Electrical Resistivity Measurements Research Articles

Direct implementation of a frequency-programmable Josephson voltage standard to provide an SI traceable optical power scale

We have developed a technique to determine the electrical substitution power of a cryogenic optical radiant power detector, that directly implements a frequency-programmable Josephson voltage standard (FPJVS), thus reducing the traceability chain. The optical power detector and the Josephson voltage reference are combined inside a common cryogenic environment. We demonstrate the practicality of the technique by using a FPJVS to apply a known voltage across the resistive heater of a standard NIST cryogenic planar radiometric detector. The power applied to the detector heater is calculated from a measurement of the heater resistance and the known applied voltage. The FPJVS dc bias current source supplies dc current to the resistive heater. In this demonstration, the standard uncertainty of the substituted electrical power is limited by the uncertainty of the electrical heater four-wire resistance measurement at 4 K. The uncertainty due to the resistance measurement is 1 part in 105 out of a total uncertainty of 1 part in 104 (k = 2) on the 1 mW optical power measurement. We aim to develop the technique, to provide traceability to the International System of Units for the picowatt power measurement of single-photon emitters such as quantum dot sources.

Impact damage characterization approach for CFRP pipes via self-sensing

The growing usage of carbon-fiber-reinforced polymers (CFRPs) has necessitated the development of structural health monitoring (SHM) for ensuring their integrity and safe operation. This paper presents a novel technique for monitoring the structural health of 3D CFRP pipe structures subjected to multiple impacts based on real-time electrical resistance monitoring. Damage characteristics such as its location and type were identified using the monitoring data and machine learning techniques. Additionally, finite element analysis was deployed to rationalize the electromechanical behaviors of pipes with varying stacking types and thus different fracture mechanisms. Analysis of the electrical resistance data coincided with the results of the finite element analysis in terms of damage modes and types. Therefore, a simple real-time electrical resistance measurement can detect the damage type without numerical analysis. A damaged section was identified by comparing the intensity of the data. Through machine learning techniques, the timepoints of damage severity demarcation were accurately predicted within error of 10 s and accuracies over 96 %. The machine-learning tools applied are unsupervised, thus reducing the effects of data dependency, labeling, and imbalance, as well as ensuring flexibility and general applications. The proposed technique was able to detect the damage location, severity, and type in real-time; hence, it has various potential applications in structural health monitoring including CFRP materials and is one of the few methods used to assess 3D structure characterization using self-sensing, which can result in mature technology and the optimal operation of CFRP systems.

Structural Lightweight Concrete Containing Basalt Stone Powder

In spite of the demonstrated efficacy of basalt stone powder as a cost-effective and readily available additive in enhancing the mechanical properties and durability of ordinary-weight concrete, its application in Structural Lightweight Concrete (SLWC) remains unexplored. This study introduced a mixing design for SLWC incorporating Light Expanded Clay Aggregates (LECAs) and basalt stone powder with a subsequent evaluation of its strength and durability characteristics. The experimental procedure involved creating various samples, considering differing proportions of cement, water, basalt stone powder, sand, LECA, superplasticizer, and aerating agent. The compressive strength and density of the 28-day-cured concrete specimens were determined. An optimal SLWC with a compressive strength of 42 MPa and a density of 1715 kg/m3 was identified. The flexural and tensile strength of the optimal SLWC exceeded those of ordinary-weight concrete by 6% and 3%, respectively. Further evaluation revealed that the optimal SLWC exhibited 1.46% water absorption and an electrical resistivity of 139.8 Ohm.m. Notably, the high porosity of LECA contributed to the low durability of SLWC. To address this, cost-effective external coatings of emulsion and fiberglass were applied to enhance the durability of the SLWC. Four coating scenarios, including one-layer bitumen, two-layer bitumen, three-layer bitumen, and three-layer bitumen with fiberglass, were investigated. The measurements of electrical resistance and compressive strength revealed that the use of three layers of emulsion bitumen and fiberglass improved the durability of the concrete by over 90% when the SLWC was exposed to severe chloride attack. Consequently, the durability of the SLWC with an external coating surpassed that of ordinary-weight concrete.

