show that, throughout the loading process, resistivity declined gradually with escalation of coal strain, followed by an abrupt nonlinear increase. Deformation before failure reduced coal resistivity by up to 11.39%. As the coal crack area expanded, the resistivity post-failure reached threefold the initial value. The AE ring count peak value corresponded to crack growth, and the AE energy had a power law distribution feature. The frequency band effect of the AE peak frequency was significant, and shear cracks accounted for more than 80%. Resistance and AE ring count exhibited simultaneous responses to coal failure, and the characteristic parameters of acoustic-electrical behavior demonstrated consistent patterns for cracks induced by various loading rates. The time sequence characteristics of the RSD index, which quantified the degree of resistivity fluctuation, corresponded almost exactly to the development process of coal damage described by AE, and the peak value of this index corresponded to the AE event in the time scale. The overall fluctuation degrees in resistivity of coal samples with varying damage levels showed positive correlation with the AE ring count. An acoustic-electric method for characterizing coal damage is summarized, and corresponding resistivity characteristic parameters are proposed. These parameters have a significant response law to coal damage, which is helpful in supplementing a new index for early warning of geological disasters. [ABSTRACT FROM AUTHOR]

The electrical resistance variation of the Sn–20% Pb alloy melt subjected to ultrasonic vibration was investigated using four-electrode method. The modified energy band theory and cavitation dynamics simulation were employed to explain the experimental results. The ultrasonic vibration in the liquid disrupted the melt structure and enhanced the forced vibration of the atoms, resulting in a reversible liquid–liquid structural transformation and a sharp decrease in electrical resistance. The evolution of the optical microstructure suggested that the ultrasonic-induced refining and homogenizing effects of short-range ordered structures were time-sensitive. The numerical simulation of cavitation dynamics indicated that the structural variation was the substantial root for the electrical resistance change by ultrasonic irradiation, and the high energy required for the reversible structural variation was provided by the collapsing cavities. [ABSTRACT FROM AUTHOR]

The fabrication of ternary Cu–Mn–Al alloys through self-propagating high-temperature synthesis and their thermoelectric properties, such as electrical resistivity and the Seebeck coefficient in a wide range of temperatures, were studied. XRD analysis identified the Heusler compound Cu2MnAl in the synthesized compositions as a main precipitated phase. In addition, different secondary phases (Al2Cu, Cu3Al AlCu, and Mn) appear depending on an excess of aluminum or manganese in the green mixture. The magnetization (M–H) curves constructed for the studied alloys showed their weakly ferromagnetic behavior. [ABSTRACT FROM AUTHOR]

The progression of the electrical resistance of graphite foils during spark plasma sintering process (SPS) was investigated at constant temperature and pressure. The study applied various set-ups of the SPS device, and the electrical data used for the evaluation of electrical resistance (heating power and current) was obtained from the SPS apparatus in real-time. The contact resistance and resistance due to graphite foil/s was evaluated by subtracting the resistance of the single punch set-up from the set-up of two punches in direct contact and the set-ups with various graphite foils. The results showed that during the initial stages of sintering, set-up resistance increases with time and that, overall, set-up resistance increases with number of graphite foils. Both contact resistance and resistance due to graphite foils was found to decrease with sintering time. In contrast to previous conceptions, the electrical resistance of graphite foils changes in response to sintering conditions during the SPS process. [ABSTRACT FROM AUTHOR]

The effect of copper (II) sulfide (CuS) addition on the superconductivity of (Bi1.6Pb0.4)Sr2Ca2Cu3O10 (CuS)x (x = 0–1.5 wt%) is reported. All samples were prepared via the co-precipitation technique. The XRD patterns revealed that the formation of Bi-2223 phase was not affected by the CuS addition. The temperature-dependent resistance measurements showed a metallic normal state behavior for all samples, with onset transition temperatures Tc onset between 109 and 118 K and zero transition temperatures Tc zero between 96 and 101 K. The intragranular and intergranular diamagnetic transition, intrinsic and coupling peak temperatures, the onset temperature of grain decoupling and the Josephson phase-locking temperature of (Bi1.6Pb0.4)Sr2Ca2Cu3O10 were not suppressed at lower CuS additions (x ≤ 0.2 wt%) but further CuS additions (x = 0.8–1.5 wt%) severely suppressed these properties. The highest Josephson current (10.82 μA) and Josephson energy coupling (22.22 meV) were exhibited by the non-added sample. The volume fraction of the grains decreased when CuS was added which indicated that the intergranular contribution was enhanced as shown by the AC susceptibility curves for all added samples. The highest transport critical current density, Jct at 40 K was for x = 0.2 wt% sample (4713 mA cm−2). The effect of internal lattice strain on the transition temperatures was also discussed. This work showed that lower addition of CuS could enhance the connectivity between the grains and enhance flux pinning. [ABSTRACT FROM AUTHOR]

We investigated semiconductor composite materials of the AlN–50% SiC–Y3Al5O12 system, obtained by free sintering, which exhibit a high level of microwave absorption of 4.6 dB/mm. The activation energy values of electrical conductivity (Ea) for the obtained composites were calculated within the temperature range of 20–800°C. At temperatures close to room temperature (20–150 °C), Ea ranges from 0.120 to 0.075 eV and increases to 0.270–0.275 eV as the temperature rises to 350–800°C. The determined photon energy values of the electromagnetic wave, in the frequency range from 1 to 100 GHz, are from 4.13 × 10–6 to 4.13 × 10–4 eV. Using quantum electrodynamics at the atomic level, we described the process of microwave radiation absorption in the AlN–SiC semiconductor composites. Low-energy photons of electromagnetic waves incident on the surface of the AlN–SiC composite transfer their energy to the conduction electrons in the near-surface layers of the SiC phase and are absorbed by them. The conduction electrons emit photons at the same frequency of the electromagnetic wave, predominantly into the same SiC grains, within 10–8 s. This interaction results in the absorption of electromagnetic radiation, leading to the dissipation of wave energy and subsequent heating of the entire composite: initially, the SiC phase particles and, subsequently, the AlN grains. [ABSTRACT FROM AUTHOR]

