Electrical Properties Research Articles

Practical approach for sand-shale mixtures classification based on rocks multi-physical properties

Sandstones are the most common reservoir rocks, providing reservoirs for oil and gas and serving as reservoirs for groundwater. The Gulf of Mexico is known for its sand-shale mixtures and potential for its oil and hydrate gas resources in sandstone units. Understanding these variations is essential for assessing hydrocarbon potential and unconventional prospectivity. In this study, we utilized the Elastic, Electrical, and Radioactive (EER) properties of rocks for lithological categorization of well logging data, leading to the development of a novel rock physics template. The electrical and radioactive properties of the rocks facilitated a broad lithological classification, while their elastic characteristics helped distinguish between porous and low-porosity zones. Electrical and radioactive properties are utilized for well data classification because in sandstone formations, there is a decrease in log gamma and an increase in log resistivity. As a result, these opposing shifts in the two geophysical logs enhance the spread of data points on the lithological resistivity-gamma ray scatter plot, thereby simplifying the process of lithological categorization. Ultimately, the well logging data was sorted into three distinct categories: low shale sands (shale volume < 30 %), sand-shale mixtures (shale volume = 30 to 80 %), and shale-dominated areas. Subsequently, the Thomas Stieber model was employed to identify the types of clay minerals present in both sandstones and sand-shale mixtures. The model's findings revealed that dispersed type clay minerals are predominantly found in sandstones, with laminar and structured types being relatively rare. However, in sand-shale mixtures, both dispersed and laminar clays observed.

High-temperature thermochemical conversion of iron ore tailings into diopside and akermanite-based composite materials

Iron ore tailings (IOTs), the residue materials generated during iron ore processing, pose environmental challenges due to their massive volume and potential impact on ecosystems. This study proposes a sustainable approach to manage and utilize this solid waste by converting it into value-added composite materials through high-temperature thermochemical reactions. Experiments are conducted in a tubular reactor at various reaction temperatures and times, and the resulting product samples are comprehensively characterized to elucidate their chemical compositional, physical, microstructural, thermal, and electrical properties. The results reveal that at optimal reaction temperatures (1230–1260 °C) and reaction times (20–120 min), the synthesized product is predominantly composed of diopside (CaMgSi2O6) and akermanite (Ca2MgSi2O7). Additionally, we demonstrate that the product can be diopside-rich or akermanite-rich when blending silica and MgO powders into the IOTs to control the starting material composition, opening a promising avenue for large-scale sustainable utilization of industrial solid waste.

Nanostructure-induced functional combination of vanishing magnetostriction and magnetic softness in ferromagnetic (GaNi)xCoCrFe (x = 0.4–1.6) high-entropy alloys

Searching for high-entropy alloys with functional properties that emerge from their multi-scale structure, we have investigated the (GaNi)xCoCrFe (x = 0.4–1.6) system. We have characterized structure, microstructure, nanostructure and chemical composition of the individual phases in the multi-phase alloys and determined their magnetic, magnetostrictive and electrical properties. We found that the alloys are ferromagnetic and exhibit functional combination of magnetic softness and vanishing magnetostriction, classifying them as energy-efficient “supersilent” materials (inaudible to a human ear) for alternating-current (AC) electromagnetic applications in the audio-frequency range. The alloys develop a two-phase structure, a face-centered cubic (fcc) and a body-centered cubic (bcc), where the fcc phase fraction decreases, while the bcc fraction increases with the increasing (GaNi)x content. Ferromagnetism of the alloys originates from the highly nanostructured bcc phase, with the ferromagnetic Curie temperatures in the range TC = 750–700 K, depending on x. The fcc phase is not nanostructured and is paramagnetic at room temperature, but undergoes a spin glass transition at Tf≈6.4 K. The magnetic softness and vanishing magnetostriction of the alloys are both nanomagnetic phenomena. The magnetic-softness and magnetostriction parameters of the x = 1.3 and 1.6 alloys make them relevant for supersilent AC applications at low frequencies.