Phase transition and comparative study of CuxCd1–xS (x = 0.8, 0.6, 0.4, and 0.2) nanoparticle system

Microwave-assisted chemical precipitation was used to prepare CuxCd1–xS (x = 0.8, 0.6, 0.4, and 0.2) nanoparticles mixture. The crystal structure, size, and surface morphology of the as-synthesized nanoparticles were studied using X-ray diffraction and SEM. Presence of copper, cadmium, and sulphur in proper ratios in the samples was confirmed by energy-dispersed X-ray analysis. DC electrical resistance measurements of all the samples in the temperature range of 300…500 K showed phase transition above a certain temperature.

Electrical Resistivity Measurements of Surface-Coated Copper Foils.

Due to the direct contact between the probe and sample, the contact of the four-probe method is important for the structural integrity of the sample and the accuracy of electrical resistivity measurements, especially for surface-coated metal foils with multilayered structures. Here, we analyzed the accuracy and stability of four-probe method probing on different sides of copper (Cu) foils covered with graphene (Gr). Theoretical simulations showed similar potential distributions on the probe tip when probing on the Cu and Gr sides. The resistivity of the Gr/Cu foil was 2.31 ± 0.02 μΩ·cm when measured by probing on the Cu side, and 2.30 ± 0.10 μΩ·cm when measured by probing on the Gr side. The major difference in the mean deviation is attributed to surface damage. In addition, the method of probing on the Cu side was sensitive to the resistivity changes of Gr induced by polymers with a dielectric constant range of 2~12, which is consistent with the calculations based on the random phase approximation theory. Our results demonstrated that the probing position on the metal side in the four-probe method can effectively protect the structural integrity of the functional surface-coated layer and maintain the high sensitivity of the measurement, providing guidance for the resistivity measurements of other similarly heterogeneous materials.

Pressure generation under deformation in a large-volume press

Abstract Deformation can change the transition pathway of materials under high pressure, thus significantly affects physical and chemical properties of matters. However, accurate pressure calibration under deformation is challenging and thereby causes relatively large pressure uncertainties in deformation experiments, resulting in the synthesis of complex multiphase materials. Here, pressure generations of three types of deformation assemblies were well calibrated in a Walker-type large-volume press (LVP) by electrical resistance measurements combined with finite element simulations (FESs). Hard Al2O3 or diamond pistons in shear and uniaxial deformation assemblies significantly increases the efficiency of pressure generation compared with the conventional quasi-hydrostatic assembly. The uniaxial deformation assembly using flat diamond pistons possess the highest efficiency in these deformation assemblies. This finding is further confirmed by stress distribution analysis based on FESs. With this deformation assembly, we found shear can effectively promote the transformation of C60 into diamond under high pressure and realized the synthesis of pure-phase diamond at relatively moderate pressure and temperature conditions. The present developed techniques will help improve pressure efficiencies in LVP and explore the new physical and chemical properties of materials under deformation in both science and technology.

Development of High-Sensitivity Thermoplastic Polyurethane/Single-Walled Carbon Nanotube Strain Sensors through Solution Electrospinning Process Technique

In this study, nanofibers obtained through the electrospinning process are explored for strain-sensing applications. Thermoplastic polyurethane (TPU) flexible structures were fabricated using the solution electrospinning process (SEP) technique. Subsequently, these structures were nanomodified with single-walled carbon nanotubes (SWCNTs) through immersion into an ultrasonicated suspension containing 0.3 wt% SWCNTs. The nanomodification aimed to impart an electrically conductive network to the structures. Micro-tensile tests and electrical resistance measurements were conducted to characterize the apparent mechanical and electrical properties, respectively. The fabricated structures demonstrated potential as wearable strain sensors for monitoring changes in strain across various applications. The samples exhibited excellent performance, high sensitivity, outstanding mechanical properties, and a broad stretching range. Scanning electron microscopy (SEM) observations provided qualitative insights into the activated conductive pathways during operation.