We consider a model of current distribution in a tungsten sample and a vapor layer produced when the surface is heated by an electron beam. The model is based on solving electrodynamic equations and a two-phase Stefan problem in cylindrical coordinates. Based on the temperature distribution in the computational domain, the electrical resistance and thermopower are calculated via an integral over the electron energy at each grid node. The electromagnetic field configuration is a possible source of rotation of the substance, which is observed in experiments. The simulation results demonstrate the role of thermionic emission and the way of model development. The model parameters are taken from experiments at the Beam of Electrons for materials Test Applications (BETA) facility created at the Budker Institute of Nuclear Physics of the Siberian Branch of the Russian Academy of Sciences. [ABSTRACT FROM AUTHOR]

In the paper an experimental study of the influence of two types of multiwalled carbon nanotubes (MWCNTs) obtained on Ni/0,16MgO (MWCNTs-1) and Co–Mo/Al2O3–MgO (MWCNTs-2) catalysts with micro-sized metals (12–60 μm) on the change of structural and electro- and thermophysical properties of organosilicon elastomer Silagerm 8030 was carried out. It was found that micro-sized particles of aluminium (Al) and bronze (Br) mixed with MWCNTs improve the electrical and thermal conductivity of the elastomer. At the same time, the addition of micro-sized Al in the form of powder to the elastomer matrix resulted in the formation of elongated formations from particles of different sizes up to 60 μm, while Br was characterized by spherical inclusions from particles with sizes from 12 to 30 μm. The analysis of elemental composition showed that the composite with MWCNTs-1 and Al has in its composition, in addition to Al, nickel (Ni) associated with the catalyst particles which in the process of synthesis intercalated into the structure of MWCNTs-1. The presence of silicon (Si), is related to the chemical composition of the elastomer, which has polar Si–O bonds, and carbon (C) corresponds to MWCNTs. The composite containing MWCNTs-2 (2 wt %) with Br (3 wt %) had the maximum thermal conductivity of 0.215 W/(m °C) and the minimum electrical resistivity of 25.784 kΩ at 3×106 Hz. [ABSTRACT FROM AUTHOR]

The process of precipitation of Al3Zr particles in cast Al–(0.25–0.4) wt % Zr alloys manufactured by the induction casting method is studied. The effect of zirconium concentration on the structural parameters, hardness, and specific electrical resistance (SER) of cast alloys is investigated. The dependences of hardness and SER on the time of cast alloys annealing at 500°C are plotted. The parameters of the Johnson–Mehl–Avrami–Kolmogorov equation for alloys with different Zr content are determined. The optimal regimes of cast ingot aging are found. Fine wires with ∅0.3 mm are manufactured by the drawing method; their strength, SER, and hardness are studied in the initial state and after heat treatment. The tests of thermal stability of wires are carried out according to the state standard GOST R MEK 62004–2014. [ABSTRACT FROM AUTHOR]

The results of measurements of the frequency dependence of the active resistance of a circular cross-section of aluminum and copper conductors with a various diameter in a wide frequency range from 20 Hz to 2 MHz are presented. Using the skin effect simulation we show that for all types of wires an increased active resistance observed, compared to the theoretical values in the frequency range above 200 kHz, where the skin layer thickness becomes less than 200 μm. This phenomenon may be associated with the manufacturing process of a metal wire by drawing through a die, when defects are formed in the near-surface layer, leading to its increased resistivity. [ABSTRACT FROM AUTHOR]

Uncertainty about the geometry of jet grouting columns is a serious challenge to the efficiency of jet grouting technology. If this challenge can be met, jet grouting can become an efficient method of soil improvement. One proposed approach is measurement based on changes in the electrical resistivity between the column and surrounding soil. This approach is non-destructive, easy to use, fast and accurate. This paper reviews jet-grouting methods using the experimental research approach and reports on the design and construction of a probe equipped with ring electrodes that is suitable for measurement of the column diameter. The approach is based on the geoelectric method and Wenner theory. The probe was field tested on jet-grouting columns in a project in Bandar-e Gaz. The probe results were validated by visually observing the dimensions of the excavated column. The results showed that the probe performed well. The device measured a 90-cm column as being from 81 to 88 cm with an error of about 10%. The method of measuring the difference in electrical resistance was shown to be an accurate approach to solving the problem of uncertainty in the geometry of jet-grouting columns. [ABSTRACT FROM AUTHOR]

Electrical resistance measurement is central to materials characterization, circuit analysis and resistance-based sensing. Resistance measurement involving the two-probe method (involving two electrical connections) is known to overassess the resistance, due to the electrode-specimen contact resistance. Resistance measurement involving the four-probe method (involving four electrical connections) is advantageous in that it essentially excludes the contact resistance at the connection-specimen interface. Nevertheless, the two-probe method is widely used, because of the simplicity of having only two connections. In the two-probe method, the current passes through the specimen and connections. The connection-related stray inductance is found in this work to cause large additional overassessment of the two-probe resistance when the electrical connection configuration entails current direction changes. The connections pertain to electrical leads and clips. The inductance increase due to a current direction change is in line with Faraday's law. Mere constriction or spreading of the current due to the connections also increases the inductance, but it does not influence the two-probe resistance. The inductance and two-probe resistance increase with the lead length because of the connection-related inductance, not because of the negligible increase in the lead resistance. An inductance increase of ≤ 80% causes a two-probe resistance increase of ≤ 278%. The specimen in this work is aluminum. It does not need to be magnetic. The connections in this work are also not magnetic. This inductance-related source of two-probe resistance overassessment is reported here for the first time. [ABSTRACT FROM AUTHOR]

The dependence of the electrical resistance of a volumetric homogeneous conductor on the area of electrical contacts has been studied by computer modeling methods. To describe this dependence, simple analytical models are proposed, which are suitable for engineering calculations. The problem of resistance of a multilayer structure with a small contact is considered and solved. [ABSTRACT FROM AUTHOR]