Electrical Properties and Thermo-Oxygen Stability of Polypropylene Modified by Polydopamine

Electrical Properties and Thermo-Oxygen Stability of Polypropylene Modified by Polydopamine

An innovative process for clean ammonium-free vanadium precipitation and one-step preparation of vanadium dioxide based on hydrothermal enhancement of organic alcohols

As a transition metal oxide, VO2 has excellent optical and electrical properties and is widely used in many fields. The production of VO2 by the reduction of NH4VO3 and V2O5 will inevitably produce ammonia–nitrogen wastewater and NH3 emission during the production of NH4VO3 and V2O5, which will cause serious environmental pollution and will increase economic costs. The large-scale and low-cost synthesis of VO2 still faces great challenges. In this paper, VO2(B) was successfully prepared by a one-step hydrothermal method using NaVO3 as the vanadium source and CH3CH2OH as the reducing agent, and the optimal conditions for vanadium precipitation are as follows: vanadium concentration = 30 g/L, CH3CH2OH dosage = 20 % (percentage of solution volume), initial pH = 1, reaction temperature = 220 °C, reaction time = 12 h. The vanadium precipitation efficiency under the optimal conditions could reach 98.93 %, and the purity of VO2(B) could reach 98.59 %. The precipitation products were characterized by XRD, TG, FTIR, XPS, and SEM-EDS. The mechanism of VO2(B) preparation by ethanol reduction was proposed. This process is characterized by green, clean, and high efficiency. At the same time, the vanadium precipitation effect and vanadium precipitation products of various alcohols were studied to provide technical and theoretical support for the preparation of VO2(B).

Modified Complex Electrical Resistivity Technique: Applications to Saturated and Unsaturated Soils

Abstract Direct current (DC) electrical resistivity is a common laboratory soil characterization method to support geotechnical infrastructure design and to supplement site investigations. The complex electrical resistivity method has the potential to provide additional electrical soil properties to enhance electrical soil characterization. Both methods are conventionally performed under fully saturated soil conditions; however, many environments exist where soil is not fully saturated, such as ballast structure supporting railways. In this study, a new experimental setup featuring a current enhancing agent (agar) for complex electrical resistivity testing is evaluated by testing five different soil specimens reconstituted at saturated and unsaturated conditions. Results showed that the new experimental setup is valid and can be used to obtain repeat measurements, particularly for specimens reconstituted in the unsaturated conditions where the traditional DC electrical resistivity setup yields results that are unreliable. This is one of the very few studies where tolerances for triplicate specimens are reported to establish differences in measurements from sample preparation versus discernable variability between different geomaterials. Additionally, all results are supported by a Cole-Cole model. The results show that the additional data collected in a complex electrical resistivity test can be used to differentiate different soil types that are ambiguous with the DC electrical resistivity method. The additional data have the potential to more fully characterize the electrical properties of saturated and unsaturated soils, as well as to help distinguish unique geophysical signatures of various geomaterials to enhance a geophysical site investigation for identifying soil variability in the subsurface.

Flexible Ag@Au core–shell nanowires electrode fabrication with controllable nanogold size and thickness on silver nanowires/PDMS substrate toward enhanced ethanol electrooxidation

The synthesis of gold nanowires (AuNWs) is challenging due to difficulties in obtaining AuNWs of variable diameters and lengths. In this study, an effective approach to fabricating AuNWs with controllable lengths and diameters was developed on a flexible silver nanowires (AgNWs)/polydimethylsiloxane (PDMS) substrate. Gold nanoparticles were uniformly electrodeposited onto the flexible AgNWs/PDMS to form bimetallic Ag@Au core–shell NWs/PDMS. The results showed that the diameters and the lengths of the Ag@Au NWs were easily fine-tuned. The flexible Ag@Au NWs/PDMS electrode exhibited excellent mechanical, electrical, and electrochemical properties. In ethanol oxidation reaction (EOR), the Ag@Au NWs/PDMS achieved a peak current density of 28541.55 μA cm−2 (10 times higher than that of a commercial Au electrode) and 63.39% retaining activity in a stability test by chronoamperometry (over 2 times stable than values in literature). Finally, EOR and chromium (VI) determination by the Ag@Au NWs/PDMS in flexible integrated electrodes were performed to showcase the versatile feasibilities of this new material.