Comparison of the Impact of VRP-034 and Polymyxin B upon Markers of Kidney Injury in Human Proximal Tubule Monolayers In Vitro.

In this study, we assessed the impact of commercially available polymyxin B against VRP-034 (novel formulation of polymyxin B) using a validated in vitro human renal model, aProximateTM. Freshly isolated primary proximal tubule cells (PTCs) were cultured in Transwell plates and treated with various concentrations of the formulations for up to 48 h. The functional expression of megalin-cubilin receptors in PTC monolayers was validated using FITC-conjugated albumin uptake assays. Polymyxin B and VRP-034 were evaluated at six concentrations (0.3, 1, 3, 10, 30, and 60 µM), and nephrotoxicity was assessed through measurements of transepithelial electrical resistance (TEER), intracellular adenosine triphosphate (ATP) levels, lactate dehydrogenase (LDH) release, and novel injury biomarkers [kidney injury molecule-1 (KIM-1), neutrophil gelatinase-associated lipocalin (NGAL), and clusterin]. Additionally, histological analysis using annexin V apoptosis staining was performed. Our results indicated a significant decrease in TEER with polymyxin B at concentrations ≥10 μM compared to VRP-034. Toxic effects were observed from ATP and LDH release only at concentrations ≥30 μM for both formulations. Furthermore, injury biomarker release was higher with polymyxin B compared to VRP-034, particularly at concentrations ≥10 µM. Histologically, polymyxin B-treated PTCs showed increased apoptosis compared to VRP-034-treated cells. Overall, VRP-034 demonstrated improved tolerance in the aProximateTM model compared to polymyxin B, suggesting its potential as a safer alternative for renal protection.

A simple pure organic single-component molecular conductor, [HEDT-TTF-dc], based on protonic-defected dicarboxylic acid

Based on protonic-defected dicarboxylic acid, a simple pure organic single-component molecular conductor, [HEDT-TTF-dc] has been successfully synthesized. The neutral HEDT-TTF-dc molecules form two-dimensional conducting layers, which are connected by hydrogen bond interaction. The electrical resistivity measurement exhibits a semiconducting behavior with a low activation energy of 0.1 eV. The magnetic susceptibility can be fit by the singlet-triplet model, which provides with the small energy gap corresponding to the activation energy.

Ce3Bi4Ni3 – A large hybridization-gap variant of Ce3Bi4Pt3

The family of cubic noncentrosymmetric 3-4-3 compounds has become a fertile ground for the discovery of novel correlated metallic and insulating phases. Here, we report the synthesis of a new heavy fermion compound, Ce3Bi4Ni3. It is an isoelectronic analog of the prototypical Kondo insulator Ce3Bi4Pt3 and of the recently discovered Weyl-Kondo semimetal Ce3Bi4Pd3. In contrast to the volume-preserving Pt-Pd substitution, structural and chemical analyses reveal a positive chemical pressure effect in Ce3Bi4Ni3 relative to its heavier counterparts. Based on the results of electrical resistivity, Hall effect, magnetic susceptibility, and specific heat measurements, we identify an energy gap of 65–70 meV, about eight times larger than that in Ce3Bi4Pt3 and about 45 times larger than that of the Kondo-insulating background hosting the Weyl nodes in Ce3Bi4Pd3. We show that this gap as well as other physical properties do not evolve monotonically with increasing atomic number, i.e., in the sequence Ce3Bi4Ni3−Ce3Bi4Pd3−Ce3Bi4Pt3, but instead with increasing partial electronic density of states of the d orbitals at the Fermi energy. This work opens the possibility to investigate the conditions under which topological states develop in this series of strongly correlated 3-4-3 materials. Published by the American Physical Society 2024

An investigation into the vapour permeability and durability of natural renders on an earthen wall system