The results of work on the creation of an efficient and economical method, as well as the manufacture and testing of an installation for non-destructive quality control of baked anodes of aluminum electrolytic cells. The installation uses the method of measuring the electrical resistance of the anode and building its calculation model with known data on its geometry and resistivity, as well as the geometry and coordinates of internal defects. In this case, a series of calculations is performed to obtain a 3D matrix of amplitudes and directions of the vectors of the calculated strengths or inductions of the electromagnetic field at points located near the outer surface of the anode. To do this, at least two electrically conductive contacts are placed at these points, passing a given amount of electric current through the anode. Also, at least one sensor is placed near the outer surface of the anode and the amplitude and direction of the magnetic field intensity or induction vectors are measured and displayed in the form of a 3D matrix of the measured intensity or magnetic field induction vectors. After that, the 3D matrices of the calculated and measured vectors of the strength or induction of the magnetic field are compared at the same points located near the outer surface of the anode and, based on these results, the sizes and coordinates of internal defects are determined. The technical result of the implementation of the proposed method is to increase the accuracy, reliability and reliability of determining the location of defects in baked anodes. The installation was tested in laboratory and industrial conditions, which showed good agreement between the results obtained and the data obtained by destructive testing. The entire procedure for checking the quality of one anode took 45–50 s. As a result of preliminary tests, it was determined that out of 100% of the anodes approved for use by the manufacturer, 13.5% were rejected by NDF testing. During research in the Siberian Federal University laboratory, it was found that the accuracy of detecting defective anode blocks using NDF was 82%. Industrial test results of the installation made it possible to divide all anode blocks into 4 classes based on quality, and the validity of this division was confirmed by destructive testing tests. [ABSTRACT FROM AUTHOR]

We measured the temperature dependence of the resistance in thinned samples of a layered transition metal dichalcogenide 1T-TiSe2. As a result, a thermal hysteresis of resistance was discovered in most samples with a thickness of 10 μm or less, but not in samples thicker than 100 μm. The onset temperature of this hysteresis was almost the same as the onset temperature of the charge density wave (CDW) transition, suggesting that this hysteresis is related to the CDW. All the samples with hysteresis exhibited one or a few jumps of resistance in the 110–190 K range in cooling. Moreover, the hysteresis was related not only to the history of temperature below the CDW transition temperature, but also to that above the transition temperature. To interpret these anomalous results, we discuss the effect of impurities on the domain structure of the CDW. [ABSTRACT FROM AUTHOR]

We measured the temperature dependence of the resistance in thinned samples of a layered transition metal dichalcogenide 1T-TiSe2. As a result, a thermal hysteresis of resistance was discovered in most samples with a thickness of 10 μm or less, but not in samples thicker than 100 μm. The onset temperature of this hysteresis was almost the same as the onset temperature of the charge density wave (CDW) transition, suggesting that this hysteresis is related to the CDW. All the samples with hysteresis exhibited one or a few jumps of resistance in the 110–190 K range in cooling. Moreover, the hysteresis was related not only to the history of temperature below the CDW transition temperature, but also to that above the transition temperature. To interpret these anomalous results, we discuss the effect of impurities on the domain structure of the CDW. [ABSTRACT FROM AUTHOR]

The advantages of deep arc reduction (DAR) technology are demonstrated as applied to converting useful elements inherent in metallurgical wastes into iron–carbon melts for their refining, deoxidative alloying, homogenization and heating. The proposed method can be used in mini- and microplants as an alternative to the traditional methods of out-of-furnace processing. The effect of the design and composition of the combined iron-graphite electrode (CIGE) as a part of ore reduction blocks intended for the DAR recovery of useful elements exerted on the DAR efficiency has been studied. The values of current density, CIGE diameter, number and diameter of technological holes in its steel tube that are acceptable for the successful implementation of the process have been established. The effect of electrode mixture composition on the electrical resistivity thereof and the rate of CIGE consumption is demonstrated. Technological recommendations are proposed for optimizing the parameters under study. [ABSTRACT FROM AUTHOR]

Continuous laser lap welding for a dissimilar combination of aluminum (Al) and copper (Cu) was achieved successfully. The successful welding was achieved by varying laser power between 500 and 900 W with an interval of 100 W, whereas the variation in welding speed was maintained between 10 and 45 mm/min with an increment of 5 mm/min. A combination of various laser power and weld speed generated a broad range of volume energy inputs, among which acceptable welding with no macroscopic defect could only be generated between 1.81 and 7.64 kJ/mm3. The volume energy required to achieve successful welding increased with the increase in bottom Cu sheet thickness. The joint's mechanical properties were significantly enhanced for thicker bottom Cu sheets as the welding was carried out at a higher volume of energy achieving higher depth of penetration of 0.65 mm in case of 1.5-mm bottom Cu sheet thickness. Lap shear tensile tests and Vickers's microhardness testing confirmed the abovementioned results as the highest breaking load of 373.79 N, and Vicker's hardness of 350 Hv inside Al and 750 Hv inside Cu was obtained. Furthermore, SEM results on the weld cross sections showed that welds with thicker bottom Cu sheets exhibit a higher penetration depth and lower top weld bead. Detailed electron microscopy and spectroscopy revealed the formation of hard intermetallic compounds (IMCs) inside the weld zone due to the Cu diffusion inside the weld. They correlated well with the measured mechanical and electrical properties. Electron back-scattered diffraction (EBSD) revealed a sudden concentration of high-angle boundaries (HAB) inside the weld, confirming the presence of hard IMCs. Inside the weld, most of the grain boundaries transformed into HAB, which explains the joints' enhanced mechanical properties. [ABSTRACT FROM AUTHOR]

The search for new types of resistors that could potentially be used for long–term storage of electrical resistance values with the highest attainable accuracy has always been an urgent task of metrology. In this paper, we have studied the problem of choosing a resistor for transmitting and storing a unit of electrical resistance when creating an Ω standard based on the quantum Hall effect in the time interval between reproductions of a unit. The choice of C5–60 resistors, which were not originally intended for use as standards of higher levels of the electrical resistance verification circuit, is substantiated. In 1990–2022 detailed experimental studies, including studies of long–term stability, of C5–60 type resistors have been carried out. Some of the investigated resistors are included in the State secondary standard of electrical resistance unit in the range of values from 0.1 Ω to 13 kΩ based on the quantum Hall effect. Comparisons of the investigated resistors with resistance measures traditionally used to create standards for the unit of electrical resistance are carried out. It has been established that C5–60 resistors have a low temperature coefficient of resistance, they are easy to stabilize using a thermostat without a temperature–controlled oil bath. The long–term stability of the C5–60 resistors turned out to be uniquely high and allows these resistors to be used as discharge standards for storing a unit of electrical resistance. [ABSTRACT FROM AUTHOR]

In this research, the effect of per pass applied strain on the mechanical and electrical properties of commercial pure copper in twist extrusion process was investigated. For this, two dies with different twist angles of 37° and 56° (called dies A and B, respectively) were manufactured to perform the process in 8 passes. Finite element simulation was used to find the average per pass applied strain in the investigated dies. Compressive testing and hardness testing were used to assess the mechanical properties of the samples processed up to different passes. Also, the optical micrographs accompanying with SEM images were prepared from the samples to explain the effect of the applied strain on the grain refinement and the consequent mechanical properties. Comparison of the samples processed in dies A and B with the same accumulated strain showed that reducing per pass applied strain causes the improvement in the mechanical properties of the samples. The results also showed that the electrical resistance of the samples changes in proportion to the changes in the mechanical properties. [ABSTRACT FROM AUTHOR]