Anti-plane Yoffe-type crack in flexoelectric material

This work investigates the deformation and polarization fields around a finite anti-plane shear (mode III) crack growing dynamically under steady-state conditions. The leading tip of this finite crack breaks the material while the trailing tip heals it. This fast moving finite crack (referred to as a rupture “pulse” in the geophysics literature) propagates with a constant velocity and with the mechanical and the electrical fields that remain invariant with respect to an observer moving with the crack-tips. This problem belongs to the first type of steady state crack growth problems according to the classification of Freund. The “prototype” problem which refers to an isotropic, body subjected to fracture under tensile loading was first proposed and solved by Yoffe, while finite cracks (or shear pulses) were also analyzed by Freund and by Rice. In the above cases the material was assumed to be linear elastic. Our analysis extends these studies to flexoelectric materials, and it is both theoretical and numerical. It discusses the asymptotic structure of the crack-tip displacement and the polarization fields; it calculates the dynamic energy release rate and presents their dependence on crack-tip velocity. Comparisons are made to the available, classical, elasto-dynamic solutions and to the static case. The influence of the electrical properties of the material on strengthening is also analyzed. Dynamic fracture of flexoelectric materials is of relevance to both the study of earthquake source mechanics and to the analysis of the reliability of micro-electronic devices. This is because both rocks and ceramics are flexoelectric. Indeed, during earthquake rupture processes, dynamic, in-plane shear (Mode-II) and out of plane shear (Mode-III), cracks propagate along faults and exhibit both mechanical and electrical polarization signatures. At an entirely different length scale, flexoelectric ceramics are currently used as sensors and transducers and can experience dynamic shear failure along interfaces when subjected to dynamic loading (e.g. impact.). Failure by dynamic fracture can be detrimental to both their mechanical reliability and electrical functionality.

Molecular dynamics simulation study to investigate electrical properties of plumbene

ABSTRACT Plumbene, the new 2D structure of lead, single-layered with a hexagonal arrangement of atoms draws the attention of researchers around the globe. We have designed a plumbene sheet using multi-scale modelling i.e. nonequilibrium molecular dynamics (NEMD) simulation methods to determine the electrical properties of plumbene. The effects of varying sample sizes and temperatures on the electrical properties of plumbene using NEMD are studied here. It is observed from 298 K to 318 K electrical conductivity of plumbene ranges from 2.7792 × 10−14 S/m to 1.2012 × 10−13 S/m, with a dwindling nature. Almost static electrical resistivity from 298 K to 378 K is noticed, afterwards a sudden sharp increase till 398 K. The Lorenz number of plumbene from 298 K to 318 K shows reverse results with its electrical conductivity under similar experimental conditions. The electrical conductivity of plumbene sheets at 298 K with 600Å to 1050Å ranges from 0.17794 × 10−14 S/m to 4.7696 × 10−14 S/m. Only at 750Å sample size is a sharp jump is noticed. A reverse trajectory is observed for both electrical resistivity and Lorenz number of plumbene sheet samples. In these two cases, the sharp jump is observed at 1000Å. Our results will be helpful for the effective utilisation of plumbene in targeted applications of electrical engineering fields.

Effect of Li2O on physical, structural, thermal, optical, and electrical properties of mixed alkali borate glasses containing silver nanoparticles

In this work, mixed alkali borate glasses doped with Li2O were prepared with a molar composition of (75-x) B2O3-15Na2O-8CaO-1V2O5-1AgCl-xLi2O; x = 0, 5, 10, 15, and 20 mol% by using traditional melt-quenching process. X-ray diffraction studies confirmed the amorphous nature of the samples. Upon Li2O doping the glass density, measured at ambient temperature, increases from 2.336to 2.518 g/cm3, while molar volume decreases from 29.637 to 24.337 cm3/mol. The direct and indirect band gap energies determined using UV–Visible absorption analysis was in the range 3.000 –3.285 eV and 2.910–3.218 eV respectively. The DTA measurements indicated that with Li2O addition the thermal stability of the glasses has improved. FTIR study revealed the vibrational modes corresponding to the functional groups present in the glasses. The DC conductivity of the samples (measured at 588 K) was found to increase from 2.394 x 10-4 to 3.987 x 10-4 Ω-1m-1with Li2O content. The temperature dependency of DC conductivity followed Mott’s Small Polaron Hopping (SPH) model at high temperature and Variable Range Hopping (VRH) model at low temperatures. The linear fit of the data to the SPH model yielded the activation energy (W) values in the range 0.152 to 0.693 eV, whereas the density of states at Fermi level evaluated by the VRH model was in the order of 1030 eV-1m-3. The improved electrical conductivity of the prepared Li doped glasses together with their good thermal stability and transparency render them as potential candidates for optoelectronics device applications.