This paper describes a novel methodology for establishing the relative moisture performance of renders used to protect a novel walling system combining traditional dense cob with a low-density thermal cob. A new method of enhancing the thermal insulation of cob walls has been developed by an European Union (EU)-funded joint UK and French project called CobBauge. The external surface of traditional cob walls (comprising subsoil, fibre and water) is normally protected from driving rain by placing the walls on a short wall called a plinth, a pronounced eaves overhang and a breathable exterior render. As the low-density fibre and clay insulating layer in the CobBauge system differs from traditional cob, a method of establishing the moisture-related performance of a range of renders needed to be instituted to aid the materials selection process. A series of test panels were constructed with the thermal cob infill, faced by a number of render types. The panels were hung in an open position in a high exposure zone and the moisture content monitored using wood-block sensors, electrical resistivity and gravimetric measurements over a period of six months. The wood-block and electrical resistivity moisture measurements showed a good level of agreement with gravimetric measurements and showed a clear differentiation between the various render choices.

Clinical Use of Long-Term GnRH Agonist in Prepubertal Bitches: Effect on P4, E2 and Melatonin Serum Concentration before and During First Estrus

Abstract The aim of this study was to determine the length of the contraceptive period after the application of deslorelin implant (4.7 mg) in juvenile, prepubertal bitches and assess the effects on the hormonal status (P4, E2 and melatonin), as well as on the occurrence of normal physiological estrus. Twelve crossbred prepubertal female dogs (4 months of age) were divided into the two groups, the treated group (DESLO) and control (placebo) group (C). Hormone assays, vaginal microbiological and cytological smears and the measurements of electrical resistance of cervical mucus were performed once in 3 weeks until the first signs of proestrus, and every day during estrus. GnRH implant significantly postponed time of onset of estrus (633 ± 30,38 days vs. 143.80 ± 52,30 days, P<0.001). In estrus, DESLO group showed statistically higher E2 (34.58 pg/mL vs. 20.59 pg/mL, P<0.001) and melatonin serum concentration (45.86 pg/mL vs. 18.85 pg/mL, P<0.001) compared to the control group. The average P4 serum concentration had no statistically significant differences between groups. In conclusion, deslorelin implants do not cause “flare up” effect in perpubertal bitches, however, increase of E2 and especially melatonin serum concentrations show the need to explore the consequences and mutual influence of melatonin and deslorelin implants in the future.

Synthesis and Physical Properties of the Misfit Layered Compound (EuS)1.13(NbSe2)2.

A new misfit layered compound with the stoichiometry (EuS)1+δ(NbSe2)2 (δ ≈ 0.13) has been successfully synthesized. High-resolution transmission electron microscopy and powder X-ray diffraction confirm the misfit structure with (EuS)-(EuS) spacing of 18.30(1) Å. Magnetization, electrical resistivity, heat capacity, and thermal transport measurements show that the material is a heavily doped semiconductor or poor metal with a low thermal conductivity of ∼1 W/m K and an antiferromagnetic ordering transition at TN = 4.7 K. In contrast to the parent materials, the misfit is neither ferromagnetic nor superconducting down to T = 0.4 K. We find evidence of a field-driven transition to a ferromagnetic state due to reorientation of ferromagnetic EuS layers at μoH = 0.5 T at T = 2 K.

FFF print defect characterization through in-situ electrical resistance monitoring

Fused filament fabrication is a popular fabrication technique. Currently there is a need for in-situ monitoring modalities to gather real-time information on prints, both for quality control and closed-loop control. Despite current advancements, effective and affordable in-situ monitoring techniques for non-destructive defect detection of voids and bonding quality are still limited. This work demonstrates in-situ monitoring of fused filament fabrication through electrical resistance measurements as an alternative to thermal and optical methods. A new, easy-to-implement setup is demonstrated which measures the electrical resistance of a conductively doped filament between the nozzle and single or multi-electrodes on the bed. Defects can be located in an unprecedented way with the use of encoded axes in combination with the observed resistance variations throughout the part. A model of the anisotropic electrical conduction is used to interpret the measurements, which matches well with the data. Warping, inter-layer adhesion, under-extrusion and overhang sagging print defects can be observed in the measurements of parts with a complex geometry, which would be difficult to measure otherwise. Altogether in-situ electrical resistance monitoring offers a tool for optimising prints by online studying the influence of the print parameters for quality assessment and it opens up possibilities for closed-loop control.