Dysprosium nanolayers differing in the thickness are prepared by magnetron sputtering on Al2O3(R) substrates using Co90Fe10, β-Ta, and Nb buffer layers. The correlation between the crystallographic texture type and peculiarities of temperature dependences of electrical resistance of polycrystalline dysprosium films is studied. It is found that, in the case of deposition of Dy directly on Al2O3(R), a two-component texture forms in the rare-earth metal layer. One of the components is characterized by the hexagonal axis parallel to the film plane, whereas the other component is characterized by the axis perpendicular to the film plane. In the case of deposition of Dy on the β-Ta buffer layer, the microstructures of Al2O3 and Dy are shown to demonstrate the matching through β-Ta, and the perfection of the two-component texture increases. In the antiferromagnetic state, the texture components become "phases" differing in the orientation of magnetic helicoid axis, and the anitiferromagnetic ordering occurs at different temperatures. [ABSTRACT FROM AUTHOR]

This research paper presents the results of an investigation into the formulation of silver conductive ink for use in inkjet printing. The aim of the study is to develop an environmentally friendly and cost-effective ink using a simple and scalable method. To achieve this, silver nanoparticles (AgNPs) were synthesized through a co-reduction approach using starch and temperature, and their physical and chemical properties were examined. The silver conductive ink was prepared with different amounts of AgNPs, using a sodium alginate/ Polyethylene glycol (Na-alginate/PEG) suspension matrix. In order to ensure the suitability of ink for the inkjet printing technique, the viscosity measurement was performed. According to the results, three formulations were produced and printed on Polyurethane-coated polyester (PU-coated PET) by a syringe disposition system. The electrical measurements showed that the minimum sheet resistance of printed patterns prepared with 3%wt of AgNPs was 0.008 Ω/cm and 0.205 Ω/cm with 20wt% and 40wt% of Na-alginate, respectively. These values are sufficient to power an LED connected to the printed coated fabric. Furthermore, the electrical properties of the printed patterns remained acceptable for electronic applications even after mechanical stress up to 20%. This research has the potential to pave the way for several future applications of printed electronic textiles where environmentally friendly, low-cost, and higher electrical performance inks are required. [ABSTRACT FROM AUTHOR]

The long-term relaxation of large-scale heterogeneities in aluminum–rare earth metal (REM) melts with a REM content of 5–10 at % was observed earlier on measuring viscosity and density but did not manifest itself on measuring electrical resistance and magnetic susceptibility. This behavior could be related to both the specifics of the measured properties and the sample sizes. In the case of viscosity and density measurements, they are much larger: 12–15 g for a cylindrical crucible diameter of ~15 mm for viscosity and density measurements and smaller than 1 g for a crucible diameter of 6 and 4 mm for electrical resistance and magnetic susceptibility measurements, respectively. To solve this problem, we measure the time dependences of the electrical resistance of the Al91La9 melt at 1060°C for samples of various sizes, namely, for standard (crucible diameter of 6 mm) and large (crucible diameter of 10.5 mm) samples, using the rotating magnetic field method. When the sample size increases, the random measurement error increases; therefore, we have to take additional measures to stabilize the electric current in the coils creating a magnetic field. When the sample mass increases to 2.15 g at a crucible diameter of 10.5 mm, a large-scale heterogeneity is found to occur during melting. It is interpreted as a compact "cloud" of intermetallic microparticles surrounded by a melt with a high REM content. The sample relaxes to an equilibrium homogeneous state in a few hours. To accelerate the process, an additional action is required: heating to a high temperature, about 1500°C, which reduces the time to less than one minute. This heterogeneity does not occur in small samples (0.7 g at a crucible diameter of 6 mm). This heterogeneity is likely to appear due to a REM atom flux to the surface and the reverse flux of aluminum atoms into the volume during crystallization, which is similar to segregation during the crystallization of cast iron and steel. Our measurements make it possible to estimate the scale of the appearing heterogeneities, which corresponds to the large sample size. [ABSTRACT FROM AUTHOR]

Electrically conductive composite materials based on polybenzimidazole and aromatic polyamide matrices with single-walled carbon nanotubes (SWCNTs) are studied. Composites are obtained from SWCNT dispersions in solutions of polybenzimidazole and aromatic polyamide in N-methyl-2-pyrrolidone by the same procedure. Composites based on the poly-2,2′-p-oxydiphenylene-5,5′-dibenzimidazole (OPBI) matrix with a SWCNT concentration less than 1 wt.% are shown to be not electrically conductive unlike those based on the poly-m-phenylene-isophthalamide (MPA) matrix (electrically conductive even with a SWCNT concentration of 0.1 wt.%). This feature is related to different morphologies of the composites: in OPBI-based composites, nanotubes are more effectively separated by the polymer matrix due to the π–π interaction of OPBI macromolecules with SWCNTs. The microstructure is analyzed by scanning and transmission electron microscopy. It is revealed that in the case of the OPBI- matrix, nanotubes are separate SWCNTs or bundles with a smaller diameter and a more uniform volume distribution compared to the MPA-matrix. This feature of the morphology is reflected in temperature dependences of the electrical resistance measured from room temperature down to 4.2 K. In the case of the OPBI-matrix, the electrical resistance changes more with temperature, which also indicates the better separation of SWCNTs in the OPBI- matrix than in the MPA one. [ABSTRACT FROM AUTHOR]

The results of calculations of the electronic structure, thermoelectric characteristics, and experimental study of the thermoelectric, electrical, and optical properties of Mn2MeAl Heusler alloys (Me = Ti, V, Cr) are presented. The agreement between theory and experiment in the sign of the Seebeck coefficient is shown. The obtained pattern of the band spectrum allows us to qualitatively explain the peculiarities of the temperature dependences of the electrical resistance and the permittivity dispersion. [ABSTRACT FROM AUTHOR]