Self-assembled nest-like BN skeletons enable polymer composites with high thermal management capacity

The lagging development of thermally conductive but electrically insulating materials has become a bottleneck problem for the next generation of advanced high-power density electronic devices. Although second-phase reinforced composites are promising materials for addressing thermal management issues, the inherent mechanism of severe phonon scattering at the interphase results in actual thermal conductivity enhancement efficiency far below expectations. Here, we report a high-performance polymer composite with a nest-like interconnected boron nitride skeleton. This nest-like interconnected BN skeleton without mechanical contact can provide high-efficiency and long-distance phonon transport channel, realizing high thermal conductivity of 1.827 W m-1 K-1 in polymer composite with ultra-low content (4.7 vol%). Meanwhile, the EP/ nest-like BS composites possess ideal electrical properties and dimensional stability. In the actual heat dissipation process of LED chips, the optimal composite material as the thermal interface material can display a temperature drop of more than 34.8% compared to neat epoxy, which proves the broad application prospects of this strategy in advanced electronic devices.

Mechanical, Durability and Electrical Properties of Steel Fibers Reinforced Concrete

Mechanical, Durability and Electrical Properties of Steel Fibers Reinforced Concrete

Enhancing Low-Temperature Sensor Applications: Synergistic Effects of Ni Doping and SnO2 Interlayer on Spin-Coated ZnO Thin Films on Glass Substrate

This study investigates the effects of Nickel doping and a SnO2 interlayer on the structural, morphological, optical, and electrical properties of ZnO thin films. Undoped and Ni-doped ZnO films were fabricated on glass substrates, with and without an SnO2 interlayer, using the sol-gel spin coating method. The samples—denoted as ZG (undoped ZnO), NZG (Ni-doped ZnO), ZSG (undoped ZnO with SnO2 interlayer), and NZSG (Ni-doped ZnO with SnO2 interlayer)—underwent comprehensive characterization via XRD, AFM, PL, UV-Vis spectroscopy, Hall effect measurements, Hot probe, and Two-point method. XRD analysis confirmed successful Ni incorporation and enhanced ZnO crystallinity, particularly in the presence of the SnO2 interlayer. AFM analysis revealed improved grain distribution and size due to the synergistic effects of Ni doping and the SnO2 interlayer. UV-Vis results indicated significant impacts on transparency and the Urbach energy, with Ni doping alone broadening the bandgap. PL measurements showed that the synergistic effects quenched UV luminescence associated with the glass substrate, enhancing visible luminescence. Chromaticity analysis suggested that ZSG and NZSG samples are suitable for warm blue region applications. Electrical measurements revealed n-type conductivity across all films except NZG, with Ni doping increasing resistivity. Additionally, the ZSG (PTC) sensor exhibited a slightly higher sensitivity (0.3852 Ω/°C) compared to the NZSG sensor (0.3782 Ω/°C), with a similar trend observed in NTC sensors. These findings suggest that Ni-doped ZnO films with SnO2 interlayers could potentially serve as thermistors and RTDs, offering promising applications in temperature sensing and optoelectronics.

Conductive Nanocomposites Based on Graphene and Natural Polymers

This thesis focuses on the development of conductive nanocomposite materials based on graphene and natural polymers such as cellulose and chitosan. Graphene, a single layer of carbon atoms arranged in a honeycomb lattice, exhibits exceptional electrical, mechanical, and thermal properties, making it an attractive filler for polymer composites. However, the challenge lies in effectively dispersing graphene sheets within polymer matrices. The work presented explores new strategies for grafting polysaccharide chains onto oxidized graphite (graphene oxide) to improve its compatibility and dispersion in cellulose and chitosan matrices. The resulting composites were doped with gold or nickel nanoparticles to further enhance their electrical and catalytic properties. Detailed characterization techniques, including spectroscopic and microscopic methods, were employed to analyze the structure, morphology, and properties of the developed nanocomposites. The thesis is organized into three main parts: 1) a literature review on graphene, polysaccharides, and their biocomposites; 2) a description of the experimental materials and methods; and 3) a scientific discussion of the results, presented in the form of three research publications. The findings demonstrate the successful synthesis of conductive nanocomposites with improved compatibility and performance, opening up new avenues for the application of these sustainable and multifunctional materials in areas such as electronics, catalysis, and electromagnetic shielding.