Effects of Mn and Ru substitutions on the electrical properties and AC susceptibility of Tl(BaSr)CaCu2O7 superconductor

In this paper, the effects of M = Mn and Ru substitutions at the Tl site of Tl[Formula: see text]Mx(BaSr)CaCu2O7 (Tl-1212) on the electrical properties and AC susceptibility were investigated. The X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) methods were used to examine the phase and microstructure, respectively. All samples showed diffraction patterns with Tl-1212 as the major phase and an increase in the Tl-1223 phase with increasing Mn and Ru substitutions. The microstructure showed partial melting and randomly oriented grains in all samples. The electrical resistance measurements showed metallic normal state behavior for all samples. The zero-resistance transition temperature [Formula: see text] was the highest for x = 0.4 where [Formula: see text] was 107[Formula: see text]K and 90[Formula: see text]K for Mn and Ru substitutions, respectively. The superconducting transition, [Formula: see text] obtained from AC susceptibility measurements increased with Mn and Ru substitutions up to x = 0.4. Using Bean’s model, the current density at the peak temperature of the imaginary part of the AC susceptibility, [Formula: see text]([Formula: see text] was determined to be between 16 and 22[Formula: see text]A[Formula: see text]⋅[Formula: see text]cm[Formula: see text] for Mn, and between 15 and 19[Formula: see text]A[Formula: see text]⋅[Formula: see text]cm[Formula: see text] for Ru-substituted samples. Mn substitution showed a higher transition temperature compared with Ru. This study showed that optimization of the average Cu valence was achieved with Mn and Ru substitutions for x = 0.4 at the Tl site. The ionic radii of the substituting and substituted elements are important factors in enhancing the transition temperature of Tl(BaSr)CaCu2O7 superconductor.

In Situ Electrical Resistance Measurement of Pure Titanium During Severe Plastic Deformation by High‐Pressure Sliding

In this study, in situ measurements of electrical resistance in pure Ti during severe plastic deformation (SPD) under high pressures are presented. The process of high‐pressure sliding (HPS) is adopted for the SPD so that straining is feasible under various pressures covering α to ω allotropic phase transformation in pure Ti. Anvil surfaces are coated by a plasma‐sprayed alumina layer to maintain electrical insulation between the sample and the anvils during HPS operation. The electrical resistance increases continuously with straining by the HPS processing but the increase in the electrical resistance is more pronounced as the applied pressure increases, particularly when the ω phase formation occurs. The phase transformation is evidenced by X‐Ray diffraction analysis as well as in situ static heating experiment. The continuous increase in the electrical resistance suggests that there is neither critical strain nor avalanche for the phase transformation to the ω phase.

Resistance analysis of laser-welded aluminum lead and tab for electric vehicle battery: Experiment and simulation

In pouch-type Li-ion batteries used in electric vehicles, battery cell tabs are electrically connected to an external lead of the same substance. Laser welding is a promising technique for joining these materials. This study investigates the fundamental question of whether electrical resistance measurements can be used to reliably estimate the welding state. An Al lead (400 μm thick) was welded spot-by-spot to a stack of 30 Al tabs (each tab 13 μm thick) using a laser beam incident on the lead surface. By adjusting the laser irradiation conditions, three different welding states (shallow, intermediate, and deep states) were intentionally produced. However, these structures exhibited no appreciable difference in the resistance measured across the welded region. The resistance was on the order of 10−4 Ω regardless of the welding state. Simulations were conducted for various joint structures, including those with voids, to derive the current flow through the structures and joint resistances. The simulation results corresponded well with the experimental results. Our study indicates that the electrical estimation of the welding state is challenging, because extremely low resistances are obtained even if the lead and tab are locally connected with narrow current paths.