Copper is the forefront of the fundamental metals used in various industries. It is utilized as bulk or electrodeposited on PCBs or interconnects. However, poor corrosion resistance and hardness reduce copper performance and limit its applicability in the fields that require mechanical strength, such as probing applications. Facile electrochemical deposition of Cu(Ag) films was examined in a deep eutectic solvent known for its green nature. SEM–EDS technique was applied for morphostructural and crsytal plane analysis. XRD analysis revealed Cu3.96Ag0.04 phase, and 2% Ag was identified in the Cu(Ag) film in EDS. Four-prope point resistivity analysis was performed via galvano-impedance spectroscopy. Obtained resistivity value of 5 µm thick Cu(Ag) coating was lower than the compliance limit of International Technology Roadmap for Semiconductors. Corrosion analysis was carried out via electrochemical impedance spectroscopy technique, and Cu(Ag) films demonstrated better resistance. Hardness tests also revealed that Cu(Ag) was approximately two times harder than Cu. [ABSTRACT FROM AUTHOR]

A method for introducing reinforcing microparticles of boron nitride, BN, into an aluminum melt A0 is described. Reinforcing particles in the composition of tablets pressed in a mixture with aluminum microparticles were introduced into liquid aluminum. The aluminum was in a crucible and was intensively stirred by a traveling and rotating magnetic field. Subsequently, the melt crystallized directionally, after which its structure was studied using an electron microscope FEI Quanta 650FEG with an x-ray microanalysis EDAX Octane Elite attachment and an optical microscope Hirox KH-7700. The specific electrical resistance of the obtained composite and its mechanical characteristics were also determined in the experiment. In this work, the electromagnetic and hydrodynamic characteristics of the stirred melt were calculated numerically (ANSYS MAXWELL 3D and ANSYS CFX packages, respectively, were used). Patterns of the velocity fields and of the shapes of the free surface during the introduction of particles into the liquid metal are presented. Experiments have shown that aluminum composites filled with nanoparticles differ in physical properties from aluminum composites with microparticles. With an increase in the concentration of BN nanoparticles (100 nm) in aluminum A0 from 0 to 1.3%, its electrical resistance increases by 4%, and the ultimate strength becomes higher by 13%. With an increase in the concentration of BN nanoparticles (3–5 μm) in aluminum A0 from 0 to 1.3%, its electrical resistance increases by 6.8%, and the ultimate strength, respectively, only by 4%. The experiment showed that an increase in the percentage concentration of reinforcing nanoparticles in aluminum leads to a faster increase in the ultimate strength and to a slower increase in the electrical resistivity than with the introduction of reinforcing microparticles. [ABSTRACT FROM AUTHOR]

A three-fraction composition of the ceramic forming mass is developed for preparing energy-intensive resistors based on electrocorundum powders with grain size F 120, F 400 and a finely milled electrically conductive fraction from a colloid-graphite preparation of the S-1 brand. In order to bind grains when forming a workpiece an aluminum chromophosphate binder (ACPB) is used, which makes it possible to prepare unfired shrinkage-free objects. Components of the molding mass are mixed and pressed into semi-finished products. For comparison the structure and composition of a resistor of the HVR International company is analyzed. The effect of compaction pressure of the compositions developed on the amount of electrical resistance and the density of the material is studied. Abroad range of electrical resistance is achieved by changing the content of colloidal nano-size graphite. Based upon colloidal graphite and ACPB masses are obtained with reduced contact resistance. [ABSTRACT FROM AUTHOR]

Experimental data on the electrical resistance of aluminum under shock compression are analyzed. The electrical resistance of two types of aluminum foil located in dielectric materials with different shock impedances is measured by the electrocontact method. The resultant dependences of the electrical resistance of aluminum on the shock wave pressure are monotonically increasing functions of pressure. However, the dependence of the specific electrical resistance of aluminum on the shock wave pressure can be monotonic (foil in Plexiglas) or nonmonotonic (foil in fluoroplastic). In the latter case, the specific electrical resistance first slightly decreases with an increase in pressure and then increases. This behavior can be explained by the competing effects of compression and temperature heating on the specific electrical resistance. Due to shock compression of metal foil in the dielectric with a smaller shock impedance (Plexiglas), the measured electrical resistance is greater than that in the dielectric with a greater shock impedance (fluoroplastic). This result is caused by the greater temperature heating of metal foil in Plexiglas. The reasons for the qualitative difference in the behavior of the specific electrical resistance of metal under static and dynamic compression are discussed. [ABSTRACT FROM AUTHOR]

High-temperature composite materials comprising single-walled carbon nanotubes embedded in a polybenzimidazole (PBI) polymer matrix with a weight percentage of nanotubes from 1 to 5% were prepared and characterized. Film composite samples were prepared by flow-coating from dispersions of nanotubes in 2% PBI solution in N-methyl-2-pyrrolidone. The temperature dependences of electrical resistance of the composites were studied in the range from room temperature to 300°C in a high vacuum at a pressure less than 1 × 10–3 Pa. The first heating cycle to 300°C gave rise to an increase in room-temperature electrical resistance of the samples due to the desorption of oxygen from the nanotubes. For the composites containing 5 and 1% nanotubes, the change was about 1.4 and 500 times, respectively. This increase was reversible: when the samples were transferred to the ambient air, the electrical resistance relaxed to its initial value. The thermal stability of the composites was proved by the repeatability of the subsequent heating cycles and by thermogravimetric analysis. [ABSTRACT FROM AUTHOR]

A composite consisting of 80 mol % α''-Cd2.76Mn0.24As2 and 20 mol % MnAs has been synthesized and characterized by X-ray diffraction, differential thermal analysis, and microstructural analysis. The results demonstrate that the composite is a soft ferromagnetic material with a Curie temperature of 328 K. In the temperature range 4–300 K, its electrical conductivity shows metallic behavior. The composite has a high positive magnetoresistance, up to 600% in a magnetic field of 8 T. The nature of its magnetoresistance is determined by the Lorentz force, which suppresses the effect of the spin magnetic moments of the MnAs ferromagnet. Owing to the linear behavior of the temperature and magnetic field dependences of its electrical resistance, the composite is of practical interest for use as a material for temperature and magnetic field sensors. [ABSTRACT FROM AUTHOR]