Investigating the impact of nano copper on the electrical conductivity of aluminum: A comprehensive study utilizing ANN, genetic algorithm, and fuzzy logic methods

Nanotechnology has emerged as a transformative field in material science, offering unprecedented opportunities to enhance the electrical properties of conventional materials through the incorporation of nano-sized particles. In this extensive study, we explore the effects of varying weight percentages (1%, 2%, and 3%) and lengths (30 nm, 60 nm, 150 nm, and 250 nm) of nano copper on the electrical conductivity of aluminum (Al) across different temperatures (20°C, 50°C, and 100°C). Additionally, we compare the predictive capabilities of Artificial Neural Networks (ANN), Genetic Algorithms (GA), and Fuzzy Logic (FL) methods in forecasting the electrical conductivity variations of Al based on these parameters.

Investigating the impact of nano copper on the electrical conductivity of aluminum: A comprehensive study utilizing artificial neural networks

Nanotechnology has emerged as a transformative field in material science, offering unprecedented opportunities to enhance the electrical properties of conventional materials through the incorporation of nano-sized particles. In this extensive study, we explore the effects of varying weight percentages (1%, 2%, and 3%) and lengths (30 nm, 60 nm, 150 nm, and 250 nm) of nano copper on the electrical conductivity of aluminum (Al) across different temperatures (20°C, 50°C, and 100°C). Additionally, we investigate the predictive capabilities of Artificial Neural Networks (ANN) in forecasting the electrical conductivity variations of Al based on these parameters. Through a detailed analysis of experimental results and ANN modeling,

Investigating the impact of nano copper on the electrical conductivity of aluminum: a comprehensive study utilizing genetic algorithms methods

Nanotechnology has emerged as a transformative field in material science, offering unprecedented opportunities to enhance the electrical properties of conventional materials through the incorporation of nano-sized particles. In this extensive study, we explore the effects of varying weight percentages (1%, 2%, and 3%) and lengths (30 nm, 60 nm, 150 nm, and 250 nm) of nano copper on the electrical conductivity of aluminum (Al) across different temperatures (20°C, 50°C, 80°C, and 100°C). Additionally, GA method and Numerical correction factor and constitutive equation using Zener –Holloman parameter were employed for modeling the rheological behavior of Al based on these parameters.

Investigating the impact of nano copper on the electrical conductivity of aluminum: A comprehensive study utilizing fuzzy logic methods

Nanotechnology has emerged as a transformative field in material science, offering unprecedented opportunities to enhance the electrical properties of conventional materials through the incorporation of nano-sized particles. In this extensive study, we explore the effects of varying weight percentages (1%, 2%, and 3%) and lengths (30 nm, 60 nm, 150 nm, and 250 nm) of nano copper on the electrical conductivity of aluminum (Al) across different temperatures (20°C, 50°C, and 100°C). Additionally, we investigate the predictive capabilities of fuzzy logic methods in forecasting the electrical conductivity variations of Al based on these parameters.

Research of Graphene Electronics and its Applications

Imagine a material as thin as a single atom, yet stronger than steel and more conductive than copper. This is graphene, a two-dimensional wonder material with a unique monolayer hexagonal honeycomb lattice structure. Its exceptional electrical properties, particularly its high carrier mobility, have sparked widespread interest in the scientific community for potential applications in electronics.However, because its conduction and valence bands intersect at the Dirac point, it behaves as a zero-bandgap semimetal, limiting its use in electronic devices. Therefore, opening a bandgap has become a focal research task in the scientific community. This paper explains the inherent conductivity of intrinsic graphene and summarizes how doping can theoretically further enhance its conductivity. Through further research on the development of graphene doping methods, this article primarily introduces how adsorption doping and lattice doping techniques can open the bandgap of graphene. It analyzes the stability of different doping types to achieve their application in nanoelectronic devices.

Optical, electrical, dielectric and mechanical properties of microcrystalline cellulose/starch based biocomposite films

Abstract In this work, we have synthesized biocomposite films based on starch reinforced with microcrystalline cellulose (MCC) with different MCC/starch weight contents (0, 1, 3, 5, and 7 %). These films were characterized by various techniques such as X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), and energy-dispersive X-ray analysis (EDX), which showed dispersed and biocompatible structures for MCC and starch. It was found that the increase in MCC content (from 0 to 7 wt%) led to decreasing the water solubility, and reducing the absorption coefficients, transmission percentages and electrical conductivity. However, the improvement of dielectric and mechanical properties was demonstrated by decreasing the dielectric loss tangent and increasing the Young’s modulus, respectively making them suitable for dielectric and mechanical applications.