Electrical resistivity and magnetoresistance of Sr3Fe2+xMo1–xO9–3x/2 (x = 0.45, 0.60, and 1.00) prepared by the solid-state reaction

In this paper, we focus on understanding the behavior of the temperature dependence of electrical resistivity (ρ) and magnetoresistance (MR) in Sr3Fe2+xMo1–xO9–3x/2 perovskites with x = 0.45, 0.60, and 1.00. Three polycrystalline materials were synthesized using conventional solid-state reaction techniques. Rietveld analysis of room-temperature X-ray diffraction data reveals that all three compositions crystallize in tetragonal symmetry; where x = 0.45 and 0.60 undergo an I4/mcm space group, while x = 1.00 adopts a P4/mmm space group. Electrical resistivity measurements carried out at magnetic fields (0 and 1 T) reveal the presence of a transition from the ferromagnetic phase to the paramagnetic phase in the vicinity of the TMI. The metal-insulator transition temperature (TMI) decreases with increasing Fe content and rises slightly with changing magnetic field from 0 to 1 T. The magnetoresistance (MR) of the SrFeO3–δ sample (x = 1.00) has a large value of about 63.6 %, indicating that it can be exploited for certain devices. A variety of theoretical models are used to study the behavior of electrical resistivity in various temperature ranges, showing excellent agreement with experimental results.

Applicability of electrical resistivity measurements for monitoring biocementation treatment in soils

In this paper the use of ER measurements in soils in the context of biocementation, is investigated considering its use as an indicator of treatment efficiency measured trough the presence of biocement, or to provide information about the presence of chemical by-products during or after final washing operations. The electrical resistivity of a slightly biocemented sand was analyzed on a laboratory scale test conceived to reproduce field measurements conditions such as varying degrees of saturation and the presence of chemical by-products in the pore fluid. The results confirmed that, independently from the degree of saturation, the nature of the pore fluid was the parameter that affected most the electrical resistivity measurements, and the presence of calcium carbonate affecting soil structure was detected only after removal of the treatment by-products by a complete final soil washing using water. From a practical point of view this non-destructive technique is more adequate to be used mainly at the end of the treatment, to check that complete soil washing has occurred, rather than checking the presence of bio-cement specially if the amount precipitated is not very high as it was the case of the tests performed.

The barrier-protective effect of β-eudesmol against type 2-inflammatory cytokine-induced tight junction disassembly in airway epithelial cells.

Allergic inflammation, which is the pathogenesis of allergic rhinitis and asthma, is associated with disruption of the airway epithelial barrier due to the effects of type 2 inflammatory cytokines, i.e. interleukin-4 and interleukin-13 (IL-4/13). The anti-allergic inflammatory effect of β-eudesmol (BE) on the tight junction (TJ) of the airway epithelium has not previously been reported. Herein, the barrier protective effect of BE was determined by measurement of transepithelial electrical resistance and by paracellular permeability assay in an IL-4/13-treated 16HBE14o- monolayer. Pre-treatment of BE concentration- and time- dependently inhibited IL-4/13-induced TJ barrier disruption, with the most significant effect observed at 20 μM. Cytotoxicity analyses showed that BE, either alone or in combination with IL-4/13, had no effect on cell viability. Western blot and immunofluorescence analyses showed that BE inhibited IL-4/13-induced mislocalization of TJ components, including occludin and zonula occludens-1 (ZO-1), without affecting the expression of these two proteins. In addition, the mechanism of the TJ-protective effect of BE was mediated by inhibition of IL-4/13-induced STAT6 phosphorylation, in which BE might serve as an antagonist of cytokine receptors. In silico molecular docking analysis demonstrated that BE potentially interacted with the site I pocket of the type 2 IL-4 receptor, likely at Asn-126 and Tyr-127 amino acid residues. It can therefore be concluded that BE is able to prevent IL-4/13-induced TJ disassembly by interfering with cytokine-receptor interaction, leading to suppression of STAT6-induced mislocalization of occludin and ZO-1. BE is a promising candidate for a therapeutic intervention for inflammatory airway epithelial disorders driven by IL-4/13.