In order to ensure the service reliability of flexible electronic products, flexible electronic interconnection wires need to have good conductivity and good resistance to deformation and fatigue. In this study, multiscale silver nanoparticle conductive inks were prepared by a one-step microwave approach for printing flexible silver wire. The silver inks with different sizes of silver particle distribution were prepared by adjusting the content ratio of silver nitrate, polyvinyl pyrrolidone, and ethylene glycol in a microwave reaction. The electrical and mechanical properties of the silver wire samples printed by the different inks were investigated. The prepared multiscale silver ink with larger average size of silver particles also had a greater size difference between silver particles, and the printed silver wire obtained a denser microstructure and had lower resistivity after hot-pressing sintering. However, the silver wire printed by multiscale silver inks with large average particle size was not conducive to improving the mechanical reliability. Also, silver wire consisting of particles of small average size with high porosity resulted in low bonding force between particles and reduced its mechanical reliability. Based on the investigation, a proper content ratio of silver nitrate, polyvinyl pyrrolidone, and ethylene glycol is recommended for preparing multiscale AgNP conductive ink to obtain printed silver wire with good electrical and mechanical properties. [ABSTRACT FROM AUTHOR]

The safety of bridge structures in operation should be ensured by periodic inspections and control checks. During the inspection of structures, the operational reliability of transport structures is assessed, and recommendations are made to eliminate the detected defects. In the case of imperfect methods for monitoring the stress state of load-bearing elements, unnecessary repairs can be assigned and performed, which can lead to an increase in the risk of accidents and inefficient use of budget funds. To date, the determination of the stress state is not included in the list of works performed during a detailed inspection of cables. This is caused by the low degree of study of existing nondestructive testing methods, the lack of developed and normatively fixed methods for their application, and a number of other reasons, including high labor intensity, low accuracy, narrow range of application and others. The main method used at the time of writing, a nondestructive method for monitoring the stress state of steel wires of cable ropes, is considered. At present, one of the most reliable and technologically simple methods for obtaining transmission and processing is an electrical signal. Its advantages make it possible to easily and efficiently inspect the ropes from different sides, which is very important when designing the device. The method of nondestructive testing of stress in steel cables is investigated. The dependence between the electrical resistance of steel measured on alternating current in the surface layer is determined. The results show that the violation of the integrity of the cables provides an electrical signal, the value of which depends on the state of each cable of the rope, the design of the rope, and the level of signal change that occurs in the event of damage to one of the cables. The factors influencing the dependence of electrical resistance on the mechanical parameters of the cable rope are revealed. Practical recommendations for the use of the method to control the stress state of the operated ropes are formulated. The aim is to improve the reliability, operational safety and service life of cable-stayed bridges by using electrical resistance to monitor the mechanical parameters of cable ropes. Using calculations in electrical engineering, a mathematical model is built, a method of its analytical solution in closed form is formulated, and the dependence of the distribution of stresses and currents in the rope on its parameters is investigated. The solutions for the rope with intact and damaged rope are obtained. The results allowed us to formulate requirements for the system, increased reliability, and control of the condition of the cable rope. Electrical signals can be used as diagnostic parameters in the control of ropes by a special system for detecting a gap in the rope. [ABSTRACT FROM AUTHOR]

Electrophysical properties of nanostructured (Ni80Fe20)xAu1-x thin films containing from 20 to 52 at.% of Au were investigated. All samples are characterized by metallic behavior upon annealing within the temperature range from 300 to 750 K. It was demonstrated that the resistivity is sensitive to the composition of the samples. Their value for the sample with 20 at.% of Au differs five times in comparison with the sample with 52 at.% of Au. The slope of the temperature dependence of resistivity depends on the composition of the samples too. This is caused by the effectiveness of electron–phonon interaction and peculiarities of the morphology of the samples. The temperature coefficient of resistance takes a positive value, has an order of 10−3 K−1, and grows with an increase of Au content. [ABSTRACT FROM AUTHOR]

In this study, resistive-type stretch sensors based on embroidered conductive threads were investigated to determine the best combinations of various conductive threads and fabrics, as well as the ideal embroidery patterns and their optimal geometric parameters. Among various conductive threads, a silver-plated nylon fiber of 280 denier was selected as the best conductive thread, because it featured the highest gauge factor and excellent stretchability and reliability. Among the various tested fabrics, the poly fine brushed knit fabric could endure high repetitive stretching without any permanent deformation, thus guaranteeing an apparent electrical resistance-strain curve. Zigzag, couching, overcasting, and decorative patterns were embroidered on this poly fine brushed knit fabric using the 280 denier silver-plated nylon fiber. The electrical resistance curves of the embroidered conductive threads were measured as functions of the applied strain and frequency. The zigzag pattern exhibited the best resistancestrain response and the highest gauge factor. The electrical resistance-strain curve was also measured through a cyclic loading test involving 100000 cycles. Results indicated that the hysteresis behavior and drift in electrical resistance may have hindered accurate measurements of the strain during the stretching and releasing process, which needs to be corrected by using a compensation algorithm. To demonstrate the proposed stretch sensor, knee motions were monitored using a resistive-type stretch sensor implemented on athletic cloth. [ABSTRACT FROM AUTHOR]

The results of studying the thermal emf of composites Cd3As2 + n mol % MnAs (n = 10, 20, 30, 44.7) at high pressures up to 50 GPa are presented. In the pressure ranges of P = 28–35 GPa (n = 10, 20), 20–35 GPa (n = 30), and 30–35 GPa (n = 44.7), all the materials studied exhibit specific features in the behavior of the thermal emf S(P) (extrema, inflection points on the curves or hysteresis). At a pressure exceeding 40 GPa, the thermal emf changes weakly or barely changes with an increase and a subsequent decrease in pressure. [ABSTRACT FROM AUTHOR]

In commercial forest plantations dominated by Norway spruce (Picea abies L. Karst), the typically densely rooted forest floor and a poor understory contribute to the formation of surface or shallow hypodermic runoff, which limits the redistribution of infiltrated water to deeper soil layers. Pit-mound microrelief is a natural legacy in forest soils that originate from historical tree uprootings. This paper analyses the hydrological processes associated within the pit-mound microrelief based on the monitoring of soil electrical resistance (Rx). In two forested slopes, paired-tube profile probes were used to monitor the dynamics of Rx along four transects through pit-mound pairs at different soil depths. Cross-corelation analysis was used to detect the time-lag responses of deeper soil layers as compared to surface horizons within 15 pre-selected precipitation periods per site. Unlike other microsites, the Rx of deeper soil layers at pit microsites were mostly correlated to the Rx of surface horizons with a time lag of 0–6 h, demonstrating a fast redistribution of infiltrated water throughout the soil profile. Our results indicate that the pit-mound microrelief on forested slopes can positively contribute to the retention and redistribution of infiltrated water to the subsoil, not only through direct infiltration from the soil surface but also likely by the disruption and redirection of shallow lateral flow. Thereby, the pit-mound microrelief may facilitate groundwater recharge similarly as the technical measures that are currently used in arid and semiarid regions. [ABSTRACT FROM AUTHOR]

In equipment for the contact butt welding of rails, innumerable parameters (input factors) affect the quality of the welded joint. That prevents complete selection of the optimal welding conditions. By studying the processes in the spark gap (the formation of microcontacts, increase or decrease in their cross-sectional area, and the explosion of existing microcontacts), the heat released in welding may be determined, and its uniformity may be assessed. On that basis, a smaller set of factors affecting the quality of the weld may be selected. Extensive statistical data are used in studying the processes in the spark gap during the contact butt welding of rails of type R65 and category DT350 on a K1000 welding machine. Analysis shows that there is no relation between the welding current and the plate motion in the welding machine. The welding current is assumed to be randomly distributed; it varies as a result of the formation, existence, and explosion of numerous brief electrical contacts. Analysis of the frequency distribution shows that the spark gap's resistance does not conform to a normal distribution. As the sample is enlarged, deviation from normal form increases. Visually, the histogram corresponds to a gamma distribution. On the basis of a gamma distribution, the welding current in contact butt welding is simulated. The results will be used to model the thermal processes and to predict the structure of the seam and the thermal-influence zone in the welding of rails. [ABSTRACT FROM AUTHOR]

This study obtained basic data describing the effects of maintenance of conductive textiles by investigating their electrical resistances and surface characteristics during wear and maintenance using clothes washers, dryers, and steam clothing care systems. To replicate the clothing maintenance process, a total of 20 cycles were conducted by washing with or without detergent followed by tumble- or line-drying. When detergent was used during washing, its ingredients interacted with the conductive textiles, thereby increasing their resistances. Therefore, it is recommended that a reduced quantity of detergent be used as it is otherwise difficult to wash clothes without using detergent. The optimal drying method was found to be dependent on the conductive textile fiber type; tumble-drying is recommended for hydrophilic textiles such as cotton fabrics, whereas line-drying is recommended for textiles containing polyurethane. Conductive textiles were found to be better maintained by the steam clothing care system than by the conventional clothes washer and dryer. However, because the use of a steam clothing care system alone cannot effectively remove soils from clothes, conductive textiles should be maintained by reducing the number of conventional washing and drying cycles and increasing the use of steam clothing care to achieve the expected smart clothing lifespan. Tensile tests were then conducted up to the maximum elongation of each textile to identify the changes in resistance during the wear process. The initial electrical resistances of nearly all of the conductive textiles showed an insignificant change at the maximum elongation; only the knitted textile with a high polyurethane content exhibited a significant change in electrical resistance in the lengthwise direction. The results of this study are expected to contribute to the development of smart clothing that can withstand day-to-day wear and maintenance. [ABSTRACT FROM AUTHOR]

The kinetics of damage accumulation in a D16ch sheet aluminum alloy (Al–Cu–Mg system) at various stages of static loading is investigated using a combined technique, which includes the detection of acoustic emission (AE) signals, structural studies, and the determination of electrical resistance and an eddy-current parameter. The dependences of these characteristics on the relative strain demonstrate the presence of four stages of specimen fracture. Correlation exponential dependences of the electrical resistance and the eddy-current parameter on damage are obtained, and they can be used to diagnose the state of the material. [ABSTRACT FROM AUTHOR]

The equiatomic FeCoNiCuMn high entropy alloy (HEA) was prepared by vacuum arc-melting under argon atmosphere, and the as-cast alloy was subsequently annealed at 850 °C and 1000 °C for 2 and 12 h. The annealing effects on the microstructure, magnetic, electrical, and mechanical properties were investigated. Based on the microstructural analysis, three major phases were found in different conditions; (Fe, Co)-rich phase, Cu-rich phase, and homogenized solid solution phase. This HEA showed excellent soft magnetic properties (proper saturation magnetization (40 emu/g), low coercivity (7 Oe) and low magnetic remanence ratio (0.03)) and high electrical resistivity (287 µΩ.cm) with proper strength and good ductility (41%). All these properties together make FeCoNiCuMn HEA better than that of the most reported soft magnet HEAs, and it can be used as a soft magnetic material in the future. [ABSTRACT FROM AUTHOR]

The work presents the results of studies of the structure and microhardness during annealing of cast and microcrystalline (MC) Al–2.5%Mg–Sc–Zr alloys with a total Sc and Zr content of 0.32%. The Sc content varies from 0.1 to 0.22% with an interval of 0.02%, and the Zr concentration in the alloy changes proportionally. In the initial state, the cast alloys are characterized by a homogeneous coarse-grained macrostructure. MC alloys are obtained by equal-channel angular pressing (ECAP) and have a homogeneous fine-grained structure in the initial state. The temperature of the beginning of recrystallization of MC alloys is determined. The mechanisms and temperature of the beginning of solid-solution decomposition in the cast and MC alloys are determined according to the Johnson–Mehl–Avrami–Kolmogorov model. It is found that the partial replacement of scandium with zirconium leads to a steady increase in the thermal stability of solid solution of Sc and Zr in aluminum. [ABSTRACT FROM AUTHOR]

Nickel Titanium Naval Ordinance Laboratory (NiTiNOL) is widely called as a shape memory alloy (SMA), a class of nonlinear smart material inherited with the functionally programmed property of varying electrical resistance during the transformation enabling to be positioned as a sensing element. The major challenge to instrument the SMA wires is to suppress the wires' nonlinearity by proper selection of two important factors. The first factor is influenced by the mechanical biasing element and the other is to identify the sensing current for the sensing device (SMA wires + biasing). This paper focuses on developing SMA wires for sensing in different orientation types and configurations by removing the non-linearity in the system's output by introducing inverse hysteresis to the wires through the passive mechanical element. [ABSTRACT FROM AUTHOR]

We have developed novel hydrothermal (HT) and hydrothermal microwave (HTMW) processes for the synthesis of nanocrystalline cadmium selenide via reduction using glucose and sodium sulfite. The materials thus obtained have been characterized by X-ray diffraction, CHNS analysis, and electron microscopy. The results demonstrate that they crystallize with a cubic and/or hexagonal symmetry and are nanocomposites containing 14 to 60 wt % organics. Varying synthesis conditions (temperature, composition of the starting mixture, and reaction time) allows one to obtain samples with sizes of coherent scattering regions from 6 to 80 nm. The use of the HTMW process reduces the synthesis time to 15 min in comparison with HT synthesis. The electrical resistance of nanocomposites, measured by the microwave loss method is 10–4 to 10–3 Ω cm, which is considerably lower than the resistivity of corresponding CdSe crystals. The data obtained in this work can be accounted for by the presence of carbon-containing components of the composite, which constitute a shell of particles. The increase in the cross-sectional area of "carbon channels" with decreasing nanoparticle size leads to an increase in the electrical conductivity of the material. [ABSTRACT FROM AUTHOR]

Repair of composite materials is an important cost savings for the aviation industry, and it is also very important to monitor the repaired structure. In this paper, a novel micro-nano sensor which is combined with Flexible Printed Circuit and Buckypaper (BP) sensor is introduced, and has the characteristics of multidirectional, real time and high sensitivity. These sensors are used to monitor the strain at different positions on the composite repair structure. The piezoresistive response of BP sensor is obtained and the main working mechanism of BP sensor is explained. Experiments show that this sensor can preliminarily judge the damage position and degree of the repaired structure, and monitor whether it reaches the strength limit. And it can judge the loading history of the structure. This ensures the safety of the repaired structure in the process of continuous service to a certain extent. [ABSTRACT FROM AUTHOR]

In the coking of heavy tar at 450–550°C, the influence of added carbon nanotubes on the yield of petroleum coke is studied. The properties of the resulting coke–nanotube composite are determined. Electron-microscopic data show that, in coking a mixture of heavy tar and nanotubes, the petroleum coke is reinforced by carbon nanotubes. Adding carbon nanotubes to heavy tar decreases its sulfur content. The drop in sulfur content of the petroleum coke is associated with the transfer of sulfur to hydrogen sulfide and COS, which are removed with the gas phase. With increase in the content of carbon nanotubes in petroleum coke, the electrical resistance of the coke–nanotube composite declines. Adding 5% of carbon nanotubes to the heavy tar lowers the resistance of the coke produced by a factor of 20. [ABSTRACT FROM AUTHOR]

The study involved a series of experiments on the coking of vacuum residue (VR) and of a mixture of carbon nanotubes (CNTs) and VR in an autoclave at 400–550°C. Using XRD, TEM, and electrical resistivity measurements, the properties of petroleum coke (petcoke) and CNT/petcoke composite were investigated and compared with those after calcination in an inert atmosphere at 1000–1100°C. It was found that the coking of a 2.5% CNT/VR mixture reinforces the petcoke with the CNTs. The CNT/petcoke composite exhibits a slightly higher crystallinity than the petcoke. However, the resistivity of the CNT/petcoke composite was found to be more than an order of magnitude lower than that of the petcoke. After high-temperature (1000–1100°C) calcination, the difference in resistivity between the petcoke and the 2.5% CNT/petcoke composite becomes substantially lower. This is associated with a resistivity drop in the petcoke itself, which approximates the resistivity of the carbon nanotubes. It was also identified that the high-temperature calcination reduces the sulfur content in the CNT/petcoke composite, and this reduction is more dramatic than that for the petroleum coke. [ABSTRACT FROM AUTHOR]

Motivated by advances in flexible electronic technologies and by the endeavour to develop non-destructive testing methods, this article analyses the capability of computational multiscale formulations to predict the influence of microscale cracks on effective macroscopic electrical and mechanical material properties. To this end, thin metal films under mechanical load are experimentally analysed by using in-situ confocal laser scanning microscopy (CLSM) and in-situ four point probe resistance measurements. Image processing techniques are then used to generate representative volume elements from the laser intensity images. These discrete representations of the crack pattern at the microscale serve as the basis for the calculation of effective macroscopic electrical conductivity and mechanical stiffness tensors by means of computational homogenisation approaches. A comparison of simulation results with experimental electrical resistance measurements and a detailed study of fundamental numerical properties demonstrates the applicability of the proposed approach. In particular, the (numerical) errors that are induced by the representative volume element size and by the finite element discretisation are studied, and the influence of the filter that is used in the generation process of the representative volume element is analysed. [ABSTRACT FROM AUTHOR]

A material based on a (VCr)2AlC solid solution has been obtained for the first time by self-propagating high-temperature synthesis from a powder reaction mixture of vanadium(V) and chromium(III) oxides with aluminum and carbon (graphite). The synthesized material has been studied by X-ray diffraction and microstructural analyses. It has been shown that the product also contains vanadium and chromium carbides and intermetallics. The presence of these phases seems to be associated with the nonequilibrium character of the synthesis process due to a short "lifetime" of melt and its fast cooling and crystallization. The synthesized material is an electrical conductor, which demonstrates a metallic character of conductivity throughout the entire measured temperature range of 300–1300 K. The room-temperature specific resistance of the composite material based on a (Cr,V)2AlC solid solution is 1.14 µΩ m, which is higher than the specific resistance of the materials based on the Cr2AlC and V2AlC MAX phases. The microhardness of the synthesized material is 6.9 GPa. [ABSTRACT FROM AUTHOR]

The pathogenesis of virus-associated acute encephalopathy (VAE) involves brain edema caused by disruption of the blood–brain barrier (BBB). We aimed to develop an in vitro VAE model using an in vitro BBB model, to evaluate the dynamics of vascular dysfunction caused by tumor necrosis factor (TNF)-α. A co-culture model, consisting of Transwell®-grown human brain microvascular endothelial cells and pericytes, was treated with serially diluted TNF-α. Transendothelial electrical resistance (TER) was measured using cellZscope®. A permeability assay, using fluorescein isothiocyanate-conjugated sodium or dextran, was performed. Changes in claudin-5 localization and expression after TNF-α treatment were observed using immunofluorescence staining and western blot analysis. The TER decreased and permeability increased after TNF-α treatment; recovery time was dependent on TNF-α concentration. Claudin-5 was delocalized after TNF-α treatment and recovered in a TNF-α concentration-dependent manner. The expression of claudin-5 decreased 24 h after the TNF-α treatment and completely recovered 48 h after TNF-α treatment. Claudin-5 delocalization was likely associated with vascular hyperpermeability. To conclude, we evaluated vascular endothelial cell permeability and injury in VAE using an in vitro BBB model treated with TNF-α. This system can be useful for developing novel therapeutic strategies for VAE and designing treatments that target vascular permeability. [ABSTRACT FROM AUTHOR]